Application of the Vernier method with the phase shift time of flight technique for optical metrology

2022 ◽  
Vol 149 ◽  
pp. 106807
Author(s):  
Nuno M. Gonçalves ◽  
Manuel Abreu ◽  
D. Castro Alves
Keyword(s):  
Phase Shift ◽  
Time Of Flight ◽  
Optical Metrology

CMUT Time of Flight Gas Sensor By Phase Shift Measurement

2020 ◽  
Vol MA2020-01 (31) ◽  
pp. 2323-2323
Author(s):  
Luis Iglesias ◽  
Priyadarshini Shanmugam ◽  
Jean-François Michaud ◽  
Daniel Alquier ◽  
Dominique Certon ◽  
...  
Keyword(s):  
Phase Shift ◽  
Gas Sensor ◽  
Time Of Flight ◽  
Shift Measurement

scholarly journals Application of the Vernier method for absolute distance metrology with CW TOF phase shift technique

2020 ◽  
Vol 238 ◽  
pp. 06016
Author(s):  
Nuno M. Gonçalves ◽  
Manuel Abreu ◽  
D. Castro Alves
Keyword(s):  
Phase Shift ◽  
Phase Angle ◽  
Time Of Flight ◽  
Absolute Measurement ◽  
Absolute Distance ◽  
Position Information ◽  
Residual Part ◽  
Shift Technique

A phase shift time of flight technique determines a position by comparing the phase angle of a continuously modulated signal in the source and its reflection on a target. However, due to its cyclical properties, the position information is contained within an ambiguity interval. For an absolute measurement, this interval is repeated N times plus a residual part given by the phase shift. In this work we propose an application of the Vernier method to determine N and a setup for mid-range applications (10-20) m with a 3 GHz amplitude modulated source to allow accuracies ≤ 100 μm.

scholarly journals Comparison of Time-of-Flight and Phase-Shift TLS Intensity Data for the Diagnostics Measurements of Buildings

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 353 ◽  
Author(s):  
Czesław Suchocki
Keyword(s):  
Phase Shift ◽  
Point Cloud ◽  
Laser Scanning ◽  
Time Of Flight ◽  
Chemical Properties ◽  
Scanning System ◽  
Intensity Data ◽  
Building Walls ◽  
Multiple Samples ◽  
Laser Scanning System

In recent years, the terrestrial laser scanning system (TLS) has become one of the most popular remote and nondestructive testing (NDT) methods for diagnostic measurements of buildings and structures as well as for the assessment of architectural heritage. Apart from 3D coordinates, the power of a laser beam backscattered from the scanned object can be captured by TLS. The radiometric information of the point cloud, called “intensity”, can provide information about changes in the physio–chemical properties of the scanned surface. This intensity can be effectively used to detect defects in the surfaces of walls, such as cracks and cavities, moisture, biodeterioration (mosses and lichens) or weathered parts of the wall. Manufacturers of TLS mainly use two different principles for distance measurement, time-of-flight (TOF) and phase-shift (PS). The power of energy in both types of rangefinders might be absorbed or reflected in a slightly different way and provide more or less detailed radiometric point cloud information. The main aim of this investigation is to compare TOF and PS scanners in the context of using TLS intensity data for the diagnostics of buildings and other structures. The potential of TLS intensity data for detecting defects in building walls has been tested on multiple samples by two TOF (Riegl VZ400i, Leica ScanStation C10) and two PS (Z + F 5016 IMAGER, Faro Focus3D) scanners.

Crack Size Estimation Using a Combination of Cross Correlation and Phase Shift Correction in Ultrasonic Time-of-Flight Diffraction Method

2009 ◽  
Vol 413-414 ◽  
pp. 305-312
Author(s):  
Yong Hong Zhang ◽  
Ming J. Zuo ◽  
Xiao Dong Wang
Keyword(s):  
Correlation Function ◽  
Phase Shift ◽  
Cross Correlation ◽  
Arrival Time ◽  
Time Of Flight ◽  
Crack Size ◽  
Cross Correlation Function ◽  
Maximum Peak ◽  
Time Of Flight Diffraction ◽  
Ultrasonic Time

The ultrasonic time-of-flight-diffraction (TOFD) detection method has been widely used in crack size assessment. The key issue in TOFD is to determine the arrival time of crack tip diffracted signal. In the traditional cross correlation method, the resulting maximum peak of cross correlation function between two signals indicates the time of flight between them. In practical ultrasonic measurement, the transmission wave may be distorted and phase shift may be introduced. This paper presents a method using cross correlation and phase shift correction to improve the accuracy of crack sizing in the TOFD framework. The resulting maximum peak of the cross correlation function between two signals combining with time delay introduced by phase shift determine the arrival time of diffracted signal. Experimental results are used to demonstrate the advantage of the proposed method.

scholarly journals ZigBee Ranging using Phase Shift Measurements

2015 ◽  
Vol 68 (4) ◽  
pp. 665-677 ◽  
Author(s):  
Jacek Rapinski ◽  
Michal Smieja
Keyword(s):  
Phase Shift ◽  
Time Of Flight ◽  
Measurement Data ◽  
Statistical Parameters ◽  
Distance Measurements

This paper presents the results of distance measurements performed with an AT86RF233 chip. It uses a combination of time of flight and phase shift measurements to perform ranging. The statistical parameters describing the ranging results are presented and an algorithm to process raw measurement data is proposed. The results show significant improvement in ranging accuracy.

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