scholarly journals Ambiguity Analysis and Resolution for Phase-Based 3D Source Localization under Given UCA

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Zhen Liu ◽  
Xin Chen ◽  
Zhenhua Wei ◽  
Tianpeng Liu ◽  
Linlin Li ◽  
...  
Keyword(s):  
Ambiguity Resolution ◽  
Elevation Angle ◽  
Three Dimensional ◽  
Estimation Algorithm ◽  
Cosine Function ◽  
Phase Ambiguity ◽  
Key Factors ◽  
Half Wavelength ◽  
Parameter Estimation Algorithm ◽  
Resolution Algorithm

Under uniform circular array, by employing some algebraic schemes to exploit the phase information of receiving data and further estimate the source’s three-dimensional (3D) parameters (azimuth angle, elevation angle, and range), a series of novel phase-based algorithms with low computational complexity have been proposed recently. However, when the array diameter is larger than source’s half-wavelength, these algorithms would suffer from phase ambiguity problem. Even so, there always exist certain positions, where the source’s parameters can still be determined with nonambiguity. Therefore, this paper first investigates the zone of ambiguity-free source 3D localization using phase-based algorithms. For the ambiguous zone, a novel ambiguity resolution algorithm named ambiguity traversing and cosine matching (ATCM) is presented. In ATCM, the phase differences of centrosymmetric sensors under different ambiguities are utilized to match a cosine function with sensor number-varying, and the source’s unambiguous rough angles can be derived from amplitude and initial phase of the cosine function. Then, the unambiguous angles are employed to resolve the phase ambiguity of the phase-based 3D parameter estimation algorithm, and the source’s range as well as more precise angles can be achieved. Theoretical analyses and numerical examples show that, apart from array diameter and source’s frequency, the sensor number and spacing of employed sensors are two key factors determining the unambiguous zone. Moreover, simulation results demonstrate the effectiveness and satisfactory performance of our proposed ambiguity resolution algorithm.

scholarly journals Research on Ambiguity Resolution Algorithm by Quaternion Based on Acoustic Vector Sensor

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Guibao Wang ◽  
Xinkuan Wang ◽  
Lanmei Wang ◽  
Xiangyu Wang
Keyword(s):  
Ambiguity Resolution ◽  
Sensor Array ◽  
Doa Estimation ◽  
Acoustic Velocity ◽  
Phase Ambiguity ◽  
Acoustic Vector Sensor ◽  
Vector Sensor ◽  
Half Wavelength ◽  
Simulation Results ◽  
Resolution Algorithm

The increase in element spacing can increase the aperture of the array and improve its resolution performance. However, phase ambiguity will occur when the array element interval is larger than the minimum half wavelength of the incident signal. The three acoustic velocity components of the acoustic vector are ingeniously constructed into a new kind of quaternions because of the special structure of the acoustic vector sensor array, and the rough estimation of the direction of arrival (DOA) is obtained using the rotation relationship between the subarray steering vectors corresponding to quaternion data. The rough estimate is used to resolve the phase ambiguity of the spatial phase difference between the array elements, and the high-precision DOA estimation of the signal can be obtained. Simulation results show that the method is effective.

scholarly journals Ambiguity Resolution for Passive 2-D Source Localization with a Uniform Circular Array

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2650 ◽  
Author(s):  
Jinlong Xin ◽  
Guisheng Liao ◽  
Zhiwei Yang ◽  
Haoming Shen
Keyword(s):  
Ambiguity Resolution ◽  
Relative Phase ◽  
Elevation Angle ◽  
Estimation Accuracy ◽  
Observation Model ◽  
Circular Array ◽  
Phase Ambiguity ◽  
Two Phase ◽  
Phase Observation ◽  
Phase Differences

This paper proposes two novel phase-based algorithms for the passive localization of a single source with a uniform circular array (UCA) under the case of measuring phase ambiguity based on two phase difference observation models, which are defined as the unambiguous-relative phase observation model (UARPOM) and the ambiguous-relative phase observation model (ARPOM). First, by analyzing the varying regularity of the phase differences between the adjacent array elements of a UCA, the corresponding relationship between the phase differences and the azimuth and elevation angle of the signal is derived. Based on the two phase observation models, two corresponding novel algorithms, namely, the phase integral accumulation and the randomized Hough transform (RHT), are addressed to resolve the phase ambiguity. Then, by using the unambiguous phase differences, the closed-form estimates of the azimuth and elevation angles are determined via a least squares (LS) algorithm. Compared with the existing phase-based methods, the proposed algorithms improve the estimation accuracy. Furthermore, our proposed algorithms are more flexible for the selection of an array radius. Such an advantage could be applied more broadly in practice than the previous methods of ambiguity resolution. Simulation results are presented to verify the effectiveness of the proposed algorithm.

Simultaneous Measurement of the Orthogonal Components of Thermal Diffusivity in PVC Sheet

1999 ◽  
Vol 122 (1) ◽  
pp. 27-32 ◽  
Author(s):  
D. J. Doss ◽  
N. T. Wright
Keyword(s):  
Thermal Diffusivity ◽  
Three Dimensional ◽  
Estimation Algorithm ◽  
Flash Method ◽  
Plane Component ◽  
Out Of Plane ◽  
Parameter Estimation Algorithm ◽  
Orthogonal Components ◽  
Bottom Face ◽  
Made In

An extension of the flash method is described that measures simultaneously the three orthogonal components of thermal diffusivity in specimens of moderate thermal diffusivity. Only part of the top face of the specimen is illuminated and the temperature histories are recorded at three points on the bottom face. A Marquardt parameter estimation algorithm coupled with a finite difference model of the diffusion equation analyzes these temperature histories to determine the components of thermal diffusivity. Illustrative measurements in stainless steel, glass, and PVC demonstrate that accurate three-dimensional thermal diffusivity measurements can be made in this way. The in-plane components of thermal diffusivity of as-supplied PVC sheet are shown to be about 20 percent greater than the out-of-plane component. This anisotropy appears to be due to the manufacturing process and exemplifies the need for such measurements. [S0022-1481(00)70101-0]

A Video Super Resolution Algorithm Based on Wavelet Coefficient

2014 ◽  
Vol 610 ◽  
pp. 425-428
Author(s):  
Wei Jian Liu ◽  
Si Da Xiao ◽  
Ruo He Yao
Keyword(s):  
High Frequency ◽  
Wavelet Coefficient ◽  
Three Dimensional ◽  
Super Resolution ◽  
Structural Similarity ◽  
Image Sequences ◽  
Discrete Wavelet ◽  
Resolution Image ◽  
Resolution Algorithm ◽  
Visual Results

In this paper, we propose a new super-resolution algorithm based on wavelet coefficient. The proposed algorithm uses discrete wavelet transform (DWT) to decompose the input low-resolution image sequences into four subband images, including LL, LH, HL, HH. Then the input images have been processed by the 3DSKR (Three Dimensional Steering Kernel Regression) super resolution (SR) algorithm, and the result replaces the LL subband image, while the three high-frequency subband images have been interpolated. Finally, combining all these images to generate a new high-resolution image by using inverse DWT. Proposed method has been verified on Calendar and Foliage by Matlab software platform. The peak signal-to-noise (PSNR), structural similarity (SSIM) and visual results are compared, and show that the computational complexity of the proposed algorithm decline by 30 percent compared with the existing algorithm to obtain the approximate results.

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