Fixed static analyzer warnings in DISOpticalFlow

modules/video/src/dis_flow.cpp

@@ -226,9 +226,11 @@ DISOpticalFlowImpl::DISOpticalFlowImpl()
     border_size = 16;
     use_mean_normalization = true;
     use_spatial_propagation = true;
+    coarsest_scale = 10;
 
     /* Use separate variational refinement instances for different scales to avoid repeated memory allocation: */
     int max_possible_scales = 10;
+    ws = hs = w = h = 0;
     for (int i = 0; i < max_possible_scales; i++)
         variational_refinement_processors.push_back(VariationalRefinement::create());
 }
@@ -1035,6 +1037,7 @@ void DISOpticalFlowImpl::Densification_ParBody::operator()(const Range &range) c
                     sum_Uy += coef * Sy_ptr[is * dis->ws + js];
                     sum_coef += coef;
                 }
+            CV_DbgAssert(sum_coef != 0);
             Ux_ptr[i * dis->w + j] = sum_Ux / sum_coef;
             Uy_ptr[i * dis->w + j] = sum_Uy / sum_coef;
         }

modules/video/src/variational_refinement.cpp

@@ -93,6 +93,7 @@ class VariationalRefinementImpl CV_FINAL : public VariationalRefinement
         int red_even_len, red_odd_len;
         int black_even_len, black_odd_len;
 
+        RedBlackBuffer();
         void create(Size s);
         void release();
     };
@@ -366,6 +367,10 @@ void VariationalRefinementImpl::updateRepeatedBorders(RedBlackBuffer &dst)
     }
 }
 
+VariationalRefinementImpl::RedBlackBuffer::RedBlackBuffer()
+{
+    release();
+}
 void VariationalRefinementImpl::RedBlackBuffer::create(Size s)
 {
     /* Allocate enough memory to include borders */
@@ -386,6 +391,7 @@ void VariationalRefinementImpl::RedBlackBuffer::release()
 {
     red.release();
     black.release();
+    red_even_len = red_odd_len = black_even_len = black_odd_len = 0;
 }
 
 VariationalRefinementImpl::ParallelOp_ParBody::ParallelOp_ParBody(VariationalRefinementImpl &_var, vector<Op> _ops,