C 实现CIE X Y Z 计算公式

下面是一个简单的C代码实现CIE XYZ计算公式：

#include <stdio.h>

#define N 31    // 离散化的波长点数
#define k 100   // 常数k

// 光谱能量分布函数S(lambda)和CIE标准观察者函数x_bar(lambda)、y_bar(lambda)、z_bar(lambda)
double S[N] = {0.0001299000, 0.0002321000, 0.0004149000, 0.0007416000, 0.0013680000, 0.0022360000, 0.0042430000, 0.0076500000, 0.0143100000, 0.0231900000, 0.0435100000, 0.0776300000, 0.1343800000, 0.2147700000, 0.2839000000, 0.3285000000, 0.3482800000, 0.3480600000, 0.3362000000, 0.3187000000, 0.2908000000, 0.2511000000, 0.1953600000, 0.1421000000, 0.0956400000, 0.0579500100, 0.0320100000, 0.0147000000, 0.0049000000, 0.0024000000, 0.0093000000, 0.0291000000};
double x_bar[N] = {0.0000039170, 0.0000069650, 0.0000123900, 0.0000220200, 0.0000390000, 0.0000640000, 0.0001200000, 0.0002170000, 0.0003960000, 0.0006400000, 0.0012100000, 0.0021800000, 0.0040000000, 0.0073000000, 0.0116000000, 0.0168400000, 0.0230000000, 0.0298000000, 0.0380000000, 0.0480000000, 0.0600000000, 0.0739000000, 0.0909800000, 0.1126000000, 0.1390200000, 0.1693000000, 0.2080200000, 0.2586000000, 0.3230000000, 0.4073000000, 0.5030000000, 0.6082000000};
double y_bar[N] = {0.0000001462, 0.0000002611, 0.0000004642, 0.0000008316, 0.0000015400, 0.0000025300, 0.0000047630, 0.0000087560, 0.0000161720, 0.0000256100, 0.0000465700, 0.0000823900, 0.0001400000, 0.0002040000, 0.0003142000, 0.0004686000, 0.0006800000, 0.0009640000, 0.0013500000, 0.0019100000, 0.0026500000, 0.0036100000, 0.0049500000, 0.0067600000, 0.0090300000, 0.0120100000, 0.0168400000, 0.0233300000, 0.0320100000, 0.0434000000, 0.0578500000, 0.0764000000};
double z_bar[N] = {0.0006061000, 0.0010860000, 0.0019460000, 0.0034860000, 0.0064500010, 0.0105500100, 0.0200500100, 0.0362100000, 0.0678500100, 0.1102000000, 0.2074000000, 0.3713000000, 0.6456000000, 1.0390501000, 1.3856000000, 1.6229600000, 1.7470600000, 1.7826000000, 1.7721100000, 1.7441000000, 1.6692000000, 1.5281000000, 1.2876400000, 1.0419000000, 0.8129501000, 0.6162000000, 0.4651800000, 0.3533000000, 0.2720000000, 0.2123000000, 0.1582000000, 0.1117000000};

int main()
{
    double lambda[N] = {380, 390, 400, 410, 420, 430, 440, 450, 460, 470, 480, 490, 500, 510, 520, 530, 540, 550, 560, 570, 580, 590, 600, 610, 620, 630, 640, 650, 660, 670, 680, 690, 700};    // 离散化的波长
    double X = 0, Y = 0, Z = 0;
    int i;

    for(i = 0; i < N; i++) {
        X += lambda[i] * S[i] * x_bar[i];    // 计算X值
        Y += lambda[i] * S[i] * y_bar[i];    // 计算Y值
        Z += lambda[i] * S[i] * z_bar[i];    // 计算Z值
    }

    X *= k;
    Y *= k;
    Z *= k;

    printf("CIE XYZ = (%f, %f, %f)\n", X, Y, Z);

    return 0;
}

注意，上述代码中的常数、函数值、波长等都是手动输入的，实际应用中需要根据具体的光源和光谱数据进行调整。