Counting Plotted Coordinates in image

I have a gray scale image given below:

I plot blue dot on certain coordinates given in 2xN matrix and get the following:

Now i convert the image into patches like below:

Now i want to count these blue dots in each patch as well as in image 2. How do i do that ?

Answer 1

[David J. Mack]

If you have your 2xN dot matrix dots which presumably contain the x (row 1) and y (row 2) coordinates, then N is the number of dots in the whole image and

ni = nnz(dots(1,:)>=xi & dots(1,:)<xi+wi) & dots(2,:)>=yi & dots(1,:)<yi+hi));

Gives you the number of dots in image patch i, which has its lower left corner at (xi,yi) and has a width x size of wi x hi.