Common Restoration Filter for MTF Azimuth Ratio Control
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Solution Overview
Problem
Existing image processing technologies face challenges in cost-effectively restoring image resolution degraded by aberrations in imaging optical systems, particularly due to the S/T difference in modulation transfer function (MTF) values between sagittal and tangential directions, which is difficult to address with common filters that amplify individual variations and do not adequately cope with manufacturing errors.
Innovation Solution
An image processing device and system that uses a common restoration filter corresponding to representative transfer functions of multiple imaging optical systems, with specific ratios of peak values and half-value widths in MTF curves between azimuth directions, to perform restoration processing while minimizing costs and preventing artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If individual restoration filters are created for each imaging optical system to minimize S/T difference, then image restoration quality is improved, but manufacturing costs increase significantly
Solution Approach 1:
The patent specifies precise parameter ranges for the MTF curves (peak value ratios ≥2, half-value width ratios ≥1.25, and specific azimuth direction relationships) that allow a common restoration filter to effectively handle S/T differences across multiple imaging optical systems, eliminating the need for individual filter creation while maintaining restoration quality
Solution Approach 2:
The invention creates a universal restoration filter that can be applied to multiple imaging optical systems by defining specific MTF curve characteristics that ensure the filter's effectiveness across different systems, making the filter multi-functional rather than system-specific
2Ease of manufacture
If common restoration filters are used for multiple imaging optical systems to reduce costs, then manufacturing costs are reduced, but individual variations in S/T difference are amplified
Solution Approach 1:
The patent defines specific parameter constraints for the MTF curves (peak value ratios ≥2, half-value width ratios ≥1.25, and azimuth direction relationships) that ensure the common restoration filter can handle individual variations without amplification, making the filter effective across different manufacturing tolerances
3Manufacturing precision
If the number of lenses and outer diameter dimension are increased to suppress S/T difference due to design, then S/T difference is reduced, but device complexity and cost increase
Solution Approach 1:
The patent replaces the mechanical/optical approach of increasing lens count and dimensions with an image processing approach using restoration filters, substituting physical system complexity with computational processing to achieve S/T difference suppression
Data Source
AI summary
Provided are an image processing device, an image processing system, an image processing method, and an imaging optical system group capable of suppressing an increase in costs and appropriately restoring an image. In the imaging optical system, in a case where a first MTF curve M1 indicating an MTF value in a first azimuth direction with respect to an amount of defocus from a focal position is compared with a second MTF curve M2 indicating an MTF value in a second azimuth direction with respect to the amount of defocus from the focal position, a ratio of a peak value P1 of the first MTF curve M1 to a peak value P2 of the second MTF curve M2 is equal to or greater than 2, and a ratio of a half-value width HW2 of the second MTF curve M2 to a half-value width HW1 of the first MTF curve M1 is equal to or greater than 1.25. The restoration filter is a common filter corresponding to a representative value of transfer functions in a plurality of same type imaging optical systems.