Auto Focus Lens Position Correction via Frequency Band Conversion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing auto focus (AF) systems in cameras face challenges in accurately adjusting the focus lens due to differences between the frequency bands used for determining the AF location and the image surface location of the imaging lens, leading to errors that affect image quality.
Innovation Solution
An AF adjusting apparatus and camera system that includes an imaging sensor, AF estimation value calculating unit, focus lens driver, location detector, optimum location calculating unit, and storage unit to calculate and correct the focus lens position using optimum location error information, ensuring accurate focus adjustment by comparing and correcting the difference between the AF detection frequency band and the image surface frequency band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the AF detection uses a first frequency band to determine focus lens position, then the autofocus operation can be performed, but a location error occurs due to difference from the second frequency band used for determining the image surface location
Solution Approach 1:
The patent applies parameter changes by introducing frequency band conversion. The AF detection unit detects focus lens position using a first frequency band, then a frequency converter converts this position to an equivalent position in a second frequency band that matches the image surface location determination, thereby resolving the position discrepancy caused by frequency band differences
Solution Approach 2:
The patent uses an intermediary approach by introducing a frequency converter as a mediating component. This converter acts as an intermediary that translates the focus lens position detected in the first frequency band into the corresponding position in the second frequency band, enabling accurate alignment between AF detection and image surface location
2Device complexity
If the focus lens position is determined without frequency band correction, then the system complexity is reduced, but image quality deteriorates due to focus accuracy errors
Solution Approach 1:
The patent applies parameter changes by transforming the focus lens position parameter from one frequency band domain to another. The frequency converter changes the parameter representation to account for the frequency band difference, ensuring that the position information remains accurate across different frequency domains without requiring complex hardware modifications
Solution Approach 2:
The patent substitutes a mechanical correction approach with a signal processing approach. Instead of using complex mechanical adjustment mechanisms to correct focus position, the system uses frequency band conversion through signal processing to achieve the same correction effect, thereby reducing mechanical complexity while maintaining precision
Data Source
AI summary
An auto focus (AF) adjusting apparatus and a camera system of a lens replaceable camera are disclosed. AF is performed by correcting a location error of a focus lens due to a difference between a frequency band for performing AF detection and a frequency band for determining an improved location of an image surface of an imaging lens, and/or a target region for detecting a focal point.