Zoom Lens Distortion Correction via Range-Specific Processing
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Solution Overview
Problem
Existing image-pickup apparatuses face challenges in accurately correcting optical distortions across the entire zoom range, leading to image quality deterioration and increased calculation and memory loads, especially in real-time applications like monitoring cameras.
Innovation Solution
The apparatus employs a correcting part that differentiates between two zoom ranges, performing more extensive distortion correction in areas with higher distortion and limiting processing in areas with lower distortion, using polynomial approximation and memory-efficient data storage to maintain image quality while reducing computational load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If accurate distortion correction is performed over the entire zoom range, then distortion correction accuracy is improved, but image quality deteriorates due to resolution loss from coordinate transformation
Solution Approach 1:
The patent applies different correction strategies to different zoom ranges: in the wide-angle zoom range where distortion exceeds a threshold, coordinate transformation correction is applied; in the telephoto zoom range where distortion is below the threshold, correction is omitted or reduced. This local differentiation prevents unnecessary resolution loss while maintaining correction accuracy where needed.
Solution Approach 2:
The patent changes the correction parameter (correction amount) based on the zoom range. By adjusting the correction strength according to the distortion amount at each zoom position, the system achieves effective correction where distortion is significant while avoiding over-correction that would degrade image quality in ranges where distortion is minimal.
2Measurement precision
If accurate distortion correction is performed over the entire zoom range, then distortion correction accuracy is improved, but calculation load increases
Solution Approach 1:
The patent extracts and applies correction only in the specific zoom range where distortion exceeds the predetermined threshold. By removing the correction operation from zoom ranges where it is unnecessary, the system significantly reduces the calculation load while maintaining correction accuracy where it matters.
Solution Approach 2:
Instead of applying full correction across the entire zoom range, the patent applies partial correction only where needed (wide-angle range with high distortion). This partial action approach reduces computational effort while achieving sufficient correction performance for the application.
3Measurement precision
If accurate distortion correction is performed over the entire zoom range, then distortion correction accuracy is improved, but memory capacity requirements increase
Solution Approach 1:
The patent extracts and stores distortion correction data only for the zoom range where distortion exceeds the threshold. By eliminating storage requirements for correction data in the telephoto range where correction is not applied, the system reduces memory capacity requirements while maintaining correction accuracy where needed.
4Measurement precision
If extensive distortion correction processing is applied, then distortion correction accuracy is improved, but image resolution decreases due to coordinate transformation
Solution Approach 1:
The patent applies coordinate transformation correction only in the wide-angle zoom range where distortion is significant, rather than uniformly across all zoom ranges. This localized approach preserves image resolution in the telephoto range where correction would be unnecessary and resolution-degrading.
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 approach allows for favorable image quality across all zoom ranges without excessive distortion correction, reducing calculation load and memory requirements, thereby enhancing performance and image resolution.
Implementation Method 1
an image-pickup element that photoelectrically converts an optical image formed by an image-pickup optical system
Data Source
AI summary
An image-pickup apparatus includes an image-pickup element that photoelectrically converts an optical image formed by an image-pickup optical system having a zoom function, and a correcting part that performs correction processing for a distortion component in image data generated based on an output from the image-pickup element, the distortion component corresponding to a distortion of the image-pickup optical system. The image-pickup optical system provides a first zoom range in which a distortion amount at a certain image height is larger than a predetermined value and a second zoom range in which a distortion amount at the certain image height is smaller than the predetermined value. The correcting part performs the correction processing so that the distortion component remains in a first corrected image data in the first zoom range is larger than the distortion component remaining in a second corrected image data in the second zoom range.