[libcamera-devel] [PATCH v2 11/12] ipa: ipu3: agc: Rewrite and simplify the brightness loop
Kieran Bingham
kieran.bingham at ideasonboard.com
Thu Sep 30 17:17:27 CEST 2021
On 30/09/2021 10:37, Jean-Michel Hautbois wrote:
> Now that we know how the AWB statistics are formatted, use a simplified
> loop in processBrightness() to parse the green values and get the
> histogram.
>
> Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois at ideasonboard.com>
> ---
> src/ipa/ipu3/algorithms/agc.cpp | 55 ++++++++++++---------------------
> src/ipa/ipu3/algorithms/agc.h | 2 ++
> 2 files changed, 22 insertions(+), 35 deletions(-)
>
> diff --git a/src/ipa/ipu3/algorithms/agc.cpp b/src/ipa/ipu3/algorithms/agc.cpp
> index 5ff50f4a..46e01fc4 100644
> --- a/src/ipa/ipu3/algorithms/agc.cpp
> +++ b/src/ipa/ipu3/algorithms/agc.cpp
> @@ -6,6 +6,7 @@
> */
>
> #include "agc.h"
> +#include "awb.h"
>
> #include <algorithm>
> #include <chrono>
> @@ -47,9 +48,6 @@ static constexpr uint32_t kMaxExposure = 1976;
> static constexpr uint32_t knumHistogramBins = 256;
> static constexpr double kEvGainTarget = 0.5;
>
> -/* A cell is 8 bytes and contains averages for RGB values and saturation ratio */
> -static constexpr uint8_t kCellSize = 8;
> -
> Agc::Agc()
> : frameCount_(0), lastFrame_(0), iqMean_(0.0), lineDuration_(0s),
> maxExposureTime_(0s), prevExposure_(0s), prevExposureNoDg_(0s),
> @@ -57,9 +55,10 @@ Agc::Agc()
> {
> }
>
> -int Agc::configure([[maybe_unused]] IPAContext &context,
> - const IPAConfigInfo &configInfo)
> +int Agc::configure(IPAContext &context, const IPAConfigInfo &configInfo)
> {
> + stride_ = context.configuration.grid.stride;
> +
> lineDuration_ = configInfo.sensorInfo.lineLength * 1.0s
> / configInfo.sensorInfo.pixelRate;
> maxExposureTime_ = kMaxExposure * lineDuration_;
> @@ -70,37 +69,23 @@ int Agc::configure([[maybe_unused]] IPAContext &context,
> void Agc::processBrightness(const ipu3_uapi_stats_3a *stats,
> const ipu3_uapi_grid_config &grid)
> {
> - const struct ipu3_uapi_grid_config statsAeGrid = stats->stats_4a_config.awb_config.grid;
> - Rectangle aeRegion = { statsAeGrid.x_start,
> - statsAeGrid.y_start,
> - static_cast<unsigned int>(statsAeGrid.x_end - statsAeGrid.x_start) + 1,
> - static_cast<unsigned int>(statsAeGrid.y_end - statsAeGrid.y_start) + 1 };
> - Point topleft = aeRegion.topLeft();
> - int topleftX = topleft.x >> grid.block_width_log2;
> - int topleftY = topleft.y >> grid.block_height_log2;
> -
> - /* Align to the grid cell width and height */
> - uint32_t startX = topleftX << grid.block_width_log2;
> - uint32_t startY = topleftY * grid.width << grid.block_width_log2;
> - uint32_t endX = (startX + (aeRegion.size().width >> grid.block_width_log2)) << grid.block_width_log2;
> - uint32_t i, j;
> - uint32_t count = 0;
> -
> uint32_t hist[knumHistogramBins] = { 0 };
> - for (j = topleftY;
> - j < topleftY + (aeRegion.size().height >> grid.block_height_log2);
> - j++) {
> - for (i = startX + startY; i < endX + startY; i += kCellSize) {
> - /*
> - * The grid width (and maybe height) is not reliable.
> - * We observed a bit shift which makes the value 160 to be 32 in the stats grid.
> - * Use the one passed at init time.
> - */
> - if (stats->awb_raw_buffer.meta_data[i + 4 + j * grid.width] == 0) {
> - uint8_t Gr = stats->awb_raw_buffer.meta_data[i + 0 + j * grid.width];
> - uint8_t Gb = stats->awb_raw_buffer.meta_data[i + 3 + j * grid.width];
> - hist[(Gr + Gb) / 2]++;
> - count++;
> +
> + for (unsigned int cellY = 0; cellY < grid.height; cellY++) {
> + for (unsigned int cellX = 0; cellX < grid.width; cellX++) {
> + uint32_t cellPosition = cellY * stride_ + cellX
> + * sizeof(Ipu3AwbCell);
> +
> + /* Cast the initial IPU3 structure to simplify the reading */
I'm not sure that comment adds much, but it doesn't hurt anything.
Stride issues are all fixed up, and I think the Ipu3AwbCell gets changed
to the new structure in the next patch...
Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> + const Ipu3AwbCell *cell =
> + reinterpret_cast<const Ipu3AwbCell *>(
> + &stats->awb_raw_buffer.meta_data[cellPosition]
> + );
> +
> + if (cell->satRatio == 0) {
> + uint8_t gr = cell->greenRedAvg;
> + uint8_t gb = cell->greenBlueAvg;
> + hist[(gr + gb) / 2]++;
> }
> }
> }
> diff --git a/src/ipa/ipu3/algorithms/agc.h b/src/ipa/ipu3/algorithms/agc.h
> index e36797d3..64b71c65 100644
> --- a/src/ipa/ipu3/algorithms/agc.h
> +++ b/src/ipa/ipu3/algorithms/agc.h
> @@ -50,6 +50,8 @@ private:
> Duration prevExposureNoDg_;
> Duration currentExposure_;
> Duration currentExposureNoDg_;
> +
> + uint32_t stride_;
> };
>
> } /* namespace ipa::ipu3::algorithms */
>
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