ContrastLum
Function
This applies a contrast change on the image, with a smooth falloff on
both the low and high ends. You can also move the center of the contrast
curve up and down (ie, moving it down makes your overall image brighter).
Note that this contrast is based on the luminance of the pixel, so it
balances red, green, and blue. This means an image with strong primary
colors will look differently from the same values with ContrastRGB,
which evaluates each channel separately.
Also note that we have a rolloff built into the contrast function, giving
you a smooth falloff at the ends of the curve. This is controlled by the
softClip parameter.
Parameters
|
Type
|
Defaults
|
Function
|
value |
float
|
1 |
The contrast value. A higher value means
it pushes your RGB values towards 0 and 1. A value of 0 means no change.
A lower value means low contrast. |
center |
float
|
.5 |
This is the center of the contrast curve.
A lower value means a brighter image. |
softClip |
float
|
0 |
This controls the drop-off of the curve.
When it is increased to 1, you have maximum smoothness of the curve. |
Synopsis
image ContrastLum(
image In,
float value,
float center,
float softClip
);
Script
image = ContrastLum(
image,
value,
center,
softClip
);
Command Line
shake -contrastlum value center softClip
Examples
shake lisa.iff -contrastl 2
shake lisa.iff -contrastl 2 .3
shake lisa.iff -contrastl 2 .8
shake lisa.iff -contrastl .8
See Also
ContrastRGB, Gamma,
Add, Mult,
|