Autofocus Lens Position Control for Mixed Depth Subjects
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing autofocus methods based on phase difference detection struggle to focus on subjects that are both close and far from the image capturing device simultaneously, as they cannot achieve focus for both subjects in the same region.
Innovation Solution
A control device and method that calculates the focus position of multiple phase difference detection regions and determines the lens position based on an average value or specific conditions, such as a predetermined range or histogram analysis, to effectively focus on either the macro or infinity side, even when both near and far subjects are present.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If phase difference detection method is used for autofocus, then focusing speed is improved, but inability to focus on both close and far subjects simultaneously occurs
Solution Approach 1:
The imaging element is divided into multiple phase difference detection regions (first region and second region) that can independently detect phase differences for subjects at different depths. This segmentation allows the system to simultaneously process focus information for both close and far subjects, resolving the contradiction between fast autofocus and multi-depth adaptability.
Solution Approach 2:
Different regions of the imaging element are assigned different functional qualities - the first phase difference detection region is optimized for detecting close subjects while the second region is optimized for far subjects. This local differentiation enables each region to excel at specific depth ranges, allowing simultaneous focus on multiple subjects at different distances.
2Device complexity
If average value of all focus positions is used, then calculation simplicity is improved, but accuracy in mixed subject scenarios deteriorates
Solution Approach 1:
Instead of calculating the average of all phase difference detection regions, the system segments the calculation by separately determining focus positions from the first and second regions, then selectively combining them based on subject detection results. This segmented approach maintains calculation simplicity while improving accuracy for mixed subject scenarios.
Solution Approach 2:
The lens position determination becomes dynamic - the system adaptively selects which region's focus position to use (first region for close subjects, second region for far subjects) based on real-time subject detection. This dynamic selection mechanism maintains computational efficiency while achieving high accuracy in varying subject conditions.
Data Source
AI summary
Provided is a control device that includes a calculation unit that calculates, on a basis of a result of capturing a subject image passed through a focus lens by using an imaging element including a plurality of phase difference detection regions, a focus position of each of the phase difference detection regions and a determination unit that determines a position of the focus lens on a basis of an average value of the focus positions of the phase difference detection regions calculated by the calculation unit and falling within a predetermined range from the focus position on an infinity side or macro side.