Function main

example/opencv_optical_flow.cpp:116–287

This example shows how to read two images or use camera with OpenCV, transfer the frames to the GPU, and apply a naive optical flow algorithm written in OpenCL

// and apply a naive optical flow algorithm
// written in OpenCL
int main(int argc, char *argv[])
{
    // setup the command line arguments
    po::options_description desc;
    desc.add_options()
            ("help",  "show available options")
            ("camera", po::value<int>()->default_value(-1),
                                 "if not default camera, specify a camera id")
            ("image1", po::value<std::string>(), "path to image file 1")
            ("image2", po::value<std::string>(), "path to image file 2");

    // Parse the command lines
    po::variables_map vm;
    po::store(po::parse_command_line(argc, argv, desc), vm);
    po::notify(vm);

    //check the command line arguments
    if(vm.count("help"))
    {
        std::cout << desc << std::endl;
        return 0;
    }

    //OpenCV variables
    cv::Mat previous_cv_image;
    cv::Mat current_cv_image;
    cv::VideoCapture cap; //OpenCV camera handle

    //check for image paths
    if(vm.count("image1") && vm.count("image2"))
    {
        // Read image 1 with OpenCV
        previous_cv_image = cv::imread(vm["image1"].as<std::string>(),
                                       CV_LOAD_IMAGE_COLOR);
        if(!previous_cv_image.data){
            std::cerr << "Failed to load image" << std::endl;
            return -1;
        }

        // Read image 2 with opencv
        current_cv_image = cv::imread(vm["image2"].as<std::string>(),
                                      CV_LOAD_IMAGE_COLOR);
        if(!current_cv_image.data){
            std::cerr << "Failed to load image" << std::endl;
            return -1;
        }
    }
    else //by default use camera
    {
        //open camera
        cap.open(vm["camera"].as<int>());
        // read first frame
        cap >> previous_cv_image;
        if(!previous_cv_image.data){
            std::cerr << "failed to capture frame" << std::endl;
            return -1;
        }