OpenCV Open source C omputer V ision library By : Bahare Torkaman tr.bahareh@gmail.com

1. OpenCV Open source Computer Vision library By: BahareTorkaman tr.bahareh@gmail.com Fall 2010

2. General description • Open source computer vision library in C/C++ • Highlevelfunctions for computer vision and image processing • Both low and high level API • Optimized and intended for real-time applications • OpenCVmodules: • cv - Main OpenCV functions. • cvaux - Auxiliary (experimental) OpenCV functions. • cxcore - Data structures and linear algebra support. • highgui - GUI functions.

3. Resources • Official webpage: http://www.intel.com/technology/computing/opencv/ • Software download: http://sourceforge.net/projects/opencvlibrary/ • Books: • Learning OpenCV by Gary R. Bradski and Adrian Pisarevsky, O’Reilly (September 2008: First Edition)

4. Other webpages: http://www.cs.iit.edu/~agam/cs512/lect-notes/opencv-intro/opencv-intro.html http://www.site.uottawa.ca/~laganier/tutorial/opencv+directshow/cvision.htm http://opencv.willowgarage.com/documentation/cpp/index.html http://www.seas.upenn.edu/~bensapp/opencvdocs/ref/opencvref_cv.htm http://tech.groups.yahoo.com/group/OpenCV/messages http://opencv.willowgarage.com/wiki/ http://www.aishack.in/2010/02/capturing-images/ http://www.site.uottawa.ca/~laganier/tutorial/opencv+directshow/ http://www.sharifi.id.ir/2010/08/opencv-1.html

5. Installation OpenCV-2.1.0-win32-vs2008

6. Installation

7. Installation

8. Configuration

9. Configuration

10. Configuration

11. Configuration

12. Configuration

13. Configuration

14. Configuration

15. New project

16. New project

17. New project

18. New project

19. New project

20. Add library

21. Add library cv210.lib cvaux210.lib cxcore210.lib cxts210.lib highgui210d.lib ml210d.lib opencv_ffmpeg210d.lib cv210d.lib cvaux210d.lib cxcore210d.lib highgui210.lib ml210.lib opencv_ffmpeg210.lib

22. Tools  options  project and solutions  vc++ directories  • executable files  C:\OpenCV2.1\bin • Include files  C:\OpenCV2.1\include\opencv • Library files  C:\OpenCV2.1\lib • File  new project  win32  win32 console application  application settings empty project … project  add new item  c++ file(.cpp) • Project  properties configuration properties  linker  input  additional dependencies  • cv210.lib cvaux210.lib cxcore210.lib cxts210.lib highgui210d.lib ml210d.lib opencv_ffmpeg210d.lib cv210d.lib cvaux210d.lib cxcore210d.lib highgui210.lib ml210.lib opencv_ffmpeg210.lib

23. Load a picture #include <cv.h> #include <highgui.h> int main() { IplImage* img = cvLoadImage("C:\\orangeman.jpg"); cvNamedWindow("Original"); cvShowImage("Original", img); // We add processing code here cvWaitKey(0); cvReleaseImage(&img); return 0; } Load video Load camera cut a piece of image

24. #include <cv.h> #include <highgui.h> #include <cxcore.h> IplImage*frame = 0,*flip=0; intmain() { CvCapture* capture = 0; capture = cvCaptureFromFile("C:\\cap2.avi"); if(!capture) { printf("Could not initialize capturing...\n"); return -1; } while(true) {IplImage* frame = 0; frame = cvQueryFrame(capture); if(!frame) break; cvShowImage("video", frame); //cvFlip(frame,flip,0); cvShowImage("flip", frame); int c = cvWaitKey(20); if((char)c==27 ) break; } cvReleaseCapture(&capture); return 0; } Load a picture Load video Load camera cut a piece of image

25. #include <stdio.h> #include "cv.h" #include "highgui.h" IplImage *frame = 0,*capture= 0; int main( intargc, char **argv ) { CvCapture*capture =cvCreateCameraCapture(-1); IplImage *img; while(1) { img=cvQueryFrame(capture); if(!img)break; cvShowImage("Original", img); char c=cvWaitKey(33); if(c==27) break; } cvReleaseCapture(&capture); cvDestroyWindow("Original"); return 0; } Load a picture Load video Load camera cut a piece of image

26. #include <cv.h> #include <highgui.h> #include <cxcore.h> intmain() { CvCapture* capture = 0; capture = cvCaptureFromCAM(0); while(true) { IplImage* frame = 0; frame = cvQueryFrame(capture); if(!frame) break; cvShowImage("video", frame); cvSetImageROI( frame, cvRect( 10,60, 100,200 ) ); IplImage *img2 = cvCreateImage (cvGetSize(frame),frame->depth,frame->nChannels); cvCopy( frame, img2 ); cvShowImage("video2", img2); cvResetImageROI( frame ); intc = cvWaitKey(20); if((char)c==27 ) break; } cvReleaseCapture(&capture); return 0; } Load a picture Load video Load camera cut a piece of image

27. IplImage • This structure, called IplImage • OpenCV uses this structure to handle all kinds of images: single-channel, multichannel, integer-valued, floating-point-valued, et cetera. cvLoadImage() • is a high-level routine • determines the file format to be loaded based on the file name • automatically allocates the memory needed for the image data structure • can read a wide variety of image formats: BMP,DIB,JPEG, JPE,PNG,PBM,PGM,PPM,SR,RAS, and TIFF

28. cvNamedWindow() • Opens a window on the screen that can contain and display an image • provided by the HighGUIlibrary • Assigns a name to the window • The second argument to cvNamedWindow() defines window properties • 0 (the default value) : size of the window ↔ image size • image will be scaled to fit within the window • CV_WINDOW_AUTOSIZE : • the window will expand or contract automatically when an image is loaded so as to accommodate the image’s true size • image in the form of an IplImage* pointer

29. cvShowImage() • The cvShowImage() function requires that a named window already exist (created by cvNamedWindow()) cvWaitKey(0) • asks the program to stop and wait for a keystroke • argument: • positive : the program will wait for that number of milliseconds and then continue even if nothing is pressed • Zero or negative: the program will wait indefinitely for a keypress

30. cvReleaseImage( &img ) • OpenCVexpects a pointer to the IplImage* pointer for this operation • After the call is completed, the pointer img will be set to NULL • free the allocated memory cvDestroyWindow() • close the window • de-allocate any associated memory usage cvReleaseCapture(&capture) • free the memory associated with the CvCapture structure • close any open file handles to the AVI file

31. cvQueryFrame() • cvQueryFrame() takes as its argument a pointer to a CvCapture structure • grabs the next video frame into memory (memory that is actually part of the CvCapture structure) cvCreateCameraCapture (int index) • index: • If there is only one camera or it does not matter what camera to use -1 may be passed • this is important only when multiple cameras are available

32. cvFlip • Flip an array about a selected axis, around the x-axis, the y-axis, or both • the argument flip_mode is set to: • 0: image will be flipped around the x-axis • positive: image will be flipped around the y-axis • negative: image will be flipped around both axis cvSetImageROI • cvSetImageROI(src1, cvRect(x,y,width,height)); • Given a rectangular subregion of interest • “turn off ” by cvResetImageROI()

33. cvSetImageROI Int height (int x, int y) Int width

34. cvCopy • void cvCopy(const CvArr* src,CvArr* dst,constCvArr* mask = NULL); • Copy elements of one array to another • The cvCopy() function expects both arrays to have the same type, the same size, and the same number of dimensions cvGetSize • cvGetSize (const CvArr* arr ) • Get size of a two-dimensional array and return as CvSize

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36. OpenCV Open source Computer Vision library By: BahareTorkaman tr.bahareh@gmail.com Fall 2010