root/modules/cudaoptflow/src/farneback.cpp

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DEFINITIONS

This source file includes following definitions.
  1. create
  2. flags_
  3. getNumLevels
  4. setNumLevels
  5. getPyrScale
  6. setPyrScale
  7. getFastPyramids
  8. setFastPyramids
  9. getWinSize
  10. setWinSize
  11. getNumIters
  12. setNumIters
  13. getPolyN
  14. setPolyN
  15. getPolySigma
  16. setPolySigma
  17. getFlags
  18. setFlags
  19. calc
  20. allocMatFromBuf
  21. prepareGaussian
  22. setPolynomialExpansionConsts
  23. updateFlow_boxFilter
  24. updateFlow_gaussianBlur
  25. calcImpl
  26. create

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#include "precomp.hpp"

using namespace cv;
using namespace cv::cuda;

#if !defined HAVE_CUDA || defined(CUDA_DISABLER)

Ptr<FarnebackOpticalFlow> cv::cuda::FarnebackOpticalFlow::create(int, double, bool, int, int, int, double, int) { throw_no_cuda(); return Ptr<BroxOpticalFlow>(); }

#else

#define MIN_SIZE 32

// CUDA resize() is fast, but it differs from the CPU analog. Disabling this flag
// leads to an inefficient code. It's for debug purposes only.
#define ENABLE_CUDA_RESIZE 1

namespace cv { namespace cuda { namespace device { namespace optflow_farneback
{
    void setPolynomialExpansionConsts(
            int polyN, const float *g, const float *xg, const float *xxg,
            float ig11, float ig03, float ig33, float ig55);

    void polynomialExpansionGpu(const PtrStepSzf &src, int polyN, PtrStepSzf dst, cudaStream_t stream);

    void setUpdateMatricesConsts();

    void updateMatricesGpu(
            const PtrStepSzf flowx, const PtrStepSzf flowy, const PtrStepSzf R0, const PtrStepSzf R1,
            PtrStepSzf M, cudaStream_t stream);

    void updateFlowGpu(
            const PtrStepSzf M, PtrStepSzf flowx, PtrStepSzf flowy, cudaStream_t stream);

    void boxFilter5Gpu(const PtrStepSzf src, int ksizeHalf, PtrStepSzf dst, cudaStream_t stream);

    void boxFilter5Gpu_CC11(const PtrStepSzf src, int ksizeHalf, PtrStepSzf dst, cudaStream_t stream);

    void setGaussianBlurKernel(const float *gKer, int ksizeHalf);

    void gaussianBlurGpu(
            const PtrStepSzf src, int ksizeHalf, PtrStepSzf dst, int borderType, cudaStream_t stream);

    void gaussianBlur5Gpu(
            const PtrStepSzf src, int ksizeHalf, PtrStepSzf dst, int borderType, cudaStream_t stream);

    void gaussianBlur5Gpu_CC11(
            const PtrStepSzf src, int ksizeHalf, PtrStepSzf dst, int borderType, cudaStream_t stream);

}}}}

namespace
{
    class FarnebackOpticalFlowImpl : public FarnebackOpticalFlow
    {
    public:
        FarnebackOpticalFlowImpl(int numLevels, double pyrScale, bool fastPyramids, int winSize,
                                 int numIters, int polyN, double polySigma, int flags) :
            numLevels_(numLevels), pyrScale_(pyrScale), fastPyramids_(fastPyramids), winSize_(winSize),
            numIters_(numIters), polyN_(polyN), polySigma_(polySigma), flags_(flags)
        {
        }

        virtual int getNumLevels() const { return numLevels_; }
        virtual void setNumLevels(int numLevels) { numLevels_ = numLevels; }

        virtual double getPyrScale() const { return pyrScale_; }
        virtual void setPyrScale(double pyrScale) { pyrScale_ = pyrScale; }

        virtual bool getFastPyramids() const { return fastPyramids_; }
        virtual void setFastPyramids(bool fastPyramids) { fastPyramids_ = fastPyramids; }

        virtual int getWinSize() const { return winSize_; }
        virtual void setWinSize(int winSize) { winSize_ = winSize; }

        virtual int getNumIters() const { return numIters_; }
        virtual void setNumIters(int numIters) { numIters_ = numIters; }

        virtual int getPolyN() const { return polyN_; }
        virtual void setPolyN(int polyN) { polyN_ = polyN; }

        virtual double getPolySigma() const { return polySigma_; }
        virtual void setPolySigma(double polySigma) { polySigma_ = polySigma; }

        virtual int getFlags() const { return flags_; }
        virtual void setFlags(int flags) { flags_ = flags; }

        virtual void calc(InputArray I0, InputArray I1, InputOutputArray flow, Stream& stream);

    private:
        int numLevels_;
        double pyrScale_;
        bool fastPyramids_;
        int winSize_;
        int numIters_;
        int polyN_;
        double polySigma_;
        int flags_;

    private:
        void prepareGaussian(
                int n, double sigma, float *g, float *xg, float *xxg,
                double &ig11, double &ig03, double &ig33, double &ig55);

        void setPolynomialExpansionConsts(int n, double sigma);

        void updateFlow_boxFilter(
                const GpuMat& R0, const GpuMat& R1, GpuMat& flowx, GpuMat &flowy,
                GpuMat& M, GpuMat &bufM, int blockSize, bool updateMatrices, Stream streams[]);

        void updateFlow_gaussianBlur(
                const GpuMat& R0, const GpuMat& R1, GpuMat& flowx, GpuMat& flowy,
                GpuMat& M, GpuMat &bufM, int blockSize, bool updateMatrices, Stream streams[]);

        void calcImpl(const GpuMat &frame0, const GpuMat &frame1, GpuMat &flowx, GpuMat &flowy, Stream &stream);

        GpuMat frames_[2];
        GpuMat pyrLevel_[2], M_, bufM_, R_[2], blurredFrame_[2];
        std::vector<GpuMat> pyramid0_, pyramid1_;
    };

    void FarnebackOpticalFlowImpl::calc(InputArray _frame0, InputArray _frame1, InputOutputArray _flow, Stream& stream)
    {
        const GpuMat frame0 = _frame0.getGpuMat();
        const GpuMat frame1 = _frame1.getGpuMat();

        BufferPool pool(stream);
        GpuMat flowx = pool.getBuffer(frame0.size(), CV_32FC1);
        GpuMat flowy = pool.getBuffer(frame0.size(), CV_32FC1);

        calcImpl(frame0, frame1, flowx, flowy, stream);

        GpuMat flows[] = {flowx, flowy};
        cuda::merge(flows, 2, _flow, stream);
    }

    GpuMat allocMatFromBuf(int rows, int cols, int type, GpuMat& mat)
    {
        if (!mat.empty() && mat.type() == type && mat.rows >= rows && mat.cols >= cols)
            return mat(Rect(0, 0, cols, rows));

        return mat = GpuMat(rows, cols, type);
    }

    void FarnebackOpticalFlowImpl::prepareGaussian(
            int n, double sigma, float *g, float *xg, float *xxg,
            double &ig11, double &ig03, double &ig33, double &ig55)
    {
        double s = 0.;
        for (int x = -n; x <= n; x++)
        {
            g[x] = (float)std::exp(-x*x/(2*sigma*sigma));
            s += g[x];
        }

        s = 1./s;
        for (int x = -n; x <= n; x++)
        {
            g[x] = (float)(g[x]*s);
            xg[x] = (float)(x*g[x]);
            xxg[x] = (float)(x*x*g[x]);
        }

        Mat_<double> G(6, 6);
        G.setTo(0);

        for (int y = -n; y <= n; y++)
        {
            for (int x = -n; x <= n; x++)
            {
                G(0,0) += g[y]*g[x];
                G(1,1) += g[y]*g[x]*x*x;
                G(3,3) += g[y]*g[x]*x*x*x*x;
                G(5,5) += g[y]*g[x]*x*x*y*y;
            }
        }

        //G[0][0] = 1.;
        G(2,2) = G(0,3) = G(0,4) = G(3,0) = G(4,0) = G(1,1);
        G(4,4) = G(3,3);
        G(3,4) = G(4,3) = G(5,5);

        // invG:
        // [ x        e  e    ]
        // [    y             ]
        // [       y          ]
        // [ e        z       ]
        // [ e           z    ]
        // [                u ]
        Mat_<double> invG = G.inv(DECOMP_CHOLESKY);

        ig11 = invG(1,1);
        ig03 = invG(0,3);
        ig33 = invG(3,3);
        ig55 = invG(5,5);
    }

    void FarnebackOpticalFlowImpl::setPolynomialExpansionConsts(int n, double sigma)
    {
        std::vector<float> buf(n*6 + 3);
        float* g = &buf[0] + n;
        float* xg = g + n*2 + 1;
        float* xxg = xg + n*2 + 1;

        if (sigma < FLT_EPSILON)
            sigma = n*0.3;

        double ig11, ig03, ig33, ig55;
        prepareGaussian(n, sigma, g, xg, xxg, ig11, ig03, ig33, ig55);

        device::optflow_farneback::setPolynomialExpansionConsts(n, g, xg, xxg, static_cast<float>(ig11), static_cast<float>(ig03), static_cast<float>(ig33), static_cast<float>(ig55));
    }

    void FarnebackOpticalFlowImpl::updateFlow_boxFilter(
            const GpuMat& R0, const GpuMat& R1, GpuMat& flowx, GpuMat &flowy,
            GpuMat& M, GpuMat &bufM, int blockSize, bool updateMatrices, Stream streams[])
    {
        if (deviceSupports(FEATURE_SET_COMPUTE_12))
            device::optflow_farneback::boxFilter5Gpu(M, blockSize/2, bufM, StreamAccessor::getStream(streams[0]));
        else
            device::optflow_farneback::boxFilter5Gpu_CC11(M, blockSize/2, bufM, StreamAccessor::getStream(streams[0]));
        swap(M, bufM);

        for (int i = 1; i < 5; ++i)
            streams[i].waitForCompletion();
        device::optflow_farneback::updateFlowGpu(M, flowx, flowy, StreamAccessor::getStream(streams[0]));

        if (updateMatrices)
            device::optflow_farneback::updateMatricesGpu(flowx, flowy, R0, R1, M, StreamAccessor::getStream(streams[0]));
    }

    void FarnebackOpticalFlowImpl::updateFlow_gaussianBlur(
            const GpuMat& R0, const GpuMat& R1, GpuMat& flowx, GpuMat& flowy,
            GpuMat& M, GpuMat &bufM, int blockSize, bool updateMatrices, Stream streams[])
    {
        if (deviceSupports(FEATURE_SET_COMPUTE_12))
            device::optflow_farneback::gaussianBlur5Gpu(
                        M, blockSize/2, bufM, BORDER_REPLICATE, StreamAccessor::getStream(streams[0]));
        else
            device::optflow_farneback::gaussianBlur5Gpu_CC11(
                        M, blockSize/2, bufM, BORDER_REPLICATE, StreamAccessor::getStream(streams[0]));
        swap(M, bufM);

        device::optflow_farneback::updateFlowGpu(M, flowx, flowy, StreamAccessor::getStream(streams[0]));

        if (updateMatrices)
            device::optflow_farneback::updateMatricesGpu(flowx, flowy, R0, R1, M, StreamAccessor::getStream(streams[0]));
    }

    void FarnebackOpticalFlowImpl::calcImpl(const GpuMat &frame0, const GpuMat &frame1, GpuMat &flowx, GpuMat &flowy, Stream &stream)
    {
        CV_Assert(frame0.channels() == 1 && frame1.channels() == 1);
        CV_Assert(frame0.size() == frame1.size());
        CV_Assert(polyN_ == 5 || polyN_ == 7);
        CV_Assert(!fastPyramids_ || std::abs(pyrScale_ - 0.5) < 1e-6);

        Stream streams[5];
        if (stream)
            streams[0] = stream;

        Size size = frame0.size();
        GpuMat prevFlowX, prevFlowY, curFlowX, curFlowY;

        flowx.create(size, CV_32F);
        flowy.create(size, CV_32F);
        GpuMat flowx0 = flowx;
        GpuMat flowy0 = flowy;

        // Crop unnecessary levels
        double scale = 1;
        int numLevelsCropped = 0;
        for (; numLevelsCropped < numLevels_; numLevelsCropped++)
        {
            scale *= pyrScale_;
            if (size.width*scale < MIN_SIZE || size.height*scale < MIN_SIZE)
                break;
        }

        frame0.convertTo(frames_[0], CV_32F, streams[0]);
        frame1.convertTo(frames_[1], CV_32F, streams[1]);

        if (fastPyramids_)
        {
            // Build Gaussian pyramids using pyrDown()
            pyramid0_.resize(numLevelsCropped + 1);
            pyramid1_.resize(numLevelsCropped + 1);
            pyramid0_[0] = frames_[0];
            pyramid1_[0] = frames_[1];
            for (int i = 1; i <= numLevelsCropped; ++i)
            {
                cuda::pyrDown(pyramid0_[i - 1], pyramid0_[i], streams[0]);
                cuda::pyrDown(pyramid1_[i - 1], pyramid1_[i], streams[1]);
            }
        }

        setPolynomialExpansionConsts(polyN_, polySigma_);
        device::optflow_farneback::setUpdateMatricesConsts();

        for (int k = numLevelsCropped; k >= 0; k--)
        {
            streams[0].waitForCompletion();

            scale = 1;
            for (int i = 0; i < k; i++)
                scale *= pyrScale_;

            double sigma = (1./scale - 1) * 0.5;
            int smoothSize = cvRound(sigma*5) | 1;
            smoothSize = std::max(smoothSize, 3);

            int width = cvRound(size.width*scale);
            int height = cvRound(size.height*scale);

            if (fastPyramids_)
            {
                width = pyramid0_[k].cols;
                height = pyramid0_[k].rows;
            }

            if (k > 0)
            {
                curFlowX.create(height, width, CV_32F);
                curFlowY.create(height, width, CV_32F);
            }
            else
            {
                curFlowX = flowx0;
                curFlowY = flowy0;
            }

            if (!prevFlowX.data)
            {
                if (flags_ & OPTFLOW_USE_INITIAL_FLOW)
                {
                    cuda::resize(flowx0, curFlowX, Size(width, height), 0, 0, INTER_LINEAR, streams[0]);
                    cuda::resize(flowy0, curFlowY, Size(width, height), 0, 0, INTER_LINEAR, streams[1]);
                    curFlowX.convertTo(curFlowX, curFlowX.depth(), scale, streams[0]);
                    curFlowY.convertTo(curFlowY, curFlowY.depth(), scale, streams[1]);
                }
                else
                {
                    curFlowX.setTo(0, streams[0]);
                    curFlowY.setTo(0, streams[1]);
                }
            }
            else
            {
                cuda::resize(prevFlowX, curFlowX, Size(width, height), 0, 0, INTER_LINEAR, streams[0]);
                cuda::resize(prevFlowY, curFlowY, Size(width, height), 0, 0, INTER_LINEAR, streams[1]);
                curFlowX.convertTo(curFlowX, curFlowX.depth(), 1./pyrScale_, streams[0]);
                curFlowY.convertTo(curFlowY, curFlowY.depth(), 1./pyrScale_, streams[1]);
            }

            GpuMat M = allocMatFromBuf(5*height, width, CV_32F, M_);
            GpuMat bufM = allocMatFromBuf(5*height, width, CV_32F, bufM_);
            GpuMat R[2] =
            {
                allocMatFromBuf(5*height, width, CV_32F, R_[0]),
                allocMatFromBuf(5*height, width, CV_32F, R_[1])
            };

            if (fastPyramids_)
            {
                device::optflow_farneback::polynomialExpansionGpu(pyramid0_[k], polyN_, R[0], StreamAccessor::getStream(streams[0]));
                device::optflow_farneback::polynomialExpansionGpu(pyramid1_[k], polyN_, R[1], StreamAccessor::getStream(streams[1]));
            }
            else
            {
                GpuMat blurredFrame[2] =
                {
                    allocMatFromBuf(size.height, size.width, CV_32F, blurredFrame_[0]),
                    allocMatFromBuf(size.height, size.width, CV_32F, blurredFrame_[1])
                };
                GpuMat pyrLevel[2] =
                {
                    allocMatFromBuf(height, width, CV_32F, pyrLevel_[0]),
                    allocMatFromBuf(height, width, CV_32F, pyrLevel_[1])
                };

                Mat g = getGaussianKernel(smoothSize, sigma, CV_32F);
                device::optflow_farneback::setGaussianBlurKernel(g.ptr<float>(smoothSize/2), smoothSize/2);

                for (int i = 0; i < 2; i++)
                {
                    device::optflow_farneback::gaussianBlurGpu(
                            frames_[i], smoothSize/2, blurredFrame[i], BORDER_REFLECT101, StreamAccessor::getStream(streams[i]));
                    cuda::resize(blurredFrame[i], pyrLevel[i], Size(width, height), 0.0, 0.0, INTER_LINEAR, streams[i]);
                    device::optflow_farneback::polynomialExpansionGpu(pyrLevel[i], polyN_, R[i], StreamAccessor::getStream(streams[i]));
                }
            }

            streams[1].waitForCompletion();
            device::optflow_farneback::updateMatricesGpu(curFlowX, curFlowY, R[0], R[1], M, StreamAccessor::getStream(streams[0]));

            if (flags_ & OPTFLOW_FARNEBACK_GAUSSIAN)
            {
                Mat g = getGaussianKernel(winSize_, winSize_/2*0.3f, CV_32F);
                device::optflow_farneback::setGaussianBlurKernel(g.ptr<float>(winSize_/2), winSize_/2);
            }
            for (int i = 0; i < numIters_; i++)
            {
                if (flags_ & OPTFLOW_FARNEBACK_GAUSSIAN)
                    updateFlow_gaussianBlur(R[0], R[1], curFlowX, curFlowY, M, bufM, winSize_, i < numIters_-1, streams);
                else
                    updateFlow_boxFilter(R[0], R[1], curFlowX, curFlowY, M, bufM, winSize_, i < numIters_-1, streams);
            }

            prevFlowX = curFlowX;
            prevFlowY = curFlowY;
        }

        flowx = curFlowX;
        flowy = curFlowY;

        if (!stream)
            streams[0].waitForCompletion();
    }
}

Ptr<FarnebackOpticalFlow> cv::cuda::FarnebackOpticalFlow::create(int numLevels, double pyrScale, bool fastPyramids, int winSize,
                                                                 int numIters, int polyN, double polySigma, int flags)
{
    return makePtr<FarnebackOpticalFlowImpl>(numLevels, pyrScale, fastPyramids, winSize,
                                             numIters, polyN, polySigma, flags);
}

#endif

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