sharpen_hist

create a mapping for minclookup to sharpen a volume histogram

sharpen_hist [options] <infile> <outfile>

DESCRIPTION

sharpen_hist sharpens (deconvolves) an intensity histogram using a Wiener filter. The input is a histogram file (produced by volume_hist) and the output is a sharpened histogram. This deconvolution step is central to the N3 non-uniformity correction algorithm, where sharpening the histogram helps estimate the bias field by separating the true tissue intensity distribution from the blurring effect of the non-uniformity.

OPTIONS

-clobber

Overwrite an existing output file.

-noclobber

Do not overwrite an existing output file (default).

-verbose

Print progress information.

-quiet

Do not print progress information.

-fwhm <val>

Set the full width at half maximum of the deconvolution kernel (default: 1).

-noise <val>

Set the noise level for the Wiener filter (default: 0.1).

-blur

Skip the deblurring step.

-min <val>

Set the bin value mapped to zero in the lookup table.

-max <val>

Set the bin value mapped to one in the lookup table.

-range <min> <max>

Set the range of bin values for the lookup table.

-debug

Save intermediate steps as matlab files for debugging.

EXAMPLES

sharpen_hist histogram.txt sharpened_histogram.txt

sharpen_hist -fwhm 0.5 -noise 0.05 histogram.txt sharpened.txt

AUTHOR

John G. Sled - McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University.

COPYRIGHTS

Copyright © 1998 by John G. Sled

SEE ALSO

sharpen_volume, volume_hist, nu_correct, nu_estimate