Publication detail

Calibration of an Ultrasonic Computed Tomography System

FILIPÍK, A. JAN, J. PETERLÍK, I. HEMZAL, D. JIŘÍK, R.

Original Title

Calibration of an Ultrasonic Computed Tomography System

English Title

Calibration of an Ultrasonic Computed Tomography System

Type

conference paper

Language

en

Original Abstract

A 3D setup for USCT has been developed at Forschungszentrum Karlsruhe (FZK), Germany [1]. The system (Figure 1) consists of 384 senders and 1536 receivers mounted on 48 transducer array systems (TAS). For the reconstruction of tomographic images, it is crucial to know the positions of individual transducers within error in the order of the wavelength magnitude; even small positioning errors (in the range of tenths of millimeters) can lead to significant degradation of image quality. With respect to the number of transducers in the system, it is unfeasible to measure the geometry manually. An auto-calibration technique, which utilizes only the internal ultrasonic signals used by the system to solve the problem, has been designed and tested. The technique is based on time-of-flight principle, similar to GPS navigation. Particularly, the time-of-flights of individual ultrasonic pulses are used for a triangulation, formulated as a minimization problem, where the to-be-minimized quantity is the sum of squares of differences between measured and estimated pulse arrival times. The to-be-determined minimization parameters are the positions and the individual time-delays of transducers. Also, the calibration of the directivity characteristics and individual efficiencies of the trasnducers has been described.

English abstract

A 3D setup for USCT has been developed at Forschungszentrum Karlsruhe (FZK), Germany [1]. The system (Figure 1) consists of 384 senders and 1536 receivers mounted on 48 transducer array systems (TAS). For the reconstruction of tomographic images, it is crucial to know the positions of individual transducers within error in the order of the wavelength magnitude; even small positioning errors (in the range of tenths of millimeters) can lead to significant degradation of image quality. With respect to the number of transducers in the system, it is unfeasible to measure the geometry manually. An auto-calibration technique, which utilizes only the internal ultrasonic signals used by the system to solve the problem, has been designed and tested. The technique is based on time-of-flight principle, similar to GPS navigation. Particularly, the time-of-flights of individual ultrasonic pulses are used for a triangulation, formulated as a minimization problem, where the to-be-minimized quantity is the sum of squares of differences between measured and estimated pulse arrival times. The to-be-determined minimization parameters are the positions and the individual time-delays of transducers. Also, the calibration of the directivity characteristics and individual efficiencies of the trasnducers has been described.

Keywords

ultrasound, ultrasonic computed tomography, USCT, calibration

RIV year

2007

Released

09.12.2007

Publisher

ÚTIA AVČR

Location

Praha

Pages from

16

Pages to

16

Pages count

1

BibTex


@inproceedings{BUT25634,
  author="Adam {Filipík} and Jiří {Jan} and Igor {Peterlík} and Dušan {Hemzal} and Radovan {Jiřík}",
  title="Calibration of an Ultrasonic Computed Tomography System",
  annote="A 3D setup for USCT has been developed at Forschungszentrum Karlsruhe (FZK), Germany [1]. The system (Figure 1) consists of 384 senders and 1536 receivers mounted on 48 transducer array systems (TAS). For the reconstruction of tomographic images, it is crucial to know the positions of individual transducers within error in the order of the wavelength magnitude; even small positioning errors (in the range of tenths of millimeters) can lead to significant degradation of image quality. With respect to the number of transducers in the system, it is unfeasible to measure the geometry manually. An auto-calibration technique, which utilizes only the internal ultrasonic signals used by the system to solve the problem, has been designed and tested. The technique is based on time-of-flight principle, similar to GPS navigation. Particularly, the time-of-flights of individual ultrasonic pulses are used for a triangulation, formulated as a minimization problem, where the to-be-minimized quantity is the sum of squares of differences between measured and estimated pulse arrival times. The to-be-determined minimization parameters are the positions and the individual time-delays of transducers. Also, the calibration of the directivity characteristics and individual efficiencies of the trasnducers has been described. 
",
  address="ÚTIA AVČR",
  booktitle="Abstracts of Contributions to 3rd International Workshop on Data-Algorithms-Decision Making, Liblice 2007",
  chapter="25634",
  edition="UTIA AVČR",
  institution="ÚTIA AVČR",
  year="2007",
  month="december",
  pages="16--16",
  publisher="ÚTIA AVČR",
  type="conference paper"
}