Camera Auto-Focus Control for Panning Stability
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Solution Overview
Problem
Existing auto-focus systems in image pickup apparatuses face challenges in maintaining focus during panning or tilting operations, leading to unsuccessful focusing due to the evaluation value dropping or varying significantly, causing the lens to remain out of focus on subjects, especially in professional cameras with large lenses used in severe environments.
Innovation Solution
A control apparatus that calculates relative angle variations and detects mode changes to determine when to start the focus position control process, using a focus position control process startup unit to manage the focus position through a driver, thereby reducing the time required for auto-focus and minimizing unnecessary focusing operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the image pickup apparatus continuously performs auto-focus evaluation during panning or tilting operations, then the focus position can be adjusted in response to evaluation value changes, but the subject distance varies significantly causing the evaluation value to drop and the focusing operation to fail
Solution Approach 1:
The patent applies dynamics by making the auto-focus process adjustable and responsive to operating conditions. The control apparatus detects pan/tilt operations and dynamically modifies the AF process accordingly, transitioning from continuous evaluation to a more selective approach that accounts for varying subject distances during camera movement.
Solution Approach 2:
The patent uses feedback by detecting changes in operating conditions (pan/tilt operations) and using this information to control the auto-focus process. The control apparatus receives feedback about camera movement and adjusts the AF evaluation and execution accordingly, preventing unnecessary or failed focusing operations.
2Measurement precision
If the lens is moved to be in focus on the subject while viewing the captured image, then accurate focusing can be achieved, but a length of time is required before the AF process is completed
Solution Approach 1:
The patent applies preliminary action by detecting pan/tilt operations in advance and preemptively controlling the AF process. When camera movement is detected, the system prepares by suppressing or modifying the AF process before the evaluation value drops and focusing failure occurs, thereby maintaining accuracy while reducing unnecessary time consumption.
3Reliability
If the image pickup apparatus evaluates the out-of-focus level continuously and starts one-shot AF process when evaluation value changes meet threshold, then the apparatus can continuously be in focus on subject, but unnecessary focusing operations occur during panning causing focus instability
Solution Approach 1:
The patent uses feedback by detecting operating conditions (pan/tilt operations) and using this information to control when AF evaluation and execution occur. The control apparatus receives feedback about camera movement and adjusts the AF process accordingly, suppressing evaluation during movements that would cause focus instability while maintaining it during stable shooting conditions.
Data Source
AI summary
A control apparatus for controlling a driver driving an optical element of an image pickup device to adjust a focus position of the image pickup device in the capturing of an image of a subject, includes a relative angle variation calculating unit for calculating a relative angle variation, a mode change detecting unit for detecting of a change of a mode of the relative angle variation through determining whether the mode of the relative angle variation, calculated by the relative angle variation calculating unit, is a stable mode involving a small amount of change or an unstable mode involving a large amount of change, and a focus position control process startup unit for managing a startup of a focus position control process controlling the focus position through controlling the driver in response to a pattern of the change of the mode detected by the mode change detecting unit.