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-rw-r--r--src/ipa/ipu3/algorithms/awb.cpp28
1 files changed, 26 insertions, 2 deletions
diff --git a/src/ipa/ipu3/algorithms/awb.cpp b/src/ipa/ipu3/algorithms/awb.cpp
index 4364928c..c5976c6f 100644
--- a/src/ipa/ipu3/algorithms/awb.cpp
+++ b/src/ipa/ipu3/algorithms/awb.cpp
@@ -19,6 +19,18 @@ LOG_DEFINE_CATEGORY(IPU3Awb)
static constexpr uint32_t kMinGreenLevelInZone = 32;
+/*
+ * Minimum proportion of non-saturated cells in a zone for the zone to be used
+ * by the AWB algorithm.
+ */
+static constexpr double kMaxCellSaturationRatio = 0.8;
+
+/*
+ * Maximum ratio of saturated pixels in a cell for the cell to be considered
+ * non-saturated and counted by the AWB algorithm.
+ */
+static constexpr uint32_t kMinCellsPerZoneRatio = 255 * 90 / 100;
+
/**
* \struct Accumulator
* \brief RGB statistics for a given zone
@@ -160,7 +172,8 @@ int Awb::configure(IPAContext &context,
* for it to be relevant for the grey world algorithm.
* \todo This proportion could be configured.
*/
- cellsPerZoneThreshold_ = cellsPerZoneX_ * cellsPerZoneY_ * 80 / 100;
+ cellsPerZoneThreshold_ = cellsPerZoneX_ * cellsPerZoneY_ * kMaxCellSaturationRatio;
+ LOG(IPU3Awb, Debug) << "Threshold for AWB is set to " << cellsPerZoneThreshold_;
return 0;
}
@@ -234,7 +247,18 @@ void Awb::generateAwbStats(const ipu3_uapi_stats_3a *stats)
reinterpret_cast<const ipu3_uapi_awb_set_item *>(
&stats->awb_raw_buffer.meta_data[cellPosition]
);
- if (currentCell->sat_ratio == 0) {
+
+ /*
+ * Use cells which have less than 90%
+ * saturation as an initial means to include
+ * otherwise bright cells which are not fully
+ * saturated.
+ *
+ * \todo The 90% saturation rate may require
+ * further empirical measurements and
+ * optimisation during camera tuning phases.
+ */
+ if (currentCell->sat_ratio <= kMinCellsPerZoneRatio) {
/* The cell is not saturated, use the current cell */
awbStats_[awbZonePosition].counted++;
uint32_t greenValue = currentCell->Gr_avg + currentCell->Gb_avg;