Chessboard Pdf Open Cv Github
Once the best scoring grid is found, we try and fit a chessboard to the points in unity grid space, then do one more refinement with opencv's findHomography and the final chessboard transform is shown as a red outline. Given a photo with a chess board in it, find the chessboard grid.
#Calibrating Your Camera In the ARToolKit software, default camera properties are contained in the camera parameter file camerapara.dat, that is read in each time an application is started. These parameters are sufficient for basic tracking for a wide range of different cameras. However, to get best tracking accuracy, particularly when looking directly onto a flat marker, it is important to calibrate your camera. Halo 2 Serial Number.
Using a calibrated camera improves tracking accuracy and reduces jitter. In the case of video see-through AR devices (goggles that are not optically see through that usually utilize stereo cameras), having calibrated cameras can help remove lens distortion in the displayed video image. Using a very simple camera calibration technique it is possible to generate a separate parameter file for the specific camera(s) that are being used. This page presents how to use the utility programs included with ARToolKit to calibrate your video camera. ###Set-Up Calibration works by capturing images of the pre-prepared calibration pattern with the camera. Two calibration pattern image files are provided by the ARToolKit SDK (path: downloaded ARToolKit SDK root directory/doc/patterns): 'Calibration chessboard (US Letter).pdf' 'Calibration chessboard (A4).pdf' Print the PDF file using a media size respective to the labeled PDF filename. Once printed, the pattern must be affixed to a flat surface.
The easiest means of doing this is to use a piece of thin very flat board (as might be obtained from a hardware store) and a dry glue. Using a millimeter rule, measure the size of the edges of the squares.
If printed without scaling, this distance will be exactly 30 mm. Other sizes can be used, as long as they are accurately known. Finally, set up your camera.
A calibration file is only valid for one focus setting of the camera (although it will still work at other focal lengths), so choose in advance the focus setting for the camera which will be used most often. This is especially important when your camera supports multiple aspect ratios. While the resolution need not be 1:1 with your camera calibration, the aspect ratio is extremely important. ###How it Works The image consists of a grid of black and white squares surrounded by a white border. When viewed through the camera lens, lens distortion causes the straight lines at the edges of the squares to appear curved. The calibcamera program uses the OpenCV library to locate the corners of the squares and then measures the spacing between the corners and uses this information to calculate the lens distortion.
The more images captured, and the more angles they are captured from, the lower the error in the distortion measurement. ####Executing the calibcamera Application Open a command prompt: Mac OS X or Linux: open a Terminal window or Windows: open the 'Run' prompt from the Start menu, in the 'Open:' textbox, type 'cmd' For the Android or iOS version of calibcamera, build and deploy the Android Studio, Eclipse or XCode project available in the respective platform project directory found directly under the root directory of the download ARToolKit SDK specific for the platform. Run the calibcamera application executable from the command prompt. Change the directory to the path: downloaded ARToolKit SDK root directory/bin. OS X or Linux command-line, type:./calibcamera Windows command-line, type: calibcamera.exe You will see output similar to this in your terminal: CHESSBOARDCORNERNUMX = 7 CHESSBOARDCORNERNUMY = 5 CHESSBOARDPATTERNWIDTH = 30.000000 CALIBIMAGENUM = 10 Video parameter: Using default video config. Image size (x,y) = (640,480) At this point, you should see the image from the camera appear.
#####Optional - Changing the Default Calibration Pattern Settings If you need to, the size of the calibration squares, the number of intermediate corners in horizontal and vertical directions (i.e. The number of rows minus 1 and the number of columns minus 1), and the number of calibration images captured can all be adjusted from the command line. Running the utility with the -help option will show the various command-line options for adjusting the default calibration settings.
Opencv Chessboard Detection
Failed to load latest commit information. README.md Learning OpenCV 3 INTRO This is the example code that accompanies Learning OpenCV 3 by Adrian Kaehler and Gary Bradski. Click the Download Zip button to the right to download example code. Visit the catalog page.
Chessboard Pdf Opencv Github Online
See an error? Report it, or simply fork and send us a pull request NOTES For default suggestions of how the run the code, it assumes you put your build directory under Learning-OpenCV-3examples directory. Thus, from the Learning-OpenCV-3examples directory: mkdir build cd build cmake.