Camera Calibration Using Rotatable Collimator and Segmented Apertures

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Solution Overview

Problem

Traditional camera calibration methods require a large amount of space to capture the entire field-of-view, making them inefficient in terms of space utilization.

Innovation Solution

A camera calibration system using a rotatable collimator with a target having a central aperture and peripheral apertures, where collimated light is provided to the camera, allowing for the determination of intrinsic parameters like distortion profile by rotating the collimator along an axis through the entrance pupil location, enabling precise alignment and measurement of spot positions to build a distortion profile.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional camera calibration methods are used to capture the entire field-of-view, then accurate intrinsic parameters can be determined, but a large amount of space (3-10 meters) is required

Engineering Contradiction:

Improveintrinsic parameters determinationVSAvoidcalibration space

Core Design Contradiction:

Measurement precisionVSArea of stationary object

Solution Approach 1:

The calibration target is segmented into multiple apertures (central aperture and multiple peripheral apertures) that can be selectively activated. By dividing the calibration process into multiple steps where different aperture combinations are used, the system achieves comprehensive calibration data collection within a compact space, eliminating the need for large calibration areas while maintaining measurement precision

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The calibration system employs dynamic aperture control where the central and peripheral apertures are selectively opened and closed during different calibration steps. This dynamic configuration allows the same physical space to serve multiple calibration purposes, enabling accurate intrinsic parameter determination without requiring large static calibration areas

Inventive Principle:

Principle #15Dynamics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This method reduces the space required for calibration while accurately determining intrinsic parameters such as focal length, principal point, and distortion profile, allowing for effective correction of distortions in captured images.

Implementation Method 1

positioning a camera to receive collimated light from a rotatable collimator

Methodology Applied

Scientific EffectCollimation:

Data Source

PatentEP3862806B1System and method for calibrating intrinsic parameters of a camera using optical raytracing techniques

Publication Date: 2023.05.03 APTIV TECHNOLOGIES LTD

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AI summary

A method of calibrating intrinsic parameters associated with a camera includes positioning a camera to receive collimated light from a rotatable collimator, wherein the collimated light is provided to the camera via a target having a central target aperture and a plurality of peripheral target apertures located on a periphery of the target. The method further includes rotating the collimator along a first axis extending through an entrance pupil location of the camera and recording spot positions associated with collimated light provided through one or more target apertures of the target at each first axis interval and determining a distortion profile associated with the camera based on the recorded spot positions measured at the plurality of first axis intervals.