fθ Lens Distortion Correction in Projection Imaging
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Solution Overview
Problem
The accuracy of image projection correction in projector-camera systems using fθ lenses is lower than that of f tan θ lenses due to significant lens distortion, making existing calibration methods inadequate for maintaining geometric accuracy, especially in dome-type curved surfaces.
Innovation Solution
An information processing apparatus and method that estimates the posture of projection and imaging sections using an image projection model incorporating the distortion factor of fθ lenses, allowing for accurate calibration of internal and external parameters to correct lens distortion and enhance geometric accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If calibration is performed without regard to lens distortion (as in f tan θ lens systems), then the device complexity is reduced and ease of operation is improved, but the measurement precision of projection correction deteriorates significantly
Solution Approach 1:
The patent changes the calibration parameters by explicitly incorporating lens distortion factors (k1, k2, p1, p2) into the calibration model for fθ lenses. This allows the system to account for the significant distortion characteristics of fθ lenses while maintaining an automated calibration process, thus resolving the contradiction between ease of operation and measurement precision.
2Measurement precision
If an image projection model incorporating distortion factor is used, then the measurement precision of projection correction is improved, but the device complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-defining the distortion model parameters (k1, k2, p1, p2) and integrating them into the calibration workflow before actual calibration occurs. This preparation allows the complex distortion correction to be handled systematically through automated parameter optimization, reducing the perceived complexity during operation while maintaining high measurement precision.
3Area of stationary object
If fθ lens is used to achieve wider field of view, then the area of projection is improved, but the manufacturing precision of projection correction deteriorates due to lens distortion
Solution Approach 1:
The patent addresses this contradiction by changing the approach to parameter modeling - specifically by incorporating distortion parameters (k1, k2, p1, p2) into the projection model. This allows the system to maintain geometric accuracy across the wide projection area enabled by fθ lenses, as the distortion effects are compensated through the calibrated parameters rather than limiting the projection area.
Data Source
AI summary
The present disclosure relates to an information processing apparatus and an information processing method for suppressing a decrease in the accuracy of image projection correction. By use of an image projection model using a distortion factor of an fθ lens with an image height of incident light expressed by the product of a focal point distance f and an incident angle θ of the incident light, the posture of a projection section for projecting an image and the posture of an imaging section for capturing a projection plane to which the image is projected are estimated. The present disclosure may be applied, for example, to information processing apparatuses, projection apparatuses, imaging apparatuses, projection imaging apparatuses, projection imaging control apparatuses, or image projection and imaging systems.