OpenCV实现平均背景法

 /* 平均背景法 */ #include "highgui.h" #include "cv.h" #include #include //为不同的临时指针图像和统计属性创建指针 //Float, 3-channel images IplImage* IavgF, * IdiffF, * IprevF, * IhiF, *IlowF; IplImage* Iscratch, *Iscratch2; //Float 1-channel images IplImage* Igray1, * Igray2, * Igray3; IplImage* Ilow1, * Ilow2, * Ilow3; IplImage* Ihi1, *Ihi2, * Ihi3; //Byte, 1-channel image IplImage* Imask; IplImage* Imaskt; //Counts number of images learned for averaging later. float Icount; // 创建一个函数来给需要的所有临时图像分配内存 //为了方便，我们传递一幅图像(来自视频)作为大小参考来分配临时图像 void AllocateImages(IplImage* I) { CvSize sz = cvGetSize(I); IavgF = cvCreateImage(sz, IPL_DEPTH_32F, 3); IdiffF = cvCreateImage(sz, IPL_DEPTH_32F,3); IprevF = cvCreateImage(sz, IPL_DEPTH_32F,3); IhiF = cvCreateImage(sz, IPL_DEPTH_32F, 3); IlowF = cvCreateImage(sz, IPL_DEPTH_32F,3); Ilow1 = cvCreateImage(sz, IPL_DEPTH_32F,1); Ilow2 = cvCreateImage(sz, IPL_DEPTH_32F,1); Ilow3 = cvCreateImage(sz, IPL_DEPTH_32F,1); Ihi1 = cvCreateImage(sz, IPL_DEPTH_32F,1); Ihi2 = cvCreateImage(sz, IPL_DEPTH_32F,1); Ihi3 = cvCreateImage(sz, IPL_DEPTH_32F,1); cvZero(IavgF); cvZero(IdiffF); cvZero(IprevF); cvZero(IhiF); cvZero(IlowF); Icount = 0.00001; Iscratch = cvCreateImage(sz, IPL_DEPTH_32F,3); Iscratch2 = cvCreateImage(sz, IPL_DEPTH_32F,3); Igray1 = cvCreateImage(sz, IPL_DEPTH_32F,1); Igray2 = cvCreateImage(sz, IPL_DEPTH_32F,1); Igray3 = cvCreateImage(sz, IPL_DEPTH_32F,1); Imask = cvCreateImage(sz, IPL_DEPTH_8U, 1); Imaskt = cvCreateImage(sz, IPL_DEPTH_8U,1); cvZero(Iscratch); cvZero(Iscratch2); } //学习累积背景图像和每一帧图像差值的绝对值 // Learn the background statistics for one more frame // I is a color sample of the background, 3-channel, 8u void accumulateBackground(IplImage *I) { static int first = 1; cvCvtScale(I, Iscratch, 1, 0); if(!first) { cvAcc(Iscratch,IavgF); cvAbsDiff(Iscratch, IprevF, Iscratch2); cvAcc(Iscratch2,IdiffF); Icount += 1.0; } first = 0; cvCopy(Iscratch, IprevF); } //setHighThreshold和setLowThreshold都是基于每一帧图像平均绝对差设置阈值的有效函数 void setHighThreshold(float scale) { cvConvertScale(IdiffF, Iscratch, scale); cvAdd(Iscratch, IavgF, IhiF); cvSplit(IhiF, Ihi1, Ihi2, Ihi3, 0); } void setLowThreshold(float scale) { cvConvertScale(IdiffF, Iscratch, scale); cvSub(IavgF, Iscratch, IlowF); cvSplit(IlowF, Ilow1, Ilow2, Ilow3, 0); } //当积累了足够多的帧图像之后，就将其转化为一个背景的统计模型 //计算每一个像素的均值和方差观测 void createModelsfromStats() { cvConvertScale(IavgF, IavgF, (double)(1.0/Icount)); cvConvertScale(IdiffF, IdiffF, (double)(1.0/Icount)); //Make sure diff is always something cvAddS(IdiffF, cvScalar(1.0, 1.0, 1.0), IdiffF); setHighThreshold(7.0); setLowThreshold(6.0); } //有了背景模型，同时给出了高，低阈值，就能用它将图像分割为前景和背景 // Create a binary: 0,255 mask where 255 means foregrond pixel // I Input image, 3-channel, 8u //Imask void backgroundDiff(IplImage* I) { cvCvtScale(I, Iscratch, 1, 0); cvSplit(Iscratch, Igray1, Igray2, Igray3, 0); //Channel 1 cvInRange(Igray1, Ilow1, Ihi1, Imask); //Channel 2 cvInRange(Igray2, Ilow2, Ihi2, Imaskt); cvOr(Imask, Imaskt, Imask); //Channel 3 cvInRange(Igray3, Ilow3, Ihi3, Imaskt); cvOr(Imask, Imaskt, Imask); //Finally, invert the result cvSubRS(Imask, cvScalar(255), Imask); } //完成背景建模后， 释放内存 void DeallocateImage() { cvReleaseImage(&IavgF); cvReleaseImage(&IdiffF); cvReleaseImage(&IprevF); cvReleaseImage(&IhiF); cvReleaseImage(&IlowF); cvReleaseIm<em style="color:transparent">来源gao.dai.ma.com搞@代*码网</em>age(&Ilow1); cvReleaseImage(&Ilow2); cvReleaseImage(&Ilow3); cvReleaseImage(&Iscratch); cvReleaseImage(&Iscratch2); cvReleaseImage(&Igray1); cvReleaseImage(&Igray2); cvReleaseImage(&Igray3); cvReleaseImage(&Imaskt); } //主函数 int main() { CvCapture* capture = cvCreateFileCapture("tree.avi"); if(!capture) { return -1; } cvNamedWindow("win1"); cvNamedWindow("win2"); IplImage* rawImage = cvQueryFrame(capture); cvShowImage("win1", rawImage); AllocateImages(rawImage); int i = 0; while(1) { if(i <= 30) { accumulateBackground(rawImage); if(i == 30) { createModelsfromStats(); } } else { backgroundDiff(rawImage); } cvShowImage("win2", Imask); if(cvWaitKey(33) == 27) { break; } if(!(rawImage = cvQueryFrame(capture))) { break; } cvShowImage("win1", rawImage); if(i == 56 || i == 63) cvWaitKey(); i = i+1; } DeallocateImage(); return 0; }