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/* Copyright (c) 1994 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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* Neural-Net quantization algorithm based on work of Anthony Dekker |
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*/ |
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#include "standard.h" |
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#include "copyright.h" |
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#include "color.h" |
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#include <string.h> |
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#include "standard.h" |
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#include "color.h" |
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#include "random.h" |
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#include "clrtab.h" |
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#ifdef COMPAT_MODE |
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#define neu_init new_histo |
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#define setskip(sp,n) ((sp)[0]=(n)>>16,(sp)[1]=((n)>>8)&255,(sp)[2]=(n)&255) |
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static void initnet(void); |
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static void inxbuild(void); |
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static int inxsearch(int b, int g, int r); |
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static int contest(int b, int g, int r); |
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static void altersingle(int alpha, int i, int b, int g, int r); |
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static void alterneigh(int rad, int i, int b, int g, int r); |
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static void learn(void); |
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static void unbiasnet(void); |
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static void cpyclrtab(void); |
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neu_init(npixels) /* initialize our sample array */ |
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long npixels; |
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extern int |
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neu_init( /* initialize our sample array */ |
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long npixels |
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) |
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{ |
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register int nsleft; |
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register long sv; |
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} |
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neu_pixel(col) /* add pixel to our samples */ |
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register BYTE col[]; |
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extern void |
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neu_pixel( /* add pixel to our samples */ |
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register BYTE col[] |
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) |
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{ |
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if (!skipcount--) { |
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skipcount = nskip(cursamp); |
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} |
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neu_colrs(cs, n) /* add a scanline to our samples */ |
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register COLR *cs; |
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register int n; |
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extern void |
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neu_colrs( /* add a scanline to our samples */ |
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register COLR *cs, |
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register int n |
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) |
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{ |
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while (n > skipcount) { |
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cs += skipcount; |
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} |
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neu_clrtab(ncolors) /* make new color table using ncolors */ |
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int ncolors; |
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extern int |
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neu_clrtab( /* make new color table using ncolors */ |
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int ncolors |
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) |
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{ |
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clrtabsiz = ncolors; |
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if (clrtabsiz > 256) clrtabsiz = 256; |
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cpyclrtab(); |
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inxbuild(); |
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/* we're done with our samples */ |
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free((char *)thesamples); |
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free((void *)thesamples); |
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/* reset dithering function */ |
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neu_dith_colrs((BYTE *)NULL, (COLR *)NULL, 0); |
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/* return new color table size */ |
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} |
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int |
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neu_map_pixel(col) /* get pixel for color */ |
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register BYTE col[]; |
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extern int |
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neu_map_pixel( /* get pixel for color */ |
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register BYTE col[] |
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) |
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{ |
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return(inxsearch(col[BLU],col[GRN],col[RED])); |
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} |
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neu_map_colrs(bs, cs, n) /* convert a scanline to color index values */ |
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register BYTE *bs; |
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register COLR *cs; |
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register int n; |
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extern void |
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neu_map_colrs( /* convert a scanline to color index values */ |
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register BYTE *bs, |
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register COLR *cs, |
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register int n |
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) |
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{ |
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while (n-- > 0) { |
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*bs++ = inxsearch(cs[0][BLU],cs[0][GRN],cs[0][RED]); |
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} |
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neu_dith_colrs(bs, cs, n) /* convert scanline to dithered index values */ |
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register BYTE *bs; |
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register COLR *cs; |
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int n; |
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extern void |
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neu_dith_colrs( /* convert scanline to dithered index values */ |
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register BYTE *bs, |
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register COLR *cs, |
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int n |
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) |
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{ |
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static short (*cerr)[3] = NULL; |
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static int N = 0; |
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if (n != N) { /* get error propogation array */ |
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if (N) { |
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free((char *)cerr); |
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free((void *)cerr); |
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cerr = NULL; |
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} |
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if (n) |
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return; |
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} |
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N = n; |
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bzero((char *)cerr, 3*N*sizeof(short)); |
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memset((char *)cerr, '\0', 3*N*sizeof(short)); |
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} |
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err[0] = err[1] = err[2] = 0; |
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for (x = 0; x < n; x++) { |
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#define true 1 |
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/* network defs */ |
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#define netsize 256 /* number of colours - can change this */ |
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#define netsize clrtabsiz /* number of colours - can change this */ |
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#define maxnetpos (netsize-1) |
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#define netbiasshift 4 /* bias for colour values */ |
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#define ncycles 100 /* no. of learning cycles */ |
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#define betagamma (intbias<<(gammashift-betashift)) |
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/* defs for decreasing radius factor */ |
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#define initrad (netsize>>3) /* for 256 cols, radius starts */ |
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#define initrad (256>>3) /* for 256 cols, radius starts */ |
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#define radiusbiasshift 6 /* at 32.0 biased by 6 bits */ |
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#define radiusbias (((int) 1)<<radiusbiasshift) |
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#define initradius (initrad*radiusbias) /* and decreases by a */ |
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#define prime4 503 |
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typedef int pixel[4]; /* BGRc */ |
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pixel network[netsize]; |
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pixel network[256]; |
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int netindex[256]; /* for network lookup - really 256 */ |
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int bias [netsize]; /* bias and freq arrays for learning */ |
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int freq [netsize]; |
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int bias [256]; /* bias and freq arrays for learning */ |
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int freq [256]; |
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int radpower[initrad]; /* radpower for precomputation */ |
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/* initialise network in range (0,0,0) to (255,255,255) */ |
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initnet() |
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static void |
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initnet(void) |
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{ |
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register int i; |
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register int *p; |
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for (i=0; i<clrtabsiz; i++) { |
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for (i=0; i<netsize; i++) { |
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p = network[i]; |
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p[0] = p[1] = p[2] = (i << (netbiasshift+8))/clrtabsiz; |
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freq[i] = intbias/clrtabsiz; /* 1/clrtabsiz */ |
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p[0] = p[1] = p[2] = (i << (netbiasshift+8))/netsize; |
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freq[i] = intbias/netsize; /* 1/netsize */ |
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bias[i] = 0; |
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} |
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} |
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/* do after unbias - insertion sort of network and build netindex[0..255] */ |
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inxbuild() |
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static void |
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inxbuild(void) |
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{ |
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register int i,j,smallpos,smallval; |
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register int *p,*q; |
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previouscol = 0; |
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startpos = 0; |
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for (i=0; i<clrtabsiz; i++) { |
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for (i=0; i<netsize; i++) { |
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p = network[i]; |
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smallpos = i; |
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smallval = p[1]; /* index on g */ |
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/* find smallest in i..clrtabsiz-1 */ |
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for (j=i+1; j<clrtabsiz; j++) { |
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/* find smallest in i..netsize-1 */ |
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for (j=i+1; j<netsize; j++) { |
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q = network[j]; |
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if (q[1] < smallval) { /* index on g */ |
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smallpos = j; |
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} |
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int inxsearch(b,g,r) /* accepts real BGR values after net is unbiased */ |
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register int b,g,r; |
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static int |
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inxsearch( /* accepts real BGR values after net is unbiased */ |
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register int b, |
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register int g, |
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register int r |
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) |
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{ |
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register int i,j,dist,a,bestd; |
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register int *p; |
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i = netindex[g]; /* index on g */ |
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j = i-1; /* start at netindex[g] and work outwards */ |
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while ((i<clrtabsiz) || (j>=0)) { |
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if (i<clrtabsiz) { |
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while ((i<netsize) || (j>=0)) { |
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if (i<netsize) { |
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p = network[i]; |
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dist = p[1] - g; /* inx key */ |
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if (dist >= bestd) i = clrtabsiz; /* stop iter */ |
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if (dist >= bestd) i = netsize; /* stop iter */ |
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else { |
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i++; |
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if (dist<0) dist = -dist; |
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/* finds closest neuron (min dist) and updates freq */ |
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/* finds best neuron (min dist-bias) and returns position */ |
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/* for frequently chosen neurons, freq[i] is high and bias[i] is negative */ |
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/* bias[i] = gamma*((1/clrtabsiz)-freq[i]) */ |
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/* bias[i] = gamma*((1/netsize)-freq[i]) */ |
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int contest(b,g,r) /* accepts biased BGR values */ |
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register int b,g,r; |
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static int |
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contest( /* accepts biased BGR values */ |
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register int b, |
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register int g, |
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register int r |
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) |
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{ |
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register int i,dist,a,biasdist,betafreq; |
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int bestpos,bestbiaspos,bestd,bestbiasd; |
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p = bias; |
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f = freq; |
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for (i=0; i<clrtabsiz; i++) { |
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for (i=0; i<netsize; i++) { |
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n = network[i]; |
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dist = n[0] - b; if (dist<0) dist = -dist; |
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a = n[1] - g; if (a<0) a = -a; |
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/* move neuron i towards (b,g,r) by factor alpha */ |
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altersingle(alpha,i,b,g,r) /* accepts biased BGR values */ |
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register int alpha,i,b,g,r; |
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static void |
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altersingle( /* accepts biased BGR values */ |
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register int alpha, |
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register int i, |
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register int b, |
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register int g, |
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register int r |
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) |
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{ |
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register int *n; |
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/* move neurons adjacent to i towards (b,g,r) by factor */ |
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/* alpha*(1-((i-j)^2/[r]^2)) precomputed as radpower[|i-j|]*/ |
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alterneigh(rad,i,b,g,r) /* accents biased BGR values */ |
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int rad,i; |
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register int b,g,r; |
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static void |
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alterneigh( /* accents biased BGR values */ |
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int rad, |
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int i, |
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register int b, |
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register int g, |
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register int r |
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) |
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{ |
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register int j,k,lo,hi,a; |
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register int *p, *q; |
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lo = i-rad; if (lo<-1) lo= -1; |
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hi = i+rad; if (hi>clrtabsiz) hi=clrtabsiz; |
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hi = i+rad; if (hi>netsize) hi=netsize; |
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j = i+1; |
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k = i-1; |
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} |
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learn() |
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static void |
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learn(void) |
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{ |
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register int i,j,b,g,r; |
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int radius,rad,alpha,step,delta,samplepixels; |
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/* which can then be used for colour map */ |
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/* and record position i to prepare for sort */ |
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unbiasnet() |
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static void |
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unbiasnet(void) |
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{ |
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int i,j; |
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for (i=0; i<clrtabsiz; i++) { |
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for (i=0; i<netsize; i++) { |
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for (j=0; j<3; j++) |
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network[i][j] >>= netbiasshift; |
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network[i][3] = i; /* record colour no */ |
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/* Don't do this until the network has been unbiased (GW) */ |
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static |
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cpyclrtab() |
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static void |
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cpyclrtab(void) |
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{ |
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register int i,j,k; |
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for (j=0; j<clrtabsiz; j++) { |
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for (j=0; j<netsize; j++) { |
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k = network[j][3]; |
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for (i = 0; i < 3; i++) |
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clrtab[k][i] = network[j][2-i]; |