[libcamera-devel,v4,10/14] ipa: ipu3: agc: Rename gains properly
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Message ID 20211022073249.35084-11-jeanmichel.hautbois@ideasonboard.com
State Accepted
Commit fd5a82ea880908f2dc99e730e91cbe2cc6ce0327
Headers show
Series
  • ipa: ipu3: Fix AGC bugs
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Commit Message

Jean-Michel Hautbois Oct. 22, 2021, 7:32 a.m. UTC 
We have mixed terms between gain, analogue gain and the exposure value
gain.

Make it clear when we are using the analogue gain from the sensor, and
when we are using the calculated gain to be applied to the exposure
value to reach the target.

Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
---
 src/ipa/ipu3/algorithms/agc.cpp | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

Patch
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diff --git a/src/ipa/ipu3/algorithms/agc.cpp b/src/ipa/ipu3/algorithms/agc.cpp
index 6f5b6a45..e7c59f3d 100644
--- a/src/ipa/ipu3/algorithms/agc.cpp
+++ b/src/ipa/ipu3/algorithms/agc.cpp
@@ -125,7 +125,7 @@  void Agc::filterExposure()
 	LOG(IPU3Agc, Debug) << "After filtering, total_exposure " << filteredExposure_;
 }
 
-void Agc::lockExposureGain(uint32_t &exposure, double &gain)
+void Agc::lockExposureGain(uint32_t &exposure, double &analogueGain)
 {
 	/* Algorithm initialization should wait for first valid frames */
 	/* \todo - have a number of frames given by DelayedControls ?
@@ -137,16 +137,17 @@  void Agc::lockExposureGain(uint32_t &exposure, double &gain)
 	if (std::abs(iqMean_ - kEvGainTarget * knumHistogramBins) <= 1) {
 		LOG(IPU3Agc, Debug) << "!!! Good exposure with iqMean = " << iqMean_;
 	} else {
-		double newGain = kEvGainTarget * knumHistogramBins / iqMean_;
+		double evGain = kEvGainTarget * knumHistogramBins / iqMean_;
 
 		/* extracted from Rpi::Agc::computeTargetExposure */
 		utils::Duration currentShutter = exposure * lineDuration_;
-		currentExposureNoDg_ = currentShutter * gain;
+		currentExposureNoDg_ = currentShutter * analogueGain;
 		LOG(IPU3Agc, Debug) << "Actual total exposure " << currentExposureNoDg_
 				    << " Shutter speed " << currentShutter
-				    << " Gain " << gain;
+				    << " Gain " << analogueGain
+				    << " Needed ev gain " << evGain;
 
-		currentExposure_ = currentExposureNoDg_ * newGain;
+		currentExposure_ = currentExposureNoDg_ * evGain;
 		utils::Duration minShutterSpeed = minExposureLines_ * lineDuration_;
 		utils::Duration maxShutterSpeed = maxExposureLines_ * lineDuration_;
 
@@ -174,7 +175,7 @@  void Agc::lockExposureGain(uint32_t &exposure, double &gain)
 				    << stepGain;
 
 		exposure = shutterTime / lineDuration_;
-		gain = stepGain;
+		analogueGain = stepGain;
 	}
 	lastFrame_ = frameCount_;
 }
@@ -182,9 +183,9 @@  void Agc::lockExposureGain(uint32_t &exposure, double &gain)
 void Agc::process(IPAContext &context, const ipu3_uapi_stats_3a *stats)
 {
 	uint32_t &exposure = context.frameContext.agc.exposure;
-	double &gain = context.frameContext.agc.gain;
+	double &analogueGain = context.frameContext.agc.gain;
 	processBrightness(stats, context.configuration.grid.bdsGrid);
-	lockExposureGain(exposure, gain);
+	lockExposureGain(exposure, analogueGain);
 	frameCount_++;
 }