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.