Focus Lens Aberration Correction for Zoom Tracking Precision
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Solution Overview
Problem
Conventional zoom tracking systems in video cameras fail to fully correct lens aberrations such as spherical aberration and barrel distortion at non-referenced object distances, leading to deteriorated tracking performance due to insufficient data storage and interpolation methods.
Innovation Solution
A focusing apparatus that includes an acquisition unit for cam locus data, a correction unit to adjust the focus lens position based on optical system aberrations, and a control unit to calculate and apply correction coefficients for precise focus control, using interpolation and aberration correction to maintain tracking performance across varying object distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If referenced cam locus curves are stored for multiple object distances, then zoom tracking performance is improved, but memory capacity requirements increase
Solution Approach 1:
The patent segments the cam locus data into two distinct components: (1) referenced cam locus curves stored in memory for multiple object distances, and (2) aberration correction data stored separately for each object distance. This segmentation allows the system to use compact stored data combined with calculated corrections, reducing overall memory requirements while maintaining tracking accuracy across all object distances.
Solution Approach 2:
The patent performs preliminary correction of aberration data for each object distance and stores these correction values in memory. During zoom tracking operation, the system retrieves the base cam locus curve and applies the pre-calculated aberration corrections, eliminating the need to store complete corrected cam locus curves for every object distance while maintaining high tracking performance.
2Quantity of substance
If interpolation processing is used to calculate cam locus curves at non-referenced object distances, then memory capacity is reduced, but tracking precision deteriorates due to uncorrected aberrations
Solution Approach 1:
The patent implements a feedback mechanism where aberration correction data is applied to the interpolated or calculated cam locus curves. The system retrieves base cam locus data, calculates the focus lens position through interpolation or calculation for non-referenced object distances, then applies aberration correction values specific to each object distance to refine the final focus position, ensuring high tracking precision is maintained.
Solution Approach 2:
The patent changes the parameter representation from storing complete cam locus curves for all object distances to storing base curves plus separate aberration correction parameters. This parameter transformation allows the system to maintain precision by applying object-distance-specific correction values to calculated positions, rather than relying solely on interpolation of uncorrected data.
3Reliability
If aberration correction is applied at each object distance, then tracking performance is improved, but device complexity increases
Solution Approach 1:
The patent performs aberration correction in advance during the data preparation phase, calculating and storing correction values for each object distance before runtime. During actual zoom tracking operation, the system simply retrieves pre-calculated correction values and applies them to the base cam locus data, significantly reducing real-time processing complexity while maintaining high tracking performance.
Solution Approach 2:
The patent creates simplified copies or representations of the aberration correction data in a compact format suitable for storage and rapid retrieval. Instead of performing complex optical calculations in real-time, the system uses pre-computed correction values that replicate the effect of full aberration correction, reducing processing complexity during zoom tracking while preserving accuracy.
Data Source
AI summary
A focusing apparatus includes an acquisition unit configured to acquire locus data that indicates a position of a focus lens that depends on an object distance and a position of a zoom lens, and an adjustment value used to adjust the position of the focus lens on the locus data, a correction unit configured to correct the adjustment value based on an aberration of an optical system that includes the zoom lens and the focus lens, and a control unit configured to control the position of the focus lens based on the locus data and the corrected adjustment value.