[libcamera-devel,v4,07/14] ipa: ipu3: agc: Change analogue gain limits
diff mbox series

Message ID 20211022073249.35084-8-jeanmichel.hautbois@ideasonboard.com
State Accepted
Commit a58a784e53f4c350a912aa36a1103ee2f259aedb
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Series
  • ipa: ipu3: Fix AGC bugs
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Commit Message

Jean-Michel Hautbois Oct. 22, 2021, 7:32 a.m. UTC 
The gains are currently set as a uint32_t while the analogue gain is
passed as a double. We also have a default maximum analogue gain of 15
which is quite high for a number of sensors.

Use a maximum value of 8 which should really be configured by the IPA
and not fixed as it is now. While at it make it a double.

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 | 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 58872410..984aed53 100644
--- a/src/ipa/ipu3/algorithms/agc.cpp
+++ b/src/ipa/ipu3/algorithms/agc.cpp
@@ -30,14 +30,10 @@  static constexpr uint32_t kInitialFrameMinAECount = 4;
 /* Number of frames to wait between new gain/exposure estimations */
 static constexpr uint32_t kFrameSkipCount = 6;
 
-/* Maximum ISO value for analogue gain */
-static constexpr uint32_t kMinISO = 100;
-static constexpr uint32_t kMaxISO = 1500;
-
 /* Maximum analogue gain value
  * \todo grab it from a camera helper */
-static constexpr uint32_t kMinGain = kMinISO / 100;
-static constexpr uint32_t kMaxGain = kMaxISO / 100;
+static constexpr double kMinGain = 1.0;
+static constexpr double kMaxGain = 8.0;
 
 /* Histogram constants */
 static constexpr uint32_t knumHistogramBins = 256;
@@ -166,9 +162,11 @@  void Agc::lockExposureGain(uint32_t &exposure, double &gain)
 							minExposureLines_,
 							maxExposureLines_);
 			newExposure = currentExposure_ / exposure;
-			gain = std::clamp(static_cast<uint32_t>(gain * currentExposure_ / newExposure), kMinGain, kMaxGain);
+			gain = std::clamp(gain * currentExposure_ / newExposure,
+					  kMinGain, kMaxGain);
 		} else {
-			gain = std::clamp(static_cast<uint32_t>(gain * currentExposure_ / currentExposureNoDg_), kMinGain, kMaxGain);
+			gain = std::clamp(gain * currentExposure_ / currentExposureNoDg_,
+					  kMinGain, kMaxGain);
 			newExposure = currentExposure_ / gain;
 			exposure = std::clamp<uint32_t>(exposure * currentExposure_ / newExposure,
 							minExposureLines_,