How to convert BRISKPoints into binary mask?

Hi, I have BRISKPoints object and I need to convert BRISKPoints.Location data into binary mask. For example, if:

BRISKPoints.Location = [136.8434  114.7649]

then x = 136.8434, y = 114.7649 (some point in x,y coordinates). But originally, this point was found in uint8(200x200) picture, and now I need to build a binary mask of same size as original image, where in x = 136.8434, y = 114.7649 point will appear 1 (others 0).

How to remap these float coordinates into indexes within mask?

Or may be I need just a type conversion, will it work?

Thank you