System Information

OpenCV version: 4.10.0
Operating System / Platform: All
Compiler & compiler version: All

Detailed description

The documentation for fastNlMeansDenoisingMulti states that it should support 16 bit values.
The implementation however, enforces 8 bit values even though the underlying code supports 16 bit.

A fix is available in my branch

Steps to reproduce

1. Run fastNlMeansDenoisingMulti with a 16 bit image.
2. Get error

Issue submission checklist

• I report the issue, it's not a question
• I checked the problem with documentation, FAQ, open issues, forum.opencv.org, Stack Overflow, etc and have not found any solution
• I updated to the latest OpenCV version and the issue is still there
• There is reproducer code and related data files (videos, images, onnx, etc)