diff options
| author | Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com> | 2021-11-04 12:19:57 +0100 |
|---|---|---|
| committer | Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com> | 2021-11-15 10:49:13 +0100 |
| commit | 5614c95794ddac82d5ff33e8b157f646214bf88d (patch) | |
| tree | f04e5556c6c3f8a76615c118e065af3aa1b9b3d6 | |
| parent | 5233581e5194a87cada7b851921e655f769a8624 (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.cpp | 16 |
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); + } } /** |