c++ - OpenCV 速度问题

Question

我想以 ~30fps 转换许多点(整个 720p 图像最好)。现在我只是循环遍历一个蒙版并寻找标记的像素。然后我将每个标记的像素转换为一个新帧。有什么办法可以加快速度吗？该代码在 Windows 平板电脑上运行，所以我不知道 CUDA 是否可以提供帮助。

//Look for white pixels in mask image and transform them to new frame orientation
for (int row = 0; row < mask.rows; row++){
    for (int col = 0; col < mask.cols; col++){

        if (mask.at<uchar>(row, col) == 255){

            //Point in 2D hom
            p = (Mat_<double>(3, 1) << col, row, 1);
            p11 = CameraMatrix480.inv()*p;  //Pixel-->Camera


            //Project 2D Points to table
            double d = abs((p11 - midCam).dot(table_normal_cam)); //intersection of point with table surface is z value
            ps = p11 - d*table_normal_cam;
            p11 *= -Mat(p11 - ps).at<double>(2);

            //Get point in new frame in hom camera coordinates
            p11.copyTo(p_hom1(Range(0, 3), Range(0, 1)));
            p_hom2 = M * p_hom1; //p_hom in frame2

            //Point in frame2 in pixel coordinates
            p12 = (1 / p_hom2.at<double>(2))*(CameraMatrix480*p_hom2(Range(0, 3), Range(0, 1))); //Camera-->Pixel
            pixel = Point(p12.at<double>(0), p12.at<double>(1));

            //Check if new location is in the frame
            if (rect.contains(pixel)){
                RGB& rgb = output.ptr<RGB>(pixel.y)[pixel.x];
                rgb = white;
            }

        }
    }

Answer 1

未经测试，我认为逆相机矩阵的计算是代码中最昂贵的操作。假设相机矩阵是常数，您可以预先计算逆矩阵。

Mat invCameraMatrix(CameraMatrix480.inv());
...
p11 = invCameraMatrix*p;  //Pixel-->Camera
...

此外，您可以轻松地将 for 循环与 OpenMP 并行化，并检查这是否会提高性能。要使用 CUDA，您需要 Nvidia 显卡，您的 Windows 平板电脑设备可能不提供该显卡。