Illustrates using the very low-level LUT routines to accomplish a "sigmoid" adjustment.
A Sigmoid function is an "S" -shaped curve with a number of specific properties. However, for the purposes here it is sufficient to think of it as a double-sided "gamma" adjustment. It can be used to simultaneously decrease the "gamma" of darker pixels, while increasing the "gamma" of lighter pixels.

Source code: LUT_03_Sigmoid

Built with Processing