Grouping variable must be a vector or a character array

I have done the following:

    I=imread('image.png');
    I2=im2double(I);
    cidx = fcm(I2,5);

When I tried running the following command:

     silhouette(I2,cidx)

I got the following error:

    Error using grp2idx (line 39)
    Grouping variable must be a vector or a character array.

    Error in silhouette (line 79)
    [idx,cnames] = grp2idx(clust);

How can I solve this issue?

Thanks.

Answer 1

[Walter Roberson]

The first output of fcm() is centroid coordinates, not membership information. Membership information would appear in the second output. See the example at http://www.mathworks.com/help/fuzzy/fcm.html

[med-sweng]

Thanks for your reply. So, in this case, what do you suggest?