EZW.rar_EZW_matlab EZW

/* ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;;; 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. ;;; MODIFIED, 8/97: reflect1, reflect2, repeat, extend upgraded to ;;; work properly for non-symmetric filters. Added qreflect2 to handle ;;; even-length QMF's which broke under the reflect2 modification. ;;; ---------------------------------------------------------------- ;;; 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 functions are called internal_reduce and internal_expand and are 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. */ #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(), qreflect2(), 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 */ { "qreflect2", qreflect2 }, /* reflect image, including edge pixels for even-length QMF decompositions */ { "extend", Extend }, /* extend (reflect & invert) */ { "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="qreflect2"; edge_foos[i++].func=qreflect2; edge_foos[i].name="extend"; edge_foos[i++].func=Extend; 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) IS 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 IS 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... r_or_e - equal to one of the two constants EXPAND or REDUCE. -------------------------------------------------------------------- */ /* -------------------------------------------------------------------- nocompute() - Return zero for values where filter hangs over the edge. */ int nocompute(filt,x_dim,y_dim,x_pos,y_pos,result,r_or_e) register double *filt, *result; register int x_dim; int y_dim, x_pos, y_pos, r_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,r_or_e) register double *filt, *result; register int x_dim; int y_dim, x_pos, y_pos, r_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); } /* -------------------------------------------------------------------- reflect1() - Reflection through the edge pixels. Continuous, but discontinuous first derivative. This is the right thing to do if you are subsampling by 2, since it maintains parity (even pixels positions remain even, odd ones remain odd). */ int reflect1(filt,x_dim,y_dim,x_pos,y_pos,result,r_or_e) register double *filt, *result; register int x_dim; int y_dim, x_pos, y_pos, r_or_e; { int filt_sz = x_dim*y_dim; register int y_filt,x_filt, y_res, x_res; register int x_base = (x_pos>0)?(x_dim-1):0; register int y_base = x_dim * ((y_pos>0)?(y_dim-1):0); int x_overhang = (x_pos>0)?(x_pos-1):((x_pos<0)?(x_pos+1):0); int y_overhang = x_dim * ((y_pos>0)?(y_pos-1):((y_pos<0)?(y_pos+1):0)); int i; int mx_pos = (x_pos<0)?(x_dim/2):((x_dim-1)/2); int my_pos = x_dim * ((y_pos<0)?(y_dim/2):((y_dim-1)/2)); for (i=0; i<filt_sz; i++) result[i] = 0.0; if (r_or_e IS REDUCE) for (y_filt=0, y_res=y_overhang-y_base; y_filt<filt_sz; y_filt+=x_dim, y_res+=x_dim) for (x_filt=y_filt, x_res=x_overhang-x_base; x_filt<y_filt+x_dim;