fix vs2010 build error

modules/optflow/src/dis_flow.cpp

@@ -1066,7 +1066,7 @@ void DISOpticalFlowImpl::calc(InputArray I0, InputArray I1, InputOutputArray flo
     Mat uxy[] = {Ux[finest_scale], Uy[finest_scale]};
     merge(uxy, 2, U);
     resize(U, flowMat, flowMat.size());
-    flowMat *= pow(2, finest_scale);
+    flowMat *= 1 << finest_scale;
 }
 
 void DISOpticalFlowImpl::collectGarbage()

modules/optflow/src/pcaflow.cpp

@@ -226,7 +226,7 @@ void reduceToFlow( const Mat &w1, const Mat &w2, Mat &flow, const Size &basisSiz
   Mat flowX( size, CV_32F, 0.0f );
   Mat flowY( size, CV_32F, 0.0f );
 
-  const float mult = sqrt( size.area() ) * 0.5;
+  const float mult = sqrt( static_cast<float>(size.area()) ) * 0.5;
 
   for ( int i = 0; i < basisSize.width; ++i )
     for ( int j = 0; j < basisSize.height; ++j )
@@ -296,7 +296,7 @@ void OpticalFlowPCAFlow::removeOcclusions( UMat &from, UMat &to, std::vector<Poi
   calcOpticalFlowPyrLK( to, from, predictedFeatures, backwardFeatures, predictedStatus, predictedError );
 
   size_t j = 0;
-  const float threshold = occlusionsThreshold * sqrt( from.size().area() );
+  const float threshold = occlusionsThreshold * sqrt( static_cast<float>(from.size().area()) );
   for ( size_t i = 0; i < predictedFeatures.size(); ++i )
   {
     if ( predictedStatus[i] )

modules/xphoto/src/learning_based_color_balance.cpp

@@ -547,7 +547,7 @@ Vec2f LearningBasedWBImpl::predictIlluminant(vector<Vec2f> features)
     int local_model_size = num_features * feature_model_size;
     int feature_model_size_leaf = 2 * num_tree_nodes;
     int local_model_size_leaf = num_features * feature_model_size_leaf;
-    tree_depth = (int)round(log(num_tree_nodes) / log(2));
+    tree_depth = cvRound( (log(static_cast<float>(num_tree_nodes)) / log(2.0f)) );
 
     vector<float> consensus_r, consensus_g;
     vector<float> all_r, all_g;