Retinal Camera Focal Stacking Undilated Pupil Imaging
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Solution Overview
Problem
Current retinal imaging techniques face challenges with optical aberrations and image artifacts such as lens flare, which degrade image quality, and require pupil dilation that is inconvenient and limits the depth of field.
Innovation Solution
The implementation of focal stacking and point illumination techniques allows for the creation of high-quality retinal images with a larger depth of field, even with an undilated pupil, by combining multiple images taken at different focus distances and using a high frame rate retinal camera system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If bright illumination is used to improve image fidelity, then image quality improves, but lens flare and optical aberrations worsen
Solution Approach 1:
The illumination is segmented into multiple discrete point sources arranged in a specific pattern, rather than using a single broad illumination source. This segmentation allows the light to be delivered more efficiently to the retina while reducing scattered light and lens flare artifacts.
Solution Approach 2:
The illumination pattern provides non-uniform local quality with specific point sources positioned to optimize retinal illumination while minimizing artifacts. The point illumination pattern creates localized bright spots that illuminate the retina effectively without the broad scattered illumination that causes lens flare.
2Use of energy by moving object
If pupil dilation is performed to increase light entry, then more light reaches the retina, but depth of field decreases and the process becomes more time-consuming
Solution Approach 1:
The system changes the illumination parameters by using high-intensity point sources that can effectively illuminate the retina even through a constricted pupil. This parameter change allows adequate retinal imaging without requiring pupil dilation, thereby reducing imaging time and improving ease of operation.
3Use of energy by moving object
If pupil dilation is performed to increase light entry, then more light reaches the retina, but depth of field decreases
Solution Approach 1:
The use of multiple segmented point illumination sources creates a synthetic aperture effect that maintains depth of field while allowing light entry through a constricted pupil. Each point source contributes to the overall illumination, and their combined effect provides both adequate light transmission and extended depth of field.
Solution Approach 2:
The point illumination pattern introduces a spatial dimension arrangement that optimizes light delivery. The specific geometric arrangement of point sources in the illumination pattern creates optical paths that maintain depth of field while ensuring sufficient light reaches the retina through the undilated pupil.
4Use of energy by moving object
If pupil dilation is performed to increase light entry, then more light reaches the retina, but patient comfort decreases
Solution Approach 1:
The system changes the illumination approach from requiring mechanical/chemical pupil dilation to using high-intensity point sources that work effectively with the natural constricted pupil. This parameter change eliminates the need for dilation drops and waiting time, significantly improving patient comfort while maintaining adequate light entry for retinal imaging.
Data Source
AI summary
A system for imaging a retina of an eye includes a first lens for positioning proximate to the eye; a light source positioned to illuminate the eye when the system is aligned with the eye; an image sensor adapted to capture a retinal image of the retina through the first lens; an aperture disposed along an optical path extending from the image sensor and passing through the first lens; and a processing apparatus communicatively coupled to the image sensor and the light source, wherein the processing apparatus includes logic that when executed by the processing apparatus causes the system to perform operations including: illuminating the eye with the light source and capturing the retinal image with the image sensor.