diff options
Diffstat (limited to 'src/ipa/rkisp1/algorithms/awb.cpp')
| -rw-r--r-- | src/ipa/rkisp1/algorithms/awb.cpp | 22 |
1 files changed, 15 insertions, 7 deletions
diff --git a/src/ipa/rkisp1/algorithms/awb.cpp b/src/ipa/rkisp1/algorithms/awb.cpp index 59664d09..a3066fbb 100644 --- a/src/ipa/rkisp1/algorithms/awb.cpp +++ b/src/ipa/rkisp1/algorithms/awb.cpp @@ -265,21 +265,29 @@ void Awb::process(IPAContext &context, frameContext.awb.temperatureK = estimateCCT(redMean, greenMean, blueMean); - /* Estimate the red and blue gains to apply in a grey world. */ + /* + * Estimate the red and blue gains to apply in a grey world. The green + * gain is hardcoded to 1.0. + */ double redGain = greenMean / (redMean + 1); double blueGain = greenMean / (blueMean + 1); + /* + * Clamp the gain values to the hardware, which expresses gains as Q2.8 + * unsigned integer values. Set the minimum just above zero to avoid + * divisions by zero when computing the raw means in subsequent + * iterations. + */ + redGain = std::clamp(redGain, 1.0 / 256, 1023.0 / 256); + blueGain = std::clamp(blueGain, 1.0 / 256, 1023.0 / 256); + /* Filter the values to avoid oscillations. */ double speed = 0.2; redGain = speed * redGain + (1 - speed) * activeState.awb.gains.automatic.red; blueGain = speed * blueGain + (1 - speed) * activeState.awb.gains.automatic.blue; - /* - * Gain values are unsigned integer value, range 0 to 4 with 8 bit - * fractional part. Hardcode the green gain to 1.0. - */ - activeState.awb.gains.automatic.red = std::clamp(redGain, 0.0, 1023.0 / 256); - activeState.awb.gains.automatic.blue = std::clamp(blueGain, 0.0, 1023.0 / 256); + activeState.awb.gains.automatic.red = redGain; + activeState.awb.gains.automatic.blue = blueGain; activeState.awb.gains.automatic.green = 1.0; LOG(RkISP1Awb, Debug) << std::showpoint |