Minor fixes

modules/optflow/include/opencv2/optflow/pcaflow.hpp

@@ -96,7 +96,7 @@ protected:
 
 public:
   OpticalFlowPCAFlow( Ptr<const PCAPrior> _prior = Ptr<const PCAPrior>(), const Size _basisSize = Size( 18, 14 ),
-                      float _sparseRate = 0.02, float _retainedCornersFraction = 0.7,
+                      float _sparseRate = 0.024, float _retainedCornersFraction = 0.2,
                       float _occlusionsThreshold = 0.0003, float _dampingFactor = 0.00002 );
 
   void calc( InputArray I0, InputArray I1, InputOutputArray flow );

modules/optflow/src/learn_prior.py

@@ -16,7 +16,7 @@ Gamma should be selected experimentally.''')
 argparser.add_argument('-f',
                        '--files',
                        nargs='+',
-                       help='List of optical flow .flo files for learning',
+                       help='List of optical flow .flo files for learning. You can pass a directory here and it will be scanned recursively for .flo files.',
                        required=True)
 argparser.add_argument('-o',
                        '--output',

modules/optflow/src/pcaflow.cpp

@@ -117,9 +117,8 @@ static inline void symOrtho( double a, double b, double &c, double &s, double &r
 static void solveLSQR( const Mat &A, const Mat &b, OutputArray xOut, const double damp = 0.0,
                        const unsigned iter_lim = 10 )
 {
-  int m = A.size().height;
-  int n = A.size().width;
-  CV_Assert( m == b.size().height );
+  const int n = A.size().width;
+  CV_Assert( A.size().height == b.size().height );
   CV_Assert( A.type() == CV_32F );
   CV_Assert( b.type() == CV_32F );
   xOut.create( n, 1, CV_32F );
@@ -164,7 +163,7 @@ static void solveLSQR( const Mat &A, const Mat &b, OutputArray xOut, const doubl
       v += AT * u;
       alfa = cv::norm( v, NORM_L2 );
       if ( alfa > 0 )
-        v = ( 1 / alfa ) * v;
+        v *= 1 / alfa;
     }
 
     double rhobar1 = sqrt( rhobar * rhobar + damp * damp );