| Message ID | 20211111140928.136111-5-jeanmichel.hautbois@ideasonboard.com |
|---|---|
| State | Accepted |
| Headers | show |
| Series |
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| Related | show |
Hi Jean-Michel, On Thu, Nov 11, 2021 at 03:09:18PM +0100, Jean-Michel Hautbois wrote: > 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> > --- > src/ipa/ipu3/algorithms/agc.cpp | 16 ++++++++++++++-- > 1 file 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); > + } > } > > /** > -- > 2.32.0 >
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); + } } /**