Ocular Imaging Illumination in Image Path
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Solution Overview
Problem
Retinal imaging technologies face challenges with bright illumination causing optical aberrations such as lens flare and corneal reflections, which degrade image quality despite improving fidelity.
Innovation Solution
The implementation of a dynamic illuminator positioned in the image path, allowing for focal stacking and removal of image artifacts, and increasing the eyebox by using multiple illumination positions and a beam splitter to reduce reflections and enhance image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If bright illumination is used to improve retinal image fidelity, then image brightness and fidelity are improved, but optical aberrations such as lens flare and corneal reflections increase
Solution Approach 1:
The illumination function is segmented from the imaging path by using a separate illumination source positioned at a 45-degree angle to the optical axis, with illumination delivered through a beam splitter. This separates the illumination light path from the imaging light path, allowing independent optimization of illumination intensity without directly increasing aberrations in the imaging path.
Solution Approach 2:
A beam splitter acts as an intermediary component to deliver illumination light to the retina while allowing the imaging path to remain separate. The beam splitter mediates between the illumination source and the optical system, enabling bright illumination without directly introducing aberrations into the imaging path.
2Productivity
If a single image capture is used to reduce exposure time, then productivity is improved, but image quality is degraded due to unavoidable artifacts
Solution Approach 1:
The system uses periodic action by capturing multiple images in rapid succession and combining them through focal stacking. The illuminator activates in synchronized periodic intervals with the camera capture sequence, allowing multiple images to be acquired quickly and combined to eliminate artifacts while maintaining high productivity.
Solution Approach 2:
Preliminary action is applied by capturing multiple images before final composite image generation. The system pre-captures a sequence of images with the illuminator activated, then processes them through focal stacking to remove artifacts, ensuring high-quality output without sacrificing imaging speed.
3Object-affected harmful factors
If a small aperture is used to block corneal reflections, then optical aberrations are reduced, but the eyebox size is reduced
Solution Approach 1:
The illumination geometry is changed by positioning the illuminator at a 45-degree angle to the optical axis rather than coaxially. This dimensional change in illumination geometry allows the use of a larger aperture without corneal reflections entering the imaging path, as the reflected light is directed away from the optical axis.
Solution Approach 2:
The beam splitter serves as an intermediary that allows the illumination path and imaging path to be separated spatially. This enables the use of a larger aperture for better eyebox without compromising the ability to block corneal reflections, as the beam splitter directs illumination light separately from the imaging path.
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 results in high-fidelity retinal images with reduced optical aberrations, enabling accurate screening and diagnosis by combining multiple images to form a composite image with improved depth of field and reduced artifacts.
Implementation Method 1
a beam splitter to reduce reflections
Implementation Method 2
Bright illumination of the posterior interior surface of the eye (i.e., retina) through the pupil
Data Source
AI summary
An apparatus for imaging an interior of an eye includes a light sensitive sensor, and a housing structure with an opening defining an imaging area to place the eye for imaging by the light sensitive sensor. One or more light emitters (LEs) are disposed in an image path between the light sensitive sensor and the eye during capture of a plurality of images. A controller is coupled to the plurality of LEs and the light sensitive sensor. The controller implements logic that when executed by the controller causes the apparatus to perform operations including: illuminating the imaging area with the one or more LEs; and capturing, with the light sensitive sensor, the plurality of images of the interior of the eye at the same time as the eye is illuminated with the light from the one or more LEs.