Camera Calibration System Using Segmented Pattern Positioning
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Solution Overview
Problem
Existing camera calibration methods fail to accurately estimate intrinsic parameters, such as focal length and lens distortion, due to insufficient discriminatory information from calibration patterns when they are too close or too far from the camera, leading to sparse feature distribution or distortion.
Innovation Solution
A calibration system and method that capture images of a calibration pattern at different positions and orientations across the camera's field of view, using algorithms to detect and adjust the pattern's placement to ensure optimal coverage and minimize distortions, thereby improving the estimation of intrinsic parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the calibration pattern is placed close to the camera to encompass the complete field of view, then the coverage area is improved, but the discriminatory information becomes insufficient due to sparse feature distribution
Solution Approach 1:
The calibration process is segmented into multiple steps: first capturing an initial image to determine the field of view, then dividing the calibration pattern into multiple sections that are positioned at different locations within the field of view. This segmentation allows each section to provide sufficient discriminatory information while collectively covering the entire field of view.
Solution Approach 2:
The calibration approach transitions from a single-plane calibration pattern to a multi-dimensional arrangement by positioning calibration pattern sections at different locations and orientations within the field of view. This dimensional expansion ensures both comprehensive coverage and sufficient feature density for accurate parameter estimation.
2Measurement precision
If the calibration pattern is placed far from the camera to provide sufficient discriminatory information, then the feature distribution is improved, but the coverage area decreases
Solution Approach 1:
Instead of using a single large calibration pattern, the system segments the calibration into multiple smaller sections captured at different positions. Each section provides sufficient discriminatory information with proper feature density, while the collection of sections collectively covers the entire field of view.
Solution Approach 2:
The calibration process captures images of calibration pattern sections that may extend beyond the strict boundaries of the field of view in some directions, ensuring sufficient discriminatory information is obtained. This partial excess in coverage in certain areas compensates for reduced coverage in other areas, maintaining overall accuracy.
3Measurement precision
If multiple images are captured at different positions and orientations to improve calibration accuracy, then the intrinsic parameter estimation is improved, but the calibration time increases
Solution Approach 1:
The system performs preliminary capture of the field of view using the camera before beginning the calibration pattern positioning. This preliminary action allows the system to plan the calibration pattern sections' positions and orientations in advance, optimizing the number and placement of sections to minimize the total number of images required for accurate calibration.
Solution Approach 2:
The calibration process dynamically adjusts the positioning and orientation of calibration pattern sections based on the captured field of view characteristics. This dynamic adaptation allows the system to optimize the calibration sequence, capturing only the necessary number of images with appropriate sections to achieve accurate intrinsic parameter estimation without unnecessary time consumption.
Data Source
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AI summary
A calibration system comprises input means operable to receive a set of images, each having a calibration pattern occupying a region of a captured scene, an image processor operable to calculate a combined image region corresponding to the combined regions of calibration patterns captured within the set of images, and an output processor operable to generate an output indicative of a desired region of a scene within which to capture the calibration pattern within a subsequent image.