diff options
Diffstat (limited to 'xicc/cam02.c')
| -rw-r--r-- | xicc/cam02.c | 28 |
1 files changed, 10 insertions, 18 deletions
diff --git a/xicc/cam02.c b/xicc/cam02.c index 376d2c8..5140f04 100644 --- a/xicc/cam02.c +++ b/xicc/cam02.c @@ -9,7 +9,7 @@ * Conference, with the addition of the Viewing Flare * model described on page 487 of "Digital Color Management", * by Edward Giorgianni and Thomas Madden, and the - * Helmholtz-Kohlrausch effect, using the equation from + * Helmholtz-Kohlraush effect, using the equation from * the Bradford-Hunt 96C model as detailed in Mark Fairchild's * book "Color Appearance Models". * The Slight modification to the Hunt-Pointer-Estevez matrix @@ -40,9 +40,7 @@ /* TTBD: Should convert to using Timo Kunkel and Erik Reinhard's simplified - and improved version of CIECAM02 - [ "A Neurophysiology-Inspired Steady-State Color Appearance Model", - ie. "CIECAM02-KR" ? ] + and improved version of CIECAM02 (ie. "CIECAM02-KR"). The rgbp compression has it's problems in terms of perceptual uniformity. A color with one component near zero might shift @@ -107,7 +105,7 @@ XYZ space, the J value used to multiply Chroma, is limited to be equivalent to not less than A == 0.1. - The Helmholtz-Kohlrausch effect is crafted to have resonable + The Helmholtz-Kohlraush effect is crafted to have resonable effects over the range of J from 0 to 100, and have more moderate effects outside this range. @@ -138,11 +136,7 @@ #undef DISABLE_HPE /* Debug - disable just Hunt-Pointer_Estevez matrix */ #undef DISABLE_NONLIN /* Debug - wire rgbp to rgba */ #undef DISABLE_TTD /* Debug - disable ttd vector 'tilt' */ -#undef DISABLE_HHKR /* Debug - disable Helmholtz-Kohlrausch */ - - /* We reduce the HK effect from the Hunt equation, in the */ - /* light of real wold experiments. */ -#define HHKR_MUL 0.25 /* [0.25] - Helmholtz-Kohlrausch strength multiplier */ +#undef DISABLE_HHKR /* Debug - disable Helmholtz-Kohlraush */ #ifdef ENABLE_COMPR # define BC_WHMINY 0.2 /* [0.2] Compression direction minimum Y value */ @@ -175,7 +169,7 @@ #define DDULIMIT 0.34 /* [0.34] ab component k3:k1 ratio limit (must be < 1.0) */ #define SSMINcJ 0.005 /* [0.005] ab scale cJ minimum value */ #define JLIMIT 0.005 /* [0.005] J encoding cutover point straight line (0 - 1.0 range) */ -#define HKLIMIT 0.7 /* [0.7] Maximum Helmholtz-Kohlrausch lift out of 1.0 */ +#define HKLIMIT 0.7 /* [0.7] Maximum Helmholtz-Kohlraush lift */ #ifdef TRACKMINMAX double minss = 1e60; @@ -288,7 +282,7 @@ double Yf, /* Flare as a fraction of the reference white (Y range 0.0 .. 1.0) * double Yg, /* Flare as a fraction of the adapting/surround (Y range 0.0 .. 1.0) */ double Gxyz[3], /* The Glare white coordinates (typically the Ambient color) */ /* If <= 0 will Wxyz will be used. */ -int hk /* Flag, NZ to use Helmholtz-Kohlrausch effect */ +int hk /* Flag, NZ to use Helmholtz-Kohlraush effect */ ) { double tt, t1, t2; double tm[3][3]; @@ -946,10 +940,9 @@ double XYZ[3] JJ = J; #ifndef DISABLE_HHKR - /* Helmholtz-Kohlrausch effect */ + /* Helmholtz-Kohlraush effect */ if (s->hk && J < 1.0) { -// double kk = C/300.0 * sin(DBL_PI * fabs(0.5 * (h - 90.0))/180.0); - double kk = HHKR_MUL * C/300.0 * sin(DBL_PI * fabs(0.5 * (h - 90.0))/180.0); + double kk = C/300.0 * sin(DBL_PI * fabs(0.5 * (h - 90.0))/180.0); if (kk > 1e-6) /* Limit kk to a reasonable range */ kk = 1.0/(s->hklimit + 1.0/kk); JJ = J + (1.0 - (J > 0.0 ? J : 0.0)) * kk; @@ -1042,10 +1035,9 @@ double Jab[3] J = JJ; #ifndef DISABLE_HHKR - /* Undo Helmholtz-Kohlrausch effect */ + /* Undo Helmholtz-Kohlraush effect */ if (s->hk && J < 1.0) { -// double kk = C/300.0 * sin(DBL_PI * fabs(0.5 * (h - 90.0))/180.0); - double kk = HHKR_MUL * C/300.0 * sin(DBL_PI * fabs(0.5 * (h - 90.0))/180.0); + double kk = C/300.0 * sin(DBL_PI * fabs(0.5 * (h - 90.0))/180.0); if (kk > 1e-6) /* Limit kk to a reasonable range */ kk = 1.0/(s->hklimit + 1.0/kk); J = (JJ - kk)/(1.0 - kk); |