MATLAB: How to crop an image inside a boundary

image croppingMATLAB

I have an image from which I want to crop a certain portion of it. I drew the boundary at first. Below is the code:
img = imread('Intensity1.jpg');
figure, imshow(img);
% getting a segment 
h=drawfreehand();
position = wait(h);
region=uint8(roipoly(img,position(:,1),position(:,2)));
region=region.*img;
figure,imshow(region); title('Segmented Region');
% use bwperim rather than bwboundaries to get an Image of boundary.
boundImg = uint8(bwperim(rgb2gray(region),4));
boundImg(boundImg ~=0) = max(img(:));
figure, imshow(img + boundImg)
% save image without loosing information..
imwrite(img + boundImg, 'writeImg.jpg');
% check 
read = imread('writeImg.jpg');
figure, imshow(read)
isequal(read, img + boundImg)
The image is below:
fh.jpg
I want to crop the portion of the image specified by the boundary above. I tried the following line of code but there is no change in the result.
imcrop('Intensity1.jpg');
Any suggestions would be very much appreciated. Thank you.

Best Answer

region=uint8(roipoly(img,position(:,1),position(:,2)));
After getting the mask of the selected region from the above line in your code, you can use regionprops to obtain a rectangular box around the mask and then use imcrop to crop the image.
stats = regionprops(region, 'BoundingBox');
crop_region = stats.BoundingBox; % contains [top_left_x top_left_y width height]
cropped_img = imcrop(img, crop_region);
For more information on how to use regionprops and imcrop, refer to the following links:
https://www.mathworks.com/help/images/ref/regionprops.html
https://www.mathworks.com/help/images/ref/imcrop.html
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