三帧差法运动目标检测代码及注释

      代码及注释仅供参考。

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);  
}