Error using rgb2array and gpuArray

I ran the given commands as directed in rgb2gray help, but got errors.

I = gpuArray(imread('board.tif')); % this worked fine
J = rgb2gray(I); % error in this line
figure, imshow(I), figure, imshow(J);

Errors.

Error using imapplymatrix>checkOutputClass (line 145)
The output class must be a valid numeric datatype.

Error in imapplymatrix (line 69)
  checkOutputClass(outputClass);

Error in rgb2gray (line 62)
  I = imapplymatrix(coef, X, class(X));

Please help me with this

Answer 1

[Edric Ellis]

You need to be using at least R2013b for RGB2GRAY to operate on gpuArray data. See the Image Processing Toolbox release notes.