edges-orig.c

matlab的steel金字塔小波分解源代码

/* 
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;  File: edges.c
;;;  Author: Eero Simoncelli
;;;  Description: Boundary handling routines for use with convolve.c
;;;  Creation Date: Spring 1987.
;;;  MODIFIED, 6/96, to operate on double float arrays.
;;;  MODIFIED by dgp, 4/1/97, to support THINK C.
;;;  ----------------------------------------------------------------
;;;    Object-Based Vision and Image Understanding System (OBVIUS),
;;;      Copyright 1988, Vision Science Group,  Media Laboratory,  
;;;              Massachusetts Institute of Technology.
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
*/

/* 
This file contains functions which determine how edges are to be
handled when performing convolutions of images with linear filters.
Any edge handling function which is local and linear may be defined,
except (unfortunately) constants cannot be added.  So to treat the
edges as if the image is surrounded by a gray field, you must paste it
into a gray image, convolve, and crop it out...
The main convolution function is called internal_filter and is defined
in the file convolve.c.  The idea is that the convolution function
calls the edge handling function which computes a new filter based on
the old filter and the distance to the edge of the image.  For
example, reflection is done by reflecting the filter through the
appropriate axis and summing.  Currently defined functions are listed
below.  
*/

/*
#define DEBUG
*/

#include <stdio.h>
#include <math.h>
#include <string.h>
#include "convolve.h"

#define sgn(a)  ( ((a)>0)?1:(((a)<0)?-1:0) )
#define clip(a,mn,mx)  ( ((a)<(mn))?(mn):(((a)>=(mx))?(mx-1):(a)) )

int reflect1(), reflect2(), repeat(), zero(), Extend(), nocompute();
int ereflect(), predict();

/* Lookup table matching a descriptive string to the edge-handling function */
#if !THINK_C
	static EDGE_HANDLER edge_foos[] =
	  {
	    { "dont-compute", nocompute }, /* zero output for filter touching edge */
	    { "zero",     zero     },   /* zero outside of image */
	    { "repeat",   repeat   },   /* repeat edge pixel */
	    { "reflect1", reflect1 },   /* reflect about edge pixels  */
	    { "reflect2", reflect2 },   /* reflect image, including edge pixels  */
	    { "extend",   Extend   },   /* extend (reflect & invert) */
	    { "predict",  predict  },   /* predict based on portion covered by filt */
	    { "ereflect", ereflect },   /* orthogonal QMF reflection */
	  };
#else
	/*
	This is really stupid, but THINK C won't allow initialization of static variables in
	a code resource with string addresses. So we do it this way.
	The 68K code for a MATLAB 4 MEX file can only be created by THINK C.
	However, for MATLAB 5, we'll be able to use Metrowerks CodeWarrior for both 68K and PPC, so this
	cludge can be dropped when we drop support for MATLAB 4.
	Denis Pelli, 4/1/97. 
	*/
	static EDGE_HANDLER edge_foos[8];

	void InitializeTable(EDGE_HANDLER edge_foos[])
	{
		static int i=0;
		
		if(i>0) return;
		edge_foos[i].name="dont-compute";
		edge_foos[i++].func=nocompute;
		edge_foos[i].name="zero";
		edge_foos[i++].func=zero;
		edge_foos[i].name="repeat";
		edge_foos[i++].func=repeat;
		edge_foos[i].name="reflect1";
		edge_foos[i++].func=reflect1;
		edge_foos[i].name="reflect2";
		edge_foos[i++].func=reflect2;
		edge_foos[i].name="extend";
		edge_foos[i++].func=Extend;
		edge_foos[i].name="predict";
		edge_foos[i++].func=predict;
		edge_foos[i].name="ereflect";
		edge_foos[i++].func=ereflect;
	}
#endif

/*
Function looks up an edge handler id string in the structure above, and
returns the associated function 
*/
fptr edge_function(char *edges)
  {
  int i;

#if THINK_C
  InitializeTable(edge_foos);
#endif
  for (i = 0; i<sizeof(edge_foos)/sizeof(EDGE_HANDLER); i++)
    if (strcmp(edges,edge_foos[i].name) == 0)
      return(edge_foos[i].func);
  printf("Error: '%s' is not the name of a valid edge-handler!\n",edges);
  for (i=0; i<sizeof(edge_foos)/sizeof(EDGE_HANDLER); i++)
      {
      if (i==0) printf("  Options are: ");
      else printf(", ");
      printf("%s",edge_foos[i].name);
      }
  printf("\n");
  return(0);
  }

/* 
---------------- EDGE HANDLER ARGUMENTS ------------------------
filt - array of filter taps.
x_dim, y_dim - x and y dimensions of filt.
x_pos - position of filter relative to the horizontal image edges. Negative
       values indicate left edge, positive indicate right edge.  Zero 
       indicates that the filter is not touching either edge.  An absolute
       value of 1 indicates that the edge tap of the filter is over the 
       edge pixel of the image.
y_pos - analogous to x_pos.
result - array where the resulting filter will go.  The edge
       of this filter will be aligned with the image for application...
f_or_e - equal to one of the two constants EXPAND or FILTER.
-------------------------------------------------------------------- 
*/ 


/* --------------------------------------------------------------------
nocompute() - Return zero for values where filter hangs over the edge.
*/

int nocompute(filt,x_dim,y_dim,x_pos,y_pos,result,f_or_e)
  register double *filt, *result;
  register int x_dim;
  int y_dim, x_pos, y_pos, f_or_e;
  {
  register int i;
  register int size = x_dim*y_dim;

  if ( (x_pos>1) OR (x_pos<-1) OR (y_pos>1) OR (y_pos<-1) )
    for (i=0; i<size; i++)  result[i] = 0.0;
  else
    for (i=0; i<size; i++)  result[i] = filt[i];
  return(0);
  }

/* --------------------------------------------------------------------
zero() - Zero outside of image.  Discontinuous, but adds zero energy. */

int zero(filt,x_dim,y_dim,x_pos,y_pos,result,f_or_e)
  register double *filt, *result;
  register int x_dim;
  int y_dim, x_pos, y_pos, f_or_e;
  {
  register int y_filt,x_filt, y_res,x_res;
  int filt_sz = x_dim*y_dim;
  int x_start = ((x_pos>0)?(x_pos-1):((x_pos<0)?(x_pos+1):0));
  int y_start = x_dim * ((y_pos>0)?(y_pos-1):((y_pos<0)?(y_pos+1):0));
  int i;

  for (i=0; i<filt_sz; i++) result[i] = 0.0;

  for (y_filt=0, y_res=y_start;
       y_filt<filt_sz;
       y_filt+=x_dim, y_res+=x_dim)
    if ((y_res >= 0) AND (y_res < filt_sz))
      for (x_filt=y_filt, x_res=x_start;
	   x_filt<y_filt+x_dim;
	   x_filt++, x_res++)
	if ((x_res >= 0) AND (x_res < x_dim))
	  result[y_res+x_res] = filt[x_filt];
  return(0);
  }

/* --------------------------------------------------------------------
repeat() - repeat edge pixel.  Continuous, but content is usually
different from image.  
*/

int repeat(filt,x_dim,y_dim,x_pos,y_pos,result,f_or_e)
  register double *filt, *result;
  register int x_dim;
  int y_dim, x_pos, y_pos, f_or_e;
  {
  register int y_filt,x_filt, y_res,x_res;
  int filt_sz = x_dim*y_dim;
  int x_start = ((x_pos>0)?(x_pos-1):((x_pos<0)?(x_pos+1):0));
  int y_start = x_dim * ((y_pos>0)?(y_pos-1):((y_pos<0)?(y_pos+1):0));
  int i;

  for (i=0; i<filt_sz; i++) result[i] = 0.0;

  for (y_filt=0, y_res=y_start;
       y_filt<filt_sz;
       y_filt+=x_dim, y_res+=x_dim)
    for (x_filt=y_filt, x_res=x_start;
	 x_filt<y_filt+x_dim;
	 x_filt++, x_res++)
      result[((y_res>=0)?((y_res<filt_sz)?y_res:(filt_sz-x_dim)):0) 
 	     + ((x_res>=0)?((x_res<x_dim)?x_res:(x_dim-1)):0)]      
	+= filt[x_filt];
  return(0);
  }

/* --------------------------------------------------------------------
reflect2() - "Normal" image reflection.  The edge pixel is repeated,
then the next pixel, etc.  Continuous, attempting to maintain
"similar" content, but discontinuous first derivative.
*/

int reflect2(filt,x_dim,y_dim,x_pos,y_pos,result,f_or_e)
  register double *filt, *result;
  register int x_dim;
  int y_dim, x_pos, y_pos, f_or_e;
  {
  register int y_filt,x_filt, y_edge,x_edge;
  register int x_base = (x_pos>0)?(x_dim-1):0;
  register int y_base = (y_pos>0)?(x_dim*(y_dim-1)):0; 
  int filt_sz = x_dim*y_dim;
  int x_edge_dist = (x_pos>0)?(x_pos-x_dim-1):(x_pos+1);
  int y_edge_dist = x_dim * ((y_pos>0)?(y_pos-y_dim-1):(y_pos+1));
  int i;

  #ifdef DEBUG
    printf("(%d,%d)  ",y_pos,x_pos);
    if (x_pos==0) printf("\n");
  #endif

  for (i=0; i<filt_sz; i++) result[i] = 0.0;

  for (y_filt=0, y_edge=y_edge_dist;
       y_filt<filt_sz;
       y_filt+=x_dim, y_edge+=x_dim)
      {
      if (y_edge IS 0) y_edge+=x_dim;
      for (x_filt=y_filt, x_edge=x_edge_dist;
	   x_filt<y_filt+x_dim;
	   x_filt++, x_edge++)
	  {