Retina Imaging Optics Using Controlled Aberration for Wider Focus
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Solution Overview
Problem
Capturing sharp and reflection-free images from the retina of a patient's eye is challenging due to patient movement, eye refractive errors, and eye accommodation, which quickly change alignment and focus, making it difficult to achieve high-quality fundus imaging.
Innovation Solution
An ophthalmic apparatus that intentionally introduces longitudinal chromatic and spherical aberrations to form an unsharp image on the sensor, followed by digital filtering to create a sharp image, and uses a filter to emphasize in-focus images over out-of-focus ones, enhancing depth-of-field and image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional fundus cameras are used to capture retinal images, then the imaging process is simple, but the image sharpness and resolution are poor due to patient movement and eye refractive errors
Solution Approach 1:
The patent introduces longitudinal chromatic aberration and spherical aberration as controllable optical parameters to extend the depth of field. By deliberately introducing these aberrations, the system can maintain focus across a larger range of retinal distances, compensating for patient movement and refractive errors without requiring complex active focusing mechanisms.
Solution Approach 2:
The patent converts the harmful effect of optical aberrations into a beneficial feature. Instead of correcting aberrations to achieve perfect focus (which would require complex active control), the system deliberately introduces controlled aberrations to create a larger depth of field, transforming a normally detrimental optical property into a useful imaging characteristic.
2Manufacturing precision
If the depth of field is increased to capture more retinal details, then the image quality improves, but the conventional focusing mechanism becomes less effective
Solution Approach 1:
The patent converts the harmful effect of optical aberrations into a beneficial feature. Instead of correcting aberrations to achieve perfect focus (which would require complex active control), the system deliberately introduces controlled aberrations to create a larger depth of field, transforming a normally detrimental optical property into a useful imaging characteristic.
Solution Approach 2:
The patent introduces longitudinal chromatic aberration and spherical aberration as controllable optical parameters to extend the depth of field. By deliberately introducing these aberrations, the system can maintain focus across a larger range of retinal distances, compensating for patient movement and refractive errors without requiring complex active focusing mechanisms.
3Reliability
If digital filtering is applied to enhance image quality, then the signal-to-noise ratio increases, but the processing time and computational complexity increase
Solution Approach 1:
The patent performs optical aberration introduction and image capture in advance, creating a larger depth of field before digital processing is needed. This preliminary optical action reduces the burden on subsequent digital filtering operations, as the image already contains more in-focus information that can be extracted with less computational effort.
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
The method increases the depth-of-field and sharpness of retinal images, improving image quality and usability by emphasizing in-focus details through digital processing, even in the presence of aberrations.
Implementation Method 1
causing, for forming at least one image that is in focus, a longitudinal chromatic and/or spherical aberration of an optical spectrum of light received through an imaging channel of the ophthalmic apparatus from the retina
Implementation Method 2
causing, for forming at least one image that is in focus, a longitudinal chromatic and/or spherical aberration of an optical spectrum of light received through an imaging channel of the ophthalmic apparatus from the retina
Implementation Method 3
at least one image from the one or more images of the retina is filtered by a filter for further processing in a data processing unit of the ophthalmic apparatus
Data Source
AI summary
An ophthalmic apparatus comprises an optical arrangement that causes or imitates, for forming at least one image that is in focus, a longitudinal chromatic and/or spherical aberration of an optical spectrum of light, while the retina is configured to locate within a longitudinal aberration range of the aberration in response to a distance between the ophthalmic apparatus and the eye being within a working range of the ophthalmic apparatus. An image capturing arrangement captures one or more images of the retina through the imaging channel while the distance between the ophthalmic apparatus and the eye is within a working range of the ophthalmic apparatus. A filter filters at least one image from the one or more images of the retina that is in focus for further processing in a data processing unit of the ophthalmic apparatus.