What should I insert for 'MAP' in immovie(X,MAP)?

I'm not sure what to put for the input argument 'MAP' in immovie(X,MAP). I have the X (a 900x1200x1x60 matrix) but any input I have for MAP resullts in error. I've tried variations of gray(256) and colormap. Each matrix is in color (but are still 2D matrices) so I expect my movie to also be in color. This is the error I am getting.

Error using im2uint8 (line 83) Invalid indexed image: an index was less than 1.

Error in immovie>parse_inputs (line 88) X = im2uint8(X,'indexed');

Error in immovie (line 38) [X,map] = parse_inputs(varargin{:});

Error in TweetAnalysis (line 993) mov=immovie(statemat,double(colormap));

Answer 1

[Prashant Arora]

Hi Maya,

The reason you are getting this error is because the function call immovie(X,map) requires X to be an indexed image. This means that the values of X must greater than 1. To read more about indexed images, you can check out the following link

https://www.mathworks.com/help/matlab/creating_plots/image-types.html#f2-155

If your image has intensity values from 0 to 1 and you would like to use a colormap of gray(256), you need to scale the image intensity to [1 256]. You can do by using something like this:

X =  X.*255 + 1 % Add 1 to start index from 1

I hope this helps!