MATLAB: How to select and crop a particular region from the image

Question

After some filtering, I manage to get this image,

My question is, how do you select and hopefully crop the region of interest? So I can get something like this.

Many thanks,

Answer 1

If you have the Image Processing Toolbox, you can use the function imrect() to select a rectangular area from your image. For example:

figure;
imshow(img);
h_rect = imrect();
% Rectangle position is given as [xmin, ymin, width, height]
pos_rect = h_rect.getPosition();
% Round off so the coordinates can be used as indices
pos_rect = round(pos_rect);
% Select part of the image
img_cropped = img(pos_rect(2) + (0:pos_rect(4)), pos_rect(1) + (0:pos_rect(3)));