Scanner Drive Delay Compensation in Ophthalmologic Imaging
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Solution Overview
Problem
Ophthalmologic apparatuses face challenges in acquiring images with minimal positional displacement due to time delays between drive instruction issuance and actual scanner position attainment, leading to potential misdiagnosis in eye examinations.
Innovation Solution
Incorporating a light scanning unit, acquisition unit, instruction unit, position detection unit, and measurement unit that measures drive time delay to synchronize image acquisition with the scanner's actual position, ensuring accurate image capture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If image acquisition is started at the same timing as scanner drive start, then the system operation is simple, but positional displacement occurs in the acquired image
Solution Approach 1:
The system performs preliminary measurement of the time delay between drive instruction issuance and actual scanner position attainment. Based on this pre-measured delay, the image acquisition timing is preliminarily adjusted to start after the delay period, ensuring the scanner has reached the instructed position before acquisition begins. This resolves the contradiction by maintaining simple synchronization control while achieving accurate image positioning through advance timing adjustment.
2Manufacturing precision
If a fixed waiting time is added after drive instruction to compensate for delay, then image position accuracy improves, but the system cannot adapt to varying delay conditions
Solution Approach 1:
The system implements feedback by continuously measuring the actual time delay between drive instruction issuance and scanner position attainment under current operating conditions. This measured delay value is fed back to adjust the image acquisition timing dynamically. This resolves the contradiction by enabling the system to adapt to varying delay conditions while maintaining accurate image positioning through real-time delay compensation.
Solution Approach 2:
The system transitions from a static fixed waiting time approach to a dynamic delay measurement and adjustment approach. The image acquisition timing is no longer fixed but is dynamically adjusted based on the currently measured delay characteristics of the scanner system. This allows the system to adapt to environmental changes, temperature variations, and scanner wear while maintaining positioning accuracy.
3Manufacturing precision
If delay measurement and dynamic timing adjustment are implemented, then image position accuracy and adaptability improve, but device complexity increases
Solution Approach 1:
The system performs self-measurement of its own delay characteristics by monitoring the timing between drive instruction issuance and actual scanner position attainment. The system uses its own operational data to automatically adjust its acquisition timing without requiring external calibration or complex control algorithms. This resolves the contradiction by implementing accurate delay compensation through a relatively simple self-measuring and self-adjusting mechanism.
Data Source
AI summary
The present invention reduces a positional displacement of an acquired image attributable to a delay from the issuance of a drive instruction to a scanner to the scanner actually reaching an instructed drive position. An ophthalmologic apparatus has a light scanning unit which scans measuring light on an eye to be examined, an acquisition unit which receives light reflected from the eye to be examined and acquires a light receiving signal, and an instruction unit which instructs the drive position of the light scanning unit. The apparatus further includes a position detection unit which detects the current position of the light scanning unit and a measurement unit which measures the drive time delay from the issuance of an instruction by the instruction until the current position reaches the instructed drive position. The acquisition unit starts acquiring the light receiving signal at timing based on the drive time delay.