opencv光流法對特定區域進行跟蹤
阿新 • • 發佈:2018-11-04
本例子使用了opencv3.0,利用滑鼠選擇矩形框,然後對選擇的區域進行跟蹤
//---------------------------------光流法對特定區域進行跟蹤-----------------
#include <iostream>
#include <opencv2/opencv.hpp>
#include <opencv2/video.hpp>
#include <opencv2/highgui.hpp>
#include <opencv2/imgproc.hpp>
#include <opencv2/core/core.hpp>
#include <cstdio>
using namespace std;
using namespace cv;
//------------------------------------【全域性函式宣告】------------------------------
void tracking(Mat &frame,Mat &output);
//-------------------------------------【全域性變數宣告】-------------------------------
string window_name = "flow tracking" ;
Mat gray; //當前幀圖片
Mat gray_prev; //預測幀圖片
Mat image;
vector<Point2f> points[2]; //point0為特徵點的原來位置,point1位特徵點新的位置
vector<uchar> status; //跟蹤特徵的狀態,特徵的流發現為1,否則為0
vector<float> err;
Rect selection;
Point origin; //定義原點,
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); //保證selection在畫面的裡邊
}
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;//定義視訊幀
Mat result;//定義結果
VideoCapture capture(0); //讀取視訊
if(capture.isOpened()) //如果視訊開啟成功,則進行以下步驟
{
while(true)
{
capture>>frame; //讀取當前視訊幀到frame中
frame.copyTo(image);
setMouseCallback(window_name,onMouse,0);
if(!frame.empty()) //如果當前幀不為空
{
tracking(image,result); //呼叫定義的函式,開始跟蹤
}
else
{
cout<<"沒有視訊幀"; //否則報錯
break;
}
int c = waitKey(50); //每隔50ms重新整理一次
if((char)c == 27) //使用者在50ms以內按下“esc”這個按鍵,則跳出迴圈
{
break;
}
switch (c)
{
case 'c': //停止追蹤
trackObject = 0;
break;
default:
break;
}
}
}
return 0;
}
void tracking(Mat &frame,Mat &output)
{
cvtColor(frame,gray,COLOR_BGR2GRAY); //將當前的視訊幀轉換為灰度圖,儲存到gray中
frame.copyTo(output); //拷貝當前幀到輸出output中
if(selectObject)
{
rectangle(output,Point(selection.x,selection.y),Point(selection.x+selection.width,
selection.y+selection.height),Scalar(255,0,0));
}
//滑鼠擡起時,進行檢測
if(trackObject == -1)
{
//選取selection區域的中心點為初始點
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); //如果前一幀為空,則複製當前幀到前一幀
}
if(points[0].size() == 0)
{
cout<<"這裡錯了;額"<<endl;
}
calcOpticalFlowPyrLK(gray_prev,gray, points[0],points[1],status,err);
//繪製跟蹤框圖,以point【1】為中心,與selection的長和寬相同的矩形
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);
//畫線,在output影象上,點initial[i]到點points[1][i]的直線段,顏色為(0,0,255)
line(output,points[0][0],points[1][0],Scalar(0,0,255),4,8);
//畫圓,在output影象上,圓心為point[1][i],半徑為3,圓的顏色為(0,255,0)
circle(output,points[1][0],6,Scalar(0,255,0),-1,8);
swap(points[1],points[0]); //交換特徵點容器points[0]和特徵點容器points[1]
swap(gray_prev,gray); //把當前幀的影象賦值為上一幀影象,以便傳入下一次迭代的calcOpticalFlowPyrLK
}
imshow(window_name,output); //在視窗window_name展示輸出的結果
}