Currently the computer R, G, B three dimensions to represent the color, each color can be described by 8-bit gray scale of 256, it can be described as a total of 256 256 256 = 16,777,216 colors.
But for the gray value of each dimension, if you increase the brightness in accordance with changes linearly values have a big problem: in fact, the human eye is more sensitive to changes in brightness in the dark, that the human perception of light intensity RGB values and the actual non-linear.
Thus, when the picture in the memory, the pixel color of the final output to make a conversion is achieved by setting different gamma values, as shown below:
Output = POW (INPUT, gamma)
is recommended set to 2.2.
Formulas and recommended PBRT book gamma values differ, but personally do a little experiment, and gamma 2.2 to the naked eye to see the results did not differ much:
The figure is not to do gamma correction and gamma correction comparison chart can be see some brighter obviously right:
Principle and Gamma correction
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Origin www.cnblogs.com/wickedpriest/p/12389127.html
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