OpenCV读视频文件和运动问题检测
cvRunningAvg
opencv中的函数，用来更新移动平均。用法：
void cvRunningAvg(const CvArr * image,
CvArr* acc,
double alpha,
const CvArr* mask=NULL)
image:输入图像，1或3通道，8比特或32比特的float型
acc:累加器，和image一样大小
alpha：更新时，image所占的权重
mask：操作符掩码
if mask(x,y)!= 0 (1-alpha)*acc(x,y)+alpha*image(x,y) =>acc(x,y)
#if 0
#include <stdio.h>
#include <cv.h>
#include <cxcore.h>
#include <highgui.h>
#pragma comment(lib, "cv.lib")
#pragma comment(lib, "cxcore.lib")
#pragma comment(lib, "highgui.lib")
int main( int argc, char** argv )
{
//声明IplImage指针
IplImage* pFrame = NULL;
IplImage* pFrImg = NULL;
IplImage* pBkImg = NULL;
CvMat* pFrameMat = NULL;
CvMat* pFrMat = NULL;
CvMat* pBkMat = NULL;
CvCapture* pCapture = NULL;
int nFrmNum = 0;
//创建窗口
cvNamedWindow("video", 1);
cvNamedWindow("background",1);
cvNamedWindow("foreground",1);
//使窗口有序排列
cvMoveWindow("video", 30, 0);
cvMoveWindow("background", 360, 0);
cvMoveWindow("foreground", 690, 0);
if( !(pCapture = cvCaptureFromAVI(".\\test.avi")))
{
//pCapture = cvCaptureFromCAM(-1))
fprintf(stderr, "Can not open camera.\n");
return -2;
}
//逐帧读取视频
while(pFrame = cvQueryFrame( pCapture ))
{
nFrmNum++;
//如果是第一帧，需要申请内存，并初始化
if(nFrmNum == 1)
{
pBkImg = cvCreateImage(cvSize(pFrame->width, pFrame->height), IPL_DEPTH_8U,1);
pFrImg = cvCreateImage(cvSize(pFrame->width, pFrame->height), IPL_DEPTH_8U,1);
pBkMat = cvCreateMat(pFrame->height, pFrame->width, CV_32FC1);
pFrMat = cvCreateMat(pFrame->height, pFrame->width, CV_32FC1);
pFrameMat = cvCreateMat(pFrame->height, pFrame->width, CV_32FC1);
//转化成单通道图像再处理
cvCvtColor(pFrame, pBkImg, CV_BGR2GRAY);
cvCvtColor(pFrame, pFrImg, CV_BGR2GRAY);
cvConvert(pFrImg, pFrameMat);
cvConvert(pFrImg, pFrMat);
cvConvert(pFrImg, pBkMat);
}
else
{
cvCvtColor(pFrame, pFrImg, CV_BGR2GRAY);
cvConvert(pFrImg, pFrameMat);
//高斯滤波先，以平滑图像
//cvSmooth(pFrameMat, pFrameMat, CV_GAUSSIAN, 3, 0, 0);
//当前帧跟背景图相减
cvAbsDiff(pFrameMat, pBkMat, pFrMat);
//二值化前景图
cvThreshold(pFrMat, pFrImg, 60, 255.0, CV_THRESH_BINARY);
//进行形态学滤波，去掉噪音
//cvErode(pFrImg, pFrImg, 0, 1);
//cvDilate(pFrImg, pFrImg, 0, 1);
//更新背景
cvRunningAvg(pFrameMat, pBkMat, 0.003, 0);
//将背景转化为图像格式，用以显示
cvConvert(pBkMat, pBkImg);
//显示图像
cvShowImage("video", pFrame);
cvShowImage("background", pBkImg);
cvShowImage("foreground", pFrImg);
//如果有按键事件，则跳出循环
//此等待也为cvShowImage函数提供时间完成显示
//等待时间可以根据CPU速度调整
if( cvWaitKey(20) >= 0 )
{
break;
}
}
}
cvWaitKey();
//销毁窗口
cvDestroyWindow("video");
cvDestroyWindow("background");
cvDestroyWindow("foreground");
//释放图像和矩阵
cvReleaseImage(&pFrImg);
cvReleaseImage(&pBkImg);
cvReleaseMat(&pFrameMat);
cvReleaseMat(&pFrMat);
cvReleaseMat(&pBkMat);
cvReleaseCapture(&pCapture);
return 0;
}
#else
#include <cv.h>
#include <highgui.h>
#pragma comment(lib, "cv.lib")
#pragma comment(lib, "cxcore.lib")
#pragma comment(lib, "highgui.lib")
int main( int argc, char** argv )
{
CvCapture* capture = NULL;
IplImage *frame = NULL;
IplImage *frame_last = NULL;//存储上一帧
IplImage *m_out_image = NULL;
IplImage* frame_gray = NULL;
IplImage* frame_gray_last = NULL;
IplImage* m_out_image_copy = NULL;
int nFrmNum = 0;
//capture = cvCaptureFromCAM(-1);
capture = cvCaptureFromAVI(".\\test.avi");
//创建窗口
cvNamedWindow( "result", 1 );
cvNamedWindow("差分");
//逐帧读取视频
while(frame = cvQueryFrame( capture ))
{
nFrmNum++;
//如果是第一帧，需要申请内存，并初始化
if(nFrmNum == 1)
{
frame_last = cvCreateImage(cvSize(frame->width,frame->height),IPL_DEPTH_8U, frame->nChannels);
cvCopy(frame,frame_last);
}
else
{
frame_gray = cvCreateImage(cvSize(frame->width,frame->height),IPL_DEPTH_8U, 1);
frame_gray_last = cvCreateImage(cvSize(frame->width,frame->height),IPL_DEPTH_8U, 1);
m_out_image = cvCreateImage(cvSize(frame->width,frame->height),IPL_DEPTH_8U, 1);
m_out_image_copy = cvCreateImage( cvSize(frame->width,frame->height),IPL_DEPTH_8U, 1 );
cvCvtColor(frame,frame_gray,CV_RGB2GRAY);
cvCvtColor(frame_last,frame_gray_last,CV_RGB2GRAY);
cvAbsDiff(frame_gray,frame_gray_last,m_out_image);
//cvThreshold(m_out_image,m_out_image,128, 255,CV_THRESH_BINARY);
//将处理后的图像写出到第二个图像中
if( m_out_image_copy->origin == IPL_ORIGIN_TL )
{
cvCopy( m_out_image, m_out_image_copy, 0 );
}
else
{
cvFlip( m_out_image, m_out_image_copy, 0 );
}
frame_last = cvCreateImage(cvSize(frame->width,frame->height),IPL_DEPTH_8U, frame->nChannels);
cvCopy(frame,frame_last);
cvShowImage("差分",m_out_image_copy);
cvShowImage("result",frame);
cvReleaseImage( &m_out_image_copy );
cvReleaseImage( &frame_gray_last );
cvReleaseImage( &frame_gray );
if( cvWaitKey( 20 ) >= 0 )
{
break;
}
}
}
cvWaitKey();
cvReleaseImage( &m_out_image );
cvReleaseImage( &frame_last );
cvReleaseImage( &frame );
cvReleaseCapture( &capture );
cvDestroyWindow("result");
cvDestroyWindow("差分");
return 0;
}
#endif