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ipa: ipu3: agc: Store exposure in units of time

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The minimum and maximum exposure are stored in lines. Replace it by
values in time to simplify the calculations.

Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Umang Jain <umang.jain@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
This commit is contained in:
Jean-Michel Hautbois 2021-11-04 18:22:46 +01:00
parent 93af8ea616
commit 891ec3f872
2 changed files with 11 additions and 14 deletions
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21
src/ipa/ipu3/algorithms/agc.cpp
View file

@ -79,8 +79,8 @@ static constexpr uint32_t kMaxLuminance = 255;
static constexpr double kNormalizedLumaTarget = 0.16;
Agc::Agc()
: frameCount_(0), iqMean_(0.0), lineDuration_(0s), minExposureLines_(0),
maxExposureLines_(0), filteredExposure_(0s), currentExposure_(0s)
: frameCount_(0), iqMean_(0.0), lineDuration_(0s), minShutterSpeed_(0s),
maxShutterSpeed_(0s), filteredExposure_(0s), currentExposure_(0s)
{
}
@ -99,17 +99,16 @@ int Agc::configure(IPAContext &context, const IPAConfigInfo &configInfo)
lineDuration_ = configInfo.sensorInfo.lineLength * 1.0s
/ configInfo.sensorInfo.pixelRate;
/* \todo replace the exposure in lines storage with time based ones. */
minExposureLines_ = context.configuration.agc.minShutterSpeed / lineDuration_;
maxExposureLines_ = std::min(context.configuration.agc.maxShutterSpeed / lineDuration_,
kMaxShutterSpeed / lineDuration_);
minShutterSpeed_ = context.configuration.agc.minShutterSpeed;
maxShutterSpeed_ = std::min(context.configuration.agc.maxShutterSpeed,
kMaxShutterSpeed);
minAnalogueGain_ = std::max(context.configuration.agc.minAnalogueGain, kMinAnalogueGain);
maxAnalogueGain_ = std::min(context.configuration.agc.maxAnalogueGain, kMaxAnalogueGain);
/* Configure the default exposure and gain. */
context.frameContext.agc.gain = minAnalogueGain_;
context.frameContext.agc.exposure = minExposureLines_;
context.frameContext.agc.exposure = minShutterSpeed_ / lineDuration_;
return 0;
}
@ -236,11 +235,9 @@ void Agc::computeExposure(IPAFrameContext &frameContext, double currentYGain)
* exposure value applied multiplied by the new estimated gain.
*/
currentExposure_ = effectiveExposureValue * evGain;
utils::Duration minShutterSpeed = minExposureLines_ * lineDuration_;
utils::Duration maxShutterSpeed = maxExposureLines_ * lineDuration_;
/* Clamp the exposure value to the min and max authorized */
utils::Duration maxTotalExposure = maxShutterSpeed * maxAnalogueGain_;
utils::Duration maxTotalExposure = maxShutterSpeed_ * maxAnalogueGain_;
currentExposure_ = std::min(currentExposure_, maxTotalExposure);
LOG(IPU3Agc, Debug) << "Target total exposure " << currentExposure_
<< ", maximum is " << maxTotalExposure;
@ -250,14 +247,14 @@ void Agc::computeExposure(IPAFrameContext &frameContext, double currentYGain)
/* Divide the exposure value as new exposure and gain values */
utils::Duration exposureValue = filteredExposure_;
utils::Duration shutterTime = minShutterSpeed;
utils::Duration shutterTime;
/*
* Push the shutter time up to the maximum first, and only then
* increase the gain.
*/
shutterTime = std::clamp<utils::Duration>(exposureValue / minAnalogueGain_,
minShutterSpeed, maxShutterSpeed);
minShutterSpeed_, maxShutterSpeed_);
double stepGain = std::clamp(exposureValue / shutterTime,
minAnalogueGain_, maxAnalogueGain_);
LOG(IPU3Agc, Debug) << "Divided up shutter and gain are "

4
src/ipa/ipu3/algorithms/agc.h
View file

@ -45,8 +45,8 @@ private:
double iqMean_;
utils::Duration lineDuration_;
uint32_t minExposureLines_;
uint32_t maxExposureLines_;
utils::Duration minShutterSpeed_;
utils::Duration maxShutterSpeed_;
double minAnalogueGain_;
double maxAnalogueGain_;