Added naive blockmatching algorithm (just to get acquainted with the code base,…

Added naive blockmatching algorithm (just to get acquainted with the code base, this algo shouldn't be considered seriously).
Also, added boilerplate for pcaflow.

modules/optflow/include/opencv2/optflow.hpp

@@ -191,6 +191,10 @@ CV_EXPORTS_W Ptr<DenseOpticalFlow> createOptFlow_Farneback();
 //! Additional interface to the SparseToDenseFlow algorithm - calcOpticalFlowSparseToDense()
 CV_EXPORTS_W Ptr<DenseOpticalFlow> createOptFlow_SparseToDense();
 
+CV_EXPORTS_W Ptr<DenseOpticalFlow> createOptFlow_BlockMatching();
+
+CV_EXPORTS_W Ptr<DenseOpticalFlow> createOptFlow_PCAFlow();
+
 //! @}
 
 } //optflow

modules/optflow/samples/optical_flow_evaluation.cpp

@@ -11,7 +11,7 @@ using namespace optflow;
 const String keys = "{help h usage ? |      | print this message   }"
         "{@image1        |      | image1               }"
         "{@image2        |      | image2               }"
-        "{@algorithm     |      | [farneback, simpleflow, tvl1, deepflow or sparsetodenseflow] }"
+        "{@algorithm     |      | [farneback, simpleflow, tvl1, deepflow, pcaflow, blockmatching or sparsetodenseflow] }"
         "{@groundtruth   |      | path to the .flo file  (optional), Middlebury format }"
         "{m measure      |endpoint| error measure - [endpoint or angular] }"
         "{r region       |all   | region to compute stats about [all, discontinuities, untextured] }"
@@ -252,6 +252,10 @@ int main( int argc, char** argv )
         algorithm = createOptFlow_DeepFlow();
     else if ( method == "sparsetodenseflow" )
         algorithm = createOptFlow_SparseToDense();
+    else if ( method == "blockmatching" )
+        algorithm = createOptFlow_BlockMatching();
+    else if ( method == "pcaflow" )
+        algorithm = createOptFlow_PCAFlow();
     else
     {
         printf("Wrong method!\n");

modules/optflow/src/block_matching.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.
+ //
+ //
+ //                           License Agreement
+ //                For Open Source Computer Vision Library
+ //
+ // Copyright (C) 2000-2008, Intel Corporation, all rights reserved.
+ // Copyright (C) 2009, Willow Garage Inc., 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 the copyright holders 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 "precomp.hpp"
+
+namespace cv
+{
+namespace optflow
+{
+
+class OpticalFlowBlockMatching : public DenseOpticalFlow
+{
+protected:
+  int windowSize;
+  int blockSize;
+
+  inline float submatrixAbsDiff( int x0, int y0, const Mat &I0, int x1, int y1, const Mat &I1 ) const;
+
+public:
+  OpticalFlowBlockMatching() : windowSize( 3 ), blockSize( 8 ){};
+
+  void calc( InputArray I0, InputArray I1, InputOutputArray flow );
+  void collectGarbage();
+};
+
+inline float OpticalFlowBlockMatching::submatrixAbsDiff( int x0, int y0, const Mat &I0, int x1, int y1,
+                                                         const Mat &I1 ) const
+{
+  float error = 0;
+  const Size size = I0.size();
+  for ( int i = -windowSize; i <= windowSize; ++i )
+  {
+    if ( i + y0 < 0 || i + y0 >= size.height || i + y1 < 0 || i + y1 >= size.height )
+    {
+      error += 1;
+      continue;
+    }
+    const Vec3f *I0X = I0.ptr<Vec3f>( i + y0 );
+    const Vec3f *I1X = I1.ptr<Vec3f>( i + y1 );
+    for ( int j = -windowSize; j <= windowSize; ++j )
+    {
+      if ( j + x0 < 0 || j + x0 >= size.width || j + x1 < 0 || j + x1 >= size.width )
+      {
+        error += 1;
+        continue;
+      }
+      const Vec3f diff = I0X[j + x0] - I1X[j + x1];
+      error += abs( diff[0] );
+      error += abs( diff[1] );
+      error += abs( diff[2] );
+    }
+  }
+  return error;
+}
+
+void OpticalFlowBlockMatching::calc( InputArray I0, InputArray I1, InputOutputArray flow_out )
+{
+  CV_Assert( I0.channels() == 3 );
+  CV_Assert( I1.channels() == 3 );
+  Size size = I0.size();
+  CV_Assert( size == I1.size() );
+
+  flow_out.create( size, CV_32FC2 );
+  Mat flow = flow_out.getMat();
+  Mat from = I0.getMat();
+  Mat to = I1.getMat();
+
+  from.convertTo( from, CV_32FC3, 1.0 / 255.0 );
+  to.convertTo( to, CV_32FC3, 1.0 / 255.0 );
+
+  const float distNormalize = blockSize * sqrt( 2 );
+
+  for ( int y0 = 0; y0 < size.height; ++y0 )
+  {
+    Vec2f *flowX = flow.ptr<Vec2f>( y0 );
+    const int yEnd = std::min( size.height - 1, y0 + blockSize );
+
+    for ( int x0 = 0; x0 < size.width; ++x0 )
+    {
+      float minDiff = 1e10;
+      Vec2f du( 0, 0 );
+      const int xEnd = std::min( size.width - 1, x0 + blockSize );
+      for ( int y1 = std::max( 0, y0 - blockSize ); y1 <= yEnd; ++y1 )
+        for ( int x1 = std::max( 0, x0 - blockSize ); x1 <= xEnd; ++x1 )
+        {
+          const float distance = sqrt( ( x0 - x1 ) * ( x0 - x1 ) + ( y0 - y1 ) * ( y0 - y1 ) ) / distNormalize;
+          const float kernel = 1.0 + 0.5 * distance;
+          const float diff = kernel * submatrixAbsDiff( x0, y0, from, x1, y1, to );
+          if ( diff < minDiff )
+          {
+            minDiff = diff;
+            du = Vec2f( ( x1 - x0 ), ( y1 - y0 ) );
+          }
+        }
+      flowX[x0] = du;
+    }
+  }
+}
+
+void OpticalFlowBlockMatching::collectGarbage() {}
+
+Ptr<DenseOpticalFlow> createOptFlow_BlockMatching() { return makePtr<OpticalFlowBlockMatching>(); }
+}
+}

modules/optflow/src/pcaflow.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.
+ //
+ //
+ //                           License Agreement
+ //                For Open Source Computer Vision Library
+ //
+ // Copyright (C) 2000-2008, Intel Corporation, all rights reserved.
+ // Copyright (C) 2009, Willow Garage Inc., 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 the copyright holders 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 "precomp.hpp"
+
+namespace cv
+{
+namespace optflow
+{
+
+class OpticalFlowPCAFlow : public DenseOpticalFlow
+{
+protected:
+  float sparseRate;
+
+public:
+  OpticalFlowPCAFlow() : sparseRate( 0.02 ){};
+
+  void calc( InputArray I0, InputArray I1, InputOutputArray flow );
+  void collectGarbage();
+
+private:
+  void findSparseFeatures( Mat &from, Mat &to, std::vector<Point2f> &features,
+                           std::vector<Point2f> &predictedFeatures );
+};
+
+void OpticalFlowPCAFlow::findSparseFeatures( Mat &from, Mat &to, std::vector<Point2f> &features,
+                                             std::vector<Point2f> &predictedFeatures )
+{
+  std::vector<uchar> predictedStatus;
+  std::vector<float> predictedError;
+  calcOpticalFlowPyrLK( from, to, features, predictedFeatures, predictedStatus, predictedError );
+
+  size_t j = 0;
+  for ( size_t i = 0; i < features.size(); ++i )
+  {
+    if ( predictedStatus[i] )
+    {
+      features[j] = features[i];
+      predictedFeatures[j] = predictedFeatures[i];
+      ++j;
+    }
+  }
+  features.resize( j );
+  predictedFeatures.resize( j );
+}
+
+void OpticalFlowPCAFlow::calc( InputArray I0, InputArray I1, InputOutputArray flow_out )
+{
+  Size size = I0.size();
+  CV_Assert( size == I1.size() );
+  CV_Assert( sparseRate > 0 && sparseRate < 0.1 );
+
+  Mat from, to;
+  if ( I0.channels() == 3 )
+  {
+    cvtColor( I0, from, COLOR_BGR2GRAY );
+    from.convertTo( from, CV_8U );
+  }
+  else
+  {
+    I0.getMat().convertTo( from, CV_8U );
+  }
+  if ( I1.channels() == 3 )
+  {
+    cvtColor( I1, to, COLOR_BGR2GRAY );
+    to.convertTo( to, CV_8U );
+  }
+  else
+  {
+    I1.getMat().convertTo( to, CV_8U );
+  }
+
+  CV_Assert( from.channels() == 1 );
+  CV_Assert( to.channels() == 1 );
+
+  std::vector<Point2f> features, predictedFeatures;
+  const unsigned maxFeatures = size.area() * sparseRate;
+  goodFeaturesToTrack( from, features, maxFeatures, 0.005, 3 );
+
+  // Add points along the grid if not enough features
+  {
+    const unsigned missingPoints = maxFeatures - features.size();
+    const unsigned blockSize = sqrt( (float)size.area() / missingPoints );
+    for ( int x = blockSize / 2; x < size.width; x += blockSize )
+      for ( int y = blockSize / 2; y < size.height; y += blockSize )
+        features.push_back( Point2f( x, y ) );
+  }
+
+  findSparseFeatures( from, to, features, predictedFeatures );
+
+  // TODO: Remove occlusions
+
+  flow_out.create( size, CV_32FC2 );
+  Mat flow = flow_out.getMat();
+  for ( size_t i = 0; i < features.size(); ++i )
+  {
+    flow.at<Point2f>( features[i].y, features[i].x ) = predictedFeatures[i] - features[i];
+  }
+
+  from.convertTo( from, CV_32F );
+  to.convertTo( to, CV_32F );
+}
+
+void OpticalFlowPCAFlow::collectGarbage() {}
+
+Ptr<DenseOpticalFlow> createOptFlow_PCAFlow() { return makePtr<OpticalFlowPCAFlow>(); }
+}
+}