Fundus Imaging Light Synchronization for Microcoria Eye States
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Solution Overview
Problem
Existing ophthalmic apparatuses face challenges in acquiring high-quality images of the eye, particularly in conditions where the pupil is microcoria, leading to reduced light entry and degraded image quality, and are not effectively adaptable to varying eye states such as dioptric power.
Innovation Solution
An ophthalmic apparatus with a slit-shaped illumination system, including an iris aperture and optical scanner, uses a rolling shutter method to control the image sensor, allowing for synchronized movement of the illumination light and readout of returning light to capture high-quality images of the fundus, regardless of eye state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional illumination systems are used, then the apparatus can operate with simple configuration, but image quality degrades when pupil is microcoria due to reduced light entry
Solution Approach 1:
The illumination system is segmented into multiple functional components: a light source, a movable slit that defines the illumination pattern, and an iris aperture that controls the beam diameter. This segmentation allows independent optimization of each component to maximize light entry while maintaining manageable system complexity.
Solution Approach 2:
The slit and iris aperture are made movable along the optical axis, allowing dynamic adjustment of the illumination beam parameters. This dynamic capability enables the system to adapt to varying eye conditions (such as microcoria) by optimizing light entry in real-time, thereby improving image quality without requiring a completely complex fixed system.
2Adaptability or versatility
If the apparatus uses fixed illumination parameters, then the system remains simple, but it cannot adapt to varying eye states such as dioptric power
Solution Approach 1:
The movable slit and iris aperture enable dynamic adjustment of illumination parameters based on detected eye state. The system can adapt to varying dioptric power and other eye conditions by repositioning these components, providing versatility without requiring completely separate systems for each eye state.
Solution Approach 2:
The system detects the eye state (such as dioptric power) and uses this information to control the position of the slit and iris aperture. This feedback mechanism allows the apparatus to automatically adapt to varying eye conditions, improving versatility while keeping the control mechanism manageable through automated adjustment.
3Measurement precision
If the image sensor reads out all pixels simultaneously, then the acquisition is simple, but it cannot capture synchronized illumination patterns for high-quality imaging
Solution Approach 1:
The image sensor is controlled to read out pixel data in a segmented manner corresponding to the illuminated region defined by the slit. Rather than reading out all pixels simultaneously, the system selectively reads out only the relevant pixel rows that correspond to the illuminated area, thereby capturing synchronized illumination patterns for high-quality imaging while managing sensor control complexity.
Solution Approach 2:
The system performs preliminary actions by controlling the slit and iris aperture to define the illumination pattern before the image sensor reads out the pixel data. This preliminary configuration ensures that only the relevant illuminated region is captured, improving image quality through synchronized illumination and detection while simplifying the overall control process.
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 apparatus achieves high-quality imaging of the fundus with strong contrast by optimizing light distribution and synchronization, effectively addressing issues of reduced light entry and varying eye conditions.
Implementation Method 1
an optical scanner configured to deflect the illumination light to guide the illumination light to a fundus of a subject's eye
Implementation Method 2
an imaging optical system configured to guide returning light of the illumination light from the fundus to an image sensor
Data Source
AI summary
An ophthalmic apparatus includes a light source, an illumination optical system, an optical scanner, an imaging optical system, and a controller. The illumination optical system generates slit-shaped illumination light using light from the light source. The optical scanner guides the illumination light to a fundus of a subject's eye. The imaging optical system guides returning light of the illumination light from the fundus to an image sensor. The controller controls the image sensor using a rolling shutter method. The illumination optical system includes a slit with a slit-shaped aperture arranged at a position substantially conjugate optically to the fundus, an iris aperture arranged between the light source and the slit, and capable of being arranged at a position substantially conjugate optically to an iris of the subject's eye; and an optical element arranged between the light source and the iris aperture to deflect the light from the light source.