Draw a circle and measure the white pixels area inside

Hello everyone, a binary image is obtained. The work is to draw concentric cirles in the image and calculate the area of the white pixels in each circle. The objective is to get a curve.

I attached an image as an example.

[Walter Roberson]

Construct a binary mask which is a circle of appropriate radius at appropriate center. Use .* to multiply the mask and the binary form of the image. nnz() then gives the white count.

[Hassan Khalil]

Thank you very much. It works. Not automatically for all the concentric radius but radius by radius. At each time, I change the radius value with the same center coordinates. The objective is done.

Answer 1

[Walter Roberson]

You can construct a distance-squared matrix once. Then you can

sum(bsxfun(@le, distance_squared_matrix(:), radius_row_vector.^2))

to get the counts.

[Hassan Khalil]

Come back from vacation to get a good idea proposed by you.

Thank you

Answer 2

[KSSV]

I = imread('image.png') ; 
I1 = rgb2gray(I) ; 
[y,x] = find(I1) ; 
length(x)