If you have blue marked points that are clearly (means that they are not a half pixel wide) visible, then you could actually do the following
- Take the blue channel from your RGB image
- Normalize the blue colour channel for the other colours
- Look for local maxima (using some threshold region) in that image, it will be points with high blue components
- Create a binary mask for those maxima found
- Assign contours to those regions
- Calculate center points for those regions
- Save the center points to a txt file or something else that is desired.
Cheerz!
