Question

What does the look-up table filter do?

Answer

The lookup table filter allows you to define the mapping of input to output pixel values.

The lookup table uses a segmented line with three adjustment points you can drag to adjust the input to output pixel mapping. It adjusts red, green, and blue colors equally.

The bottom axis represents input values while the left axis represents output values. A value of 0 is 100% black while a value of 255 is 100% white.

• The Reset Button adjusts the lookup table to have a one-to-one mapping between input and output values.
• The Brightness Buttons increase or decrease brightness by moving the lookup table adjustment points.
• The Contrast Buttons increase or decrease contrast by moving the lookup table adjustment points.
• The Gamma Buttons increase or decrease gamma by moving the lookup table adjustment points.

The lookup table is a powerful filter that can efficiently simulate complex operations.