Create a frequency/orientation image
target = FOTarget(pattern,parms)
Purpose:
This target is a black and white image divided into a set of blocks.
Each block has a different spatial frequency pattern at one of several
orientations. The patterns increase in spatial frequency along the
horizontal dimension and change in orientation along the vertical
dimension. This pattern is well-suited for evaluating demosaicing and
spatial image processing.
The spatial patterns can be either square waves or sinusoids. At high spatial
frequencies, the optics in a real camera does not produce square waves. So,
in general we recommend using the sinusoidal format for testing.
The detailed parameters of the harmonic patterns and their orientations
are set in the parms structure, as explained below.
Example:
The number of blocks, spatial frequency values, and contrast are set by
the entries of the parms variable as in the example:
parms.angles = linspace(0,pi/2,5);
parms.freqs = [1,2,4,8,16];
parms.blockSize = 64;
parms.contrast = .8;
target = FOTarget('sine',parms);
imshow(target)
Copyright ImagEval Consultants, LLC, 2005.