Decapod Stereo Camera Calibration Workflows and Alternatives
Stereo Calibration
Stereo calibration requires:
1. 22 stereo images of the checkerboard
2. Outer corners should be visible in all images
Issues
1. Long process: 30s per stereo pair for capturing. 6 minutes for calibration script.
2. Unknown expectation: what is needed for calibration? What angles? What is the criteria for good images vs bad?
Approach 1: Move the Rig
Description:
Reposition tripod, adjust pitch and height to capture images.
Can have a systematic approach: 3 positions with 4 different height adjustments. At each high adjustment, adjust pitch 2 times = 24 frames (3 x 4 x 2)
Pros:
Pattern stays in one spot.
Cons:
User is required to move the rig around increasing likelihood of bumping cameras, or pulling cables out.
Rig may be heavy.
Tedious
Approach 2: Move the pattern with timer
Description:
User marks / mentally notes the boundaries of the camera views
initiates automatic calibration.
User moves and tilts randomly in front of cameras until 25 images are taken.
Optionally, the user can review the images and delete the bad ones and retake another sample.
Pros:
Automatic: User can just move the pattern around until done.
User doesn't have to move camera: reduces possible error.
Cons:
Higher change of user doesn't position pattern properly.
Timer may be too long, or too short depending on the user's ability.
User needs to hold pattern really still. Each camera captures one after the other (not simultaneous). Any movement of pattern between left-right shots will throw off calibration.
Approach 3: Move the pattern, prop up without timer
Description:
User marks / mentally notes the boundaries of the camera views
User positions the pattern in front, propping it up different ways for each shot.
Manually trigger cameras.
Optionally, the user can review the images and delete the bad ones and retake another sample.
Pros:
User doesn't have to hold pattern - little chance of pattern moving between camera exposures.
Cons:
Manual process: position, prop, capture - repeat 22 times.
User needs to think of different ways on how to prop pattern.