三帧差分.docx

1、三帧差分这几天研究了下三帧差法做物体检测。 三帧差法的具体算法如下。 提取连续的三帧图像，I(k-1),I(k),I(k+1)。(1)d(k,k-1) x,y = | I(k)x,y - I(k-1)x,y |; d(k,k+1)x,y = | I(k+1)x,y - I(k)x,y |; (2)b(k,k-1)x,y = 1; if d(k,k-1) x,y = T;b(k,k-1)x,y =0; if d(k,k-1) x,y= T; b(k+1,k)x,y =0 if d(k+1,k) x,y T;(3)B(k)x,y = 1 ; if b(k,k-1)x,y & b(k+1,k)x,y

2、 = 1 ;B(k)x,y =0 ; if b(k,k-1)x,y & b(k+1,k)x,y =0 ; 到了这里，比较关键的就是第2步的阈值T的选取问题，单纯用otsu算法分割貌似效果不太好，如果手动设置一个较小的值（如10）效果还可以，但手动设置有一定的限制性。接下来要研究局部阈值的选取。 用otsu取阈值实现的一个三分差法代码。效果不是很好。#include highgui.h#include cv.h#include cxcore.h#include cvaux.h#include #include #include #include #include #include #includ

3、e #include using namespace std;/#pragma comment(lib, highgui200.lib)/#pragma comment(lib, cv200.lib)/#pragma comment(lib, cxcore200.lib)/#pragma comment(lib, cvaux200.lib)#define GET_IMAGE_DATA(img, x, y) (uchar*)(img-imageData + img-widthStep * (y)xint T = 10;int Num300;int Sum300;void InitPixel(Ip

4、lImage * img, int &_low, int &_top) memset(Num,0,sizeof(Num); memset(Sum,0,sizeof(Sum); _low = 255; _top = 0; for(int i = 0;i height;i+) for(int j = 0;j width;j+) int temp = (uchar*)(img-imageData + img-widthStep*i)j; if(temp _top) _top = temp; Numtemp += 1; for(int i = 1 ; i height*img-width; InitP

5、ixel(img,_low,_top); float max_otsu = 0; mbest = 0; if( _low = _top) mbest = _low; else for(int i = _low; i max_otsu) mbest = i; max_otsu = g; return mbest;int main() int ncount=0; IplImage *image1=NULL; IplImage *image2=NULL; IplImage *image3=NULL; IplImage *Imask =NULL; IplImage *Imask1=NULL; IplI

6、mage *Imask2=NULL; IplImage *Imask3=NULL; IplImage *mframe=NULL; CvCapture *capture = cvCreateFileCapture(E:MotionIndoorGTTest2.avi); /CvCapture *capture = cvCreateCameraCapture(0); cvNamedWindow(src); cvNamedWindow(dst); cvNamedWindow(Imask1); cvNamedWindow(Imask2); cvNamedWindow(Imask3); /cvCreate

7、Trackbar(T,dst,&T,255,0); while(mframe=cvQueryFrame(capture) DWORD start=GetTickCount(); if(ncount1000000000) ncount=100; ncount+=1; if(ncount=1) image1=cvCreateImage(cvGetSize(mframe),IPL_DEPTH_8U,1); image2=cvCreateImage(cvGetSize(mframe),IPL_DEPTH_8U,1); image3=cvCreateImage(cvGetSize(mframe),IPL

8、_DEPTH_8U,1); Imask =cvCreateImage(cvGetSize(mframe),IPL_DEPTH_8U,1); Imask1=cvCreateImage(cvGetSize(mframe),IPL_DEPTH_8U,1); Imask2=cvCreateImage(cvGetSize(mframe),IPL_DEPTH_8U,1); Imask3=cvCreateImage(cvGetSize(mframe),IPL_DEPTH_8U,1); cvCvtColor(mframe,image1,CV_BGR2GRAY); if(ncount=2) cvCvtColor

9、(mframe,image2,CV_BGR2GRAY); if(ncount=3) if(ncount=3) cvCvtColor(mframe,image3,CV_BGR2GRAY); else cvCopy(image2,image1); cvCopy(image3,image2); cvCvtColor(mframe,image3,CV_BGR2GRAY); cvAbsDiff(image2,image1,Imask1); cvAbsDiff(image3,image2,Imask2); /cvShowImage(Imask1,Imask1); /cvShowImage(Imask2,I

10、mask2); int mbest1 = otsu(Imask1); cvSmooth(Imask1, Imask1, CV_MEDIAN); cvThreshold(Imask1,Imask1,mbest1, 255, CV_THRESH_BINARY); int mbest2 = otsu(Imask2); cvSmooth(Imask2,Imask2, CV_MEDIAN); cvThreshold(Imask2,Imask2,mbest2, 255, CV_THRESH_BINARY); coutmbest1 mbest2endl; cvAnd(Imask1,Imask2,Imask)

11、; /*cvErode(Imask, Imask); cvDilate(Imask,Imask);*/ DWORD finish=GetTickCount(); / coutfinish-startmsendl; cvShowImage(src,image2); cvShowImage(dst,Imask); char c = cvWaitKey(30); if(c=27) break; return 0;#include stdafx.h#include cv.h#include cxcore.h#include highgui.h#include stdio.hint main(int a

12、rgc, _TCHAR* argv) IplImage* pFrame = NULL; IplImage* pFrImg1 = NULL; IplImage* pFrImg2 = NULL; IplImage* pFrImg3 = NULL; IplImage* result1 = NULL; IplImage* result2 = NULL; IplImage* result = NULL; IplImage* tempImg1 = NULL; CvSize size; CvMat* pFrMat1 = NULL; CvMat* pFrMat2 = NULL; CvMat* pFrMat3

13、= NULL; CvMat* reMat1 = NULL; CvMat* reMat2 = NULL; CvMat* reMat = NULL; CvMat* tempMat1 = NULL; CvCapture* pCapture = NULL; int nFrmNum = 0; char* reWin = effect + nFrmNum; cvNamedWindow(video, 1); cvNamedWindow(effect, 1); cvMoveWindow(video, 0, 0); cvMoveWindow(effect, 400, 400); if( argc != 1 )

14、fprintf(stderr, Usage: bkgrd n); return -1; if( !(pCapture = cvCaptureFromFile(F:仿真结果B vector.avi) fprintf(stderr, Can not open video file %sn, F:仿真结果B vector.avi); return -2; while(pFrame = cvQueryFrame( pCapture ) nFrmNum+; if ( nFrmNum 500) nFrmNum = 0; break; printf(视频帧数：%dn,nFrmNum); cvSetCaptu

15、reProperty( pCapture, CV_CAP_PROP_POS_FRAMES, 0 ); /第一帧 pFrame = cvQueryFrame( pCapture ); if(nFrmNum2) pFrImg1 = cvCreateImage(cvGetSize(pFrame), IPL_DEPTH_8U, 1); pFrImg2 = cvCreateImage(cvGetSize(pFrame), IPL_DEPTH_8U, 1); pFrImg3 = cvCreateImage(cvGetSize(pFrame), IPL_DEPTH_8U, 1); result1 = cvC

16、reateImage(cvGetSize(pFrame), IPL_DEPTH_8U, 1); result2 = cvCreateImage(cvGetSize(pFrame), IPL_DEPTH_8U, 1); result = cvCreateImage(cvGetSize(pFrame), IPL_DEPTH_8U, 1); pFrMat1 = cvCreateMat(pFrame-height, pFrame-width, CV_8UC1); pFrMat2 = cvCreateMat(pFrame-height, pFrame-width, CV_8UC1); pFrMat3 =

17、 cvCreateMat(pFrame-height, pFrame-width, CV_8UC1); reMat1 = cvCreateMat(pFrame-height, pFrame-width, CV_8UC1); reMat2 = cvCreateMat(pFrame-height, pFrame-width, CV_8UC1); reMat = cvCreateMat(pFrame-height, pFrame-width, CV_8UC1); size = cvSize(pFrame-width, pFrame-height); tempImg1 = cvCreateImage(

18、 cvSize(size.width & -2)/2, (size.height & -2)/2), 8, 1 ); else printf(帧数小于3！n); return -1; /先读取两帧 cvCvtColor(pFrame, pFrImg1, CV_BGR2GRAY); cvConvert(pFrImg1, pFrMat1); pFrame = cvQueryFrame( pCapture ); cvCvtColor(pFrame, pFrImg2, CV_BGR2GRAY); cvConvert(pFrImg2, pFrMat2); int count = 2; while(pFr

19、ame = cvQueryFrame( pCapture ) count+; cvCvtColor(pFrame, pFrImg3, CV_BGR2GRAY); cvConvert(pFrImg3, pFrMat3); cvSmooth(pFrMat1, pFrMat1, CV_GAUSSIAN , 3, 1); cvSmooth(pFrMat2, pFrMat2, CV_GAUSSIAN , 3, 1); cvSmooth(pFrMat3, pFrMat3, CV_GAUSSIAN , 3, 1); /当前帧跟前一帧相减 cvAbsDiff(pFrMat2, pFrMat1, reMat1)

20、; cvAbsDiff(pFrMat3, pFrMat2, reMat2); /二值化前景图 cvThreshold(reMat1, result1, 60.0, 255.0, CV_THRESH_BINARY); cvThreshold(reMat2, result2, 60.0, 255.0, CV_THRESH_BINARY); /cvAdaptiveThreshold( reMat1, result1, 255, CV_ADAPTIVE_THRESH_MEAN_C, CV_THRESH_BINARY, 5, 5 ); /cvAdaptiveThreshold( reMat2, resu

21、lt2, 255, CV_ADAPTIVE_THRESH_MEAN_C, CV_THRESH_BINARY, 5, 5 ); /两个帧差值相与 cvAnd(result1,result2,result,0); /使用Gaussian金字塔分解对输入图像向下采样，输出图像的高度和宽度应是输入图像的一半 cvPyrDown(result, tempImg1, 7 ); /对输入图像进行膨胀 cvDilate(result, result, 0, 1); /使用Gaussian金字塔分解对输入图像向上采样，输出图像的高度和宽度应是输入图像的2倍 cvPyrUp(tempImg1, result, 7

22、 ); /cvErode(result, result, 0, 1); /cvDilate(result, result, 0, 1); /cvPyrDown(result, tempImg1, 7 ); /cvPyrUp(tempImg1, result, 7 ); cvErode(result, result, 0, 3); cvDilate(result, result, 0, 3); /翻转图像，使其正立显示 cvFlip(result, NULL, 0); cvShowImage(video, pFrame); cvShowImage(effect, result); cvCopy(

23、pFrMat2, pFrMat1, NULL); cvCopy(pFrMat3, pFrMat2, NULL); if( cvWaitKey( 20 ) = 0 ) break; printf(nFrame = %dn, count); /销毁窗口 cvDestroyWindow(video); /cvDestroyWindow(reWin); cvDestroyWindow(effect); /释放图像和矩阵 cvReleaseImage(&pFrImg1); cvReleaseImage(&pFrImg2); cvReleaseImage(&result1); cvReleaseImage(&result2); cvReleaseImage(&result); cvReleaseImage(&tempImg1); cvReleaseMat(&pFrMat1); cvReleaseMat(&pFrMat2); cvReleaseMat(&reMat1); cvReleaseMat(&reMat2); cvReleaseMat(&reMat); cvReleaseCapture(&pCapture); return 0;