diff options
Diffstat (limited to 'src/ipa/ipu3/algorithms/awb.cpp')
| -rw-r--r-- | src/ipa/ipu3/algorithms/awb.cpp | 78 |
1 files changed, 60 insertions, 18 deletions
diff --git a/src/ipa/ipu3/algorithms/awb.cpp b/src/ipa/ipu3/algorithms/awb.cpp index e05647c9..964d6995 100644 --- a/src/ipa/ipu3/algorithms/awb.cpp +++ b/src/ipa/ipu3/algorithms/awb.cpp @@ -21,26 +21,69 @@ static constexpr uint32_t kMinZonesCounted = 16; static constexpr uint32_t kMinGreenLevelInZone = 32; /** - * \struct IspStatsRegion - * \brief RGB statistics for a given region + * \struct Accumulator + * \brief RGB statistics for a given zone * - * The IspStatsRegion structure is intended to abstract the ISP specific - * statistics and use an agnostic algorithm to compute AWB. + * - Cells are defined in Pixels + * - Zones are defined in Cells * - * \var IspStatsRegion::counted - * \brief Number of pixels used to calculate the sums + * 80 cells + * /───────────── 1280 pixels ───────────\ + * 16 zones + * 16 + * ┌────┬────┬────┬────┬────┬─ ──────┬────┐ \ + * │Cell│ │ │ │ │ | │ │ │ + * 16 │ px │ │ │ │ │ | │ │ │ + * ├────┼────┼────┼────┼────┼─ ──────┼────┤ │ + * │ │ │ │ │ │ | │ │ + * │ │ │ │ │ │ | │ │ 7 + * │ ── │ ── │ ── │ ── │ ── │ ── ── ─┤ ── │ 1 2 4 + * │ │ │ │ │ │ | │ │ 2 0 5 * - * \var IspStatsRegion::uncounted - * \brief Remaining number of pixels in the region + * │ │ │ │ │ │ | │ │ z p c + * ├────┼────┼────┼────┼────┼─ ──────┼────┤ o i e + * │ │ │ │ │ │ | │ │ n x l + * │ │ | │ │ e e l + * ├─── ───┼─ ──────┼────┤ s l s + * │ │ | │ │ s + * │ │ | │ │ + * ├─── Zone of Cells ───┼─ ──────┼────┤ │ + * │ (5 x 4) │ | │ │ │ + * │ │ | │ │ │ + * ├── ───┼─ ──────┼────┤ │ + * │ │ │ | │ │ │ + * │ │ │ │ │ │ | │ │ │ + * └────┴────┴────┴────┴────┴─ ──────┴────┘ / * - * \var IspStatsRegion::rSum - * \brief Sum of the red values in the region * - * \var IspStatsRegion::gSum - * \brief Sum of the green values in the region + * The algorithm works with a fixed number of zones \a kAwbStatsSizeX x + * \a kAwbStatsSizeY. For example, a frame of 1280x720 is divided into 80x45 + * cells of [16x16] pixels. In the case of \a kAwbStatsSizeX=16 and + * \a kAwbStatsSizeY=12 the zones are made of [5x4] cells. The cells are + * left-aligned and calculated by IPAIPU3::calculateBdsGrid(). * - * \var IspStatsRegion::bSum - * \brief Sum of the blue values in the region + * Each statistics cell represents the average value of the pixels in that cell + * split by colour components. + * + * The Accumulator structure stores the sum of the average of each cell in a + * zone of the image, as well as the number of cells which were unsaturated and + * therefore included in the average. + * \todo move this description and structure into a common header + * + * Cells which are saturated beyond the threshold defined in + * ipu3_uapi_awb_config_s are not included in the average. + * + * \var Accumulator::counted + * \brief Number of unsaturated cells used to calculate the sums + * + * \var Accumulator::rSum + * \brief Sum of the average red values of each unsaturated cell in the zone + * + * \var Accumulator::gSum + * \brief Sum of the average green values of each unsaturated cell in the zone + * + * \var Accumulator::bSum + * \brief Sum of the average blue values of each unsaturated cell in the zone */ /** @@ -157,7 +200,7 @@ uint32_t Awb::estimateCCT(double red, double green, double blue) return 449 * n * n * n + 3525 * n * n + 6823.3 * n + 5520.33; } -/* Generate an RGB vector with the average values for each region */ +/* Generate an RGB vector with the average values for each zone */ void Awb::generateZones(std::vector<RGB> &zones) { for (unsigned int i = 0; i < kAwbStatsSizeX * kAwbStatsSizeY; i++) { @@ -174,7 +217,7 @@ void Awb::generateZones(std::vector<RGB> &zones) } } -/* Translate the IPU3 statistics into the default statistics region array */ +/* Translate the IPU3 statistics into the default statistics zone array */ void Awb::generateAwbStats(const ipu3_uapi_stats_3a *stats, const ipu3_uapi_grid_config &grid) { @@ -215,7 +258,6 @@ void Awb::clearAwbStats() awbStats_[i].rSum = 0; awbStats_[i].gSum = 0; awbStats_[i].counted = 0; - awbStats_[i].uncounted = 0; } } @@ -304,7 +346,7 @@ void Awb::prepare(IPAContext &context, ipu3_uapi_params *params) /* * Optical center is column start (respectively row start) of the - * region of interest minus its X center (respectively Y center). + * cell of interest minus its X center (respectively Y center). * * For the moment use BDS as a first approximation, but it should * be calculated based on Shading (SHD) parameters. |