How to determine the area of individual white picture elements?

Hello, I would like to evaluate a binary image with a black background and white circles or areas. The white areas resemble circles but not all of them are perfectly round.

I have the code so far that I have a binary image and can also display the radii approximately.

Now I am interested in the exact area of the white surfaces.

How can I display the individual white areas in pixels? And how do I convert the pixels into mm^2?

Answer 1

[DGM]

You can use regionprops to find the areas of all objects in a binary image. The result is an area measured in pixels. To convert that to some physical unit, your images need some sort of calibration information that relates image geometry to physical object geometry. For example, if you know that 1mm = 10px, and that relationship is sufficiently uniform throughout the image, then you can just divide your calculated areas by 10^2.