应用场景：视频追踪在项目显示中可以起到很好的视觉效果，可以看到中间处理过程，对于教学及讲解能起到辅助性作用。
输入视频：来自之前推文中的video: Qt入门系列（五）
输出效果：http://mpvideo.qpic.cn/0bf2v4aakaaavuao4ygjb5pfbl6dawxqabia.f10002.mp4?dis_k=8ef0371b1cfbdbe901c4976fc5169511&dis_t=1655366327&vid=wxv_1353903403940020224&format_id=10002&support_redirect=0&mmversion=false
源代码实现：
代码语言：javascript复制/* OpenCV Application Tracing support demo. */
#include <iostream>
#include <opencv2/core.hpp>
#include <opencv2/imgproc.hpp>
#include <opencv2/highgui.hpp>
#include <opencv2/videoio.hpp>
#include <opencv2/core/utils/trace.hpp>
using namespace cv;
using namespace std;
static void process_frame(const cv::UMat& frame)
{
CV_TRACE_FUNCTION(); // OpenCV Trace macro for function
imshow("Live", frame);
UMat gray, processed;
cv::cvtColor(frame, gray, COLOR_BGR2GRAY);
Canny(gray, processed, 32, 64, 3);
imshow("Processed", processed);
}
int main(int argc, char** argv)
{
CV_TRACE_FUNCTION();
cv::CommandLineParser parser(argc, argv,
"{help h ? | | help message}"
"{n | 100 | number of frames to process }"
"{@video | 0 | video filename or cameraID }"
);
if (parser.has("help"))
{
parser.printMessage();
return 0;
}
VideoCapture capture;
std::string video = parser.get<string>("@video");
if (video.size() == 1 && isdigit(video[0]))
capture.open(parser.get<int>("@video"));
else
capture.open(video); // keep GStreamer pipelines
int nframes = 0;
if (capture.isOpened())
{
nframes = (int)capture.get(CAP_PROP_FRAME_COUNT);
cout << "Video " << video <<
": width=" << capture.get(CAP_PROP_FRAME_WIDTH) <<
", height=" << capture.get(CAP_PROP_FRAME_HEIGHT) <<
", nframes=" << nframes << endl;
}
else
{
cout << "Could not initialize video capturing...n";
return -1;
}
int N = parser.get<int>("n");
if (nframes > 0 && N > nframes)
N = nframes;
cout<<"N"<< N <<endl;
cout << "Start processing..." << endl
<< "Press ESC key to terminate" << endl;
UMat frame;
for (int i = 0; N > 0 ? (i < N) : true; i )
{
CV_TRACE_REGION("FRAME"); // OpenCV Trace macro for named "scope" region
{
CV_TRACE_REGION("read");
capture.read(frame);
if (frame.empty())
{
cerr << "Can't capture frame: " << i << std::endl;
break;
}
// OpenCV Trace macro for NEXT named region in the same C scope
// Previous "read" region will be marked complete on this line.
// Use this to eliminate unnecessary curly braces.
CV_TRACE_REGION_NEXT("process");
process_frame(frame);
CV_TRACE_REGION_NEXT("delay");
if (waitKey(1) == 27/*ESC*/)
break;
}
}
return 0;
}运行：
说明：视频效果显示的不是那么好，需要根据实际情况进行参数调节！
