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/* Copyright (c) 1986 Regents of the University of California */ |
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#ifndef lint |
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static char SCCSid[] = "$SunId$ LBL"; |
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static const char RCSid[] = "$Id$"; |
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#endif |
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|
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/* |
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* pf3.c - routines for gaussian and box filtering |
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* |
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* 8/13/86 |
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*/ |
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|
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< |
#include <stdio.h> |
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#include "pfilt.h" |
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|
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< |
#include "color.h" |
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> |
#define RSCA 1.13 /* square-radius multiplier: sqrt(4/PI) */ |
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> |
#define TEPS 0.2 /* threshold proximity goal */ |
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> |
#define REPS 0.1 /* radius proximity goal */ |
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|
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< |
#define FTINY 1e-7 |
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float *gausstable; /* gauss lookup table */ |
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|
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extern double rad; /* output pixel radius for filtering */ |
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float *ringsum; /* sum of ring values */ |
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short *ringwt; /* weight (count) of ring values */ |
| 20 |
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short *ringndx; /* ring index table */ |
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float *warr; /* array of pixel weights */ |
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|
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extern int nrows; /* number of rows for output */ |
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extern int ncols; /* number of columns for output */ |
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> |
#define lookgauss(x) gausstable[(int)(20.*(x)+.5)] |
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|
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extern int boxfilt; /* do box filtering? */ |
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static double pickfilt(double p0); |
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> |
static void sumans(int px, int py, int rcent, int ccent, double m); |
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|
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extern int xres, yres; /* resolution of input */ |
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|
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extern double x_c, y_r; /* conversion factors */ |
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|
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extern int xrad; /* x window size */ |
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extern int yrad; /* y window size */ |
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|
| 33 |
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extern int barsize; /* size of input scan bar */ |
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extern COLOR **scanin; /* input scan bar */ |
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extern COLOR *scanout; /* output scan line */ |
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|
| 37 |
< |
extern char *progname; |
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|
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float *exptable; /* exponent table */ |
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|
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#define lookexp(x) exptable[(int)(-10.*(x)+.5)] |
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|
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|
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initmask() /* initialize gaussian lookup table */ |
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void |
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initmask(void) /* initialize gaussian lookup table */ |
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{ |
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extern char *malloc(); |
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extern double exp(); |
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register int x; |
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int gtabsiz; |
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double gaussN; |
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double d; |
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int x; |
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|
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exptable = (float *)malloc(100*sizeof(float)); |
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if (exptable == NULL) { |
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fprintf(stderr, "%s: out of memory in initmask\n", progname); |
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quit(1); |
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} |
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for (x = 0; x < 100; x++) |
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exptable[x] = exp(-x*0.1); |
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gtabsiz = 444*CHECKRAD*CHECKRAD; |
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gausstable = (float *)malloc(gtabsiz*sizeof(float)); |
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if (gausstable == NULL) |
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goto memerr; |
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d = x_c*y_r*0.25/(rad*rad); |
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gausstable[0] = exp(-d); |
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for (x = 1; x < gtabsiz; x++) |
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if (x*0.05 <= d) |
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gausstable[x] = gausstable[0]; |
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else |
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gausstable[x] = exp(-x*0.05); |
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if (obarsize == 0) |
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return; |
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/* compute integral of filter */ |
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gaussN = PI*d*exp(-d); /* plateau */ |
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for (d = sqrt(d)+0.05; d <= RSCA*CHECKRAD; d += 0.1) |
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gaussN += 0.1*2.0*PI*d*exp(-d*d); |
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/* normalize filter */ |
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gaussN = x_c*y_r/(rad*rad*gaussN); |
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for (x = 0; x < gtabsiz; x++) |
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gausstable[x] *= gaussN; |
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/* create ring averages table */ |
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ringndx = (short *)malloc((2*orad*orad+1)*sizeof(short)); |
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if (ringndx == NULL) |
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goto memerr; |
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for (x = 2*orad*orad+1; --x > orad*orad; ) |
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ringndx[x] = -1; |
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do |
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ringndx[x] = sqrt((double)x); |
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while (x--); |
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ringsum = (float *)malloc((orad+1)*sizeof(float)); |
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ringwt = (short *)malloc((orad+1)*sizeof(short)); |
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warr = (float *)malloc(obarsize*obarsize*sizeof(float)); |
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if ((ringsum == NULL) | (ringwt == 0) | (warr == NULL)) |
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goto memerr; |
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return; |
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memerr: |
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fprintf(stderr, "%s: out of memory in initmask\n", progname); |
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quit(1); |
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} |
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|
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dobox(csum, xcent, ycent, c, r) /* simple box filter */ |
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COLOR csum; |
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int xcent, ycent; |
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int c, r; |
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void |
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dobox( /* simple box filter */ |
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COLOR csum, |
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int xcent, |
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int ycent, |
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int c, |
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int r |
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) |
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{ |
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static int wsum; |
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static double d; |
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static int y; |
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register int x; |
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register COLOR *scan; |
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|
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int wsum; |
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double d; |
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int y; |
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int x, offs; |
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COLOR *scan; |
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|
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wsum = 0; |
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setcolor(csum, 0.0, 0.0, 0.0); |
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for (y = ycent+1-yrad; y <= ycent+yrad; y++) { |
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if (y < 0 || y >= yres) |
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continue; |
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d = y_r < 1.0 ? y_r*y - r : y - ycent; |
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if (d > 0.5+FTINY || d < -0.5-FTINY) |
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continue; |
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for (y = ycent+1-ybrad; y <= ycent+ybrad; y++) { |
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if (y < 0) continue; |
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if (y >= yres) break; |
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d = y_r < 1.0 ? y_r*y - (r+.5) : (double)(y - ycent); |
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if (d < -0.5) continue; |
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if (d >= 0.5) break; |
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scan = scanin[y%barsize]; |
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for (x = xcent+1-xrad; x <= xcent+xrad; x++) { |
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if (x < 0 || x >= xres) |
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for (x = xcent+1-xbrad; x <= xcent+xbrad; x++) { |
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offs = x < 0 ? xres : x >= xres ? -xres : 0; |
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if (offs && !wrapfilt) |
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continue; |
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d = x_c < 1.0 ? x_c*x - c : x - xcent; |
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if (d > 0.5+FTINY || d < -0.5-FTINY) |
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continue; |
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d = x_c < 1.0 ? x_c*x - (c+.5) : (double)(x - xcent); |
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if (d < -0.5) continue; |
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if (d >= 0.5) break; |
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wsum++; |
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addcolor(csum, scan[x]); |
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addcolor(csum, scan[x+offs]); |
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} |
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} |
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if (wsum > 1) |
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scalecolor(csum, 1.0/wsum); |
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if (wsum > 1) { |
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d = 1.0/wsum; |
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scalecolor(csum, d); |
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} |
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} |
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|
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|
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dogauss(csum, xcent, ycent, c, r) /* gaussian filter */ |
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COLOR csum; |
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int xcent, ycent; |
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int c, r; |
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void |
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dogauss( /* gaussian filter */ |
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COLOR csum, |
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int xcent, |
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int ycent, |
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int c, |
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int r |
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) |
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{ |
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static double dy, dx, weight, wsum; |
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static COLOR ctmp; |
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static int y; |
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register int x; |
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register COLOR *scan; |
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double dy, dx, weight, wsum; |
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COLOR ctmp; |
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int y; |
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int x, offs; |
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COLOR *scan; |
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|
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wsum = FTINY; |
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setcolor(csum, 0.0, 0.0, 0.0); |
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for (y = ycent-yrad; y <= ycent+yrad; y++) { |
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if (y < 0 || y >= yres) |
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continue; |
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if (y < 0) continue; |
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if (y >= yres) break; |
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dy = (y_r*(y+.5) - (r+.5))/rad; |
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scan = scanin[y%barsize]; |
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for (x = xcent-xrad; x <= xcent+xrad; x++) { |
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if (x < 0 || x >= xres) |
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offs = x < 0 ? xres : x >= xres ? -xres : 0; |
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if (offs && !wrapfilt) |
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continue; |
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dx = (x_c*(x+.5) - (c+.5))/rad; |
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weight = lookexp(-(dx*dx + dy*dy)); |
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> |
weight = lookgauss(dx*dx + dy*dy); |
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wsum += weight; |
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copycolor(ctmp, scan[x]); |
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copycolor(ctmp, scan[x+offs]); |
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scalecolor(ctmp, weight); |
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addcolor(csum, ctmp); |
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} |
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} |
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scalecolor(csum, 1.0/wsum); |
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weight = 1.0/wsum; |
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> |
scalecolor(csum, weight); |
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} |
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> |
|
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> |
|
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void |
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dothresh( /* gaussian threshold filter */ |
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int xcent, |
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int ycent, |
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int ccent, |
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int rcent |
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) |
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{ |
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double d; |
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> |
int r, y, offs; |
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> |
int c, x; |
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> |
float *gscan; |
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> |
/* compute ring sums */ |
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memset((char *)ringsum, '\0', (orad+1)*sizeof(float)); |
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> |
memset((char *)ringwt, '\0', (orad+1)*sizeof(short)); |
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> |
for (r = -orad; r <= orad; r++) { |
| 176 |
> |
if (rcent+r < 0) continue; |
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> |
if (rcent+r >= nrows) break; |
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> |
gscan = greybar[(rcent+r)%obarsize]; |
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> |
for (c = -orad; c <= orad; c++) { |
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offs = ccent+c < 0 ? ncols : |
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ccent+c >= ncols ? -ncols : 0; |
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if (offs && !wrapfilt) |
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continue; |
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x = ringndx[c*c + r*r]; |
| 185 |
> |
if (x < 0) continue; |
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> |
ringsum[x] += gscan[ccent+c+offs]; |
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ringwt[x]++; |
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> |
} |
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> |
} |
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/* filter each subpixel */ |
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> |
for (y = ycent+1-ybrad; y <= ycent+ybrad; y++) { |
| 192 |
> |
if (y < 0) continue; |
| 193 |
> |
if (y >= yres) break; |
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> |
d = y_r < 1.0 ? y_r*y - (rcent+.5) : (double)(y - ycent); |
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> |
if (d < -0.5) continue; |
| 196 |
> |
if (d >= 0.5) break; |
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> |
for (x = xcent+1-xbrad; x <= xcent+xbrad; x++) { |
| 198 |
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offs = x < 0 ? xres : x >= xres ? -xres : 0; |
| 199 |
> |
if (offs && !wrapfilt) |
| 200 |
> |
continue; |
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> |
d = x_c < 1.0 ? x_c*x - (ccent+.5) : (double)(x - xcent); |
| 202 |
> |
if (d < -0.5) continue; |
| 203 |
> |
if (d >= 0.5) break; |
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> |
sumans(x, y, rcent, ccent, |
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> |
pickfilt((*ourbright)(scanin[y%barsize][x+offs]))); |
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> |
} |
| 207 |
> |
} |
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> |
} |
| 209 |
> |
|
| 210 |
> |
|
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> |
static double |
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> |
pickfilt( /* find filter multiplier for p0 */ |
| 213 |
> |
double p0 |
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> |
) |
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> |
{ |
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> |
double m = 1.0; |
| 217 |
> |
double t, num, denom, avg, wsum; |
| 218 |
> |
double mlimit[2]; |
| 219 |
> |
int ilimit = 4.0/TEPS; |
| 220 |
> |
int i; |
| 221 |
> |
/* iterative search for m */ |
| 222 |
> |
mlimit[0] = 1.0; mlimit[1] = orad/rad/CHECKRAD; |
| 223 |
> |
do { |
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> |
/* compute grey weighted average */ |
| 225 |
> |
i = RSCA*CHECKRAD*rad*m + .5; |
| 226 |
> |
if (i > orad) i = orad; |
| 227 |
> |
avg = wsum = 0.0; |
| 228 |
> |
while (i--) { |
| 229 |
> |
t = (i+.5)/(m*rad); |
| 230 |
> |
t = lookgauss(t*t); |
| 231 |
> |
avg += t*ringsum[i]; |
| 232 |
> |
wsum += t*ringwt[i]; |
| 233 |
> |
} |
| 234 |
> |
if (avg < 1e-20) /* zero inclusive average */ |
| 235 |
> |
return(1.0); |
| 236 |
> |
avg /= wsum; |
| 237 |
> |
/* check threshold */ |
| 238 |
> |
denom = m*m/gausstable[0] - p0/avg; |
| 239 |
> |
if (denom <= FTINY) { /* zero exclusive average */ |
| 240 |
> |
if (m >= mlimit[1]-REPS) |
| 241 |
> |
break; |
| 242 |
> |
m = mlimit[1]; |
| 243 |
> |
continue; |
| 244 |
> |
} |
| 245 |
> |
num = p0/avg - 1.0; |
| 246 |
> |
if (num < 0.0) num = -num; |
| 247 |
> |
t = num/denom; |
| 248 |
> |
if (t <= thresh) { |
| 249 |
> |
if (m <= mlimit[0]+REPS || (thresh-t)/thresh <= TEPS) |
| 250 |
> |
break; |
| 251 |
> |
} else { |
| 252 |
> |
if (m >= mlimit[1]-REPS || (t-thresh)/thresh <= TEPS) |
| 253 |
> |
break; |
| 254 |
> |
} |
| 255 |
> |
t = m; /* remember current m */ |
| 256 |
> |
/* next guesstimate */ |
| 257 |
> |
m = sqrt(gausstable[0]*(num/thresh + p0/avg)); |
| 258 |
> |
if (m < t) { /* bound it */ |
| 259 |
> |
if (m <= mlimit[0]+FTINY) |
| 260 |
> |
m = 0.5*(mlimit[0] + t); |
| 261 |
> |
mlimit[1] = t; |
| 262 |
> |
} else { |
| 263 |
> |
if (m >= mlimit[1]-FTINY) |
| 264 |
> |
m = 0.5*(mlimit[1] + t); |
| 265 |
> |
mlimit[0] = t; |
| 266 |
> |
} |
| 267 |
> |
} while (--ilimit > 0); |
| 268 |
> |
return(m); |
| 269 |
> |
} |
| 270 |
> |
|
| 271 |
> |
|
| 272 |
> |
static void |
| 273 |
> |
sumans( /* sum input pixel to output */ |
| 274 |
> |
int px, |
| 275 |
> |
int py, |
| 276 |
> |
int rcent, |
| 277 |
> |
int ccent, |
| 278 |
> |
double m |
| 279 |
> |
) |
| 280 |
> |
{ |
| 281 |
> |
double dy2, dx; |
| 282 |
> |
COLOR pval, ctmp; |
| 283 |
> |
int ksiz, r, offs; |
| 284 |
> |
double pc, pr, norm; |
| 285 |
> |
int i, c; |
| 286 |
> |
COLOR *scan; |
| 287 |
> |
/* |
| 288 |
> |
* This normalization method fails at the picture borders because |
| 289 |
> |
* a different number of input pixels contribute there. |
| 290 |
> |
*/ |
| 291 |
> |
scan = scanin[py%barsize] + (px < 0 ? xres : px >= xres ? -xres : 0); |
| 292 |
> |
copycolor(pval, scan[px]); |
| 293 |
> |
pc = x_c*(px+.5); |
| 294 |
> |
pr = y_r*(py+.5); |
| 295 |
> |
ksiz = CHECKRAD*m*rad + 1; |
| 296 |
> |
if (ksiz > orad) ksiz = orad; |
| 297 |
> |
/* compute normalization */ |
| 298 |
> |
norm = 0.0; |
| 299 |
> |
i = 0; |
| 300 |
> |
for (r = rcent-ksiz; r <= rcent+ksiz; r++) { |
| 301 |
> |
if (r < 0) continue; |
| 302 |
> |
if (r >= nrows) break; |
| 303 |
> |
dy2 = (pr - (r+.5))/(m*rad); |
| 304 |
> |
dy2 *= dy2; |
| 305 |
> |
for (c = ccent-ksiz; c <= ccent+ksiz; c++) { |
| 306 |
> |
if (!wrapfilt) { |
| 307 |
> |
if (c < 0) continue; |
| 308 |
> |
if (c >= ncols) break; |
| 309 |
> |
} |
| 310 |
> |
dx = (pc - (c+.5))/(m*rad); |
| 311 |
> |
norm += warr[i++] = lookgauss(dx*dx + dy2); |
| 312 |
> |
} |
| 313 |
> |
} |
| 314 |
> |
norm = 1.0/norm; |
| 315 |
> |
if (x_c < 1.0) norm *= x_c; |
| 316 |
> |
if (y_r < 1.0) norm *= y_r; |
| 317 |
> |
/* sum pixels */ |
| 318 |
> |
i = 0; |
| 319 |
> |
for (r = rcent-ksiz; r <= rcent+ksiz; r++) { |
| 320 |
> |
if (r < 0) continue; |
| 321 |
> |
if (r >= nrows) break; |
| 322 |
> |
scan = scoutbar[r%obarsize]; |
| 323 |
> |
for (c = ccent-ksiz; c <= ccent+ksiz; c++) { |
| 324 |
> |
offs = c < 0 ? ncols : c >= ncols ? -ncols : 0; |
| 325 |
> |
if ((offs != 0) & !wrapfilt) |
| 326 |
> |
continue; |
| 327 |
> |
copycolor(ctmp, pval); |
| 328 |
> |
dx = norm*warr[i++]; |
| 329 |
> |
scalecolor(ctmp, dx); |
| 330 |
> |
addcolor(scan[c+offs], ctmp); |
| 331 |
> |
} |
| 332 |
> |
} |
| 333 |
|
} |
