How to find the coordinates of the white square ?

Answer 1

[Matt J]

Some simple morphological operations are all you need.

A=imbinarize((imread('image.jpeg')));
 
 A=bwareafilt(  imopen(A,strel('disk',5))   ,1);
 
 [I,J] = find(A);  %The desired coordinates??
 
 imshow(A)

[Alaa Abusbeih]

How to find the coordinates in x-axis and y-axis of the white square

[Matt J]

Did you figure it out? I assume so, since you accepted the answer.

[Alaa Abusbeih]

what the value of A,I and J means ?

[Matt J]

A is the image, as displayed above, with everything but the square removed. I and J are the matrix coordinates of the non-zero pixels of A, see FIND.