Imaging Apparatus Focus Tracking for Turnabout Subjects
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Solution Overview
Problem
Conventional imaging systems face challenges in accurately tracking fast-moving subjects during continuous imaging, especially when the subject's direction changes rapidly, leading to potential focus issues due to inadequate lens driving mechanisms.
Innovation Solution
An imaging apparatus equipped with a focus detection unit, position detection unit, estimation unit, and turnabout determination unit that prioritizes more recent data when tracking subjects that change direction, adjusting the number of data pairs used for estimation based on the subject's speed and movement patterns to enhance tracking accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the imaging lens is driven between frames based on past focus detection results, then tracking is performed for moving subjects, but the imaging lens may go past the appropriate focus position for fast-moving subjects whose direction reverses or changes instantly
Solution Approach 1:
The system performs preliminary focus detection and estimation before the actual imaging operation. By detecting focus information in advance and estimating the image plane position trajectory, the imaging lens can be positioned more accurately before capture, preventing it from going past the appropriate focus position even for fast-moving subjects that change direction
Solution Approach 2:
The system uses focus detection results from multiple time points as feedback to continuously update and refine the estimation of the image plane position. This feedback mechanism allows the system to adapt to direction changes of fast-moving subjects and maintain accurate focus tracking
2Speed
If the imaging lens is driven only in a short period from completion of focus detection to imaging operation, then the system responds quickly, but it becomes difficult for the imaging lens to accurately track fast-moving subjects
Solution Approach 1:
The system performs focus detection and image plane position estimation in advance, before the actual imaging operation begins. This preliminary action extends the tracking preparation time without delaying the imaging capture, allowing the imaging lens to accurately track fast-moving subjects while maintaining quick response
Solution Approach 2:
The system continuously performs focus detection and updates the image plane position estimation throughout the period from focus detection completion to imaging operation. This continuous useful action ensures the imaging lens maintains accurate tracking of fast-moving subjects throughout the entire interval
Data Source
AI summary
An imaging apparatus that performs continuous imaging, includes: a focus detection unit that perform focus detection and calculates an amount of defocus in each of a plurality of imaging operations; a position detection unit that detects an image plane position corresponding to a subject position using the amount of defocus; an estimation unit that estimates a next image plane position using a plurality of pairs of data regarding the image plane position and a time at which the amount of defocus has been detected; and a turnabout determination unit that determines whether a subject is a turnabout subject, which is a subject that moves towards the imaging apparatus, changes direction of movement, and then moves away from the imaging apparatus. The number of pairs of data used for the estimation decreases based on a ratio of a highest image plane speed in past scenes to a current image plane speed.