[libcamera-devel] [PATCH v2 5/5] ipa: raspberrypi: Normalise region sums to 16-bits
Naushir Patuck
naush at raspberrypi.com
Thu Nov 24 11:38:32 CET 2022
The VC4 ISP uses a pipeline bit-depth of 13-bits. The AGC algorithm needs to
know this bit-depth when computing the Y value for the image.
Instead of hardcoding the VC4 bit-depth in the AGC source code, normalise all
region sums to 16-bits when filling the Statistics structure. AWB and ALSC are
agnostic about pipeline depth, so do not need changing.
Signed-off-by: Naushir Patuck <naush at raspberrypi.com>
Reviewed-by: David Plowman <david.plowman at raspberrypi.com>
---
src/ipa/raspberrypi/controller/rpi/agc.cpp | 10 ++++------
src/ipa/raspberrypi/raspberrypi.cpp | 16 ++++++++++------
2 files changed, 14 insertions(+), 12 deletions(-)
diff --git a/src/ipa/raspberrypi/controller/rpi/agc.cpp b/src/ipa/raspberrypi/controller/rpi/agc.cpp
index a7f0e954407d..e400e478162f 100644
--- a/src/ipa/raspberrypi/controller/rpi/agc.cpp
+++ b/src/ipa/raspberrypi/controller/rpi/agc.cpp
@@ -28,8 +28,6 @@ LOG_DEFINE_CATEGORY(RPiAgc)
#define NAME "rpi.agc"
-static constexpr unsigned int PipelineBits = 13; /* seems to be a 13-bit pipeline */
-
int AgcMeteringMode::read(const libcamera::YamlObject ¶ms)
{
const YamlObject &yamlWeights = params["weights"];
@@ -592,9 +590,9 @@ static double computeInitialY(StatisticsPtr &stats, AwbStatus const &awb,
double rSum = 0, gSum = 0, bSum = 0, pixelSum = 0;
for (unsigned int i = 0; i < stats->agcRegions.numRegions(); i++) {
auto ®ion = stats->agcRegions.get(i);
- double rAcc = std::min<double>(region.val.rSum * gain, ((1 << PipelineBits) - 1) * region.counted);
- double gAcc = std::min<double>(region.val.gSum * gain, ((1 << PipelineBits) - 1) * region.counted);
- double bAcc = std::min<double>(region.val.bSum * gain, ((1 << PipelineBits) - 1) * region.counted);
+ double rAcc = std::min<double>(region.val.rSum * gain, ((1 << 16) - 1) * region.counted);
+ double gAcc = std::min<double>(region.val.gSum * gain, ((1 << 16) - 1) * region.counted);
+ double bAcc = std::min<double>(region.val.bSum * gain, ((1 << 16) - 1) * region.counted);
rSum += rAcc * weights[i];
gSum += gAcc * weights[i];
bSum += bAcc * weights[i];
@@ -607,7 +605,7 @@ static double computeInitialY(StatisticsPtr &stats, AwbStatus const &awb,
double ySum = rSum * awb.gainR * .299 +
gSum * awb.gainG * .587 +
bSum * awb.gainB * .114;
- return ySum / pixelSum / (1 << PipelineBits);
+ return ySum / pixelSum / (1 << 16);
}
/*
diff --git a/src/ipa/raspberrypi/raspberrypi.cpp b/src/ipa/raspberrypi/raspberrypi.cpp
index 44527357243d..ac1875d203ae 100644
--- a/src/ipa/raspberrypi/raspberrypi.cpp
+++ b/src/ipa/raspberrypi/raspberrypi.cpp
@@ -1132,11 +1132,15 @@ RPiController::StatisticsPtr IPARPi::fillStatistics(bcm2835_isp_stats *stats) co
/* RGB histograms are not used, so do not populate them. */
statistics->yHist = std::move(RPiController::Histogram(stats->hist[0].g_hist, NUM_HISTOGRAM_BINS));
+ /*
+ * All region sums are based on a 13-bit pipeline bit-depth. Normalise
+ * this to 16-bits for the AGC/AWB/ALSC algorithms.
+ */
statistics->awbRegions.init({ DEFAULT_AWB_REGIONS_X, DEFAULT_AWB_REGIONS_Y });
for (i = 0; i < statistics->awbRegions.numRegions(); i++)
- statistics->awbRegions.set(i, { { stats->awb_stats[i].r_sum,
- stats->awb_stats[i].g_sum,
- stats->awb_stats[i].b_sum },
+ statistics->awbRegions.set(i, { { stats->awb_stats[i].r_sum << 3,
+ stats->awb_stats[i].g_sum << 3,
+ stats->awb_stats[i].b_sum << 3 },
stats->awb_stats[i].counted,
stats->awb_stats[i].notcounted });
@@ -1146,9 +1150,9 @@ RPiController::StatisticsPtr IPARPi::fillStatistics(bcm2835_isp_stats *stats) co
*/
statistics->agcRegions.init(15);
for (i = 0; i < statistics->agcRegions.numRegions(); i++)
- statistics->agcRegions.set(i, { { stats->agc_stats[i].r_sum,
- stats->agc_stats[i].g_sum,
- stats->agc_stats[i].b_sum },
+ statistics->agcRegions.set(i, { { stats->agc_stats[i].r_sum << 3,
+ stats->agc_stats[i].g_sum << 3,
+ stats->agc_stats[i].b_sum << 3 },
stats->agc_stats[i].counted,
stats->awb_stats[i].notcounted });
--
2.25.1
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