Retinal Image Generator Positional Displacement Detection
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Solution Overview
Problem
Existing optical coherence tomography (OCT) devices face challenges in precisely detecting the movement of the retina during scanning, leading to difficulties in generating high-quality three-dimensional images due to the influence of speckle noise and the need for complex configurations.
Innovation Solution
A device with a first light source unit, light divider, reference light beam unit, measurement unit, interference intensity detector, second light source unit, and positional displacement detector, which uses a single light control mechanism and controller to adjust scanning positions and detect scanning position displacement, thereby reducing speckle noise and improving image alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional OCT device is used to scan the retina, then a three-dimensional image can be generated, but the retina movement causes scanning position displacement leading to image distortion and speckle noise
Solution Approach 1:
The patent uses a line beam as a reference copy to track retina movement. By projecting a line beam along the same optical path as the scanning beam and detecting its reflected position with a line sensor, the system creates a reference measurement that copies the actual scanning path, enabling precise detection of scanning position displacement without adding complex measurement equipment
Solution Approach 2:
The patent introduces a line beam as an intermediary element between the scanning system and the retina. This line beam serves as a mediator that carries information about scanning position changes, allowing the system to detect displacement through the position of the reflected line beam on the line sensor without directly measuring the scanning beam's position
2Reliability
If multiple images are averaged to reduce speckle noise, then image quality improves, but misalignment due to scanning position displacement reduces the effectiveness of averaging
Solution Approach 1:
The patent implements a feedback mechanism where the detected line beam position information is used to correct scanning position displacement. The system continuously monitors the line beam position, calculates displacement, and feeds this information back to adjust subsequent scanning positions, ensuring that multiple images remain aligned for effective averaging to reduce speckle noise
3Productivity
If the scanning speed is increased to reduce measurement time, then productivity improves, but the ability to detect and correct scanning position displacement deteriorates
Solution Approach 1:
The patent ensures continuous detection of scanning position displacement by maintaining constant projection of the line beam and continuous monitoring with the line sensor throughout the scanning process. This continuous measurement approach allows the system to detect and correct displacement even at high scanning speeds, maintaining precision without sacrificing productivity
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 device enables precise detection of scanning position displacement, reduces image distortion, and achieves high-quality retinal images with minimal speckle noise by using a simple configuration that aligns multiple images accurately.
Implementation Method 1
a light divider that divides an output light beam output from the first light source into an object-scanning light beam that is delivered to a retina of an eye ball and a reference light beam for reference
Implementation Method 2
a reference light beam unit, into which the reference light beam is input and that causes the input reference light beam to reflect as a reference reflection light beam
Implementation Method 3
a measurement unit that scans the retina by the object-scanning light beam and that causes light scattered at the retina to reflect as an object-reflected light beam
Implementation Method 4
an interference intensity detector that generates an interference light beam in which the reference reflection light beam and the object-reflected light beam are caused to interfere with each other
Implementation Method 5
a second light source unit that has a second light source for outputting a line beam and that outputs the line beam in order to transmit the line beam in a path identical to that of the object-scanning light beam in the measurement unit
Implementation Method 6
a positional displacement detector that has a line sensor, that detects the line beam reflected from the retina and output from the measurement unit by the line sensor and that detects scanning position displacement during scanning of the retina by the object-scanning light beam
Data Source
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Figure 2A~2B
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AI summary
Provided is a three-dimensional retina image generator that can detect, in a precise manner, the scanning position displacement during scanning of the retina with a simple configuration and, as a result, and can obtain a high-quality retinal image with a reduced influence of speckle noise therein. In order to detect the movement of retina R, the three-dimensional retina image generator has: second light source unit 210 that outputs a line beam to be imaged on retina R; positional displacement detector 220 that detects the line beam reflected from retina R and that detects the "displacement" of the scanning position during scanning of retina R; and dichroic mirror 230 that causes the line beam to propagate along the same light path as that of the object light scanning beam in inspection unit 140.