diff --git a/changelogs/raw/v0.3.0.cleaned.md b/changelogs/0.3.0/v0.3.0.cleaned.md
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diff --git a/changelogs/raw/v0.3.0.uncleaned.md b/changelogs/0.3.0/v0.3.0.uncleaned.md
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diff --git a/changelogs/master/20191003_reworked_aug_methods.md b/changelogs/0.4.0/20191003_reworked_aug_methods.md
similarity index 99%
rename from changelogs/master/20191003_reworked_aug_methods.md
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index 2cc15422d..32341749b 100644
--- a/changelogs/master/20191003_reworked_aug_methods.md
+++ b/changelogs/0.4.0/20191003_reworked_aug_methods.md
@@ -14,7 +14,7 @@
`imgaug.augmentables.batches.Batch`.
* Added method `fill_from_augmented_normalized_batch_()` to
`imgaug.augmentables.batches.UnnormalizedBatch`.
-* Added class `imgaug.augmentables.batches.BatchInAugmentation`.
+* Added class `imgaug.augmentables.batches._BatchInAugmentation`.
* Added method `_augment_batch_()` in `imgaug.augmenters.meta.Augmenter`.
This method is now called from `augment_batch_()`.
* Changed `augment_images()` in `imgaug.augmenters.meta.Augmenter` to be
diff --git a/changelogs/master/20191016_pooling_affects_maps.md b/changelogs/0.4.0/20191016_pooling_affects_maps.md
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diff --git a/changelogs/master/20191026_reworked_quantization.md b/changelogs/0.4.0/20191026_reworked_quantization.md
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diff --git a/changelogs/master/20191027_improve_invert.md b/changelogs/0.4.0/20191027_improve_invert.md
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diff --git a/changelogs/master/20191111_pickleable.md b/changelogs/0.4.0/20191111_pickleable.md
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diff --git a/changelogs/master/20191113_iterable_augmentables.md b/changelogs/0.4.0/20191113_iterable_augmentables.md
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diff --git a/changelogs/master/added/20191101_deterministic_list.md b/changelogs/0.4.0/added/20191101_deterministic_list.md
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diff --git a/changelogs/master/added/20191102_autocontrast.md b/changelogs/0.4.0/added/20191102_autocontrast.md
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diff --git a/changelogs/master/added/20191103_affine_shear_y.md b/changelogs/0.4.0/added/20191103_affine_shear_y.md
similarity index 94%
rename from changelogs/master/added/20191103_affine_shear_y.md
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index a111c0caf..68e471098 100644
--- a/changelogs/master/added/20191103_affine_shear_y.md
+++ b/changelogs/0.4.0/added/20191103_affine_shear_y.md
@@ -1,4 +1,4 @@
-# Affine Shear on the Y-Axis
+# Affine Shear on the Y-Axis #482
* [rarely breaking] Extended `Affine` to also support shearing on the
y-axis (previously, only x-axis was possible). This feature can be used
diff --git a/changelogs/master/added/20191103_equalize.md b/changelogs/0.4.0/added/20191103_equalize.md
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diff --git a/changelogs/master/added/20191103_identity.md b/changelogs/0.4.0/added/20191103_identity.md
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rename from changelogs/master/added/20191103_identity.md
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diff --git a/changelogs/master/added/20191105_affine_wrappers.md b/changelogs/0.4.0/added/20191105_affine_wrappers.md
similarity index 89%
rename from changelogs/master/added/20191105_affine_wrappers.md
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index 69aa0d3b0..3bf1451c8 100644
--- a/changelogs/master/added/20191105_affine_wrappers.md
+++ b/changelogs/0.4.0/added/20191105_affine_wrappers.md
@@ -1,4 +1,4 @@
-# Added Wrappers around `Affine`
+# Added Wrappers around `Affine` #484
* Added `imgaug.augmenters.geometric.ScaleX`.
* Added `imgaug.augmenters.geometric.ScaleY`.
diff --git a/changelogs/master/added/20191106_ooi_removal.md b/changelogs/0.4.0/added/20191106_ooi_removal.md
similarity index 99%
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index a498acf13..b96dc54ca 100644
--- a/changelogs/master/added/20191106_ooi_removal.md
+++ b/changelogs/0.4.0/added/20191106_ooi_removal.md
@@ -1,4 +1,4 @@
-# Removal of Coordinate-Based Augmentables Outside of the Image Plane
+# Removal of Coordinate-Based Augmentables Outside of the Image Plane #487
* Added `Keypoint.is_out_of_image()`.
diff --git a/changelogs/master/added/20191110_bb_polygon_conversion.md b/changelogs/0.4.0/added/20191110_bb_polygon_conversion.md
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diff --git a/changelogs/master/added/20200125_image_warnings.md b/changelogs/0.4.0/added/20200125_image_warnings.md
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diff --git a/changelogs/master/changed/20190929_rngs_polygon_recoverer.md b/changelogs/0.4.0/changed/20190929_rngs_polygon_recoverer.md
similarity index 65%
rename from changelogs/master/changed/20190929_rngs_polygon_recoverer.md
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index 84f4beab6..f6e90c68e 100644
--- a/changelogs/master/changed/20190929_rngs_polygon_recoverer.md
+++ b/changelogs/0.4.0/changed/20190929_rngs_polygon_recoverer.md
@@ -1,4 +1,6 @@
+# Improved RNG Handling during Polygon Augmentation #447
+
* Changed `Augmenter.augment_polygons()` to copy the augmenter's RNG
before starting concave polygon recovery. This is done for cleanliness and
- should not have any effects for users. #447
-* Removed RNG copies in `_ConcavePolygonRecoverer` to improve performance. #447
+ should not have any effects for users.
+* Removed RNG copies in `_ConcavePolygonRecoverer` to improve performance.
diff --git a/changelogs/master/changed/20191110_affine_translation_precision.md b/changelogs/0.4.0/changed/20191110_affine_translation_precision.md
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diff --git a/changelogs/master/changed/20200115_changed_defaults.md b/changelogs/0.4.0/changed/20200115_changed_defaults.md
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--- a/changelogs/master/changed/20200115_changed_defaults.md
+++ b/changelogs/0.4.0/changed/20200115_changed_defaults.md
@@ -1,4 +1,4 @@
-# Better default values #582
+# Improved Default Values of Augmenters #582
**[breaking]** Most augmenters had previously default values that
made them equivalent to identity functions. Users had to explicitly
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diff --git a/changelogs/0.4.0/fixed/20191003_fixed_typo.md b/changelogs/0.4.0/fixed/20191003_fixed_typo.md
new file mode 100644
index 000000000..ae766b793
--- /dev/null
+++ b/changelogs/0.4.0/fixed/20191003_fixed_typo.md
@@ -0,0 +1 @@
+* Fixed typo in image normalization. #451
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diff --git a/changelogs/master/fixed/20191124_fixed_cloud_layer_float.md b/changelogs/0.4.0/fixed/20191124_fixed_cloud_layer_float.md
similarity index 63%
rename from changelogs/master/fixed/20191124_fixed_cloud_layer_float.md
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index 2aa393f54..c9d53cbe4 100644
--- a/changelogs/master/fixed/20191124_fixed_cloud_layer_float.md
+++ b/changelogs/0.4.0/fixed/20191124_fixed_cloud_layer_float.md
@@ -1,2 +1,2 @@
* Fixed `CloudLayer.draw_on_image()` producing tuples instead of arrays
- as output for `float` input images.
\ No newline at end of file
+ as output for `float` input images. #540
\ No newline at end of file
diff --git a/changelogs/master/fixed/20191128_fixed_affine_translate.md b/changelogs/0.4.0/fixed/20191128_fixed_affine_translate.md
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diff --git a/changelogs/master/fixed/20191003_fixed_typo.md b/changelogs/master/fixed/20191003_fixed_typo.md
deleted file mode 100644
index fdcd9547e..000000000
--- a/changelogs/master/fixed/20191003_fixed_typo.md
+++ /dev/null
@@ -1 +0,0 @@
-* Fixed typo in image normalization.
diff --git a/changelogs/v0.4.0.summary.md b/changelogs/v0.4.0.summary.md
new file mode 100644
index 000000000..dc55fdcfd
--- /dev/null
+++ b/changelogs/v0.4.0.summary.md
@@ -0,0 +1,1865 @@
+# Table of Contents
+
+1. [Overview](#overview)
+2. [Example Images](#example_images)
+3. [Mixed-Category Patches](#mixed_category_patches)
+4. [Added](#added)
+5. [Changed](#changed)
+6. [Refactored](#refactored)
+7. [Fixed](#fixed)
+
+
+
+
+# Overview
+
+Release `0.4.0` focused mainly on adding new augmenters and improving
+the internal augmentation "backend".
+
+The following augmenters were added (see the
+[overview](https://imgaug.readthedocs.io/en/latest/source/overview_of_augmenters.html)
+docs for more details):
+* `ChangeColorTemperature`: Gives images a red, orange or blue touch.
+* New Brightness augmenters: `WithBrightnessChannels`,
+ `MultiplyAndAddToBrightness`, `MultiplyBrightness`, `AddToBrightness`.
+* New Dropout augmenters: `Dropout2d`, `TotalDropout`.
+* `RemoveSaturation`: Decreases the saturation of colors. Effects are similar
+ to `Grayscale`.
+* `Cartoon`: Applies a cartoon-style to images (classical / not-learned).
+* `MeanShiftBlur`: Blurs images using a mean-shift clustering method.
+ (Note: Very slow.)
+* `Jigsaw`: Splits the image into rectangular cells and randomly switches
+ some pairs of neighbouring cells. (Note: Does not support bounding boxes,
+ polygons and line strings.)
+* `WithPolarWarping`: Transforms images to polar coordinate space and applies
+ child augmenters there.
+* `SaveDebugImageEveryNBatches`: Generates and saves at every `N`-th batch a
+ debug image visualizing all inputs within the batch. Useful to gauge
+ strength and effects of augmentations and quickly spot errors in ground truth
+ data (e.g. misaligned bounding boxes).
+* `Cutout`: Removes rectangular subregions of images. Has some similarity with
+ `CoarseDropout`.
+* `Rain` and `RainLayer`: Adds rain-like effects to images.
+* `RandAugment`: Combination of multiple augmenters. Similar to the paper
+ description. (Note: Can currently only augment images.)
+* `Identity`: Same as `Noop`. Does nothing.
+* `UniformColorQuantizationToNBits`: Quantizes each image array component down
+ to `N` bits. Similar to `UniformColorQuantization`. Has the alias
+ `Posterize`.
+* `Solarize`: Invert with threshold.
+* `RemoveCBAsByOutOfImageFraction`, `ClipCBAsToImagePlanes`: Augmenters to
+ remove or clip coordinate-based augmentables, e.g. bounding boxes
+* More blend augmenters:
+ * `BlendAlphaMask`: Uses batch-wise generated masks for alpha-blending.
+ * `BlendAlphaSomeColors`: Alpha-blends only within image regions having
+ specific randomly chosen colors.
+ * `BlendAlphaSegMapClassIds`: Alpha-blends only within image regions having
+ specific class ids in segmentation maps.
+ * `BlendAlphaBoundingBoxes`: Alpha-blends only within image regions covered
+ by bounding boxes having specific labels.
+ * `BlendAlphaHorizontalLinearGradient`: Alpha-blends using horizontal
+ linear gradients.
+ * `BlendAlphaVerticalLinearGradient`: Analogous.
+ * `BlendAlphaRegularGrid`: Places a regular grid on each image and
+ samples one alpha value per grid cell. Can be used e.g. to achieve
+ coarse dropout.
+ * `BlendAlphaCheckerboard`: Places also a regular grid on each image,
+ but neighbouring cells use alpha values that are inverse to each other.
+* Shortcuts for `Affine`: `ScaleX`, `ScaleY`, `TranslateX`, `TranslateY`,
+ `Rotate`, `ShearX`, `ShearY`.
+* Several new crop and pad augmenters: `CenterCropToFixedSize`,
+ `CenterPadToFixedSize`, `CropToMultiplesOf`, `CenterCropToMultiplesOf`,
+ `PadToMultiplesOf`, `CenterPadToMultiplesOf`, `CropToPowersOf`,
+ `CenterCropToPowersOf`, `PadToPowersOf`, `CenterPadToPowersOf`,
+ `CropToAspectRatio`, `CenterCropToAspectRatio`, `PadToAspectRatio`,
+ `CenterPadToAspectRatio`, `PadToSquare`, `CenterPadToSquare`,
+ `CropToSquare`, `CenterCropToSquare`.
+* Wrappers around `imagecorruptions` package (verified to have identical
+ outputs):
+ `GaussianNoise`, `ShotNoise`, `ImpulseNoise`, `SpeckleNoise`,
+ `GaussianBlur`, `GlassBlur`, `DefocusBlur`, `MotionBlur`, `ZoomBlur`,
+ `Fog`, `Frost`, `Snow`, `Spatter`, `Contrast`, `Brightness`, `Saturate`,
+ `JpegCompression`, `Pixelate`, `ElasticTransform`.
+ The augmenters are accessible via `iaa.imgcorruptlike.`.
+* Wrappers around `PIL` functions (verified to have identical outputs):
+ `Solarize`, `Posterize`, `Equalize`, `Autocontrast`, `EnhanceColor`,
+ `EnhanceContrast`, `EnhanceBrightness`, `EnhanceSharpness`, `FilterBlur`,
+ `FilterSmooth`, `FilterSmoothMore`, `FilterEdgeEnhance`,
+ `FilterEdgeEnhanceMore` `FilterFindEdges`, `FilterContour`,
+ `FilterEmboss`, `FilterSharpen`, `FilterDetail`, `Affine`.
+ The augmenters are accessible via `iaa.pillike.`.
+
+Aside from these new augmenters, the following major changes were made:
+* Bounding boxes and line strings have now native augmentation methods.
+ Previously, they were converted to keypoints at the start of the
+ augmentation, which meant that child augmenters were unable to use
+ augmentation routines geared towards these two input types as they would
+ merely see a bunch of keypoints.
+* Augmentation happens now batchwise. Previously it was done
+ input type-wise. This change should improve performance for batches with
+ different types of inputs by re-using computation results for multiple
+ inputs. It also makes the library more flexible.
+* Improved the default parameters of augmenters. Most of them will now
+ produce medium-strength augmentations when instantiated without and
+ parameters. E.g. `CoarseDropout()` will now produce decent augmentations
+ instead of doing nothing. When using default parameters,
+ `Fliplr()` and `Flipud()` will always flip (p=100%).
+ `TotalDropout()` will always drop everything (p=100%).
+ `Grayscale()` and `RemoveSaturation()` will always fully grayscale/desaturate.
+ `Rot90()` will always rotate once (clockwise). `Invert()` will always
+ invert all components (p=100%).
+* Reworked the standard parameters shared by all augmenters.
+ `random_state` was renamed to `seed`, e.g. `Affine(..., seed=1)`
+ is now valid. The parameter `deterministic` is now deprecated.
+* Many methods were added to augmentables, e.g. `BoundingBoxesOnImage`
+ now supports index-based access (`bbs[0]` instead
+ of `bbs.bounding_boxes[0]`).
+* The bounding box drawing methods now also draw each BB's label.
+* All augmenters are now tested to be pickle-able without errors.
+* The library is now compatible with numpy 1.18 and python 3.8.
+* This release fixes two significant bugs in `Affine` that could lead
+ to unaligned outputs. It also fixes significant bugs related to
+ bounding box augmentation and various other issues. The update
+ is recommended. There are now around 5000 unique tests.
+
+
+
+
+# Example Images
+
+## Brightness
+
+Three new brightness-related augmenters are introduced. The example below
+shows `AddToBrightness`. First image is the input, the others show
+`AddToBrightness(-100)` to `AddToBrightness(100)`.
+
+
+
+
+## Cartoon
+
+A new cartoon style filter is introduced, shown below. Each row starts with
+the input image.
+
+
+
+
+## ChangeColorTemperature
+
+The color temperature of images can now be modified. The example below
+shows `ChangeColorTemperature(kelvin=1000)` to
+`ChangeColorTemperature(kelvin=5000)`, with the first image being the input.
+
+
+
+
+## Cutout
+
+Cutout is added to the library. The first row shows the hyperparameters that
+were used in the corresponding paper. The second row shows two cutout
+iterations per image, using intensity values, random RGB values and gaussian
+noise to fill in the pixels. First image in each row is the input.
+
+
+
+
+## Dropout2d and TotalDropout
+
+Two new dropout augmenters, `Dropout2d` and `TotalDropout`, are added.
+The example below shows `Dropout2d`. First image is the input.
+
+
+
+
+## Jigsaw
+
+A jigsaw puzzle augmenter is added. The first row below shows its effects
+using a grid size of `5x5`. The second row shows `10x10`.
+First image in each row is the input.
+
+
+
+
+## MeanShiftBlur
+
+A mean shift-based blur augmenter is added. First image below shows the input,
+followed by `MeanShiftBlur(5.0)` to `MeanShiftBlur(40.0)`.
+
+
+
+
+## Posterize
+
+The example below shows `Posterize` (aka `UniformQuantizationToNBits`)
+with `n_bits=8` to `n_bits=1`. First image is the input.
+
+
+
+
+## Solarize
+
+The example below shows `Solarize`, which is the same as `Invert` with a
+threshold. First image is the input.
+
+
+
+
+## Rain
+
+The example below shows the new `Rain` augmenter. First image is the input.
+
+
+
+
+## RandAugment
+
+This release adds an implementation of `RandAugment` the following example
+shows `RandAugment(n=2, m=20)`. First image is the input.
+
+
+
+
+## WithPolarWarping
+
+The example below shows `WithPolarWarping()` in combination with
+`CropAndPad` (first row), `Affine` (second row) and
+`AveragePooling` (third row). First image in each row is the input.
+
+
+
+The augmenter supports all input types, but bounding boxes and polygons
+should be used with caution. (Bounding boxes, because they tend to produce
+unintuitive results in combination with rotation-like augmentations.
+Polygons, because they can become invalid under geometric augmentations
+and will have to be repaired, which can easily mess them up.)
+
+
+## imagecorruptions wrappers
+
+Wrappers around the library `imagecorruptions` are added, which contains
+augmentation methods introduced by `Hendrycks and Dietterich - Benchmarking
+Neural Network Robustness to Common Corruptions and Surface Variations`.
+The methods were used in some recent papers. The example below shows their
+effects, always with `severity=3`.
+
+
+
+
+## PIL wrappers
+
+Various wrappers around popular `PIL` methods are added.
+The image below shows in the first row `Autocontrast`, in the second
+`EnhanceColor` (strength of `0.1` to `1.9`), the third
+`EnhanceSharpness` (strength of `0.1` to `1.9`), the fourth shows
+various convolution-based filters (`FilterBlur`, `FilterSmooth`,
+`FilterEdgeEnhance`, `FilterFindEdges`, `FilterContour`, `FilterSharpen`,
+`FilterDetail` -- in that order) and the fourth row shows `pillike.Affine`
+with the top-left as the transformation origin.
+The first image in each row is the input.
+
+
+
+
+## More Blending Augmenters
+
+Various new (alpha-)blending augmenters are introduced in this patch.
+
+The following example makes use of a segmentation map in which all cars
+are marked with a segmentation class id.
+It uses roughly
+`BlendAlphaSegMapClassIds(BlendAlphaSomeColors(AddToHueAndSaturation(...)))`
+in order to modify some colors within the car classes.
+Left is the input image, right is the output:
+
+
+ 
+ 
+
+
+Note that `BlendAlphaSegMapClassIds` must be called with all inputs
+at the same time, e.g. via `augmenters(images=..., segmentation_maps...)`.
+
+This example changes the train color using
+`BlendAlphaSegMapClassIds(AddToHueAndSaturation(...))`. The train has a
+separate class in the segmentation map.
+
+
+
+The next example applies blending to some non color-based augmenters. It uses
+roughly `BlendAlphaSegMapClassIds(AdditiveGaussianNoise(...))` (left)
+and `BlendAlphaSegMapClassIds(Emboss(...))` (right). The street has a separate
+class in the segmentation map.
+
+
+ 
+ 
+
+
+This example shows how blending can be used to achieve dropout effects.
+It uses roughly `BlendAlphaRegularGrid(Multiply(0.0))` (left) and
+`BlendAlphaCheckerboard(Multiply(0.0))` (right).
+
+
+ 
+ 
+
+
+This example shows `BlendAlphaSomeColors(RemoveSaturation(1.0))`, applied
+to a more colorful image:
+
+
+
+This release also adds `BlendAlphaBoundingBoxes`,
+`BlendAlphaHorizontalLinearGradient` and
+`BlendAlphaVerticalLinearGradient`. These are not visualized here.
+
+
+## SaveDebugImageEveryNBatches
+
+A new debug helper -- `SaveDebugImageEveryNBatches` -- was added.
+The example below shows one of its outputs for a batch containing images,
+segmentation maps and bounding boxes.
+
+
+
+Note that this augmenter must be called with all inputs at the same time,
+e.g. via `augmenters(images=..., segmentation_maps...)` for image + segmap
+inputs.
+
+
+
+
+# Mixed-Category Patches
+
+## Reworked Augmentation Methods [#451](https://github.com/aleju/imgaug/pull/451) [#566](https://github.com/aleju/imgaug/pull/566)
+
+The internal backend of the library was changed so that augmentation now
+happens batchwise instead of input-type-wise. Child augmenters still have
+the option of using input-type-wise augmentation. All calls are now at some
+point routed through `Augmenter.augment_batch_()` and child augmenters are
+expected to implement `_augment_batch_()`. This change allows to re-use
+information between different input types within the same batch, which in
+turn improves performance and extends the space of possible augmentations.
+
+Note: It is now recommended to use a batch-wise augmentation call. I.e.
+use `.augment_batch_()` or `.augment()` or `.__call__()`. These calls provide
+all inputs of a batch at the same time and several of the new augmenters now
+explicitly require that (e.g. `BlendAlphaBoundingBoxes`). Example:
+```python
+import numpy as np
+import imgaug as ia
+import imgaug.augmenters as iaa
+
+images = [np.zeros((32, 32, 3), dtype=np.uint8),
+ np.zeros((64, 64, 3), dtype=np.uint8)]
+bbs = [
+ [ia.BoundingBox(x1=0, y1=1, x2=2, y2=3)],
+ [ia.BoundingBox(x1=1, y1=2, x2=3, y2=4),
+ ia.BoundingBox(x1=2, y1=3, x2=4, y2=5)],
+]
+
+bbsois = [ia.BoundingBoxesOnImage(bbs[0], shape=images[0]),
+ ia.BoundingBoxesOnImage(bbs[1], shape=images[1])]
+
+aug = iaa.Affine(rotate=(-30, 30))
+
+# No longer recommended:
+aug_det = aug.to_deterministic()
+images_aug = aug_det.augment_images(images)
+bbsois_aug = aug_det.augment_bounding_boxes(bbsois)
+
+# Now recommended:
+images_aug, bbs_aug = aug(images=images, bounding_boxes=bbs)
+
+```
+
+* Added methods:
+ * `augmentables.batches.Batch.to_normalized_batch()`.
+ * `augmentables.batches.Batch.get_augmentables()`.
+ * `augmentables.batches.UnnormalizedBatch.get_augmentables()`.
+ * `augmentables.batches.Batch.get_augmentable_names()`.
+ * `augmentables.batches.UnnormalizedBatch.get_augmentable_names()`.
+ * `augmentables.batches.Batch.to_batch_in_augmentation()`.
+ * `augmentables.batches.Batch.fill_from_batch_in_augmentation_()`.
+ * `augmentables.batches.UnnormalizedBatch.fill_from_augmented_normalized_batch()`.
+ * `augmenters.meta.Augmenter.augment_batch_()`, ,
+ similar to `augment_batch()`, but explicitly works in-place and has a
+ `parent` parameter.
+ * `augmenters.meta.Augmenter._augment_batch_()`.
+ * `augmentables.polys.recover_psois_()`.
+ * `augmentables.utils.convert_cbaois_to_kpsois()`.
+ * `augmentables.utils.invert_convert_cbaois_to_kpsois_()`.
+ * `augmentables.utils.deepcopy_fast()`.
+ * `augmentables.bbs.BoundingBox.from_point_soup()`.
+ * `augmentables.bbs.BoundingBoxesOnImages.from_point_soups()`.
+ * Added method `to_xy_array()` to:
+ * `augmentables.bbs.BoundingBoxesOnImage`.
+ * `augmentables.polys.PolygonsOnImage`.
+ * `augmentables.lines.LineStringsOnImage`.
+ * Added methods `to_keypoints_on_image()`,
+ `invert_to_keypoints_on_image_()` and `fill_from_xy_array_()` to:
+ * `augmentables.kps.KeypointsOnImage`.
+ * `augmentables.bbs.BoundingBoxesOnImage`.
+ * `augmentables.polys.PolygonsOnImage`.
+ * `augmentables.lines.LineStringsOnImage`.
+
+* Added classes:
+ * `testutils.TemporaryDirectory` (context)
+
+* Changed:
+ * Changed the following methods to be thin wrappers around
+ `augment_batch_()`:
+ * `augmenters.meta.Augmenter.augment_images()`
+ * `augmenters.meta.Augmenter.augment_heatmaps()`.
+ * `augmenters.meta.Augmenter.augment_segmentation_maps()`.
+ * `augmenters.meta.Augmenter.augment_keypoints()`.
+ * `augmenters.meta.Augmenter.augment_bounding_boxes()`.
+ * `augmenters.meta.Augmenter.augment_polygons()`.
+ * `augmenters.meta.Augmenter.augment_line_strings()`.
+ * Changed `augment_image()`, `augment_images()`, `augment_heatmaps()`,
+ `augment_segmentation_maps()`, `augment_keypoints()`,
+ `augment_bounding_boxes()`, `augment_polygons()` and
+ `augment_line_strings()` to return `None` inputs without change.
+ Previously they resulted in an exception. This is more consistent with
+ the behaviour in the other `augment_*` methods.
+ * Changed `augment_images()` to no longer be abstract. It defaults
+ to not changing the input images.
+ * Changed `imgaug.augmentables.BoundingBoxesOnImage.from_xyxy_array()`
+ to also accept `(N, 2, 2)` arrays instead of only `(N, 4)`.
+
+Deprecated:
+ * Deprecated `imgaug.augmenters.meta.Augmenter.augment_batch()`.
+ Use `.augment_batch_()` instead.
+
+Refactored:
+ * Refactored most augmenters to use single `_augment_batch_()` method.
+
+Other changes:
+ * Added validation of input arguments to `KeypointsOnImage.from_xy_array()`.
+ * Improved validation of input arguments to
+ `BoundingBoxesOnImage.from_xyxy_array()`.
+
+
+## Reworked Quantization [#467](https://github.com/aleju/imgaug/pull/467)
+
+This patch reworked the quantization routines to also support quantization
+to `N` bits instead of `N` colors in a way that is similar to posterization
+in `PIL`. The patch added corresponding `UniformColorQuantizationToNBits`
+and `Posterize` augmenters, as well as a `quantize_uniform_to_n_bits()`
+function.
+
+* Added classes:
+ * `augmenters.color.UniformColorQuantizationToNBits`.
+ * `augmenters.color.Posterize` (alias of `UniformColorQuantizationToNBits`).
+
+* Added functions:
+ * `augmenters.color.quantize_uniform_()`, the in-place
+ version of `quantize_uniform()`.
+ * `augmenters.color.quantize_uniform_to_n_bits()`.
+ * `augmenters.color.quantize_uniform_to_n_bits_()`.
+ * `augmenters.color.posterize()`, an alias of
+ `quantize_uniform_to_n_bits()` that produces the same outputs as
+ `PIL.ImageOps.posterize()`.
+
+* Added parameters:
+ * Added `to_bin_centers=True` to `quantize_uniform()`, controling
+ whether each bin `(a, b)` should be quantized to `a + (b-a)/2` or `a`.
+
+* Deprecated:
+ * Renamed `imgaug.augmenters.color.quantize_colors_uniform(image, n_colors)`
+ to `imgaug.augmenters.color.quantize_uniform(arr, nb_bins)`. The old name
+ is now deprecated.
+ * Renamed `imgaug.augmenters.color.quantize_colors_kmeans(image, n_colors)`
+ to `imgaug.augmenters.color.quantize_kmeans(arr, nb_clusters)`. The old
+ name is now deprecated.
+
+* Other changes:
+ * Improved performance of `quantize_uniform()` by roughly 10x (small images
+ around 64x64) to 100x (large images around 1024x1024). This also affects
+ `UniformColorQuantization`.
+ * Improved performance of `UniformColorQuantization` by using more in-place
+ functions.
+
+* Fixed:
+ * Fixed `quantize_uniform()` producing wrong outputs for non-contiguous
+ arrays.
+
+
+## Improved Invert [#469](https://github.com/aleju/imgaug/pull/469)
+
+Added thresholds to `Invert` and the corresponding functions. This enables
+solarization (inversion with thresholds). The patch also added
+a corresponding `Solarize` augmenter and two solarization functions.
+
+* Added augmenter `imgaug.augmenters.Solarize`, a wrapper around `Invert`.
+* Added function `imgaug.augmenters.arithmetic.solarize()`, a wrapper around
+ `solarize_()`.
+* Added function `imgaug.augmenters.arithmetic.solarize_()`, a wrapper around
+ `invert_()`.
+* Added function `imgaug.augmenters.arithmetic.invert_()`, an in-place version
+ of `imgaug.augmenters.arithmetic.invert()`.
+* Added parameters `threshold` and `invert_above_threshold` to
+ `imgaug.augmenters.arithmetic.invert()`
+* Added parameters `threshold` and `invert_above_threshold` to
+ `imgaug.augmenters.arithmetic.Invert`.
+* Improved performance of `imgaug.augmenters.arithmetic.invert()` and
+ `imgaug.augmenters.arithmetic.Invert` for `uint8` images.
+
+
+## All Augmenters are now Pickle-able [#493](https://github.com/aleju/imgaug/pull/493) [#575](https://github.com/aleju/imgaug/pull/575)
+
+Ensured that all augmenters can be pickled and un-pickled without errors.
+
+* Added function `imgaug.testutils.runtest_pickleable_uint8_img()`.
+* Fixed `imgaug.augmenters.blur.MotionBlur` not being pickle-able.
+* Fixed `imgaug.augmenters.meta.AssertLambda` not being pickle-able.
+* Fixed `imgaug.augmenters.meta.AssertShape` not being pickle-able.
+* Fixed `imgaug.augmenters.color.MultiplyHueAndSaturation` not supporting
+ all standard RNG datatypes for `random_state`.
+
+
+## Extended Cropping and Padding Augmenters [#459](https://github.com/aleju/imgaug/pull/459)
+
+This patch extended the cropping and padding augmenters. It added
+augmenters that crop/pad towards multiples of values (e.g. crop the
+width until it is a multiple of `2`), towards powers of values (e.g.
+crop the width until it is one of `1, 2, 4, 8, 16, ...`), towards
+an aspect ratio (crop the width or height until `width/height = 2.0`) or
+towards a squared size (e.g. crop the width or height until they are equal).
+These augmenters are wrappers around `CropToFixedSize` and
+`PadToFixedSize`. All `*FixedSize` augmenters also have now corresponding
+`Center*ToFixedSize` aliases, e.g. `CenterCropToPowersOf`. These
+are equivalent to using `position="center"`, e.g. `CenterCropToPowersOf`
+is equivalent to `CropToPowersOf(..., position="center")`.
+
+The following functions were moved. Their old names are now deprecated.
+* Moved `imgaug.imgaug.pad` to `imgaug.augmenters.size.pad`
+* Moved `imgaug.imgaug.pad_to_aspect_ratio` to
+ `imgaug.augmenters.size.pad_to_aspect_ratio`.
+* Moved `imgaug.imgaug.pad_to_multiples_of` to
+ `imgaug.augmenters.size.pad_to_multiples_of`.
+* Moved `imgaug.imgaug.compute_paddings_for_aspect_ratio` to
+ `imgaug.augmenters.size.compute_paddings_to_reach_aspect_ratio`.
+* Moved `imgaug.imgaug.compute_paddings_to_reach_multiples_of`
+ to `imgaug.augmenters.size.compute_paddings_to_reach_multiples_of`.
+
+
+The following augmenters were added:
+* Added augmenter `CenterCropToFixedSize`.
+* Added augmenter `CenterPadToFixedSize`.
+* Added augmenter `CropToMultiplesOf`.
+* Added augmenter `CenterCropToMultiplesOf`.
+* Added augmenter `PadToMultiplesOf`.
+* Added augmenter `CenterPadToMultiplesOf`.
+* Added augmenter `CropToPowersOf`.
+* Added augmenter `CenterCropToPowersOf`.
+* Added augmenter `PadToPowersOf`.
+* Added augmenter `CenterPadToPowersOf`.
+* Added augmenter `CropToAspectRatio`.
+* Added augmenter `CenterCropToAspectRatio`.
+* Added augmenter `PadToAspectRatio`.
+* Added augmenter `CenterPadToAspectRatio`.
+* Added augmenter `PadToSquare`.
+* Added augmenter `CenterPadToSquare`.
+* Added augmenter `CropToSquare`.
+* Added augmenter `CenterCropToSquare`.
+
+All `Center` augmenters are wrappers around `` with parameter
+`position="center"`.
+
+
+Added functions:
+* Added function
+ `imgaug.augmenters.size.compute_croppings_to_reach_aspect_ratio()`.
+* Added function
+ `imgaug.augmenters.size.compute_croppings_to_reach_multiples_of()`.
+* Added function
+ `imgaug.augmenters.size.compute_croppings_to_reach_powers_of()`.
+* Added function
+ `imgaug.augmenters.size.compute_paddings_to_reach_powers_of()`.
+
+
+Other changes:
+* Extended augmenter `CropToFixedSize` to support `height` and/or `width`
+ parameters to be `None`, in which case the respective axis is not changed.
+* Extended augmenter `PadToFixedSize` to support `height` and/or `width`
+ parameters to be `None`, in which case the respective axis is not changed.
+* [rarely breaking] Changed `CropToFixedSize.get_parameters()` to also
+ return the `height` and `width` values.
+* [rarely breaking] Changed `PadToFixedSize.get_parameters()` to also
+ return the `height` and `width` values.
+* [rarely breaking] Changed the order of parameters returned by
+ `PadToFixedSize.get_parameters()` to match the order in
+ `PadToFixedSize.__init__()`
+* Changed `PadToFixedSize` to prefer padding the right side over the left side
+ and the bottom side over the top side. E.g. if using a center pad and
+ `3` columns have to be padded, it will pad `1` on the left and `2` on the
+ right. Previously it was the other way round. This was changed to establish
+ more consistency with the various other pad and crop methods.
+* Changed the projection of pad/crop values between images and non-images
+ to make the behaviour slightly more accurate in fringe cases.
+* Improved behaviour of function
+ `imgaug.augmenters.size.compute_paddings_for_aspect_ratio()` for zero-sized
+ axes.
+* Changed function `imgaug.augmenters.size.compute_paddings_for_aspect_ratio()`
+ to also support shape tuples instead of only ndarrays.
+* Changed function
+ `imgaug.augmenters.size.compute_paddings_to_reach_multiples_of()`
+ to also support shape tuples instead of only ndarrays.
+
+
+Fixes:
+* Fixed a formatting error in an error message of
+ `compute_paddings_to_reach_multiples_of()`.
+
+
+## More Choices for Image Blending [#462](https://github.com/aleju/imgaug/pull/462) [#556](https://github.com/aleju/imgaug/pull/556)
+
+The available augmenters for alpha-blending of images were
+significantly extended. There are now new blending
+augmenters available to alpha-blend acoording to:
+* Some randomly chosen colors. (`BlendAlphaSomeColors`)
+* Linear gradients. (`BlendAlphaHorizontalLinearGradient`,
+ `BlendAlphaVerticalLinearGradient`)
+* Regular grids and checkerboard patterns. (`BlendAlphaRegularGrid`,
+ `BlendAlphaCheckerboard`)
+* Only at locations that overlap with specific segmentation class
+ IDs (or the inverse of that). (`BlendAlphaSegMapClassIds`)
+* Only within bounding boxes with specific labels (or the inverse
+ of that). (`BlendAlphaBoundingBoxes`)
+
+This allows to e.g. randomly remove some colors while leaving
+other colors unchanged (`BlendAlphaSomeColors(Grayscale(1.0))`),
+to change the color of some objects
+(`BlendAlphaSegMapClassIds(AddToHue((-256, 256)))`), to add
+cloud-patterns only to the top of images
+(`BlendAlphaVerticalLinearGradient(Clouds())`) or to apply
+augmenters in some coarse rectangular areas (e.g.
+`BlendAlphaRegularGrid(Multiply(0.0))` to achieve a similar
+effect to `CoarseDropout` or
+`BlendAlphaRegularGrid(AveragePooling(8))` to pool in equally
+coarse image sub-regions).
+
+Other mask-based alpha blending techniques can be achieved by
+subclassing `IBatchwiseMaskGenerator` and providing an
+instance of such a class to `BlendAlphaMask`.
+
+This patch also changes the naming of the blending augmenters
+as follows:
+* `Alpha` -> `BlendAlpha`
+* `AlphaElementwise` -> `BlendAlphaElementwise`
+* `SimplexNoiseAlpha` -> `BlendAlphaSimplexNoise`
+* `FrequencyNoiseAlpha` -> `BlendAlphaFrequencyNoise`
+The old names are now deprecated.
+Furthermore, the parameters `first` and `second`, which were
+used by all blending augmenters, have now the names `foreground`
+and `background`.
+
+List of changes:
+* Added `imgaug.augmenters.blend.BlendAlphaMask`, which uses
+ a mask generator instance to generate per batch alpha masks and
+ then alpha-blends using these masks.
+* Added `imgaug.augmenters.blend.BlendAlphaSomeColors`.
+* Added `imgaug.augmenters.blend.BlendAlphaHorizontalLinearGradient`.
+* Added `imgaug.augmenters.blend.BlendAlphaVerticalLinearGradient`.
+* Added `imgaug.augmenters.blend.BlendAlphaRegularGrid`.
+* Added `imgaug.augmenters.blend.BlendAlphaCheckerboard`.
+* Added `imgaug.augmenters.blend.BlendAlphaSegMapClassIds`.
+* Added `imgaug.augmenters.blend.BlendAlphaBoundingBoxes`.
+* Added `imgaug.augmenters.blend.IBatchwiseMaskGenerator`,
+ an interface for classes generating masks on a batch-by-batch
+ basis.
+* Added `imgaug.augmenters.blend.StochasticParameterMaskGen`,
+ a helper to generate masks from `StochasticParameter` instances.
+* Added `imgaug.augmenters.blend.SomeColorsMaskGen`, a generator
+ that produces masks marking randomly chosen colors in images.
+* Added `imgaug.augmenters.blend.HorizontalLinearGradientMaskGen`,
+ a linear gradient mask generator.
+* Added `imgaug.augmenters.blend.VerticalLinearGradientMaskGen`,
+ a linear gradient mask generator.
+* Added `imgaug.augmenters.blend.RegularGridMaskGen`,
+ a checkerboard-like mask generator where every grid cell has
+ a random alpha value.
+* Added `imgaug.augmenters.blend.CheckerboardMaskGen`,
+ a checkerboard-like mask generator where every grid cell has
+ the opposite alpha value of its 4-neighbours.
+* Added `imgaug.augmenters.blend.SegMapClassIdsMaskGen`, a
+ segmentation map-based mask generator.
+* Added `imgaug.augmenters.blend.BoundingBoxesMaskGen`, a bounding
+ box-based mask generator.
+* Added `imgaug.augmenters.blend.InvertMaskGen`, an mask generator
+ that inverts masks produces by child generators.
+* Changed `imgaug.parameters.SimplexNoise` and
+ `imgaug.parameters.FrequencyNoise` to also accept `(H, W, C)`
+ sampling shapes, instead of only `(H, W)`.
+* Refactored `AlphaElementwise` to be a wrapper around
+ `BlendAlphaMask`.
+* Renamed `Alpha` to `BlendAlpha`.
+ `Alpha` is now deprecated.
+* Renamed `AlphaElementwise` to `BlendAlphaElementwise`.
+ `AlphaElementwise` is now deprecated.
+* Renamed `SimplexNoiseAlpha` to `BlendAlphaSimplexNoise`.
+ `SimplexNoiseAlpha` is now deprecated.
+* Renamed `FrequencyNoiseAlpha` to `BlendAlphaFrequencyNoise`.
+ `FrequencyNoiseAlpha` is now deprecated.
+* Renamed arguments `first` and `second` to `foreground` and `background`
+ in `BlendAlpha`, `BlendAlphaElementwise`, `BlendAlphaSimplexNoise` and
+ `BlendAlphaFrequencyNoise`.
+* Changed `imgaug.parameters.handle_categorical_string_param()` to allow
+ parameter `valid_values` to be `None`.
+* Fixed a wrong error message in
+ `imgaug.augmenters.color.change_colorspace_()`.
+
+
+
+
+# Added
+
+## Unwrapped Bounding Box Augmentation [#446](https://github.com/aleju/imgaug/pull/446)
+
+The bounding box augmentation was previously a wrapper around keypoint
+augmentation. Bounding Boxes were simply converted to keypoints at the
+start of the augmentation and then augmented as keypoints by all called
+augmenters. This was now changed so that all augmenters receive
+bounding boxes and can then chose how to augment them. This enables
+augmentations specific to bounding boxes.
+
+* Added property `coords` to `BoundingBox`. The property returns an `(N,2)`
+ numpy array containing the coordinates of the top-left and bottom-right
+ bounding box corners.
+* Added method `BoundingBox.coords_almost_equals(other)`.
+* Added method `BoundingBox.almost_equals(other)`.
+* Changed method `Polygon.almost_equals(other)` to no longer verify the
+ datatype. It is assumed now that the input is a Polygon.
+* Added property `items` to `KeypointsOnImage`, `BoundingBoxesOnImage`,
+ `PolygonsOnImage`, `LineStringsOnImage`. The property returns the
+ keypoints/BBs/polygons/LineStrings contained by that instance.
+* Added method `Polygon.coords_almost_equals(other)`. Alias for
+ `Polygon.exterior_almost_equals(other)`.
+* Added property `Polygon.coords`. Alias for `Polygon.exterior`.
+* Added property `Keypoint.coords`.
+* Added method `Keypoint.coords_almost_equals(other)`.
+* Added method `Keypoint.almost_equals(other)`.
+* Added method `imgaug.testutils.assert_cbaois_equal()`.
+* Added method `imgaug.testutils.shift_cbaoi()`.
+* Added internal `_augment_bounding_boxes()` methods to various augmenters.
+ This allows to individually control how bounding boxes are supposed to
+ be augmented. Previously, the bounding box augmentation was a wrapper around
+ keypoint augmentation that did not allow such control.
+* **[breaking]** Added parameter `parents` to
+ `Augmenter.augment_bounding_boxes()`.
+ This breaks if `hooks` was used as a *positional* argument in connection with
+ that method.
+* [rarely breaking] Added parameter `func_bounding_boxes` to `Lambda`.
+ This breaks if one relied on the order of the augmenter's parameters instead
+ of their names.
+* [rarely breaking] Added parameter `func_bounding_boxes` to `AssertLambda`.
+ This breaks if one relied on the order of the augmenter's parameters instead
+ of their names.
+* [rarely breaking] Added parameter `check_bounding_boxes` to `AssertShape`.
+ This breaks if one relied on the order of the augmenter's parameters instead
+ of their names.
+
+
+## Unwrapped Line String Augmentation [#450](https://github.com/aleju/imgaug/pull/450)
+
+This patch is the same as the bounding box unwrapping above, only applied to
+line strings.
+
+* Added internal `_augment_line_strings()` methods to various augmenters.
+ This allows to individually control how line strings are supposed to
+ be augmented. Previously, the line string augmentation was a wrapper around
+ keypoint augmentation that did not allow such control.
+* [rarely breaking] Added parameter `func_line_strings` to `Lambda`.
+ This breaks if one relied on the order of the augmenter's parameters instead
+ of their names.
+* [rarely breaking] Added parameter `func_line_strings` to `AssertLambda`.
+ This breaks if one relied on the order of the augmenter's parameters instead
+ of their names.
+* [rarely breaking] Added parameter `check_line_strings` to `AssertShape`.
+ This breaks if one relied on the order of the augmenter's parameters instead
+ of their names.
+
+
+## Added fit_output to PerspectiveTransform [#452](https://github.com/aleju/imgaug/pull/452) [#456](https://github.com/aleju/imgaug/pull/456)
+
+This patch added `fit_output` to `PerspectiveTransform`.
+
+* [rarely breaking] PerspectiveTransform has now a `fit_output` parameter,
+ similar to `Affine`. This change may break code that relied on the order of
+ arguments to `__init__`.
+* The sampling code of `PerspectiveTransform` was reworked and should now
+ be faster.
+
+
+# Added `ChangeColorTemperature` Augmenter [#454](https://github.com/aleju/imgaug/pull/454)
+
+This patch added an augmenter and corresponding function to change the
+color temperature of images. This adds e.g. red, orange or blue tints.
+
+* Added augmenter `imgaug.augmenters.color.ChangeColorTemperature`.
+* Added function `imgaug.augmenters.color.change_color_temperatures_()`.
+* Added function `imgaug.augmenters.color.change_color_temperature_()`.
+
+
+## Added Brightness Augmenters [#455](https://github.com/aleju/imgaug/pull/455)
+
+This patch added brightness-related augmenters. At the core is
+`WithBrightnessChannels`, which converts images to a choice of
+colorspaces that have brightness-related channels, extracts these
+channels and applies child augmenters to them. E.g. it might
+transform to `L*a*b*` colorspace and extract `L`, then apply
+a child augmenter and convert the modified `L*a*b*` back to `RGB`.
+
+* Added augmenter `imgaug.augmenters.color.WithBrightnessChannels`.
+* Added augmenter `imgaug.augmenters.color.MultiplyAndAddToBrightness`.
+* Added augmenter `imgaug.augmenters.color.MultiplyBrightness`.
+* Added augmenter `imgaug.augmenters.color.AddToBrightness`.
+* Added method `imgaug.parameters.handle_categorical_string_param()`.
+* Changed `change_colorspaces_()` to accept any iterable of `str` for
+ argument `to_colorspaces`, not just `list`.
+
+
+## Added More Dropout Augmenters [#458](https://github.com/aleju/imgaug/pull/458)
+
+This patch added more dropout augmenters. `Dropout2d` randomly zeros
+whole channels, while `TotalDropout` randomly zeros whole images.
+The latter augmenter can sometimes be used in connection with
+blending operations. (Note though that in these cases it should not be
+used with coordinate-based input data, such as bounding boxes, because
+it removes that data from examples affected by total dropout. That
+breaks the blending operation, which requires the number of coordinates
+to be unchanged.)
+
+* Added a new augmenter `Dropout2d`, which drops channels in images with
+ a defineable probability `p`. Dropped channels will be filled with zeros.
+ By default, the augmenter keeps at least one channel in each image
+ unaltered (i.e. not dropped).
+* Added new augmenter `TotalDropout`, which sets all components to zero
+ for `p` percent of all images. The augmenter should be used in connection
+ with e.g. blend augmenters.
+
+
+## Added `RemoveSaturation` [#462](https://github.com/aleju/imgaug/pull/462)
+
+* Added `RemoveSaturation`, a shortcut for `MultiplySaturation((0.0, 1.0))`
+ with outputs similar to `Grayscale((0.0, 1.0))`.
+
+
+## Added `Cartoon` Augmenter [#463](https://github.com/aleju/imgaug/pull/463)
+
+This patch added a filter to change the style of images to one that looks
+more cartoon-ish. The filter used classical methods. As such it works well
+on some images and badly on others. It seems to work better on images
+that already have rather saturated colors and pronounced edges.
+
+* Added module `imgaug.augmenters.artistic`.
+* Added function `imgaug.augmenters.artistic.stylize_cartoon(image)`.
+* Added augmenter `imgaug.augmenters.artistic.Cartoon`.
+
+
+## Added `MeanShiftBlur` Augmenter [#466](https://github.com/aleju/imgaug/pull/466)
+
+This patch added a mean shift-based blur filter. Note that it is very
+slow when using the default parameters (high radius).
+
+* Added function `imgaug.augmenters.blur.blur_mean_shift_(image)`.
+* Added augmenter `imgaug.augmenters.blur.MeanShiftBlur`.
+
+
+## Added `DeterministicList` Parameter [#475](https://github.com/aleju/imgaug/pull/475)
+
+Added `imgaug.parameters.DeterministicList`. Upon a request to generate
+samples of shape `S`, this parameter will create a new array of shape `S`
+and fill it by cycling over its list of values repeatedly.
+
+
+## Added `Jigsaw` Augmenter [#476](https://github.com/aleju/imgaug/pull/476) [#577](https://github.com/aleju/imgaug/pull/577)
+
+This patch added a jigsaw puzzle augmenter and corresponding functions.
+The augmenter splits each image into a regular grid of cells, then
+randomly picks some cells and switches them with one of their
+8-neighbours. The process is repeated for `N` steps per image.
+
+Note: The augmenter will reject batches containing bounding boxes,
+polygons or line strings.
+
+* Added function `imgaug.augmenters.geometric.apply_jigsaw()`.
+* Added function `imgaug.augmenters.geometric.apply_jigsaw_to_coords()`.
+* Added function `imgaug.augmenters.geometric.generate_jigsaw_destinations()`.
+
+
+## Added Wrappers around Package `PIL` [#479](https://github.com/aleju/imgaug/pull/479) [#480](https://github.com/aleju/imgaug/pull/480) [#538](https://github.com/aleju/imgaug/pull/538)
+
+This patch added wrapper functions and augmenters around popular
+`PIL` functions. The outputs of these functions and augmenters are
+tested to be identical with the ones in `PIL`. They are intended
+for research cases where papers have to be re-implemented as
+accurately as possible.
+
+* Added module `imgaug.augmenters.pillike`, which contains augmenters and
+ functions corresponding to commonly used PIL functions. Their outputs
+ are guaranteed to be identical to the PIL outputs.
+* Added the following functions to the module:
+ * `imgaug.augmenters.pillike.equalize`
+ * `imgaug.augmenters.pillike.equalize_`
+ * `imgaug.augmenters.pillike.autocontrast`
+ * `imgaug.augmenters.pillike.autocontrast_`
+ * `imgaug.augmenters.pillike.solarize`
+ * `imgaug.augmenters.pillike.solarize_`
+ * `imgaug.augmenters.pillike.posterize`
+ * `imgaug.augmenters.pillike.posterize_`
+ * `imgaug.augmenters.pillike.enhance_color`
+ * `imgaug.augmenters.pillike.enhance_contrast`
+ * `imgaug.augmenters.pillike.enhance_brightness`
+ * `imgaug.augmenters.pillike.enhance_sharpness`
+ * `imgaug.augmenters.pillike.filter_blur`
+ * `imgaug.augmenters.pillike.filter_smooth`
+ * `imgaug.augmenters.pillike.filter_smooth_more`
+ * `imgaug.augmenters.pillike.filter_edge_enhance`
+ * `imgaug.augmenters.pillike.filter_edge_enhance_more`
+ * `imgaug.augmenters.pillike.filter_find_edges`
+ * `imgaug.augmenters.pillike.filter_contour`
+ * `imgaug.augmenters.pillike.filter_emboss`
+ * `imgaug.augmenters.pillike.filter_sharpen`
+ * `imgaug.augmenters.pillike.filter_detail`
+ * `imgaug.augmenters.pillike.warp_affine`
+* Added the following augmenters to the module:
+ * `imgaug.augmenters.pillike.Solarize`
+ * `imgaug.augmenters.pillike.Posterize`.
+ (Currently alias for `imgaug.augmenters.color.Posterize`.)
+ * `imgaug.augmenters.pillike.Equalize`
+ * `imgaug.augmenters.pillike.Autocontrast`
+ * `imgaug.augmenters.pillike.EnhanceColor`
+ * `imgaug.augmenters.pillike.EnhanceContrast`
+ * `imgaug.augmenters.pillike.EnhanceBrightness`
+ * `imgaug.augmenters.pillike.EnhanceSharpness`
+ * `imgaug.augmenters.pillike.FilterBlur`
+ * `imgaug.augmenters.pillike.FilterSmooth`
+ * `imgaug.augmenters.pillike.FilterSmoothMore`
+ * `imgaug.augmenters.pillike.FilterEdgeEnhance`
+ * `imgaug.augmenters.pillike.FilterEdgeEnhanceMore`
+ * `imgaug.augmenters.pillike.FilterFindEdges`
+ * `imgaug.augmenters.pillike.FilterContour`
+ * `imgaug.augmenters.pillike.FilterEmboss`
+ * `imgaug.augmenters.pillike.FilterSharpen`
+ * `imgaug.augmenters.pillike.FilterDetail`
+ * `imgaug.augmenters.pillike.Affine`
+
+
+## Added `Identity` [#481](https://github.com/aleju/imgaug/pull/481)
+
+This patch added an identity function augmenter (`Identity`), which is
+the same as `Noop` and will replace the latter one in the long run.
+
+* [rarely breaking] Added `imgaug.augmenters.meta.Identity`, an alias of
+ `Noop`. `Identity` is now the recommended augmenter for identity
+ transformations. This change can break code that explicitly relied on
+ exactly `Noop` being used, e.g. via `isinstance` checks.
+* Renamed parameter `noop_if_topmost` to `identity_if_topmost` in
+ method `imgaug.augmenters.meta.Augmenter.remove_augmenters()`. The old name
+ is now deprecated.
+
+
+## Added Shearing on the Y-Axis to `Affine` [#482](https://github.com/aleju/imgaug/pull/482)
+
+`Affine` was changed to now also support shearing on the y-axis.
+Previously, only the x-axis was supported. Use e.g.
+`Affine(shear={"y": (-20, 20))` now.
+
+* [rarely breaking] Extended `Affine` to also support shearing on the
+ y-axis (previously, only x-axis was possible). This feature can be used
+ via e.g. ``Affine(shear={"x": (-30, 30), "y": (-10, 10)})``. If instead
+ a single number is used (e.g. ``Affine(shear=15)``), shearing will be done
+ only on the x-axis. If a single ``tuple``, ``list`` or
+ ``StochasticParameter`` is used, the generated samples will be used
+ identically for both the x-axis and y-axis (this is consistent with
+ translation and scaling). To get independent random samples per axis use
+ the dictionary form.
+
+
+## Added Wrappers around `Affine` [#484](https://github.com/aleju/imgaug/pull/484)
+
+This patch added a few convenience wrappers around `Affine`.
+
+* Added `imgaug.augmenters.geometric.ScaleX`.
+* Added `imgaug.augmenters.geometric.ScaleY`.
+* Added `imgaug.augmenters.geometric.TranslateX`.
+* Added `imgaug.augmenters.geometric.TranslateY`.
+* Added `imgaug.augmenters.geometric.Rotate`.
+* Added `imgaug.augmenters.geometric.ShearX`.
+* Added `imgaug.augmenters.geometric.ShearY`.
+
+
+## Added More Methods to Remove Out-of-Image Augmentables [#487](https://github.com/aleju/imgaug/pull/487)
+
+This patch extended the methods to handle coordinate-based augmentables,
+e.g. bounding boxes, that are partially/fully outside of the image plane.
+They can now more easily be dropped if more than `p%` of their areas is
+outside of the image plane.
+
+The patch also adds augmenters to remove and clip coordinate-based
+augmentables that are outside of the image plane.
+
+* Added `Keypoint.is_out_of_image()`.
+
+* Added `BoundingBox.compute_out_of_image_area()`.
+* Added `Polygon.compute_out_of_image_area()`.
+
+* Added `Keypoint.compute_out_of_image_fraction()`
+* Added `BoundingBox.compute_out_of_image_fraction()`.
+* Added `Polygon.compute_out_of_image_fraction()`.
+* Added `LineString.compute_out_of_image_fraction()`.
+
+* Added `KeypointsOnImage.remove_out_of_image_fraction()`.
+* Added `BoundingBoxesOnImage.remove_out_of_image_fraction()`.
+* Added `PolygonsOnImage.remove_out_of_image_fraction()`.
+* Added `LineStringsOnImage.remove_out_of_image_fraction()`.
+
+* Added `KeypointsOnImage.clip_out_of_image()`.
+
+* Added `imgaug.augmenters.meta.RemoveCBAsByOutOfImageFraction`.
+ Removes coordinate-based augmentables (e.g. BBs) that have at least a
+ specified fraction of their area outside of the image plane.
+* Added `imgaug.augmenters.meta.ClipCBAsToImagePlanes`.
+ Clips off all parts from coordinate-based augmentables (e.g. BBs) that are
+ outside of the corresponding image.
+
+* Changed `Polygon.area` to return `0.0` if the polygon contains less than
+ three points (previously: exception).
+
+
+## Added Bounding Box to Polygon Conversion [#489](https://github.com/aleju/imgaug/pull/489)
+
+* Added method `imgaug.augmentables.bbs.BoundingBox.to_polygon()`.
+* Added method
+ `imgaug.augmentables.bbs.BoundingBoxesOnImage.to_polygons_on_image()`.
+
+
+## Added Polygon Subdivision [#489](https://github.com/aleju/imgaug/pull/489)
+
+* Added method `imgaug.augmentables.polys.Polygon.subdivide(N)`.
+ The method increases the polygon's corner point count by interpolating
+ `N` points on each edge with regular distance.
+* Added method `imgaug.augmentables.polys.PolygonsOnImage.subdivide(N)`.
+
+
+## Added `WithPolarWarping` Augmenter [#489](https://github.com/aleju/imgaug/pull/489)
+
+This patch added an augmenter to transform images to polar coordinates
+and apply child augmenters within that space. This leads to interesting
+effects in combination with augmenters that affect pixel locations, such
+as cropping or affine transformations.
+
+* Added augmenter `imgaug.augmenters.geometric.WithPolarWarping`, an
+ augmenter that applies child augmenters in a polar representation of the
+ image.
+
+
+## Added Convenient Access Methods to Coordinate-Based Augmentables [#495](https://github.com/aleju/imgaug/pull/495) [#541](https://github.com/aleju/imgaug/pull/541)
+
+This patch added various magic functions to coordinate-based
+augmentables that make their usage more convenient. Example:
+```python
+import imgaug as ia
+bb1 = ia.BoundingBox(x1=0, y1=1, x2=2, y2=3)
+bb2 = ia.BoundingBox(x1=1, y1=2, x2=3, y2=4)
+bbsoi = ia.BoundingBoxesOnImage([bb1, bb2])
+
+print(bbsoi[0]) # prints now str(bb1)
+print(len(bbsoi)) # prints now 2
+for bb in bbsoi: # looping is now supported
+ print(bb)
+```
+
+* Added module `imgaug.augmentables.base`.
+* Added interface `imgaug.augmentables.base.IAugmentable`, implemented by
+ `HeatmapsOnImage`, `SegmentationMapsOnImage`, `KeypointsOnImage`,
+ `BoundingBoxesOnImage`, `PolygonsOnImage` and `LineStringsOnImage`.
+* Added ability to iterate over coordinate-based `*OnImage` instances
+ (keypoints, bounding boxes, polygons, line strings), e.g.
+ `bbsoi = BoundingBoxesOnImage(bbs, shape=...); for bb in bbsoi: ...`.
+ would iterate now over `bbs`.
+* Added implementations of `__len__` methods to coordinate-based `*OnImage`
+ instances, e.g.
+ `bbsoi = BoundingBoxesOnImage(bbs, shape=...); print(len(bbsoi))`
+ would now print the number of bounding boxes in `bbsoi`.
+* Added ability to iterate over coordinates of `BoundingBox` (top-left,
+ bottom-right), `Polygon` and `LineString` via `for xy in obj: ...`.
+* Added ability to access coordinates of `BoundingBox`, `Polygon` and
+ `LineString` using indices or slices, e.g. `line_string[1:]` to get an
+ array of all coordinates except the first one.
+* Added property `Keypoint.xy`.
+* Added property `Keypoint.xy_int`.
+
+
+## Added `SaveDebugImageEveryNBatches` Augmenter [#502](https://github.com/aleju/imgaug/pull/502)
+
+This patch added a debug augmenter `SaveDebugImageEveryNBatches` that
+visualizes a whole batch and saves the corresponding image to a directory.
+The visualization happens at every `Nth` batch. The plot contains
+a visualization of all images within the batch, as well as all additional
+input data (e.g. segmentation maps or bounding boxes overlayed with
+images). The plot also contains various additional information, such as
+observed value ranges (min/max values) of images, observed labels of
+bounding boxes or observed segmentation classes.
+
+The augmenter can be used during training to evaluate the strength of
+augmentations, whether all data is still aligned (e.g. bounding box
+positions match object positions) and whether the data statistics match
+the expectations (e.g. no segmentation map classes missing).
+
+The augmenter might be useful even if no augmentation is actually performed.
+
+* Added module `imgaug.augmenters.debug`.
+* Added function `imgaug.augmenters.debug.draw_debug_image()`. The function
+ draws an image containing debugging information for a provided set of
+ images and non-image data (e.g. segmentation maps, bounding boxes)
+ corresponding to a single batch. The debug image visualizes these
+ informations (e.g. bounding boxes drawn on images) and offers relevant
+ information (e.g. actual value ranges of images, labels of bounding
+ boxes and their counts, etc.).
+* Added augmenter `imgaug.augmenters.debug.SaveDebugImageEveryNBatches`.
+ Augmenter corresponding to `draw_debug_image()`. Saves an image at every
+ n-th batch into a provided folder.
+
+
+## Added Multi-Channel cvals in `pad()` [#502](https://github.com/aleju/imgaug/pull/502)
+
+Improved `imgaug.augmenters.size.pad()` to support multi-channel values
+for the `cval` parameter (e.g. RGB colors).
+
+
+## Added Wrappers around Package `imagecorruptions` [#530](https://github.com/aleju/imgaug/pull/530)
+
+Added wrappers around the functions from package
+[bethgelab/imagecorruptions](https://github.com/bethgelab/imagecorruptions).
+The functions in that package were used in some recent papers and are added
+here for convenience.
+The wrappers produce arrays containing values identical to the output
+arrays from the corresponding `imagecorruptions` functions when called
+via the `imagecorruptions.corrupt()` (verified via unittests).
+The interfaces of the wrapper functions are identical to the
+`imagecorruptions` functions, with the only difference of also supporting
+`seed` parameters.
+
+* Added module `imgaug.augmenters.imgcorruptlike`. The `like` signals that
+ the augmentation functions do not *have* to wrap `imagecorruptions`
+ internally. They merely have to produce the same outputs.
+* Added the following functions to module `imgaug.augmenters.imgcorruptlike`:
+ * `apply_gaussian_noise()`
+ * `apply_shot_noise()`
+ * `apply_impulse_noise()`
+ * `apply_speckle_noise()`
+ * `apply_gaussian_blur()`
+ * `apply_glass_blur()` (improved performance over original function)
+ * `apply_defocus_blur()`
+ * `apply_motion_blur()`
+ * `apply_zoom_blur()`
+ * `apply_fog()`
+ * `apply_snow()`
+ * `apply_spatter()`
+ * `apply_contrast()`
+ * `apply_brightness()`
+ * `apply_saturate()`
+ * `apply_jpeg_compression()`
+ * `apply_pixelate()`
+ * `apply_elastic_transform()`
+* Added function
+ `imgaug.augmenters.imgcorruptlike.get_corruption_names(subset)`.
+ Similar to `imagecorruptions.get_corruption_names(subset)`, but returns a
+ tuple
+ `(list of corruption method names, list of corruption method functions)`,
+ instead of only the names.
+* Added the following augmenters to module `imgaug.augmenters.imgcorruptlike`:
+ * `GaussianNoise`
+ * `ShotNoise`
+ * `ImpulseNoise`
+ * `SpeckleNoise`
+ * `GaussianBlur`
+ * `GlassBlur`
+ * `DefocusBlur`
+ * `MotionBlur`
+ * `ZoomBlur`
+ * `Fog`
+ * `Frost`
+ * `Snow`
+ * `Spatter`
+ * `Contrast`
+ * `Brightness`
+ * `Saturate`
+ * `JpegCompression`
+ * `Pixelate`
+ * `ElasticTransform`
+* Added context `imgaug.random.temporary_numpy_seed()`.
+
+
+## Added `Cutout` Augmenter [#531](https://github.com/aleju/imgaug/pull/531) [#570](https://github.com/aleju/imgaug/pull/570)
+
+This patch added Cutout augmentation, similar to the paper proposal.
+The augmetner has some similarity with `CoarseDropout`.
+
+* Added `imgaug.augmenters.arithmetic.apply_cutout_()`, which replaces
+ in-place a single rectangular area with a constant intensity value or a
+ constant color or gaussian noise.
+ See also the [paper](https://arxiv.org/abs/1708.04552) about Cutout.
+* Added `imgaug.augmenters.arithmetic.apply_cutout()`. Same as
+ `apply_cutout_()`, but copies the input images before applying cutout.
+* Added `imgaug.augmenters.arithmetic.Cutout`.
+
+
+## Added in-place Methods for Coordinate-based Augmentables [#532](https://github.com/aleju/imgaug/pull/532)
+
+This patch added for many already existing methods corresponding in-place
+variations. They are now used throughout the library, improving the
+performance of augmentation in the case of e.g. bounding boxes.
+
+* Added `Keypoint.project_()`.
+* Added `Keypoint.shift_()`.
+* Added `KeypointsOnImage.on_()`.
+* Added setter for `KeypontsOnImage.items`.
+* Added setter for `BoundingBoxesOnImage.items`.
+* Added setter for `LineStringsOnImage.items`.
+* Added setter for `PolygonsOnImage.items`.
+* Added `KeypointsOnImage.remove_out_of_image_fraction_()`.
+* Added `KeypointsOnImage.clip_out_of_image_fraction_()`.
+* Added `KeypointsOnImage.shift_()`.
+* Added `BoundingBox.project_()`.
+* Added `BoundingBox.extend_()`.
+* Added `BoundingBox.clip_out_of_image_()`.
+* Added `BoundingBox.shift_()`.
+* Added `BoundingBoxesOnImage.on_()`.
+* Added `BoundingBoxesOnImage.clip_out_of_image_()`.
+* Added `BoundingBoxesOnImage.remove_out_of_image_()`.
+* Added `BoundingBoxesOnImage.remove_out_of_image_fraction_()`.
+* Added `BoundingBoxesOnImage.shift_()`.
+* Added `imgaug.augmentables.utils.project_coords_()`.
+* Added `LineString.project_()`.
+* Added `LineString.shift_()`.
+* Added `LineStringsOnImage.on_()`.
+* Added `LineStringsOnImage.remove_out_of_image_()`.
+* Added `LineStringsOnImage.remove_out_of_image_fraction_()`.
+* Added `LineStringsOnImage.clip_out_of_image_()`.
+* Added `LineStringsOnImage.shift_()`.
+* Added `Polygon.project_()`.
+* Added `Polygon.shift_()`.
+* Added `Polygon.on_()`.
+* Added `Polygon.subdivide_()`.
+* Added `PolygonsOnImage.remove_out_of_image_()`.
+* Added `PolygonsOnImage.remove_out_of_image_fraction_()`.
+* Added `PolygonsOnImage.clip_out_of_image_()`.
+* Added `PolygonsOnImage.shift_()`.
+* Added `PolygonsOnImage.subdivide_()`.
+* Switched `BoundingBoxesOnImage.copy()` to a custom copy operation (away
+ from module `copy` module).
+* Added parameters `bounding_boxes` and `shape` to
+ BoundingBoxesOnImage.copy()`.
+* Added parameters `bounding_boxes` and `shape` to
+ BoundingBoxesOnImage.deepcopy()`.
+* Switched `KeypointsOnImage.copy()` to a custom copy operation (away
+ from module `copy` module).
+* Switched `PolygonsOnImage.copy()` to a custom copy operation (away
+ from module `copy` module).
+* Added parameters `polygons` and `shape` to
+ PolygonsOnImage.copy()`.
+* Added parameters `polygons` and `shape` to
+ PolygonsOnImage.deepcopy()`.
+* Switched augmenters to use in-place functions for keypoints,
+ bounding boxes, line strings and polygons.
+
+
+## Added Standardized LUT Methods [#542](https://github.com/aleju/imgaug/pull/542)
+
+This patch standardized the handling of lookup tables throughout the library.
+
+* Added `imgaug.imgaug.apply_lut()`, which applies a lookup table to an image.
+* Added `imgaug.imgaug.apply_lut_()`. In-place version of `apply_lut()`.
+* Refactored all augmenters to use these new LUT functions.
+ This likely fixed some so-far undiscovered bugs in augmenters using LUT
+ tables.
+
+
+## Added Drawing of Bounding Box Labels [#545](https://github.com/aleju/imgaug/pull/545)
+
+When drawing bounding boxes on images via `BoundingBox.draw_on_image()`
+or `BoundingBoxesOnImage.draw_on_image()`, a box containing the label will now
+be drawn over each bounding box's rectangle. If the bounding box's label is
+set to `None`, the label box will not be drawn. For more detailed control,
+use `BoundingBox.draw_label_on_image()`.
+
+* Added method `imgaug.augmentables.BoundingBox.draw_label_on_image()`.
+* Added method `imgaug.augmentables.BoundingBox.draw_box_on_image()`.
+* Changed method `imgaug.augmentables.BoundingBox.draw_on_image()`
+ to automatically draw a bounding box's label.
+
+
+## Added Index-based Access to Coordinate-based `*OnImage` Instances [#547](https://github.com/aleju/imgaug/pull/547)
+
+Enabled index-based access to coordinate-based `*OnImage` instances, i.e. to
+`KeypointsOnImage`, `BoundingBoxesOnImage`, `LineStringsOnImage` and
+`PolygonsOnImage`. This allows to do things like
+`bbsoi = BoundingBoxesOnImage(...); bbs = bbsoi[0:2];`.
+
+* Added `imgaug.augmentables.kps.KeypointsOnImage.__getitem__()`.
+* Added `imgaug.augmentables.bbs.BoundingBoxesOnImage.__getitem__()`.
+* Added `imgaug.augmentables.lines.LineStringsOnImage.__getitem__()`.
+* Added `imgaug.augmentables.polys.PolygonsOnImage.__getitem__()`.
+
+
+## Added `Rain` and `RainLayer` Augmenters [#551](https://github.com/aleju/imgaug/pull/551)
+
+Added augmenter(s) to create fake rain effects. They currently seem to work
+best at around medium-sized images (~224px).
+
+* Added `imgaug.augmenters.weather.Rain`.
+* Added `imgaug.augmenters.weather.RainLayer`.
+
+
+## Added `round` Parameter to `Discretize` [#553](https://github.com/aleju/imgaug/pull/553)
+
+Added the parameter `round` to `imgaug.parameters.Discretize`. The parameter
+defaults to `True`, i.e. the default behaviour of `Discretize` did not change.
+
+
+## Added `RandAugment` Augmenter [#553](https://github.com/aleju/imgaug/pull/553)
+
+Added a RandAugment augmenter, similar to the one described in the paper
+"RandAugment: Practical automated data augmentation with a reduced
+search space".
+
+Note: This implementation makes a best guess about some hyperparameters
+that were neither in the paper nor in the code repsitory clearly
+defined.
+
+Note: This augmenter differs from the paper implementation by applying
+a fix to their color augmentations. The ones in the paper's implementation
+seemed to increase in strength as the magnitude was decreased below
+a threshold.
+
+Note: This augmenter currently only accepts image inputs. Other input
+types (e.g. bounding boxes) will be rejected.
+
+* Added module `imgaug.augmenters.collections`
+* Added augmenter `imgaug.augmenters.collections.RandAugment`.
+
+
+## Added and Improved Warnings for Probably-Wrong Image Inputs [#594](https://github.com/aleju/imgaug/pull/594)
+
+Improved the errors and warnings on image augmentation calls.
+`augment_image()` will now produce a more self-explanatory error
+message when calling it as in `augment_image(list of images)`.
+Calls of single-image augmentation functions (e.g.
+`augment(image=...)`) with inputs that look like multiple images
+will now produce warnings. This is the case for `(H, W, C)`
+inputs when `C>=32` (as that indicates that `(N, H, W)` was
+actually provided).
+Calls of multi-image augmentation functions (e.g.
+`augment(images=...)`) with inputs that look like single images
+will now produce warnings. This is the case for `(N, H, W)`
+inputs when `W=1` or `W=3` (as that indicates that `(H, W, C)`
+was actually provided.)
+
+* Added an assert in `augment_image()` to verify that inputs are
+ arrays.
+* Added warnings for probably-wrong image inputs in
+ `augment_image()`, `augment_images()`, `augment()` (and its
+ alias `__call__()`).
+* Added module `imgaug.augmenters.base`.
+* Added warning
+ `imgaug.augmenters.base.SuspiciousMultiImageShapeWarning`.
+* Added warning
+ `imgaug.augmenters.base.SuspiciousSingleImageShapeWarning`.
+* Added `imgaug.testutils.assertWarns`, similar to `unittest`'s
+ `assertWarns`, but available in python <3.2.
+
+
+
+
+# Changed
+
+## Improved RNG Handling during Polygon Augmentation [#447](https://github.com/aleju/imgaug/pull/447)
+
+Changed `Augmenter.augment_polygons()` to copy the augmenter's RNG
+before starting concave polygon recovery. This is done for cleanliness and
+should not have any effects for users.
+Also removed RNG copies in `_ConcavePolygonRecoverer` to improve performance.
+
+
+## Pooling Augmenters now Affect Maps [#457](https://github.com/aleju/imgaug/pull/457)
+
+Pooling augmenters were previously implemented so that they did not pool
+the arrays of maps (i.e. heatmap arrays, segmentation map arrays). Only
+the image shape saved within `HeatmapsOnImage.shape` and
+`SegmentationMapsOnImage.shape` were updated. That was done because the library
+can handle map arrays that are larger than the corresponding images and hence
+no pooling was necessary for the augmentation to work correctly. This was now
+changed and pooling augmenters will also pool map arrays
+(if `keep_size=False`). The motiviation for this change is that the old
+behaviour was unintuitive and inconsistent with other augmenters (e.g. `Crop`).
+
+
+## Affine Translation Precision [#489](https://github.com/aleju/imgaug/pull/489)
+
+Removed a rounding operation in `Affine` translation that would unnecessarily
+round floats to integers. This should make coordinate augmentation overall
+more accurate.
+
+
+## `Affine.get_parameters()` and `translate_px`/`translate_percent` [#508](https://github.com/aleju/imgaug/pull/508)
+
+Changed `Affine.get_parameters()` to always return a tuple `(x, y, mode)`
+for translation, where `mode` is either `px` or `percent`,
+and `x` and `y` are stochastic parameters. `y` may be `None` if the same
+parameter (and hence samples) are used for both axes.
+
+
+## Removed Outdated "Don't Import from this Module" Messages [#539](https://github.com/aleju/imgaug/pull/539)
+
+The docstring of each module in ``imgaug.augmenters`` previously included a
+suggestion to not directly import from that module, but instead use
+``imgaug.augmenters.``. That was due to the categorization
+still being unstable. As the categorization has now been fairly stable
+for a long time, the suggestion was removed from all modules. Calling
+``imgaug.augmenters.`` instead of
+``imgaug.augmenters..`` is however still the
+preferred way.
+
+
+## Standardized `shift()` Interfaces of Coordinate-Based Augmentables [#548](https://github.com/aleju/imgaug/pull/548)
+
+The interfaces for shift operations of all coordinate-based
+augmentables (Keypoints, BoundingBoxes, LineStrings, Polygons)
+were standardized. All of these augmentables have now the same
+interface for shift operations. Previously, Keypoints used
+a different interface (using `x` and `y` arguments) than the
+other augmentables (using `top`, `right`, `bottom`, `left`
+arguments). All augmentables use now the interface of Keypoints
+as that is simpler and less ambiguous. Old arguments are still
+accepted, but will produce deprecation warnings. Change the
+arguments to `x` and `y` following `x=left-right` and
+`y=top-bottom`.
+
+**[breaking]** This breaks if one relied on calling `shift()` functions of
+`BoundingBox`, `LineString`, `Polygon`, `BoundingBoxesOnImage`,
+`LineStringsOnImage` or `PolygonsOnImage` without named arguments.
+E.g. `bb = BoundingBox(...); bb_shifted = bb.shift(1, 2, 3, 4);`
+will produce unexpected outputs now (equivalent to
+`shift(x=1, y=2, top=3, right=4, bottom=0, left=0)`),
+while `bb_shifted = bb.shift(top=1, right=2, bottom=3, left=4)` will still
+work as expected.
+
+* Added arguments `x`, `y` to `BoundingBox.shift()`, `LineString.shift()`
+ and `Polygon.shift()`.
+* Added arguments `x`, `y` to `BoundingBoxesOnImage.shift()`,
+ `LineStringsOnImage.shift()` and `PolygonsOnImage.shift()`.
+* Marked arguments `top`, `right`, `bottom`, `left` in
+ `BoundingBox.shift()`, `LineString.shift()` and `Polygon.shift()`
+ as deprecated. This also affects the corresponding `*OnImage`
+ classes.
+* Added function `testutils.wrap_shift_deprecation()`.
+
+
+## Simplified Standard Parameters of Augmenters [#567](https://github.com/aleju/imgaug/pull/567) [#595](https://github.com/aleju/imgaug/pull/595)
+
+The patch changed the standard parameters shared by all augmenters to a
+reduced and more self-explanatory set. Previously, all augmenters
+shared the parameters `name`, `random_state` and `deterministic`.
+The new parameters are `seed` and `name`.
+
+`deterministic` was removed as it was hardly ever used and because
+it caused frequently confusion with regards to its meaning. The
+parameter is still accepted but will now produce a deprecation
+warning. Use `.to_deterministic()` instead.
+
+Reminder: `to_deterministic()` is necessary if you want to get
+the same samples in *consecutive* augmentation calls. It is *not*
+necessary if you want your generated samples to be dependent on
+an initial seed or random state as that is *always* the case
+anyways. To use non-random initial seeds, use either
+the `seed` parameter (augmenter-specific seeding) or
+`imgaug.random.seed()` (global seeding, affects only augmenters
+for which the `seed` parameter was not explicitly provided).
+
+`random_state` was renamed to `seed` as providing a seed value
+is the more common use case compared to providing a random state.
+Many users also seemed to be unaware that `random_state` accepted
+seed values. The new name should make this more clear.
+The old parameter `random_state` is still accepted, but will
+likely be deprecated in the future.
+
+**[breaking]** This patch breaks if one relied on the order of
+`name`, `random_state` and `deterministic`. The new order is now
+`seed=..., name=..., random_state=..., deterministic=...` (with the
+latter two parameters being outdated or deprecated)
+as opposed to previously
+`name=..., deterministic=..., random_state=...`.
+
+
+## Improved Default Values of Augmenters [#582](https://github.com/aleju/imgaug/pull/582)
+
+**[breaking]** Most augmenters had previously default values that
+made them equivalent to identity functions. Users had to explicitly
+change the defaults to proper values in order to "activate"
+augmentations. To simplify the usage of the library, the default
+values of most augmenters were changed to medium-strength
+augmentations. E.g.
+`Sequential([Affine(), UniformVoronoi(), CoarseDropout()])`
+should now produce decent augmentations.
+
+A few augmenters were set to always-on, maximum-strength
+augmentations. This is the case for:
+
+* `Grayscale` (always fully grayscales images, use
+ `Grayscale((0.0, 1.0))` for random strengths)
+* `RemoveSaturation` (same as `Grayscale`)
+* `Fliplr` (always flips images, use `Fliplr(0.5)` for 50%
+ probability)
+* `Flipud` (same as `Fliplr`)
+* `TotalDropout` (always drops everything, use
+ `TotalDropout(0.1)` to drop everything for 10% of all images)
+* `Invert` (always inverts images, use `Invert(0.1)` to invert
+ 10% of all images)
+* `Rot90` (always rotates exactly once clockwise by 90 degrees,
+ use `Rot90((0, 3))` for any rotation)
+
+These settings seemed to better match user-expectations.
+Such maximum-strength settings however were not chosen for all
+augmenters where one might expect them. The defaults are set to
+varying strengths for, e.g. `Superpixels` (replaces only some
+superpixels with cellwise average colors), `UniformVoronoi` (also
+only replaces some cells), `Sharpen` (alpha-blends with variable
+strength, the same is the case for `Emboss`, `EdgeDetect` and
+`DirectedEdgeDetect`) and `CLAHE` (variable clip limits).
+
+*Note*: Some of the new default values will cause issues with
+non-`uint8` inputs.
+
+*Note*: The defaults for `per_channel` and `keep_size` were not
+adjusted. It is currently still the default behaviour of all
+augmenters to affect all channels in the same way and to resize
+their outputs back to the input sizes.
+
+The exact changes to default values are listed below.
+
+**imgaug.arithmetic**
+
+ * `Add`
+ * `value`: `0` -> `(-20, 20)`
+ * `AddElementwise`
+ * `value`: `0` -> `(-20, 20)`
+ * `AdditiveGaussianNoise`
+ * `scale`: `0` -> `(0, 15)`
+ * `AdditiveLaplaceNoise`
+ * `scale`: `0` -> `(0, 15)`
+ * `AdditivePoissonNoise`
+ * `scale`: `0` -> `(0, 15)`
+ * `Multiply`
+ * `mul`: `1.0` -> `(0.8, 1.2)`
+ * `MultiplyElementwise`:
+ * `mul`: `1.0` -> `(0.8, 1.2)`
+ * `Dropout`:
+ * `p`: `0.0` -> `(0.0, 0.05)`
+ * `CoarseDropout`:
+ * `p`: `0.0` -> `(0.02, 0.1)`
+ * `size_px`: `None` -> `(3, 8)`
+ * `min_size`: `4` -> `3`
+ * Default for `size_px` is only used if neither `size_percent`
+ nor `size_px` is provided by the user.
+ * `CoarseSaltAndPepper`:
+ * `p`: `0.0` -> `(0.02, 0.1)`
+ * `size_px`: `None` -> `(3, 8)`
+ * `min_size`: `4` -> `3`
+ * Default for `size_px` is only used if neither `size_percent`
+ nor `size_px` is provided by the user.
+ * `CoarseSalt`:
+ * `p`: `0.0` -> `(0.02, 0.1)`
+ * `size_px`: `None` -> `(3, 8)`
+ * `min_size`: `4` -> `3`
+ * Default for `size_px` is only used if neither `size_percent`
+ nor `size_px` is provided by the user.
+ * `CoarsePepper`:
+ * `p`: `0.0` -> `(0.02, 0.1)`
+ * `size_px`: `None` -> `(3, 8)`
+ * `min_size`: `4` -> `3`
+ * Default for `size_px` is only used if neither `size_percent`
+ nor `size_px` is provided by the user.
+ * `SaltAndPepper`:
+ * `p`: `0.0` -> `(0.0, 0.03)`
+ * `Salt`:
+ * `p`: `0.0` -> `(0.0, 0.03)`
+ * `Pepper`:
+ * `p`: `0.0` -> `(0.0, 0.05)`
+ * `ImpulseNoise`:
+ * `p`: `0.0` -> `(0.0, 0.03)`
+ * `Invert`:
+ * `p`: `0` -> `1`
+ * `JpegCompression`:
+ * `compression`: `50` -> `(0, 100)`
+
+**imgaug.blend**
+
+ * `BlendAlpha`
+ * `factor`: `0` -> `(0.0, 1.0)`
+ * `BlendAlphaElementwise`
+ * `factor`: `0` -> `(0.0, 1.0)`
+
+**imgaug.blur**
+
+ * `GaussianBlur`:
+ * `sigma`: `0` -> `(0.0, 3.0)`
+ * `AverageBlur`:
+ * `k`: `1` -> `(1, 7)`
+ * `MedianBlur`:
+ * `k`: `1` -> `(1, 7)`
+ * `BilateralBlur`:
+ * `d`: `1` -> `(1, 9)`
+ * `MotionBlur`:
+ * `k`: `5` -> `(3, 7)`
+
+**imgaug.color**
+
+ * `MultiplyHueAndSaturation`:
+ * `mul_hue`: `None` -> `(0.5, 1.5)`
+ * `mul_saturation`: `None` -> `(0.0, 1.7)`
+ * These defaults are only used if the user provided neither
+ `mul` nor `mul_hue` nor `mul_saturation`.
+ * `MultiplyHue`:
+ * `mul`: `(-1.0, 1.0)` -> `(-3.0, 3.0)`
+ * `AddToHueAndSaturation`:
+ * `value_hue`: `None` -> `(-40, 40)`
+ * `value_saturation`: `None` -> `(-40, 40)`
+ * These defaults are only used if the user provided neither
+ `value` nor `value_hue` nor `value_saturation`.
+ * `Grayscale`:
+ * `alpha`: `0` -> `1`
+
+**imgaug.contrast**
+
+ * `GammaContrast`:
+ * `gamma`: `1` -> `(0.7, 1.7)`
+ * `SigmoidContrast`:
+ * `gain`: `10` -> `(5, 6)`
+ * `cutoff`: `0.5` -> `(0.3, 0.6)`
+ * `LogContrast`:
+ * `gain`: `1` -> `(0.4, 1.6)`
+ * `LinearContrast`:
+ * `alpha`: `1` -> `(0.6, 1.4)`
+ * `AllChannelsCLAHE`:
+ * `clip_limit`: `40` -> `(0.1, 8)`
+ * `tile_grid_size_px`: `8` -> `(3, 12)`
+ * `CLAHE`:
+ * `clip_limit`: `40` -> `(0.1, 8)`
+ * `tile_grid_size_px`: `8` -> `(3, 12)`
+
+**convolutional**
+
+ * `Sharpen`:
+ * `alpha`: `0` -> `(0.0, 0.2)`
+ * `lightness`: `1` -> `(0.8, 1.2)`
+ * `Emboss`:
+ * `alpha`: `0` -> `(0.0, 1.0)`
+ * `strength`: `1` -> `(0.25, 1.0)`
+ * `EdgeDetect`:
+ * `alpha`: `0` -> `(0.0, 0.75)`
+ * `DirectedEdgeDetect`:
+ * `alpha`: `0` -> `(0.0, 0.75)`
+
+**imgaug.flip**
+
+ * `Fliplr`:
+ * `p`: `0` -> `1`
+ * `Flipud`:
+ * `p`: `0` -> `1`
+
+**imgaug.geometric**
+
+ * `Affine`:
+ * `scale`: `1` -> `{"x": (0.9, 1.1), "y": (0.9, 1.1)}`
+ * `translate_percent`: None -> `{"x": (-0.1, 0.1), "y": (-0.1, 0.1)}`
+ * `rotate`: `0` -> `(-15, 15)`
+ * `shear`: `0` -> `shear={"x": (-10, 10), "y": (-10, 10)}`
+ * These defaults are only used if no affine transformation
+ parameter was set by the user. Otherwise the not-set
+ parameters default again towards the identity function.
+ * `PiecewiseAffine`:
+ * `scale`: `0` -> `(0.0, 0.04)`
+ * `nb_rows`: `4` -> `(2, 4)`
+ * `nb_cols`: `4` -> `(2, 4)`
+ * `PerspectiveTransform`:
+ * `scale`: `0` -> `(0.0, 0.06)`
+ * `ElasticTransformation`:
+ * `alpha`: `0` -> `(0.0, 40.0)`
+ * `sigma`: `0` -> `(4.0, 8.0)`
+ * `Rot90`:
+ * `k`: `(no default)` -> `k=1`
+
+**imgaug.pooling**
+
+ * `AveragePooling`:
+ * `k`: `(no default)` -> `(1, 5)`
+ * `MaxPooling`:
+ * `k`: `(no default)` -> `(1, 5)`
+ * `MinPooling`:
+ * `k`: `(no default)` -> `(1, 5)`
+ * `MedianPooling`:
+ * `k`: `(no default)` -> `(1, 5)`
+
+**imgaug.segmentation**
+
+ * `Superpixels`:
+ * `p_replace`: `0.0` -> `(0.5, 1.0)`
+ * `n_segments`: `100` -> `(50, 120)`
+ * `UniformVoronoi`:
+ * `n_points`: `(no default)` -> `(50, 500)`
+ * `p_replace`: `1.0` -> `(0.5, 1.0)`.
+ * `RegularGridVoronoi`:
+ * `n_rows`: `(no default)` -> `(10, 30)`
+ * `n_cols`: `(no default)` -> `(10, 30)`
+ * `p_drop_points`: `0.4` -> `(0.0, 0.5)`
+ * `p_replace`: `1.0` -> `(0.5, 1.0)`
+ * `RelativeRegularGridVoronoi`: Changed defaults from
+ * `n_rows_frac`: `(no default)` -> `(0.05, 0.15)`
+ * `n_cols_frac`: `(no default)` -> `(0.05, 0.15)`
+ * `p_drop_points`: `0.4` -> `(0.0, 0.5)`
+ * `p_replace`: `1.0` -> `(0.5, 1.0)`
+
+**imgaug.size**
+
+ * `CropAndPad`:
+ * `percent`: `None` -> `(-0.1, 0.1)`
+ * This default is only used if the user has provided
+ neither `px` nor `percent`.
+ * `Pad`:
+ * `percent`: `None` -> `(0.0, 0.1)`
+ * This default is only used if the user has provided
+ neither `px` nor `percent`.
+ * `Crop`:
+ * `percent`: `None` -> `(0.0, 0.1)`
+ * This default is only used if the user has provided
+ neither `px` nor `percent`.
+
+
+## `setup.py` Now Accepts any `opencv-*` Installation [#586](https://github.com/aleju/imgaug/pull/586)
+
+`setup.py` was changed so that it now accepts `opencv-python`,
+`opencv-python-headless`, `opencv-contrib-python` and
+`opencv-contrib-python-headless` as valid OpenCV installations.
+Previously, only `opencv-python-headless` was accepted, which
+could easily cause conflicts when another one of the mentioned
+libraries was already installed.
+If none of the mentioned libraries is installed, `setup.py`
+will default to adding `opencv-python` as a requirement.
+
+Note that this may still cause issues if a single installation
+call installs multiple libraries and the order is random.
+`imgaug` will then currently request `opencv-python-headless`
+to be installed, which may differ from what a later installed
+library requests. Try to ensure that the other library is installed
+first in these cases.
+
+
+## Unified OpenCV Input Normalization [#565](https://github.com/aleju/imgaug/pull/565)
+
+Changed various augmenters to use the same normalization for OpenCV
+inputs. This probably fixes some previously undiscovered bugs.
+
+
+## Renamed In-place Methods [#444](https://github.com/aleju/imgaug/pull/444)
+
+* Renamed `Augmenter.reseed()` to `Augmenter.seed_()`. The old name is
+ now deprecated.
+* Renamed `Augmenter.remove_augmenters_inplace()` to
+ `Augmenter.remove_augmenters_()`. The old name is now deprecated.
+
+
+## Deprecated `AffineCv2` [#540](https://github.com/aleju/imgaug/pull/540)
+
+Deprecated `imgaug.augmenters.geometric.AffineCv2`.
+Use `imgaug.augmenters.geometric.Affine` instead. [#540](https://github.com/aleju/imgaug/pull/540)
+
+
+
+
+# Refactored
+
+## Refactored According to pylint Requirements [#504](https://github.com/aleju/imgaug/pull/504)
+
+* Refactored all core library files to fulfill (most) pylint requirements.
+* [rarely breaking] Renamed
+ `imgaug.augmenters.size.KeepSizeByResize.get_shapes()` to `_get_shapes()`.
+* Added a project-specific pylint configuration.
+
+
+
+
+# Fixed
+
+* Fixed `Resize` always returning an `uint8` array during image augmentation
+ if the input was a single numpy array and all augmented images had the
+ same shape. [#442](https://github.com/aleju/imgaug/pull/442) [#443](https://github.com/aleju/imgaug/pull/443)
+* Fixed `Affine` coordinate-based augmentation applying wrong offset
+ when shifting images to/from top-left corner. This would lead to an error
+ of around 0.5 to 1.0 pixels. [#446](https://github.com/aleju/imgaug/pull/446)
+* Fixed keypoint augmentation in `PiecewiseAffine` potentially being
+ unaligned if a `KeypointsOnImage` instance contained no keypoints. [#446](https://github.com/aleju/imgaug/pull/446)
+* Fixed `imgaug.validation.convert_iterable_to_string_of_types()` crashing due
+ to not converting types to strings before joining them. [#446](https://github.com/aleju/imgaug/pull/446)
+* Fixed `imgaug.validation.assert_is_iterable_of()` producing a not
+ well-designed error if the input was not an iterable. [#446](https://github.com/aleju/imgaug/pull/446)
+* Fixed image normalization crashing when an input ndarray of multiple images
+ was changed during augmentation to a list of multiple images with different
+ shapes *and* the original input ndarray represented a single image or
+ a collection of 2D `(H,W)` images. This problem affected `augment()`,
+ `augment_batch()` and `augment_batches()`.
+* Fixed a typo in an image normalization error message. [#451](https://github.com/aleju/imgaug/pull/451)
+* Fixed a problem in `WithChannels` that could lead random sampling in child
+ augmenters being unaligned between images and corresponding non-image
+ data. [#451](https://github.com/aleju/imgaug/pull/451)
+* Added aliases to `imgaug.random.RNG` for some outdated numpy random number
+ sampling methods that existed in `numpy.random.RandomState` but not in
+ numpy's new RNG system (1.17+). These old methods are not used in `imgaug`,
+ but some custom augmenters and `Lambda` calls may require them when
+ interacting with the provided `random_state` instances. [#486](https://github.com/aleju/imgaug/pull/486)
+* Fixed `Affine` producing unaligned augmentations between images and
+ segmentation maps or heatmaps when using `translate_px` and the segmentation
+ map or heatmap had a different height/width than corresponding image. [#489](https://github.com/aleju/imgaug/pull/489)
+* Fixed a crash in `SnowflakesLayer` that could occur when using values
+ close to `1.0` for `flake_size`. [#471](https://github.com/aleju/imgaug/pull/471)
+* Fixed `MultiplyHueAndSaturation` crashing if the RNG provided via
+ `random_state` was not `None` or `imgaug.random.RNG`. [#493](https://github.com/aleju/imgaug/pull/493)
+* Fixed `CloudLayer.draw_on_image()` producing tuples instead of arrays
+ as output for `float` input images. [#540](https://github.com/aleju/imgaug/pull/540)
+* Fixed `Affine` parameter `translate_px` behaving like `translate_percent`
+ if a continuous stochastic parameter was provided.
+ Analogously `translate_percent` would behave like `translate_px` if
+ a discrete stochastic parameter was provided. [#508](https://github.com/aleju/imgaug/pull/508)
+* Fixed code hanging indefinitely when using multicore augmentation
+ on NixOS. [#414](https://github.com/aleju/imgaug/issues/414) [#510](https://github.com/aleju/imgaug/pull/510)
+* Fixed a deprecation warning and potential crash in python 3.8
+ related to the use of `collections` instead of `collections.abc`. [#527](https://github.com/aleju/imgaug/pull/527)
+* Fixed deprecated `scipy.fromfunction()` being called. [#529](https://github.com/aleju/imgaug/pull/529)
+* Fixed `imgaug.random.normalize_generator()` crashing in numpy 1.18.
+ The function relied on `numpy.random.bit_generator.BitGenerator`, which
+ was moved in numpy 1.18 to `numpy.random.BitGenerator` without a
+ deprecation period for the old name. [#534](https://github.com/aleju/imgaug/pull/534)
+* Fixed an issue that could lead to endlessly hanging programs on some OS
+ when using multicore augmentation (e.g. via pool) and augmenters using
+ OpenCV. [#535](https://github.com/aleju/imgaug/pull/535)
+* Fixed `imgaug.random.seed()` not seeding the global `RNG` in-place
+ in numpy 1.17+. The (unfixed) function instead created a new
+ global `RNG` with the given seed. This set the seed of augmenters
+ created *after* the `seed()` call, but not of augmenters created
+ *before* the `seed()` call as they would continue to use the old
+ global RNG. [#557](https://github.com/aleju/imgaug/pull/557)
+* Fixed `cval` in `ElasticTransformation` resulting in new pixels in RGB images
+ being filled with `(cval, 0, 0)` instead of `(cval, cval, cval)`. [#561](https://github.com/aleju/imgaug/pull/561) [#562](https://github.com/aleju/imgaug/pull/562)
+* Fixed some augmenters in module `weather` not transferring seed values
+ or random states that were provided upon creation to child augmenters. [#568](https://github.com/aleju/imgaug/pull/568)
+* Fixed an inaccuracy in `PerspectiveTransform` that could lead to slightly
+ misaligned transformations between images and coordinate-based
+ augmentables (e.g. bounding boxes). The problem was more significant the
+ smaller the images and larger the `scale` values were. It was also
+ worsened by using `fit_output`. [#585](https://github.com/aleju/imgaug/pull/585)
+* Fixed `KeepSizeByResize` potentially crashing if a single numpy array
+ was provided as the input for an iterable of images (as opposed to
+ a list of numpy arrays). [#590](https://github.com/aleju/imgaug/pull/590)