Ophthalmic Imaging Apparatus with Parallel Focus Control for Wide-Angle OCT
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Solution Overview
Problem
The challenge in ophthalmic imaging is to acquire high-quality OCT images while performing wide-angle scans at high speeds, as image quality deteriorates in peripheral areas due to ocular optical system aberrations, and conventional focus control is too slow to keep pace with rapid OCT scanning.
Innovation Solution
An ophthalmic imaging apparatus that includes a data acquiring unit for OCT scans, an image constructing unit, a focal position changing unit, and a scan controller to control the scan pattern with distinct focal positions for central and peripheral regions, allowing for parallel focus control during scanning, and a movement detecting processor to adjust for eye movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a wide-angle OCT scan is performed at high speed, then the scan area is enlarged and productivity is improved, but image quality deteriorates in peripheral areas due to ocular optical system aberrations
Solution Approach 1:
The scan area is divided into a central region and a peripheral region, with different focal positions assigned to each region. The central region uses a first focal position optimized for central vision, while the peripheral region uses a second focal position that compensates for optical aberrations in that area. This segmentation allows high-speed wide-angle scanning while maintaining image quality in both regions.
Solution Approach 2:
Different focal positions are applied to different regions of the scan area based on the local optical characteristics. The focal position is locally optimized for each region (central vs. peripheral) rather than using a single global focal position, thereby maintaining high image quality across the entire wide-angle field of view during high-speed scanning.
2Manufacturing precision
If conventional focus control is applied to correct aberrations, then image quality may be improved, but the control speed is too slow to keep pace with rapid OCT scanning
Solution Approach 1:
Multiple focal positions are pre-calculated and stored based on the known optical characteristics of the eye and the planned scan pattern. During high-speed OCT scanning, the appropriate pre-calculated focal position is selected and applied without requiring real-time focus adjustment. This preliminary preparation eliminates the speed bottleneck of conventional real-time focus control while maintaining image quality.
Data Source
AI summary
In an ophthalmic imaging apparatus of some aspect examples, a data acquiring unit acquires data by applying an OCT scan to an eye. An image constructing unit constructs an image from the data acquired. A focal position changing unit is provided to the measurement arm. A scan controller controls the data acquiring unit according to a scan pattern including first and second partial patterns that are continuous patterns for central and peripheral regions of an OCT scan application area, respectively. A focus controller controls the focal position changing unit such that a first focal position is applied in parallel with an OCT scan of at least part of the first partial pattern and a second focal position is applied in parallel with an OCT scan to at least part of the second partial pattern.