% Create sampled function
ih = 512;  iw = 512;  numc = 400;
cr = floor(ih/2);  cc = floor(iw/2);
im = zeros(ih,iw);
for r=1:ih
  for c=1:iw
    th = atan2(cr-r, c-cc);
    im(r,c) = sin(th*numc);
  end
end

% Display
fh = figure;
imagesc(im);  colormap(gray);