How to crop only selected part of an image automatically?

I have some image, from this image I need to identify only some portion that's mean segmentation. After identification, I need to crop this portion automatically. I found some code for automatically cropping but don't work exactly what I want! In my dataset images are different and for that reasons, segmented images also different. For example, a pre-processed image is first one and I need to detect the image in that way, an example is the second one.

Now I want to crop the right image automatically only segmented area.

In my code, it cropped incorrectly different region :(.

In my dataset images is different one from another!

My code is given below:

close all;

I=imread('CL_2_2.jpg');
figure, imshow(I);
I=rgb2gray(I);
BW=I>100;
figure,imshow(BW);
labeledImage = bwlabel(BW);
measurements = regionprops(labeledImage, 'BoundingBox', 'Area');
for k = 1 : length(measurements)
thisBB = measurements(k).BoundingBox;
I2=imcrop(I,[thisBB(1),thisBB(2),thisBB(3),thisBB(4)]);
[rows cols depth]=size(I2);
if rows*cols>200
    I2=imresize(I2,[28 28]);
    figure,imshow(I2);
  end
end

Answer 1

[Majid Farzaneh]

Hi It works. But you have used imresize and have changed the segments. Also your threshold for segments sizes (200) may be large. For showing smaller objects you should take it smaller. I tried this and it worked:

close all;
I=imread('CL_2_2.jpg');
figure, imshow(I);
I=rgb2gray(I);
BW=I>100;
figure,imshow(BW);
labeledImage = bwlabel(BW);
measurements = regionprops(labeledImage, 'BoundingBox', 'Area');
for k = 1 : length(measurements)
thisBB = measurements(k).BoundingBox;
I2=imcrop(I,[thisBB(1),thisBB(2),thisBB(3),thisBB(4)]);
[rows cols depth]=size(I2);
if rows*cols>100
    %%%%%%%I2=imresize(I2,[28 28]);
    figure,imshow(I2);
end
end

[Akib Rahman]

Thanks, Majid for your answer. But when I run your code it gives me one wrong figure and that was the lower right number portion. but it is not in my region of interest. Another questions is, if I want to save this cropping figure than what should I write in my code. Thanks in advanced :)

[Majid Farzaneh]

You're welcome. Your algorithm is not clever enough to recognize difference between ROI and the numbers. You can try some other threshold (e.g. 150) or develop your code to understand the numbers. For saving figures check this .

Answer 2

[Jyoti Verma]

Croping an Image,

%Read and Display an Image,

I=imread('rec.jpg');

%rgb conversion,

J=rgb2gray(I);

subplot(221);imshow(I);title('RGB image Figure')

% Crop Image Using Crop Image Interactive Tool

[K, rect] = imcrop(J);

subplot(222);imshow(J);title('Gray image Figure')

% cropped image in matlab

I2 = imcrop(J,[12.5 8.5 411 99]);

subplot(223);imshow(I2);title('Cropped image Figure')

% BINARY CONVERSION

I3=im2bw(I2);

subplot(224);imshow(I3);title('Binary image Figure')