Data Collection for Vehicle-Camera Calibration

Calibration Target

Checkerboard of more than two horizontal inner corners and vertical inner corners. You can use the attached pdf. It has seven internal corners horizontally and nine internal corners vertically. https://drive.google.com/file/d/1mTR8HTpvROE1Pv0rmXEBVLSxs_yMDnvf/view?usp=sharing

Prerequisites

Reference Points for Data Collection

Paste the adhesive tape on the ground along the vehicle's edges based on the camera-facing direction. Assume calibrating the front-facing camera sensor as an example for this collection process. Paste the adhesive tape shown in the image below for the front-facing camera. (See How to paste adhesive tape along the vehicle for different camera-facing directions?)

To maintain a fixed distance between the target and the vehicle, paste the adhesive tape parallel to the vehicle with a 1-10m distance between the target and the vehicle, as shown in the below image. It acts as a Reference Line (RL) for the target.

Definitions

Vehicle Reference Point (VRP)

The adhesive tape's left intersection point (from the camera perspective) along the vehicle's edges, as shown in the below image.

Intersection Reference Point (IRP)

This is the left intersection point of the adhesive tape from the vehicle with the adhesive tape from the reference line, as shown in the below image.

Target Reference Point (TRP)

This is the bottom-left edge corner of the target, as shown in the below image.

Vehicle dimensions

Left wheelbase

Distance between the center of the front left wheel to the center of the rear left wheel.

Right wheelbase

Distance between the center of the front right wheel to the center of the rear right wheel.

Note: For a rectangular vehicle, Left wheelbase = Right wheelbase

Front track

Distance between the outer edge of the front left wheel to the outer edge of the front right wheel.

Rear track

Distance between the outer edge of the rear left wheel to the outer edge of the rear right wheel.

Note: For a rectangular vehicle, Front track = Rear track

Front overhang

Distance between the center of the front left/right wheel to the vehicle's front.

Rear overhang

Distance between the center of the rear left/right wheel to the vehicle's rear.

Data collection

  1. Mount the camera onto the vehicle and note the distance between VRP and IRP.

  2. Place the board at the Reference Line and ensure the board is parallel or perpendicular to the car.

  3. Take an image from the mounted camera and note the distance between IRP and TRP.

  4. Move the board along the Reference Line, and at every placement, take an image from the mounted camera and note the distance between IRP and TRP.

Note: We recommend capturing at least three images with the target perpendicular to the ground and at least three images parallel to the ground in different positions on the Reference Line to maximize accuracy.

How to paste adhesive tape along the vehicle for different camera-facing directions?

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