TOF Measuring Apparatus with Gas Layer Distance Correction
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Solution Overview
Problem
Existing measuring apparatuses that use time of flight (TOF) measurement for distance calculation within objects face challenges in accurately determining internal propagation distances without direct contact, especially when a gas or vacuum layer is interposed between the light source and the measurement object.
Innovation Solution
A measuring apparatus and method that utilize a light source and a light receiver separated by a gas or vacuum layer, projecting pulsed or intensity-modulated light and calculating internal propagation distances using time of flight information, along with reference distances acquired through a distance fixing mechanism, to determine optical characteristics of the measurement object.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a gas layer or vacuum layer is interposed between the light source device and the measurement object, then non-contact measurement is enabled, but measurement precision deteriorates due to the additional propagation distance through the gas or vacuum layer
Solution Approach 1:
The patent introduces a distance measuring mechanism as an intermediary to measure the distance from the light source device to the measurement object surface through the gas or vacuum layer. This measured distance is then used to correct the TOF measurement, effectively compensating for the additional propagation path and restoring measurement precision while maintaining non-contact operation.
Solution Approach 2:
The patent changes the measurement parameter by separately measuring the distance parameter through the gas/vacuum layer using the distance measuring mechanism. This allows the system to account for the gas/vacuum layer thickness as a correction parameter in the TOF measurement calculation, thereby improving internal propagation distance measurement accuracy.
2Adaptability or versatility
If the light source device and light receiver are arranged with a gas layer or vacuum layer between them, then the measurement object can be measured without direct contact, but the device complexity increases due to the need for additional distance measurement and correction mechanisms
Solution Approach 1:
The patent makes the distance measuring mechanism multi-functional by using it for both determining the external distance (through gas/vacuum layer) and correcting the TOF measurement. This universal approach allows a single additional component to serve multiple purposes, reducing the net increase in device complexity while maintaining versatility.
Solution Approach 2:
The system implements feedback by using the distance measured through the gas/vacuum layer to correct the TOF measurement results. The distance measuring mechanism provides feedback information about the external path length, which is then fed back into the calculation to determine the internal propagation distance, thereby reducing overall system complexity through intelligent correction.
3Productivity
If TOF measurement is used to measure internal propagation distance, then measurement speed is improved, but measurement precision deteriorates when a gas layer or vacuum layer is present due to refractive index differences
Solution Approach 1:
The distance measuring mechanism acts as an intermediary that measures the external distance through the gas/vacuum layer separately. This measurement serves as a correction factor that compensates for the refractive index differences and additional path length, thereby maintaining both high measurement speed and precision in TOF measurements.
Solution Approach 2:
The system performs preliminary measurement of the distance through the gas/vacuum layer before the main TOF measurement. This preliminary action allows the system to pre-calculate correction factors that will be applied during the TOF measurement, ensuring that the final internal propagation distance measurement is accurate while maintaining fast measurement speed.
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 non-contact measurement of internal distances and optical characteristics within objects, improving accuracy and applicability across various measurement scenarios.
Implementation Method 1
time of flight (TOF) measurement is used, and there are known a method of periodically modulating intensity of light projected from a light source and measuring a distance of propagation of light inside of a measurement object from a phase shift of intensity modulation between the light projected and light returning from the subject and a method of measuring a light propagation distance from a time delay until a short pulse is projected from the light source and light returning from the subject is received
Implementation Method 2
calculate an internal propagation distance in the measurement object according to the measured TOF information and the acquired distances
Data Source
AI summary
A measuring apparatus includes: a light source device that projects light or light of which intensity is periodically modulated onto a measurement object; a light receiver that receives backscattered light of light projected by the light source device from the measurement object; and a processor comprising hardware, the processor being configured to: measure TOF information of the light projected by the light source device and the backscattered light received by the light receiver; acquire distances from a surface of the measurement object to the light source device and the light receiver; and calculate an internal propagation distance in the measurement object according to the measured TOF information and the acquired distances.