List of terms and definitions
| Term | Definition |
|---|---|
| Max(R,G,B) | The maximum value of an RGB triplet. Max(0.1. 0.2, 0.3) = 0.3 |
| Min(R, G, B) | THe minimum value of an RGB triplet. ALso equivelant ot the purity of that triplet |
| Purity | How close an RGB triplet is to the hull of it's colour space. [0.0, 0.4, 0.6] is maximally pure as the red component is on the hull. A minimally pure colour is an achromatic triplet (R=G=B) as all the components are equally far from the hull |
| Normalize | Spread the image data to fill the range 0.0 - 1.0. To do this subtract the lowest none zero pixel value from all pixels and then multiply all pixels by 1 divided by the max pixel value |
| Offset | The base value compnent of an RGB triplet. E.G. [0.1, 0.2, 0.3] has an offset of [0.1, 0.1, 0.1]. An RGB triplet can be "offset" up or down by a set amount. E.G. we can offset [0.1, 0.2, 0.3] by +0.1 to get [0.2, 0.3, 0.4] |
| Gain | The reamining colour component of and RGB triplet after the offset has been removed. E.G. The gain component of [0.1, 0.2, 0.3] is [0.0, 0.1, 0.2]. A triplet can be gained by multiplying either component wise or all three components together (uniform) |
| Pictorial exposure | Changing the exposure of the image post formation. Increasing the pictorial exposure leads to a fogging of the image, a totally black stimuli would have an offset |
| Stimuli Exposure | Adjusting the energy in front of the camera either by add/removing light or changing the exposure time/aperture. A fully absorbative surface would remain at zero energy. This has to happen pre image formation otherwise the contrast of the image will fundamentally change and break the image |