Investigation of the near field of a loudspeaker using tomographic reconstruction from TV-holography measurements

Rustad, Rolf; Morset, Lars Henrik

doi:10.1121/1.424362

Cited by 12 publications

(13 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Instantaneous three-dimensional density and ultimately pressure are calculated from this function. The full relationship between the measured refractive index perturbation and the mass density variation induced by the ultrasonic field is given in Section II-A by (1).…”

Section: Discussionmentioning

confidence: 99%

“…A tremendous amount of effort has been spent on the development of optical measurement methods for obtaining various parameters of ultrasound fields in transparent materials [1]- [11]. The research stretches from the first accurate model of the physics involved in optical scattering by a narrow band ultrasound field by Raman and Nath [12]- [16] in the early 1900s to very recent research by a number of investigators.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Optical phase contrast measurement of ultrasonic fields

Pitts¹,

Sagers

2001

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

View full text Add to dashboard Cite

This report describes an optical phase contrast imaging technique for the measurement of wide bandwidth ultrasound fields in water. In this method, a collimated optical wavefront ( l = 810 nm) impinges on a wide bandwidth ultrasound pulse. The method requires that refractive index perturbations induced by the ultrasound field be sufficiently small. Specifically, on exit from the acoustic field, the phase of the optical wavefront must be proportional to the ray sum of local density taken in the direction of propagation of the incident optical wave. A similar restriction is placed on the dimensions of the ultrasound pulse. Repeated measurement of this phase as the ultrasound field is rotated through 180 about an axis normal to the direction of propagation of the incident optical wave generates the Radon transform of the ultrasonically induced refractive index perturbation. Standard tomographic reconstruction techniques are used to reconstruct the full three-dimensional refractive index perturbation. A simple two-lens imaging system and an optical signal processing element from phase contrast microscopy provide a method of directly measuring an affine function of the desired optical phase for small optical phase shifts. The piezo-and elasto-optic coefficients (the first partial derivatives of refractive index with respect to density and pressure) relate refractive index to density and pressure via a linear model. The optical measurement method described in this paper provides a direct, quantitative measurement of the piezoand elasto-optic coefficients (from the density or pressure fields).

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Optical phase contrast measurement of ultrasonic fields

Pitts¹,

Sagers

2001

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

View full text Add to dashboard Cite

show abstract

“…This method of obtaining the optical phase delay is applicable over a broader range of field intensities and dimensions than are described in Section II-C. 1 [20], [21], [29], [32]. Higher intensity fields will cause the breakdown of the simple optical phase delay model for the acousto-optic interaction described in (8).…”

Section: Phase Contrast Methodmentioning

confidence: 98%

“…Greenleaf is with Ultrasound Research Laboratory, Mayo Clinic and Foundation, Rochester, MN 55901. 1 Here and elsewhere in the text the term scattering refers to redirection of electromagnetic energy by material inhomogeneities. the optical beam path to obtain useful measurements.…”

Section: Introductionmentioning

confidence: 99%

“…S cientists and engineers have spent much effort on the development and investigation of optical measurement techniques for estimating various parameters of ultrasonic fields in optically transparent materials [1]- [11]. After a number of attempts by prominent contemporary scientists, Raman and Nath presented the first accurate model of the physics involved in optical scattering 1 by a narrowband ultrasound field in a series of papers published in 1935 and 1936 [12]- [16].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Optical measurement of ultrasonic Poynting and velocity vector fields

Pitts

2002

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

View full text Add to dashboard Cite

This report describes a method for estimating several wide bandwidth ultrasonic field parameters from optical measurements of the local, acoustically induced, refractive index perturbation in water. These parameters include Poynting and particle velocity vector fields as well as pressure and density fields at any temporal delay under mild (forward-propagating) assumptions on the angular plane-wave spectrum of the ultrasound field. A sampling theorem is derived stating that two complete measurements of the three-dimensional pressure field separated in time by ∆t allow release of the forward-propagating assumption for every acoustic wave number k satisfying k 6 = n =(c∆t), where c is the acoustic wave speed in the medium and n an integer greater than zero. The approach provides detailed measurements of very general ultrasound fields.Two optical measurement methods that acquire the Radon transform of the three-dimensional refractive index perturbation are briefly reviewed. It is shown that the Radon transform of the field itself satisfies a twodimensional wave equation and may be propagated independently forward or backward in time under a source-free model. Conversely, the Radon transform of the ultrasound field measurement at several known time delays provides a means of applying a filter to the data based on known ultrasound propagation models. Each two-dimensional distribution may be propagated to a common time point and the ensemble averaged, thus incorporating the propagation model into the measurement. We support the presented theory with several experiments.

show abstract

Sound field monitoring by tomographic electronic speckle pattern interferometry

Joost

Hinsch

2006

Optics Communications

View full text Add to dashboard Cite

Investigation of the near field of a loudspeaker using tomographic reconstruction from TV-holography measurements

Cited by 12 publications

References 7 publications

Optical phase contrast measurement of ultrasonic fields

Optical phase contrast measurement of ultrasonic fields

Optical measurement of ultrasonic Poynting and velocity vector fields

Sound field monitoring by tomographic electronic speckle pattern interferometry

Contact Info

Product

Resources

About