Finding rectangular shape in binary image

Hello, I hope all is well with you in current pendemic problem.

I have an issue in processing the attahced images.

I tried to find retangular shape and crop the image but it was failed.

Below is the code I tried.

im = imread('0.3616.jpg')
im = rgb2gray(im);

figure
imshow(im);
BW = im2bw(im, 0.5);

binaryImage = BW;
[rows, columns] = find(binaryImage);
topRow = min(rows);
bottomRow = max(rows);
leftColumn = min(columns);
rightColumn = max(columns);
croppedImage = binaryImage(topRow:bottomRow, leftColumn:rightColumn);
figure 
imshow(croppedImage)

Could you help me with this issue?

Thank you!

Wooju

Answer 1

[Abhisek Pradhan]

I was able to reproduce the error. And the reason is quite simple. As you are using min and max to get the boundaries after using find, it is causing it store the position of first white dot in your image ( from all 4 side ).

Refer the following blog as a reference to Image Segmentation.

https://in.mathworks.com/matlabcentral/fileexchange/25157-image-segmentation-tutorial