Dynamic Focus Detection Area Selection for Moving Objects
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Solution Overview
Problem
In imaging apparatus autofocus systems, it is challenging to maintain focus on moving objects without causing perspective conflicts or missing the object, especially when the autofocus area needs to be adjusted dynamically to accommodate object movement.
Innovation Solution
A focus detection apparatus that selects between a first and second focus detection area based on whether the object can be continuously captured within the first area, with the second area being wider to include the periphery of the first, ensuring stable focus detection and preventing perspective conflicts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the AF area is made wider to track moving objects, then the object can be continuously captured, but perspective conflict occurs or focus accuracy decreases
Solution Approach 1:
The patent dynamically switches between a first AF area (smaller, higher precision) and a second AF area (larger, better for tracking) based on whether the object can be continuously captured. This dynamic adjustment resolves the contradiction by adapting the AF area size to the specific tracking situation, ensuring both continuous capture and focus accuracy are maintained optimally.
2Measurement precision
If the AF area is made smaller to improve focus accuracy, then focus precision increases, but the object may be lost when moving
Solution Approach 1:
The system dynamically adjusts the AF area size based on capture success. When the object cannot be continuously captured in the first AF area, it switches to the larger second AF area to ensure continuous tracking, thereby resolving the contradiction between focus accuracy and reliable object capture.
3Measurement precision
If prediction of future focus position is used, then focus on moving object improves, but AF area specification becomes uncertain when prediction fails
Solution Approach 1:
The patent prepares two AF area options (first and second) in advance to handle prediction failures. When prediction fails or the object cannot be continuously captured, the system has a pre-prepared larger second AF area to fall back on, ensuring continuous tracking without uncertainty about AF area specification.
Data Source
AI summary
A focus detection apparatus includes a selection unit configured to select as the focus detection area a first focus detection area and a second focus detection area including the first focus detection area and its periphery, and an information acquiring unit configured to acquire first information on whether or not the object moving within the imaging screen can be continuously captured in the first focus detection area. The selection unit selects the first focus detection area when the first information indicates that the object can be continuously captured in the first focus detection area, and the selection unit selects the second focus detection area when the first information indicates that the object cannot be continuously captured.