How can I solve error: Arrays have incompatible sizes for this operation?

I run the matlab code and had an error that Arrays have incompatible sizes for this operation. I want a solution to it which again can apply to different images...

The operation that I used is :

A = logical(imread('7001-236.png'));
BW_groundTruth =logical(imread('Label7001-236.png'));
similarity = jaccard(A, BW_groundTruth)

Arrays have incompatible sizes for this operation.

Error in jaccard (line 126)

if any(size(A) ~= size(B))

Error in GT_jac_index (line 9)

similarity = jaccard(A, BW_groundTruth)

I tried to apply the following code to fix it but not workiking

    image2=imread('Label7001-236.png');
    newIm = imresize(image2, [309, 310]);
    imwrite(newIm,"Label7001-236.png")
    still have same error, how to fix it?

[Stephen23]

The reason is very simple, once you look at the array sizes:

A = logical(imread('7001-236.png'));
B = logical(imread('Label7001-236.png'));
size(A)

ans = 1×3

309 310 3

size(B)

ans = 1×2

309 310

Note that the JACCARD documentation clearly states that its 2nd input BW2 must be "...specified as a logical array of the same size as BW1."

Note that TMW could have written more robust code with ISEQUAL(SIZE(..),SIZE(..))

[yasmin ismail]

@Stephen23 yes the answer is:

ans =

309 310 3

ans =

309 310

there is different bewteen their sizes , so how to fix it , convert the label image to gray image althought its binary image already or what?

[Stephen23]

Given that all three pages/channels are exactly equal:

A = logical(imread('7001-236.png'));
isequal(A(:,:,1),A(:,:,2),A(:,:,3))

ans = logical
   1

you could simply use indexing to extract one channel.

[yasmin ismail]

@Stephen23 sorry I am new biggener in coding and matalab I didnt understand what is the benifit from using

logical(imread('7001-236.png'));

isequal(A(:,:,1),A(:,:,2),A(:,:,3))

I understood that image 7001-236.png is 3 channels which is different than label image , so I have to convert it to gray image to have same channel size of label image , then I can apply jaccard index, is it the right way?

[Torsten]

Use

similarity = jaccard(squeeze(A(:,:,1)), BW_groundTruth)

instead of

similarity = jaccard(A, BW_groundTruth)

[yasmin ismail]

@Torsten thanks its working now

[Stephen23]

Note that SQUEEZE does absolutely nothing there, you can safely get rid of it:

similarity = jaccard(A(:,:,1), BW_groundTruth)

[yasmin ismail]

@Stephen23 thanks alot its working too