Endoscope Branch Optical System for Accurate TOF Distance Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current endoscopic distance measurement technologies, such as the single-lens Time Of Flight (TOF) system, fail to provide accurate distance information for living tissues due to reduced ranging light efficiency and optical path differences, resulting in insufficient accuracy for surgical applications.
Innovation Solution
An imaging device with a branch optical system that coaxes incident light into three optical paths, allowing controlled ranging light application and optical feedback imaging, enabling accurate distance calculation using the Time Of Flight method, regardless of endoscope diameter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a single-lens Time Of Flight (TOF) system is used for distance measurement in endoscopy, then the system can be implemented in small-diameter endoscopes, but the ranging accuracy deteriorates to approximately 3.3 mm standard deviation which is insufficient for surgical applications
Solution Approach 1:
The patent divides the optical system into multiple functional segments: a light guide section for emitting ranging light, a separate imaging section for detecting reflected light, and a dedicated TOF measurement section. This segmentation allows each component to be optimized for its specific function, improving overall measurement precision while maintaining compact dimensions suitable for small-diameter endoscopes.
Solution Approach 2:
The patent introduces a light guide as an intermediary component that efficiently transmits ranging light from the light source to the target tissue and returns reflected light to the detector. This intermediary structure improves light collection efficiency and signal-to-noise ratio, thereby enhancing ranging accuracy without increasing endoscope diameter.
2Ease of manufacture
If ranging light is applied from an illumination port different from the observation optical path, then the system can be implemented, but the ranging accuracy deteriorates due to optical path differences and reduced light efficiency
Solution Approach 1:
The patent merges the ranging light path and observation optical path into a coaxial arrangement, where both functions share the same optical axis. This merging eliminates optical path differences between illumination and detection, improves light efficiency by utilizing the same optical channel, and maintains ease of implementation through integrated lens design.
Solution Approach 2:
The patent designs the optical system to perform multiple functions through a unified structure: the same optical path serves both for delivering ranging light and for collecting reflected light for TOF measurement. This multi-functional design improves measurement precision while keeping the system implementation straightforward.
3Loss of information
If a twin-lens stereo system through use of parallax is used for distance measurement, then distance information can be obtained, but the device complexity increases and it cannot be applied to small-diameter endoscopes due to space requirements
Solution Approach 1:
The patent extracts the distance measurement function from the complex twin-lens stereo system and implements it through a simplified single-lens TOF approach. By taking out only the essential ranging capability and implementing it through time-of-flight measurement with a single optical path, the system reduces complexity while maintaining the ability to obtain distance information.
Solution Approach 2:
The patent replaces the mechanical/optical complexity of a twin-lens stereo system with an electronic/time-based TOF measurement system. Instead of using parallax from multiple lenses, the system uses time-of-flight measurement of light, substituting a mechanically complex optical arrangement with a more compact electronic timing-based approach that is suitable for small-diameter endoscopes.
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 solution achieves higher accuracy in distance measurement for living tissues during endoscopic procedures, improving the precision of surgical determinations and treatments.
Implementation Method 1
the distance information calculating section calculates a spaced distance to the imaging target by a Time Of Flight method on the basis of the result of detection of the optical feedback
Implementation Method 2
a ranging light image sensor on which optical feedback of the ranging light from the imaging target is imaged
Data Source
AI summary
[Object] To acquire distance information concerning a living tissue through an endoscope with higher accuracy irrespective of the diameter of the endoscope.[Solution] An imaging device according to the present disclosure includes: a ranging light source section configured to output ranging light for measuring a distance at a predetermined timing; an image sensor on which an image of the imaging target is formed; a ranging light image sensor on which optical feedback of the ranging light from the imaging target is imaged; a branch optical system configured to coaxially branch incident light into three types of optical paths different from one another; and a distance information calculating section configured to calculate distance information concerning the imaging target on a basis of a result of detection of the optical feedback. In the branch optical system, a first optical path among the three types of optical paths is used as an optical path configured to guide the ranging light whose applied position on the imaging target has been controlled to the imaging target, a second optical path is used as an optical path configured to form an image of the imaging target on the image sensor, and a third optical path is used as an optical path configured to image the optical feedback on the ranging light image sensor. The distance information calculating section calculates a spaced distance to the imaging target by a Time Of Flight method on the basis of the result of detection of the optical feedback.