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#ifndef lint |
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static const char RCSid[] = "$Id: pcond3.c,v 3.18 2020/06/27 03:37:24 greg Exp $"; |
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#endif |
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/* |
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* Routines for computing and applying brightness mapping. |
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*/ |
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|
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#include <string.h> |
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|
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#include "pcond.h" |
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#include "random.h" |
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|
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|
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#define CVRATIO 0.025 /* fraction of samples allowed > env. */ |
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|
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#define LN_10 2.30258509299404568402 |
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#define exp10(x) exp(LN_10*(x)) |
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|
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double modhist[HISTRES]; /* modified histogram */ |
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double mhistot; /* modified histogram total */ |
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double cumf[HISTRES+1]; /* cumulative distribution function */ |
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|
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static double centprob(int x, int y); |
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static void mkcumf(void); |
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static double cf(double b); |
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static double BLw(double Lw); |
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static float *getlumsamp(int n); |
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#if ADJ_VEIL |
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static void mkcrfimage(void); |
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#endif |
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|
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|
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|
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void |
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getfixations( /* load fixation history list */ |
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FILE *fp |
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) |
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{ |
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#define FIXHUNK 128 |
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RESOLU fvres; |
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int pos[2]; |
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int px, py, i; |
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/* initialize our resolution struct */ |
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if ((fvres.rt=inpres.rt)&YMAJOR) { |
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fvres.xr = fvxr; |
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fvres.yr = fvyr; |
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} else { |
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fvres.xr = fvyr; |
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fvres.yr = fvxr; |
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} |
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/* read each picture position */ |
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while (fscanf(fp, "%d %d", &pos[0], &pos[1]) == 2) { |
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/* convert to closest index in foveal image */ |
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loc2pix(pos, &fvres, |
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(pos[0]+.5)/inpres.xr, (pos[1]+.5)/inpres.yr); |
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/* include nine neighborhood samples */ |
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for (px = pos[0]-1; px <= pos[0]+1; px++) { |
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if (px < 0 || px >= fvxr) |
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continue; |
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for (py = pos[1]-1; py <= pos[1]+1; py++) { |
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if (py < 0 || py >= fvyr) |
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continue; |
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for (i = nfixations; i-- > 0; ) |
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if (fixlst[i][0] == px && |
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fixlst[i][1] == py) |
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break; |
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if (i >= 0) |
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continue; /* already there */ |
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if (nfixations % FIXHUNK == 0) { |
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if (nfixations) |
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fixlst = (short (*)[2]) |
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realloc((void *)fixlst, |
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(nfixations+FIXHUNK)* |
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2*sizeof(short)); |
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else |
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fixlst = (short (*)[2])malloc( |
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FIXHUNK*2*sizeof(short) |
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); |
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if (fixlst == NULL) |
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syserror("malloc"); |
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} |
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fixlst[nfixations][0] = px; |
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fixlst[nfixations][1] = py; |
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nfixations++; |
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} |
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} |
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} |
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if (!feof(fp)) { |
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fprintf(stderr, "%s: format error reading fixation data\n", |
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progname); |
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exit(1); |
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} |
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#undef FIXHUNK |
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} |
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|
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|
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void |
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gethisto( /* load precomputed luminance histogram */ |
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FILE *fp |
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) |
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{ |
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double histo[MAXPREHIST]; |
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double histart, histep; |
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double b, lastb, w; |
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int n; |
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int i; |
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/* load data */ |
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for (i = 0; i < MAXPREHIST && |
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fscanf(fp, "%lf %lf", &b, &histo[i]) == 2; i++) { |
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if (i > 1 && fabs(b - lastb - histep) > .001) { |
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fprintf(stderr, |
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"%s: uneven step size in histogram data\n", |
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progname); |
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exit(1); |
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} |
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if (i == 1) |
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if ((histep = b - (histart = lastb)) <= FTINY) { |
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fprintf(stderr, |
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"%s: illegal step in histogram data\n", |
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progname); |
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exit(1); |
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} |
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lastb = b; |
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} |
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if (i < 2 || !feof(fp)) { |
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fprintf(stderr, |
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"%s: format/length error loading histogram (log10L %f at %d)\n", |
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progname, b, i); |
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exit(1); |
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} |
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n = i; |
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histart *= LN_10; |
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histep *= LN_10; |
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/* find extrema */ |
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for (i = 0; i < n && histo[i] <= FTINY; i++) |
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; |
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bwmin = histart + (i-.001)*histep; |
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for (i = n; i-- && histo[i] <= FTINY; ) |
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; |
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bwmax = histart + (i+1.001)*histep; |
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if (bwmax > Bl(LMAX)) |
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bwmax = Bl(LMAX); |
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if (bwmin < Bl(LMIN)) |
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bwmin = Bl(LMIN); |
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else /* duplicate bottom bin */ |
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bwmin = bwmax - (bwmax-bwmin)*HISTRES/(HISTRES-1); |
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/* convert histogram */ |
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bwavg = 0.; histot = 0.; |
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for (i = 0; i < HISTRES; i++) |
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bwhist[i] = 0.; |
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for (i = 0, b = histart; i < n; i++, b += histep) { |
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if (b < bwmin+FTINY) continue; |
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if (b >= bwmax-FTINY) break; |
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w = histo[i]; |
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bwavg += w*b; |
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bwhist[bwhi(b)] += w; |
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histot += w; |
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} |
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bwavg /= histot; |
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if (bwmin > Bl(LMIN)+FTINY) { /* add false samples at bottom */ |
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bwhist[1] *= 0.5; |
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bwhist[0] += bwhist[1]; |
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} |
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} |
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|
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|
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static double |
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centprob( /* center-weighting probability function */ |
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int x, |
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int y |
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) |
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{ |
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double xr, yr, p; |
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/* paraboloid, 0 at 90 degrees from center */ |
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xr = (x - .5*(fvxr-1))/90.; /* 180 degree fisheye has fv?r == 90 */ |
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yr = (y - .5*(fvyr-1))/90.; |
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p = 1. - xr*xr - yr*yr; |
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return(p < 0. ? 0. : p); |
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} |
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|
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|
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static float * |
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getlumsamp(int n) /* get set of random point sample luminances */ |
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{ |
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float *ls = (float *)malloc(n*sizeof(float)); |
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COLR *cscan = (COLR *)malloc(scanlen(&inpres)*sizeof(COLR)); |
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long startpos = ftell(infp); |
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long npleft = (long)inpres.xr*inpres.yr; |
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int x; |
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|
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if ((ls == NULL) | (cscan == NULL)) |
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syserror("malloc"); |
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x = 0; /* read/convert samples */ |
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while (n > 0) { |
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COLOR col; |
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int sv = 0; |
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double rval, cumprob = 0; |
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|
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if (x <= 0 && freadcolrs(cscan, x=scanlen(&inpres), infp) < 0) { |
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fprintf(stderr, "%s: %s: scanline read error\n", |
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progname, infn); |
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exit(1); |
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} |
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rval = frandom(); /* random distance to next sample */ |
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while ((cumprob += (1.-cumprob)*n/(npleft-sv)) < rval) |
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sv++; |
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if (x < ++sv) { /* out of pixels in this scanline */ |
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npleft -= x; |
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x = 0; |
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continue; |
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} |
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x -= sv; |
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colr_color(col, cscan[x]); |
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ls[--n] = plum(col); |
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npleft -= sv; |
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} |
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free(cscan); /* clean up and reset file pointer */ |
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if (fseek(infp, startpos, SEEK_SET) < 0) |
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syserror("fseek"); |
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return(ls); |
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} |
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|
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|
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void |
225 |
comphist(void) /* create foveal sampling histogram */ |
226 |
{ |
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double l, b, w, lwmin, lwmax; |
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float *lumsamp; |
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int nlumsamp; |
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int x, y; |
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/* check for precalculated histogram */ |
232 |
if (what2do&DO_PREHIST) |
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return; |
234 |
lwmin = 1e10; /* find extrema */ |
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lwmax = 0.; |
236 |
for (y = 0; y < fvyr; y++) |
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for (x = 0; x < fvxr; x++) { |
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l = plum(fovscan(y)[x]); |
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if (l < lwmin) lwmin = l; |
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if (l > lwmax) lwmax = l; |
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} |
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/* sample luminance pixels */ |
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nlumsamp = fvxr*fvyr*16; |
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if (nlumsamp > inpres.xr*inpres.yr) |
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nlumsamp = inpres.xr*inpres.yr; |
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lumsamp = getlumsamp(nlumsamp); |
247 |
for (x = nlumsamp; x--; ) { |
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l = lumsamp[x]; |
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if (l < lwmin) lwmin = l; |
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if (l > lwmax) lwmax = l; |
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} |
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lwmax *= 1.01; |
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if (lwmax > LMAX) |
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lwmax = LMAX; |
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bwmax = Bl(lwmax); |
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if (lwmin < LMIN) { |
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lwmin = LMIN; |
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bwmin = Bl(LMIN); |
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} else { /* duplicate bottom bin */ |
260 |
bwmin = bwmax - (bwmax-Bl(lwmin))*HISTRES/(HISTRES-1); |
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lwmin = Lb(bwmin); |
262 |
} |
263 |
/* (re)compute histogram */ |
264 |
bwavg = 0.; |
265 |
histot = 0.; |
266 |
memset(bwhist, 0, sizeof(bwhist)); |
267 |
/* global average */ |
268 |
if (!(what2do&DO_FIXHIST) || fixfrac < 1.-FTINY) { |
269 |
for (y = 0; y < fvyr; y++) |
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for (x = 0; x < fvxr; x++) { |
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l = plum(fovscan(y)[x]); |
272 |
if (l < lwmin+FTINY) continue; |
273 |
if (l >= lwmax-FTINY) continue; |
274 |
b = Bl(l); |
275 |
w = what2do&DO_CWEIGHT ? centprob(x,y) : 1.; |
276 |
bwavg += w*b; |
277 |
bwhist[bwhi(b)] += w; |
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histot += w; |
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} |
280 |
/* weight for point luminances */ |
281 |
w = 1. * histot / nlumsamp; |
282 |
for (x = nlumsamp; x--; ) { |
283 |
l = lumsamp[x]; |
284 |
if (l < lwmin+FTINY) continue; |
285 |
if (l >= lwmax-FTINY) continue; |
286 |
b = Bl(l); |
287 |
bwavg += w*b; |
288 |
bwhist[bwhi(b)] += w; |
289 |
histot += w; |
290 |
} |
291 |
} |
292 |
/* average fixation points */ |
293 |
if (what2do&DO_FIXHIST && nfixations > 0) { |
294 |
if (histot > FTINY) |
295 |
w = fixfrac/(1.-fixfrac)*histot/nfixations; |
296 |
else |
297 |
w = 1.; |
298 |
for (x = 0; x < nfixations; x++) { |
299 |
l = plum(fovscan(fixlst[x][1])[fixlst[x][0]]); |
300 |
if (l < lwmin+FTINY) continue; |
301 |
if (l >= lwmax-FTINY) continue; |
302 |
b = Bl(l); |
303 |
bwavg += w*b; |
304 |
bwhist[bwhi(b)] += w; |
305 |
histot += w; |
306 |
} |
307 |
} |
308 |
bwavg /= histot; |
309 |
if (lwmin > LMIN+FTINY) { /* add false samples at bottom */ |
310 |
bwhist[1] *= 0.5; |
311 |
bwhist[0] += bwhist[1]; |
312 |
} |
313 |
free(lumsamp); |
314 |
} |
315 |
|
316 |
|
317 |
static void |
318 |
mkcumf(void) /* make cumulative distribution function */ |
319 |
{ |
320 |
int i; |
321 |
double sum; |
322 |
|
323 |
mhistot = 0.; /* compute modified total */ |
324 |
for (i = 0; i < HISTRES; i++) |
325 |
mhistot += modhist[i]; |
326 |
|
327 |
sum = 0.; /* compute cumulative function */ |
328 |
for (i = 0; i < HISTRES; i++) { |
329 |
cumf[i] = sum/mhistot; |
330 |
sum += modhist[i]; |
331 |
} |
332 |
cumf[HISTRES] = 1.; |
333 |
} |
334 |
|
335 |
|
336 |
static double |
337 |
cf( /* return cumulative function at b */ |
338 |
double b |
339 |
) |
340 |
{ |
341 |
double x; |
342 |
int i; |
343 |
|
344 |
i = x = HISTRES*(b - bwmin)/(bwmax - bwmin); |
345 |
x -= (double)i; |
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return(cumf[i]*(1.-x) + cumf[i+1]*x); |
347 |
} |
348 |
|
349 |
|
350 |
static double |
351 |
BLw( /* map world luminance to display brightness */ |
352 |
double Lw |
353 |
) |
354 |
{ |
355 |
double b; |
356 |
|
357 |
if (Lw <= LMIN || (b = Bl(Lw)) <= bwmin+FTINY) |
358 |
return(Bldmin); |
359 |
if (b >= bwmax-FTINY) |
360 |
return(Bldmax); |
361 |
return(Bldmin + cf(b)*(Bldmax-Bldmin)); |
362 |
} |
363 |
|
364 |
|
365 |
double |
366 |
htcontrs( /* human threshold contrast sensitivity, dL(La) */ |
367 |
double La |
368 |
) |
369 |
{ |
370 |
double l10La, l10dL; |
371 |
/* formula taken from Ferwerda et al. [SG96] */ |
372 |
if (La < 1.148e-4) |
373 |
return(1.38e-3); |
374 |
l10La = log10(La); |
375 |
if (l10La < -1.44) /* rod response regime */ |
376 |
l10dL = pow(.405*l10La + 1.6, 2.18) - 2.86; |
377 |
else if (l10La < -.0184) |
378 |
l10dL = l10La - .395; |
379 |
else if (l10La < 1.9) /* cone response regime */ |
380 |
l10dL = pow(.249*l10La + .65, 2.7) - .72; |
381 |
else |
382 |
l10dL = l10La - 1.255; |
383 |
|
384 |
return(exp10(l10dL)); |
385 |
} |
386 |
|
387 |
|
388 |
double |
389 |
clampf( /* histogram clamping function */ |
390 |
double Lw |
391 |
) |
392 |
{ |
393 |
double bLw, ratio; |
394 |
|
395 |
bLw = BLw(Lw); /* apply current brightness map */ |
396 |
ratio = what2do&DO_HSENS ? htcontrs(Lb(bLw))/htcontrs(Lw) : Lb(bLw)/Lw; |
397 |
return(ratio/(Lb1(bLw)*(Bldmax-Bldmin)*Bl1(Lw))); |
398 |
} |
399 |
|
400 |
double |
401 |
crfactor( /* contrast reduction factor */ |
402 |
double Lw |
403 |
) |
404 |
{ |
405 |
int i = HISTRES*(Bl(Lw) - bwmin)/(bwmax - bwmin); |
406 |
double bLw, ratio, Tdb; |
407 |
|
408 |
if (i <= 0) |
409 |
return(1.0); |
410 |
if (i >= HISTRES) |
411 |
return(1.0); |
412 |
bLw = BLw(Lw); |
413 |
ratio = what2do&DO_HSENS ? htcontrs(Lb(bLw))/htcontrs(Lw) : Lb(bLw)/Lw; |
414 |
Tdb = mhistot * (bwmax - bwmin) / HISTRES; |
415 |
return(modhist[i]*Lb1(bLw)*(Bldmax-Bldmin)*Bl1(Lw)/(Tdb*ratio)); |
416 |
} |
417 |
|
418 |
|
419 |
#if ADJ_VEIL |
420 |
static void |
421 |
mkcrfimage(void) /* compute contrast reduction factor image */ |
422 |
{ |
423 |
int i; |
424 |
float *crfptr; |
425 |
COLOR *fovptr; |
426 |
|
427 |
if (crfimg == NULL) |
428 |
crfimg = (float *)malloc(fvxr*fvyr*sizeof(float)); |
429 |
if (crfimg == NULL) |
430 |
syserror("malloc"); |
431 |
crfptr = crfimg; |
432 |
fovptr = fovimg; |
433 |
for (i = fvxr*fvyr; i--; crfptr++, fovptr++) |
434 |
crfptr[0] = crfactor(plum(fovptr[0])); |
435 |
} |
436 |
#endif |
437 |
|
438 |
|
439 |
int |
440 |
mkbrmap(void) /* make dynamic range map */ |
441 |
{ |
442 |
double Tdb, b, s; |
443 |
double ceiling, trimmings; |
444 |
int i; |
445 |
/* copy initial histogram */ |
446 |
memcpy((void *)modhist, (void *)bwhist, sizeof(modhist)); |
447 |
s = (bwmax - bwmin)/HISTRES; /* s is delta b */ |
448 |
/* loop until satisfactory */ |
449 |
do { |
450 |
mkcumf(); /* sync brightness mapping */ |
451 |
if (mhistot <= histot*CVRATIO) |
452 |
return(-1); /* no compression needed! */ |
453 |
Tdb = mhistot * s; |
454 |
trimmings = 0.; /* clip to envelope */ |
455 |
for (i = 0, b = bwmin + .5*s; i < HISTRES; i++, b += s) { |
456 |
ceiling = Tdb*clampf(Lb(b)); |
457 |
if (modhist[i] > ceiling) { |
458 |
trimmings += modhist[i] - ceiling; |
459 |
modhist[i] = ceiling; |
460 |
} |
461 |
} |
462 |
} while (trimmings > mhistot*CVRATIO); |
463 |
|
464 |
#if ADJ_VEIL |
465 |
mkcrfimage(); /* contrast reduction image */ |
466 |
#endif |
467 |
|
468 |
return(0); /* we got it */ |
469 |
} |
470 |
|
471 |
|
472 |
void |
473 |
scotscan( /* apply scotopic color sensitivity loss */ |
474 |
COLOR *scan, |
475 |
int xres |
476 |
) |
477 |
{ |
478 |
COLOR ctmp; |
479 |
double incolor, b, Lw; |
480 |
int i; |
481 |
|
482 |
for (i = 0; i < xres; i++) { |
483 |
Lw = plum(scan[i]); |
484 |
if (Lw >= TopMesopic) |
485 |
incolor = 1.; |
486 |
else if (Lw <= BotMesopic) |
487 |
incolor = 0.; |
488 |
else |
489 |
incolor = (Lw - BotMesopic) / |
490 |
(TopMesopic - BotMesopic); |
491 |
if (incolor < 1.-FTINY) { |
492 |
b = (1.-incolor)*slum(scan[i])*inpexp/SWNORM; |
493 |
if (lumf == rgblum) b /= WHTEFFICACY; |
494 |
setcolor(ctmp, b, b, b); |
495 |
if (incolor <= FTINY) |
496 |
setcolor(scan[i], 0., 0., 0.); |
497 |
else |
498 |
scalecolor(scan[i], incolor); |
499 |
addcolor(scan[i], ctmp); |
500 |
} |
501 |
} |
502 |
} |
503 |
|
504 |
|
505 |
void |
506 |
mapscan( /* apply tone mapping operator to scanline */ |
507 |
COLOR *scan, |
508 |
int xres |
509 |
) |
510 |
{ |
511 |
double mult, Lw, b; |
512 |
int x; |
513 |
|
514 |
for (x = 0; x < xres; x++) { |
515 |
Lw = plum(scan[x]); |
516 |
if (Lw < LMIN) { |
517 |
setcolor(scan[x], 0., 0., 0.); |
518 |
continue; |
519 |
} |
520 |
b = BLw(Lw); /* apply brightness mapping */ |
521 |
mult = (Lb(b) - ldmin)/(ldmax - ldmin)/(Lw*inpexp); |
522 |
if (lumf == rgblum) mult *= WHTEFFICACY; |
523 |
scalecolor(scan[x], mult); |
524 |
} |
525 |
} |
526 |
|
527 |
|
528 |
void |
529 |
putmapping( /* put out mapping function */ |
530 |
FILE *fp |
531 |
) |
532 |
{ |
533 |
double b, s; |
534 |
int i; |
535 |
double wlum, sf, dlum; |
536 |
|
537 |
sf = scalef*inpexp; |
538 |
if (lumf == cielum) sf *= WHTEFFICACY; |
539 |
s = (bwmax - bwmin)/HISTRES; |
540 |
for (i = 0, b = bwmin + .5*s; i < HISTRES; i++, b += s) { |
541 |
wlum = Lb(b); |
542 |
if (what2do&DO_LINEAR) { |
543 |
dlum = sf*wlum; |
544 |
if (dlum > ldmax) dlum = ldmax; |
545 |
else if (dlum < ldmin) dlum = ldmin; |
546 |
fprintf(fp, "%e %e\n", wlum, dlum); |
547 |
} else |
548 |
fprintf(fp, "%e %e\n", wlum, Lb(BLw(wlum))); |
549 |
} |
550 |
} |