The Gamma correction is used to compensate for the non-linear response of the screen. The grey-level values of the image are corrected to take the screen response into account.
From the Graphic Interface
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The Gamma correction value is set by comparing the 3 grey surfaces: two of these (left and right) are composed of a mix of black and white lines, the other (center) is a mid-level grey. The visual stimuli of all 3 surfaces should be the same.
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This slider is used to select the Gamma correction value. Adjust the slider so that the 3 grey surfaces have the same intensity. |
From the Display Area
There is no Display Area interaction specific to this tool.
From the Keyboard
There is no keyboard interface specific to this tool.
From the Command Line
System Variables defined in this tool:
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$GAMMA_CUR |
(F32) |
Current Gamma value (Default = 1.0) |
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$GAMMA_NB |
(U16,R) |
Number on entries in the Gamma table (= 256) |
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$GAMMA_ALPHA |
(A,F32) |
Array of $GAMMA_NB Gamma map values used to remap the "Alpha" color values (glPixelMapfv( GL_PIXEL_MAP_A_TO_A, nb, alpha)) |
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$GAMMA_PT |
(A,F32) |
Array of $GAMMA_NB Gamma map values used to remap the R G and B color values (glPixelMapfv( GL_PIXEL_MAP_R_TO_R, nb, pt)) |
Text commands defined in this tool:
Gamma: Set value
Assign the value to the $GAMMA_CUR variable that set the current Gamma correction value (0.3 <= Gamma <= 3.0)