Multi-Spectral Fundus Imaging with Sequential LED Illumination
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Solution Overview
Problem
Current ophthalmologic devices face challenges in capturing high-resolution, sensitive images of the retina with minimal light stress, particularly in measuring blood flow velocity and oxygen saturation, due to limitations in viewing angles, light exposure, and technical complexity.
Innovation Solution
A device and method utilizing a multi-spectral sequential illumination module with individually regulated LEDs for monochromatic light emission, synchronized with an image recording module, and a control and safety module to minimize light stress and enhance image quality, allowing for spatially resolved blood flow velocity measurement and oxygen saturation analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If broadband white light illumination is used to illuminate the retina, then the retina is illuminated over a broad band, but the light stress on the eye being examined is especially high
Solution Approach 1:
The broadband illumination is segmented into multiple narrow-band wavelength ranges, with each range captured by a dedicated sensor. This allows selective illumination at specific wavelengths rather than continuous broadband exposure, reducing overall light stress while maintaining diagnostic capability across multiple spectral bands
Solution Approach 2:
The system uses sequential illumination where different narrow-band wavelength ranges are illuminated in alternating time periods. Each wavelength range is activated periodically rather than continuously, enabling broad-spectrum imaging while minimizing cumulative light exposure to the retina
2Measurement precision
If mechanically swivelable filters are used for recording monochromatic images, then color masks can be placed on the electronic image receiving sensor, but the system requires costly filters which must be swiveled into and out of the beam path in the millisecond range
Solution Approach 1:
The mechanical filter swiveling system is replaced with an electronic wavelength selection mechanism. Multiple sensors with different spectral sensitivities capture light from a single illumination source, eliminating the need for mechanical filter movement while achieving the same narrow-band excitation precision
Solution Approach 2:
A single illumination source serves multiple functions by providing illumination for different wavelength ranges simultaneously or sequentially. Multiple sensors with different spectral characteristics replace the need for multiple filtered imaging paths, reducing mechanical complexity while maintaining multi-wavelength diagnostic capability
3Duration of action of moving object
If continuous illumination of the retina is used for optical observation, then the retina is illuminated continuously, but the light stress on the eye being examined is especially high
Solution Approach 1:
Illumination is applied periodically in pulses corresponding to the sequential activation of different wavelength ranges, rather than continuously. The timing is synchronized with the sensor readout cycle, providing sufficient illumination duration for each wavelength band while minimizing total exposure time
Solution Approach 2:
Each individual wavelength range receives partial illumination exposure rather than full continuous illumination. The cumulative effect across multiple wavelength ranges provides comprehensive diagnostic information while keeping the exposure dose for each individual wavelength below harmful thresholds
4Measurement precision
If high resolution of 5 to 8 megapixels is used for fundus images, then high resolution images are obtained, but very high light powers must be used and sensitive sensors are often needed to register the very weak light signals
Solution Approach 1:
The high-resolution imaging task is segmented across multiple sensors with different spectral sensitivities. Each sensor captures a portion of the spectral information at lower resolution requirements, and the data is combined to achieve comprehensive diagnostic information without requiring extremely high light powers for a single 5-8 megapixel image
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
Enables sensitive, high-resolution imaging of the retina with reduced light exposure, facilitating early disease diagnosis and providing detailed information on blood flow and oxygen saturation, while simplifying the diagnostic process and reducing technical complexity.
Implementation Method 1
An illumination module which is connected to the ophthalmologic examination device has at least two individual light sources 6.1, 6.2 which can be regulated individually with respect to intensity and duration and which emit monochromatic light of different wavelengths
Implementation Method 2
The light coming from the illumination module is imaged on the image recording module from the ophthalmologic examination device by the eye being examined
Data Source
AI summary
The present invention is directed to a device and a method for the observation, documentation and/or diagnosis of the fundus in which the diagnosis is carried out by evaluating the documented images of the fundus. The device according to the invention comprises an ophthalmological examination device, a multi-spectral sequential illumination module, an image recording module, a control and safety module, and an evaluating unit. The illumination module which is connected to the ophthalmologic examination device has at least two individual light sources and which can be regulated individually with respect to intensity and duration and which emit monochromatic light of different wavelengths. The light coming from the illumination module is imaged on the image recording module from the ophthalmologic examination device by the eye being examined. The control and safety module controls the chronological sequence, duration and intensity of the individual light sources and monitors the light stress. An evaluating unit evaluates the recordings of the fundus transmitted by the image recording module. The inventive solution serves to record monochromatic images of the retina, for example, red, green, blue, or also infrared, and to record fluorescence images.