Lens Apparatus Light Amount Compensation via Polynomial Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing camera systems face challenges in compensating for peripheral light amount drops during zooming, focusing, and iris diameter changes due to limited data capacity and interpolation errors, leading to overcompensation or undercompensation issues.
Innovation Solution
A lens apparatus with an optical correction system that includes a focus lens unit, zoom lens unit, iris, and detectors to determine image pickup conditions, using an optical correction table with n-th order polynomial expressions for light amount correction, and interpolation processing to calculate and apply correction amounts for accurate light amount compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the effective diameter of the lens is increased to cover all light flux paths during operation, then the peripheral light amount is improved, but the size and weight of the lens apparatus increases and aberration correction becomes more difficult
Solution Approach 1:
The patent replaces the mechanical/optical solution of increasing lens effective diameter with an image processing approach. The camera apparatus performs computational correction of peripheral light amount drops through software algorithms, eliminating the need for larger physical lens elements and their associated weight and complexity.
Solution Approach 2:
The patent changes the approach from physical parameter modification (lens diameter) to digital parameter adjustment (image processing coefficients). By using gamma correction and peripheral light amount correction coefficients, the system achieves the desired illumination uniformity through parameter transformation rather than physical expansion.
2Measurement precision
If discrete compensation data is held for multiple zoom states, then the peripheral light amount compensation accuracy is improved, but the data capacity requirement increases
Solution Approach 1:
The patent segments the correction data into two distinct components: gamma correction data and peripheral light amount correction data. This segmentation allows each type of correction to be handled independently with optimized data structures, reducing the total data capacity required while maintaining comprehensive correction accuracy across all zoom states.
Solution Approach 2:
The patent implements dynamic selection of correction data based on the current zoom state. The system automatically switches between pre-calculated correction sets corresponding to different zoom positions, providing accurate compensation without storing excessive data for all possible intermediate states. This dynamic approach balances precision with data efficiency.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Provided is a lens apparatus attachable and detachable to a camera apparatus including: a memory storing information for light amount compensation for image data obtained by pickup of an image formed by the lens apparatus; and a communication device configured to transmit the information to an external apparatus, the information including a coefficient of a polynomial having an n-th order with respect to an image height, "n" being a non-negative integer, the coefficient corresponding to one of a plurality of focal lengths, the plurality of focal lengths including a focal length "f', which satisfies a conditional expression: 0.9<f/ft/(Fnw/Fnt)<4, where Fnw represents an effective f-number at a wide angle end, Fnt represents an effective f-number at a telephoto end, and "ft" represents a focal length at the telephoto end.