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Molin, Nils-Erik
Publications (10 of 74) Show all publications
Molin, N.-E. (2014). Optical Methods for Acoustics and Vibration Measurements (ed.). In: (Ed.), (Ed.), Springer Handbook of Acoustics: (pp. 1139-1163). Paper presented at . New York: Encyclopedia of Global Archaeology/Springer Verlag
Open this publication in new window or tab >>Optical Methods for Acoustics and Vibration Measurements
2014 (English)In: Springer Handbook of Acoustics, New York: Encyclopedia of Global Archaeology/Springer Verlag, 2014, p. 1139-1163Chapter in book (Refereed)
Abstract [en]

Modern optical methods applicable to vibration analysis, monitoring bending-wave propagation in plates and shells as well as propagating acoustic waves in transparent media such as air and water are described. Field methods, which capture the whole object field in one recording, and point measuring (scanning) methods, which measure at one point (small area) at a time (but in that point as a function of time), will be addressed. Temporally, harmonic vibrations, multi-frequency repetitive motions and transient or dynamic motions are included. Interferometric methods, such as time-average and real-time holographic interferometry, speckle interferometry methods such as television (TV) holography, pulsed TV holography and laser vibrometry, are addressed. Intensity methods such as speckle photography or speckle correlation methods and particle image velocimetry (PIV) will also be treated.

Place, publisher, year, edition, pages
New York: Encyclopedia of Global Archaeology/Springer Verlag, 2014
National Category
Applied Mechanics
Research subject
Experimental Mechanics
Identifiers
urn:nbn:se:ltu:diva-21056 (URN)10.1007/978-1-4939-0755-7_27 (DOI)ac3c060c-8895-42a2-8580-75c5a7c09f65 (Local ID)978-1-4939-0754-0 (ISBN)978-1-4939-0755-7 (ISBN)ac3c060c-8895-42a2-8580-75c5a7c09f65 (Archive number)ac3c060c-8895-42a2-8580-75c5a7c09f65 (OAI)
Note
Godkänd; 2014; 20150120 (andbra)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2017-11-24Bibliographically approved
Gren, P., Tatar, K., Granström, J., Molin, N.-E. & Jansson, E. (2006). Laser vibrometry measurements of vibration and sound fields of a bowed violin (ed.). Paper presented at . Measurement science and technology, 17(4), 635-644
Open this publication in new window or tab >>Laser vibrometry measurements of vibration and sound fields of a bowed violin
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2006 (English)In: Measurement science and technology, ISSN 0957-0233, E-ISSN 1361-6501, Vol. 17, no 4, p. 635-644Article in journal (Refereed) Published
Abstract [en]

Laser vibrometry measurements on a bowed violin are performed. A rotating disc apparatus, acting as a violin bow, is developed. It produces a continuous, long, repeatable, multi-frequency sound from the instrument that imitates the real bow-string interaction for a 'very long bow'. What mainly differs is that the back and forward motion of the real bow is replaced by the rotating motion with constant velocity of the disc and constant bowing force (bowing pressure). This procedure is repeatable. It is long lasting and allows laser vibrometry techniques to be used, which measure forced vibrations by bowing at all excited frequencies simultaneously. A chain of interacting parts of the played violin is studied: the string, the bridge and the plates as well as the emitted sound field. A description of the mechanics and the sound production of the bowed violin is given, i.e. the production chain from the bowed string to the produced tone

National Category
Applied Mechanics
Research subject
Experimental Mechanics
Identifiers
urn:nbn:se:ltu:diva-4368 (URN)10.1088/0957-0233/17/4/005 (DOI)000237497600007 ()2-s2.0-33645242120 (Scopus ID)24fdda20-6f73-11db-962b-000ea68e967b (Local ID)24fdda20-6f73-11db-962b-000ea68e967b (Archive number)24fdda20-6f73-11db-962b-000ea68e967b (OAI)
Note
Validerad; 2006; 20060925 (cira)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Molin, N.-E. & Zipser, L. (2004). Optical methods of today for visualizing sound fields in musical acoustics (ed.). Paper presented at . Acta Acoustica united with Acustica, 90(4), 618-628
Open this publication in new window or tab >>Optical methods of today for visualizing sound fields in musical acoustics
2004 (English)In: Acta Acoustica united with Acustica, ISSN 1610-1928, E-ISSN 1861-9959, Vol. 90, no 4, p. 618-628Article in journal (Refereed) Published
Abstract [en]

Pictures that demonstrate physical phenomena are important in science, so also in musical acoustics. In optics, interference, diffraction and polarization phenomena are for instance often pictured in text books. Phase contrast methods are used in microscopy to visualize transparent objects. Such methods have numerous applications in medicine and biology. Shadowgraph, schlieren and different kinds of classical interferometry setups are used in fluid mechanics to study laminar flow, turbulence, convection, subsonic and supersonic flow, shock waves etc. Propagating sound fields often accompany supersonic flow and shock waves. Also transparent object fields like sound and temperature fields can be pictured using optical measuring methods. Merits of these methods are that they are contactless, nondisturbing and wholefield methods. In this paper, some modern optical methods are presented that has the sensitivity and spatial resolution needed to visualize and measure sound fields in musical acoustics. They are computerized, all-electronic methods that present pictures but also give quantitative measures. Harmonic vibrations, standing waves, repetitive sequences and transient wave propagation will be addressed. TV holography, pulsed TV holography and scanning laser Doppler vibrometry (LDV), or scanning vibrometry will be discussed. Speckle photography and correlation methods like digital speckle photography (DSP) and particle image velocimetry (PIV) will also be shortly presented

National Category
Applied Mechanics
Research subject
Experimental Mechanics
Identifiers
urn:nbn:se:ltu:diva-6276 (URN)47d6c020-6f73-11db-962b-000ea68e967b (Local ID)47d6c020-6f73-11db-962b-000ea68e967b (Archive number)47d6c020-6f73-11db-962b-000ea68e967b (OAI)
Note
Validerad; 2004; 20060926 (cira)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2017-11-24Bibliographically approved
Molin, N.-E., Sjödahl, M., Gren, P. & Svanbro, A. (2004). Speckle photography combined with speckle interferometry (ed.). Paper presented at . Optics and lasers in engineering, 41(4), 673-686
Open this publication in new window or tab >>Speckle photography combined with speckle interferometry
2004 (English)In: Optics and lasers in engineering, ISSN 0143-8166, E-ISSN 1873-0302, Vol. 41, no 4, p. 673-686Article in journal (Refereed) Published
Abstract [en]

By combining speckle interferometry (SI) measurements with speckle photography, the fringe visibility can be kept high despite the presence of a large bulk or rotating motion of the object. This combined technique improves the usability and measuring range of both pulsed and phase-stepped Sl-methods. This paper reviews the theory of fringe formation in Sl and shows some recent applications of this combined technique

National Category
Applied Mechanics
Research subject
Experimental Mechanics
Identifiers
urn:nbn:se:ltu:diva-10173 (URN)10.1016/S0143-8166(02)00175-6 (DOI)000188925000007 ()2-s2.0-0347594746 (Scopus ID)8eecfe20-6f73-11db-962b-000ea68e967b (Local ID)8eecfe20-6f73-11db-962b-000ea68e967b (Archive number)8eecfe20-6f73-11db-962b-000ea68e967b (OAI)
Note
Validerad; 2004; 20060926 (cira)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Rossing, T. D., Molin, N.-E. & Runnemalm, A. (2003). Modal analysis of violin bodies viewed as three-dimensional structures (ed.). Journal of the Acoustical Society of America, 114(4), 2438
Open this publication in new window or tab >>Modal analysis of violin bodies viewed as three-dimensional structures
2003 (English)In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 114, no 4, p. 2438-Article in journal (Refereed) Published
Abstract [en]

Modal analyses of violins show several strong modes in the low frequency range. Holographic interferograms suggest that four strong modes can be interpreted as doublets having two and three nodal planes that intersect a cylinder with a roughly elliptical cross section at the bridge [A. Runnemalm, N.-E. Molin, and E. Jansson, J. Acoust. Soc. Am. 107, 3452-3459 (2000); M. Roberts and T. D. Rossing, Catgut Acoust. Soc. J. 3, 9-15 (1998)]. This is especially clear when the instrument is viewed simultaneously from three sides using mirrors, and the holographic system is made sensitive to in-plane motion as well. These doublets are not unlike those observed in cylindrical vibrators such as bells, and they remind us that a violin is a 3-dimensional object

National Category
Applied Mechanics
Research subject
Experimental Mechanics
Identifiers
urn:nbn:se:ltu:diva-8367 (URN)6e0f30a0-fed5-11db-b19d-000ea68e967b (Local ID)6e0f30a0-fed5-11db-b19d-000ea68e967b (Archive number)6e0f30a0-fed5-11db-b19d-000ea68e967b (OAI)
Note

Validerad; 2003; Bibliografisk uppgift: Presenterat på 146th meeting / Acoustical Society of America : Renaissance Austin Hotel, Austin, Texas, 10 - 14 November 2003.; 20070510 (cira)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-02-05Bibliographically approved
Zipser, L., Franke, H., Olsson, E., Molin, N.-E. & Sjödahl, M. (2003). Reconstructing two-dimensional acoustic object fields by use of digital phase conjugation of scanning laser vibrometry recordings (ed.). Paper presented at . Applied Optics, 42(29), 5831-5838
Open this publication in new window or tab >>Reconstructing two-dimensional acoustic object fields by use of digital phase conjugation of scanning laser vibrometry recordings
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2003 (English)In: Applied Optics, ISSN 1559-128X, E-ISSN 2155-3165, Vol. 42, no 29, p. 5831-5838Article in journal (Refereed) Published
Abstract [en]

scanning laser Doppler vibrometer is used to record two-dimensional ultrasound fields in air. The laser light of the vibrometer traverses the sound field to and from a rigid reflector and determines the velocity field, a quantity proportional to the sound pressure rate, in each scanned point relative to the sound source. The object sound is the scattered field from objects outside the recording area. Digital reconstruction by use of phase conjugation (time reversal) of the object sound field is then performed, and the original object field intensity and phase is reconstructed

National Category
Applied Mechanics
Research subject
Experimental Mechanics
Identifiers
urn:nbn:se:ltu:diva-8786 (URN)10.1364/AO.42.005831 (DOI)000185928000004 ()2-s2.0-0142149168 (Scopus ID)752a7300-6f73-11db-962b-000ea68e967b (Local ID)752a7300-6f73-11db-962b-000ea68e967b (Archive number)752a7300-6f73-11db-962b-000ea68e967b (OAI)
Note
Validerad; 2003; 20060926 (cira)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Olsson, E., Molin, N.-E., Sjödahl, M., Zipser, L. & Franke, H. (2003). Scattered ultrasound fields measured by scanning laser vibrometry (ed.). In: (Ed.), Wolfgang Osten (Ed.), Optical Measurement Systems for Industrial Inspection III: 23 - 26 June 2003, Munich, Germany. Paper presented at Optical Measurement Systems for Industrial Inspection : 23/06/2003 - 26/06/2003 (pp. 717-727). Bellingham, Wash.: SPIE - International Society for Optical Engineering
Open this publication in new window or tab >>Scattered ultrasound fields measured by scanning laser vibrometry
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2003 (English)In: Optical Measurement Systems for Industrial Inspection III: 23 - 26 June 2003, Munich, Germany / [ed] Wolfgang Osten, Bellingham, Wash.: SPIE - International Society for Optical Engineering, 2003, p. 717-727Conference paper, Published paper (Refereed)
Abstract [en]

A scanning laser Doppler vibrometer is used to make quantitative measurements of 2D ultrasound fields in air. The laser light traverses the measurement volume to and from a rigid reflector and determines the velocity of the change in optical path length, which with constant geometry only depends on the changes in index of refraction. Assuming adiabatic conditions, the refractive index rate is proportional to the sound pressure rate and quantitative measures of the sound field are possible to achieve. The emitted or scattered ultrasound being measured origins from a source or object outside the recording area. Using phase conjugation the sound field is then digitally reconstructed outside the recording area, and the reconstructed phase and intensity reveals the location of the source or object. The combination of several such reconstructions of ultrasound fields of different wavelengths, so called wavelength scanning, provides an intensity map that very accurately gives the position of the source. This opens many new possibilities to study hidden or unknown sound sources or scattering objects

Place, publisher, year, edition, pages
Bellingham, Wash.: SPIE - International Society for Optical Engineering, 2003
Series
Proceedings of SPIE, the International Society for Optical Engineering, ISSN 0277-786X ; 5144
National Category
Applied Mechanics
Research subject
Experimental Mechanics
Identifiers
urn:nbn:se:ltu:diva-31585 (URN)10.1117/12.500398 (DOI)000184287300081 ()2-s2.0-0141608622 (Scopus ID)5ce2b986-6480-4970-9648-d728a8855228 (Local ID)819450146 (ISBN)5ce2b986-6480-4970-9648-d728a8855228 (Archive number)5ce2b986-6480-4970-9648-d728a8855228 (OAI)
Conference
Optical Measurement Systems for Industrial Inspection : 23/06/2003 - 26/06/2003
Note
Validerad; 2003; 20120123 (ysko)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2018-07-10Bibliographically approved
Granqvist, S., Molin, N.-E., Sjödahl, M. & Hertegård, S. (2003). Speckle photography applied to detect structure displacement in high-speed laryngoscopic recordings (ed.). Paper presented at Pan European Voice Conference, PEVOC : 28/08/2003 - 31/08/2003. Paper presented at Pan European Voice Conference, PEVOC : 28/08/2003 - 31/08/2003.
Open this publication in new window or tab >>Speckle photography applied to detect structure displacement in high-speed laryngoscopic recordings
2003 (English)Conference paper, Oral presentation only (Refereed)
National Category
Applied Mechanics
Research subject
Experimental Mechanics
Identifiers
urn:nbn:se:ltu:diva-31137 (URN)536ff350-0205-11dc-ad0a-000ea68e967b (Local ID)536ff350-0205-11dc-ad0a-000ea68e967b (Archive number)536ff350-0205-11dc-ad0a-000ea68e967b (OAI)
Conference
Pan European Voice Conference, PEVOC : 28/08/2003 - 31/08/2003
Note
Godkänd; 2003; 20070514 (cira)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2017-11-25Bibliographically approved
Molin, N.-E. (2003). Visualization of sound fields with application to musical instruments (ed.). In: (Ed.), Roberto Bresin (Ed.), Proceedings of SMAC 03: Stockholm Music Acoustics Conference, August 6-9, 2003. Paper presented at Stockholm Music Acoustics Conference : 06/08/2003 - 09/08/2003. Stockholm: Kungl. Tekniska Högskolan
Open this publication in new window or tab >>Visualization of sound fields with application to musical instruments
2003 (English)In: Proceedings of SMAC 03: Stockholm Music Acoustics Conference, August 6-9, 2003 / [ed] Roberto Bresin, Stockholm: Kungl. Tekniska Högskolan , 2003Conference paper, Published paper (Refereed)
Abstract [en]

Modern optical measuring methods have the advantage of being contact less, non-disturbing and whole field methods. They often are quantitative and they present "pictures". In the following some modern optical, holographic, speckle and interferometric methods that visualize and measure vibrations and sound fields of musical instruments are presented and discussed

Place, publisher, year, edition, pages
Stockholm: Kungl. Tekniska Högskolan, 2003
National Category
Applied Mechanics
Research subject
Experimental Mechanics
Identifiers
urn:nbn:se:ltu:diva-37840 (URN)bfc3a320-bb57-11db-b560-000ea68e967b (Local ID)bfc3a320-bb57-11db-b560-000ea68e967b (Archive number)bfc3a320-bb57-11db-b560-000ea68e967b (OAI)
Conference
Stockholm Music Acoustics Conference : 06/08/2003 - 09/08/2003
Note
Godkänd; 2003; 20061026 (cira)Available from: 2016-10-03 Created: 2016-10-03 Last updated: 2017-11-25Bibliographically approved
Jansson, E. & Molin, N.-E. (2002). Fundamental violin acoustics related to quality (ed.). In: (Ed.), Proceedings of the 32nd International Acoustical Conference: European Acoustics Association (EAA) Symposium "Acoustics Banská Štiavnica 2002" ; September 10 - 12, 2002, Slovakia. Paper presented at International Acoustical Conference : 10/09/2002 - 12/09/2002. Zvolen: TU Zvolen
Open this publication in new window or tab >>Fundamental violin acoustics related to quality
2002 (English)In: Proceedings of the 32nd International Acoustical Conference: European Acoustics Association (EAA) Symposium "Acoustics Banská Štiavnica 2002" ; September 10 - 12, 2002, Slovakia, Zvolen: TU Zvolen , 2002Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Zvolen: TU Zvolen, 2002
National Category
Applied Mechanics
Research subject
Experimental Mechanics
Identifiers
urn:nbn:se:ltu:diva-35074 (URN)97529f80-fee2-11db-b19d-000ea68e967b (Local ID)8022811599 (ISBN)97529f80-fee2-11db-b19d-000ea68e967b (Archive number)97529f80-fee2-11db-b19d-000ea68e967b (OAI)
Conference
International Acoustical Conference : 10/09/2002 - 12/09/2002
Note

Godkänd; 2002; 20070510 (cira)

Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2017-11-25Bibliographically approved
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