Crop part of an image

Hi there.

i've an image : (120 * 160 px)

I want to crop part of that image where number is.

Finally result must be : (22 * 39 px)

Thank you for your help.

Answer 1

[Jan]

You did not explain the type of the image variable. It might be a gray-scale image of type UINT8. Row a 3D array of an RGB image the procedure must be modified.

[row, col] = find(img);
cropped    = img(min(col):max(col), min(row):max(row));

Note that the image might be transposed when it is displayed, so perhaps you have to swap row and col.

[Hamed]

When i tried :

 img = imread('f:\en\2.jpg');
 img = rgb2gray(img);
 [row, col] = find(img);

and then this :

   cropped = img(min(col):max(col), min(row):max(row));

I get error "Index exceeds matrix dimensions."

When swap row and col :

[col, row] = find(img);

Does't get any errors but 'cropped' variable does't crop that image!

[Hamed]

Any body ?

[Iman Ansari]

I=imread('136626633118722_2.jpg');
img=rgb2gray(I);
[col, row] = find(img<250);
cropped = I(min(col):max(col), min(row):max(row));
imshow(cropped,'InitialMagnification','fit')

[Ehsan R]

hi

i want to do the same thing for binary images

thanks a lot

[Image Analyst]

Jan's code works for binary images. An alternate method would be to use regionprops() to get the bounding box, then use imcrop().

[Ahmed Fasih]

Flipped row & col.

>> z = blkdiag(zeros(1,3),[1 2; 3 0], zeros(3,1))
z =
     0     0     0     0     0     0
     0     0     0     1     2     0
     0     0     0     3     0     0
     0     0     0     0     0     0
     0     0     0     0     0     0
     0     0     0     0     0     0
>> [row, col]=find(z)
row =
     2
     3
     2
col =
     4
     4
     5
>> z(min(row):max(row), min(col):max(col))
ans =
     1     2
     3     0