src/px/pcond3.c

#ifndef lint
static const char       RCSid[] = "$Id: pcond3.c,v 3.14 2003/06/30 14:59:12 schorsch Exp $";
#endif
/*
 * Routines for computing and applying brightness mapping.
 */

#include <string.h>

#include "pcond.h"


#define CVRATIO         0.025           /* fraction of samples allowed > env. */

#define LN_10           2.30258509299404568402
#define exp10(x)        exp(LN_10*(x))

double  modhist[HISTRES];               /* modified histogram */
double  mhistot;                        /* modified histogram total */
double  cumf[HISTRES+1];                /* cumulative distribution function */

static double centprob(int      x, int  y);
static void mkcumf(void);
static double cf(double b);
static double BLw(double        Lw);
#if ADJ_VEIL
static void mkcrfimage(void);
#endif


extern void
getfixations(           /* load fixation history list */
FILE    *fp
)
{
#define FIXHUNK         128
        RESOLU  fvres;
        int     pos[2];
        register int    px, py, i;
                                /* initialize our resolution struct */
        if ((fvres.rt=inpres.rt)&YMAJOR) {
                fvres.xr = fvxr;
                fvres.yr = fvyr;
        } else {
                fvres.xr = fvyr;
                fvres.yr = fvxr;
        }
                                /* read each picture position */
        while (fscanf(fp, "%d %d", &pos[0], &pos[1]) == 2) {
                                /* convert to closest index in foveal image */
                loc2pix(pos, &fvres,
                                (pos[0]+.5)/inpres.xr, (pos[1]+.5)/inpres.yr);
                                /* include nine neighborhood samples */
                for (px = pos[0]-1; px <= pos[0]+1; px++) {
                        if (px < 0 || px >= fvxr)
                                continue;
                        for (py = pos[1]-1; py <= pos[1]+1; py++) {
                                if (py < 0 || py >= fvyr)
                                        continue;
                                for (i = nfixations; i-- > 0; )
                                        if (fixlst[i][0] == px &&
                                                        fixlst[i][1] == py)
                                                break;
                                if (i >= 0)
                                        continue;       /* already there */
                                if (nfixations % FIXHUNK == 0) {
                                        if (nfixations)
                                                fixlst = (short (*)[2])
                                                        realloc((void *)fixlst,
                                                        (nfixations+FIXHUNK)*
                                                        2*sizeof(short));
                                        else
                                                fixlst = (short (*)[2])malloc(
                                                        FIXHUNK*2*sizeof(short)
                                                        );
                                        if (fixlst == NULL)
                                                syserror("malloc");
                                }
                                fixlst[nfixations][0] = px;
                                fixlst[nfixations][1] = py;
                                nfixations++;
                        }
                }
        }
        if (!feof(fp)) {
                fprintf(stderr, "%s: format error reading fixation data\n",
                                progname);
                exit(1);
        }
#undef  FIXHUNK
}


extern void
gethisto(                       /* load precomputed luminance histogram */
        FILE    *fp
)
{
        double  histo[MAXPREHIST];
        double  histart, histep;
        double  b, lastb, w;
        int     n;
        register int    i;
                                        /* load data */
        for (i = 0; i < MAXPREHIST &&
                        fscanf(fp, "%lf %lf", &b, &histo[i]) == 2; i++) {
                if (i > 1 && fabs(b - lastb - histep) > .001) {
                        fprintf(stderr,
                                "%s: uneven step size in histogram data\n",
                                        progname);
                        exit(1);
                }
                if (i == 1)
                        if ((histep = b - (histart = lastb)) <= FTINY) {
                                fprintf(stderr,
                                        "%s: illegal step in histogram data\n",
                                                progname);
                                exit(1);
                        }
                lastb = b;
        }
        if (i < 2 || !feof(fp)) {
                fprintf(stderr,
                "%s: format/length error loading histogram (log10L %f at %d)\n",
                                progname, b, i);
                exit(1);
        }
        n = i;
        histart *= LN_10;
        histep *= LN_10;
                                        /* find extrema */
        for (i = 0; i < n && histo[i] <= FTINY; i++)
                ;
        bwmin = histart + (i-.001)*histep;
        for (i = n; i-- && histo[i] <= FTINY; )
                ;
        bwmax = histart + (i+1.001)*histep;
        if (bwmax > Bl(LMAX))
                bwmax = Bl(LMAX);
        if (bwmin < Bl(LMIN))
                bwmin = Bl(LMIN);
        else                            /* duplicate bottom bin */
                bwmin = bwmax - (bwmax-bwmin)*HISTRES/(HISTRES-1);
                                        /* convert histogram */
        bwavg = 0.; histot = 0.;
        for (i = 0; i < HISTRES; i++)
                bwhist[i] = 0.;
        for (i = 0, b = histart; i < n; i++, b += histep) {
                if (b < bwmin+FTINY) continue;
                if (b >= bwmax-FTINY) break;
                w = histo[i];
                bwavg += w*b;
                bwhist[bwhi(b)] += w;
                histot += w;
        }
        bwavg /= histot;
        if (bwmin > Bl(LMIN)+FTINY) {   /* add false samples at bottom */
                bwhist[1] *= 0.5;
                bwhist[0] += bwhist[1];
        }
}


static double
centprob(                       /* center-weighting probability function */
        int     x,
        int     y
)
{
        double  xr, yr, p;
                                /* paraboloid, 0 at 90 degrees from center */
        xr = (x - .5*(fvxr-1))/90.;     /* 180 degree fisheye has fv?r == 90 */
        yr = (y - .5*(fvyr-1))/90.;
        p = 1. - xr*xr - yr*yr;
        return(p < 0. ? 0. : p);
}


extern void
comphist(void)                  /* create foveal sampling histogram */
{
        double  l, b, w, lwmin, lwmax;
        register int    x, y;
                                        /* check for precalculated histogram */
        if (what2do&DO_PREHIST)
                return;
        lwmin = 1e10;                   /* find extrema */
        lwmax = 0.;
        for (y = 0; y < fvyr; y++)
                for (x = 0; x < fvxr; x++) {
                        l = plum(fovscan(y)[x]);
                        if (l < lwmin) lwmin = l;
                        if (l > lwmax) lwmax = l;
                }
        lwmax *= 1.01;
        if (lwmax > LMAX)
                lwmax = LMAX;
        bwmax = Bl(lwmax);
        if (lwmin < LMIN) {
                lwmin = LMIN;
                bwmin = Bl(LMIN);
        } else {                        /* duplicate bottom bin */
                bwmin = bwmax - (bwmax-Bl(lwmin))*HISTRES/(HISTRES-1);
                lwmin = Lb(bwmin);
        }
                                        /* (re)compute histogram */
        bwavg = 0.;
        histot = 0.;
        for (x = 0; x < HISTRES; x++)
                bwhist[x] = 0.;
                                        /* global average */
        if (!(what2do&DO_FIXHIST) || fixfrac < 1.-FTINY)
                for (y = 0; y < fvyr; y++)
                        for (x = 0; x < fvxr; x++) {
                                l = plum(fovscan(y)[x]);
                                if (l < lwmin+FTINY) continue;
                                if (l >= lwmax-FTINY) continue;
                                b = Bl(l);
                                w = what2do&DO_CWEIGHT ? centprob(x,y) : 1.;
                                bwavg += w*b;
                                bwhist[bwhi(b)] += w;
                                histot += w;
                        }
                                        /* average fixation points */
        if (what2do&DO_FIXHIST && nfixations > 0) {
                if (histot > FTINY)
                        w = fixfrac/(1.-fixfrac)*histot/nfixations;
                else
                        w = 1.;
                for (x = 0; x < nfixations; x++) {
                        l = plum(fovscan(fixlst[x][1])[fixlst[x][0]]);
                        if (l < lwmin+FTINY) continue;
                        if (l >= lwmax-FTINY) continue;
                        b = Bl(l);
                        bwavg += w*b;
                        bwhist[bwhi(b)] += w;
                        histot += w;
                }
        }
        bwavg /= histot;
        if (lwmin > LMIN+FTINY) {       /* add false samples at bottom */
                bwhist[1] *= 0.5;
                bwhist[0] += bwhist[1];
        }
}


static void
mkcumf(void)                    /* make cumulative distribution function */
{
        register int    i;
        register double sum;

        mhistot = 0.;           /* compute modified total */
        for (i = 0; i < HISTRES; i++)
                mhistot += modhist[i];

        sum = 0.;               /* compute cumulative function */
        for (i = 0; i < HISTRES; i++) {
                cumf[i] = sum/mhistot;
                sum += modhist[i];
        }
        cumf[HISTRES] = 1.;
}


static double
cf(                             /* return cumulative function at b */
        double  b
)
{
        double  x;
        register int    i;

        i = x = HISTRES*(b - bwmin)/(bwmax - bwmin);
        x -= (double)i;
        return(cumf[i]*(1.-x) + cumf[i+1]*x);
}


static double
BLw(                            /* map world luminance to display brightness */
        double  Lw
)
{
        double  b;

        if (Lw <= LMIN || (b = Bl(Lw)) <= bwmin+FTINY)
                return(Bldmin);
        if (b >= bwmax-FTINY)
                return(Bldmax);
        return(Bldmin + cf(b)*(Bldmax-Bldmin));
}


extern double
htcontrs(               /* human threshold contrast sensitivity, dL(La) */
        double  La
)
{
        double  l10La, l10dL;
                                /* formula taken from Ferwerda et al. [SG96] */
        if (La < 1.148e-4)
                return(1.38e-3);
        l10La = log10(La);
        if (l10La < -1.44)              /* rod response regime */
                l10dL = pow(.405*l10La + 1.6, 2.18) - 2.86;
        else if (l10La < -.0184)
                l10dL = l10La - .395;
        else if (l10La < 1.9)           /* cone response regime */
                l10dL = pow(.249*l10La + .65, 2.7) - .72;
        else
                l10dL = l10La - 1.255;

        return(exp10(l10dL));
}


extern double
clampf(                 /* histogram clamping function */
        double  Lw
)
{
        double  bLw, ratio;

        bLw = BLw(Lw);          /* apply current brightness map */
        ratio = what2do&DO_HSENS ? htcontrs(Lb(bLw))/htcontrs(Lw) : Lb(bLw)/Lw;
        return(ratio/(Lb1(bLw)*(Bldmax-Bldmin)*Bl1(Lw)));
}

extern double
crfactor(                       /* contrast reduction factor */
        double  Lw
)
{
        int     i = HISTRES*(Bl(Lw) - bwmin)/(bwmax - bwmin);
        double  bLw, ratio, Tdb;

        if (i <= 0)
                return(1.0);
        if (i >= HISTRES)
                return(1.0);
        bLw = BLw(Lw);
        ratio = what2do&DO_HSENS ? htcontrs(Lb(bLw))/htcontrs(Lw) : Lb(bLw)/Lw;
        Tdb = mhistot * (bwmax - bwmin) / HISTRES;
        return(modhist[i]*Lb1(bLw)*(Bldmax-Bldmin)*Bl1(Lw)/(Tdb*ratio));
}


#if ADJ_VEIL
static void
mkcrfimage(void)                        /* compute contrast reduction factor image */
{
        int     i;
        float   *crfptr;
        COLOR   *fovptr;

        if (crfimg == NULL)
                crfimg = (float *)malloc(fvxr*fvyr*sizeof(float));
        if (crfimg == NULL)
                syserror("malloc");
        crfptr = crfimg;
        fovptr = fovimg;
        for (i = fvxr*fvyr; i--; crfptr++, fovptr++)
                crfptr[0] = crfactor(plum(fovptr[0]));
}
#endif


extern int
mkbrmap(void)                   /* make dynamic range map */
{
        double  Tdb, b, s;
        double  ceiling, trimmings;
        register int    i;
                                        /* copy initial histogram */
        memcpy((void *)modhist, (void *)bwhist, sizeof(modhist));
        s = (bwmax - bwmin)/HISTRES;    /* s is delta b */
                                        /* loop until satisfactory */
        do {
                mkcumf();                       /* sync brightness mapping */
                if (mhistot <= histot*CVRATIO)
                        return(-1);             /* no compression needed! */
                Tdb = mhistot * s;
                trimmings = 0.;                 /* clip to envelope */
                for (i = 0, b = bwmin + .5*s; i < HISTRES; i++, b += s) {
                        ceiling = Tdb*clampf(Lb(b));
                        if (modhist[i] > ceiling) {
                                trimmings += modhist[i] - ceiling;
                                modhist[i] = ceiling;
                        }
                }
        } while (trimmings > histot*CVRATIO);

#if ADJ_VEIL
        mkcrfimage();                   /* contrast reduction image */
#endif

        return(0);                      /* we got it */
}


extern void
scotscan(               /* apply scotopic color sensitivity loss */
        COLOR   *scan,
        int     xres
)
{
        COLOR   ctmp;
        double  incolor, b, Lw;
        register int    i;

        for (i = 0; i < xres; i++) {
                Lw = plum(scan[i]);
                if (Lw >= TopMesopic)
                        incolor = 1.;
                else if (Lw <= BotMesopic)
                        incolor = 0.;
                else
                        incolor = (Lw - BotMesopic) /
                                        (TopMesopic - BotMesopic);
                if (incolor < 1.-FTINY) {
                        b = (1.-incolor)*slum(scan[i])*inpexp/SWNORM;
                        if (lumf == rgblum) b /= WHTEFFICACY;
                        setcolor(ctmp, b, b, b);
                        if (incolor <= FTINY)
                                setcolor(scan[i], 0., 0., 0.);
                        else
                                scalecolor(scan[i], incolor);
                        addcolor(scan[i], ctmp);
                }
        }
}


extern void
mapscan(                /* apply tone mapping operator to scanline */
        COLOR   *scan,
        int     xres
)
{
        double  mult, Lw, b;
        register int    x;

        for (x = 0; x < xres; x++) {
                Lw = plum(scan[x]);
                if (Lw < LMIN) {
                        setcolor(scan[x], 0., 0., 0.);
                        continue;
                }
                b = BLw(Lw);            /* apply brightness mapping */
                mult = (Lb(b) - ldmin)/(ldmax - ldmin)/(Lw*inpexp);
                if (lumf == rgblum) mult *= WHTEFFICACY;
                scalecolor(scan[x], mult);
        }
}


extern void
putmapping(                     /* put out mapping function */
        FILE    *fp
)
{
        double  b, s;
        register int    i;
        double  wlum, sf, dlum;

        sf = scalef*inpexp;
        if (lumf == cielum) sf *= WHTEFFICACY;
        s = (bwmax - bwmin)/HISTRES;
        for (i = 0, b = bwmin + .5*s; i < HISTRES; i++, b += s) {
                wlum = Lb(b);
                if (what2do&DO_LINEAR) {
                        dlum = sf*wlum;
                        if (dlum > ldmax) dlum = ldmax;
                        else if (dlum < ldmin) dlum = ldmin;
                        fprintf(fp, "%e %e\n", wlum, dlum);
                } else
                        fprintf(fp, "%e %e\n", wlum, Lb(BLw(wlum)));
        }
}
Revision:	3.15
Committed:	Sun Mar 28 20:33:14 2004 UTC (20 years, 1 month ago) by schorsch
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rad4R2P2, rad3R7P2, rad3R7P1, rad4R2, rad4R1, rad4R0, rad3R6, rad3R6P1, rad3R8, rad3R9, rad4R2P1
Changes since 3.14:	+66 -37 lines
Log Message:	Continued ANSIfication, and other fixes and clarifications.
#	User	Rev	Content
1	greg	3.1	#ifndef lint
2	schorsch	3.15	static const char RCSid[] = "$Id: pcond3.c,v 3.14 2003/06/30 14:59:12 schorsch Exp $";
3	greg	3.1	#endif
4			/*
5			* Routines for computing and applying brightness mapping.
6			*/
7
8	schorsch	3.14	#include <string.h>
9
10	greg	3.1	#include "pcond.h"
11
12
13	greg	3.5	#define CVRATIO 0.025 /* fraction of samples allowed > env. */
14	greg	3.1
15	gwlarson	3.10	#define LN_10 2.30258509299404568402
16			#define exp10(x) exp(LN_10*(x))
17	greg	3.1
18	greg	3.11	double modhist[HISTRES]; /* modified histogram */
19	greg	3.5	double mhistot; /* modified histogram total */
20	greg	3.11	double cumf[HISTRES+1]; /* cumulative distribution function */
21	greg	3.1
22	schorsch	3.15	static double centprob(int x, int y);
23			static void mkcumf(void);
24			static double cf(double b);
25			static double BLw(double Lw);
26			#if ADJ_VEIL
27			static void mkcrfimage(void);
28			#endif
29
30
31	greg	3.1
32	schorsch	3.15	extern void
33			getfixations( /* load fixation history list */
34			FILE *fp
35			)
36	greg	3.8	{
37			#define FIXHUNK 128
38			RESOLU fvres;
39			int pos[2];
40			register int px, py, i;
41			/* initialize our resolution struct */
42	greg	3.11	if ((fvres.rt=inpres.rt)&YMAJOR) {
43	greg	3.8	fvres.xr = fvxr;
44			fvres.yr = fvyr;
45			} else {
46			fvres.xr = fvyr;
47			fvres.yr = fvxr;
48			}
49			/* read each picture position */
50			while (fscanf(fp, "%d %d", &pos[0], &pos[1]) == 2) {
51			/* convert to closest index in foveal image */
52			loc2pix(pos, &fvres,
53			(pos[0]+.5)/inpres.xr, (pos[1]+.5)/inpres.yr);
54			/* include nine neighborhood samples */
55			for (px = pos[0]-1; px <= pos[0]+1; px++) {
56			if (px < 0 \|\| px >= fvxr)
57			continue;
58			for (py = pos[1]-1; py <= pos[1]+1; py++) {
59			if (py < 0 \|\| py >= fvyr)
60			continue;
61			for (i = nfixations; i-- > 0; )
62			if (fixlst[i][0] == px &&
63			fixlst[i][1] == py)
64			break;
65			if (i >= 0)
66			continue; /* already there */
67			if (nfixations % FIXHUNK == 0) {
68			if (nfixations)
69			fixlst = (short (*)[2])
70	greg	3.12	realloc((void *)fixlst,
71	greg	3.8	(nfixations+FIXHUNK)*
72			2*sizeof(short));
73			else
74			fixlst = (short (*)[2])malloc(
75			FIXHUNK2sizeof(short)
76			);
77			if (fixlst == NULL)
78			syserror("malloc");
79			}
80			fixlst[nfixations][0] = px;
81			fixlst[nfixations][1] = py;
82			nfixations++;
83			}
84			}
85			}
86			if (!feof(fp)) {
87			fprintf(stderr, "%s: format error reading fixation data\n",
88			progname);
89			exit(1);
90			}
91			#undef FIXHUNK
92			}
93
94
95	schorsch	3.15	extern void
96			gethisto( /* load precomputed luminance histogram */
97			FILE *fp
98			)
99	gwlarson	3.10	{
100	greg	3.11	double histo[MAXPREHIST];
101	gwlarson	3.10	double histart, histep;
102	schorsch	3.15	double b, lastb, w;
103	gwlarson	3.10	int n;
104			register int i;
105			/* load data */
106			for (i = 0; i < MAXPREHIST &&
107	greg	3.11	fscanf(fp, "%lf %lf", &b, &histo[i]) == 2; i++) {
108			if (i > 1 && fabs(b - lastb - histep) > .001) {
109	gwlarson	3.10	fprintf(stderr,
110			"%s: uneven step size in histogram data\n",
111			progname);
112			exit(1);
113			}
114			if (i == 1)
115	greg	3.11	if ((histep = b - (histart = lastb)) <= FTINY) {
116			fprintf(stderr,
117			"%s: illegal step in histogram data\n",
118			progname);
119			exit(1);
120			}
121	gwlarson	3.10	lastb = b;
122			}
123			if (i < 2 \|\| !feof(fp)) {
124			fprintf(stderr,
125			"%s: format/length error loading histogram (log10L %f at %d)\n",
126			progname, b, i);
127			exit(1);
128			}
129			n = i;
130			histart *= LN_10;
131			histep *= LN_10;
132			/* find extrema */
133			for (i = 0; i < n && histo[i] <= FTINY; i++)
134			;
135	greg	3.11	bwmin = histart + (i-.001)*histep;
136	gwlarson	3.10	for (i = n; i-- && histo[i] <= FTINY; )
137			;
138	greg	3.11	bwmax = histart + (i+1.001)*histep;
139	gwlarson	3.10	if (bwmax > Bl(LMAX))
140			bwmax = Bl(LMAX);
141			if (bwmin < Bl(LMIN))
142			bwmin = Bl(LMIN);
143			else /* duplicate bottom bin */
144			bwmin = bwmax - (bwmax-bwmin)*HISTRES/(HISTRES-1);
145			/* convert histogram */
146			bwavg = 0.; histot = 0.;
147			for (i = 0; i < HISTRES; i++)
148			bwhist[i] = 0.;
149			for (i = 0, b = histart; i < n; i++, b += histep) {
150	greg	3.11	if (b < bwmin+FTINY) continue;
151			if (b >= bwmax-FTINY) break;
152	gwlarson	3.10	w = histo[i];
153			bwavg += w*b;
154			bwhist[bwhi(b)] += w;
155			histot += w;
156			}
157			bwavg /= histot;
158			if (bwmin > Bl(LMIN)+FTINY) { /* add false samples at bottom */
159			bwhist[1] *= 0.5;
160			bwhist[0] += bwhist[1];
161			}
162			}
163
164
165	schorsch	3.15	static double
166			centprob( /* center-weighting probability function */
167			int x,
168			int y
169			)
170	greg	3.8	{
171			double xr, yr, p;
172			/* paraboloid, 0 at 90 degrees from center */
173			xr = (x - .5(fvxr-1))/90.; / 180 degree fisheye has fv?r == 90 */
174			yr = (y - .5*(fvyr-1))/90.;
175			p = 1. - xrxr - yryr;
176			return(p < 0. ? 0. : p);
177			}
178
179
180	schorsch	3.15	extern void
181			comphist(void) /* create foveal sampling histogram */
182	greg	3.8	{
183			double l, b, w, lwmin, lwmax;
184			register int x, y;
185	gwlarson	3.10	/* check for precalculated histogram */
186			if (what2do&DO_PREHIST)
187			return;
188	greg	3.8	lwmin = 1e10; /* find extrema */
189			lwmax = 0.;
190			for (y = 0; y < fvyr; y++)
191			for (x = 0; x < fvxr; x++) {
192			l = plum(fovscan(y)[x]);
193			if (l < lwmin) lwmin = l;
194			if (l > lwmax) lwmax = l;
195			}
196	greg	3.9	lwmax *= 1.01;
197			if (lwmax > LMAX)
198			lwmax = LMAX;
199	greg	3.8	bwmax = Bl(lwmax);
200	greg	3.9	if (lwmin < LMIN) {
201			lwmin = LMIN;
202			bwmin = Bl(LMIN);
203			} else { /* duplicate bottom bin */
204			bwmin = bwmax - (bwmax-Bl(lwmin))*HISTRES/(HISTRES-1);
205			lwmin = Lb(bwmin);
206			}
207	greg	3.8	/* (re)compute histogram */
208			bwavg = 0.;
209			histot = 0.;
210			for (x = 0; x < HISTRES; x++)
211			bwhist[x] = 0.;
212			/* global average */
213			if (!(what2do&DO_FIXHIST) \|\| fixfrac < 1.-FTINY)
214			for (y = 0; y < fvyr; y++)
215			for (x = 0; x < fvxr; x++) {
216			l = plum(fovscan(y)[x]);
217	greg	3.11	if (l < lwmin+FTINY) continue;
218			if (l >= lwmax-FTINY) continue;
219	greg	3.8	b = Bl(l);
220			w = what2do&DO_CWEIGHT ? centprob(x,y) : 1.;
221	gwlarson	3.10	bwavg += w*b;
222	greg	3.8	bwhist[bwhi(b)] += w;
223			histot += w;
224			}
225			/* average fixation points */
226			if (what2do&DO_FIXHIST && nfixations > 0) {
227			if (histot > FTINY)
228			w = fixfrac/(1.-fixfrac)*histot/nfixations;
229			else
230			w = 1.;
231			for (x = 0; x < nfixations; x++) {
232			l = plum(fovscan(fixlst[x][1])[fixlst[x][0]]);
233	greg	3.11	if (l < lwmin+FTINY) continue;
234			if (l >= lwmax-FTINY) continue;
235	greg	3.8	b = Bl(l);
236	gwlarson	3.10	bwavg += w*b;
237	greg	3.8	bwhist[bwhi(b)] += w;
238			histot += w;
239			}
240			}
241			bwavg /= histot;
242	greg	3.9	if (lwmin > LMIN+FTINY) { /* add false samples at bottom */
243			bwhist[1] *= 0.5;
244			bwhist[0] += bwhist[1];
245			}
246	greg	3.8	}
247
248
249	schorsch	3.15	static void
250			mkcumf(void) /* make cumulative distribution function */
251	greg	3.1	{
252			register int i;
253	greg	3.5	register double sum;
254	greg	3.1
255	greg	3.5	mhistot = 0.; /* compute modified total */
256			for (i = 0; i < HISTRES; i++)
257			mhistot += modhist[i];
258
259			sum = 0.; /* compute cumulative function */
260			for (i = 0; i < HISTRES; i++) {
261			cumf[i] = sum/mhistot;
262	greg	3.1	sum += modhist[i];
263			}
264			cumf[HISTRES] = 1.;
265			}
266
267
268	schorsch	3.15	static double
269			cf( /* return cumulative function at b */
270			double b
271			)
272	greg	3.1	{
273			double x;
274			register int i;
275
276			i = x = HISTRES*(b - bwmin)/(bwmax - bwmin);
277			x -= (double)i;
278			return(cumf[i](1.-x) + cumf[i+1]x);
279			}
280
281
282	schorsch	3.15	static double
283			BLw( /* map world luminance to display brightness */
284			double Lw
285			)
286	greg	3.1	{
287			double b;
288
289			if (Lw <= LMIN \|\| (b = Bl(Lw)) <= bwmin+FTINY)
290			return(Bldmin);
291			if (b >= bwmax-FTINY)
292			return(Bldmax);
293	greg	3.4	return(Bldmin + cf(b)*(Bldmax-Bldmin));
294	greg	3.1	}
295
296
297	schorsch	3.15	extern double
298			htcontrs( /* human threshold contrast sensitivity, dL(La) */
299			double La
300			)
301	greg	3.1	{
302			double l10La, l10dL;
303			/* formula taken from Ferwerda et al. [SG96] */
304			if (La < 1.148e-4)
305			return(1.38e-3);
306			l10La = log10(La);
307			if (l10La < -1.44) /* rod response regime */
308			l10dL = pow(.405*l10La + 1.6, 2.18) - 2.86;
309			else if (l10La < -.0184)
310			l10dL = l10La - .395;
311			else if (l10La < 1.9) /* cone response regime */
312			l10dL = pow(.249*l10La + .65, 2.7) - .72;
313			else
314			l10dL = l10La - 1.255;
315
316			return(exp10(l10dL));
317			}
318
319
320	schorsch	3.15	extern double
321			clampf( /* histogram clamping function */
322			double Lw
323			)
324	greg	3.1	{
325			double bLw, ratio;
326
327			bLw = BLw(Lw); /* apply current brightness map */
328			ratio = what2do&DO_HSENS ? htcontrs(Lb(bLw))/htcontrs(Lw) : Lb(bLw)/Lw;
329			return(ratio/(Lb1(bLw)(Bldmax-Bldmin)Bl1(Lw)));
330			}
331
332	schorsch	3.15	extern double
333			crfactor( /* contrast reduction factor */
334			double Lw
335			)
336	greg	3.11	{
337			int i = HISTRES*(Bl(Lw) - bwmin)/(bwmax - bwmin);
338			double bLw, ratio, Tdb;
339
340			if (i <= 0)
341			return(1.0);
342			if (i >= HISTRES)
343			return(1.0);
344			bLw = BLw(Lw);
345			ratio = what2do&DO_HSENS ? htcontrs(Lb(bLw))/htcontrs(Lw) : Lb(bLw)/Lw;
346			Tdb = mhistot * (bwmax - bwmin) / HISTRES;
347			return(modhist[i]Lb1(bLw)(Bldmax-Bldmin)Bl1(Lw)/(Tdbratio));
348			}
349
350
351			#if ADJ_VEIL
352	schorsch	3.15	static void
353			mkcrfimage(void) /* compute contrast reduction factor image */
354	greg	3.11	{
355			int i;
356			float *crfptr;
357			COLOR *fovptr;
358
359			if (crfimg == NULL)
360			crfimg = (float )malloc(fvxrfvyr*sizeof(float));
361			if (crfimg == NULL)
362			syserror("malloc");
363			crfptr = crfimg;
364			fovptr = fovimg;
365			for (i = fvxr*fvyr; i--; crfptr++, fovptr++)
366			crfptr[0] = crfactor(plum(fovptr[0]));
367			}
368			#endif
369
370	greg	3.1
371	schorsch	3.15	extern int
372			mkbrmap(void) /* make dynamic range map */
373	greg	3.1	{
374	greg	3.11	double Tdb, b, s;
375	greg	3.5	double ceiling, trimmings;
376	greg	3.1	register int i;
377			/* copy initial histogram */
378	schorsch	3.14	memcpy((void )modhist, (void )bwhist, sizeof(modhist));
379	greg	3.11	s = (bwmax - bwmin)/HISTRES; /* s is delta b */
380	greg	3.1	/* loop until satisfactory */
381	greg	3.5	do {
382			mkcumf(); /* sync brightness mapping */
383			if (mhistot <= histot*CVRATIO)
384			return(-1); /* no compression needed! */
385	greg	3.11	Tdb = mhistot * s;
386	greg	3.5	trimmings = 0.; /* clip to envelope */
387	greg	3.1	for (i = 0, b = bwmin + .5*s; i < HISTRES; i++, b += s) {
388	greg	3.11	ceiling = Tdb*clampf(Lb(b));
389	greg	3.5	if (modhist[i] > ceiling) {
390			trimmings += modhist[i] - ceiling;
391			modhist[i] = ceiling;
392			}
393	greg	3.1	}
394	greg	3.5	} while (trimmings > histot*CVRATIO);
395
396	greg	3.11	#if ADJ_VEIL
397			mkcrfimage(); /* contrast reduction image */
398			#endif
399
400	greg	3.5	return(0); /* we got it */
401	greg	3.1	}
402
403
404	schorsch	3.15	extern void
405			scotscan( /* apply scotopic color sensitivity loss */
406			COLOR *scan,
407			int xres
408			)
409	greg	3.1	{
410			COLOR ctmp;
411			double incolor, b, Lw;
412			register int i;
413
414			for (i = 0; i < xres; i++) {
415			Lw = plum(scan[i]);
416			if (Lw >= TopMesopic)
417			incolor = 1.;
418			else if (Lw <= BotMesopic)
419			incolor = 0.;
420			else
421			incolor = (Lw - BotMesopic) /
422			(TopMesopic - BotMesopic);
423			if (incolor < 1.-FTINY) {
424	greg	3.2	b = (1.-incolor)slum(scan[i])inpexp/SWNORM;
425			if (lumf == rgblum) b /= WHTEFFICACY;
426			setcolor(ctmp, b, b, b);
427	greg	3.1	if (incolor <= FTINY)
428			setcolor(scan[i], 0., 0., 0.);
429			else
430			scalecolor(scan[i], incolor);
431			addcolor(scan[i], ctmp);
432			}
433			}
434			}
435
436
437	schorsch	3.15	extern void
438			mapscan( /* apply tone mapping operator to scanline */
439			COLOR *scan,
440			int xres
441			)
442	greg	3.1	{
443			double mult, Lw, b;
444	greg	3.11	register int x;
445	greg	3.1
446	greg	3.11	for (x = 0; x < xres; x++) {
447			Lw = plum(scan[x]);
448	greg	3.1	if (Lw < LMIN) {
449	greg	3.11	setcolor(scan[x], 0., 0., 0.);
450	greg	3.1	continue;
451			}
452	greg	3.11	b = BLw(Lw); /* apply brightness mapping */
453			mult = (Lb(b) - ldmin)/(ldmax - ldmin)/(Lw*inpexp);
454	greg	3.1	if (lumf == rgblum) mult *= WHTEFFICACY;
455	greg	3.11	scalecolor(scan[x], mult);
456	greg	3.4	}
457			}
458
459
460	schorsch	3.15	extern void
461			putmapping( /* put out mapping function */
462			FILE *fp
463			)
464	greg	3.4	{
465			double b, s;
466			register int i;
467	greg	3.7	double wlum, sf, dlum;
468	greg	3.4
469			sf = scalef*inpexp;
470			if (lumf == cielum) sf *= WHTEFFICACY;
471			s = (bwmax - bwmin)/HISTRES;
472			for (i = 0, b = bwmin + .5*s; i < HISTRES; i++, b += s) {
473			wlum = Lb(b);
474	greg	3.7	if (what2do&DO_LINEAR) {
475			dlum = sf*wlum;
476			if (dlum > ldmax) dlum = ldmax;
477			else if (dlum < ldmin) dlum = ldmin;
478			fprintf(fp, "%e %e\n", wlum, dlum);
479			} else
480	greg	3.4	fprintf(fp, "%e %e\n", wlum, Lb(BLw(wlum)));
481	greg	3.1	}
482			}