[libcamera-devel,v5,06/14] ipa: ipu3: agc: Refactor ev gain calculation and testing
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Message ID 20211113084947.21892-7-jeanmichel.hautbois@ideasonboard.com
State Accepted
Headers show
Series
  • IPA: IPU3: Introduce per-frame controls
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Commit Message

Jean-Michel Hautbois Nov. 13, 2021, 8:49 a.m. UTC 
When we compute the new gain, we use the iqMean_ and estimate an
exposure value gain to apply. Return early when the gain is less than
1%.

Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
---
 src/ipa/ipu3/algorithms/agc.cpp | 14 ++++++--------
 1 file changed, 6 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 74bce7bb..61ca8b3f 100644
--- a/src/ipa/ipu3/algorithms/agc.cpp
+++ b/src/ipa/ipu3/algorithms/agc.cpp
@@ -188,14 +188,6 @@  void Agc::filterExposure()
  */
 void Agc::computeExposure(IPAFrameContext &frameContext)
 {
-
-	/* Are we correctly exposed ? */
-	if (std::abs(iqMean_ - kEvGainTarget * knumHistogramBins) <= 1) {
-		LOG(IPU3Agc, Debug) << "We are well exposed (iqMean = "
-				    << iqMean_ << ")";
-		return;
-	}
-
 	/* Get the effective exposure and gain applied on the sensor. */
 	uint32_t exposure = frameContext.sensor.exposure;
 	double analogueGain = frameContext.sensor.gain;
@@ -203,6 +195,12 @@  void Agc::computeExposure(IPAFrameContext &frameContext)
 	/* Estimate the gain needed to have the proportion wanted */
 	double evGain = kEvGainTarget * knumHistogramBins / iqMean_;
 
+	if (std::abs(evGain - 1.0) < 0.01) {
+		LOG(IPU3Agc, Debug) << "We are well exposed (iqMean = "
+				    << iqMean_ << ")";
+		return;
+	}
+
 	/* extracted from Rpi::Agc::computeTargetExposure */
 	/* Calculate the shutter time in seconds */
 	utils::Duration currentShutter = exposure * lineDuration_;