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Acoustic Tomography

The Experts below are selected from a list of 4290 Experts worldwide ranked by ideXlab platform

Han Lan Ke – 1st expert on this subject based on the ideXlab platform

  • Study on the Photosynthetic Efficiency of the Osmanthus fragrans Leaves by Using Photo-Acoustic Tomography Spectroscopy Technology
    Advanced Materials Research, 2020
    Co-Authors: Han Lan Ke

    Abstract:

    By using a new kind of single-beam normalized photo-Acoustic Tomography spectroscopy (PAS-CT) technology with non-damage detection, the photo-Acoustic Tomography spectroscopy, optical absorption properties and photosynthetic pigment content of the green and yellow leaves of Osmanthus fragrans were studied. The results show that: photo-Acoustic Tomography spectroscopy could be obtained from different chopping frequency and different sample position. The more photosynthetic pigment content the leaves of Osmanthus fragrans contains, the bigger optical absorption coefficient and the higher photosynthetic efficiency they have. In the research, we could find that the photosynthetic pigment content of the green leaves of Osmanthus fragrans is higher than that of the yellow ones. As a result, the optical absorption coefficient and the photosynthetic efficiency of the green ones are higher than the yellow ones. The photo-Acoustic Tomography spectroscopy technology could be a kind of non-damage detection to confirm the growth of trees.

  • Study on the Photosynthetic Efficiency of the Cinnamomum camphora Leaves by Using Photo-Acoustic Tomography Spectroscopy Technology
    Advanced Materials Research, 2012
    Co-Authors: Han Lan Ke, Ting Yang, Dong Yu Li, Dao Qing Zhang, Xiao Qiong Feng

    Abstract:

    By using a new kind of single-beam normalized photo-Acoustic Tomography spectroscopy (PAS-CT) technology with non-damage detection, the photo-Acoustic Tomography spectroscopy, optical absorption properties and photosynthetic pigment content of the green and yellow leaves of Cinnamomum camphora were studied. The results show that: photo-Acoustic Tomography spectroscopy could be obtained from different chopping frequency and different sample position. The more photosynthetic pigment content the leaves of Cinnamomum camphora contains, the bigger optical absorption coefficient and the higher photosynthetic efficiency they have. In the research, we could find that the photosynthetic pigment content of the green leaves of Cinnamomum camphora is higher than that of the red ones. As a result, the optical absorption coefficient and the photosynthetic efficiency of the green ones are higher than the red ones. The photo-Acoustic Tomography spectroscopy technology could be a kind of non-damage detection to confirm the growth of trees.

  • Study on the Photosynthetic Efficiency of the Michelia alba Leaves by Using Photo-Acoustic Tomography Spectroscopy Technology
    Advanced Materials Research, 2012
    Co-Authors: Xiao Qiong Feng, Ting Yang, Dao Qing Zhang, Han Lan Ke

    Abstract:

    By using a new kind of single-beam normalized photo-Acoustic Tomography spectroscopy (PAS-CT) technology with non-damage detection, the photo-Acoustic Tomography spectroscopy, optical absorption properties and photosynthetic pigment content of the green and yellow leaves of Michelia alba were studied. The results show that: photo-Acoustic Tomography spectroscopy could be obtained from different chopping frequency and different sample position. The more photosynthetic pigment content the leaves of Michelia alba contains, the bigger optical absorption coefficient and the higher photosynthetic efficiency they have. In the research, we could find that the photosynthetic pigment content of the green leaves of Michelia alba is higher than that of the yellow ones. As a result, the optical absorption coefficient and the photosynthetic efficiency of the green ones are higher than the yellow ones. The photo-Acoustic Tomography spectroscopy technology could be a kind of non-damage detection to confirm the growth of trees.

Astrid Ziemann – 2nd expert on this subject based on the ideXlab platform

  • Acoustic Tomography of the Atmosphere Using Unscented Kalman Filter
    IEEE Transactions on Geoscience and Remote Sensing, 2014
    Co-Authors: Soheil Kolouri, Mahmood R. Azimi-sadjadi, Astrid Ziemann

    Abstract:

    Acoustic travel-time Tomography of the atmosphere is a nonlinear inverse problem which attempts to reconstruct temperature and wind velocity fields in the atmospheric surface layer using the dependence of sound speed on temperature and wind velocity fields along the propagation path. This paper presents a new statistical-based Acoustic travel-time Tomography algorithm based on unscented Kalman filter (UKF) which is capable of reconstructing and tracking temperature and wind velocity fields (state variables) within a specified investigation area. The method exploits an iterative ray-tracing algorithm to handle situations when straight-ray assumption no longer holds. The observations used in the UKF process consists of the Acoustic travel times computed for every pair of transmitter/reciever nodes deployed in the investigation area. A first-order spatial-temporal autoregressive model is used to account for state evolution in the UKF. To evaluate the performance of the UKF-based Acoustic Tomography method, 2-D fractal Brownian motion is used to generate synthetic temperature and wind velocity fields with spatial and temporal resolution of 1 m and 12 s, respectively. The UKF-based Acoustic Tomography algorithm is then compared to the well-known time-dependent stochastic inversion method. The results reveal the effectiveness of the proposed method for accurate and fast reconstruction of temperature and wind velocity fields.

  • recent progress in Acoustic Tomography of the atmosphere
    IOP Conference Series: Earth and Environmental Science, 2008
    Co-Authors: D.k. Wilson, Vladimir E. Ostashev, Sergey N Vecherin, Astrid Ziemann, George H Goedecke

    Abstract:

    Acoustic Tomography of the atmospheric surface layer is based on measurements of travel times of sound propagation among different pairs of sources and receivers usually located several meters above the ground on a horizontal scale of about 100 m. The measured travel times are used as input data in an inverse algorithm for reconstruction of temperature and wind velocity fields. Improved knowledge of these fields is important in boundary layer meteorology, theories of turbulence, and studies of electromagnetic and Acoustic wave propagation in the atmosphere. In this paper, a short overview and current status of Acoustic travel-time Tomography of the atmosphere are presented. A brief description of a 3D array for Acoustic Tomography of the atmosphere which is being built at the Boulder Atmospheric Observatory is given. Furthermore, different inverse algorithms for reconstruction of temperature and velocity fields are discussed, including stochastic inversion and a recently developed time-dependent stochastic inversion. The latter inverse algorithm was used to reconstruct temperature and wind velocity fields in Acoustic Tomography experiments. Examples of the reconstructed fields are presented and discussed.

  • Acoustic Tomography inside the atmospheric boundary layer
    Physics and Chemistry of The Earth Part B-hydrology Oceans and Atmosphere, 1999
    Co-Authors: Klaus Arnold, Astrid Ziemann, Armin Raabe

    Abstract:

    Abstract Acoustic Tomography is presented as a technique for remote monitoring of meteorological quantities. This method and a special algorithm of analysis can directly produce area averaged values of meteorological parameters. As a result, consistent data will be delivered for validation of numerical atmospheric micro-scale models. Such a measuring system can complement conventional point measurements over different surfaces. The procedure of Acoustic Tomography uses the horizontal propagation of sound waves in the atmospheric surface layer. The state of the crossed atmosphere can be estimated from measurements of travel time of Acoustic signals between sources and receivers on different points in a tomographic array. Derivation of area averaged values of the sound speed and furthermore of air temperature results from the inversion of travel time values for all possible Acoustic paths. Thereby, the applied straight-ray two-dimensional Tomography model is characterised as a method with small computational equirements and simple handling, especially, for online work.

Xiao Qiong Feng – 3rd expert on this subject based on the ideXlab platform

  • Study on the Photosynthetic Efficiency of the Cinnamomum camphora Leaves by Using Photo-Acoustic Tomography Spectroscopy Technology
    Advanced Materials Research, 2012
    Co-Authors: Han Lan Ke, Ting Yang, Dong Yu Li, Dao Qing Zhang, Xiao Qiong Feng

    Abstract:

    By using a new kind of single-beam normalized photo-Acoustic Tomography spectroscopy (PAS-CT) technology with non-damage detection, the photo-Acoustic Tomography spectroscopy, optical absorption properties and photosynthetic pigment content of the green and yellow leaves of Cinnamomum camphora were studied. The results show that: photo-Acoustic Tomography spectroscopy could be obtained from different chopping frequency and different sample position. The more photosynthetic pigment content the leaves of Cinnamomum camphora contains, the bigger optical absorption coefficient and the higher photosynthetic efficiency they have. In the research, we could find that the photosynthetic pigment content of the green leaves of Cinnamomum camphora is higher than that of the red ones. As a result, the optical absorption coefficient and the photosynthetic efficiency of the green ones are higher than the red ones. The photo-Acoustic Tomography spectroscopy technology could be a kind of non-damage detection to confirm the growth of trees.

  • Study on the Photosynthetic Efficiency of the Michelia alba Leaves by Using Photo-Acoustic Tomography Spectroscopy Technology
    Advanced Materials Research, 2012
    Co-Authors: Xiao Qiong Feng, Ting Yang, Dao Qing Zhang, Han Lan Ke

    Abstract:

    By using a new kind of single-beam normalized photo-Acoustic Tomography spectroscopy (PAS-CT) technology with non-damage detection, the photo-Acoustic Tomography spectroscopy, optical absorption properties and photosynthetic pigment content of the green and yellow leaves of Michelia alba were studied. The results show that: photo-Acoustic Tomography spectroscopy could be obtained from different chopping frequency and different sample position. The more photosynthetic pigment content the leaves of Michelia alba contains, the bigger optical absorption coefficient and the higher photosynthetic efficiency they have. In the research, we could find that the photosynthetic pigment content of the green leaves of Michelia alba is higher than that of the yellow ones. As a result, the optical absorption coefficient and the photosynthetic efficiency of the green ones are higher than the yellow ones. The photo-Acoustic Tomography spectroscopy technology could be a kind of non-damage detection to confirm the growth of trees.