Adaptive Focus Control for Changing Subject Direction
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Solution Overview
Problem
Existing image pickup apparatuses face challenges in maintaining focus on moving subjects when their direction changes over time, leading to potential mistakes in predictive positioning and careless focus adjustments.
Innovation Solution
An image pickup apparatus equipped with a processor and circuit configuration that includes an image pickup unit, subject detecting unit, focus detection unit, and control unit, which predicts the subject's position after a predetermined time and adjusts focus control conditions based on time-series changes in detection results, ensuring accurate focus maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the moving position of the subject is predicted according to the orientation of the subject and the moving speed corresponding to the age and/or type of the subject, then the focus control can be performed proactively, but when the moving direction of the subject changes in time series, mistakes in predictive position occur and focus control becomes inaccurate
Solution Approach 1:
The patent applies dynamics by making the prediction condition adaptable to changing subject behavior. The control unit dynamically switches between different prediction conditions based on whether the subject's moving direction is constant or changing. This allows the system to optimize predictive accuracy for each specific scenario, resolving the contradiction between proactive focus control and accuracy when direction changes.
Solution Approach 2:
The patent changes the prediction condition parameter based on the subject's movement pattern. When the moving direction is determined to be changing, the system switches to a second prediction condition that accounts for direction changes, rather than continuously applying the first prediction condition. This parameter change resolves the accuracy issue when subjects change direction.
2Device complexity
If a fixed prediction condition is used for focus control, then the control logic is simple, but it cannot adapt to subjects that change their moving direction, leading to focus errors
Solution Approach 1:
The patent implements feedback by having the control unit continuously monitor the subject's detection results over time and determine whether the moving direction is changing. Based on this feedback, the system automatically switches between different prediction conditions. This feedback mechanism maintains reliability without requiring overly complex fixed logic, as the system adapts based on observed subject behavior.
Solution Approach 2:
The control logic transitions from a static fixed condition to a dynamic adaptive system. The control unit evaluates subject movement patterns in real-time and adjusts the prediction condition accordingly. This dynamic approach maintains simplicity while improving reliability, as the complexity is introduced only when needed (when direction changes are detected).
Data Source
AI summary
An image pickup apparatus capable of keeping a focus on a subject even when a moving direction of the subject changes in time series is provided. The image pickup apparatus comprising at least one processor and/or circuit configured to function as following units, an image pickup unit configured to pick up a subject image formed by an image pickup optical system and generate image data, a subject detecting unit configured to detect a subject included in the image data generated by the image pickup unit and obtain a subject detection result, a focus detection unit configured to obtain a focus detection result of a focus detection area, which is set based on the subject detection result, and a control unit configured to perform a predictive calculation, which predicts a position of the subject detected by the subject detecting unit at a time after a predetermined period of time has elapsed from a focus detection time, and perform focus control of the image pickup optical system. The control unit changes at least one of a subject position prediction condition and a focus control condition according to time-series changes in the subject detection result obtained by the subject detecting unit and the focus detection result obtained by the focus detection unit.