测试opencv-CUDA是否安装成功简单程序

 getCudaEnabledDeviceCount()函数有不同返回值，可以用来判断opencv-CUDA是否安装成功

/** @brief Returns the number of installed CUDA-enabled devices.

Use this function before any other CUDA functions calls. If OpenCV is compiled without CUDA support,
this function returns 0. If the CUDA driver is not installed, or is incompatible, this function
returns -1.
 */
#include 
#include "opencv2/core.hpp"
#include "opencv2/cudaarithm.hpp"
using namespace std;
using namespace cv;
using namespace cv::cuda;
int main()
{
    int num_devices = getCudaEnabledDeviceCount();
    if (num_devices == 0 )
    {
        std::cout << "OpenCV is compiled without CUDA support" << endl;
        return -1;
    }
    else if (num_devices == -1)
    {
        std::cout << "CUDA driver is not installed" << endl;
        return -1;
    }
    else if (num_devices >= 1)
    {
        std::cout << "CUDA-Opencv can be used and the number of GPU is :" << num_devices << endl;
        return -1;
    }
    return 0;
}