am getting an error on filter function using this image called _ *sweets.png*_

am getting error on using this image called _ sweets.png_ if true % code

J =filter2(fspecial('sobel'),I); end

Error:

Undefined function 'conv2' for input arguments of type 'double' and attributes 'full 3d real'.

Error in filter2 (line 59) y = conv2(hcol, hrow, x, shape);

Error in last (line 15) J=filter2(fspecial('sobel'),I); end

Answer 1

[Rik]

In Matlab, a color image is 3D, the third dimension being the color channels. You need to convert it to a grayscale image (e.g. with rgb2gray).