学步园

本文转自http://blog.csdn.net/sangni007/article/details/8112486

在很多视频跟踪或分割中，总是需要初始化第一帧，即在第一帧上画一个框，或者标注前景与背景啊等等，今天就把初始化第一帧，在第一帧上画一个框的代码实现了一下，顺便复习一下OpenCV里面的鼠标召回事件，在此贴上代码，与大家分享，也方便以后查找。

#include "opencv2/opencv.hpp"
#include "opencv2/highgui/highgui.hpp"
#include <string>
#include <iostream>
#include <stdio.h>

using namespace cv;
using namespace std;

//最多对一个对象进行跟踪;
#define MAX_OBJECTS 1

//传递参数的class
class params
{
public:
 	
	Point loc1,loc2;
	string win_name;
	Mat src;
	Mat cur;
	int n;					//记录对象个数
	params() : n(0) {}
	// 	~params();
};

//鼠标事件
void mouseEvent(int event, int x, int y, int flags, void* param)  
{
	static bool check_line_state = FALSE;
	Mat tmp;
	params* p = (params*)param;
	//按下鼠标左键，存储初始位置;
	if( event == CV_EVENT_LBUTTONDOWN )
	{
		 if (p->n == MAX_OBJECTS)//判断是否已经有了跟踪对象;
		{
			cout<<"Fail! \n Only Can Tracking One Object!"<<endl;
			return ;
		}
		p->loc1.x = x;
		p->loc1.y = y;
		check_line_state = TRUE;
	}

	//按下鼠标左键且鼠标移动，画矩形框;
	else if (check_line_state && event == CV_EVENT_MOUSEMOVE)
	{
		if (p->n == MAX_OBJECTS)//判断是否已经有了跟踪对象;
		{
			cout<<"Fail! \n Only Can Tracking One Object!"<<endl;
			return ;
		}
		p->src.copyTo(tmp);
		rectangle(tmp, p->loc1, Point(x,y), CV_RGB(255,0,0), 2, 8 );
		imshow(p->win_name,tmp);
	}

	//左键弹起，画框结束;
	else if(event == CV_EVENT_LBUTTONUP)
	{
		if (p->n == MAX_OBJECTS)//判断是否已经有了跟踪对象;
		{
			cout<<"Fail! \n Only Can Tracking One Object!"<<endl;
			return ;
		}
		p->loc2.x = x;
		p->loc2.y = y;
		rectangle(p->src, p->loc1, Point(x,y), CV_RGB(255,0,0), 2, 8 );
		imshow(p->win_name,p->src);
		p->n++;
		check_line_state = FALSE;
	}
}

//初始化第一帧，画出要跟踪的对象
void InitialVideo(Mat& src, Rect& rect)
{
	params p;
	src.copyTo(p.src);
	p.win_name = "Initial Window";
	imshow(p.win_name, src);
	
	//鼠标召回事件
	setMouseCallback(p.win_name, &mouseEvent, &p); 
	cout<<"draw rect & press any key to end"<<endl;
	
	waitKey();

	//把得到的位置赋给rect
	rect.x = min(p.loc1.x, p.loc2.x);
	rect.y = min(p.loc1.y, p.loc2.y);
	rect.width = abs(p.loc1.x - p.loc2.x);
	rect.height = abs(p.loc1.y - p.loc2.y);

	destroyWindow("Initial Window");
}

int main()
{
	//从默认摄像头输入
	VideoCapture cap(0);
	//从视频输入
	//string filename = "D:/soccer.avi";
	//VideoCapture cap(filename); 

	if(!cap.isOpened())  // check if we succeeded
	{
		cout<<"couldn't open video file"<<endl;
		return -1;
	}

	Mat frame;
	bool isFirstFrame = TRUE;
	Rect rect;
        cap>>frame;//可能是因为电脑问题，导致第一帧显示不出来，所以就把第一帧先读一次
	for (;;)
	{
		cap>>frame;
		//初始化第一帧
		if ( isFirstFrame)
		{
			InitialVideo(frame,rect);
			 isFirstFrame = FALSE;
		}
		//其他操作
		rectangle(frame, rect, CV_RGB(255,0,0), 2, 8 );
		imshow("showSrc",frame);
		char key = (char)waitKey(5);
		switch (key)
		{
		case 27:
			return 0;
		case  ' ' :
			cout<<"save process"<<endl;
			break;
		default:
			break;
		}
	}
}