Why do I have this error when using indexImages ??

When I tried ti run this code which I copied from MATLAB documentation:

setDir  = fullfile(toolboxdir('vision'),'visiondata','imageSets','cups');
imds = imageDatastore(setDir);
imageIndex = indexImages(imds);

I got this error

Error using indexImages
Expected input number 1, imgSet, to be one of these types:

imageSet

Instead its type was matlab.io.datastore.ImageDatastore.

Error in indexImages>parseInputs (line 125)
validateattributes(imgSet, {'imageSet'},{'scalar'}, mfilename, 'imgSet',1);

Error in indexImages (line 99)
[bag, params] = parseInputs(imgSet, varargin{:});

Why? could anyone please clarify? I'm pretty novice in MATLAB, so I would be grateful if you give me very clear answer. Thanks.

[Walter Roberson]

Odd.

Which MATLAB release are you using?

[amal fahad]

Thanks for the reply Im using R2016a

Answer 1

[Walter Roberson]

In R2016a and earlier, indexImages did not permit an imageDataStore to be passed to it. You are looking at R2016b documentation but trying to operate with an earlier version. The R2016a documentation for the function is at http://www.mathworks.com/help/releases/R2016a/vision/ref/indeximages.html