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| isp:white_balance [2019/05/09 00:53] – [Color correction for white temperature] Igor Yefmov | isp:white_balance [2019/05/09 00:54] – [Color correction for white temperature] Igor Yefmov | ||
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| For our purposes, we are using individual color channel **gains** to compensate for a given temperature. Lower temperature "white light" needs a lot of blue added to it and very little red and as the temperature climbs up, the amount of added red grows while the added blue goes down. | For our purposes, we are using individual color channel **gains** to compensate for a given temperature. Lower temperature "white light" needs a lot of blue added to it and very little red and as the temperature climbs up, the amount of added red grows while the added blue goes down. | ||
| ===== Color correction for white temperature ===== | ===== Color correction for white temperature ===== | ||
| - | 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 " | + | 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 " |
| 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 \(B = 4205.4 - T*0.4087\). | ||
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| ===== Practical example ===== | ===== Practical example ===== | ||
| - | What does all that mean in practice? Suppose you have set up your scene with " | + | What does all that mean in practice? Suppose you have set up your scene with " |
| See also [[Automatic white balance]] | See also [[Automatic white balance]] | ||