public static unsafe void ToRgb24(Lab24* from, Rgb24* to, int length=1)
{
if (length < 1) return;
// 使用 OpenCV 中的算法实现
const float coeff0 = 0.39215686274509809f;
const float coeff1 = 0.0f;
const float coeff2 = 1.0f;
const float coeff3 = (-128.0f);
const float coeff4 = 1.0f;
const float coeff5 = (-128.0f);
Lab24* end = from + length;
float x, y, z,l,a,b;
int blue, green, red;
while (from != end)
{
l = from->L * coeff0 + coeff1;
a = from->A * coeff2 + coeff3;
b = from->B * coeff4 + coeff5;
l = (l + labLShift_32f) * (1.0f / labLScale_32f);
x = (l + a * 0.002f);
z = (l - b * 0.005f);
y = l * l * l;
x = x * x * x;
z = z * z * z;
blue = (int)((x * labBx_32f + y * labBy_32f + z * labBz_32f) * 255 + 0.5);
green = (int)((x * labGx_32f + y * labGy_32f + z * labGz_32f) * 255 + 0.5);
red = (int)((x * labRx_32f + y * labRy_32f + z * labRz_32f) * 255 + 0.5);
red = red < 0 ? 0 : red > 255 ? 255 : red;
green = green < 0 ? 0 : green > 255 ? 255 : green;
blue = blue < 0 ? 0 : blue > 255 ? 255 : blue;
to->Red = (byte)red;
to->Green = (byte)green;
to->Blue = (byte)blue;
from++;
to++;
}
}
public static unsafe void ToLab24(Byte* from, Lab24* to, int length = 1)
{
// 使用 OpenCV 中的算法实现
if (length < 1) return;
Byte* end = from + length;
int x, y, z;
int l, a, b;
bool flag;
while (from != end)
{
Byte val = *from;
Byte red = val;
Byte green = val;
Byte blue = val;
x = blue * labXb + green * labXg + red * labXr;
y = blue * labYb + green * labYg + red * labYr;
z = blue * labZb + green * labZg + red * labZr;
flag = x > labT;
x = (((x) + (1 << ((lab_shift) - 1))) >> (lab_shift));
if (flag)
x = icvLabCubeRootTab[x];
else
x = (((x * labSmallScale + labSmallShift) + (1 << ((lab_shift) - 1))) >> (lab_shift));
flag = z > labT;
z = (((z) + (1 << ((lab_shift) - 1))) >> (lab_shift));
if (flag == true)
z = icvLabCubeRootTab[z];
else
z = (((z * labSmallScale + labSmallShift) + (1 << ((lab_shift) - 1))) >> (lab_shift));
flag = y > labT;
y = (((y) + (1 << ((lab_shift) - 1))) >> (lab_shift));
if (flag == true)
{
y = icvLabCubeRootTab[y];
l = (((y * labLScale - labLShift) + (1 << ((2 * lab_shift) - 1))) >> (2 * lab_shift));
}
else
{
l = (((y * labLScale2) + (1 << ((lab_shift) - 1))) >> (lab_shift));
y = (((y * labSmallScale + labSmallShift) + (1 << ((lab_shift) - 1))) >> (lab_shift));
}
a = (((500 * (x - y)) + (1 << ((lab_shift) - 1))) >> (lab_shift)) + 129;
b = (((200 * (y - z)) + (1 << ((lab_shift) - 1))) >> (lab_shift)) + 128;
l = l > 255 ? 255 : l < 0 ? 0 : l;
a = a > 255 ? 255 : a < 0 ? 0 : a;
b = b > 255 ? 255 : b < 0 ? 0 : b;
to->L = (byte)l;
to->A = (byte)a;
to->B = (byte)b;
from++;
to++;
}
}
