Point your laptop webcam at a piece of paper and the program will stretch the writable area over the whole screen.
GitHub : github.com/kacpertopol/cam_board
Print to_print/a4.pdf or to_print/a4.svg on A4 paper. The small circle marks the top left part of the page. If the aspect ratio of your webcam is different from 16:9 or you want to use paper with a different size see setting up the page with markers
Setup web cam
Tilt your webcam so that all 4 ARUCO markers are in its field of view.
IMPORTANT: To use the script with Zoom, Skype, MS Teams, … Disable the camera in these programs first, before running the script. Otherwise, a “camera busy” error will be thrown.
In the terminal navigate to the cam_board directory.
To launch the script:
<USER> $ ./cam_board
- “q” - quit
- “s” - save screen to PNG files to create slide show
- the names are chosen automatically 0001.png, 0002.png, …
- by default the files are saved in the current working directory
Adjust the configuration file
Edit aruco_cam_config to change settings.
You can make your own marker page with the markers from to_print/symbols. They should be placed in corners of a rectangle that matches the aspect ratio of your web cam. Careful: the orientation of the symbols is important and they might require rotation - see a4.svg for reference.
Conserve printer ink / toner
- tape one printout with the 4 markers to desk surface (make sure the circle is positioned correctly and use tape that can later be removed from the desk surface without damaging it)
- once the script recognizes the 4 ARUCO markers and stretches them to the whole screen place a blank sheet of paper over the taped printout
- if the camera moves, remove any paper covering the printout and the program will recalculate how to warp the camera image
Better resolution at the bottom
- laptop stands that allow tilting might help position the camera more perpendicular to the printout with markers resulting in better resolution at the bottom of the printable area
- manipulating the position of the laptop might damage it, be careful :-)
Python version error
In some linux distributions python 3 is the default. If that is not the case on your system you can:
adjust the first, hashbang, line of cam_board or …
… run through python 3:
<user> $ python3 ./cam_board
- ArUco markers made using this
- This is a simple script bodged togather from various opencv tutorials, here is a good place to start
- Sharpening kernel see wiki and this