IplImage::origin的认识

origin是有作用的，而且直接确定了在一张图片width*Height个像素的排列顺序。

Windows 状态下，摄像头取得的数据，origin=1。原点在左下。IplImage::ImageData的一个点是左下的数据。验证代码如下：

 

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// 像素顺序.cpp : Defines the entry point for the console application. // #include "stdafx.h" /************************************************** * 背景建模，运动物体检测 * **************************************************/ /*********************************************************************** * OpenCV example * By Shiqi Yu 2006 ***********************************************************************/ #include <stdio.h> #include <cv.h> #include <cxcore.h> #include <highgui.h> #pragma comment (lib, "cxcore.lib") #pragma comment (lib, "highgui.lib") #pragma comment (lib, "cv.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; IplImage* pImage = 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); cvNamedWindow("Clone Video",1); //使窗口有序排列 cvMoveWindow("video", 30, 0); cvMoveWindow("background", 360, 0); cvMoveWindow("foreground", 690, 0); if( argc > 2 ) { fprintf(stderr, "Usage: bkgrd [video_file_name]/n"); return -1; } //打开摄像头 if (argc ==1) if( !(pCapture = cvCaptureFromCAM(-1))) { fprintf(stderr, "Can not open camera./n"); return -2; } //打开视频文件 if(argc == 2) if( !(pCapture = cvCaptureFromFile(argv[1]))) { fprintf(stderr, "Can not open video file %s/n", argv[1]); 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 printf("pFrame %d %d %d origin = %d/n",(uchar)pFrame->imageData[0],(uchar)pFrame->imageData[1],(uchar)pFrame->imageData[2],pFrame->origin); cvShowImage("video", pFrame); if (pImage){ cvReleaseImage(&pImage); } pImage = cvCloneImage(pFrame); printf("pImage %d %d %d origin = %d/n",(uchar)pImage->imageData[0],(uchar)pImage->imageData[1],(uchar)pImage->imageData[2],pImage->origin); cvShowImage("Clone Video",pImage); cvShowImage("background", pBkImg); cvFlip(pFrImg); printf("pFrImg %d %d %d origin = %d/n",(uchar)pFrImg->imageData[0],(uchar)pFrImg->imageData[1],(uchar)pFrImg->imageData[2],pFrImg->origin); 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(2) >= 0 ) break; } } //销毁窗口 cvDestroyWindow("video"); cvDestroyWindow("background"); cvDestroyWindow("foreground"); cvDestroyWindow("Clone Video"); //释放图像和矩阵 cvReleaseImage(&pFrImg); cvReleaseImage(&pBkImg); cvReleaseImage(&pImage); cvReleaseMat(&pFrameMat); cvReleaseMat(&pFrMat); cvReleaseMat(&pBkMat); cvReleaseCapture(&pCapture); return 0; }