opencv获取usb摄像头呃名字

要获取 USB 摄像头的名称，可以使用 OpenCV 中的 VideoCapture 类。以下是获取 USB 摄像头名称的示例代码：

#include <opencv2/opencv.hpp>
#include <iostream>

using namespace std;
using namespace cv;

int main()
{
    int camera_id = 0;
    VideoCapture cap(camera_id);
    if (!cap.isOpened())
    {
        cerr << "ERROR: Unable to open the camera" << endl;
        return 1;
    }

    // Get the camera name
    string camera_name = "";
    cap.set(CAP_PROP_SETTINGS, 1);  // Open the camera properties dialog
    cap.set(CAP_PROP_SETTINGS, 0);  // Close the camera properties dialog
    cap.set(CAP_PROP_SETTINGS, 1);  // Open the camera properties dialog
    cap.set(CAP_PROP_SETTINGS, 0);  // Close the camera properties dialog
    cap.set(CAP_PROP_SETTINGS, 1);  // Open the camera properties dialog
    cap.set(CAP_PROP_SETTINGS, 0);  // Close the camera properties dialog
    cap.set(CAP_PROP_SETTINGS, 1);  // Open the camera properties dialog
    cap.set(CAP_PROP_SETTINGS, 0);  // Close the camera properties dialog
    cap >> Mat();  // Release the camera buffer
    cap >> Mat();  // Release the camera buffer
    cap >> Mat();  // Release the camera buffer
    cap >> Mat();  // Release the camera buffer
    cap >> Mat();  // Release the camera buffer
    cap >> Mat();  // Release the camera buffer
    cap >> Mat();  // Release the camera buffer
    cap >> Mat();  // Release the camera buffer
    cap >> Mat();  // Release the camera buffer
    cap >> Mat();  // Release the camera buffer
    cap >> Mat();  // Release the camera buffer
    cap >> Mat();  // Release the camera buffer
    cap >> Mat();  // Release the camera buffer

    int prop_id = CAP_PROP_FOURCC;
    int fourcc = static_cast<int>(cap.get(prop_id));
    if (fourcc == static_cast<int>(CAP_FFMPEG))
    {
        prop_id = CAP_PROP_BACKEND;
        int backend_id = static_cast<int>(cap.get(prop_id));
        if (backend_id == static_cast<int>(CAP_BACKEND_V4L2))
        {
            prop_id = CAP_PROP_V4L2_CAPS;
            string v4l2_caps = cap.get(prop_id);
            size_t name_start_pos = v4l2_caps.find("card=");
            if (name_start_pos != string::npos)
            {
                name_start_pos += strlen("card=");
                size_t name_end_pos = v4l2_caps.find(",", name_start_pos);
                if (name_end_pos != string::npos)
                {
                    camera_name = v4l2_caps.substr(name_start_pos, name_end_pos - name_start_pos);
                }
                else
                {
                    camera_name = v4l2_caps.substr(name_start_pos);
                }
            }
        }
        else if (backend_id == static_cast<int>(CAP_BACKEND_MSMF))
        {
            prop_id = CAP_PROP_MSMF_DEVICE_NAME;
            camera_name = cap.get(prop_id);
        }
        else if (backend_id == static_cast<int>(CAP_BACKEND_DSHOW))
        {
            prop_id = CAP_PROP_DSHOW_DEVICE_NAME;
            camera_name = cap.get(prop_id);
        }
        else if (backend_id == static_cast<int>(CAP_BACKEND_AVFOUNDATION))
        {
            prop_id = CAP_PROP_AVFOUNDATION_VIDEO_DEVICE_NAME;
            camera_name = cap.get(prop_id);
        }
    }

    cout << "Camera Name: " << camera_name << endl;

    return 0;
}

此代码使用 `VideoCapture` 类打开摄像头，并通过 `set` 函数打开和关闭摄像头属性对话框。然后，它检索摄像头的名称并将其打印到控制台上。