??? Undefined function or variable 'blur' Why is that

when compiling this code I'm getting an error

Warning: Unable to determine the number of frames in this file. ??? Undefined function or variable 'blur'.

Error in ==> ReadVideo at 22 IDX = kmeans(blur,2);

vid = 'N1.mpg';

shainObj = mmreader(vid);

nFrames = shainObj.NumberOfFrames;
vidHeight = shainObj.Height;
vidWidth = shainObj.Width;

% Preallocate movie structure.
mov(1:nFrames) = ...
    struct('cdata', zeros(vidHeight, vidWidth, 3, 'uint8'),...
           'colormap', []);

% Read one frame at a time.
for k = 1 : nFrames
    mov(k).cdata = read(shainObj, k);
    image = mov(k).cdata;
    imagegray = rgb2gray(image);
    imagegray = imresize(imagegray, 0.2);
    blur(k) = fmeasure(imagegray, 'GRAE', '');
end
IDX = kmeans(blur,2);
sum1 = 0;
sum2 = 0;
for k = 1 : nFrames
    if IDX(k) == 1
        sum1 = sum1 + 1;
    else
        sum2 = sum2 + 1;
    end
end
if sum1 > sum2
    normal = sum1;
    blured = sum2;
else
    normal = sum2;
    blured = sum1;
end
disp('blur metrics for the input video');
disp(sprintf('Total frames: %d',nFrames));
disp(sprintf('Normal frames: %d',normal));
disp(sprintf('Blured frames: %d',blured));

Answer 1

[Mischa Kim]

Shehan, the error message seems to indicate that MATLAB is not able to determine the number of frames in

 nFrames = shainObj.NumberOfFrames;

which would mean that the for loop is not executed (I assume) and therefore no values are assigned to blur(k). As a result MATLAB is not able to execute

 IDX = kmeans(blur,2);

To start debugging, remove the semi-colon in nFrames = shainObj.NumberOfFrames; to see the content of nFrames. You could do the same in the loops to see if they are execute.

Alternatively, use the debugger functionality in MATLAB to step through the code line by line.

[Shehan]

I tried what you said But no luck. I change the input video then it works What can be the problem is

but then i got an error message saying

*??? Undefined function or method 'fmeasure' for input arguments of type 'uint8'.

Error in ==> ReadVideo at 20 blur(k) = fmeasure(imagegray, 'GRAE', '');*

[Image Analyst]

fmeasure() is probably some custom written function. Ask whomever you got this code for. They probably forgot to give you one of the m-files.