Stereo Vision Image Rectification

Hi,

Currently i'm working on program example for stereo image rectification as shown in

http://www.mathworks.com/help/vision/examples/stereo-image-rectification.html

I got some errors on imshowpair function like this :

Error using imfuse>parse_inputs (line 316) Argument 'method' failed validation with error: Expected METHOD to match one of these strings:

falsecolor, diff, blend, montage

The input, ''ColorChannels'', did not match any of the valid strings.

so then i changed the imshowpair into :

imshowpair(I1,I2,'falsecolor');

and it was working, my question why i can't use the colorchannels features ?

The second error came on showMatchedFeatures function. The error message was like this :

Undefined function 'showMatchedFeatures' for input arguments of type 'single'.

Error in Stereo (line 29) figure; showMatchedFeatures(I1, I2, matchedPoints1, matchedPoints2);

how to solve this problem ?

thanks