[sallay]

我在Matlab2007和2008中想执行hough transform，我按照例子的代码，

>> RGB = imread('coins.png');
>> I = rgb2gray(RGB); % convert to intensity
>> BW = edge(I,'canny'); % extract edges
>> [H,T,R] = hough(BW,'RhoResolution',0.5,'ThetaResolution',0.5);

但是有如下的报错，

??? Undefined function or method 'houghmex' for input arguments of type 'double'.
Error in ==> hough at 83
h = houghmex(bw,rho,theta*pi/180);

2007和2008都是相同的问题，代码是按照help的例子，实在是想不通啊!
有没有高人能指点一下，先谢谢了！