Optical Interference Measuring Apparatus for Folded Image Correction
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Solution Overview
Problem
In swept source optical coherence tomography (SS-OCT) measurements, the detection of folded images due to reflecting surfaces closer to the light source than the zero point leads to erroneous tomographic images, limiting the measurable range and requiring accurate adjustment of the optical path length of the reference light, which is challenging when the position of the reflecting surface is unknown or not accurately known.
Innovation Solution
An optical interference measuring method and apparatus that split light into measuring and reference light, detect coherent light from the interference, and adjust the optical path length of the reference light to differentiate between normal and folded images, using an optical-path length adjustment mechanism to correct for image orientation and position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the optical path length of reference light is not accurately adjusted, then the measurable range is limited and folded images occur, but accurate adjustment is challenging when the position of the reflecting surface is unknown
Solution Approach 1:
The patent applies preliminary action by automatically adjusting the optical path length of reference light before measurement begins. The arithmetic and control unit performs preliminary adjustment based on initial detection results, ensuring the system is properly configured before actual measurement, thus eliminating the need for manual pre-adjustment when the reflecting surface position is unknown
Solution Approach 2:
The patent implements feedback by using the detected coherent light signal to continuously monitor and adjust the optical path length. The arithmetic and control unit receives feedback from the detection unit and automatically modifies the optical path length to maintain optimal measurement conditions, resolving the contradiction between measurement accuracy and adjustment complexity
2Reliability
If the optical path length of reference light is adjusted to eliminate folded images, then image orientation can be corrected, but the measurable range is limited without such adjustment
Solution Approach 1:
The patent applies dynamics by making the optical path length adjustable and changeable during measurement. The arithmetic and control unit dynamically modifies the optical path length based on detection results, allowing the system to adapt between different measurement scenarios (normal images vs. folded images) and thus maintaining both reliability and measurable range
Solution Approach 2:
The patent implements parameter changes by varying the optical path length of reference light to transform folded images into normal images. By changing this critical parameter, the system can correct image orientation while maintaining the ability to measure different depths, thus resolving the contradiction between reliability and adaptability
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 accurate differentiation between normal and folded images, allowing for precise adjustment and correction of tomographic images, thereby overcoming the limitations of measurable range and image orientation issues in SS-OCT measurements.
Implementation Method 1
coherent light obtained by interference of the reference light and the measuring light reflected from or scattered rearward from a measuring object
Data Source
AI summary
In an optical interference measuring method according to the present invention, light emitted from a light source unit is split into measuring light and reference light, coherent light is detected that is obtained by interference of the reference light and the measuring light reflected from or scattered rearward from a measuring object, an optical-path length adjustment mechanism provided in the optical path of the reference light is driven to change the optical path length of the reference light, it is decided whether an image based on the detected coherent light is a normal image or a folded image based on the coherent light having varied with the change of the optical path length of the reference light, and the measuring object is measured from the detected coherent light based on a result of the decision about whether the image is a normal image or a folded image.