我发布这个是因为我已经在网上搜索试图找到一些解释导致的错误但没有找到任何错误。
所以我试图从 4 个不同的角度拍摄正在生长的植物的延时摄影。我有 4 个网络摄像头 (Logitech B525) 连接到我的树莓派 3。每小时一次，所有 4 个摄像头都应该拍摄尽可能窄和准确的时间同步帧。
在平稳运行后，有时几分钟有时几个小时，V4L 不再发现连接的摄像机或输出损坏的信息。产生错误的相机是随机的，因此没有坏的 USB 端口，也没有损坏的电缆。一段时间后，出现故障的摄像头再次开始工作，然后另一个摄像头出现故障，这种情况一直持续到所有摄像头都出现故障并且程序停止。
这是错误输出的示例
我的保存期编程输出：
cam 1 attached
cam 2 attached
cam 3 attached
cam 4 attached
18-10-23_10-00-00
saving file of frame 4.. '../cam4/cam4_image_18-10-23_10-00-00.jpg'
18-10-23_10-00-01
saving file of frame 3.. '../cam3/cam3_image_18-10-23_10-00-01.jpg'
18-10-23_10-00-02
saving file of frame 2..'../cam2/cam2_image_18-10-23_10-00-02.jpg'
18-10-23_10-00-02
saving file of frame 1.. '../cam1/cam1_image_18-10-23_10-00-02.jpg'
waiting for next capture!
然后发生错误：
libv4l2: error setting pixformat: Input-/Output Error
VIDEOIO ERROR: libv4l unable to ioctl S_FMT
libv4l2: error setting pixformat: Input-/Output Error
libv4l1: error setting pixformat: Input-/Output Error
libv4l2: error setting pixformat: Input-/Output Error
libv4l1: error setting pixformat: Input-/Output Error
VIDEOIO ERROR: libv4l unable to ioctl VIDIOCSPICT
cam 1 not attached
cam 2 attached
VIDEOIO ERROR: V4L: device /dev/video2: Unable to query number of channels
cam 3 not attached
libv4l2: error setting pixformat: Input-/Output Error
VIDEOIO ERROR: libv4l unable to ioctl S_FMT
libv4l2: error setting pixformat: Input-/Output Error
libv4l1: error setting pixformat: Input-/Output Error
libv4l2: error setting pixformat: Input-/Output Error
libv4l1: error setting pixformat: Input-/Output Error
VIDEOIO ERROR: libv4l unable to ioctl VIDIOCSPICT
cam 4 not attached
sh: 1: reboot: not found
libv4l2: error setting pixformat: Input-/Output Error
VIDEOIO ERROR: libv4l unable to ioctl S_FMT
libv4l2: error setting pixformat: Input-/Output Error
libv4l1: error setting pixformat: Input-/Output Error
libv4l2: error setting pixformat: Input-/Output Error
libv4l1: error setting pixformat: Input-/Output Error
VIDEOIO ERROR: libv4l unable to ioctl VIDIOCSPICT
cam 1 attached
cam 2 attached
cam 3 attached
VIDEOIO ERROR: V4L: device /dev/video3: Unable to query number of channels
cam 4 not attached
相机永远不会断开连接，并且始终存在于设备文件夹 /dev/videoX 中，我想可以假设这不是电源问题。
我导致错误的代码部分是开关部分一遍又一遍地重复，延迟 5 秒。我的猜测是 USB 带宽问题，因为 raspberry 只有一个 USB 2.0 总线分成 4 个端口。我尝试在关闭和再次打开捕获之间增加更多时间，但没有任何帮助。我错过了什么吗？
这是我的代码：
switch(4)
{
case 4:
{
VideoCapture cap4(3);
if(!cap4.isOpened())
{
cout<<"cam 4 not functional or attached!"<<endl;
}
else
{
//cap4.set(5, 30); //5=FPS settings
//cap4.set(38, 3); //38=Buffersize settings, Frames saved in Buffer
cap4.set(3,1280);//3=Width, Pixelcount
cap4.set(4,720); //4=Height, Pixelcount
Mat frame4;
cap4 >> frame4; // get a new frame from camera
waitKey(30); //wait for 2 Frames
cap4.release();
imshow("camera_4", frame4);
if(frame4.empty())
{
cerr<<"Something is wrong with the camera 4, could not get frame 4!"<<endl;
}
else
{
try
{
if(save_next_file)
{
string name4 = "../cam4/cam4_image_"+currentDateTime()+".jpg";
cout<<"saving file of frame 4.. '"<<name4<<"'"<<endl;
imwrite(name4.c_str(),frame4);
waitKey(30);
gettimeofday(&last_save, NULL); //reset the time interval
}
}
catch(cv::Exception e)
{
cout<<"error saving frame 4. >__<"<<endl;
}
}
}
}
case 3:
{
VideoCapture cap3(2);
if(!cap3.isOpened())
{
cout<<"cam 3 not functional or attached!"<<endl;
}
else
{
//cap3.set(5, 30); //5=FPS settings
//cap3.set(38, 3); //38=Buffersize settings, Frames saved in Buffer
cap3.set(3,1280);//3=Width, Pixelcount
cap3.set(4,720); //4=Height, Pixelcount
Mat frame3;
cap3 >> frame3; // get a new frame from camera
waitKey(30); //wait for 2 Frames
cap3.release();
imshow("camera_3", frame3);
if(frame3.empty())
{
cerr<<"Something is wrong with the camrea 3, could not get frame 3. >__<"<<endl;
}
else
{
try
{
if(save_next_file)
{
string name3 = "../cam3/cam3_image_"+currentDateTime()+".jpg";
cout<<"saving file of frame 3.. '"<<name3<<"'"<<endl;
imwrite(name3.c_str(),frame3);
waitKey(25);
gettimeofday(&last_save, NULL); //reset the time interval
}
}
catch(cv::Exception e)
{
cout<<"error saving frame 3."<<endl;
}
}
}
}
case 2:
{
VideoCapture cap2(1);
if(!cap2.isOpened())
{
cout<<"cam 2 not functional or attached!"<<endl;
}
else
{
//cap2.set(5, 30); //5=FPS settings
//cap2.set(38, 3); //38=Buffersize settings, Frames saved in Buffer
cap2.set(3,1280);//3=Width, Pixelcount
cap2.set(4,720); //4=Height, Pixelcount
Mat frame2;
cap2 >> frame2; // get a new frame from camera
waitKey(30); //wait for 2 Frames
cap2.release();
imshow("camera_2", frame2);
if(frame2.empty())
{
cerr << "Something is wrong with the camera 2, could not get frame 2!" << endl;
}
else
{
try
{
if(save_next_file)
{
string name2 = "../cam2/cam2_image_"+currentDateTime()+".jpg";
cout<<"saving file of frame 2..'"<<name2<<"'"<<endl;
imwrite(name2.c_str(),frame2);
waitKey(25);
gettimeofday(&last_save, NULL); //reset the time interval
}
}
catch(cv::Exception e)
{
cout<<"error saving frame 2. >__<"<<endl;
}
}
}
}
case 1:
{
VideoCapture cap1(0);
if(cap1.isOpened())
if(!cap1.isOpened())
{
cout<<"cam 1 not functional or attached!"<<endl;
}
else
{
//cap1.set(5, 30); //5=FPS settings
//cap1.set(38, 3); //38=Buffersize settings, Frames saved in Buffer
cap1.set(3,1280);//3=Width, Pixelcount
cap1.set(4,720); //4=Height, Pixelcount
Mat frame1;
cap1 >> frame1; // get a new frame from camera
waitKey(30); //wait for 2 Frames
cap1.release();
imshow("camera_1", frame1);
if(frame1.empty())
{
cerr << "Something is wrong with camera 1, could not get frame 1!" << endl;
}
else
{
try
{
if(save_next_file)
{
string name1 = "../cam1/cam1_image_"+currentDateTime()+".jpg";
cout<<"saving file of frame 1.. '"<<name1<<"'"<<endl;
imwrite(name1.c_str(),frame1);
waitKey(25);
gettimeofday(&last_save, NULL); //reset the time interval
}
}
catch(cv::Exception e)
{
cout<<"error saving frame 1!"<<endl;
}
}
}
}
}