what the right function ?

any body can help me?

i'm a newbie with matlab.

why this function error. "function I= checkered(N,s)"

% Prepare image
     f = zeros(30,30);
     f(5:24,13:17) = 1;
     imshow(f,'notruesize')

       % Compute Fourier Transform
       F = fft2(f,256,256);
       F = fftshift(F); % Center FFT

       % Measure the minimum and maximum value of the transform amplitude
       min(min(abs(F))) %   0
       max(max(abs(F))) % 100
       imshow(abs(F),[0,100]); colormap(jet); colorbar
       imshow(log(1+abs(F)),[0,3]); colormap(jet); colorbar
             % * What is the main difference between representing the amplitude and its logarithm?

       % Look at the phases
       imshow(angle(F),[-pi,pi]); colormap(jet); colorbar

             % * Try with other images
       f = imread('fotokanker1.jpg');
       f = ind2gray(f,gray(256));

            %  * Or more patterned from Yamitani (at Caltech Univ.) homepage.
             % * Checkered images
       function I= checkered(N,s)
       % This function returns a checkered image of size N
       % and with a check size of s

       I=zeros(N,N);
       for i=1:N,
           for j=1:N,
               if (mod(floor(i/s)+floor(j/s),2)==0) I(i,j)=1; end;
           end;
       end;

       f=checkered(256,32); imshow(f);

[Image Analyst]

In the Image Processing Toolbox, there is a checkerboard() function.

Answer 1

[per isakson]

If checkered is supposed to be a nested function if must be closed with the keyword end.

[deniel munthe]

owh, ok .

thanks a lot of.

Answer 2

[Wayne King]

It looks to me like this function is ok. I mean you don't need the semicolons after the ends, but ok fine.

Did you save this checkered.m file somewhere on your path? Then you can call it with:

   f=checkered(256,32); imshow(f);

Don't try to execute this whole thing as a script, maybe that is what you are doing wrong. Pull out the function and save that in a separate checkered.m file.

[deniel munthe]

yes I save it with the name checkered.m

so I should not combine the functions of these at once.

Thank you very much