Crop the irrelevant part of the Image

I am new to Matlab. I want to crop the highlighted part of the gray image and remove the rest part. How to do that, kindly explain as well. Thanks.

[Zaheer Abbas]

Somebody help please!

[Zaheer Abbas]

One last help please!

[Image Analyst]

You have not attached the original image. Not the cropped one, and not the one with the red box on it, but the original image. So, did you even try stdfilt()?

Answer 1

[Image Analyst]

If you know the bounding rows and columns, you can do indexing

croppedImage = rgbImage(row1:row2, col1:col2, :);

or use imcrop():

croppedImage = imcrop(rgbImage, [leftCol, topRow, (rightCol-leftCol+1), (bottomRow-topRow+1)]);

[Zaheer Abbas]

Thanks for the prompt reply, ImageAnalyst. I am still perplexed, can you show me an example of the implementation using this image?

[KSSV]

Let I be your image of size m,n,3.

r1=round(m/2); Icropped=I(1:r1,:,:);

[Image Analyst]

I gave you the implementation. If you need it in a full demo where I read in and display both images, see attached test.m below the image. It's longer because of that but essentially I'm just using the line:

croppedImage = rgbImage(row1:row2, col1:col2, :);

[Zaheer Abbas]

Thanks. You're great. One last question! In your code, you hard coded the values of rows and columns. Is there any way that rows and columns values can be determined dynamically (not hard coded). This is one sample image, there can be other images with different dimensions.

[Image Analyst]

Yes, but that was not the original question so I didn't answer that. You could use stdfilt() and threshold and find the bounding box. Search for braille here - I know I've done code for it before.

[Zaheer Abbas]

Sir, I tried to find the code, but couldn't find it. If you please help with the code (crop through bounding box). Really sorry, but I am really stuck in this. I have very little time. Thanks in Advance

Answer 2

[KSSV]

doc imcrop

When propted, draw a rectangle in your interested area.

I = imread('your image') ;   % Read image
imshow(I) ;
I1 = imcrop(I) ;  % crop the image
imshow(I1)
imwrite(I1,'croppedimage.jpg');   % save the image

[Zaheer Abbas]

I want to crop the highlighted part of the image that is inside the red box. imcrop() needs parameters for cropping the specific area. I guess, I need to know the parameters.

[KSSV]

You can input parameters or you can drag a rectangle on your required area. Run the above code, when image opens draw/ drag a rectangle. Your highlighted image will be saved on the name croppedimage.jpg

[Zaheer Abbas]

I don't want to draw a rectangle by myself. It should be auto cropped. So, I need to find those parameters on which basis I can crop the image.

[KSSV]

How about picking up half of the matrix after imread?

[Zaheer Abbas]

Thanks a lot sir! :) It helped me..

Answer 3

[Image Analyst]

Zaheer, I'm sure by now you've tried to take my suggestion and use stdfilt() to automatically get the bounding box. You can look at how I did it and compare it to your own.