The program showing "Error using - Matrix dimensions must agree. out = im2double(a) - im2double(d);"

a=imread('Whiteimage.jpg');
b=imread('vegetableimage.jpg');
c=rgb2gray(b);
d=im2bw(c);
out=im2double(a)-im2double(d);
se=strel('disk',6);
frameout=imdilate(out,se);

[L,n]=bwlabel(frameout,8);
s=regionprops(L,'Area','Centroid','BoundingBox','Perimeter');
imshow(b)

[Jan]

I've formatted your code tody. Please learn how to use the formatting tools in the forum.

[Zahin Eaman Uddin]

how can i learn use of the formatting tools?

[Jan]

Do you see the bar with icons directly on top of the field to type or edit your messages in the forum? On the right hand you find a small question mark. Click on it to get the help page (link).

I'm surprised that this is not trivial.

Answer 1

[Jan]

The error message is clear: a and d have different sizes. While d is a 2D matrix, a is most likely an RGB array with 3 dimensions. Check this using the debugger. Type this in the command window:

dbstop if error

Run the code again. When it stops at the error, check the sizes:

size(a)
size(d)

[Guillaume]

Actually, if the two images are the same width and height, it shouldn't matter if one is greyscale and the other RGB, at least on versions >= R2016b. With implicit expansion, the grey image would be subtracted from each colour channel.

Therefore, either the OP is using an old version of matlab (in which case use bsxfun for the subtraction) or the images are completely different size (in which case, maybe they should be resized to a common size?)