Anchor cylinder (or circle) in subpixel coordinates of the rendered image in Blender

I am developing a model of the kind of a calibration target in Blender. The calibration target contains a set of circular markers. In order to test the accuracy of my c++ procedures, I need to know exact pixel positions of markers in the rendered images. I am new in Blender and I am just wondering if it is possible to anchor circle (or cylinder) center in exact pixel (subpixel even better) coordinates of the rendered image. Did anyone encountered a simi开发者_StackOverflow中文版lar problem? Thanks for your help.

You could render the image with 10x higher resolution, then downsample it by averaging 10x10 pixel blocks.