opencv怎么打开usb摄像头

Posted 2023-04-26

//Program to display a video from attached default camera device  
#include<iostream>  
#include<opencv2/opencv.hpp>  
  
using namespace std;  
using namespace cv;  
  
char *window_name = "Video";  
  
int main()  
  
    VideoCapture cap(0);  //此处默认USB摄像头
    if (!cap.isOpened())  
      
        cerr << "webCam could't be opened successfully" << endl;  
        return EXIT_FAILURE;  
      
    namedWindow(window_name);  
    while (char(waitKey(1)) != 'q'&&cap.isOpened())  
      
        Mat frame;  
        cap >> frame;  
        if (frame.empty())  
          
            cout << "Video over" << endl;  
            break;  
          
        imshow(window_name, frame);  
      

参考技术A 我为什么打不开摄像头呢？

Jetson TX2opencv3 打开usb摄像头

 

ubuntu2604

opencv3.4.0

 

https://blog.csdn.net/ultimate1212/article/details/80936175?utm_source=blogxgwz7

 

 

 

cmake_minimum_required(VERSION 2.8)
project(DisplayImage)  

set( CMAKE_CXX_FLAGS "-std=c++11 -O3" )

find_package( OpenCV REQUIRED )  
#if(CMAKE_VERSION VERSION_LESS "2.8.11")
  # Add OpenCV headers location to your include paths
  include_directories(
  include
  ${OpenCV_INCLUDE_DIRS}
   )
#endif()

#单个包添加
#add_executable( DisplayImage src/DisplayImage.cpp )  

#文件路径自动读取添加
AUX_SOURCE_DIRECTORY(./src DIR_SRCS)
ADD_EXECUTABLE(DisplayImage ${DIR_SRCS})
target_link_libraries( DisplayImage ${OpenCV_LIBS} )



#设置可执行文件的输出目录
SET(EXECUTABLE_OUTPUT_PATH ${PROJECT_SOURCE_DIR}/bin)     

　　

 

#include <iostream>
#include <opencv2/opencv.hpp>
#include <string>
using namespace cv;
using namespace std;
int main()
{
    VideoCapture capture(0);
    if(capture.isOpened())
    {
        cout<<"success"<<endl;
    }
    Mat frame;
    while (capture.isOpened())
    {
        capture >> frame;
        imshow("capture", frame);
        char key = static_cast<char>(cvWaitKey(10));//控制视频流的帧率，10ms一帧
        if (key == 27)  //按esc退出
            break;               
    }
    return 0;
}

　　报错问题

https://blog.csdn.net/dhaduce/article/details/80379792

 

笔者在进行测试时，出现如下错误：

libv4l2: error setting pixformat: Invalid argument
libv4l2: error setting pixformat: Invalid argument
libv4l2: error setting pixformat: Invalid argument
libv4l2: error setting pixformat: Invalid argument
VIDEOIO ERROR: V4L2: Pixel format of incoming image is unsupported by OpenCV
Couldn‘t connect to webcam.

OPENCV默认采用0号摄像头，TX2的0号摄像头是板子上自带的板上摄像头，而我们的usb摄像头是1号，故笔者使用如下代码，解决了问题

如果上述方法不能解决问题，可以尝试如下操作：

首先检查是否安装了v4l1compat.so

dpkg -S v4l1compat.so

　　若没有安装，则安装；若找到该文件，则跳过安装，进行下一步

apt-cache search libv4l
sudo apt-get install libv4l-ruby1.8

　　然后添加环境变量

export LD_PRELOAD=/usr/lib/aarch64-linux-gnueabihf/libv4l/v4l1compat.so
export LD_PRELOAD=/usr/lib/aarch64-linux-gnueabihf/libv4l/v4l2convert.so

　　

sudo ldconfig