MATLAB: Subtraction of two images

image analysis

I have two images with different dimension. I need to perform subtraction on it. I am not able to do it and don't know how to fix the error. Can somebody tell me the right code in matlab? i am unable to post images here. each time i do it i get error saying matrix dimension must agree. how shall i solve it
R=imread('If.jpg');
S=imread('j.jpg');
f8=R-S;
below is the description of my image u= imread('If.jpg');
whos Name Size Bytes Class Attributes
u 363x484x3 527076 uint8
v= imread ('j.jpg');
whos Name Size Bytes Class Attributes
v 900x1200x3 3240000 uint8
i am unable to subtract it because of the error minus Integers can only be combined with integers of the same class, or scalar doubles.
Error in ==> file1>filter_Callback at 695 f8=If-J;

Best Answer

You can not subtract images with different sizes the same way you can not subtract arrays with different lengths:
a=[1 2 3 4];
b=[1 2];
c=a-b; % -> !!!!! this will yield an error, dimensions must agree. Same for your images
Perform a crop of the biggest image with the dimensions of the smallest, use imcrop:
doc imcrop
and then subtract the smallest image and the crop from the biggest.
Related Question