Ramiro Jordan and Donna Koechner
COPYRIGHT
Copyright 1992, University of New Mexico. All rights
reserved.
*********************************************************************************
Documentation for avs module dfht
INPUT
1. img - a pointer to an xvimage structure containing
the signal to be transformed
2. scale_flag - an integer which specifies whether the
output from the transform should be left unscaled(0),
scaled by 1/N(1), or scaled by 1/sqrt(N)(2).
3. dir_flag - an integer which specifies whether the
transform should be taken down vectors(0) or across
bands(1).
OUTPUT
1. img - the input image is overwritten and the output
is returned in its place. Be careful not to overwrite
important data.
dfht returns 1 upon success and 0 on failure.
DESCRIPTION
dfht performs a 1-D Fast Hadamard Transform on a signal.
The Hadamard Transform uses a series of pulses as its basis
functions. This program uses the successive doubling algor-
ithim to implement a Fast Transform. The output coeffi-
cients are, by definition, in sequency order.
The output data may be scaled by 1/N, 1/sqrt(N), or not
scaled at all. The default is to not scale the data at all.
The only difference between a forward and a reverse Hadamard
Transform is the scaling factor, so this routine functions
as both a forward and reverse transform provided that one of
the transforms (forward OR reverse) is set to scale by 1/N
and the other performs no scaling.
Signals may be processed either across bands or in the vec-
tor direction. The default data processing direction is
across bands.
The Following references were used in creating this
program :
1. "Digital Image Processing, Second Edition"
Rafael C. Gonzale
Paul Wintz
Addison-Wesley Publishing Company, Reading Mas-
sachusetts, 1987
2. "The C User's Journal", July 1989, "The Fast Walsh
Transform", p101
Ian AshDown
SEE ALSO
dfht(1), intro(3), vipl(3), verror(3), vutils(3) lvfwt2d(3)
RESTRICTIONS
dfht only operates on data of type VFF_TYP_FLOAT. Images
using maps are not accepted and neither is data with expli-
cit locations included.
AUTHOR
Per Lysne
COPYRIGHT
Copyright 1992, University of New Mexico. All rights
reserved.
*********************************************************************************
Documentation for avs module dhart1d
INPUT
image contains the signal data to be transformed.
trans_dir specifies the transform direction. 0 indi-
cates the inverse transform, 1 indicates the
forward transform. This is only useful when
center_opt is set to 1 (center).
center_opt centering choice: 1 for centered, 0 for not
centered.
scale_opt scaling choice: 0 for no scaling, 1 for mul-
tiplying by 1/n, 2 for multiplying by
1/sqrt(n), where n is the number of data
points.
process_dir processing direction: 0 for vector processing
or 1 for band oriented processing.
OUTPUT
image holds the result of the transform.
Return Value: 1 on success, 0 on failure.
DESCRIPTION
1D Forward Hartley Transform. Performs the 1D forward Hart-
ley transform of a sequence. It can operate on Real data.
The transform can be centered about its N/2 term by setting
the -c option to 1. (This is the default setting.) If -c is
set to 0, the transform will not be centered.
The output data can be scaled by 1/N or by 1/sqrt(N) if
desired by using the -s option. The default setting is to
leave the output data unscaled (-s = 0). If -s is set to 1,
the output data is scaled by 1/N, where N in the number of
points in the data sequence. The output can be scaled by
1/sqrt(N) by setting -s to 2.
The default data processing direction for dfft1d is in the
vector direction. This means that data stored in multiband
format will be processed as a set of data sequences, where
each sequence corresponds to a pixel location, and the
points of each sequence are defined by the bands correspond-
ing to that pixel location. The direction of processing can
be changed so that each band is processed as a signal
(instead of each vector being a signal) by setting the -d
option to 1.
SEE ALSO
dhart1d(1), intro(3), vipl(3), verror(3), vutils(3)
AUTHOR
Jeremy Worley
COPYRIGHT
Copyright 1992, University of New Mexico. All rights
reserved.
*********************************************************************************
Documentation for avs module difft1d
INPUT
image pointer to VIFF structure containing image
data to be processed.
center_opt centering choice: 0 for not centered, 1 for
centered.
scale_opt scaling choice: 0 for no scaling, 1 for mul-
tiplying by 1/n, 2 for multiplying by
1/sqrt(n), where n is the number of data
points.
procdir process direction: 0 indicated vector
oriented processing, 1 indicates band
oriented processing.
OUTPUT
image pointer to VIFF structure containing image
data after processing.
Return Value: 1 on success, 0 on failure.
DESCRIPTION
performs the 1D inverse Fourier transform on a set of data
sequences. It can operate on Real and Complex data. NOTE:
complex data is expected to be in rectangular (not polar)
form. The output data type is VFF_TYP_COMPLEX.
The transform can be centered about its N/2 term by setting
the -c option to 1. If -c is set to 0, the transform will
not be centered (This is the default setting.).
The output data can be scaled by 1/N or by 1/sqrt(N) if
desired by using the -s option. The default setting is to
leave the output data unscaled (-s = 0). If -s is set to 1,
the output data is scaled by 1/N, where N in the number of
points in the data sequence. The output can be scaled by
1/sqrt(N) by setting -s to 2.
The default data processing direction for difft1d is in the
vector direction. This means that data stored in multiband
format will be processed as a set of data sequences, where
each sequence corresponds to a pixel location, and the
points of each sequence are defined by the bands correspond-
ing to that pixel location. The direction of processing can
be changed so that each band is processed as a signal
(instead of each vector being a signal) by setting the -d
option to 1.
SEE ALSO
difft1d(1), intro(3), vipl(3), verror(3), vutils(3)
AUTHOR
Ramiro Jordan and Donna Koechner
COPYRIGHT
Copyright 1992, University of New Mexico. All rights
reserved.
*********************************************************************************
Documentation for avs module dihart1d
INPUT
-i input data file (xviff file)
-o resulting output file (xviff file)
[-c] select to center (1) or not to center (0) the transform
[-d] data processing direction (0 = down vectors, 1 = across bands)
[-s] scale fft by 1, 1/N or 1/sqrt(N)
[-V] Gives the version for dihart1d
[-U] Gives the usage for dihart1d
[-P] prompts for command line options
[-A[file1]] creates the answer file called dihart1d.ans
[-a[file1]] uses dihart1d.ans as answer file
DESCRIPTION
1D Inverse Hartley Transform. Performs the 1D inverse Hartley
transform of a sequence. It can operate on Real data.
The transform can be centered about its N/2 term by setting the
-c option to 0. (This is the default setting.) If -c is set to
1, the transform will not be centered.
The output data can be scaled by 1/N or by 1/sqrt(N) if desired
by using the -s option. The default setting is to leave the
output data unscaled (-s = 0). If -s is set to 1, the output data
is scaled by 1/N, where N is the number of points in the data sequence.
The output can be scaled by 1/sqrt(N) by setting -s to 2.N
The default data processing direction for dfft1d is in the vector
direction. This means that data stored in multiband format will
be processed as a set of data sequences, where each sequence corresponds
to a pixel location, and the points of each sequence are defined
by the bands corresponding to that pixel location. The direction of processing
can be changed so that each band is processed as a signal (instead
of each vector being a signal) by setting the -d option to 1.
SEE ALSO
intro(1), verror(3), vgparms(3), vutils(3), ldihart1d(3)
COPYRIGHT
Copyright 1991, University of New Mexico. All rights reserved.
Documentation for avs module dmpp
INPUT
image pointer to VIFF structure containing image
data to be processed.
mode determines type of data desired (0 = magni-
tude, 1 = power, 2 = phase).
output magnitude or power output option: 0 = magni-
tude or power; 1 = log(magnitude or power); 2
= log(magnitude or power +1); 3 =
ln(magnitude or power); 4 = ln(magnitude or
power +1).
phase phase output option: 0 = radians; 1 =
degrees.
direction process direction: 0 indicated vector
oriented processing, 1 indicates band
oriented processing.
OUTPUT
image pointer to VIFF structure containing image
data after processing.
Return Value: 1 on success, 0 on failure.
DESCRIPTION
determines the magnitude, power, or phase of each 1-D data
point in the input data file.
dmpp will find the 1-D magnitude, power, or phase of each
data point. If magnitude or power is selected, it can gen-
erate the log or natural log of the result, or the log or
natural log of the result +1.
If phase is selected, then dmpp can generate either the
radian or degree result.
dmpp does not work on explicit location data and will return
an error when such a file is encountered. No output file
will be created. dmpp works only on VFF_TYP_FLOAT or
VFF_TYP_COMPLEX data files.
Input/Output Files
The input file must be of type VFF_TYP_FLOAT or
VFF_TYP_COMPLEX. The output file returned will be the same
size of the input file and the type will be VFF_TYP_FLOAT.
Process direction
Data can be processed with either band or vector orientation
(-d option). The default data processing direction is in
the vector direction (-d = 0). This means that data stored
in multiband format will be processed as a set of data
sequences, where each sequence corresponds to a pixel loca-
tion, and the points of each sequence are defined by the
bands corresponding to that pixel location. The direction
of processing can be changed so that each band is processed
as a signal (instead of each vector being a signal) by set-
ting the -d option to 1.
SEE ALSO
dmpp(1), intro(3), vipl(3), verror(3), vutils(3)
RESTRICTIONS
dmpp works only on VFF_TYP_COMPLEX and VFF_TYP_FLOAT.
dmpp does not work on explicit location data and will
return an error when such a data file is encountered. -
bugs_end
AUTHOR
Ramiro Jordan, Jeremy Worley
COPYRIGHT
Copyright 1992, University of New Mexico. All rights
reserved.
*********************************************************************************