opencv2, RGB 전환 Lab 색상 공간

struct BGR
{
	int b;
	int g;
	int r;

};

struct Lab
{
	double L;
	double a;
	double b;
};
void BGR2Lab(BGR &bgr, Lab &lab)
{
	double b, g, r;

	double x, y, z;



	b = bgr.b / 255.0;
	g = bgr.g / 255.0;
	r = bgr.r / 255.0;


	r = (r > 0.04045) ? pow((r + 0.055) / 1.055, 2.4) : r / 12.92;
	g = (g > 0.04045) ? pow((g + 0.055) / 1.055f, 2.4) : g / 12.92;
	b = (b > 0.04045) ? pow((b + 0.055) / 1.055f, 2.4) : b / 12.92;



	x = (r * 0.4124 + g * 0.3576 + b * 0.1805) / 0.95047;
	y = (r * 0.2126 + g * 0.7152 + b * 0.0722) / 1.00000;
	z = (r * 0.0193 + g * 0.1192 + b * 0.9505) / 1.08883;

	//std::cout << pow(x, 0.3333) << " " << pow(y, 0.3333) << " " << pow(z, 1 / 3) << " " << std::endl;
	x = (x > 0.008856) ? pow(x, 0.3333) : (7.787 * x) + 16.0 / 116.0;
	y = (y > 0.008856) ? pow(y, 0.3333) : (7.787 * y) + 16.0 / 116.0;
	z = (z > 0.008856) ? pow(z, 0.3333) : (7.787 * z) + 16.0 / 116.0;

	//std::cout << x << " " << y << " " << z << " " << std::endl;
	lab.L = (116.0 * y) - 16.0;
	lab.a = 500.0 * (x - y);
	lab.b = 200.0 * (y - z);



}
void Lab2BGR(Lab &lab, BGR &bgr)
{
	double b, g, r;
	
	double x, y, z;
	double min, max;
	double delta;

	y = (lab.L + 16.0) / 116.0;
	x = lab.a / 500.0 + y;
	z = y - lab.b / 200.0;

	x = 0.95047 * ((x * x * x > 0.008856) ? x * x * x : (x - 16 / 116.0) / 7.787);
	y = 1.00000 * ((y * y * y > 0.008856) ? y * y * y : (y - 16 / 116.0) / 7.787);
	z = 1.08883 * ((z * z * z > 0.008856) ? z * z * z : (z - 16 / 116.0) / 7.787);

	r = x *  3.2406 + y * -1.5372 + z * -0.4986;
	g = x * -0.9689 + y *  1.8758 + z *  0.0415;
	b = x *  0.0557 + y * -0.2040 + z *  1.0570;
//	std::cout << b << " " << g << " " << r << std::endl;

	r = (r > 0.0031308) ? (1.055 * pow(r, 0.4166) - 0.055) : 12.92 * r;
	g = (g > 0.0031308) ? (1.055 * pow(g, 0.4166) - 0.055) : 12.92 * g;
	b = (b > 0.0031308) ? (1.055 * pow(b, 0.4166) - 0.055) : 12.92 * b;

	bgr.b = MAX(0, MIN(1, b)) * 255;
	bgr.g = MAX(0, MIN(1, g)) * 255;
	bgr.r = MAX(0, MIN(1, r)) * 255;
	

}