大多數攝像機廠家的碼流輸出主流YUV420planar格式,即先連續存儲所有像素點的Y,緊接着存儲所有像素點的U,隨後是所有像素點的V。
但是在實際應用中發現雖同爲YUV420p格式,仍存在一些差異。
如:大華攝像機的爲YUV,而海康的爲YVU,數據量一致,但UV數據位置反了。
所以在YUV轉RGB的時候,採用OpenCV轉換函數cv::cvtColor的轉換類型也不一樣,前者爲CV_YUV2BGR_I420,後者爲CV_YUV2BGR_YV12。
C++實現如下:
bool YUV420ToBGR24( unsigned char* pY, unsigned char* pU, unsigned char* pV, unsigned char* pRGB24, int width, int height)
{
int yIdx, uIdx, vIdx, idx;
int offset = 0;
for (int i = 0; i < height; i++)
{
for (int j = 0; j < width; j++)
{
yIdx = i * width + j;
vIdx = (i / 4)* width + j / 2;
uIdx = (i / 4)* width + j / 2;
int R = (pY[yIdx] - 16) + 1.370805 * (pV[uIdx] - 128); // r分量
int G = (pY[yIdx] - 16) - 0.69825 * (pV[uIdx] - 128) - 0.33557 * (pU[vIdx] - 128); // g分量
int B = (pY[yIdx] - 16) + 1.733221 * (pU[vIdx] - 128); // b分量
R = R < 255 ? R : 255;
G = G < 255 ? G : 255;
B = B < 255 ? B : 255;
R = R < 0 ? 0 : R;
G = G < 0 ? 0 : G;
B = B < 0 ? 0 : B;
pRGB24[offset++] = (unsigned char)R;
pRGB24[offset++] = (unsigned char)G;
pRGB24[offset++] = (unsigned char)B;
}
}
return true;
}
具體參考
https://www.cnblogs.com/luoyinjie/p/7219319.html
https://blog.csdn.net/fuhanga123/article/details/51593794