DATAMANIP commands
PROGRAM NAME
kinverse - Inverse Filtering (Restoration) in Fourier Frequency Domain
DESCRIPTION
kinverse
performs restoration of data in the spatial domain by inverse filtering in
the frequency domain. The idea is to deconvolve the blurring function
from the blurred data. A few problems exist in performing this operation,
as described in great detail in any good image processing book.
The major difficulty lies in how small the denominator is allowed to be
before you call it garbage. The value chosen is supplied as the
-t thresh value. Ideally, this will be just above the noise floor in the
image, but experimentation is the best guide here.
kinverse
places zeros in the output data for those data points where the PSF data object
magnitude is below the threshold. In this respect, kinverse is actually an
implementation of a pseudoinverse filter.
Note that the input data objects will be treated simply as a field of complex
data, presumably obtained by application of an FFT, although the data could
be generated by many other means. The output data will be either KCOMPLEX if
the input data is any type other than KDCOMPLEX. Otherwise, the output will be
of type KDCOMPLEX. Data objects with maps attached are not supported.
REQUIRED ARGUMENTS
- -i1
-
type: infile
desc: source data object (FFT)
- -i2
-
type: infile
desc: PSF data object (FFT)
- -o
-
type: outfile
desc: filtered data object (FFT)
OPTIONAL ARGUMENTS
- -t
-
type: double
desc: filter threshold (magnitude)
default: 1
bounds: value >= 0.0
EXAMPLES
SEE ALSO
RESTRICTIONS
REFERENCES
R.C. Gonzalez, P. Wintz, "Digital Image Processing", Addison-Wesley 1987,
ISBN 0-201-11026-1, pp. 221-224.
COPYRIGHT
Copyright (C) 1993 - 1997, Khoral Research, Inc. ("KRI") All rights reserved.