how to calculate the area size of each spot in the image of ROI (pixels) in Matlab

I have a spot pattern (similar to the picture of rice grains below). I want to calculate the area of each rice grain in the image ROI. But no relevant discussions were found

clc;close

I=imread('rice.png');

imshow(I);

height = 200;

width = 200;

roi = images.roi.Rectangle(gca,'Position',[10,10,width,height],'StripeColor','r');

Answer 1

[Image Analyst]

See my Image Segmentation Tutorial and adapt as needed:

Image Analyst's File Exchange

If you need to background correct your image, see my attached demo.

[chihyu]

Thank you very much. I try it