[libcamera-devel] [PATCH v2 4/4] ipa: rkisp1: Introduce AWB
Jean-Michel Hautbois
jeanmichel.hautbois at ideasonboard.com
Thu Feb 24 09:11:14 CET 2022
Hi Laurent,
On 24/02/2022 08:13, Laurent Pinchart wrote:
> Hi Jean-Michel,
>
> Thank you for the patch.
>
> On Wed, Feb 23, 2022 at 11:48:24AM +0100, Jean-Michel Hautbois wrote:
>> The RkISP1 ISP calculates a mean value for Y, Cr and Cb at each frame.
>> There is a RGB mode which could theoretically give us the values for R,
>> G and B directly, but it seems to be failing right now.
>>
>> Convert those values into R, G and B and estimate the gain to apply in a
>> grey world.
>>
>> Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois at ideasonboard.com>
>> Tested-by: Peter Griffin <peter.griffin at linaro.org>
>> ---
>> src/ipa/rkisp1/algorithms/awb.cpp | 155 ++++++++++++++++++++++++++
>> src/ipa/rkisp1/algorithms/awb.h | 33 ++++++
>> src/ipa/rkisp1/algorithms/meson.build | 1 +
>> src/ipa/rkisp1/ipa_context.cpp | 28 +++++
>> src/ipa/rkisp1/ipa_context.h | 16 +++
>> src/ipa/rkisp1/rkisp1.cpp | 2 +
>> 6 files changed, 235 insertions(+)
>> create mode 100644 src/ipa/rkisp1/algorithms/awb.cpp
>> create mode 100644 src/ipa/rkisp1/algorithms/awb.h
>>
>> diff --git a/src/ipa/rkisp1/algorithms/awb.cpp b/src/ipa/rkisp1/algorithms/awb.cpp
>> new file mode 100644
>> index 00000000..8fa8c2f7
>> --- /dev/null
>> +++ b/src/ipa/rkisp1/algorithms/awb.cpp
>> @@ -0,0 +1,155 @@
>> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
>> +/*
>> + * Copyright (C) 2021, Ideas On Board
>
> 2021-2022
>
> Time flies :-)
Thanks, I will apply it on all the other files too then ;-).
>
>> + *
>> + * awb.cpp - AWB control algorithm
>> + */
>> +
>> +#include "awb.h"
>> +
>> +#include <algorithm>
>> +#include <cmath>
>> +
>> +#include <libcamera/base/log.h>
>> +
>> +#include <libcamera/ipa/core_ipa_interface.h>
>> +
>> +/**
>> + * \file awb.h
>> + */
>> +
>> +namespace libcamera {
>> +
>> +namespace ipa::rkisp1::algorithms {
>> +
>> +/**
>> + * \class Awb
>> + * \brief A Grey world white balance correction algorithm
>> + */
>> +
>> +LOG_DEFINE_CATEGORY(RkISP1Awb)
>> +
>> +/**
>> + * \copydoc libcamera::ipa::Algorithm::configure
>> + */
>> +int Awb::configure(IPAContext &context,
>> + const IPACameraSensorInfo &configInfo)
>> +{
>> + context.frameContext.awb.gains.red = 1.0;
>> + context.frameContext.awb.gains.blue = 1.0;
>> + context.frameContext.awb.gains.green = 1.0;
>> +
>> + /* Define the measurement window for AGC. */
>
> Same comment as for patch 3/4.
>
>> + context.configuration.awb.measureWindow.h_offs = configInfo.outputSize.width / 8;
>> + context.configuration.awb.measureWindow.v_offs = configInfo.outputSize.height / 8;
>> + context.configuration.awb.measureWindow.h_size = 3 * configInfo.outputSize.width / 4;
>> + context.configuration.awb.measureWindow.v_size = 3 * configInfo.outputSize.height / 4;
>> +
>> + return 0;
>> +}
>> +
>> +uint32_t Awb::estimateCCT(double red, double green, double blue)
>> +{
>> + /* Convert the RGB values to CIE tristimulus values (XYZ) */
>> + double X = (-0.14282) * (red) + (1.54924) * (green) + (-0.95641) * (blue);
>> + double Y = (-0.32466) * (red) + (1.57837) * (green) + (-0.73191) * (blue);
>> + double Z = (-0.68202) * (red) + (0.77073) * (green) + (0.56332) * (blue);
>> +
>> + /* Calculate the normalized chromaticity values */
>> + double x = X / (X + Y + Z);
>> + double y = Y / (X + Y + Z);
>> +
>> + /* Calculate CCT */
>> + double n = (x - 0.3320) / (0.1858 - y);
>> + return 449 * n * n * n + 3525 * n * n + 6823.3 * n + 5520.33;
>> +}
>> +
>> +/**
>> + * \copydoc libcamera::ipa::Algorithm::process
>> + */
>> +void Awb::process([[maybe_unused]] IPAContext &context, const rkisp1_stat_buffer *stats)
>
> Please move this after prepare() to match the order of the .h file.
>
>> +{
>> + const rkisp1_cif_isp_stat *params = &stats->params;
>> + const rkisp1_cif_isp_awb_stat *awb = ¶ms->awb;
>> +
>> + /* Get the YCbCr mean values */
>> + double yMean = awb->awb_mean[0].mean_y_or_g;
>> + double crMean = awb->awb_mean[0].mean_cr_or_r;
>> + double cbMean = awb->awb_mean[0].mean_cb_or_b;
>> +
>> + /* Convert from YCbCr to RGB. */
>> + double redMean = yMean + 1.402 * (crMean - 128);
>> + double blueMean = yMean + 1.772 * (cbMean - 128);
>> + double greenMean = yMean - 0.34414 * (cbMean - 128) - 0.71414 * (crMean - 128);
>
> Where do those values come from ? Unless I'm mistaken, the hardware uses
> the following formulas to convert from RGB to YCbCr.
>
> Y = 16 + 0.2500 R + 0.5000 G + 0.1094 B
> Cb = 128 - 0.1406 R - 0.2969 G + 0.4375 B
> Cr = 128 + 0.4375 R - 0.3750 G - 0.0625 B
>
I took the JPEG File Interchange Format conversion formula, and not the
inverse matrix of the one the HW is using indeed.
I will need to calculate it then (keeping in mind that I convert from
YCrCb because the RGB mode is not working -yet- )...
>> +
>> + /* Estimate the red and blue gains to apply in a grey world. */
>> + double redGain = greenMean / (redMean + 1);
>> + double blueGain = greenMean / (blueMean + 1);
>> +
>> + /* Filter the values to avoid oscillations. */
>> + IPAFrameContext &frameContext = context.frameContext;
>> +
>> + frameContext.awb.temperatureK = estimateCCT(redMean, greenMean, blueMean);
>> + frameContext.awb.gains.red = 0.2 * redGain +
>> + 0.8 * frameContext.awb.gains.red;
>> + frameContext.awb.gains.blue = 0.2 * blueGain +
>> + 0.8 * frameContext.awb.gains.blue;
>
> Don't you need to saturate the gains, either here, or in prepare() ?
>
>> + /* Hardcode the green gain to 1.0. */
>> + frameContext.awb.gains.green = 1.0;
>> +
>> + LOG(RkISP1Awb, Debug) << "Gain found for red: " << context.frameContext.awb.gains.red
>> + << " and for blue: " << context.frameContext.awb.gains.blue;
>> +}
>> +
>> +/**
>> + * \copydoc libcamera::ipa::Algorithm::prepare
>> + */
>> +void Awb::prepare(IPAContext &context,
>> + rkisp1_params_cfg *params)
>
> This holds on a single line.
>
>> +{
>> + params->others.awb_gain_config.gain_green_b = 256 * context.frameContext.awb.gains.green;
>> + params->others.awb_gain_config.gain_blue = 256 * context.frameContext.awb.gains.blue;
>> + params->others.awb_gain_config.gain_red = 256 * context.frameContext.awb.gains.red;
>> + params->others.awb_gain_config.gain_green_r = 256 * context.frameContext.awb.gains.green;
>> +
>> + if (context.frameContext.frameId == 0) {
>> + /* Configure the gains to apply. */
>> + params->module_en_update |= RKISP1_CIF_ISP_MODULE_AWB_GAIN;
>> + /* Update the ISP to apply the gains configured. */
>> + params->module_ens |= RKISP1_CIF_ISP_MODULE_AWB_GAIN;
>> + }
>> + /* Update the gains. */
>> + params->module_cfg_update |= RKISP1_CIF_ISP_MODULE_AWB_GAIN;
>
> I'd move this line just after setting the gains above.
>
>> +
>> + /* Configure the measure window for AWB. */
>> + params->meas.awb_meas_config.awb_wnd = context.configuration.awb.measureWindow;
>> + /*
>> + * Measure Y, Cr and Cb means.
>> + * \todo RGB is not working, the kernel seems to not configure it ?
>
> Does this mean that if RGB worked, you would prefer using that ?
Yes, as it would remove the need for the YCrCb to RGB conversion.
>
>> + */
>> + params->meas.awb_meas_config.awb_mode = RKISP1_CIF_ISP_AWB_MODE_YCBCR;
>> + /* Reference Cr and Cb. */
>> + params->meas.awb_meas_config.awb_ref_cb = 128;
>> + params->meas.awb_meas_config.awb_ref_cr = 128;
>> + /* Y values to include are between min_y and max_y only. */
>> + params->meas.awb_meas_config.min_y = 16;
>> + params->meas.awb_meas_config.max_y = 250;
>> + /* Maximum Cr+Cb value to take into account for awb. */
>> + params->meas.awb_meas_config.max_csum = 250;
>> + /* Minimum Cr and Cb values to take into account. */
>> + params->meas.awb_meas_config.min_c = 16;
>> + /* Number of frames to use to estimate the mean (0 means 1 frame). */
>> + params->meas.awb_meas_config.frames = 0;
>
> All this can move inside the if () below.
>
>> +
>> + if (context.frameContext.frameId == 0) {
>> + /* Update AWB measurement unit configuration. */
>> + params->module_cfg_update |= RKISP1_CIF_ISP_MODULE_AWB;
>> + /* Make sure the ISP is measuring the means for the next frame. */
>> + params->module_en_update |= RKISP1_CIF_ISP_MODULE_AWB;
>> + params->module_ens |= RKISP1_CIF_ISP_MODULE_AWB;
>> + }
>> +}
>> +
>> +} /* namespace ipa::rkisp1::algorithms */
>> +
>> +} /* namespace libcamera */
>> diff --git a/src/ipa/rkisp1/algorithms/awb.h b/src/ipa/rkisp1/algorithms/awb.h
>> new file mode 100644
>> index 00000000..0a9fb82c
>> --- /dev/null
>> +++ b/src/ipa/rkisp1/algorithms/awb.h
>> @@ -0,0 +1,33 @@
>> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
>> +/*
>> + * Copyright (C) 2021, Ideas On Board
>
> 2021-2022
>
>> + *
>> + * awb.h - AWB control algorithm
>> + */
>> +
>> +#pragma once
>> +
>> +#include <linux/rkisp1-config.h>
>> +
>> +#include "algorithm.h"
>> +
>> +namespace libcamera {
>> +
>> +namespace ipa::rkisp1::algorithms {
>> +
>> +class Awb : public Algorithm
>> +{
>> +public:
>> + Awb() = default;
>> + ~Awb() = default;
>> +
>> + int configure(IPAContext &context, const IPACameraSensorInfo &configInfo) override;
>> + void prepare(IPAContext &context, rkisp1_params_cfg *params) override;
>> + void process(IPAContext &context, const rkisp1_stat_buffer *stats) override;
>> +
>> +private:
>> + uint32_t estimateCCT(double red, double green, double blue);
>> +};
>> +
>> +} /* namespace ipa::rkisp1::algorithms */
>> +} /* namespace libcamera */
>> diff --git a/src/ipa/rkisp1/algorithms/meson.build b/src/ipa/rkisp1/algorithms/meson.build
>> index 27c97731..7ec53d89 100644
>> --- a/src/ipa/rkisp1/algorithms/meson.build
>> +++ b/src/ipa/rkisp1/algorithms/meson.build
>> @@ -2,5 +2,6 @@
>>
>> rkisp1_ipa_algorithms = files([
>> 'agc.cpp',
>> + 'awb.cpp',
>> 'blc.cpp',
>> ])
>> diff --git a/src/ipa/rkisp1/ipa_context.cpp b/src/ipa/rkisp1/ipa_context.cpp
>> index 39acef47..c25f44ec 100644
>> --- a/src/ipa/rkisp1/ipa_context.cpp
>> +++ b/src/ipa/rkisp1/ipa_context.cpp
>> @@ -81,6 +81,14 @@ namespace libcamera::ipa::rkisp1 {
>> * \brief Hardware revision of the ISP
>> */
>>
>> +/**
>> + * \var IPASessionConfiguration::awb
>> + * \brief AWB parameters configuration of the IPA
>> + *
>> + * \var IPASessionConfiguration::awb.measureWindow
>> + * \brief AWB measure window
>> + */
>> +
>> /**
>> * \var IPASessionConfiguration::sensor
>> * \brief Sensor-specific configuration of the IPA
>> @@ -105,6 +113,26 @@ namespace libcamera::ipa::rkisp1 {
>> * The gain should be adapted to the sensor specific gain code before applying.
>> */
>>
>> +/**
>> + * \var IPAFrameContext::awb
>> + * \brief Context for the Automatic White Balance algorithm
>> + *
>> + * \struct IPAFrameContext::awb.gains
>> + * \brief White balance gains
>> + *
>> + * \var IPAFrameContext::awb.gains.red
>> + * \brief White balance gain for R channel
>> + *
>> + * \var IPAFrameContext::awb.gains.green
>> + * \brief White balance gain for G channel
>> + *
>> + * \var IPAFrameContext::awb.gains.blue
>> + * \brief White balance gain for B channel
>> + *
>> + * \var IPAFrameContext::awb.temperatureK
>> + * \brief Estimated color temperature
>> + */
>> +
>> /**
>> * \var IPAFrameContext::sensor
>> * \brief Effective sensor values
>> diff --git a/src/ipa/rkisp1/ipa_context.h b/src/ipa/rkisp1/ipa_context.h
>> index 9ac3b40c..51eae8b6 100644
>> --- a/src/ipa/rkisp1/ipa_context.h
>> +++ b/src/ipa/rkisp1/ipa_context.h
>> @@ -12,6 +12,8 @@
>>
>> #include <libcamera/base/utils.h>
>>
>> +#include <libcamera/geometry.h>
>> +
>> namespace libcamera {
>>
>> namespace ipa::rkisp1 {
>> @@ -25,6 +27,10 @@ struct IPASessionConfiguration {
>> struct rkisp1_cif_isp_window measureWindow;
>> } agc;
>>
>> + struct {
>> + struct rkisp1_cif_isp_window measureWindow;
>> + } awb;
>> +
>> struct {
>> utils::Duration lineDuration;
>> } sensor;
>> @@ -40,6 +46,16 @@ struct IPAFrameContext {
>> double gain;
>> } agc;
>>
>> + struct {
>> + struct {
>> + double red;
>> + double green;
>> + double blue;
>> + } gains;
>> +
>> + double temperatureK;
>> + } awb;
>> +
>> struct {
>> uint32_t exposure;
>> double gain;
>> diff --git a/src/ipa/rkisp1/rkisp1.cpp b/src/ipa/rkisp1/rkisp1.cpp
>> index f82b7cb3..381fc0e0 100644
>> --- a/src/ipa/rkisp1/rkisp1.cpp
>> +++ b/src/ipa/rkisp1/rkisp1.cpp
>> @@ -27,6 +27,7 @@
>>
>> #include "algorithms/agc.h"
>> #include "algorithms/algorithm.h"
>> +#include "algorithms/awb.h"
>> #include "algorithms/blc.h"
>> #include "libipa/camera_sensor_helper.h"
>>
>> @@ -126,6 +127,7 @@ int IPARkISP1::init(const IPASettings &settings, unsigned int hwRevision)
>>
>> /* Construct our Algorithms */
>> algorithms_.push_back(std::make_unique<algorithms::Agc>());
>> + algorithms_.push_back(std::make_unique<algorithms::Awb>());
>> algorithms_.push_back(std::make_unique<algorithms::BlackLevelCorrection>());
>>
>> return 0;
>
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