[libcamera-devel] [PATCH v1 03/10] ipa: raspberrypi: Generalise the ALSC algorithm

Jacopo Mondi jacopo.mondi at ideasonboard.com
Fri Mar 24 09:30:08 CET 2023


On Wed, Mar 22, 2023 at 01:06:05PM +0000, Naushir Patuck via libcamera-devel wrote:
> Remove any hard-coded assumptions about the target hardware platform
> from the ALSC algorithm. Instead, use the "target" string provided by
> the camera tuning config and generalised statistics structures to
> determing parameters such as grid and region sizes.
>
> The ALSC calculations use run-time allocated arrays/vectors on every
> frame. Allocating these might add a non-trivial run-time penalty.
> Replace these dynamic allocations with a set of reusable pre-allocated
> vectors during the init phase.
>
> Signed-off-by: Naushir Patuck <naush at raspberrypi.com>
> Signed-off-by: David Plowman <david.plowman at raspberrypi.com>
> ---
>  src/ipa/raspberrypi/controller/alsc_status.h |  13 +-
>  src/ipa/raspberrypi/controller/rpi/alsc.cpp  | 341 +++++++++++--------
>  src/ipa/raspberrypi/controller/rpi/alsc.h    |  29 +-
>  src/ipa/raspberrypi/raspberrypi.cpp          |   9 +-
>  4 files changed, 224 insertions(+), 168 deletions(-)
>
> diff --git a/src/ipa/raspberrypi/controller/alsc_status.h b/src/ipa/raspberrypi/controller/alsc_status.h
> index e5aa7e37c330..49a9f4a0cb5a 100644
> --- a/src/ipa/raspberrypi/controller/alsc_status.h
> +++ b/src/ipa/raspberrypi/controller/alsc_status.h
> @@ -6,16 +6,17 @@
>   */
>  #pragma once
>
> +#include <vector>
> +
>  /*
>   * The ALSC algorithm should post the following structure into the image's
>   * "alsc.status" metadata.
>   */
>
> -constexpr unsigned int AlscCellsX = 16;
> -constexpr unsigned int AlscCellsY = 12;
> -
>  struct AlscStatus {
> -	double r[AlscCellsY][AlscCellsX];
> -	double g[AlscCellsY][AlscCellsX];
> -	double b[AlscCellsY][AlscCellsX];
> +	std::vector<double> r;
> +	std::vector<double> g;
> +	std::vector<double> b;
> +	unsigned int rows;
> +	unsigned int cols;
>  };
> diff --git a/src/ipa/raspberrypi/controller/rpi/alsc.cpp b/src/ipa/raspberrypi/controller/rpi/alsc.cpp
> index eb4e2f9496e1..51fe5d73f52d 100644
> --- a/src/ipa/raspberrypi/controller/rpi/alsc.cpp
> +++ b/src/ipa/raspberrypi/controller/rpi/alsc.cpp
> @@ -5,6 +5,7 @@
>   * alsc.cpp - ALSC (auto lens shading correction) control algorithm
>   */
>
> +#include <algorithm>
>  #include <functional>
>  #include <math.h>
>  #include <numeric>
> @@ -24,9 +25,6 @@ LOG_DEFINE_CATEGORY(RPiAlsc)
>
>  #define NAME "rpi.alsc"
>
> -static const int X = AlscCellsX;
> -static const int Y = AlscCellsY;
> -static const int XY = X * Y;
>  static const double InsufficientData = -1.0;
>
>  Alsc::Alsc(Controller *controller)
> @@ -51,8 +49,11 @@ char const *Alsc::name() const
>  	return NAME;
>  }
>
> -static int generateLut(double *lut, const libcamera::YamlObject &params)
> +static int generateLut(std::vector<double> &lut, const libcamera::YamlObject &params,
> +		       const Size &size)
>  {
> +	/* These must be signed ints for the co-ordinate calculations below. */
> +	int X = size.width, Y = size.height;
>  	double cstrength = params["corner_strength"].get<double>(2.0);
>  	if (cstrength <= 1.0) {
>  		LOG(RPiAlsc, Error) << "corner_strength must be > 1.0";
> @@ -81,9 +82,9 @@ static int generateLut(double *lut, const libcamera::YamlObject &params)
>  	return 0;
>  }
>
> -static int readLut(double *lut, const libcamera::YamlObject &params)
> +static int readLut(std::vector<double> &lut, const libcamera::YamlObject &params, const Size &size)
>  {
> -	if (params.size() != XY) {
> +	if (params.size() != size.width * size.height) {
>  		LOG(RPiAlsc, Error) << "Invalid number of entries in LSC table";
>  		return -EINVAL;
>  	}
> @@ -101,7 +102,7 @@ static int readLut(double *lut, const libcamera::YamlObject &params)
>
>  static int readCalibrations(std::vector<AlscCalibration> &calibrations,
>  			    const libcamera::YamlObject &params,
> -			    std::string const &name)
> +			    std::string const &name, const Size &size)
>  {
>  	if (params.contains(name)) {
>  		double lastCt = 0;
> @@ -119,7 +120,7 @@ static int readCalibrations(std::vector<AlscCalibration> &calibrations,
>  			calibration.ct = lastCt = ct;
>
>  			const libcamera::YamlObject &table = p["table"];
> -			if (table.size() != XY) {
> +			if (table.size() != size.width * size.height) {
>  				LOG(RPiAlsc, Error)
>  					<< "Incorrect number of values for ct "
>  					<< ct << " in " << name;
> @@ -127,6 +128,7 @@ static int readCalibrations(std::vector<AlscCalibration> &calibrations,
>  			}
>
>  			int num = 0;
> +			calibration.table.resize(size.width * size.height);
>  			for (const auto &elem : table.asList()) {
>  				value = elem.get<double>();
>  				if (!value)
> @@ -134,7 +136,7 @@ static int readCalibrations(std::vector<AlscCalibration> &calibrations,
>  				calibration.table[num++] = *value;
>  			}
>
> -			calibrations.push_back(calibration);
> +			calibrations.push_back(std::move(calibration));
>  			LOG(RPiAlsc, Debug)
>  				<< "Read " << name << " calibration for ct " << ct;
>  		}
> @@ -144,6 +146,7 @@ static int readCalibrations(std::vector<AlscCalibration> &calibrations,
>
>  int Alsc::read(const libcamera::YamlObject &params)
>  {
> +	config_.tableSize = getHardwareConfig().awbRegions;
>  	config_.framePeriod = params["frame_period"].get<uint16_t>(12);
>  	config_.startupFrames = params["startup_frames"].get<uint16_t>(10);
>  	config_.speed = params["speed"].get<double>(0.05);
> @@ -153,28 +156,29 @@ int Alsc::read(const libcamera::YamlObject &params)
>  	config_.minCount = params["min_count"].get<double>(10.0);
>  	config_.minG = params["min_G"].get<uint16_t>(50);
>  	config_.omega = params["omega"].get<double>(1.3);
> -	config_.nIter = params["n_iter"].get<uint32_t>(X + Y);
> +	config_.nIter = params["n_iter"].get<uint32_t>(config_.tableSize.width + config_.tableSize.height);
>  	config_.luminanceStrength =
>  		params["luminance_strength"].get<double>(1.0);
> -	for (int i = 0; i < XY; i++)
> -		config_.luminanceLut[i] = 1.0;
>
> +	config_.luminanceLut.resize(config_.tableSize.width * config_.tableSize.height, 1.0);
>  	int ret = 0;
>
>  	if (params.contains("corner_strength"))
> -		ret = generateLut(config_.luminanceLut, params);
> +		ret = generateLut(config_.luminanceLut, params, config_.tableSize);
>  	else if (params.contains("luminance_lut"))
> -		ret = readLut(config_.luminanceLut, params["luminance_lut"]);
> +		ret = readLut(config_.luminanceLut, params["luminance_lut"], config_.tableSize);
>  	else
>  		LOG(RPiAlsc, Warning)
>  			<< "no luminance table - assume unity everywhere";
>  	if (ret)
>  		return ret;
>
> -	ret = readCalibrations(config_.calibrationsCr, params, "calibrations_Cr");
> +	ret = readCalibrations(config_.calibrationsCr, params, "calibrations_Cr",
> +			       config_.tableSize);
>  	if (ret)
>  		return ret;
> -	ret = readCalibrations(config_.calibrationsCb, params, "calibrations_Cb");
> +	ret = readCalibrations(config_.calibrationsCb, params, "calibrations_Cb",
> +			       config_.tableSize);
>  	if (ret)
>  		return ret;
>
> @@ -187,13 +191,16 @@ int Alsc::read(const libcamera::YamlObject &params)
>
>  static double getCt(Metadata *metadata, double defaultCt);
>  static void getCalTable(double ct, std::vector<AlscCalibration> const &calibrations,
> -			double calTable[XY]);
> -static void resampleCalTable(double const calTableIn[XY], CameraMode const &cameraMode,
> -			     double calTableOut[XY]);
> -static void compensateLambdasForCal(double const calTable[XY], double const oldLambdas[XY],
> -				    double newLambdas[XY]);
> -static void addLuminanceToTables(double results[3][Y][X], double const lambdaR[XY], double lambdaG,
> -				 double const lambdaB[XY], double const luminanceLut[XY],
> +			std::vector<double> &calTable);
> +static void resampleCalTable(const std::vector<double> &calTableIn, CameraMode const &cameraMode,
> +			     const Size &size, std::vector<double> &calTableOut);
> +static void compensateLambdasForCal(const std::vector<double> &calTable,
> +				    const std::vector<double> &oldLambdas,
> +				    std::vector<double> &newLambdas);
> +static void addLuminanceToTables(std::array<std::vector<double>, 3> &results,
> +				 const std::vector<double> &lambdaR, double lambdaG,
> +				 const std::vector<double> &lambdaB,
> +				 const std::vector<double> &luminanceLut,
>  				 double luminanceStrength);
>
>  void Alsc::initialise()
> @@ -201,7 +208,28 @@ void Alsc::initialise()
>  	frameCount2_ = frameCount_ = framePhase_ = 0;
>  	firstTime_ = true;
>  	ct_ = config_.defaultCt;
> +
> +	const size_t XY = config_.tableSize.width * config_.tableSize.height;
> +
> +	for (auto &r : syncResults_)
> +		r.resize(XY);
> +	for (auto &r : prevSyncResults_)
> +		r.resize(XY);
> +	for (auto &r : asyncResults_)
> +		r.resize(XY);
> +
> +	luminanceTable_.resize(XY);
> +	asyncLambdaR_.resize(XY);
> +	asyncLambdaB_.resize(XY);
>  	/* The lambdas are initialised in the SwitchMode. */
> +	lambdaR_.resize(XY);
> +	lambdaB_.resize(XY);
> +
> +	/* Temporaries for the computations, but sensible to allocate this up-front! */
> +	for (auto &c : tmpC_)
> +		c.resize(XY);
> +	for (auto &m : tmpM_)
> +		m.resize(XY);
>  }
>
>  void Alsc::waitForAysncThread()
> @@ -262,7 +290,7 @@ void Alsc::switchMode(CameraMode const &cameraMode,
>  	 * We must resample the luminance table like we do the others, but it's
>  	 * fixed so we can simply do it up front here.
>  	 */
> -	resampleCalTable(config_.luminanceLut, cameraMode_, luminanceTable_);
> +	resampleCalTable(config_.luminanceLut, cameraMode_, config_.tableSize, luminanceTable_);
>
>  	if (resetTables) {
>  		/*
> @@ -272,18 +300,18 @@ void Alsc::switchMode(CameraMode const &cameraMode,
>  		 * the lambdas, but the rest of this code then echoes the code in
>  		 * doAlsc, without the adaptive algorithm.
>  		 */
> -		for (int i = 0; i < XY; i++)
> -			lambdaR_[i] = lambdaB_[i] = 1.0;
> -		double calTableR[XY], calTableB[XY], calTableTmp[XY];
> +		std::fill(lambdaR_.begin(), lambdaR_.end(), 1.0);
> +		std::fill(lambdaB_.begin(), lambdaB_.end(), 1.0);
> +		std::vector<double> &calTableR = tmpC_[0], &calTableB = tmpC_[1], &calTableTmp = tmpC_[2];
>  		getCalTable(ct_, config_.calibrationsCr, calTableTmp);
> -		resampleCalTable(calTableTmp, cameraMode_, calTableR);
> +		resampleCalTable(calTableTmp, cameraMode_, config_.tableSize, calTableR);
>  		getCalTable(ct_, config_.calibrationsCb, calTableTmp);
> -		resampleCalTable(calTableTmp, cameraMode_, calTableB);
> +		resampleCalTable(calTableTmp, cameraMode_, config_.tableSize, calTableB);
>  		compensateLambdasForCal(calTableR, lambdaR_, asyncLambdaR_);
>  		compensateLambdasForCal(calTableB, lambdaB_, asyncLambdaB_);
>  		addLuminanceToTables(syncResults_, asyncLambdaR_, 1.0, asyncLambdaB_,
>  				     luminanceTable_, config_.luminanceStrength);
> -		memcpy(prevSyncResults_, syncResults_, sizeof(prevSyncResults_));
> +		prevSyncResults_ = syncResults_;
>  		framePhase_ = config_.framePeriod; /* run the algo again asap */
>  		firstTime_ = false;
>  	}
> @@ -294,7 +322,7 @@ void Alsc::fetchAsyncResults()
>  	LOG(RPiAlsc, Debug) << "Fetch ALSC results";
>  	asyncFinished_ = false;
>  	asyncStarted_ = false;
> -	memcpy(syncResults_, asyncResults_, sizeof(syncResults_));
> +	syncResults_ = asyncResults_;
>  }
>
>  double getCt(Metadata *metadata, double defaultCt)
> @@ -316,9 +344,9 @@ static void copyStats(RgbyRegions &regions, StatisticsPtr &stats,
>  	if (!regions.numRegions())
>  		regions.init(stats->awbRegions.size());
>
> -	double *rTable = (double *)status.r;
> -	double *gTable = (double *)status.g;
> -	double *bTable = (double *)status.b;
> +	const std::vector<double> &rTable = status.r;
> +	const std::vector<double> &gTable = status.g;
> +	const std::vector<double> &bTable = status.b;
>  	for (unsigned int i = 0; i < stats->awbRegions.numRegions(); i++) {
>  		auto r = stats->awbRegions.get(i);
>  		r.val.rSum = static_cast<uint64_t>(r.val.rSum / rTable[i]);
> @@ -344,12 +372,9 @@ void Alsc::restartAsync(StatisticsPtr &stats, Metadata *imageMetadata)
>  	if (imageMetadata->get("alsc.status", alscStatus) != 0) {
>  		LOG(RPiAlsc, Warning)
>  			<< "No ALSC status found for applied gains!";
> -		for (int y = 0; y < Y; y++)
> -			for (int x = 0; x < X; x++) {
> -				alscStatus.r[y][x] = 1.0;
> -				alscStatus.g[y][x] = 1.0;
> -				alscStatus.b[y][x] = 1.0;
> -			}
> +		alscStatus.r.resize(config_.tableSize.width * config_.tableSize.height, 1.0);
> +		alscStatus.g.resize(config_.tableSize.width * config_.tableSize.height, 1.0);
> +		alscStatus.b.resize(config_.tableSize.width * config_.tableSize.height, 1.0);
>  	}
>  	copyStats(statistics_, stats, alscStatus);
>  	framePhase_ = 0;
> @@ -380,15 +405,15 @@ void Alsc::prepare(Metadata *imageMetadata)
>  			fetchAsyncResults();
>  	}
>  	/* Apply IIR filter to results and program into the pipeline. */
> -	double *ptr = (double *)syncResults_,
> -	       *pptr = (double *)prevSyncResults_;
> -	for (unsigned int i = 0; i < sizeof(syncResults_) / sizeof(double); i++)
> -		pptr[i] = speed * ptr[i] + (1.0 - speed) * pptr[i];
> +	for (unsigned int j = 0; j < syncResults_.size(); j++) {
> +		for (unsigned int i = 0; i < syncResults_[j].size(); i++)
> +			prevSyncResults_[j][i] = speed * syncResults_[j][i] + (1.0 - speed) * prevSyncResults_[j][i];
> +	}
>  	/* Put output values into status metadata. */
>  	AlscStatus status;
> -	memcpy(status.r, prevSyncResults_[0], sizeof(status.r));
> -	memcpy(status.g, prevSyncResults_[1], sizeof(status.g));
> -	memcpy(status.b, prevSyncResults_[2], sizeof(status.b));
> +	status.r = prevSyncResults_[0];
> +	status.g = prevSyncResults_[1];
> +	status.b = prevSyncResults_[2];
>  	imageMetadata->set("alsc.status", status);
>  }
>
> @@ -432,18 +457,17 @@ void Alsc::asyncFunc()
>  }
>
>  void getCalTable(double ct, std::vector<AlscCalibration> const &calibrations,
> -		 double calTable[XY])
> +		 std::vector<double> &calTable)
>  {
>  	if (calibrations.empty()) {
> -		for (int i = 0; i < XY; i++)
> -			calTable[i] = 1.0;
> +		std::fill(calTable.begin(), calTable.end(), 1.0);
>  		LOG(RPiAlsc, Debug) << "no calibrations found";
>  	} else if (ct <= calibrations.front().ct) {
> -		memcpy(calTable, calibrations.front().table, XY * sizeof(double));
> +		calTable = calibrations.front().table;
>  		LOG(RPiAlsc, Debug) << "using calibration for "
>  				    << calibrations.front().ct;
>  	} else if (ct >= calibrations.back().ct) {
> -		memcpy(calTable, calibrations.back().table, XY * sizeof(double));
> +		calTable = calibrations.back().table;
>  		LOG(RPiAlsc, Debug) << "using calibration for "
>  				    << calibrations.back().ct;
>  	} else {
> @@ -454,7 +478,7 @@ void getCalTable(double ct, std::vector<AlscCalibration> const &calibrations,
>  		LOG(RPiAlsc, Debug)
>  			<< "ct is " << ct << ", interpolating between "
>  			<< ct0 << " and " << ct1;
> -		for (int i = 0; i < XY; i++)
> +		for (unsigned int i = 0; i < calTable.size(); i++)
>  			calTable[i] =
>  				(calibrations[idx].table[i] * (ct1 - ct) +
>  				 calibrations[idx + 1].table[i] * (ct - ct0)) /
> @@ -462,9 +486,13 @@ void getCalTable(double ct, std::vector<AlscCalibration> const &calibrations,
>  	}
>  }
>
> -void resampleCalTable(double const calTableIn[XY],
> -		      CameraMode const &cameraMode, double calTableOut[XY])
> +void resampleCalTable(const std::vector<double> &calTableIn,
> +		      CameraMode const &cameraMode, const Size &size,
> +		      std::vector<double> &calTableOut)
>  {
> +	int X = size.width;
> +	int Y = size.height;
> +
>  	/*
>  	 * Precalculate and cache the x sampling locations and phases to save
>  	 * recomputing them on every row.
> @@ -501,23 +529,24 @@ void resampleCalTable(double const calTableIn[XY],
>  			yLo = Y - 1 - yLo;
>  			yHi = Y - 1 - yHi;
>  		}
> -		double const *rowAbove = calTableIn + X * yLo;
> -		double const *rowBelow = calTableIn + X * yHi;
> +		double const *rowAbove = calTableIn.data() + X * yLo;
> +		double const *rowBelow = calTableIn.data() + X * yHi;
> +		double *out = calTableOut.data() + X * j;
>  		for (int i = 0; i < X; i++) {
>  			double above = rowAbove[xLo[i]] * (1 - xf[i]) +
>  				       rowAbove[xHi[i]] * xf[i];
>  			double below = rowBelow[xLo[i]] * (1 - xf[i]) +
>  				       rowBelow[xHi[i]] * xf[i];
> -			*(calTableOut++) = above * (1 - yf) + below * yf;
> +			*(out++) = above * (1 - yf) + below * yf;
>  		}
>  	}
>  }
>
>  /* Calculate chrominance statistics (R/G and B/G) for each region. */
> -static void calculateCrCb(const RgbyRegions &awbRegion, double cr[XY],
> -			  double cb[XY], uint32_t minCount, uint16_t minG)
> +static void calculateCrCb(const RgbyRegions &awbRegion, std::vector<double> &cr,
> +			  std::vector<double> &cb, uint32_t minCount, uint16_t minG)
>  {
> -	for (int i = 0; i < XY; i++) {
> +	for (unsigned int i = 0; i < cr.size(); i++) {
>  		auto s = awbRegion.get(i);
>
>  		if (s.counted <= minCount || s.val.gSum / s.counted <= minG) {
> @@ -530,33 +559,34 @@ static void calculateCrCb(const RgbyRegions &awbRegion, double cr[XY],
>  	}
>  }
>
> -static void applyCalTable(double const calTable[XY], double C[XY])
> +static void applyCalTable(const std::vector<double> &calTable, std::vector<double> &C)
>  {
> -	for (int i = 0; i < XY; i++)
> +	for (unsigned int i = 0; i < C.size(); i++)
>  		if (C[i] != InsufficientData)
>  			C[i] *= calTable[i];
>  }
>
> -void compensateLambdasForCal(double const calTable[XY],
> -			     double const oldLambdas[XY],
> -			     double newLambdas[XY])
> +void compensateLambdasForCal(const std::vector<double> &calTable,
> +			     const std::vector<double> &oldLambdas,
> +			     std::vector<double> &newLambdas)
>  {
>  	double minNewLambda = std::numeric_limits<double>::max();
> -	for (int i = 0; i < XY; i++) {
> +	for (unsigned int i = 0; i < newLambdas.size(); i++) {
>  		newLambdas[i] = oldLambdas[i] * calTable[i];
>  		minNewLambda = std::min(minNewLambda, newLambdas[i]);
>  	}
> -	for (int i = 0; i < XY; i++)
> +	for (unsigned int i = 0; i < newLambdas.size(); i++)
>  		newLambdas[i] /= minNewLambda;
>  }
>
> -[[maybe_unused]] static void printCalTable(double const C[XY])
> +[[maybe_unused]] static void printCalTable(const std::vector<double> &C,
> +					   const Size &size)
>  {
>  	printf("table: [\n");
> -	for (int j = 0; j < Y; j++) {
> -		for (int i = 0; i < X; i++) {
> -			printf("%5.3f", 1.0 / C[j * X + i]);
> -			if (i != X - 1 || j != Y - 1)
> +	for (unsigned int j = 0; j < size.height; j++) {
> +		for (unsigned int i = 0; i < size.width; i++) {
> +			printf("%5.3f", 1.0 / C[j * size.width + i]);
> +			if (i != size.width - 1 || j != size.height - 1)
>  				printf(",");
>  		}
>  		printf("\n");
> @@ -577,9 +607,13 @@ static double computeWeight(double Ci, double Cj, double sigma)
>  }
>
>  /* Compute all weights. */
> -static void computeW(double const C[XY], double sigma, double W[XY][4])
> +static void computeW(const std::vector<double> &C, double sigma,
> +		     std::vector<std::array<double, 4>> &W, const Size &size)
>  {
> -	for (int i = 0; i < XY; i++) {
> +	size_t XY = size.width * size.height;
> +	size_t X = size.width;
> +
> +	for (unsigned int i = 0; i < XY; i++) {
>  		/* Start with neighbour above and go clockwise. */
>  		W[i][0] = i >= X ? computeWeight(C[i], C[i - X], sigma) : 0;
>  		W[i][1] = i % X < X - 1 ? computeWeight(C[i], C[i + 1], sigma) : 0;
> @@ -589,11 +623,16 @@ static void computeW(double const C[XY], double sigma, double W[XY][4])
>  }
>
>  /* Compute M, the large but sparse matrix such that M * lambdas = 0. */
> -static void constructM(double const C[XY], double const W[XY][4],
> -		       double M[XY][4])
> +static void constructM(const std::vector<double> &C,
> +		       const std::vector<std::array<double, 4>> &W,
> +		       std::vector<std::array<double, 4>> &M,
> +		       const Size &size)
>  {
> +	size_t XY = size.width * size.height;
> +	size_t X = size.width;
> +
>  	double epsilon = 0.001;
> -	for (int i = 0; i < XY; i++) {
> +	for (unsigned int i = 0; i < XY; i++) {
>  		/*
>  		 * Note how, if C[i] == INSUFFICIENT_DATA, the weights will all
>  		 * be zero so the equation is still set up correctly.
> @@ -614,79 +653,80 @@ static void constructM(double const C[XY], double const W[XY][4],
>   * left/right neighbours are zero down the left/right edges, so we don't need
>   * need to test the i value to exclude them.
>   */
> -static double computeLambdaBottom(int i, double const M[XY][4],
> -				  double lambda[XY])
> +static double computeLambdaBottom(int i, const std::vector<std::array<double, 4>> &M,
> +				  std::vector<double> &lambda, const Size &size)
>  {
> -	return M[i][1] * lambda[i + 1] + M[i][2] * lambda[i + X] +
> +	return M[i][1] * lambda[i + 1] + M[i][2] * lambda[i + size.width] +
>  	       M[i][3] * lambda[i - 1];
>  }
> -static double computeLambdaBottomStart(int i, double const M[XY][4],
> -				       double lambda[XY])
> +static double computeLambdaBottomStart(int i, const std::vector<std::array<double, 4>> &M,
> +				       std::vector<double> &lambda, const Size &size)
>  {
> -	return M[i][1] * lambda[i + 1] + M[i][2] * lambda[i + X];
> +	return M[i][1] * lambda[i + 1] + M[i][2] * lambda[i + size.width];
>  }
> -static double computeLambdaInterior(int i, double const M[XY][4],
> -				    double lambda[XY])
> +static double computeLambdaInterior(int i, const std::vector<std::array<double, 4>> &M,
> +				    std::vector<double> &lambda, const Size &size)
>  {
> -	return M[i][0] * lambda[i - X] + M[i][1] * lambda[i + 1] +
> -	       M[i][2] * lambda[i + X] + M[i][3] * lambda[i - 1];
> +	return M[i][0] * lambda[i - size.width] + M[i][1] * lambda[i + 1] +
> +	       M[i][2] * lambda[i + size.width] + M[i][3] * lambda[i - 1];
>  }
> -static double computeLambdaTop(int i, double const M[XY][4],
> -			       double lambda[XY])
> +static double computeLambdaTop(int i, const std::vector<std::array<double, 4>> &M,
> +			       std::vector<double> &lambda, const Size &size)
>  {
> -	return M[i][0] * lambda[i - X] + M[i][1] * lambda[i + 1] +
> +	return M[i][0] * lambda[i - size.width] + M[i][1] * lambda[i + 1] +
>  	       M[i][3] * lambda[i - 1];
>  }
> -static double computeLambdaTopEnd(int i, double const M[XY][4],
> -				  double lambda[XY])
> +static double computeLambdaTopEnd(int i, const std::vector<std::array<double, 4>> &M,
> +				  std::vector<double> &lambda, const Size &size)
>  {
> -	return M[i][0] * lambda[i - X] + M[i][3] * lambda[i - 1];
> +	return M[i][0] * lambda[i - size.width] + M[i][3] * lambda[i - 1];
>  }
>
>  /* Gauss-Seidel iteration with over-relaxation. */
> -static double gaussSeidel2Sor(double const M[XY][4], double omega,
> -			      double lambda[XY], double lambdaBound)
> +static double gaussSeidel2Sor(const std::vector<std::array<double, 4>> &M, double omega,
> +			      std::vector<double> &lambda, double lambdaBound,
> +			      const Size &size)
>  {
> +	int XY = size.width * size.height;
> +	int X = size.width;
>  	const double min = 1 - lambdaBound, max = 1 + lambdaBound;
> -	double oldLambda[XY];
> +	std::vector<double> oldLambda = lambda;
>  	int i;
> -	for (i = 0; i < XY; i++)
> -		oldLambda[i] = lambda[i];
> -	lambda[0] = computeLambdaBottomStart(0, M, lambda);
> +	lambda[0] = computeLambdaBottomStart(0, M, lambda, size);
>  	lambda[0] = std::clamp(lambda[0], min, max);
>  	for (i = 1; i < X; i++) {
> -		lambda[i] = computeLambdaBottom(i, M, lambda);
> +		lambda[i] = computeLambdaBottom(i, M, lambda, size);
>  		lambda[i] = std::clamp(lambda[i], min, max);
>  	}
>  	for (; i < XY - X; i++) {
> -		lambda[i] = computeLambdaInterior(i, M, lambda);
> +		lambda[i] = computeLambdaInterior(i, M, lambda, size);
>  		lambda[i] = std::clamp(lambda[i], min, max);
>  	}
>  	for (; i < XY - 1; i++) {
> -		lambda[i] = computeLambdaTop(i, M, lambda);
> +		lambda[i] = computeLambdaTop(i, M, lambda, size);
>  		lambda[i] = std::clamp(lambda[i], min, max);
>  	}
> -	lambda[i] = computeLambdaTopEnd(i, M, lambda);
> +	lambda[i] = computeLambdaTopEnd(i, M, lambda, size);
>  	lambda[i] = std::clamp(lambda[i], min, max);
>  	/*
>  	 * Also solve the system from bottom to top, to help spread the updates
>  	 * better.
>  	 */
> -	lambda[i] = computeLambdaTopEnd(i, M, lambda);
> +	lambda[i] = computeLambdaTopEnd(i, M, lambda, size);
>  	lambda[i] = std::clamp(lambda[i], min, max);
>  	for (i = XY - 2; i >= XY - X; i--) {
> -		lambda[i] = computeLambdaTop(i, M, lambda);
> +		lambda[i] = computeLambdaTop(i, M, lambda, size);
>  		lambda[i] = std::clamp(lambda[i], min, max);
>  	}
>  	for (; i >= X; i--) {
> -		lambda[i] = computeLambdaInterior(i, M, lambda);
> +		lambda[i] = computeLambdaInterior(i, M, lambda, size);
>  		lambda[i] = std::clamp(lambda[i], min, max);
>  	}
>  	for (; i >= 1; i--) {
> -		lambda[i] = computeLambdaBottom(i, M, lambda);
> +		lambda[i] = computeLambdaBottom(i, M, lambda, size);
>  		lambda[i] = std::clamp(lambda[i], min, max);
>  	}
> -	lambda[0] = computeLambdaBottomStart(0, M, lambda);
> +	lambda[0] = computeLambdaBottomStart(0, M, lambda, size);
>  	lambda[0] = std::clamp(lambda[0], min, max);
>  	double maxDiff = 0;
>  	for (i = 0; i < XY; i++) {
> @@ -698,33 +738,33 @@ static double gaussSeidel2Sor(double const M[XY][4], double omega,
>  }
>
>  /* Normalise the values so that the smallest value is 1. */
> -static void normalise(double *ptr, size_t n)
> +static void normalise(std::vector<double> &results)
>  {
> -	double minval = ptr[0];
> -	for (size_t i = 1; i < n; i++)
> -		minval = std::min(minval, ptr[i]);
> -	for (size_t i = 0; i < n; i++)
> -		ptr[i] /= minval;
> +	double minval = *std::min_element(results.begin(), results.end());
> +	std::for_each(results.begin(), results.end(),
> +		      [minval](double val) { return val / minval; });
>  }
>
>  /* Rescale the values so that the average value is 1. */
> -static void reaverage(Span<double> data)
> +static void reaverage(std::vector<double> &data)
>  {
>  	double sum = std::accumulate(data.begin(), data.end(), 0.0);
>  	double ratio = 1 / (sum / data.size());
> -	for (double &d : data)
> -		d *= ratio;
> +	std::for_each(data.begin(), data.end(),
> +		      [ratio](double val) { return val * ratio; });
>  }
>
> -static void runMatrixIterations(double const C[XY], double lambda[XY],
> -				double const W[XY][4], double omega,
> -				int nIter, double threshold, double lambdaBound)
> +static void runMatrixIterations(const std::vector<double> &C,
> +				std::vector<double> &lambda,
> +				const std::vector<std::array<double, 4>> &W,
> +				std::vector<std::array<double, 4>> &M, double omega,
> +				unsigned int nIter, double threshold, double lambdaBound,
> +				const Size &size)
>  {
> -	double M[XY][4];
> -	constructM(C, W, M);
> +	constructM(C, W, M, size);
>  	double lastMaxDiff = std::numeric_limits<double>::max();
> -	for (int i = 0; i < nIter; i++) {
> -		double maxDiff = fabs(gaussSeidel2Sor(M, omega, lambda, lambdaBound));
> +	for (unsigned int i = 0; i < nIter; i++) {
> +		double maxDiff = fabs(gaussSeidel2Sor(M, omega, lambda, lambdaBound, size));
>  		if (maxDiff < threshold) {
>  			LOG(RPiAlsc, Debug)
>  				<< "Stop after " << i + 1 << " iterations";
> @@ -741,39 +781,44 @@ static void runMatrixIterations(double const C[XY], double lambda[XY],
>  		lastMaxDiff = maxDiff;
>  	}
>  	/* We're going to normalise the lambdas so the total average is 1. */
> -	reaverage({ lambda, XY });
> +	reaverage(lambda);
>  }
>
> -static void addLuminanceRb(double result[XY], double const lambda[XY],
> -			   double const luminanceLut[XY],
> +static void addLuminanceRb(std::vector<double> &result, const std::vector<double> &lambda,
> +			   const std::vector<double> &luminanceLut,
>  			   double luminanceStrength)
>  {
> -	for (int i = 0; i < XY; i++)
> +	for (unsigned int i = 0; i < result.size(); i++)
>  		result[i] = lambda[i] * ((luminanceLut[i] - 1) * luminanceStrength + 1);
>  }
>
> -static void addLuminanceG(double result[XY], double lambda,
> -			  double const luminanceLut[XY],
> +static void addLuminanceG(std::vector<double> &result, double lambda,
> +			  const std::vector<double> &luminanceLut,
>  			  double luminanceStrength)
>  {
> -	for (int i = 0; i < XY; i++)
> +	for (unsigned int i = 0; i < result.size(); i++)
>  		result[i] = lambda * ((luminanceLut[i] - 1) * luminanceStrength + 1);
>  }
>
> -void addLuminanceToTables(double results[3][Y][X], double const lambdaR[XY],
> -			  double lambdaG, double const lambdaB[XY],
> -			  double const luminanceLut[XY],
> +void addLuminanceToTables(std::array<std::vector<double>, 3> &results,
> +			  const std::vector<double> &lambdaR,
> +			  double lambdaG, const std::vector<double> &lambdaB,
> +			  const std::vector<double> &luminanceLut,
>  			  double luminanceStrength)
>  {
> -	addLuminanceRb((double *)results[0], lambdaR, luminanceLut, luminanceStrength);
> -	addLuminanceG((double *)results[1], lambdaG, luminanceLut, luminanceStrength);
> -	addLuminanceRb((double *)results[2], lambdaB, luminanceLut, luminanceStrength);
> -	normalise((double *)results, 3 * XY);
> +	addLuminanceRb(results[0], lambdaR, luminanceLut, luminanceStrength);
> +	addLuminanceG(results[1], lambdaG, luminanceLut, luminanceStrength);
> +	addLuminanceRb(results[2], lambdaB, luminanceLut, luminanceStrength);
> +	for (auto &r : results)
> +		normalise(r);
>  }
>
>  void Alsc::doAlsc()
>  {
> -	double cr[XY], cb[XY], wr[XY][4], wb[XY][4], calTableR[XY], calTableB[XY], calTableTmp[XY];
> +	std::vector<double> &cr = tmpC_[0], &cb = tmpC_[1], &calTableR = tmpC_[2],
> +			    &calTableB = tmpC_[3], &calTableTmp = tmpC_[4];
> +	std::vector<std::array<double, 4>> &wr = tmpM_[0], &wb = tmpM_[1], &M = tmpM_[2];
> +
>  	/*
>  	 * Calculate our R/B ("Cr"/"Cb") colour statistics, and assess which are
>  	 * usable.
> @@ -784,9 +829,9 @@ void Alsc::doAlsc()
>  	 * case the camera mode is not full-frame.
>  	 */
>  	getCalTable(ct_, config_.calibrationsCr, calTableTmp);
> -	resampleCalTable(calTableTmp, cameraMode_, calTableR);
> +	resampleCalTable(calTableTmp, cameraMode_, config_.tableSize, calTableR);
>  	getCalTable(ct_, config_.calibrationsCb, calTableTmp);
> -	resampleCalTable(calTableTmp, cameraMode_, calTableB);
> +	resampleCalTable(calTableTmp, cameraMode_, config_.tableSize, calTableB);
>  	/*
>  	 * You could print out the cal tables for this image here, if you're
>  	 * tuning the algorithm...
> @@ -796,13 +841,13 @@ void Alsc::doAlsc()
>  	applyCalTable(calTableR, cr);
>  	applyCalTable(calTableB, cb);
>  	/* Compute weights between zones. */
> -	computeW(cr, config_.sigmaCr, wr);
> -	computeW(cb, config_.sigmaCb, wb);
> +	computeW(cr, config_.sigmaCr, wr, config_.tableSize);
> +	computeW(cb, config_.sigmaCb, wb, config_.tableSize);
>  	/* Run Gauss-Seidel iterations over the resulting matrix, for R and B. */
> -	runMatrixIterations(cr, lambdaR_, wr, config_.omega, config_.nIter,
> -			    config_.threshold, config_.lambdaBound);
> -	runMatrixIterations(cb, lambdaB_, wb, config_.omega, config_.nIter,
> -			    config_.threshold, config_.lambdaBound);
> +	runMatrixIterations(cr, lambdaR_, wr, M, config_.omega, config_.nIter,
> +			    config_.threshold, config_.lambdaBound, config_.tableSize);
> +	runMatrixIterations(cb, lambdaB_, wb, M, config_.omega, config_.nIter,
> +			    config_.threshold, config_.lambdaBound, config_.tableSize);
>  	/*
>  	 * Fold the calibrated gains into our final lambda values. (Note that on
>  	 * the next run, we re-start with the lambda values that don't have the
> diff --git a/src/ipa/raspberrypi/controller/rpi/alsc.h b/src/ipa/raspberrypi/controller/rpi/alsc.h
> index 9167c9ffa2e3..85e998db40e9 100644
> --- a/src/ipa/raspberrypi/controller/rpi/alsc.h
> +++ b/src/ipa/raspberrypi/controller/rpi/alsc.h
> @@ -6,9 +6,13 @@
>   */
>  #pragma once
>
> +#include <array>
>  #include <mutex>
>  #include <condition_variable>
>  #include <thread>
> +#include <vector>
> +
> +#include <libcamera/geometry.h>
>
>  #include "../algorithm.h"
>  #include "../alsc_status.h"
> @@ -20,7 +24,7 @@ namespace RPiController {
>
>  struct AlscCalibration {
>  	double ct;
> -	double table[AlscCellsX * AlscCellsY];
> +	std::vector<double> table;
>  };
>
>  struct AlscConfig {
> @@ -36,13 +40,14 @@ struct AlscConfig {
>  	uint16_t minG;
>  	double omega;
>  	uint32_t nIter;
> -	double luminanceLut[AlscCellsX * AlscCellsY];
> +	std::vector<double> luminanceLut;
>  	double luminanceStrength;
>  	std::vector<AlscCalibration> calibrationsCr;
>  	std::vector<AlscCalibration> calibrationsCb;
>  	double defaultCt; /* colour temperature if no metadata found */
>  	double threshold; /* iteration termination threshold */
>  	double lambdaBound; /* upper/lower bound for lambda from a value of 1 */
> +	libcamera::Size tableSize;
>  };
>
>  class Alsc : public Algorithm
> @@ -62,7 +67,7 @@ private:
>  	AlscConfig config_;
>  	bool firstTime_;
>  	CameraMode cameraMode_;
> -	double luminanceTable_[AlscCellsX * AlscCellsY];
> +	std::vector<double> luminanceTable_;
>  	std::thread asyncThread_;
>  	void asyncFunc(); /* asynchronous thread function */
>  	std::mutex mutex_;
> @@ -88,8 +93,8 @@ private:
>  	int frameCount_;
>  	/* counts up to startupFrames for Process function */
>  	int frameCount2_;
> -	double syncResults_[3][AlscCellsY][AlscCellsX];
> -	double prevSyncResults_[3][AlscCellsY][AlscCellsX];
> +	std::array<std::vector<double>, 3> syncResults_;
> +	std::array<std::vector<double>, 3> prevSyncResults_;
>  	void waitForAysncThread();
>  	/*
>  	 * The following are for the asynchronous thread to use, though the main
> @@ -100,12 +105,16 @@ private:
>  	void fetchAsyncResults();
>  	double ct_;
>  	RgbyRegions statistics_;
> -	double asyncResults_[3][AlscCellsY][AlscCellsX];
> -	double asyncLambdaR_[AlscCellsX * AlscCellsY];
> -	double asyncLambdaB_[AlscCellsX * AlscCellsY];
> +	std::array<std::vector<double>, 3> asyncResults_;
> +	std::vector<double> asyncLambdaR_;
> +	std::vector<double> asyncLambdaB_;
>  	void doAlsc();
> -	double lambdaR_[AlscCellsX * AlscCellsY];
> -	double lambdaB_[AlscCellsX * AlscCellsY];
> +	std::vector<double> lambdaR_;
> +	std::vector<double> lambdaB_;
> +
> +	/* Temporaries for the computations */
> +	std::array<std::vector<double>, 5> tmpC_;
> +	std::array<std::vector<std::array<double, 4>>, 3> tmpM_;
>  };
>
>  } /* namespace RPiController */
> diff --git a/src/ipa/raspberrypi/raspberrypi.cpp b/src/ipa/raspberrypi/raspberrypi.cpp
> index b64cb96e2dde..0fa79bb4af41 100644
> --- a/src/ipa/raspberrypi/raspberrypi.cpp
> +++ b/src/ipa/raspberrypi/raspberrypi.cpp
> @@ -13,6 +13,7 @@
>  #include <math.h>
>  #include <stdint.h>
>  #include <string.h>
> +#include <vector>

Should this be moved after <sys/mman.h> ?

>  #include <sys/mman.h>
>
>  #include <linux/bcm2835-isp.h>
> @@ -174,7 +175,7 @@ private:
>  	void applyDPC(const struct DpcStatus *dpcStatus, ControlList &ctrls);
>  	void applyLS(const struct AlscStatus *lsStatus, ControlList &ctrls);
>  	void applyAF(const struct AfStatus *afStatus, ControlList &lensCtrls);
> -	void resampleTable(uint16_t dest[], double const src[12][16], int destW, int destH);
> +	void resampleTable(uint16_t dest[], const std::vector<double> &src, int destW, int destH);
>
>  	std::map<unsigned int, MappedFrameBuffer> buffers_;
>
> @@ -1768,7 +1769,7 @@ void IPARPi::applyAF(const struct AfStatus *afStatus, ControlList &lensCtrls)
>   * Resamples a 16x12 table with central sampling to destW x destH with corner

The 16x12 size is mentioned here

>   * sampling.
>   */
> -void IPARPi::resampleTable(uint16_t dest[], double const src[12][16],
> +void IPARPi::resampleTable(uint16_t dest[], const std::vector<double> &src,
>  			   int destW, int destH)
>  {
>  	/*
> @@ -1793,8 +1794,8 @@ void IPARPi::resampleTable(uint16_t dest[], double const src[12][16],
>  		double yf = y - yLo;
>  		int yHi = yLo < 11 ? yLo + 1 : 11;
>  		yLo = yLo > 0 ? yLo : 0;
> -		double const *rowAbove = src[yLo];
> -		double const *rowBelow = src[yHi];
> +		double const *rowAbove = src.data() + yLo * 16;
> +		double const *rowBelow = src.data() + yHi * 16;

As well as assumed here. Also the previous index was yLo and the new
one (yLo * 16). Is it ok ?

>  		for (int i = 0; i < destW; i++) {
>  			double above = rowAbove[xLo[i]] * (1 - xf[i]) + rowAbove[xHi[i]] * xf[i];
>  			double below = rowBelow[xLo[i]] * (1 - xf[i]) + rowBelow[xHi[i]] * xf[i];
> --
> 2.34.1
>


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