题目：Opencv中的点追踪技术

Posted 2022-10-22 岩枭

题目：Opencv中的点追踪技术

代码实现：

#include "opencv2/video/tracking.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include "opencv2/highgui/highgui.hpp"
#include <opencv2/core/core.hpp>
#include <iostream>
#include <ctype.h>

using namespace cv;
using namespace std;

static void help()

	cout << "\\n\\n\\t该Demo演示了 Lukas-Kanade基于光流的lkdemo\\n";
	cout << "\\n\\t程序默认从摄像头读入视频，可以按需改为从视频文件读入图像\\n";
	cout << "\\n\\t操作说明: \\n"
		"\\t\\t通过点击在图像中添加/删除特征点\\n"
		"\\t\\tESC - 退出程序\\n"
		"\\t\\tr -自动进行追踪\\n"
		"\\t\\tc - 删除所有点\\n"
		"\\t\\tn - 开/光-夜晚模式\\n" << endl;


Point2f point;
bool addRemovePt = false;

//--------------------------------【onMouse( )回调函数】------------------------------------
//		描述：鼠标操作回调
//-------------------------------------------------------------------------------------------------
static void onMouse(int event, int x, int y, int /*flags*/, void* /*param*/)

	if (event == EVENT_LBUTTONDOWN)
	
		point = Point2f((float)x, (float)y);
		addRemovePt = true;
	


int main(int argc, char** argv)

	help();

	VideoCapture cap;

	TermCriteria termcrit(TermCriteria::MAX_ITER | TermCriteria::EPS, 20, 0.03);
	Size subPixWinSize(10, 10), winSize(31, 31);

	const int MAX_COUNT = 500;
	bool needToInit = false;
	bool nightMode = false;


	cap.open(0);

	if (!cap.isOpened())
	
		cout << "Could not initialize capturing...\\n";
		return 0;
	

	namedWindow("LK Demo", 1);
	setMouseCallback("LK Demo", onMouse, 0);

	Mat gray, prevGray, image;
	vector<Point2f> points[2];

	for (;;)
	
		Mat frame;
		cap >> frame;
		if (frame.empty())
			break;

		frame.copyTo(image);
		cvtColor(image, gray, COLOR_BGR2GRAY);

		if (nightMode)
			image = Scalar::all(0);

		if (needToInit)
		
			// 自动初始化
			goodFeaturesToTrack(gray, points[1], MAX_COUNT, 0.01, 10, Mat(), 3, 0, 0.04);
			cornerSubPix(gray, points[1], subPixWinSize, Size(-1, -1), termcrit);
			addRemovePt = false;
		
		else if (!points[0].empty())
		
			vector<uchar> status;
			vector<float> err;
			if (prevGray.empty())
				gray.copyTo(prevGray);
			calcOpticalFlowPyrLK(prevGray, gray, points[0], points[1], status, err, winSize,
				3, termcrit, 0, 0.001);
			size_t i, k;
			for (i = k = 0; i < points[1].size(); i++)
			
				if (addRemovePt)
				
					if (norm(point - points[1][i]) <= 5)
					
						addRemovePt = false;
						continue;
					
				

				if (!status[i])
					continue;

				points[1][k++] = points[1][i];
				circle(image, points[1][i], 3, Scalar(0, 255, 0), -1, 8);
			
			points[1].resize(k);
		

		if (addRemovePt && points[1].size() < (size_t)MAX_COUNT)
		
			vector<Point2f> tmp;
			tmp.push_back(point);

			cornerSubPix(gray, tmp, winSize, Size(-1, -1), termcrit);
			points[1].push_back(tmp[0]);
			addRemovePt = false;
		

		needToInit = false;
		imshow("LK Demo", image);

		char c = (char)waitKey(10);
		if (c == 27)
			break;
		switch (c)
		
		case 'r':
			needToInit = true;
			break;
		case 'c':
			points[0].clear();
			points[1].clear();
			break;
		case 'n':
			nightMode = !nightMode;
			break;
		

		std::swap(points[1], points[0]);
		cv::swap(prevGray, gray);
	

	return 0;

运行效果图：咳咳，为了读者方便，强行上博主丑照