What is the problem with my function to compute the cosine similarity of two images?

I am using a script to compute the cosine similarity of two images.

I first convert the images to vectors:

Img1 = imread('test1.jpg')
Img2 = imread('test2.jpg')

ImgVector1 = Img1(:)
ImgVector2 = Img2(:)

I then use the script to compute the cosine similarity between the vectors:

cossimnew(ImgVector1,ImgVector2)

That function is as follows:

function s=cossimnew(actual,estimate)
[m,n]=size(actual);
if n==1
  s=((estimate'*actual)/(norm(estimate)*norm(actual)))';
else
  for i=1:n,
    x=norm(estimate(:,i))*norm(actual(:,i));
    if x ~= 0
        s(i)=(estimate(:,i)'*actual(:,i))/x;
    else
      s(i)=NaN;
    end
  end
end
  s=s';

However I have been getting the following error:

Error using  * 
MTIMES is not fully supported for integer classes. At least one input must be
scalar.
To compute elementwise TIMES, use TIMES (.*) instead.

Error in cossimnew (line 8)

Can anyone point me in the right direction?

Thanks so much.

Answer 1

[David Sidhu]

I had to convert the vector to floating point numbers.

Doing the following led to the function working (added the double function):

I1 = imread('test1.jpg');
I2 = imread('test2.jpg');

IV1 = double(I1(:));
IV2 = double(I2(:));

cossimnew(IV1,IV2)

Answer 2

[Spencer Chen]

Please read Matlab documentation on the differences between the "*" and ".*" notations. Also please read more about vector operations and vectorizing operations in Matlab.