OCL implementation of DIS optical flow

This patch adds ocl kernels to accelerate Dense Inverse Search
based optical flow algorithm, it acclerates 3 parts in the algorithm,
including 1) Structure tensor elements compute, 2) Patch inverse search,
3) Densification compute.

Perf and accuracy test are also added. The perf test shows it is 30%
faster than the current implementation.
Signed-off-by: Li Peng <peng.li@intel.com>

modules/optflow/perf/opencl/perf_dis_optflow.cpp

+/*
+ *  By downloading, copying, installing or using the software you agree to this license.
+ *  If you do not agree to this license, do not download, install,
+ *  copy or use the software.
+ *
+ *
+ *  License Agreement
+ *  For Open Source Computer Vision Library
+ *  (3 - clause BSD License)
+ *
+ *  Redistribution and use in source and binary forms, with or without modification,
+ *  are permitted provided that the following conditions are met :
+ *
+ *  * Redistributions of source code must retain the above copyright notice,
+ *  this list of conditions and the following disclaimer.
+ *
+ *  * Redistributions in binary form must reproduce the above copyright notice,
+ *  this list of conditions and the following disclaimer in the documentation
+ *  and / or other materials provided with the distribution.
+ *
+ *  * Neither the names of the copyright holders nor the names of the contributors
+ *  may be used to endorse or promote products derived from this software
+ *  without specific prior written permission.
+ *
+ *  This software is provided by the copyright holders and contributors "as is" and
+ *  any express or implied warranties, including, but not limited to, the implied
+ *  warranties of merchantability and fitness for a particular purpose are disclaimed.
+ *  In no event shall copyright holders or contributors be liable for any direct,
+ *  indirect, incidental, special, exemplary, or consequential damages
+ *  (including, but not limited to, procurement of substitute goods or services;
+ *  loss of use, data, or profits; or business interruption) however caused
+ *  and on any theory of liability, whether in contract, strict liability,
+ *  or tort(including negligence or otherwise) arising in any way out of
+ *  the use of this software, even if advised of the possibility of such damage.
+ */
+
+#include "../perf_precomp.hpp"
+#include "opencv2/ts/ocl_perf.hpp"
+
+using std::tr1::tuple;
+using std::tr1::get;
+using namespace perf;
+using namespace testing;
+using namespace cv;
+using namespace cv::optflow;
+
+#ifdef HAVE_OPENCL
+
+namespace cvtest {
+namespace ocl {
+
+void MakeArtificialExample(UMat &dst_frame1, UMat &dst_frame2);
+
+typedef tuple<String, Size> DISParams;
+typedef TestBaseWithParam<DISParams> DenseOpticalFlow_DIS;
+
+OCL_PERF_TEST_P(DenseOpticalFlow_DIS, perf,
+                Combine(Values("PRESET_ULTRAFAST", "PRESET_FAST", "PRESET_MEDIUM"), Values(szVGA, sz720p, sz1080p)))
+{
+    DISParams params = GetParam();
+
+    // use strings to print preset names in the perf test results:
+    String preset_string = get<0>(params);
+    int preset = DISOpticalFlow::PRESET_FAST;
+    if (preset_string == "PRESET_ULTRAFAST")
+        preset = DISOpticalFlow::PRESET_ULTRAFAST;
+    else if (preset_string == "PRESET_FAST")
+        preset = DISOpticalFlow::PRESET_FAST;
+    else if (preset_string == "PRESET_MEDIUM")
+        preset = DISOpticalFlow::PRESET_MEDIUM;
+    Size sz = get<1>(params);
+
+    UMat frame1(sz, CV_8U);
+    UMat frame2(sz, CV_8U);
+    UMat flow;
+
+    MakeArtificialExample(frame1, frame2);
+
+    Ptr<DenseOpticalFlow> algo = createOptFlow_DIS(preset);
+
+    OCL_TEST_CYCLE_N(10)
+    {
+        algo->calc(frame1, frame2, flow);
+    }
+
+    SANITY_CHECK_NOTHING();
+}
+
+void MakeArtificialExample(UMat &dst_frame1, UMat &dst_frame2)
+{
+    int src_scale = 2;
+    int OF_scale = 6;
+    double sigma = dst_frame1.cols / 300;
+
+    UMat tmp(Size(dst_frame1.cols / (int)pow(2, src_scale), dst_frame1.rows / (int)pow(2, src_scale)), CV_8U);
+    randu(tmp, 0, 255);
+    resize(tmp, dst_frame1, dst_frame1.size(), 0.0, 0.0, INTER_LINEAR);
+    resize(tmp, dst_frame2, dst_frame2.size(), 0.0, 0.0, INTER_LINEAR);
+
+    Mat displacement_field(Size(dst_frame1.cols / (int)pow(2, OF_scale), dst_frame1.rows / (int)pow(2, OF_scale)),
+                           CV_32FC2);
+    randn(displacement_field, 0.0, sigma);
+    resize(displacement_field, displacement_field, dst_frame2.size(), 0.0, 0.0, INTER_CUBIC);
+    for (int i = 0; i < displacement_field.rows; i++)
+        for (int j = 0; j < displacement_field.cols; j++)
+            displacement_field.at<Vec2f>(i, j) += Vec2f((float)j, (float)i);
+
+    remap(dst_frame2, dst_frame2, displacement_field, Mat(), INTER_LINEAR, BORDER_REPLICATE);
+}
+
+} } // namespace cvtest::ocl
+
+#endif // HAVE_OPENCL

modules/optflow/src/precomp.hpp

@@ -45,6 +45,8 @@ the use of this software, even if advised of the possibility of such damage.
 #include <opencv2/optflow.hpp>
 #include <opencv2/video.hpp>
 #include <opencv2/imgproc.hpp>
+#include "opencv2/core/utility.hpp"
+#include "opencv2/core/private.hpp"
 #include "opencv2/core/ocl.hpp"
 
 #include <algorithm>

modules/optflow/test/ocl/test_dis.cpp

+/*M///////////////////////////////////////////////////////////////////////////////////////
+//
+//  IMPORTANT: READ BEFORE DOWNLOADING, COPYING, INSTALLING OR USING.
+//
+//  By downloading, copying, installing or using the software you agree to this license.
+//  If you do not agree to this license, do not download, install,
+//  copy or use the software.
+//
+//
+//                        Intel License Agreement
+//                For Open Source Computer Vision Library
+//
+// Copyright (C) 2000, Intel Corporation, all rights reserved.
+// Third party copyrights are property of their respective owners.
+//
+// Redistribution and use in source and binary forms, with or without modification,
+// are permitted provided that the following conditions are met:
+//
+//   * Redistribution's of source code must retain the above copyright notice,
+//     this list of conditions and the following disclaimer.
+//
+//   * Redistribution's in binary form must reproduce the above copyright notice,
+//     this list of conditions and the following disclaimer in the documentation
+//     and/or other materials provided with the distribution.
+//
+//   * The name of Intel Corporation may not be used to endorse or promote products
+//     derived from this software without specific prior written permission.
+//
+// This software is provided by the copyright holders and contributors "as is" and
+// any express or implied warranties, including, but not limited to, the implied
+// warranties of merchantability and fitness for a particular purpose are disclaimed.
+// In no event shall the Intel Corporation or contributors be liable for any direct,
+// indirect, incidental, special, exemplary, or consequential damages
+// (including, but not limited to, procurement of substitute goods or services;
+// loss of use, data, or profits; or business interruption) however caused
+// and on any theory of liability, whether in contract, strict liability,
+// or tort (including negligence or otherwise) arising in any way out of
+// the use of this software, even if advised of the possibility of such damage.
+//
+//M*/
+
+#include "../test_precomp.hpp"
+#include "opencv2/ts/ocl_test.hpp"
+
+#ifdef HAVE_OPENCL
+
+using namespace cv;
+using namespace optflow;
+
+namespace cvtest {
+namespace ocl {
+
+PARAM_TEST_CASE(OCL_DenseOpticalFlow_DIS, int)
+{
+    int preset;
+
+    virtual void SetUp()
+    {
+        preset = GET_PARAM(0);
+    }
+};
+
+OCL_TEST_P(OCL_DenseOpticalFlow_DIS, Mat)
+{
+    Mat frame1, frame2, GT;
+
+    frame1 = imread(TS::ptr()->get_data_path() + "optflow/RubberWhale1.png");
+    frame2 = imread(TS::ptr()->get_data_path() + "optflow/RubberWhale2.png");
+
+    CV_Assert(!frame1.empty() && !frame2.empty());
+
+    cvtColor(frame1, frame1, COLOR_BGR2GRAY);
+    cvtColor(frame2, frame2, COLOR_BGR2GRAY);
+
+    Ptr<DenseOpticalFlow> algo;
+
+    // iterate over presets:
+    for (int i = 0; i < test_loop_times; i++)
+    {
+        Mat flow;
+        UMat ocl_flow;
+
+        algo = createOptFlow_DIS(preset);
+        OCL_OFF(algo->calc(frame1, frame2, flow));
+        OCL_ON(algo->calc(frame1, frame2, ocl_flow));
+        ASSERT_EQ(flow.rows, ocl_flow.rows);
+        ASSERT_EQ(flow.cols, ocl_flow.cols);
+
+        EXPECT_MAT_SIMILAR(flow, ocl_flow, 6e-3);
+    }
+}
+
+OCL_INSTANTIATE_TEST_CASE_P(Contrib, OCL_DenseOpticalFlow_DIS,
+                            Values(DISOpticalFlow::PRESET_ULTRAFAST,
+                                   DISOpticalFlow::PRESET_FAST,
+                                   DISOpticalFlow::PRESET_MEDIUM));
+
+} } // namespace cvtest::ocl
+
+#endif // HAVE_OPENCL