Camera Calibration Using Perspective-Deformed Planar Patterns
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Solution Overview
Problem
Existing camera calibration methods struggle with accurate feature point detection and parameter estimation due to variations in viewing angles and distances, leading to suboptimal calibration results.
Innovation Solution
A method involving first and second camera calibrations, where a deformed pattern is output to appear as if viewed from the camera's perspective, using feature point positions on both images and world coordinates to improve detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single camera calibration is performed using a planar pattern, then the calibration process is simple and quick, but the accuracy of feature point detection and parameter estimation deteriorates due to variations in viewing angles and distances
Solution Approach 1:
The calibration process is segmented into two distinct stages: first calibration using a planar pattern, and second calibration using a deformed pattern. This segmentation allows each stage to serve a specific purpose - the first calibration provides a quick initial estimate, while the second calibration refines the accuracy by compensating for viewing angle and distance variations through pattern deformation.
Solution Approach 2:
The first calibration using the planar pattern serves as a preliminary action that provides initial camera parameters. These initial parameters are then used to generate the deformed pattern for the second calibration, which further refines the accuracy. This preliminary action enables the system to start with a simple calibration and progressively improve accuracy.
2Device complexity
If a single camera calibration is performed using a planar pattern, then the calibration process is simple, but the accuracy of parameter estimation deteriorates due to variations in viewing angles and distances
Solution Approach 1:
The calibration process is divided into two segments: a simple first calibration using a planar pattern that maintains low complexity, and a second calibration using a deformed pattern that improves accuracy. The segmentation allows the system to maintain simplicity where possible while introducing additional complexity only when needed for accuracy improvement.
Solution Approach 2:
The pattern undergoes parameter changes from a standard planar configuration to a deformed configuration between the first and second calibrations. This parameter change in the pattern geometry enables the second calibration to compensate for viewing angle and distance variations, thereby improving parameter estimation accuracy without requiring complete process redesign.
3Measurement precision
If the planar pattern is deformed to appear as if viewed from camera perspective, then feature point detection accuracy improves, but the overall system complexity increases due to additional calibration steps
Solution Approach 1:
The system implements feedback by using the results of the first calibration to inform the second calibration process. The initial camera parameters obtained from the first calibration are used to generate the deformed pattern, and the second calibration feedback refines these parameters. This feedback mechanism improves accuracy while managing complexity through iterative refinement rather than complete redesign.
Solution Approach 2:
The first calibration serves as a preliminary action that prepares the system for the second calibration. By obtaining initial parameters first, the system can then proceed to the more accurate second calibration with a solid foundation, reducing the complexity burden on any single calibration step while achieving high overall accuracy.
Data Source
AI summary
An information processing apparatus includes a calibration calculation unit that performs first calibration of a camera based on a first feature point position of a planar pattern included in a first image captured by the camera and a second feature point position of the planar pattern on world coordinates, and an output unit that outputs, based on the first calibration, a deformed pattern obtained by deforming the planar pattern in such a way that the deformed pattern appears on a second image captured by the camera as if the camera were facing the planar pattern.The calibration calculation unit acquires the second image of the deformed pattern captured by the camera, and performs second calibration of the camera based on a third feature point position of the deformed pattern in the second image and a fourth feature point position of the deformed pattern on the world coordinates.