fixed bug in cv::Scharr and cv::Laplacian (ddepth < 0)

modules/imgproc/src/deriv.cpp

@@ -507,6 +507,8 @@ void cv::Scharr( const InputArray& _src, OutputArray _dst, int ddepth, int dx, i
                  double scale, double delta, int borderType )
 {
     Mat src = _src.getMat();
+    if (ddepth < 0)
+        ddepth = src.depth();
     _dst.create( src.size(), CV_MAKETYPE(ddepth, src.channels()) );
     Mat dst = _dst.getMat();
     
@@ -538,6 +540,8 @@ void cv::Laplacian( const InputArray& _src, OutputArray _dst, int ddepth, int ks
                     double scale, double delta, int borderType )
 {
     Mat src = _src.getMat();    
+    if (ddepth < 0)
+        ddepth = src.depth();
     _dst.create( src.size(), CV_MAKETYPE(ddepth, src.channels()) );
     Mat dst = _dst.getMat();