Index exceeds matrix dimensions. ?

Hear is my code

 %%Get Full Image Data
 % ENVI Import Cube and Register images
 datafile = '0604img-17_FlatField';
 hdrfile = '0604img-17_FlatField.hdr';

 %%Read ENVI Files
 [im, hdr] = enviread([old '\' datafile],[old  '\' hdrfile]);
 img = imrotate(im,90, 'nearest'); 
 figure; imshow(img(:,:,124));
 %d = reshape(textread('listplot.txt', '%s'),1,12)';
 %list of coordinates as x and y 
 load('listp.txt');
 for i = 1:12
         % pixval(i) = i+ img(d,:);
         pixval(i) = i+ img(VarName1,VarName2,:);
 end

It says it exceeds matrix dimentions. Some info: the "load (listp.txt) " outputs 2 list VarName1 12x1 double and VarName2 12x1 double. What i was doing before to call the information was to

     pixval = img(74,100,:)

this gave me a 1x1x361 matrix with all the data of that point. What I want to do is store the multiple points without having to create a variable for each (I.E. pixval1, pixval2 ext..)

Answer 1

[Adam]

By the sounds of it you want:

pixval(i) = i+ img(VarName1(i),VarName2(i),:);

rather than using the full VarName1 and VarName2 every time if they are length 12 vectors.

[Shane]

Yes the vectors in VarName1 and and VarName2 are length 12. I tried this and it still says Index exceeds matrix dimensions.

[Adam]

Well, I guess the obvious next question is what is the range of the values in VarName1 and VarName2 relative to img?

Actually, looking at it again I imagine the error comes from the pixval(i) assignment.

img(VarName1,VarName2,:) is going to return a vector of values so I imagine you need:

pixval(i,:) = i + squeeze( img(VarName1(i),VarName2(i),:) );

or something similar to that.

You should probably pre-allocate pixval too, but that is just for efficiency and isn't going to affect whether the code works or not in this case.

[Shane]

Thanks Adam, this gave me direction for what I needed to change to make it work

pixval=zeros(361,12);
for i = 1:12

        pix =  img(VarName2(i),VarName1(i),:);
        pixval(:,i)=pix(:);

end