Minimal Set of Parameters Based Depth-Dependent Distortion Model and Its Flexible Calibration Method for Improving Accuracy of Stereo Vision Systems

Core Concepts

A minimal set of parameters based depth-dependent distortion model (MDM) is proposed to improve the accuracy and simplify the calibration process of stereo vision systems. The MDM considers both radial and decentering lens distortions, and an easy and flexible calibration method is presented that does not require the camera to be perpendicular to the calibration pattern.

Abstract

This paper proposes a minimal set of parameters based depth-dependent distortion model (MDM) to improve the accuracy and simplify the calibration process of stereo vision systems. The key highlights are:

The MDM considers both radial and decentering lens distortions, with a total of 8 unknown parameters, making it more simplified compared to previous depth-dependent models.

An easy and flexible calibration method is presented for the MDM, which does not require the camera to be perpendicular to the calibration pattern. The cameras only need to observe the planar pattern at different orientations.

Experimental validation shows the MDM improves the calibration accuracy by 56.55% and 74.15% compared to the Li's distortion model and traditional Brown's distortion model, respectively.

An iteration-based 3D reconstruction method is proposed to iteratively estimate the depth information in the MDM during reconstruction, improving the accuracy by 9.08% compared to the non-iteration method.

The proposed MDM and its calibration method provide a more efficient and accurate solution for stereo vision systems, especially in close-range applications where depth-dependent distortion is significant.

Stats

The MDM improved the calibration accuracy by 56.55% and 74.15% compared with the Li's distortion model and traditional Brown's distortion model, respectively.
The iteration-based 3D reconstruction method improved the accuracy by 9.08% compared to the non-iteration method.

Quotes

"Depth position highly affects lens distortion, especially in close-range photography, which limits the measurement accuracy of existing stereo vision systems."
"Compared with some general calibration methods for the depth-dependent distortion models, such as the model proposed by Li and Sun, the proposed technique does not need the camera to be adjusted to be perpendicular to the planar pattern during the calibration, which is easy to use and flexible."

Key Insights Distilled From

A Minimal Set of Parameters Based Depth-Dependent Distortion Model and Its Calibration Method for Stereo Vision Systems

by Xin Ma,Puche... at arxiv.org 05-01-2024

https://arxiv.org/pdf/2404.19242.pdf

Deeper Inquiries

How can the proposed MDM and calibration method be extended to handle more complex lens distortion models, such as those involving higher-order terms or non-polynomial functions

The proposed MDM and calibration method can be extended to handle more complex lens distortion models by incorporating higher-order terms or non-polynomial functions into the distortion model. For higher-order terms, additional parameters can be introduced to capture the increased complexity of the distortion. This would involve expanding the distortion model to include terms beyond the traditional radial and decentering distortions, such as tangential distortion or higher-order radial distortions.
In the case of non-polynomial functions, the distortion model can be adapted to accommodate these functions by using a more flexible parameterization scheme. This could involve fitting the distortion model to the specific characteristics of the lens distortion using techniques like spline interpolation or neural networks. By incorporating these advanced modeling techniques, the MDM can be tailored to handle a wider range of distortion patterns and improve the accuracy of stereo vision systems in capturing complex lens distortions.

What are the potential limitations of the MDM and its calibration method, and how could they be addressed in future work

Potential limitations of the MDM and its calibration method may include:

Limited Generalizability: The MDM may be optimized for specific lens types or distortion patterns, limiting its applicability to a broader range of stereo vision systems.
Complexity of Calibration: The calibration process for the MDM, although simplified compared to traditional methods, may still require manual adjustments and careful setup, leading to potential errors and inefficiencies.
Initial Value Sensitivity: The MDM may be sensitive to the initial values of the distortion parameters, making it challenging to find accurate optimized values without a robust initialization strategy.

To address these limitations in future work, several approaches can be considered:

Model Flexibility: Enhance the flexibility of the MDM to adapt to different lens characteristics by incorporating adaptive parameterization schemes or data-driven approaches.
Automation: Develop automated calibration techniques that reduce the manual intervention required during the calibration process, improving efficiency and accuracy.
Robust Initialization: Implement robust initialization methods to ensure accurate estimation of the distortion parameters, reducing sensitivity to initial values and enhancing calibration reliability.

By addressing these limitations, the MDM and its calibration method can be further optimized for real-world applications and provide more robust and accurate results in stereo vision systems.

Given the improvements in accuracy, how could the proposed techniques be leveraged to enable new applications or enhance the performance of existing stereo vision systems in real-world scenarios

The improvements in accuracy achieved by the proposed techniques can enable new applications and enhance the performance of existing stereo vision systems in various real-world scenarios. Some potential applications and enhancements include:

Industrial Automation: The enhanced accuracy of the MDM and calibration method can benefit industrial automation processes, such as robotic vision systems, quality control in manufacturing, and object tracking in logistics.
Autonomous Vehicles: The improved calibration accuracy can enhance the depth perception and object recognition capabilities of stereo vision systems in autonomous vehicles, leading to safer and more reliable navigation.
Medical Imaging: In medical imaging applications, the increased accuracy of 3D reconstruction can improve surgical planning, patient monitoring, and diagnostic imaging using stereo vision systems.
Augmented Reality: The precise calibration of stereo vision systems can enhance the realism and accuracy of augmented reality applications, enabling more immersive and interactive user experiences.

By leveraging the advancements in accuracy and calibration efficiency offered by the proposed techniques, stereo vision systems can be deployed in a wide range of applications, leading to enhanced performance and expanded capabilities in real-world scenarios.