Imaging Apparatus Focus Control Using Temperature Feedback
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Solution Overview
Problem
Existing imaging apparatuses face challenges in correcting defocus caused by temperature changes and subject movement, as the amount of blur varies among systems and common correction methods are insufficient.
Innovation Solution
An imaging apparatus with an acquisition unit for distance information, a control unit to adjust the focus position, and a storage unit to store reference distance information, allowing for readjustment of the focus position based on acquired data to correct defocus due to environmental changes and subject movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a common correction amount is used for focus lens position to correct blur, then the correction process is simple, but the blur cannot be corrected well because the amount of blur varies among imaging optical systems due to temperature changes
Solution Approach 1:
The patent changes the correction parameter from a fixed common correction amount to a variable correction amount based on temperature. The control unit adjusts the focus lens position by a correction amount that varies according to the detected temperature, allowing accurate compensation for thermal expansion or compression effects that differ among imaging optical systems.
Solution Approach 2:
The patent introduces a feedback mechanism where a temperature sensor detects the temperature of the imaging optical system, and the control unit uses this feedback information to adjust the focus lens position. This closed-loop control ensures that the correction amount is dynamically adapted to the actual thermal conditions, improving correction accuracy.
2Reliability
If focus position is fixed using electronic cam data for zoom tracking, then the subject remains in focus during zooming, but the focus lens may be displaced causing blur due to temperature changes
Solution Approach 1:
The patent applies preliminary anti-action by detecting temperature changes before they cause significant focus displacement. The temperature sensor continuously monitors the imaging optical system, and the control unit proactively adjusts the focus lens position in response to temperature variations, preventing defocus rather than correcting it after it occurs.
Solution Approach 2:
The patent transitions from a static focus fixation method using fixed electronic cam data to a dynamic focus control system. The control unit continuously adjusts the focus lens position based on real-time temperature detection, allowing the system to adapt to thermal expansion or compression effects that occur during operation.
3Manufacturing precision
If focus lens position is corrected for blur amount, then defocus is addressed, but the correction is insufficient when the subject moves because the blur characteristics change
Solution Approach 1:
The patent uses feedback from the temperature sensor to continuously monitor and adjust focus lens position. This feedback mechanism allows the system to adapt to changing conditions including subject movement, as the control unit responds to actual temperature variations rather than relying on predetermined correction tables.
Solution Approach 2:
The patent changes the correction approach from using fixed blur correction amounts to variable correction amounts based on temperature. This parameter change enables the system to handle different scenarios including subject movement, as the correction amount is dynamically adjusted according to the actual thermal state of the imaging optical system.
Data Source
AI summary
An apparatus includes an acquisition unit configured to acquire distance information that indicates a distance to a subject on each predetermined region in a captured image, a control unit configured to adjust a focus position, and a storage unit configured to store first distance information acquired by the acquisition unit in response to the adjusted focus position. The control unit readjusts the focus position based on the first distance information and second distance information acquired by the acquisition unit.