From 7fab2062d8274065e870de20382720a0cdb11193 Mon Sep 17 00:00:00 2001 From: Milan Zamazal Date: Fri, 27 Sep 2024 15:46:20 +0200 Subject: libcamera: software_isp: Move color handling to an algorithm module After black level handling has been moved to an algorithm module, white balance and the construction of color tables can be moved to algorithm modules too. This time, the moved code is split between stats processing and parameter construction methods. It is also split to two algorithm modules: - White balance computation. - Gamma table computation and color lookup tables construction. While this applies the color gains computed by the white balance algorithm, it is not directly related to white balance. And we may want to modify the color lookup tables in future according to other parameters than just gamma and white balance gains. Gamma table computation and color lookup tables construction could be split to separate algorithms too. But there is no big need for that now so they are kept together for simplicity. This is the only part of the software ISP algorithms that sets the parameters so emitting setIspParams can be moved to prepare() method. A more natural representation of the gains (and black level) would be floating point numbers. This is not done here in order to minimize changes in code movements. It will be addressed in a followup patch. Signed-off-by: Milan Zamazal Reviewed-by: Kieran Bingham Acked-by: Umang Jain Signed-off-by: Kieran Bingham --- src/ipa/simple/algorithms/awb.cpp | 70 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 70 insertions(+) create mode 100644 src/ipa/simple/algorithms/awb.cpp (limited to 'src/ipa/simple/algorithms/awb.cpp') diff --git a/src/ipa/simple/algorithms/awb.cpp b/src/ipa/simple/algorithms/awb.cpp new file mode 100644 index 00000000..3d76cc2f --- /dev/null +++ b/src/ipa/simple/algorithms/awb.cpp @@ -0,0 +1,70 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ +/* + * Copyright (C) 2024, Red Hat Inc. + * + * Auto white balance + */ + +#include "awb.h" + +#include +#include + +#include + +#include "simple/ipa_context.h" + +namespace libcamera { + +LOG_DEFINE_CATEGORY(IPASoftAwb) + +namespace ipa::soft::algorithms { + +int Awb::configure(IPAContext &context, + [[maybe_unused]] const IPAConfigInfo &configInfo) +{ + auto &gains = context.activeState.gains; + gains.red = gains.green = gains.blue = 256; + + return 0; +} + +void Awb::process(IPAContext &context, + [[maybe_unused]] const uint32_t frame, + [[maybe_unused]] IPAFrameContext &frameContext, + const SwIspStats *stats, + [[maybe_unused]] ControlList &metadata) +{ + const SwIspStats::Histogram &histogram = stats->yHistogram; + const uint8_t blackLevel = context.activeState.blc.level; + + /* + * Black level must be subtracted to get the correct AWB ratios, they + * would be off if they were computed from the whole brightness range + * rather than from the sensor range. + */ + const uint64_t nPixels = std::accumulate( + histogram.begin(), histogram.end(), 0); + const uint64_t offset = blackLevel * nPixels; + const uint64_t sumR = stats->sumR_ - offset / 4; + const uint64_t sumG = stats->sumG_ - offset / 2; + const uint64_t sumB = stats->sumB_ - offset / 4; + + /* + * Calculate red and blue gains for AWB. + * Clamp max gain at 4.0, this also avoids 0 division. + * Gain: 128 = 0.5, 256 = 1.0, 512 = 2.0, etc. + */ + auto &gains = context.activeState.gains; + gains.red = sumR <= sumG / 4 ? 1024 : 256 * sumG / sumR; + gains.blue = sumB <= sumG / 4 ? 1024 : 256 * sumG / sumB; + /* Green gain is fixed to 256 */ + + LOG(IPASoftAwb, Debug) << "gain R/B " << gains.red << "/" << gains.blue; +} + +REGISTER_IPA_ALGORITHM(Awb, "Awb") + +} /* namespace ipa::soft::algorithms */ + +} /* namespace libcamera */ -- cgit v1.2.1