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1、 The Learning of OpenCVHere contains just the exercises in book Learning OpenCV and of course I believe there is better solution for them.problems: 1. If you set cvSetImageCOI, dont forget to set it back with parameter 0, otherwise you may end up with single channel.2. If you get your IplImage from
2、cvCapture, then do NOT release it as it is not created by you!3. There is some memory allocation in cvSubImageHeader, and do NOT forget to release them. 4. I tried to erase my drawing lines by xor it again, but it seems not working by using cvGetRow. Maybe it is because I mess up with cvSetImageROI
3、without reset it. So, I just use cvCopy to overwrite it.5. When you draw your rectangle of some width of line, be careful that the rectangle is bigger than that width of line.6. The color sequence in bytes order is BGR. The following are exercises in chapter 4./#include #include #include #include #i
4、nclude #include #include #include #pragma comment(lib, cvd.lib)#pragma comment(lib, cxcored.lib)#pragma comment(lib, highguid.lib)CvFont myfont = cvFont(1, 2);char* szCombineName = combine image;bool bMouseButtonDown = false;int x = 0, y = 0;void doDrawing(IplImage* pImage)char buffer256;int winX =
5、0, winY = 0;if (bMouseButtonDown)winX = x;winY = y;sprintf(buffer, mouse click at %d,%d, x, y);cvPutText(pImage, buffer, cvPoint(winX, winY), &myfont, cvScalar(255,0,0);void myMouseCallback(int event, int myx, int myy, int flag, void* pUser)switch (event)case CV_EVENT_LBUTTONDOWN:bMouseButtonDown =
6、true;x = myx;y = myy;break;case CV_EVENT_LBUTTONUP:bMouseButtonDown = false;break;void exercise1()char* szVideoName = e:mytest.avi;char* szWindowName = my video;char* szGrayName = gray image;char* szCannyName = canny image;CvCapture* pCapture = NULL;IplImage* pImage = NULL;IplImage* pGrayImg = NULL;
7、IplImage* pCannyImg = NULL;IplImage* pCombineImg = NULL;IplImage* pSub1= NULL;IplImage* pSub2= NULL;IplImage* pSub3= NULL;int nWidth = 0, nHeight = 0;cvNamedWindow(szWindowName);cvNamedWindow(szGrayName);cvNamedWindow(szCannyName);cvNamedWindow(szCombineName);pCapture = cvCreateFileCapture(szVideoNa
8、me);if (pCapture)nWidth = (int) cvGetCaptureProperty(pCapture, CV_CAP_PROP_FRAME_WIDTH);nHeight = (int) cvGetCaptureProperty(pCapture, CV_CAP_PROP_FRAME_HEIGHT);pGrayImg = cvCreateImage(cvSize(nWidth, nHeight), 8, 1);pCannyImg = cvCreateImage(cvSize(nWidth, nHeight), 8, 1);pCombineImg = cvCreateImag
9、e(cvSize(nWidth, 3*nHeight), 8, 1);pSub1 = cvCreateImageHeader(cvSize(nWidth, nHeight), 8, 1);pSub2 = cvCreateImageHeader(cvSize(nWidth, nHeight), 8, 1);pSub3 = cvCreateImageHeader(cvSize(nWidth, nHeight), 8, 1);pSub1-origin = pCombineImg-origin;pSub2-origin = pCombineImg-origin;pSub3-origin = pComb
10、ineImg-origin;pSub1-widthStep = pCombineImg-widthStep;pSub2-widthStep = pCombineImg-widthStep;pSub3-widthStep = pCombineImg-widthStep;pSub1-imageData = pCombineImg-imageData;pSub2-imageData = pCombineImg-imageData + nHeight*pCombineImg-widthStep;pSub3-imageData = pCombineImg-imageData + nHeight*2*pC
11、ombineImg-widthStep;cvSetMouseCallback(szCombineName, myMouseCallback, pCombineImg);/cvResizeWindow(szCombineName, pCombineImg-width, pCombineImg-height);doif (cvWaitKey(15) = 27)break;pImage = cvQueryFrame(pCapture);if (pImage)cvConvertImage(pImage, pGrayImg, 0);cvCanny(pGrayImg, pCannyImg, 1, 2, 5
12、);/cvShowImage(szWindowName, pImage);/cvShowImage(szGrayName, pGrayImg);/cvShowImage(szCannyName, pCannyImg);cvSetImageCOI(pImage, 1);cvCopy(pImage, pSub1, NULL);cvCopy(pGrayImg, pSub2, NULL);cvCopy(pCannyImg, pSub3, NULL);cvPutText(pSub1, szWindowName, cvPoint(nWidth/2, nHeight/2), &myfont, cvScala
13、r(255,0,0);cvPutText(pSub2, szGrayName, cvPoint(nWidth/2, nHeight/2), &myfont, cvScalar(255,0,0);cvPutText(pSub3, szCannyName, cvPoint(nWidth/2, nHeight/2), &myfont, cvScalar(255,0,0);doDrawing(pCombineImg);cvShowImage(szCombineName, pCombineImg);cvSetImageCOI(pImage, 0);while (true);/ do NOT releas
14、e pImage because it is only retrieved from capture/cvReleaseImage(&pImage);cvReleaseImageHeader(&pSub1);cvReleaseImageHeader(&pSub2);cvReleaseImageHeader(&pSub3);cvReleaseImage(&pGrayImg);cvReleaseImage(&pCannyImg);cvReleaseImage(&pCombineImg);cvReleaseCapture(&pCapture);cvDestroyAllWindows();void m
15、yMouseOnClick(int event, int x, int y, int flag, void* pUser)char buffer256;CvFont myFont = cvFont(2, 2);IplImage* pImage = (IplImage*)pUser;char* ptr = NULL;unsigned char r=0, g=0, b=0;switch (event)case CV_EVENT_LBUTTONDOWN:ptr = pImage-imageData + y*pImage-widthStep + x * pImage-depth* pImage-nCh
16、annels/8;r = ptr0;g = ptr1;b = ptr2;sprintf(buffer, rgb %d,%d,%d, r,g,b);cvPutText(pImage, buffer, cvPoint(x, y), &myFont, cvScalar(255,0,0);break;void exercise2()IplImage* pImage = NULL; /, *pCloneImage = NULL;pImage = cvLoadImage(mytest.jpg);/pCloneImage = cvCloneImage(pImage);cvNamedWindow(mytest
17、);cvSetMouseCallback(mytest, myMouseOnClick, pImage);docvShowImage(mytest, pImage);if (cvWaitKey(1000)=27)break;while (true);cvReleaseImage(&pImage);cvDestroyWindow(mytest);#define HistogramWidth 48#define HistogramHeight 800IplImage* pImage = NULL, *pCloneImage = NULL, *pHistImage= NULL;CvRect rect
18、 = cvRect(0,0,0,0);bool bStart = false;#if 0void eraseFrame()CvMat vecSrc, vecDst;cvSetImageROI(pImage, rect);cvSetImageROI(pCloneImage, rect);cvGetRow(pImage, &vecSrc, 0);cvGetRow(pCloneImage, &vecDst, 0);cvCopy(&vecSrc, &vecDst);cvGetRow(pImage, &vecSrc, rect.height-1);cvGetRow(pCloneImage, &vecDs
19、t, rect.height-1);cvCopy(&vecSrc, &vecDst);cvGetCol(pImage, &vecSrc, 0);cvGetCol(pCloneImage, &vecDst, 0);cvCopy(&vecSrc, &vecDst);cvGetCol(pImage, &vecSrc, rect.width-1);cvGetCol(pCloneImage, &vecDst, rect.width-1);cvCopy(&vecSrc, &vecDst);cvResetImageROI(pImage);cvResetImageROI(pCloneImage);#elsev
20、oid eraseFrame()cvSetImageROI(pImage, rect);cvSetImageROI(pCloneImage, rect);cvCopy(pCloneImage, pImage);cvResetImageROI(pImage);cvResetImageROI(pCloneImage);#endif#define LINE_WIDTH 1void drawFrame()cvRectangle(pImage, cvPoint(rect.x, rect.y), cvPoint(rect.x+rect.width-1, rect.y+rect.height-1), cvS
21、calarAll(255), LINE_WIDTH);/cvLine(pImage, cvPoint(rect.x, rect.y), cvPoint(rect.x+rect.width, rect.y+rect.height), cvScalarAll(255), LINE_WIDTH);void drawHistogram()char* ptr = NULL, *pRow = NULL, *pCol = NULL;char buffer32;int hist38= 0;int index = 0;int nPixWidth = 0;int r, c, i, nOffset = 0;int
22、x = 0 , y = 0;CvFont myFont = cvFont(1,1);int nMax = 0, nScale=1;nPixWidth = pCloneImage-nChannels*pCloneImage-depth/8;ptr = pCloneImage-imageData + rect.y*pCloneImage-widthStep + rect.x*nPixWidth;pRow = ptr;for (r = 0; r rect.height; r +)pCol = pRow;for (c = 0; c rect.width; c +)for (i =0; i nMax)n
23、Max = histiindex;pCol += nPixWidth;pRow += pCloneImage-widthStep;cvSet(pHistImage, cvScalarAll(255);y = HistogramHeight;nScale = HistogramHeight / HistogramHeight;if (nScale = 0)nScale = 1;for (c = 0; c 8; c +)for (i = 0; i LINE_WIDTH & h LINE_WIDTH)if (w != rect.width | h != rect.height)if (rect.wi
24、dth 0 & rect.height 0)eraseFrame();/rect.width = w;rect.height = h;/cvSetImageROI(pImage, rect);/cvSetImageROI(pCloneImage, rect);/cvSet(pImage, cvScalarAll(255);drawFrame();/cvResetImageROI(pImage);/cvResetImageROI(pCloneImage);break;case CV_EVENT_LBUTTONDOWN:if (rect.width 0 & rect.height 0)cvSetI
25、mageROI(pImage, rect);cvSetImageROI(pCloneImage, rect);cvCopy(pCloneImage, pImage);cvResetImageROI(pImage);cvResetImageROI(pCloneImage);/rect.x = x;rect.y = y;rect.width = rect.height = 0;bStart = true;break;case CV_EVENT_LBUTTONUP:if (rect.width 0 & rect.height 0)cvSetImageROI(pImage, rect);cvSet(p
26、Image, cvScalarAll(255);cvResetImageROI(pImage);drawHistogram();/bStart = false;break;void exercise3()pImage = cvLoadImage(mytest.jpg);pCloneImage = cvCloneImage(pImage);cvNamedWindow(histogram);cvNamedWindow(mytest);cvSetMouseCallback(mytest, myMouseCallback3, NULL);pHistImage = cvCreateImage(cvSiz
27、e(8 * HistogramWidth * 3, HistogramHeight+200), 8, 3);docvShowImage(mytest, pImage);if (cvWaitKey(100)=27)break;while (true);cvReleaseImage(&pImage);cvReleaseImage(&pCloneImage);cvDestroyWindow(mytest);int APIENTRY WinMain(HINSTANCE hInstance,HINSTANCE hPrevInstance,LPSTR lpCmdLine,int nCmdShow)exer
28、cise3();/myTest();return 0;/There is a problem that I dont know how to control the program flow. For example, I setup two cvWaitKey because I place one in my main program and another one in the while loop of playing video. You see, if you dont place a cvWaitKey inside the video playing loop, then th
29、ere is simply no redrawing of window. Just image there is no overlapping threads to either decode video or draw window.The following is a simple program acting as an video player(exercise4)#include #include #include #include #include #include #include #include #pragma comment(lib, cvd.lib)#pragma co
30、mment(lib, cxcored.lib)#pragma comment(lib, highguid.lib)int g_nProgress = 0;int g_nPause = 0;int g_nWait = 0;CvCapture* pCapture = NULL;int nValue = -1;char* szWindowName = myplayer;void switchCallback4(int nPos)double fPos = 0.0;fPos = (double)nPos / (double)10;if (pCapture)cvSetCaptureProperty(pC
31、apture, CV_CAP_PROP_POS_AVI_RATIO, fPos);void myPlayer()IplImage* pImage = NULL;doif (g_nPause = 0)break;pImage = cvQueryFrame(pCapture);if (pImage)cvShowImage(szWindowName, pImage);nValue = cvWaitKey(50);while (nValue = -1);void switchCallback5(int nPos)if (nPos = 1)myPlayer();void exercise4()pCapt
32、ure = cvCreateFileCapture(mytest.avi);if (pCapture)cvNamedWindow(szWindowName);cvCreateTrackbar(progress, szWindowName, &g_nProgress, 10, switchCallback4);cvCreateTrackbar(pause, szWindowName, &g_nPause, 1, switchCallback5);doif (cvWaitKey(0) = 27)break;while(true);cvReleaseCapture(&pCapture);cvDest
33、royWindow(szWindowName);int APIENTRY WinMain(HINSTANCE hInstance,HINSTANCE hPrevInstance,LPSTR lpCmdLine,int nCmdShow)exercise4();return 0;chapter 5 exercises:#include #include #include #include #include #include #include #include #pragma comment(lib, cvd.lib)#pragma comment(lib, cxcored.lib)#pragma
34、 comment(lib, highguid.lib)void exercise1()char* szWindowName = loadImage, simpleImage, simpleNoScale, NoMedian, Guassian, bilateral;IplImage* pImage = NULL, *pSimpleImg = NULL, *pNoScaleImg = NULL, *pMedianImg = NULL, *pGaussianImg = NULL, *pBilateralImg = NULL;int i = 0;for (i = 0; i width, pImage
35、-height), pImage-depth, pImage-nChannels);pNoScaleImg = cvCreateImage(cvSize(pImage-width, pImage-height), IPL_DEPTH_16S, pImage-nChannels);pMedianImg = cvCreateImage(cvSize(pImage-width, pImage-height), pImage-depth, pImage-nChannels);pGaussianImg = cvCreateImage(cvSize(pImage-width, pImage-height)
36、, pImage-depth, pImage-nChannels);pBilateralImg = cvCreateImage(cvSize(pImage-width, pImage-height), pImage-depth, pImage-nChannels);cvSmooth(pImage, pSimpleImg, CV_BLUR, 5,5, 5,5);cvSmooth(pImage, pNoScaleImg, CV_BLUR_NO_SCALE,11,11, 32,0.5);cvSmooth(pImage, pMedianImg, CV_MEDIAN,5,5, 5,5);cvSmooth
37、(pImage, pGaussianImg, CV_GAUSSIAN,5,5, 5,5);cvSmooth(pImage, pBilateralImg, CV_BILATERAL, 3,3,0.01, 0.003);cvShowImage(szWindowName0, pImage);cvShowImage(szWindowName1, pSimpleImg);cvShowImage(szWindowName2, pNoScaleImg);cvShowImage(szWindowName3, pMedianImg);cvShowImage(szWindowName4, pGaussianImg);cvShowImage(szWindowName5, pBilateralImg);cvWaitKey(0);cvReleaseImage(&pImage);cvReleaseImage(&pSimpleImg);cvReleaseImage(&pNoScaleImg);
