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.