opencv三帧差分法运动检测

基于帧间差分法进行升级的三帧差分法，不同的测试视频可以设置不同二值化阈值来增强效果。
根据实际情况进行形态学处理。

#include 
#include 
#include 

#define threshold_diff1 25 //设置简单帧差法阈值
#define threshold_diff2 25 //设置简单帧差法阈值

using namespace cv;
using namespace std;

int main(int argc,unsigned char* argv[])
{
    Mat img_src1,img_src2,img_src3;//3帧法需要3帧图片
    Mat img_dst,gray1,gray2,gray3;
    Mat gray_diff1,gray_diff2;//存储2次相减的图片
	Mat gray_diff11,gray_diff12;
	Mat gray_diff21,gray_diff22;
    Mat gray;//用来显示前景的
    bool pause=false;

    VideoCapture vido_file("test3.avi");//在这里改相应的文件名
    namedWindow("foreground",0);
    for (;;)
    {
        if(!false)
        {
            vido_file >>img_src1;
            cvtColor(img_src1,gray1,CV_BGR2GRAY);
        
            waitKey(33);
            vido_file >>img_src2;
            cvtColor(img_src2,gray2,CV_BGR2GRAY);
            imshow("video_src",img_src2);//

            waitKey(33);
            vido_file >>img_src3;
            cvtColor(img_src3,gray3,CV_BGR2GRAY);

			Sobel(gray1,gray1,	CV_8U,1,0,3,0.4,128);
			Sobel(gray2,gray2,	CV_8U,1,0,3,0.4,128);
			Sobel(gray3,gray3,	CV_8U,1,0,3,0.4,128);

            subtract(gray2,gray1,gray_diff11);//第二帧减第一帧
			subtract(gray1,gray2,gray_diff12);
			add(gray_diff11,gray_diff12,gray_diff1);
            subtract(gray3,gray2,gray_diff21);//第三帧减第二帧
			subtract(gray2,gray3,gray_diff22);
			add(gray_diff21,gray_diff22,gray_diff2);

            for(int i=0;i(i,j))>=threshold_diff1)//这里模板参数一定要用unsigned char，否则就一直报错
                        gray_diff1.at(i,j)=255;            //第一次相减阈值处理
                    else gray_diff1.at(i,j)=0;

                    if(abs(gray_diff2.at(i,j))>=threshold_diff2)//第二次相减阈值处理
                        gray_diff2.at(i,j)=255;
                    else gray_diff2.at(i,j)=0;
                }
            bitwise_and(gray_diff1,gray_diff2,gray);
			
			dilate(gray,gray,Mat());erode(gray,gray,Mat());
			
            imshow("foreground",gray);
        }
        if( cvWaitKey(33) >= 0 )
	    break;
    }
    return 0;
}