added methods estimateRecopmmendedParams for StereoBP and StereoCSBP

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

@@ -415,6 +415,8 @@ namespace cv
             enum { DEFAULT_ITERS  = 5  };
             enum { DEFAULT_LEVELS = 5  };
 
+            static void estimateRecopmmendedParams( int width, int height, int & ndisp, int & iters, int & levels);
+
             //! the default constructor
             explicit StereoBeliefPropagation(int ndisp  = DEFAULT_NDISP,
                                              int iters  = DEFAULT_ITERS,
@@ -471,6 +473,8 @@ namespace cv
             enum { DEFAULT_LEVELS   = 4   };
             enum { DEFAULT_NR_PLANE = 4   };
 
+            static void estimateRecopmmendedParams( int width, int height, int & ndisp, int & iters, int & levels, int & nr_plane);
+
             //! the default constructor
             explicit StereoConstantSpaceBP(int ndisp    = DEFAULT_NDISP,
                                            int iters    = DEFAULT_ITERS,

modules/gpu/src/beliefpropagation_gpu.cpp

@@ -77,6 +77,19 @@ namespace
     const float DEFAULT_DISC_SINGLE_JUMP = 1.0f;
 }
 
+
+void cv::gpu::StereoBeliefPropagation::estimateRecopmmendedParams( int width, int height, int & ndisp, int & iters, int & levels)
+{
+    ndisp = width / 4;
+    if (ndisp & 1 != 0) ndisp++;
+
+    int mm =::max(width, height);
+    iters = mm / 100 + 2;
+
+    levels = (int)(log(mm) + 1) * 4 / 5;
+    if (levels == 0) levels++;
+}
+
 cv::gpu::StereoBeliefPropagation::StereoBeliefPropagation(int ndisp_, int iters_, int levels_, int msg_type_)
     : ndisp(ndisp_), iters(iters_), levels(levels_),
       max_data_term(DEFAULT_MAX_DATA_TERM), data_weight(DEFAULT_DATA_WEIGHT),

modules/gpu/src/constantspacebp_gpu.cpp

@@ -105,6 +105,20 @@ namespace
     const float DEFAULT_DISC_SINGLE_JUMP = 10.0f;
 }
 
+void cv::gpu::StereoConstantSpaceBP::estimateRecopmmendedParams( int width, int height, int & ndisp, int & iters, int & levels, int &nr_plane)
+{
+    ndisp = (int) ((float) width / 3.14f);
+    if (ndisp & 1 != 0) ndisp++;
+
+    int mm = ::max(width, height);
+    iters = mm / 100 + ((mm > 1200)? - 4 : 4);
+
+    levels = (int)log(mm) * 2 / 3;
+    if (levels == 0) levels++;
+
+    nr_plane = (int) ((float) ndisp / pow(2.0, levels + 1));
+}
+
 cv::gpu::StereoConstantSpaceBP::StereoConstantSpaceBP(int ndisp_, int iters_, int levels_, int nr_plane_,
                                                       int msg_type_)