Workflow Guide preprocessing

Optionally, you can start off your workflow by enhancing your images, which can be vital for the following binarization. In this processing step, the raw image is taken and enhanced by e.g. grayscale conversion, brightness normalization, noise filtering, etc.

Note: ocrd-preprocess-image can be used to run arbitrary shell commands for preprocessing (original or derived) images, and can be seen as a generic OCR-D wrapper for many of the following workflow steps, provided a matching external tool exists. (The only restriction is that the tool must not change image size or the position/coordinates of its content.)

Available processors

Processor	Parameter	Remark	Call
ocrd-im6convert	-P output-format image/tiff	for output-options see IM Documentation	ocrd-im6convert -I OCR-D-IMG -O OCR-D-ENH -P output-format image/tiff
ocrd-preprocess-image	-P input_feature_filter binarized -P output_feature_added binarized -P command "scribo-cli sauvola-ms-split '@INFILE' '@OUTFILE' --enable-negate-output"	for parameters and command examples (presets) see the Readme	ocrd-preprocess-image -I OCR-D-IMG -O OCR-D-PREP -P output_feature_added binarized -P command "scribo-cli sauvola-ms-split @INFILE @OUTFILE --enable-negate-output"
ocrd-skimage-normalize			ocrd-skimage-normalize -I OCR-D-IMG -O OCR-D-NORM
ocrd-skimage-denoise-raw			ocrd-skimage-denoise-raw -I OCR-D-IMG -O OCR-D-DENOISE

Notes on parameter usage

E.g.

• which parameters do you use with what values?
• which parameters are insufficiently documented?
• which aspects of a processor should be parameterizable but are not?

Notes on document-specific usage

E.g. which processors worked best with what material? -- feel free to post sample images here, too.