Asymmetric Fundus Imaging Optical System for Ghost Flare Reduction
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Solution Overview
Problem
Existing fundus imaging systems suffer from artifacts such as ghost flares and unnecessary light reflections due to overlapping optical paths, which degrade image quality and hinder early detection of eye diseases.
Innovation Solution
The system employs an optical configuration where the illumination optical system does not have a specific optical axis, and its optical axis does not match the imaging optical system's axis, thereby preventing overlapping optical paths and reducing artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If coaxial vertical illumination is used to simplify the optical system, then device complexity is reduced, but artifacts such as ghost flares occur due to overlapping optical paths
Solution Approach 1:
The patent applies asymmetry by deliberately misaligning the optical axes of the illumination and imaging systems. Instead of using symmetric coaxial illumination, the illumination optical axis is offset from the imaging optical axis, creating an asymmetric configuration that prevents overlapping optical paths and eliminates ghost flares while maintaining system simplicity
2Area of stationary object
If wide-angle illumination is used to improve imaging coverage, then area of stationary object increases, but optical paths of irradiation light and reflected light overlap causing ghost flares
Solution Approach 1:
The asymmetric optical axis configuration enables wide-angle illumination coverage while preventing optical path overlap. By offsetting the illumination axis from the imaging axis, the system can illuminate a broader area without the reflected light re-entering the imaging path, thus eliminating ghost flares even with wide-angle illumination
3Object-affected harmful factors
If linear polarization elements are used to shield unnecessary light, then object-affected harmful factors are reduced, but four-leaf ghost artifacts remain due to rotation of polarized light by reflection
Solution Approach 1:
The patent extracts and eliminates the root cause of artifacts by removing the overlapping optical path configuration. Instead of using polarization elements that still produce four-leaf ghosts, the invention extracts the illumination path from the imaging path through axial offset, completely eliminating both unnecessary reflections and four-leaf ghost artifacts
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 configuration effectively prevents artifacts in fundus imaging, resulting in higher image quality and improved detection of eye diseases, even with wide-angle illumination.
Implementation Method 1
an illumination optical system configured to irradiate a fundus of an eyeball of a subject with light from a light source
Implementation Method 2
light reflected by a portion of the eye other than the fundus
Data Source
AI summary
A fundus imaging apparatus includes an illumination apparatus including a light source and an illumination optical system, and an imaging apparatus including an image sensor and an imaging optical system. The illumination optical system irradiates a fundus with light from the light source. The imaging optical system forms an image of the fundus on the image sensor. An optical axis of the illumination optical system does not match an optical axis of the imaging optical system, or the illumination optical system does not have a specific optical axis.