Introduction: How to Make a Camera Calibration Pattern
Most computer vision problems rely on having a well calibrated camera, to know the focal length, center of the image and possibly undistort your image.
You can calibrate your camera using software, for instance by following this ROS tutorial.
To get good results a larger pattern is recommended, here is how to make one for $1.50
Step 1: Print a Poster
Printing a large poster can be a bit expensive, and will require finding a print shop.
Instead I decided to use the online printing from UPS which is cheap and wildly available
I used PosteRazor to split a large check pattern to fit onto the largest sheets of paper that UPS offers (ledger 11x17 inches)
You can download the file for the patterns ready to print on 11x17 paper or legal paper 8.5x14.
If you have access to different kinds of paper, I recommend using PosteRazor to split the original file (use 0 for overlapping size).
Step 2: Assemble
For this step you'll need glue and optionally painter's tape.
I cut the extra margin on one of the two pieces of paper and used the remaining margin to glue the two together
I held the two pieces of paper together with painter tape before gluing them, as the check pattern needs to be relatively precise
Finally I touched up the black junctions with a sharpie.
You're now ready to run the calibration software
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