#include<iostream>
#include<opencv2\core\core.hpp>
#include<opencv2\highgui\highgui.hpp>
#include<opencv2\imgproc\imgproc.hpp>
using namespace std;
using namespace cv;

const unsigned char FORE_GROUD = 255;
int thresh = 30;
int maxArea = 100;
int times = 100;

Point getCenterPoint(Rect rect)
{
    Point cpt;
    cpt.x = rect.x + cvRound(rect.width/2.0);
    cpt.y = rect.y + cvRound(rect.height/2.0);
    return cpt;
}

int main(int argc,char*argv[])
{

    VideoCapture video(0);

    //判断如果video是否可以打开
    if(!video.isOpened())
        return -1;
    cout<<"Opened"<<endl;

    //用于保存当前帧的图片
    Mat currentBGRFrame;

    //用来保存上一帧和当前帧的灰度图片
    Mat previousSecondGrayFrame;
    Mat previousFirstGrayFrame;
    Mat currentGaryFrame;

    //保存两次的帧差
    Mat previousFrameDifference;//previousFrameFirst - previousFrameSecond的差分
    Mat currentFrameDifference;//currentFrame - previousFrameFirst;

    //用来保存帧差的绝对值
    Mat absFrameDifferece;

    //用来显示前景
    Mat previousSegmentation;
    Mat currentSegmentation;
    Mat segmentation;


    //显示前景
    namedWindow("segmentation",1);
    createTrackbar("阈值:","segmentation",&thresh,FORE_GROUD,NULL);
    createTrackbar("面积:","segmentation",&maxArea,FORE_GROUD,NULL);

    //帧数
    int numberFrame = 0;

    //形态学处理用到的算子
    Mat morphologyKernel = getStructuringElement(MORPH_RECT,Size(3,3),Point(-1,-1));

    for(;;)
    {
        //读取当前帧
        video >> currentBGRFrame;

        //判断当前帧是否存在
        if(!currentBGRFrame.data)
            continue;

        numberFrame++;
        //颜色空间的转换
        cvtColor(currentBGRFrame,currentGaryFrame,COLOR_BGR2GRAY);

        if( numberFrame == 1)
        {
            //保存当前帧的灰度图
            previousSecondGrayFrame = currentGaryFrame.clone();

            //显示视频
           imshow("video",currentBGRFrame);
            continue;
        }
        else if( numberFrame == 2)
        {
            //保存当前帧的灰度图
            previousFirstGrayFrame = currentGaryFrame.clone();

            //previousFirst - previousSecond
            subtract(previousFirstGrayFrame,previousSecondGrayFrame,previousFrameDifference,Mat(),CV_16SC1);

            //取绝对值
            absFrameDifferece = abs(previousFrameDifference);

            //位深的改变
            absFrameDifferece.convertTo(absFrameDifferece,CV_8UC1,1,0);

            //阈值处理
            threshold(absFrameDifferece,previousSegmentation,double(thresh),double(FORE_GROUD),THRESH_BINARY);

            //显示视频
           imshow("video",currentBGRFrame);
            continue;
        }

        else
        {
            //src1-src2
            //subtract(currentGaryFrame,previousFirstGrayFrame,currentFrameDifference,Mat(),CV_16SC1);

            //取绝对值
            //absFrameDifferece = abs(currentFrameDifference);
            absdiff(currentGaryFrame,previousFirstGrayFrame,absFrameDifferece);

            //位深的改变
            absFrameDifferece.convertTo(absFrameDifferece,CV_8UC1,1,0);

            //阈值处理
            threshold(absFrameDifferece,currentSegmentation,double(thresh),double(FORE_GROUD),THRESH_BINARY);

            //与运算
            bitwise_and(previousSegmentation,currentSegmentation,segmentation);

            //中值滤波
            medianBlur(segmentation,segmentation,3);

            //形态学处理(开闭运算)
            //morphologyEx(segmentation,segmentation,MORPH_OPEN,morphologyKernel,Point(-1,-1),1,BORDER_REPLICATE);
            morphologyEx(segmentation,segmentation,MORPH_CLOSE,morphologyKernel,Point(-1,-1),2,BORDER_REPLICATE);


            //找边界
            vector< vector<Point> > contours;
            vector<Vec4i> hierarchy;
            //复制segmentation
            Mat tempSegmentation = segmentation.clone();
            findContours( segmentation, contours, hierarchy, CV_RETR_EXTERNAL, CV_CHAIN_APPROX_SIMPLE, Point(0, 0) );//CV_RETR_TREE
            vector< vector<Point> > contours_poly( contours.size() );

            /*存储运动物体*/
            Rect rect = Rect(0,0,0,0);
            vector<Rect> boundRect;
            boundRect.clear();

            //画出运动物体
            for(unsigned int index = 0;index < contours.size() ;index++)
            {
                approxPolyDP( Mat(contours[index]), contours_poly[index], 3, true );
                Rect tmprect =  boundingRect( Mat(contours_poly[index]) );
                //cout<<getCenterPoint(rect)<<endl;
                int currentArea = tmprect.area();
                if( currentArea >= rect.area() && currentArea >= maxArea*times )
                    rect = tmprect;
            }
            rectangle(currentBGRFrame,rect,Scalar(0,255,255),2);

            //显示视频
            imshow("video",currentBGRFrame);

           //前景检测
            imshow("segmentation",segmentation);

            //保存当前帧的灰度图
            previousFirstGrayFrame = currentGaryFrame.clone();

            //保存当前的前景检测
            previousSegmentation = currentSegmentation.clone();
        }

        if(waitKey(33) == 'q')
            break;

    }
    return 0;
}