Adaptive Optics SLO Scanner Distortion Compensation
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Solution Overview
Problem
Existing ophthalmic imaging systems face challenges in accurately compensating for image distortion caused by scanner characteristics, particularly in high-resolution adaptive optics SLO systems, where positional shifts between optical and electric sampling positions lead to image degradation, and existing methods require special hardware or chart images for compensation.
Innovation Solution
An image generation apparatus that extracts reference signals during reciprocating scanning, generates sampling data strings, evaluates correlation between forward and backward scanning data strings, and compensates the sampling reference position to assemble undistorted images without special hardware or chart images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a resonant scanner is used for high-speed 2D scanning to achieve high frame rates and large angles of view, then productivity is improved, but measurement precision deteriorates due to frequency fluctuation causing positional shifts between optical scanning and electric sampling
Solution Approach 1:
The system uses correlation calculation between forward and backward scanning data strings to detect positional shifts in real-time, then applies feedback to correct the sampling reference position, maintaining measurement precision despite scanner frequency fluctuations
Solution Approach 2:
The system performs preliminary correlation evaluation between forward and backward scanning data to predict and compensate for positional shifts before they affect image quality, preventing distortion rather than correcting it afterward
2Manufacturing precision
If the resolution of AO-SLO image is increased to achieve higher transverse resolution, then manufacturing precision is improved, but object-affected harmful factors worsen due to increased sensitivity to positional shifts between scanner and photodetector
Solution Approach 1:
The correlation-based detection system provides continuous feedback on positional alignment between scanner and photodetector, enabling real-time compensation that maintains image quality even at high resolutions where positional shifts are more critical
Solution Approach 2:
The system replaces hardware-based position detection with signal processing-based correlation analysis, substituting mechanical measurement systems with computational methods that are more precise and less susceptible to physical limitations
3Measurement precision
If a dedicated hardware configuration is used to detect scanner position with high accuracy, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The system replaces dedicated hardware position detection systems with software-based correlation analysis of scanning signals, achieving high measurement precision through signal processing rather than complex mechanical or electronic hardware
Solution Approach 2:
The system uses the scanning signals themselves to detect positional shifts, making the scanning system self-diagnosing without requiring separate detection hardware, thereby reducing device complexity while maintaining precision
4Manufacturing precision
If chart images are used for distortion compensation before imaging, then manufacturing precision is improved, but loss of time increases due to additional pre-imaging steps
Solution Approach 1:
The system performs distortion compensation calculations using correlation analysis as a preliminary step before final image construction, preparing corrected sampling reference positions in advance without requiring separate chart image acquisition
Solution Approach 2:
The system uses the scanning signals themselves as reference data for correlation analysis, eliminating the need for separate chart images or external reference objects, thereby reducing time loss while maintaining compensation accuracy
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively compensates for scanner-induced distortion, improving image quality by ensuring accurate positional alignment and reducing false detection of distortion, thus enhancing the clarity of fundus images without the need for additional hardware or chart images.
Implementation Method 1
each of which has a photoelectric conversion unit which receives return light of measurement light used by a scanner to scan a region of an eye to be inspected and converts the return light into an electric signal
Data Source
AI summary
A processor extracts a reference signal of a scanner included in an adaptive optics SLO apparatus output while the scanner performs reciprocating scanning on a region of an eye to be inspected, generates sampling data strings of reciprocating scanning for individual imaging units included in the adaptive optics SLO apparatus using the reference signal as a sampling reference position, and compares, among the sampling data strings of the reciprocating scanning, a sampling data string of forward scanning with a sampling data string of backward scanning so as to evaluate the correlation between the sampling data strings, compares evaluation results obtained for the individual imaging units so as to evaluate reliability, and compensates a sampling reference position based on the evaluation results. An image construction unit assembles image data to construct an image of the region of the eye based on the compensated sampling reference position for each imaging unit.