[PATCH 2/2] ipa: rkisp1: agc: Fix histogram construction

[Paul Elder]

The histogram reported by the rkisp1 hardware is 20 bits, where the
upper 16 bits are meaningful integer data and the lower 4 bits are
fractional and meant to be discarded. Remove these 4 bits when
constructing the histogram.

Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>
---
 src/ipa/rkisp1/algorithms/agc.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/ipa/rkisp1/algorithms/agc.cpp b/src/ipa/rkisp1/algorithms/agc.cpp
index 47a6f7b2..278903a5 100644
--- a/src/ipa/rkisp1/algorithms/agc.cpp
+++ b/src/ipa/rkisp1/algorithms/agc.cpp
@@ -352,7 +352,7 @@ double Agc::estimateLuminance(Span<const uint8_t> expMeans, double gain)
  */
 double Agc::measureBrightness(Span<const uint32_t> hist) const
 {
-	Histogram histogram{ hist };
+	Histogram histogram{ hist, 4 };
 	/* Estimate the quantile mean of the top 2% of the histogram. */
 	return histogram.interQuantileMean(0.98, 1.0);
 }
-- 
2.39.2