Differences

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--- isp:white_balance [2018/06/04 09:10] – created Igor Yefmov
+++ isp:white_balance [2019/05/09 00:53] – [Color correction for white temperature] Igor Yefmov
@@ Line 12: / Line 12: @@
 For the calibration purposes we have acquired a Philips "Hue White and Color Ambiance A19 LED Starter Kit" that allowed us to test various illumination scenarios for a range of color temperatures. For a given white color temperature setting we have dialed the red and blue gains to make the scene "white" (leaving the green gain at its constant value of ''1024'').
-Corrections to the red channel were way more noticeable than those to the blue one so we approximated the blue gains' graph with a single line, described by the formula ''B = 4205.4 - T*0.4087''.
+Corrections to the red channel were way more noticeable than those to the blue one so we approximated the blue gains' graph with a single line, described by the formula \(B = 4205.4 - T*0.4087\).
-Red channel gains are approximated by two line segments, bordering the ''3500''°K mark:
+Red channel gains are approximated by two line segments, bordering the \(3500°K\) mark:
-below ''3500''°K: ''R = 467.6 + T * 0.166'' \\
-above ''3500''°K: ''R = 82 + T * 0.277''
+\[
+R =
+ \begin{cases}
+.6 + T * 0.166 & \quad \text{if } T < 3500°K \\
++ T * 0.277 & \quad \text{if } T >= 3500°K
+ \end{cases}
+\]
 {{:isp:wb_pig-2.jpg?600|}}
 ==== Experimental data and verification ====

SUB2r