我已经做了这个功能来计算CIE Lab颜色空间的颜色差异,但它缺乏速度.既然我不是一个

Java专家,我想知道有没有一些技巧可以在这里提高速度呢？

代码基于注释块中提到的matlab函数.

/**

* Compute the CIEDE2000 color-difference between the sample color with

* CIELab coordinates 'sample' and a standard color with CIELab coordinates

* 'std'

*

* Based on the article:

* "The CIEDE2000 Color-Difference Formula: Implementation Notes,

* Supplementary Test Data, and Mathematical Observations,", G. Sharma,

* W. Wu, E. N. Dalal, submitted to Color Research and Application,

* January 2004.

* available at http://www.ece.rochester.edu/~gsharma/ciede2000/

*/

public static double deltaE2000(double[] lab1, double[] lab2)

{

double L1 = lab1[0];

double a1 = lab1[1];

double b1 = lab1[2];

double L2 = lab2[0];

double a2 = lab2[1];

double b2 = lab2[2];

// Cab = sqrt(a^2 + b^2)

double Cab1 = Math.sqrt(a1 * a1 + b1 * b1);

double Cab2 = Math.sqrt(a2 * a2 + b2 * b2);

// CabAvg = (Cab1 + Cab2) / 2

double CabAvg = (Cab1 + Cab2) / 2;

// G = 1 + (1 - sqrt((CabAvg^7) / (CabAvg^7 + 25^7))) / 2

double CabAvg7 = Math.pow(CabAvg, 7);

double G = 1 + (1 - Math.sqrt(CabAvg7 / (CabAvg7 + 6103515625.0))) / 2;

// ap = G * a

double ap1 = G * a1;

double ap2 = G * a2;

// Cp = sqrt(ap^2 + b^2)

double Cp1 = Math.sqrt(ap1 * ap1 + b1 * b1);

double Cp2 = Math.sqrt(ap2 * ap2 + b2 * b2);

// CpProd = (Cp1 * Cp2)

double CpProd = Cp1 * Cp2;

// hp1 = atan2(b1, ap1)

double hp1 = Math.atan2(b1, ap1);

// ensure hue is between 0 and 2pi

if (hp1 < 0) {

// hp1 = hp1 + 2pi

hp1 += 6.283185307179586476925286766559;

}

// hp2 = atan2(b2, ap2)

double hp2 = Math.atan2(b2, ap2);

// ensure hue is between 0 and 2pi

if (hp2 < 0) {

// hp2 = hp2 + 2pi

hp2 += 6.283185307179586476925286766559;

}

// dL = L2 - L1

double dL = L2 - L1;

// dC = Cp2 - Cp1

double dC = Cp2 - Cp1;

// computation of hue difference

double dhp = 0.0;

// set hue difference to zero if the product of chromas is zero

if (CpProd != 0) {

// dhp = hp2 - hp1

dhp = hp2 - hp1;

if (dhp > Math.PI) {

// dhp = dhp - 2pi

dhp -= 6.283185307179586476925286766559;

} else if (dhp < -Math.PI) {

// dhp = dhp + 2pi

dhp += 6.283185307179586476925286766559;

}

}

// dH = 2 * sqrt(CpProd) * sin(dhp / 2)

double dH = 2 * Math.sqrt(CpProd) * Math.sin(dhp / 2);

// weighting functions

// Lp = (L1 + L2) / 2 - 50

double Lp = (L1 + L2) / 2 - 50;

// Cp = (Cp1 + Cp2) / 2

double Cp = (Cp1 + Cp2) / 2;

// average hue computation

// hp = (hp1 + hp2) / 2

double hp = (hp1 + hp2) / 2;

// identify positions for which abs hue diff exceeds 180 degrees

if (Math.abs(hp1 - hp2) > Math.PI) {

// hp = hp - pi

hp -= Math.PI;

}

// ensure hue is between 0 and 2pi

if (hp < 0) {

// hp = hp + 2pi

hp += 6.283185307179586476925286766559;

}

// LpSqr = Lp^2

double LpSqr = Lp * Lp;

// Sl = 1 + 0.015 * LpSqr / sqrt(20 + LpSqr)

double Sl = 1 + 0.015 * LpSqr / Math.sqrt(20 + LpSqr);

// Sc = 1 + 0.045 * Cp

double Sc = 1 + 0.045 * Cp;

// T = 1 - 0.17 * cos(hp - pi / 6) +

// + 0.24 * cos(2 * hp) +

// + 0.32 * cos(3 * hp + pi / 30) -

// - 0.20 * cos(4 * hp - 63 * pi / 180)

double hphp = hp + hp;

double T = 1 - 0.17 * Math.cos(hp - 0.52359877559829887307710723054658)

+ 0.24 * Math.cos(hphp)

+ 0.32 * Math.cos(hphp + hp + 0.10471975511965977461542144610932)

- 0.20 * Math.cos(hphp + hphp - 1.0995574287564276334619251841478);

// Sh = 1 + 0.015 * Cp * T

double Sh = 1 + 0.015 * Cp * T;

// deltaThetaRad = (pi / 3) * e^-(36 / (5 * pi) * hp - 11)^2

double powerBase = hp - 4.799655442984406;

double deltaThetaRad = 1.0471975511965977461542144610932 * Math.exp(-5.25249016001879 * powerBase * powerBase);

// Rc = 2 * sqrt((Cp^7) / (Cp^7 + 25^7))

double Cp7 = Math.pow(Cp, 7);

double Rc = 2 * Math.sqrt(Cp7 / (Cp7 + 6103515625.0));

// RT = -sin(delthetarad) * Rc

double RT = -Math.sin(deltaThetaRad) * Rc;

// de00 = sqrt((dL / Sl)^2 + (dC / Sc)^2 + (dH / Sh)^2 + RT * (dC / Sc) * (dH / Sh))

double dLSl = dL / Sl;

double dCSc = dC / Sc;

double dHSh = dH / Sh;

return Math.sqrt(dLSl * dLSl + dCSc * dCSc + dHSh * dHSh + RT * dCSc * dHSh);

}