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  • Leutenegger, Tobias (2023): «Proof of Brain Gain». In: Wissensplatz, S. 14-15. Available online at https://www.fhgr.ch/fh-graubuenden/medien-und-oeffentlichkeit/publikationen/wissensplatz/februar-2023/, last checked on 18.02.2023

     

    Abstract: Landquart, Forum Ried, 22. September 2022: Die Photonics-Absolvierenden der Fachhochschule Graubünden erhalten vom Rektor und ihrem Studienleiter Tobias Leutenegger ihre wohlverdienten Bachelordiplome. Stolz halten eine Photonics-Ingenieurin und neun Photonics-Ingenieure die Urkunden in ihren Händen. Hurra, geschafft! Studium erfolgreich abgeschlossen – und jetzt?

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  • Leutenegger, Tobias (2022): Mission «Alpine Drone Rescue» oder «Rette mich!». In: Wissensplatz, S. 6-7. Available online at https://www.fhgr.ch/fhgr/medien-und-oeffentlichkeit/publikationen/wissensplatz/februar-2022/, last checked on 10.02.2022

     

    Abstract: Ein herrlicher Herbsttag im schönen Graubünden – der Himmel stahlblau, die Luft klar, aber schon etwas kühl, und das Ziel in Reichweite. Mit den Kolleginnen und Kollegen brechen wir auf zur nächsten Etappe. Wir fühlen uns fit und kommen gut voran. Der Schwierigkeitsgrad ist fordernd, aber wir sind ja auch keine Anfängerinnen und Anfänger mehr. Für einen kurzen Moment sind wir nicht konzentriert und alles geht sehr schnell: Ein Tritt ins Leere, der freie Fall, alles dreht sich und die potenzielle Energie wird in kinetische Energie umgewandelt. Wir warten auf den Aufprall und denken: Wars das?

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  • Leutenegger, Tobias (2020): Der Murmeltier-Wettkampf. In: Wissensplatz, S. 12-13. Available online at https://www.fhgr.ch/fhgr/medien-und-oeffentlichkeit/publikationen/wissensplatz/februar-2020/, last checked on 28.02.2020

     

    Abstract: Eine praxisorientierte Ausbildung ist einer der wichtigsten Aspekte für die erfolgreiche Vorbereitung der Studierenden des Bachelorstudiengangs Photonics auf die Arbeitswelt. Mit dem Projekt «Murmeltier», einer Art Kugelbahn, waren die Absolventinnen und Absolventen im letzten Jahr stark gefordert. Sie bewiesen ihrem Studienleiter jedoch, dass sie bereit sind für die Arbeitswelt.

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  • Birk, Udo; Andres, Michael; Kessler, Viktor; Linvers, Chris; Zbinden, David; Catregn, Gion-Pol; Leutenegger, Tobias (2018): Image Processing and Machine Vision for Engineering Undergraduate Students. 11th International Conference on Machine Vision ICMV. München, 2. November, 2018

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  • Merbold, Hannes; Catregn, Gion-Pol; Leutenegger, Tobias (2018): Optimizing time-of-flight cameras for underwater applications. Graubünden forscht. Academia Raetica. Davos, 19. September, 2018

    Abstract: In recent years, time-of-flight (ToF) cameras have emerged as a reliable and cost-effective way to provide high frame-rate range imaging. Today, this technology is used to address a wealth of applications including object detection, collision prevention, or gesture recognition. Here, we describe the implementation of the technology for underwater applications. The challenge arising from this adaptation is that the near-IR regime, in which current ToF sensors typically operate, is far from ideal for this application due to the strong absorption of liquid water. We show that by operating existing ToF imaging chips in combination with LED light sources at visible wavelengths, distance sensing with ranges on the meter level can be realized. We find that the attainable performance depends on a variety of parameters, such as the wavelength dependent absorption of water, the emitted optical power and response times of the LEDs, or the spectral sensitivity of the TOF chip. An in-depth analysis of the interplay between the different parameters is given and the performance of underwater TOF imaging using different visible illumination wavelengths is analyzed.

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  • Merbold, Hannes; Catregn, Gion-Pol; Leutenegger, Tobias (2018) : Time-of-flight range imaging for underwater applications In: Soskind, Yakov G.: Photonic Instrumentation Engineering V: Proceedings: SPIE Photonics West: San Francisco. SPIE The international society for optics and photonics (Proceedings of SPIE). Available online at https://doi.org/10.1117/12.2283476, last checked on 21.02.2020

     

    Abstract: Precise and low-cost range imaging in underwater settings with object distances on the meter level is demonstrated. This is addressed through silicon-based time-of-flight (TOF) cameras operated with light emitting diodes (LEDs) at visible, rather than near-IR wavelengths. We find that the attainable performance depends on a variety of parameters, such as the wavelength dependent absorption of water, the emitted optical power and response times of the LEDs, or the spectral sensitivity of the TOF chip. An in-depth analysis of the interplay between the different parameters is given and the performance of underwater TOF imaging using different visible illumination wavelengths is analyzed.

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  • Brauchli, R.; Leutenegger, Tobias (2017): Licht für intelligente Maschinen. In: Unternehmerzeitung 23, S. 14-15

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  • Leutenegger, Tobias (2017): Agile Arbeitswelten (Einblicke in die Forschung). Available online at https://www.fhgr.ch/fileadmin/publikationen/forschungsbericht/fhgr-Einblicke_in_die_Forschung_2017.pdf, last checked on 09.04.2021

     

    Abstract: Unternehmen können sich den immer rascher vollziehenden Veränderungen in Wirtschaft und Gesellschaft anpassen, wenn sie agile Arbeitswelten schaffen. Ein viel versprechender Ansatz besteht darin, den Mitarbeitenden unternehmerische Freiheit und Verantwortung zu übertragen.

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  • Leutenegger, Tobias (2017): Die Photonik ist im Aufwind. Ausbildungsbedarf und -situation. In: bulletin.ch 108, S. 35-36. Available online at https://www.bulletin.ch/de/news-detail/die-photonik-ist-im-aufwind.html, last checked on 21.02.2020

     

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  • Leutenegger, Tobias (2017): Licht hat Zukunft. In: Wissensplatz, S. 14-15. Available online at https://www.fhgr.ch/fhgr/medien-und-oeffentlichkeit/publikationen/wissensplatz/februar-2017/, last checked on 07.12.2018

     

    Abstract: Photonics ist eine der sechs key enabling technologies, welche die EU als zukunftsträchtigste Technologien definiert hat. Täglich sind wir mit Photonics konfrontiert. Die Wichtigkeit von Photonics nimmt auch in der Schweizer Wirtschaft stetig zu. Viele Schweizer Unternehmen sind mit ihren Photonics-Produkten weltweit führend. Das Wachstum der Branche führt zu einem steigenden Bedarf an Photonics-Ingenieurinnen und -Ingenieuren. Die HTW Chur bietet daher das schweizweit erste und einzigartige Bachelorstudium Photonics an.

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  • Leutenegger, Tobias (2017): Studium Photonics: Nahe an der Industrie. In: Photonik 49. Available online at https://www.photonik.de/studium-photonics-nahe-an-der-industrie/150/25109/350467, last checked on 21.02.2020

     

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  • Leutenegger, Tobias (2016): Photonics und Industrie 4.0. Neue Dimensionen in der Optoelektronik. Technologie Forum Zug. Cham, 24. August, 2016

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  • Leutenegger, Tobias; Hunnius, Y. von (2016) : Woher das Licht für die Wirtschaft von morgen kommt Greater Area Zurich . Zürich, 14. November

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  • Leutenegger, Tobias (2016) : Pho­to­nics prägt schon heute unseren Alltag . Blog (FHGR Blog) . Available online at https://blog.fhgr.ch/blog/photonics-praegt-schon-heute-unseren-alltag/ , last checked on 28.03.2021

     

    Abstract: Photonics befasst sich mit allen Bereichen, welche mit Licht und deren Anwendung zu tun haben. Vielen ist aber die Bedeutung von Photonics in unserem Alltag noch nicht bewusst.

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  • Leutenegger, Tobias; Schär, Armando; Semar, Wolfgang; Studer, Martin (2016) : In­for­ma­tik­ta­ge 2016 . In­for­ma­tik von Morgen! . Blog (FHGR Blog) . Available online at https://blog.fhgr.ch/blog/informatiktage-2016-informatik-von-morgen/ , last checked on 28.03.2021

     

    Abstract: Was haben die drei Gebiete «Big Data», «3D-Bildverarbeitung» und «Digitale Geschäftsmodelle» gemeinsam? Sie alle werden durch innovative Technologien ermöglicht. Sie alle befinden sich in einer starken Wachstumsphase. Sie alle sind Teil von Industrie 4.0 und sie alle benötigen als Basis ausgezeichnete Informatik – die Informatik von Morgen! Im Rahmen der Informatiktage 2016 hat die HTW Chur am 3. Juni 2016 eine Informationsveranstaltung zum Thema «Informatik von Morgen!» durchgeführt.

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  • Leutenegger, Tobias (2016) : Wieso haben Gum­mi­bär­chen ver­schie­de­ne Farben? . Blog (FHGR Blog) . Available online at https://blog.fhgr.ch/blog/wieso-haben-gummibaerchen-verschiedene-farben/ , last checked on 19.03.2021

     

    Abstract: Die vielen «Helferlein», die uns rund um die Uhr begleiten, würden ohne modernste Technologien nicht mehr funktionieren. Oft spielt dabei die gezielte Verwendung von Licht eine wesentliche Rolle.

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  • Leutenegger, Tobias; Studer, Bruno (2015) : First Swiss bachelor in Photonics In: Cormier, Eric; Sarger, Laurent (Hg.): Education and Training in Optics and Photonics: Proceedings: ETOP: Bordeaux, 25. Juni - 2. Juli. SPIE The international society for optics and photonics (Proceedings of SPIE). Available online at https://doi.org/10.1117/12.2223216, last checked on 28.02.2020

     

    Abstract: Swissmem, the Swiss association of mechanical and electrical engineering industries, founded a new photonics group in 2013. This reflects the importance of this key technology for Switzerland. Swissmem requested from the Swiss Universities of Applied Sciences to introduce a new bachelor program to fulfill the increasing demand of the Swiss industry of young academics in the field of photonics. Optech Consulting is investigating the Swiss photonics market since many years on behalf of Swissphotonics, the Swiss national thematic network for photonics. The study concluded that the total production volume of the Swiss photonics industry in the year 2013 was 3 billion Swiss francs and a slight growth is expected for 2014. The University of Applied Science HTW Chur is located in the Eastern part of Switzerland. This area of the Rhine valley is a technology cluster of innovative companies in the field of optics and electronics. The industry is growing and the R&D departments of the worldwide active companies are lacking well-educated photonics engineers. The HTW Chur is dedicated to establish the first Swiss bachelor in Photonics. Supported by strong industrial players and an excellent network, the HTW Chur developed different job descriptions and a complete curriculum, which reflect the needs of the Swiss photonics industry. Almost 60% of the ECTS of this national degree program are assigned to photonics specific courses and the practical projects are organized in close collaboration with the photonics industry. Curriculum, job descriptions and the industrial needs will be discussed in detail in this paper.

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  • Gsell, Daniel; Leutenegger, Tobias; Dual, Jürg (2004): Modeling three-dimensional elastic wave propagation in circular cylindrical structures using a finite-difference approach. In: The Journal of the Acoustical Society of America 116. DOI: 10.1121/1.1625934

    Abstract: Wave propagation along circular cylindrical structures is important for nondestructive-testing applications and shocks in tubes. To simulate elastic wave propagation phenomena in such structures the governing equations in cylindrical coordinates are solved numerically. To reduce the required amount of computer memory and the computational time, the stress components are eliminated in the equilibrium equations. In the resulting coupled partial differential equations, in which only the three displacement components are involved, the derivatives with respect to spatial coordinates and time are approximated using second order central differences. This leads to the present new approach, which is both accurate and efficient. In order to obtain a stable scheme the displacements must be allocated on a staggered grid. The von Neumann stability analysis is performed and the result is compared with an existing empirical criterion. Mechanical energies are observed in order to validate the finite-difference code. Since no material damping or energy dissipation is taken into account in the equations of motion, the total energy must remain constant over time. Only negligible variations are observed during long-term simulations. Dispersion relations are used to check the physical behavior of the waves calculated with the proposed finite-difference method: Theoretically calculated curves are compared with values obtained by a spectrum estimation method, applied to the results of a simulation.

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  • Leutenegger, Tobias; Dual, Jürg (2004): Non-destructive testing of tubes using a time reverse numerical simulation (TRNS) method. In: Ultrasonics 41, S. 811-822. Available online at https://doi.org/10.1016/j.ultras.2003.12.046, last checked on 13.03.2023

     

    Abstract: A method for the detection of defects in cylindrical structures and the determination of their positions and orientations is presented in this paper. The scattered field, which is generated by the interaction of excited guided waves with a defect, is evaluated with an approach named time reverse numerical simulation method (TRNS). Since the excited waves and the scattered field propagate along the sample, the time-consuming scanning of the whole tube can be eliminated. The scattered displacement field is measured in three dimensions over time with a laser vibrometer at different locations distributed equally around the circumference at a fixed axial coordinate far away from the defect. Instead of analyzing the complicated time signals directly, they are played back in time. If the recorded displacement histories of the scattered field are reversed in time and played back in an identical structure, the waves travel back the same path and interfere to a maximum at their origin. The result is an amplitude increase at the position of the defect where the scattered field was generated. Instead of playing back the recorded time signals in an experiment, this step is replaced by a numerical simulation. Only this enables the visualization and detection of the amplitude increase. As long as the simulation is of high accuracy, the position of the maximum interference corresponds exactly to the location of the defect in the experiment, although no defect is implemented in the simulation.

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  • Leutenegger, Tobias; Dual, Jürg (2002): Detection of defects in cylindrical structures using a time reverse method and a finite-difference approach. In: Ultrasonics 40, S. 721-725. Available online at https://doi.org/10.1016/s0041-624x(02)00200-7, last checked on 13.03.2023

     

    Abstract: The detection and characterization of defects in structures is an important issue in non-destructive testing. To avoid the scanning of large samples, guided elastic waves, which propagate along the structure, are excited. These waves interact with a defect, which results in a scattered wave field. In an experiment, the displacements of these scattered waves are recorded over time for a fixed axial coordinate at a number of circumferential positions of a circular cylindrical tube. Since in complex structures it is difficult to determine the axial and particularly circumferential position of the defect directly from the time signals, a time reversed numerical simulation is performed. There the measured displacement histories are reversed in time and used as displacement excitations in a simulation of the tested structure. A three-dimensional code in cylindrical coordinates, based on a velocity-stress finite-difference method, is used to simulate the wave propagation. As long as the geometric and material parameters are chosen equivalent to the performed experiment, the scattered waves travel back through the simulated structure and interfere, even if no defect is present in the numerical model. The result is an increase of the amplitudes of the stress and displacement components at the location where the defect was in the tested sample.

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  • Leutenegger, Tobias; Schlums, Dirk H.; Dual, Jürg (1999) : Structural testing of fatigued structures In: Wereley, Norman M.: Smart Structures and Materials 1999: Smart Structures and Integrated Systems: 1999 Symposium on Smart Structures and Materials: Newport Beach, 1. März (SPIE Proceedings), S. 987-997

    DOI: http://proceedings.spiedigitallibrary.org/proceeding.aspx?articleid=982238 

    Abstract: The structural responses of beams and tubes is investigated in theory and experiment in order to locate and assess damage in the form of fatigue cracks. Crack length measurements are performed in transversely vibrating beams by determining the resonant frequency, which is stabilized through a phase locked loop. Cracks are initiated and propagate from the notch of the structure which is vibrating at resonance. The frequency in relation to the crack length is modeled including the nonlinearity effect due to closing of the crack. Fatigue tests were also carried out with piezoelectrically excited microstructures.

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