Add CV_Asserts for channels count

modules/photo/src/fast_nlmeans_denoising_invoker.hpp

@@ -106,6 +106,8 @@ FastNlMeansDenoisingInvoker<T>::FastNlMeansDenoisingInvoker(
     int search_window_size, 
     const double h) : src_(src), dst_(dst)
 {
+    CV_Assert(src.channels() <= 3);
+
     template_window_half_size_ = template_window_size / 2;
     search_window_half_size_ = search_window_size / 2;
     template_window_size_ = template_window_half_size_ * 2 + 1;

modules/photo/src/fast_nlmeans_multi_denoising_invoker.hpp

@@ -115,6 +115,9 @@ FastNlMeansMultiDenoisingInvoker<T>::FastNlMeansMultiDenoisingInvoker(
     int search_window_size, 
     const double h) : dst_(dst), extended_srcs_(srcImgs.size())
 {
+    CV_Assert(srcImgs.size() > 0);
+    CV_Assert(srcImgs[0].channels() <= 3);
+
     rows_ = srcImgs[0].rows;
     cols_ = srcImgs[0].cols;
     channels_count_ = srcImgs[0].channels();