NAME
nonfft_xformfilter - arrange frequency filter for use with
various transforms
SYNOPSIS
#include <stdio.h>
#include <stdlib.h>
#include "CVIPdef.h"
#include "CVIPimage.h"
#include "CVIPxformfilter.h"
Image *nonfft_xformfilter(Image *imgP, int block_size, int
dc, FILTER_TYPE filtertype, int p1, float p2, int order)
<imgP> - pointer to an image
<block_size> - block size used in transform
<dc> - 1 = keep DC, 2 = discard DC
<filtertype> - one of:
IDEAL_LOW
BUTTER_LOW
IDEAL_HIGH
BUTTER_HIGH
IDEAL_BAND
BUTTER_BAND
IDEAL_REJECT
BUTTER_REJECT
HIGH_FREQ_EMPHASIS
<p1> - for IDEAL_LOW, BUTTER_LOW, IDEAL_HIGH,
BUTTER_HIGH: cutoff frequency
- for IDEAL_BAND, BUTTER_BAND, IDEAL_REJECT,
BUTTER_REJECT: inner cutoff frequency
<p2> - for IDEAL_LOW, BUTTER_LOW, IDEAL_HIGH,
BUTTER_HIGH: set to -1
- for IDEAL_BAND, BUTTER_BAND, IDEAL_REJECT,
BUTTER_REJECT: outer cutoff frequency
- for HIGH_FREQ_EMPHASIS: emphasis offset
<order> - Butterworth filter order, otherwise -1
PATH
$CVIPHOME/XFORMFILTER/nonfft_filter.c
DESCRIPTION
This function is an internal function called by frequency-
domain filters to arrange frequency filter values for use
with various transforms. For example, the dc value of the
FFT transform is placed in the center of the image, while
the dc value of the DCT transform is placed in the upper-
left corner of the image. The nonfft_xformfilter function
places the center of the filter in the appropriate location.
Not normally called directly by a user.
TYPES AND CONSTANTS
typedef enum {
IDEAL_LOW = 1,
BUTTER_LOW = 2,
IDEAL_HIGH =3 ,
BUTTER_HIGH = 4,
IDEAL_BAND = 5,
BUTTER_BAND = 6,
IDEAL_REJECT = 7,
BUTTER_REJECT = 8,
HIGH_FREQ_EMPHASIS = 9
} FILTER_TYPE;
RETURN VALUES
Pointer to an appropriate filter image
HISTORY
History information recorded: None
SEE ALSO
libxformfilter
AUTHOR
Copyright (C) 1996 SIUE - by Scott Umbaugh, Simon Low, and
Greg Hance.