三帧差分算法

 本文系转载，原文地址：http://blog.csdn.net/carson2005/article/details/42218701

int CallTime = 0;//定义调用次数计数器IplImage* BackGroundImage;//上一帧灰度图IplImage* DiffImage_1;//上一帧差分图的二值化图void ThreeFrmDiff(IplImage* pColorIn){    CallTime++;    if(CallTime > 10)//防止溢出    {        CallTime = 10;    }    CvSize ImageSize = cvSize(pColorIn->width,pColorIn->height);    IplImage* GrayImage = cvCreateImage(ImageSize,IPL_DEPTH_8U,1);//当前帧的灰度图    IplImage* GxImage = cvCreateImage(ImageSize,IPL_DEPTH_8U,1);//当前帧的X方向梯度图    IplImage* GyImage = cvCreateImage(ImageSize,IPL_DEPTH_8U,1);//当前帧的Y方向梯度图    IplImage* DiffImage = cvCreateImage(ImageSize,IPL_DEPTH_8U,1);//当前帧的差分图    IplImage* DiffImage_2 = cvCreateImage(ImageSize,IPL_DEPTH_8U,1);//前一帧差分图    IplImage* pyr = cvCreateImage(cvSize((ImageSize.width&-2)/2,(ImageSize.height&-2)/2),8,1); //进行腐蚀去除噪声的中间临时图片    uchar* DiffImageData_2;    DiffImageData_2 = (uchar*)DiffImage_2->imageData;//得到前一帧差分图的数据    int height,width,step;//定义图像的高，宽，步长    int SumInRect = 0;//指定矩形内图像数据之和    int y1, y2, x1, x2;//对运动目标画框时的四个坐标点位置    y1 = 0;    y2 = 0;    x1 = 0;    x2 = 0;    char Kx[9] = {1,0,-1,2,0,-2,1,0,-1};//X方向掩模，用于得到X方向梯度图    char Ky[9] = {1,2,1,0,0,0,-1,-2,-1};//Y方向掩模，用于得到Y方向梯度图    CvMat KX,KY;    KX = cvMat(3,3,CV_8S,Kx);//构建掩模内核    KY = cvMat(3,3,CV_8S,Ky);//构建掩模内核    cvCvtColor(pColorIn,GrayImage,CV_BGR2GRAY);//将当前帧转化为灰度图    cvSmooth(GrayImage,GrayImage,CV_GAUSSIAN,7,7);//进行平滑处理    cvFilter2D(GrayImage,GxImage,&KX,cvPoint(-1,-1));//得到X方向的梯度图    cvFilter2D(GrayImage,GyImage,&KY,cvPoint(-1,-1));//得到Y方向的梯度图    cvAdd(GxImage,GyImage,GrayImage,NULL);//得到梯度图    height = GrayImage->height;    width = GrayImage->width;    step = GrayImage->widthStep;    CvRect rect;//定义矩形框    if(CallTime == 1)//如果是第一帧    {        //对Image_1,BackGroundImage,DiffImage_1进行内存申请        BackGroundImage = cvCreateImage(ImageSize,IPL_DEPTH_8U,1);        DiffImage_1 = cvCreateImage(ImageSize,IPL_DEPTH_8U,1);        cvCopy(GrayImage,BackGroundImage,NULL);//如果是第一帧，设置为背景    }    else    {        cvAbsDiff(GrayImage,BackGroundImage,DiffImage);//得到当前帧的差分图        cvCopy(GrayImage,BackGroundImage,NULL);//将当前帧的梯度图作为下一帧的背景        cvThreshold(DiffImage,DiffImage,15,255,CV_THRESH_BINARY);//二值化当前差分图        if(CallTime > 2)//如果大于等于第三帧        {            cvAnd(DiffImage,DiffImage_1,DiffImage_2);//进行“与”运算，得到前一帧灰度图的“准确”运动目标            char str[256];            memset(str, '\0', 256*sizeof(char));            static int iCount = 0;            sprintf(str, "./img/%d.jpg", iCount++);            cvSaveImage(str, DiffImage_2);        }        cvPyrDown(DiffImage_2,pyr,7);//向下采样        cvErode(pyr,pyr,0,1);//腐蚀，消除小的噪声        cvPyrUp(pyr,DiffImage_2,7);        cvCopy(DiffImage,DiffImage_1,NULL);//备份当前差分图的二值化图    }    cvReleaseImage(&GxImage);    cvReleaseImage(&GyImage);    cvReleaseImage(&GrayImage);    cvReleaseImage(&DiffImage);    cvReleaseImage(&DiffImage_2);        cvReleaseImage(&pyr);}