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ipa: raspberrypi: Normalise region sums to 16-bits

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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@raspberrypi.com>
Reviewed-by: David Plowman <david.plowman@raspberrypi.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
This commit is contained in:
Naushir Patuck 2023-02-03 09:17:34 +00:00 • committed by Kieran Bingham
parent 6d60f264d1
commit 61b43e50e7
2 changed files with 17 additions and 12 deletions
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18
src/ipa/raspberrypi/raspberrypi.cpp
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@ -1377,11 +1377,17 @@ RPiController::StatisticsPtr IPARPi::fillStatistics(bcm2835_isp_stats *stats) co
/* RGB histograms are not used, so do not populate them. */
statistics->yHist = 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.
*/
constexpr unsigned int scale = Statistics::NormalisationFactorPow2 - 13;
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 << scale,
stats->awb_stats[i].g_sum << scale,
stats->awb_stats[i].b_sum << scale },
stats->awb_stats[i].counted,
stats->awb_stats[i].notcounted });
@ -1391,9 +1397,9 @@ 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 << scale,
stats->agc_stats[i].g_sum << scale,
stats->agc_stats[i].b_sum << scale },
stats->agc_stats[i].counted,
stats->awb_stats[i].notcounted });