Question

I’m profiling the code that I have developed, and I see a bottleneck in my code when I use cvSet2D.
Is there some alternative to cvSet2D more efficient?

How can I write that pixels?

Answer 1

I recommend you to use the C++ functions and not the old C style functions.

The most efficient way to write to pixels is the following.

   cv::Mat frame;

   // load your img to your Mat

   uchar* p = frame.ptr(row); // returns a row pointer
   p[column] = x; // accesses value in the given column

One thing to note is that you might have more columns than you have pixel columns, e.g. on a 3 channel image you have 3 times the number of actual pixel columns you can access.

For more information on different ways to iterate over pixels, check this tutorial.