scholarly journals Mirau-Based CSI with Oscillating Reference Mirror for Vibration Compensation in In-Process Applications

2021 ◽  
Vol 11 (20) ◽  
pp. 9642
Author(s):  
Hüseyin Serbes ◽  
Pascal Gollor ◽  
Sebastian Hagemeier ◽  
Peter Lehmann
Keyword(s):  
Optical Path ◽  
High Temporal Resolution ◽  
Reference Mirror ◽  
Additional Information ◽  
Surface Topographies ◽  
Scanning Interferometer ◽  
Fixed Reference ◽  
Industrial Use ◽  
Distance Sensor ◽  
Vibration Compensation

We present a Mirau-type coherence scanning interferometer (CSI) with an oscillating reference mirror and an integrated interferometric distance sensor (IDS) sharing the optical path with the CSI. The IDS works simultaneously with the CSI and measures the distance changes during the depth scanning process with high temporal resolution. The additional information acquired by the IDS is used to correct the CSI data disturbed by unwanted distance changes due to environmental vibrations subsequent to the measurement. Due to the fixed reference mirror in commercial Mirau objectives, a Mirau attachment (MA) comprising an oscillating reference mirror is designed and built. Compared to our previous systems based on the Michelson and the Linnik interferometer, the MA represents a novel solution that completes the range of possible applications. Due to its advantages, the Mirau setup is the preferred and most frequently used interferometer type in industry. Therefore, the industrial use is ensured by this development. We investigate the functioning of the system and the capability of the vibration compensation by several measurements on various surface topographies.

Investigation of particulate systems using optical pathlength spectroscopy

2000 ◽  
Vol 627 ◽  
Author(s):  
Gabriel Popescu ◽  
Aristide Dogariu
Keyword(s):  
Path Length ◽  
Random Media ◽  
Michelson Interferometer ◽  
Industrial Process ◽  
Optical Path Length ◽  
Industrial Applications ◽  
Optical Path ◽  
Interference Signal ◽  
Optical Length ◽  
Reference Mirror

ABSTRACTIn many industrial applications involving granular media, knowledge about the structural transformations suffered during the industrial process is desirable. Optical techniques are noninvasive, fast, and versatile tools for monitoring such transformations. We have recently introduced optical path-length spectroscopy as a new technique for random media investigation. The principle of the method is to use a partially coherent source in a Michelson interferometer, where the fields from a reference mirror and the sample are combined to obtain an interference signal. When the system under investigation is a multiple-scattering medium, by tuning the optical length of the reference arm, the optical path-length probability density of light backscattered from the sample is obtained. This distribution carries information about the structural details of the medium. In the present paper, we apply the technique of optical path-length spectroscopy to investigate inhomogeneous distributions of particulate dielectrics such as ceramics and powders. The experiments are performed on suspensions of systems with different solid loads, as well as on powders and suspensions of particles with different sizes. We show that the methodology is highly sensitive to changes in volume concentration and particle size and, therefore, it can be successfully used for real-time monitoring. In addition, the technique is fiber optic-based and has all the advantages associated with the inherent versatility.

Introduction of Spectral Mapping through Transmission Grating, Derivative Technique of Photon Emission

2014 ◽  
Author(s):  
Thierry Parrassin ◽  
Sylvain Dudit ◽  
Michel Vallet ◽  
Antoine Reverdy ◽  
Hervé Deslandes
Keyword(s):  
Integrated Circuits ◽  
Failure Analysis ◽  
Light Emission ◽  
Photon Emission ◽  
Optical Path ◽  
Spectral Mapping ◽  
Additional Information ◽  
Transmission Grating ◽  
Emission System ◽  
Advance Knowledge

Abstract By adding a transmission grating into the optical path of our photon emission system and after calibration, we have completed several failure analysis case studies. In some cases, additional information on the emission sites is provided, as well as understanding of the behavior of transistors that are associated to the fail site. The main application of the setup is used for finding and differentiating easily related emission spots without advance knowledge in light emission mechanisms in integrated circuits.

High-speed laser interferometric distance sensor with reference mirror oscillating at ultrasonic frequencies

2019 ◽  
Vol 86 (3) ◽  
pp. 164-174 ◽  
Author(s):  
Sebastian Hagemeier ◽  
Stanislav Tereschenko ◽  
Peter Lehmann
Keyword(s):  
High Speed ◽  
Optical Measurement ◽  
Limited Range ◽  
Distance Measurement ◽  
Reference Mirror ◽  
Acquisition Rate ◽  
Measurement Systems ◽  
3D Topography ◽  
Distance Sensor ◽  
Laser Interferometric

AbstractOptical measurement systems are an important part of the portfolio of 3D topography sensors. By precise, contactless and rapid measurements these sensors constitute an alternative to tactile instruments. In this contribution the principle of a laser interferometric distance sensor is presented, which in combination with lateral scan axes acts as a topography sensor and also as distance sensor for the compensation of vibrations in a coherence scanning Linnik interferometer. An advantage of this distance sensor is its high acquisition rate of height values, which in case of working as a topography sensor enables high scan velocities as it is demonstrated at a chirp standard measured with a scan velocity of 80 mm/s. This is much higher than the scan velocity of tactile instruments, which are typically limited up to 1 mm/s. In addition, the compensation of vibration disturbances demonstrates the capability of the fast distance measurement.In contrast to other existing high-speed point sensors the relevant components are mass products. This keeps the costs of the sensor setup in a limited range. Furthermore, the sensor shows potential of much higher measurement rates than 116 kHz provided by the sensor used here.

scholarly journals Quantifying changes and trends in glacier area and volume in the Austrian Ötztal Alps (1969-1997-2006)

2009 ◽  
Vol 3 (2) ◽  
pp. 205-215 ◽  
Author(s):  
J. Abermann ◽  
A. Lambrecht ◽  
A. Fischer ◽  
M. Kuhn
Keyword(s):  
Length Change ◽  
High Temporal Resolution ◽  
Glacier Area ◽  
Thickness Change ◽  
Additional Information ◽  
Digital Elevation ◽  
Glacier Changes ◽  
The Individual ◽  
Individual Size ◽  
Area And Volume

Abstract. In this study we apply a simple and reliable method to derive recent changes in glacier area and volume by taking advantage of high resolution LIDAR (light detection and ranging) DEMs (digital elevation models) from the year 2006. Together with two existing glacier inventories (1969 and 1997) the new dataset enables us to quantify area and volume changes over the past 37 years at three dates. This has been done for 81 glaciers (116 km2) in the Ötztal Alps which accounts for almost one third of Austria's glacier extent. Glacier area and volume have reduced drastically with significant differences within the individual size classes. Between 1997 and 2006 an overall area loss of 10.5 km2 or 8.2% occurred. Volume has reduced by 1.0 km3 which accounts for a mean thickness change of −8.2 m. The availability of three comparable inventories allows a comprehensive size and altitude dependent analysis of glacier changes but lacks a high temporal resolution. For the comparison of rates of changes between the two different periods (1969 to 1997 with 1997 to 2006) we propose two approaches in this study: a) to estimate mean overall rates of changes (including a period of advance) and b) to extract periods of net-retreat by using additional information (length change and mass balance measurements). Analysis of the resulting acceleration factors reveals that the retreat of volume and mean thickness changes has accelerated significantly more than that of area changes.

Quasi-Common-Path Laser Feedback Interferometers for Precision Measurement of Non-Cooperative Targets

2008 ◽  
Vol 381-382 ◽  
pp. 49-52
Author(s):  
X.J. Wan ◽  
Shu Lian Zhang
Keyword(s):  
Optical Path ◽  
Heterodyne Detection ◽  
Reference Mirror ◽  
Phase Fluctuations ◽  
Common Path ◽  
Laser Instability ◽  
Phase Variations ◽  
Path Lengths ◽  
Contact Displacement ◽  
Feedback Light

In this paper, we report a novel quasi-common-path laser feedback interferometer (QLFI) for highly stable, high-resolution and non-contact displacement measurement. QLFI measures the displacement of the target by measuring the phase of feedback light. In addition to the target-generated feedback light (frequency shifted by 2#), a reference mirror generates a reference feedback light which is frequency shifted by #. The phase variations of both feedback lights are measured by heterodyne detection simultaneously and their difference offers the phase variations caused only by target displacement. When the optical path lengths of the reference and measuring feedback light are nearly the same, the phase fluctuations caused by the environment and laser instability are effectively removed. The heat-induced deformation of a He-Ne laser tube is successfully in-line measured using QLFI.

Investigation on Robot User Interface for Information Access

2010 ◽  
Vol 14 (3) ◽  
pp. 316-322
Author(s):  
Yasufumi Takama ◽  
◽  
Hiroki Namba
Keyword(s):  
User Interface ◽  
Mobile Phone ◽  
Information Access ◽  
Information Support ◽  
Additional Information ◽  
Physical Presence ◽  
Industrial Use ◽  
Support Facility

This paper investigates the characteristics of robots for non-industrial use such as home robots, when those are used as an interface for accessing information. Although information support is one of important capabilities home robots should have, the merits of accessing information via a robot compared with the access via PC or a mobile phone have yet to be fully explored. This paper focuses on the physical presence of robots, which is supposed to be important for robots to provide users with information. In order to investigate the merits, two experiments with participants are performed in this paper. The main contributions of the paper are the following points. First, it is shown that a robot can effectively attract the participants through movements, even though they pay less attention to it. Second, the possibility of using robot actions for providing additional information about information to be accessed by the participant is also investigated. Finally, the effect of a robot User Interface (UI) prototype on communication among users when providing information to them is also investigated. The obtained results support the significance of information support by home robots, which will be used for designing home robots with information support facility.

scholarly journals From runoff to rainfall: inverse rainfall–runoff modelling in a high temporal resolution

2015 ◽  
Vol 19 (11) ◽  
pp. 4619-4639 ◽  
Author(s):  
M. Herrnegger ◽  
H. P. Nachtnebel ◽  
K. Schulz
Keyword(s):  
Daily Rainfall ◽  
Inverse Model ◽  
High Temporal Resolution ◽  
Rainfall Runoff ◽  
Time Step ◽  
Lumped Model ◽  
Additional Information ◽  
Mountainous Regions ◽  
Hourly Data ◽  
Areal Rainfall

Abstract. Rainfall exhibits a large spatio-temporal variability, especially in complex alpine terrain. Additionally, the density of the monitoring network in mountainous regions is low and measurements are subjected to major errors, which lead to significant uncertainties in areal rainfall estimates. In contrast, the most reliable hydrological information available refers to runoff, which in the presented work is used as input for an inverted HBV-type rainfall–runoff model that is embedded in a root finding algorithm. For every time step a rainfall value is determined, which results in a simulated runoff value closely matching the observed runoff. The inverse model is applied and tested to the Schliefau and Krems catchments, situated in the northern Austrian Alpine foothills. The correlations between inferred rainfall and station observations in the proximity of the catchments are of similar magnitude compared to the correlations between station observations and independent INCA (Integrated Nowcasting through Comprehensive Analysis) rainfall analyses provided by the Austrian Central Institute for Meteorology and Geodynamics (ZAMG). The cumulative precipitation sums also show similar dynamics. The application of the inverse model is a promising approach to obtain additional information on mean areal rainfall. This additional information is not solely limited to the simulated hourly data but also includes the aggregated daily rainfall rates, which show a significantly higher correlation to the observed values. Potential applications of the inverse model include gaining additional information on catchment rainfall for interpolation purposes, flood forecasting or the estimation of snowmelt contribution. The application is limited to (smaller) catchments, which can be represented with a lumped model setup, and to the estimation of liquid rainfall.

scholarly journals Two-Wavelength Laser Interferometer System Which Reduces the Uncertainty Caused by the Fluctuation of the Refractive Index of Air

2011 ◽  
Vol 5 (2) ◽  
pp. 126-131 ◽  
Author(s):  
Kaoru Miyata ◽  
◽  
Hidekazu Oozeki ◽  
Hideyuki Nakagawa ◽  
Hiroki Masuda ◽  
...  
Keyword(s):  
Refractive Index ◽  
Uncertainty Analysis ◽  
Measurement Accuracy ◽  
Laser Interferometer ◽  
Optical Path ◽  
Highly Sensitive ◽  
Industrial Use ◽  
Laser Interferometers ◽  
532 Nm

Laser interferometers are widely used to measure highly sensitive length and displacement, e.g., in which refractive index fluctuations of air adversely affect measurement accuracy. To compensate for these effects, the two-wavelength interferometer studied has not yet proved practical in industrial use. We studied the interferometer’s performance and practicality, using uncertainty analysis to extract its features. Based on our results, we developed a two-wavelengthMichelson interferometer with wavelengths of 1064 nm and 532 nm. It was calibrated and evaluated using a highprecision laser interferometer whose optical path was in a vacuum. Results confirmed measurement accuracy of 100 nm/50 mm (k=2) under unstable air conditions - superior to a traditional laser interferometer.

Real-time assessment of temporomandibular joint using HASTE sequences: feasibility and comparison with standard static sequences

2020 ◽  
pp. 20200232
Author(s):  
Marco Ravanelli ◽  
Luca Bottoni ◽  
Irene Buffa ◽  
Elena Tononcelli ◽  
Andrea Borghesi ◽  
...  
Keyword(s):  
Image Quality ◽  
Temporomandibular Joint ◽  
Real Time ◽  
Quality Analysis ◽  
Proton Density ◽  
High Temporal Resolution ◽  
Image Quality Analysis ◽  
Additional Information ◽  
Significant Difference ◽  
Friedman's Test

Objective: To test real-time MRI (rtMRI) using HASTE sequences in patients with suspected internal disk derangement (IDD) of temporomandibular joint (TMJ) and to compare these sequences with standard static sequences. Methods and materials: 99 TMJ were studied with both standard sequences (fat-saturated proton density) and HASTE sequences with high temporal resolution. Image quality was assessed using a 4-point Likert scale. Two radiologists analysed both standard and rtMRI sequences separately, randomly and blinded (by a third operator) to patients’ names in order to assess inter-observer repeatability. One of the radiologists performed the analysis twice for assessing intra-observer repeatability. The same radiologists evaluated randomly and blinded to the previous assessment both the sequences and decided in consensus which was the most credible. Qualitative scores were compared using Friedman’s test while concordance between radiologists and sequences was evaluated using the concordance correlation coefficient. Results: At image quality analysis, mean score was 3.41 for static MRI and 3.82 for rtMRI, with a statistically significant difference in favour of rtMRI (p < 0.0001). Inter-rater concordance between operator 1 (Op1) and operator 2 (Op2) with regard to the same sequence was high for both static and rtMRI sequences (0.824 and 0.888, respectively). Inter-rater variability of Op1 and Op2 between static and rtMRI sequences was lower (0.647 for Op1 and 0.633 for Op2). Among 71 discordances between sequences, 60 were judged in favour of rtMRI, while 11 were in favour of static MRI. Conclusion: rtMRI with HASTE sequences is a robust technique and provide additional information in assessing IDD compared to static sequences.

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