Wide Field Fundus Camera Auto Montage Alignment
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Solution Overview
Problem
Conventional wide field fundus cameras face challenges in achieving a wide enough field of view for accurate retinal examination, particularly in adults with less transparent crystalline lenses, and struggle with image haze and autofocus speed, which hinders efficient detection of retinal pathologies like ROP.
Innovation Solution
The implementation of multiple illumination beam projectors positioned axially symmetrically around the viewing axis, combined with an ultra-wide field lens and real-time dehazing algorithms, enables edge-to-edge observation of the retina with improved autofocus and image clarity, facilitating rapid and reliable retinal imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If an illumination ring is used to provide uniform illumination over a field of view, then a 120-degree FOV can be achieved, but image clarity deteriorates when the crystalline lens is less transparent and Purkinje reflection images become visible
Solution Approach 1:
The single illumination ring is divided into multiple separate illumination beams positioned at different locations. Each beam illuminates a specific region of the retina, and by selectively activating different beams, the system achieves wide field of view while avoiding Purkinje reflections in the imaging path. This segmentation allows the illumination and imaging functions to operate independently without mutual interference.
Solution Approach 2:
Different regions of the retina are illuminated with different quality and intensity characteristics. The illumination beams are positioned and configured to provide optimal illumination for specific retinal zones while minimizing unwanted reflections. This local optimization allows clear imaging of the retina without the degradation caused by universal illumination approaches.
2Area of stationary object
If a 130-degree FOV device is used to image the entire retina, then edge to edge observation is possible, but the examination becomes time-consuming requiring 6 to 8 separate images at multiple tilt positions
Solution Approach 1:
The retinal examination field is segmented into multiple zones, each illuminated by a dedicated illumination beam. By activating multiple beams simultaneously or in rapid succession, the system captures multiple retinal regions in a single examination session, eliminating the need for repeated tilting and repositioning. This achieves comprehensive retinal coverage while maintaining high examination efficiency.
Solution Approach 2:
The fundus camera system is designed to perform multiple functions: it can image different retinal regions, provide various illumination patterns, and capture images at different angles all within a single device configuration. This multi-functionality allows the system to achieve edge-to-edge retinal observation without requiring multiple separate imaging sessions or device repositioning.
3Measurement precision
If multiple illumination beam projectors are used to achieve wide field of view, then device complexity increases, but image clarity and autofocus performance improve
Solution Approach 1:
The illumination system is segmented into multiple independent beam projectors, each with its own optical path and control. This modular segmentation allows the system to achieve superior image clarity through multiple illuminated zones while managing complexity by treating each beam as an independent unit that can be controlled and optimized separately.
Solution Approach 2:
The multiple illumination beams provide self-aligning reference features that enable automatic focusing and alignment procedures. The system uses the illumination patterns themselves to guide the autofocus mechanism, eliminating the need for separate alignment tools or complex manual adjustment procedures, thereby managing device complexity through self-service capabilities.
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 allows for a 180-degree field of view, enhanced image clarity by reducing haze, and fast autofocus, enabling quick and accurate retinal examinations, particularly in infants and adults with less transparent lenses, thereby improving the detection of retinal pathologies.
Implementation Method 1
an aspherical lens having a symmetric viewing axis and disposed to form a retinal image
Implementation Method 2
a mechanism of cross polarization configured between said image recording device and said plurality of illumination beam projectors to reject specular reflections of said illumination beams
Implementation Method 3
a first source configured to provide a plurality of illumination beam projectors positioned around said viewing axis and projected each at an angle toward said aspherical lens
Data Source
AI summary
A wide field fundus camera having multiple illumination beam projectors and to capture multiple retinal images at various viewing angles to facilitate wide field retinal examination. The wide field fundus camera images an entire retina at a single alignment. The wide field fundus camera provides visualization of a retina and Purkinje reflections simultaneously to facilitate alignment. The wide field fundus camera further contemplates narrow and broad slit beam illuminations to enhance autofocusing, imaging through less transparent crystalline lens, and reduction of haze due to reflected and scattered light from camera and ocular surfaces other than the retina. The wide field camera contemplates a real-time algorithm to reduce said reflected and scattered light haze in said retinal images. The wide field camera further contemplates automated montage of said multiple retinal images into a single wide field FOV retinal montage and automated removal reflected and scattered light haze from said retinal montage.