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authorJean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>2021-11-04 12:19:57 +0100
committerJean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>2021-11-15 10:49:13 +0100
commit5614c95794ddac82d5ff33e8b157f646214bf88d (patch)
treef04e5556c6c3f8a76615c118e065af3aa1b9b3d6
parent5233581e5194a87cada7b851921e655f769a8624 (diff)
ipa: ipu3: agc: Limit the number of saturated cells
When the histogram is calculated, we check if a cell is saturated or not before cumulating its green value. This is wrong, and it can lead to an empty histogram in case of a fully saturated frame. Use a constant to limit the amount of pixels within a cell before considering it saturated. If at the end of the loop we still have an empty histogram, then make it a fully saturated one. Bug: https://bugs.libcamera.org/show_bug.cgi?id=84 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>
-rw-r--r--src/ipa/ipu3/algorithms/agc.cpp16
1 files changed, 14 insertions, 2 deletions
diff --git a/src/ipa/ipu3/algorithms/agc.cpp b/src/ipa/ipu3/algorithms/agc.cpp
index 5723f6f3..83aa3676 100644
--- a/src/ipa/ipu3/algorithms/agc.cpp
+++ b/src/ipa/ipu3/algorithms/agc.cpp
@@ -63,6 +63,12 @@ static constexpr uint32_t knumHistogramBins = 256;
/* Target value to reach for the top 2% of the histogram */
static constexpr double kEvGainTarget = 0.5;
+/*
+ * Maximum ratio of saturated pixels in a cell for the cell to be considered
+ * non-saturated and counted by the AGC algorithm.
+ */
+static constexpr uint32_t kMinCellsPerZoneRatio = 255 * 20 / 100;
+
Agc::Agc()
: frameCount_(0), lastFrame_(0), iqMean_(0.0), lineDuration_(0s),
minExposureLines_(0), maxExposureLines_(0), filteredExposure_(0s),
@@ -124,7 +130,7 @@ void Agc::measureBrightness(const ipu3_uapi_stats_3a *stats,
&stats->awb_raw_buffer.meta_data[cellPosition]
);
- if (cell->sat_ratio == 0) {
+ if (cell->sat_ratio <= kMinCellsPerZoneRatio) {
uint8_t gr = cell->Gr_avg;
uint8_t gb = cell->Gb_avg;
/*
@@ -137,8 +143,14 @@ void Agc::measureBrightness(const ipu3_uapi_stats_3a *stats,
}
}
+ Histogram cumulativeHist = Histogram(Span<uint32_t>(hist));
/* Estimate the quantile mean of the top 2% of the histogram */
- iqMean_ = Histogram(Span<uint32_t>(hist)).interQuantileMean(0.98, 1.0);
+ if (cumulativeHist.total() == 0) {
+ /* Force the value as histogram is empty */
+ iqMean_ = knumHistogramBins - 0.5;
+ } else {
+ iqMean_ = cumulativeHist.interQuantileMean(0.98, 1.0);
+ }
}
/**