sRGB XYZ Lab颜色空间相互转换及相关计算的类

清疚 2022-08-08 05:28 222阅读 0赞

# sRGB XYZ Lab颜色空间相互转换及相关计算的类 #

using System;  
using System.Collections.Generic;  
using System.Text;  
using System.Windows.Forms;

namespace CRS  
\{  
/// <完成sRGB XYZ Lab颜色空间相互转换及相关计算的类>  
///  
/// </summary>  
internal class ColorSpaceTransform  
\{  
public static double\[\] sRGB2XYZ(double \[\] sRGB)  
\{  
double\[\] XYZ = new double\[3\];  
double sR, sG, sB;  
sR = sRGB\[0\];  
sG = sRGB\[1\];  
sB = sRGB\[2\];  
sR /= 255;  
sG /= 255;  
sB /= 255;

if (sR<=0.04045)  
\{  
sR = sR / 12.92;  
\}  
else  
\{  
sR = Math.Pow(((sR + 0.055) / 1.055), 2.4);  
\}

if (sG <= 0.04045)  
\{  
sG = sG / 12.92;  
\}  
else  
\{  
sG = Math.Pow(((sG + 0.055) / 1.055), 2.4);  
\}

if (sB <= 0.04045)  
\{  
sB = sB / 12.92;  
\}  
else  
\{  
sB = Math.Pow(((sB + 0.055) / 1.055), 2.4);  
\}

XYZ\[0\] = 41.24 \* sR + 35.76 \* sG + 18.05 \* sB;  
XYZ\[1\] = 21.26 \* sR + 71.52 \* sG + 7.2 \* sB;  
XYZ\[2\] = 1.93 \* sR + 11.92 \* sG + 95.05 \* sB;

return XYZ;  
\}  
public static int\[\] XYZ2sRGB(double \[\] XYZ)  
\{  
int\[\] sRGB = new int\[3\];  
double X, Y, Z;  
double dr, dg, db;  
X = XYZ\[0\];  
Y = XYZ\[1\];  
Z = XYZ\[2\];

dr = 0.032406 \* X - 0.015371 \* Y - 0.0049895 \* Z;  
dg = -0.0096891 \* X + 0.018757 \* Y + 0.00041914 \* Z;  
db = 0.00055708 \* X - 0.0020401 \* Y + 0.01057 \* Z;

if (dr<=0.00313)  
\{  
dr = dr \* 12.92;  
\}  
else  
\{  
dr = Math.Exp(Math.Log(dr) / 2.4) \* 1.055 - 0.055;  
\}

if (dg <= 0.00313)  
\{  
dg = dg \* 12.92;  
\}  
else  
\{  
dg = Math.Exp(Math.Log(dg) / 2.4) \* 1.055 - 0.055;  
\}

if (db <= 0.00313)  
\{  
db = db \* 12.92;  
\}  
else  
\{  
db = Math.Exp(Math.Log(db) / 2.4) \* 1.055 - 0.055;  
\}

dr = dr \* 255;  
dg = dg \* 255;  
db = db \* 255;

dr = Math.Min(255, dr);  
dg = Math.Min(255, dg);  
db = Math.Min(255, db);

sRGB\[0\] = (int)(dr + 0.5);  
sRGB\[1\] = (int)(dg + 0.5);  
sRGB\[2\] = (int)(db + 0.5);

return sRGB;  
\}  
public static double\[\] XYZ2Lab(double\[\] XYZ,double Xw,double Yw,double Zw)  
\{  
double\[\] Lab = new double\[3\];  
double X, Y, Z;  
X = XYZ\[0\];  
Y = XYZ\[1\];  
Z = XYZ\[2\];  
double Xn, Yn, Zn;  
Xn = Xw;  
Yn = Yw;  
Zn = Zw;  
double XXn, YYn, ZZn;  
XXn = X / Xn;  
YYn = Y / Yn;  
ZZn = Z / Zn;

double fx, fy, fz;

if (XXn > 0.008856)  
\{  
fx = Math.Pow(XXn, 0.333333);  
\}  
else  
\{  
fx = 7.787 \* XXn + 0.137931;  
\}

if (YYn > 0.008856)  
\{  
fy = Math.Pow(YYn, 0.333333);  
\}  
else  
\{  
fy = 7.787 \* YYn + 0.137931;  
\}

if (ZZn > 0.008856)  
\{  
fz = Math.Pow(ZZn, 0.333333);  
\}  
else  
\{  
fz = 7.787 \* ZZn + 0.137931;  
\}

Lab\[0\] = 116 \* fy - 16;  
Lab\[1\] = 500 \* (fx - fy);  
Lab\[2\] = 200 \* (fy - fz);

return Lab;  
\}  
public static double\[\] Lab2XYZ(double\[\] Lab)  
\{  
double\[\] XYZ = new double\[3\];  
double L, a, b;  
double fx, fy, fz;  
double Xn, Yn, Zn;  
Xn = 95.04;  
Yn = 100;  
Zn = 108.89;

L = Lab\[0\];  
a = Lab\[1\];  
b = Lab\[2\];

fy = (L + 16) / 116;  
fx = a / 500 + fy;  
fz = fy - b / 200;

if (fx>0.2069)  
\{  
XYZ\[0\] = Xn \* Math.Pow(fx, 3);  
\}  
else  
\{  
XYZ\[0\] = Xn \* (fx - 0.1379) \* 0.1284;  
\}

if ((fy > 0.2069) || (L>8))  
\{  
XYZ\[1\] = Yn \* Math.Pow(fy, 3);  
\}  
else  
\{  
XYZ\[1\] = Yn \* (fy - 0.1379) \* 0.1284;  
\}

if (fz > 0.2069)  
\{  
XYZ\[2\] = Zn \* Math.Pow(fz, 3);  
\}  
else  
\{  
XYZ\[2\] = Zn \* (fz - 0.1379) \* 0.1284;  
\}

return XYZ;  
\}  
\}  
\}

此类是CRS工程的一部分，用于常用的色度空间的转换计算。在VS08下经过测试，计算结果正确。

写代码只为了完成功能，很少考虑复杂度，内存开销等问题

本文出自 “moto” 博客