A Canonical Scatterer for Transient ScatteringRange Calibration
نویسندگان
چکیده
We describe here a simple process for calibrating a transient scattering range. The process uses a paraboloidal scatterer to transform an axially incident plane wave into a spherical wave. Since the magnitude of the scattered field is known analytically, one can simply calibrate a measurement system. In order to calculate the scattered field, we use a stereographic projection that has previously been called the reflector transform. This technique provides three advantages over traditional calibration with a sphere. First, it is potentially more accurate, since the scattering characteristics of a paraboloid are independent of frequency. There is no need to convert the measured time domain data to the frequency domain in order to deconvolve the characteristics of the scattere~ the entire process takes place in the time domain. Second, this technique is simpler to implement. Finally, this technique is appropriate for certain anechoic chambers built of two-wire and four-wire transmission lines, where the incident field is not quite uniform.
منابع مشابه
Scatterer size estimation in pulse-echo ultrasound using focused sources: calibration measurements and phantom experiments.
In a companion paper [T. A. Bigelow and W. D. O'Brien Jr., J. Acoust. Soc. Am. 116, 578 (2004)], theory, supported by simulations, showed that accurate scatterer size estimates could be obtained using highly focused sources provided that the derived generalized attenuation-compensation function was used and the velocity potential field near the focus could be approximated as a three-dimensional...
متن کاملTransient Measurement Site Design in pipe networks using the Decision Table Method (DTM)
The accuracy of leak detection and calibration of pipe networks by means of the inverse transient analysis (ITA) is highly affected by the number and location of the measurement sites. This study introduces a conceptual decision-making model, the Decision Table Method (DTM), for the measurement site design of pipe networks with the aim of inverse transient analysis. Through the Decision Table M...
متن کاملSensitivity of quantitative photoacoustic tomography inversion schemes to experimental uncertainty
The ability to accurately quantify chromophore concentration from photoacoustic images would have a major impact on pre-clinical and clinical imaging. Recent years have seen significant advances in the theoretical understanding of quantitative photoacoustic imaging and in the development of model-based inversion strategies that overcome issues such as non-uniqueness and non-linearity. Neverthel...
متن کاملDetermining Transmission Eigenvalues of Anisotropic Inhomogeneous Media from Far Field Data
We characterize interior transmission eigenvalues of penetrable anisotropic acoustic scattering objects by a technique known as inside-outside duality. This method has recently been identified to be able to link interior eigenvalues of the penetrable scatterer with the behavior of the eigenvalues of the far field operator for the corresponding exterior time-harmonic scattering problem. A basic ...
متن کاملSample Extraction Bsaed on Helix Scattering for Polarimetric Sar Calibration
Polarimetric calibration (PolCAL) of Synthetic Aperture Radar (SAR) images is a significant preprocessing for further applications. Since the reflection symmetry property of distributed objects can provide stable constraints for PolCAL. It is reasonable to extract these reference samples before calibration. The helix scattering generally appears in complex urban area and disappears for a natura...
متن کامل