fast optical flow bm implementation

modules/gpu/app/nv_perf_test/main.cpp

@@ -94,13 +94,13 @@ PERF_TEST_P(Image, HoughLinesP,
     {
         cv::gpu::GpuMat d_image(image);
         cv::gpu::GpuMat d_lines;
-        cv::gpu::CannyBuf d_buf;
+        cv::gpu::HoughLinesBuf d_buf;
 
-        cv::gpu::HoughLinesP(d_image, d_lines, d_buf, minLineLenght, maxLineGap);
+        cv::gpu::HoughLinesP(d_image, d_lines, d_buf, rho, theta, minLineLenght, maxLineGap);
 
         TEST_CYCLE()
         {
-            cv::gpu::HoughLinesP(d_image, d_lines, d_buf, minLineLenght, maxLineGap);
+            cv::gpu::HoughLinesP(d_image, d_lines, d_buf, rho, theta, minLineLenght, maxLineGap);
         }
     }
     else
@@ -434,3 +434,56 @@ PERF_TEST_P(ImagePair_BlockSize_ShiftSize_MaxRange, OpticalFlowBM,
 
     SANITY_CHECK(0);
 }
+
+PERF_TEST_P(ImagePair_BlockSize_ShiftSize_MaxRange, FastOpticalFlowBM,
+            testing::Combine(
+                testing::Values(string_pair("im1_1280x800.jpg", "im2_1280x800.jpg")),
+                testing::Values(cv::Size(16, 16)),
+                testing::Values(cv::Size(1, 1)),
+                testing::Values(cv::Size(16, 16))
+                ))
+{
+    declare.time(1000);
+
+    const string_pair fileNames = std::tr1::get<0>(GetParam());
+    const cv::Size block_size = std::tr1::get<1>(GetParam());
+    const cv::Size shift_size = std::tr1::get<2>(GetParam());
+    const cv::Size max_range = std::tr1::get<3>(GetParam());
+
+    cv::Mat src1 = cv::imread(fileNames.first, cv::IMREAD_GRAYSCALE);
+    if (src1.empty())
+        FAIL() << "Unable to load source image [" << fileNames.first << "]";
+
+    cv::Mat src2 = cv::imread(fileNames.second, cv::IMREAD_GRAYSCALE);
+    if (src2.empty())
+        FAIL() << "Unable to load source image [" << fileNames.second << "]";
+
+    if (PERF_RUN_GPU())
+    {
+        cv::gpu::GpuMat d_src1(src1);
+        cv::gpu::GpuMat d_src2(src2);
+        cv::gpu::GpuMat d_velx, d_vely;
+
+        cv::gpu::FastOpticalFlowBM fastBM;
+
+        fastBM(d_src1, d_src2, d_velx, d_vely, max_range.width, block_size.width);
+
+        TEST_CYCLE_N(10)
+        {
+            fastBM(d_src1, d_src2, d_velx, d_vely, max_range.width, block_size.width);
+        }
+    }
+    else
+    {
+        cv::Mat velx, vely;
+
+        calcOpticalFlowBM(src1, src2, block_size, shift_size, max_range, false, velx, vely);
+
+        TEST_CYCLE_N(10)
+        {
+            calcOpticalFlowBM(src1, src2, block_size, shift_size, max_range, false, velx, vely);
+        }
+    }
+
+    SANITY_CHECK(0);
+}

modules/gpu/include/opencv2/gpu/gpu.hpp

@@ -2129,6 +2129,17 @@ CV_EXPORTS void calcOpticalFlowBM(const GpuMat& prev, const GpuMat& curr,
                                   GpuMat& velx, GpuMat& vely, GpuMat& buf,
                                   Stream& stream = Stream::Null());
 
+class CV_EXPORTS FastOpticalFlowBM
+{
+public:
+    void operator ()(const GpuMat& I0, const GpuMat& I1, GpuMat& flowx, GpuMat& flowy, int search_window = 21, int block_window = 7, Stream& s = Stream::Null());
+
+private:
+    GpuMat buffer;
+    GpuMat extended_I0;
+    GpuMat extended_I1;
+};
+
 
 //! Interpolate frames (images) using provided optical flow (displacement field).
 //! frame0   - frame 0 (32-bit floating point images, single channel)

modules/gpu/perf/perf_video.cpp

@@ -512,6 +512,55 @@ PERF_TEST_P(ImagePair, Video_OpticalFlowBM,
     }
 }
 
+PERF_TEST_P(ImagePair, Video_FastOpticalFlowBM,
+    Values<pair_string>(make_pair("gpu/opticalflow/frame0.png", "gpu/opticalflow/frame1.png")))
+{
+    declare.time(400);
+
+    cv::Mat frame0 = readImage(GetParam().first, cv::IMREAD_GRAYSCALE);
+    ASSERT_FALSE(frame0.empty());
+
+    cv::Mat frame1 = readImage(GetParam().second, cv::IMREAD_GRAYSCALE);
+    ASSERT_FALSE(frame1.empty());
+
+    cv::Size block_size(16, 16);
+    cv::Size shift_size(1, 1);
+    cv::Size max_range(16, 16);
+
+    if (PERF_RUN_GPU())
+    {
+        cv::gpu::GpuMat d_frame0(frame0);
+        cv::gpu::GpuMat d_frame1(frame1);
+        cv::gpu::GpuMat d_velx, d_vely;
+
+        cv::gpu::FastOpticalFlowBM fastBM;
+
+        fastBM(d_frame0, d_frame1, d_velx, d_vely, max_range.width, block_size.width);
+
+        TEST_CYCLE()
+        {
+            fastBM(d_frame0, d_frame1, d_velx, d_vely, max_range.width, block_size.width);
+        }
+
+        GPU_SANITY_CHECK(d_velx);
+        GPU_SANITY_CHECK(d_vely);
+    }
+    else
+    {
+        cv::Mat velx, vely;
+
+        calcOpticalFlowBM(frame0, frame1, block_size, shift_size, max_range, false, velx, vely);
+
+        TEST_CYCLE()
+        {
+            calcOpticalFlowBM(frame0, frame1, block_size, shift_size, max_range, false, velx, vely);
+        }
+
+        CPU_SANITY_CHECK(velx);
+        CPU_SANITY_CHECK(vely);
+    }
+}
+
 //////////////////////////////////////////////////////
 // FGDStatModel
 

modules/gpu/src/cuda/optflowbm.cu

@@ -44,6 +44,8 @@
 
 #include "opencv2/gpu/device/common.hpp"
 #include "opencv2/gpu/device/limits.hpp"
+#include "opencv2/gpu/device/functional.hpp"
+#include "opencv2/gpu/device/reduce.hpp"
 
 using namespace cv::gpu;
 using namespace cv::gpu::device;
@@ -164,4 +166,249 @@ namespace optflowbm
     }
 }
 
+/////////////////////////////////////////////////////////
+// Fast approximate version
+
+namespace optflowbm_fast
+{
+    enum
+    {
+        CTA_SIZE = 128,
+
+        TILE_COLS = 128,
+        TILE_ROWS = 32,
+
+        STRIDE = CTA_SIZE
+    };
+
+    template <typename T> __device__ __forceinline__ int calcDist(T a, T b)
+    {
+        return ::abs(a - b);
+    }
+
+    template <class T> struct FastOptFlowBM
+    {
+
+        int search_radius;
+        int block_radius;
+
+        int search_window;
+        int block_window;
+
+        PtrStepSz<T> I0;
+        PtrStep<T> I1;
+
+        mutable PtrStepi buffer;
+
+        FastOptFlowBM(int search_window_, int block_window_,
+                      PtrStepSz<T> I0_, PtrStepSz<T> I1_,
+                      PtrStepi buffer_) :
+            search_radius(search_window_ / 2), block_radius(block_window_ / 2),
+            search_window(search_window_), block_window(block_window_),
+            I0(I0_), I1(I1_),
+            buffer(buffer_)
+        {
+        }
+
+        __device__ void initSums_BruteForce(int i, int j, int* dist_sums, PtrStepi& col_sums, PtrStepi& up_col_sums) const
+        {
+            for (int index = threadIdx.x; index < search_window * search_window; index += STRIDE)
+            {
+                dist_sums[index] = 0;
+
+                for (int tx = 0; tx < block_window; ++tx)
+                    col_sums(tx, index) = 0;
+
+                int y = index / search_window;
+                int x = index - y * search_window;
+
+                int ay = i;
+                int ax = j;
+
+                int by = i + y - search_radius;
+                int bx = j + x - search_radius;
+
+                for (int tx = -block_radius; tx <= block_radius; ++tx)
+                {
+                    int col_sum = 0;
+                    for (int ty = -block_radius; ty <= block_radius; ++ty)
+                    {
+                        int dist = calcDist(I0(ay + ty, ax + tx), I1(by + ty, bx + tx));
+
+                        dist_sums[index] += dist;
+                        col_sum += dist;
+                    }
+
+                    col_sums(tx + block_radius, index) = col_sum;
+                }
+
+                up_col_sums(j, index) = col_sums(block_window - 1, index);
+            }
+        }
+
+        __device__ void shiftRight_FirstRow(int i, int j, int first, int* dist_sums, PtrStepi& col_sums, PtrStepi& up_col_sums) const
+        {
+            for (int index = threadIdx.x; index < search_window * search_window; index += STRIDE)
+            {
+                int y = index / search_window;
+                int x = index - y * search_window;
+
+                int ay = i;
+                int ax = j + block_radius;
+
+                int by = i + y - search_radius;
+                int bx = j + x - search_radius + block_radius;
+
+                int col_sum = 0;
+
+                for (int ty = -block_radius; ty <= block_radius; ++ty)
+                    col_sum += calcDist(I0(ay + ty, ax), I1(by + ty, bx));
+
+                dist_sums[index] += col_sum - col_sums(first, index);
+
+                col_sums(first, index) = col_sum;
+                up_col_sums(j, index) = col_sum;
+            }
+        }
+
+        __device__ void shiftRight_UpSums(int i, int j, int first, int* dist_sums, PtrStepi& col_sums, PtrStepi& up_col_sums) const
+        {
+            int ay = i;
+            int ax = j + block_radius;
+
+            T a_up   = I0(ay - block_radius - 1, ax);
+            T a_down = I0(ay + block_radius, ax);
+
+            for(int index = threadIdx.x; index < search_window * search_window; index += STRIDE)
+            {
+                int y = index / search_window;
+                int x = index - y * search_window;
+
+                int by = i + y - search_radius;
+                int bx = j + x - search_radius + block_radius;
+
+                T b_up   = I1(by - block_radius - 1, bx);
+                T b_down = I1(by + block_radius, bx);
+
+                int col_sum = up_col_sums(j, index) + calcDist(a_down, b_down) - calcDist(a_up, b_up);
+
+                dist_sums[index] += col_sum  - col_sums(first, index);
+                col_sums(first, index) = col_sum;
+                up_col_sums(j, index) = col_sum;
+            }
+        }
+
+        __device__ void convolve_window(int i, int j, const int* dist_sums, float& velx, float& vely) const
+        {
+            int bestDist = numeric_limits<int>::max();
+            int bestInd = -1;
+
+            for (int index = threadIdx.x; index < search_window * search_window; index += STRIDE)
+            {
+                int curDist = dist_sums[index];
+                if (curDist < bestDist)
+                {
+                    bestDist = curDist;
+                    bestInd = index;
+                }
+            }
+
+            __shared__ int cta_dist_buffer[CTA_SIZE];
+            __shared__ int cta_ind_buffer[CTA_SIZE];
+
+            reduceKeyVal<CTA_SIZE>(cta_dist_buffer, bestDist, cta_ind_buffer, bestInd, threadIdx.x, less<int>());
+
+            if (threadIdx.x == 0)
+            {
+                int y = bestInd / search_window;
+                int x = bestInd - y * search_window;
+
+                velx = x - search_radius;
+                vely = y - search_radius;
+            }
+        }
+
+        __device__ void operator()(PtrStepf velx, PtrStepf vely) const
+        {
+            int tbx = blockIdx.x * TILE_COLS;
+            int tby = blockIdx.y * TILE_ROWS;
+
+            int tex = ::min(tbx + TILE_COLS, I0.cols);
+            int tey = ::min(tby + TILE_ROWS, I0.rows);
+
+            PtrStepi col_sums;
+            col_sums.data = buffer.ptr(I0.cols + blockIdx.x * block_window) + blockIdx.y * search_window * search_window;
+            col_sums.step = buffer.step;
+
+            PtrStepi up_col_sums;
+            up_col_sums.data = buffer.data + blockIdx.y * search_window * search_window;
+            up_col_sums.step = buffer.step;
+
+            extern __shared__ int dist_sums[]; //search_window * search_window
+
+            int first = 0;
+
+            for (int i = tby; i < tey; ++i)
+            {
+                for (int j = tbx; j < tex; ++j)
+                {
+                    __syncthreads();
+
+                    if (j == tbx)
+                    {
+                        initSums_BruteForce(i, j, dist_sums, col_sums, up_col_sums);
+                        first = 0;
+                    }
+                    else
+                    {
+                        if (i == tby)
+                          shiftRight_FirstRow(i, j, first, dist_sums, col_sums, up_col_sums);
+                        else
+                          shiftRight_UpSums(i, j, first, dist_sums, col_sums, up_col_sums);
+
+                        first = (first + 1) % block_window;
+                    }
+
+                    __syncthreads();
+
+                    convolve_window(i, j, dist_sums, velx(i, j), vely(i, j));
+                }
+            }
+        }
+
+    };
+
+    template<typename T> __global__ void optflowbm_fast_kernel(const FastOptFlowBM<T> fbm, PtrStepf velx, PtrStepf vely)
+    {
+        fbm(velx, vely);
+    }
+
+    void get_buffer_size(int src_cols, int src_rows, int search_window, int block_window, int& buffer_cols, int& buffer_rows)
+    {
+        dim3 grid(divUp(src_cols, TILE_COLS), divUp(src_rows, TILE_ROWS));
+
+        buffer_cols = search_window * search_window * grid.y;
+        buffer_rows = src_cols + block_window * grid.x;
+    }
+
+    template <typename T>
+    void calc(PtrStepSzb I0, PtrStepSzb I1, PtrStepSzf velx, PtrStepSzf vely, PtrStepi buffer, int search_window, int block_window, cudaStream_t stream)
+    {
+        FastOptFlowBM<T> fbm(search_window, block_window, I0, I1, buffer);
+
+        dim3 block(CTA_SIZE, 1);
+        dim3 grid(divUp(I0.cols, TILE_COLS), divUp(I0.rows, TILE_ROWS));
+
+        size_t smem = search_window * search_window * sizeof(int);
+
+        optflowbm_fast_kernel<<<grid, block, smem, stream>>>(fbm, velx, vely);
+        cudaSafeCall ( cudaGetLastError () );
+
+        if (stream == 0)
+            cudaSafeCall( cudaDeviceSynchronize() );
+    }
+
+    template void calc<uchar>(PtrStepSzb I0, PtrStepSzb I1, PtrStepSzf velx, PtrStepSzf vely, PtrStepi buffer, int search_window, int block_window, cudaStream_t stream);
+}
+
 #endif // !defined CUDA_DISABLER

modules/gpu/src/optflowbm.cpp

@@ -50,6 +50,8 @@ using namespace cv::gpu;
 
 void cv::gpu::calcOpticalFlowBM(const GpuMat&, const GpuMat&, Size, Size, Size, bool, GpuMat&, GpuMat&, GpuMat&, Stream&) { throw_nogpu(); }
 
+void cv::gpu::FastOpticalFlowBM::operator ()(const GpuMat&, const GpuMat&, GpuMat&, GpuMat&, int, int, Stream&) { throw_nogpu(); }
+
 #else // HAVE_CUDA
 
 namespace optflowbm
@@ -202,4 +204,40 @@ void cv::gpu::calcOpticalFlowBM(const GpuMat& prev, const GpuMat& curr, Size blo
                     maxX, maxY, acceptLevel, escapeLevel, buf.ptr<short2>(), ssCount, stream);
 }
 
+namespace optflowbm_fast
+{
+    void get_buffer_size(int src_cols, int src_rows, int search_window, int block_window, int& buffer_cols, int& buffer_rows);
+
+    template <typename T>
+    void calc(PtrStepSzb I0, PtrStepSzb I1, PtrStepSzf velx, PtrStepSzf vely, PtrStepi buffer, int search_window, int block_window, cudaStream_t stream);
+}
+
+void cv::gpu::FastOpticalFlowBM::operator ()(const GpuMat& I0, const GpuMat& I1, GpuMat& flowx, GpuMat& flowy, int search_window, int block_window, Stream& stream)
+{
+    CV_Assert( I0.type() == CV_8UC1 );
+    CV_Assert( I1.size() == I0.size() && I1.type() == I0.type() );
+
+    int border_size = search_window / 2 + block_window / 2;
+    Size esize = I0.size() + Size(border_size, border_size) * 2;
+
+    ensureSizeIsEnough(esize, I0.type(), extended_I0);
+    ensureSizeIsEnough(esize, I0.type(), extended_I1);
+
+    copyMakeBorder(I0, extended_I0, border_size, border_size, border_size, border_size, cv::BORDER_DEFAULT, Scalar(), stream);
+    copyMakeBorder(I1, extended_I1, border_size, border_size, border_size, border_size, cv::BORDER_DEFAULT, Scalar(), stream);
+
+    GpuMat I0_hdr = extended_I0(Rect(Point2i(border_size, border_size), I0.size()));
+    GpuMat I1_hdr = extended_I1(Rect(Point2i(border_size, border_size), I0.size()));
+
+    int bcols, brows;
+    optflowbm_fast::get_buffer_size(I0.cols, I0.rows, search_window, block_window, bcols, brows);
+
+    ensureSizeIsEnough(brows, bcols, CV_32SC1, buffer);
+
+    flowx.create(I0.size(), CV_32FC1);
+    flowy.create(I0.size(), CV_32FC1);
+
+    optflowbm_fast::calc<uchar>(I0_hdr, I1_hdr, flowx, flowy, buffer, search_window, block_window, StreamAccessor::getStream(stream));
+}
+
 #endif // HAVE_CUDA

modules/gpu/test/test_video.cpp

@@ -513,6 +513,121 @@ TEST_P(OpticalFlowBM, Accuracy)
 
 INSTANTIATE_TEST_CASE_P(GPU_Video, OpticalFlowBM, ALL_DEVICES);
 
+//////////////////////////////////////////////////////
+// FastOpticalFlowBM
+
+static void FastOpticalFlowBM_gold(const cv::Mat_<uchar>& I0, const cv::Mat_<uchar>& I1, cv::Mat_<float>& velx, cv::Mat_<float>& vely, int search_window, int block_window)
+{
+    velx.create(I0.size());
+    vely.create(I0.size());
+
+    int search_radius = search_window / 2;
+    int block_radius = block_window / 2;
+
+    for (int y = 0; y < I0.rows; ++y)
+    {
+        for (int x = 0; x < I0.cols; ++x)
+        {
+            int bestDist = std::numeric_limits<int>::max();
+            int bestDx = 0;
+            int bestDy = 0;
+
+            for (int dy = -search_radius; dy <= search_radius; ++dy)
+            {
+                for (int dx = -search_radius; dx <= search_radius; ++dx)
+                {
+                    int dist = 0;
+
+                    for (int by = -block_radius; by <= block_radius; ++by)
+                    {
+                        for (int bx = -block_radius; bx <= block_radius; ++bx)
+                        {
+                            int I0_val = I0(cv::borderInterpolate(y + by, I0.rows, cv::BORDER_DEFAULT), cv::borderInterpolate(x + bx, I0.cols, cv::BORDER_DEFAULT));
+                            int I1_val = I1(cv::borderInterpolate(y + dy + by, I0.rows, cv::BORDER_DEFAULT), cv::borderInterpolate(x + dx + bx, I0.cols, cv::BORDER_DEFAULT));
+
+                            dist += std::abs(I0_val - I1_val);
+                        }
+                    }
+
+                    if (dist < bestDist)
+                    {
+                        bestDist = dist;
+                        bestDx = dx;
+                        bestDy = dy;
+                    }
+                }
+            }
+
+            velx(y, x) = bestDx;
+            vely(y, x) = bestDy;
+        }
+    }
+}
+
+static double calc_rmse(const cv::Mat_<float>& flow1, const cv::Mat_<float>& flow2)
+{
+    double sum = 0.0;
+
+    for (int y = 0; y < flow1.rows; ++y)
+    {
+        for (int x = 0; x < flow1.cols; ++x)
+        {
+            double diff = flow1(y, x) - flow2(y, x);
+            sum += diff * diff;
+        }
+    }
+
+    return std::sqrt(sum / flow1.size().area());
+}
+
+struct FastOpticalFlowBM : testing::TestWithParam<cv::gpu::DeviceInfo>
+{
+};
+
+TEST_P(FastOpticalFlowBM, Accuracy)
+{
+    const double MAX_RMSE = 0.6;
+
+    int search_window = 15;
+    int block_window = 5;
+
+    cv::gpu::DeviceInfo devInfo = GetParam();
+    cv::gpu::setDevice(devInfo.deviceID());
+
+    cv::Mat frame0 = readImage("opticalflow/rubberwhale1.png", cv::IMREAD_GRAYSCALE);
+    ASSERT_FALSE(frame0.empty());
+
+    cv::Mat frame1 = readImage("opticalflow/rubberwhale2.png", cv::IMREAD_GRAYSCALE);
+    ASSERT_FALSE(frame1.empty());
+
+    cv::Size smallSize(320, 240);
+    cv::Mat frame0_small;
+    cv::Mat frame1_small;
+
+    cv::resize(frame0, frame0_small, smallSize);
+    cv::resize(frame1, frame1_small, smallSize);
+
+    cv::gpu::GpuMat d_flowx;
+    cv::gpu::GpuMat d_flowy;
+    cv::gpu::FastOpticalFlowBM fastBM;
+
+    fastBM(loadMat(frame0_small), loadMat(frame1_small), d_flowx, d_flowy, search_window, block_window);
+
+    cv::Mat_<float> flowx;
+    cv::Mat_<float> flowy;
+    FastOpticalFlowBM_gold(frame0_small, frame1_small, flowx, flowy, search_window, block_window);
+
+    double err;
+
+    err = calc_rmse(flowx, cv::Mat(d_flowx));
+    EXPECT_LE(err, MAX_RMSE);
+
+    err = calc_rmse(flowy, cv::Mat(d_flowy));
+    EXPECT_LE(err, MAX_RMSE);
+}
+
+INSTANTIATE_TEST_CASE_P(GPU_Video, FastOpticalFlowBM, ALL_DEVICES);
+
 //////////////////////////////////////////////////////
 // FGDStatModel
 

samples/gpu/optical_flow.cpp

@@ -121,6 +121,17 @@ static void drawOpticalFlow(const Mat_<float>& flowx, const Mat_<float>& flowy,
     }
 }
 
+static void showFlow(const char* name, const GpuMat& d_flowx, const GpuMat& d_flowy)
+{
+    Mat flowx(d_flowx);
+    Mat flowy(d_flowy);
+
+    Mat out;
+    drawOpticalFlow(flowx, flowy, out, 10);
+
+    imshow(name, out);
+}
+
 int main(int argc, const char* argv[])
 {
     if (argc < 3)
@@ -152,20 +163,90 @@ int main(int argc, const char* argv[])
     GpuMat d_frame0(frame0);
     GpuMat d_frame1(frame1);
 
-    GpuMat d_flowx, d_flowy;
+    GpuMat d_flowx(frame0.size(), CV_32FC1);
+    GpuMat d_flowy(frame0.size(), CV_32FC1);
+
+    BroxOpticalFlow brox(0.197, 50.0, 0.8, 10, 77, 10);
+    PyrLKOpticalFlow lk; lk.winSize = Size(7, 7);
+    FarnebackOpticalFlow farn;
     OpticalFlowDual_TVL1_GPU tvl1;
+    FastOpticalFlowBM fastBM;
 
-    const double start = getTickCount();
-    tvl1(d_frame0, d_frame1, d_flowx, d_flowy);
-    const double timeSec = (getTickCount() - start) / getTickFrequency();
-    cout << "Time : " << timeSec << " sec" << endl;
+    {
+        GpuMat d_frame0f;
+        GpuMat d_frame1f;
 
-    Mat flowx(d_flowx);
-    Mat flowy(d_flowy);
-    Mat out;
-    drawOpticalFlow(flowx, flowy, out);
+        d_frame0.convertTo(d_frame0f, CV_32F, 1.0 / 255.0);
+        d_frame1.convertTo(d_frame1f, CV_32F, 1.0 / 255.0);
+
+        const double start = getTickCount();
+
+        brox(d_frame0f, d_frame1f, d_flowx, d_flowy);
+
+        const double timeSec = (getTickCount() - start) / getTickFrequency();
+        cout << "Brox : " << timeSec << " sec" << endl;
+
+        showFlow("Brox", d_flowx, d_flowy);
+    }
+
+    {
+        const double start = getTickCount();
+
+        lk.dense(d_frame0, d_frame1, d_flowx, d_flowy);
+
+        const double timeSec = (getTickCount() - start) / getTickFrequency();
+        cout << "LK : " << timeSec << " sec" << endl;
+
+        showFlow("LK", d_flowx, d_flowy);
+    }
+
+    {
+        const double start = getTickCount();
+
+        farn(d_frame0, d_frame1, d_flowx, d_flowy);
+
+        const double timeSec = (getTickCount() - start) / getTickFrequency();
+        cout << "Farn : " << timeSec << " sec" << endl;
+
+        showFlow("Farn", d_flowx, d_flowy);
+    }
+
+    {
+        const double start = getTickCount();
+
+        tvl1(d_frame0, d_frame1, d_flowx, d_flowy);
+
+        const double timeSec = (getTickCount() - start) / getTickFrequency();
+        cout << "TVL1 : " << timeSec << " sec" << endl;
+
+        showFlow("TVL1", d_flowx, d_flowy);
+    }
+
+    {
+        const double start = getTickCount();
+
+        GpuMat buf;
+        calcOpticalFlowBM(d_frame0, d_frame1, Size(7, 7), Size(1, 1), Size(21, 21), false, d_flowx, d_flowy, buf);
+
+        const double timeSec = (getTickCount() - start) / getTickFrequency();
+        cout << "BM : " << timeSec << " sec" << endl;
+
+        showFlow("BM", d_flowx, d_flowy);
+    }
+
+    {
+        const double start = getTickCount();
+
+        fastBM(d_frame0, d_frame1, d_flowx, d_flowy);
+
+        const double timeSec = (getTickCount() - start) / getTickFrequency();
+        cout << "Fast BM : " << timeSec << " sec" << endl;
+
+        showFlow("Fast BM", d_flowx, d_flowy);
+    }
 
-    imshow("Flow", out);
+    imshow("Frame 0", frame0);
+    imshow("Frame 1", frame1);
     waitKey();
 
     return 0;