本例子使用了opencv3.0,利用鼠标选择矩形框,然后对选择的区域进行跟踪
//---------------------------------光流法对特定区域进行跟踪-----------------
#include
#include
#include
#include
#include
#include
#include
using namespace std;
using namespace cv;
//------------------------------------【全局函数声明】------------------------------
void tracking(Mat &frame,Mat &output);
//-------------------------------------【全局变量声明】-------------------------------
string window_name = "flow tracking";
Mat gray; //当前帧图片
Mat gray_prev; //预测帧图片
Mat image;
vector points[2]; //point0为特征点的原来位置,point1位特征点新的位置
vector status; //跟踪特征的状态,特征的流发现为1,否则为0
vector<float> err;
Rect selection;
Point origin; //定义原点,
Point pointCentral;
bool selectObject = false;
int trackObject = 0;
static void onMouse(int event,int x,int y,int ,void*)
{
if(selectObject)
{
selection.x=MIN(x,origin.x);
selection.y=MIN(y,origin.y);
selection.width = abs(x-origin.x);
selection.height = abs(y-origin.y);
selection &= Rect(0,0,image.cols,image.rows); //保证selection在画面的里边
}
switch (event)
{
case EVENT_LBUTTONDOWN:
origin = Point(x,y);
selection = Rect(x,y,0,0);
selectObject = true;
break;
case EVENT_LBUTTONUP:
selectObject = false;
if(selection.width > 0 && selection.height > 0)
{
trackObject = -1;
}
break;
}
}
int main() {
Mat frame;//定义视频帧
Mat result;//定义结果
VideoCapture capture(0); //读取视频
if(capture.isOpened()) //如果视频打开成功,则进行以下步骤
{
while(true)
{
capture>>frame; //读取当前视频帧到frame中
frame.copyTo(image);
setMouseCallback(window_name,onMouse,0);
if(!frame.empty()) //如果当前帧不为空
{
tracking(image,result); //调用定义的函数,开始跟踪
}
else
{
cout<<"没有视频帧"; //否则报错
break;
}
int c = waitKey(50); //每隔50ms刷新一次
if((char)c == 27) //用户在50ms以内按下“esc”这个按键,则跳出循环
{
break;
}
switch (c)
{
case 'c': //停止追踪
trackObject = 0;
break;
default:
break;
}
}
}
return 0;
}
void tracking(Mat &frame,Mat &output)
{
cvtColor(frame,gray,COLOR_BGR2GRAY); //将当前的视频帧转换为灰度图,保存到gray中
frame.copyTo(output); //拷贝当前帧到输出output中
if(selectObject)
{
rectangle(output,Point(selection.x,selection.y),Point(selection.x+selection.width,
selection.y+selection.height),Scalar(255,0,0));
}
//鼠标抬起时,进行检测
if(trackObject == -1)
{
//选取selection区域的中心点为初始点
pointCentral = Point(selection.x+selection.width/2,selection.y+selection.height/2);
points[0].push_back(pointCentral);
if(gray_prev.empty())
{
gray.copyTo(gray_prev); //如果前一帧为空,则复制当前帧到前一帧
}
if(points[0].size() == 0)
{
cout<<"这里错了;额"<0],points[1],status,err);
//绘制跟踪框图,以point【1】为中心,与selection的长和宽相同的矩形
rectangle(output,Point(points[1][0].x - selection.width/2,points[1][0].y+selection.height/2),
Point(points[1][0].x + selection.width/2,points[1][0].y-selection.height/2),Scalar(255,0,0),3,8,0);
//画线,在output图像上,点initial[i]到点points[1][i]的直线段,颜色为(0,0,255)
line(output,points[0][0],points[1][0],Scalar(0,0,255),4,8);
//画圆,在output图像上,圆心为point[1][i],半径为3,圆的颜色为(0,255,0)
circle(output,points[1][0],6,Scalar(0,255,0),-1,8);
swap(points[1],points[0]); //交换特征点容器points[0]和特征点容器points[1]
swap(gray_prev,gray); //把当前帧的图像赋值为上一帧图像,以便传入下一次迭代的calcOpticalFlowPyrLK
}
imshow(window_name,output); //在窗口window_name展示输出的结果
}