Evaluation of high‐resolution frequency estimation methods for determining frequencies of eigenmodes in shallow water acoustic field

1993 ◽  
Vol 93 (1) ◽  
pp. 378-389 ◽  
Author(s):  
Subramaniam D. Rajan ◽  
Saurav D. Bhatta
Keyword(s):  
High Resolution ◽  
Shallow Water ◽  
Acoustic Field ◽  
Frequency Estimation ◽  
Estimation Methods

scholarly journals A Coupling Graphic Pipeline with Normal Mode Model for Rapid Calculation of Underwater Acoustic Field

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Jianghao Zhuo ◽  
Ling Wang ◽  
Ke Xu ◽  
Jianwei Wan
Keyword(s):  
High Resolution ◽  
Shallow Water ◽  
Normal Mode ◽  
Acoustic Field ◽  
Sound Field ◽  
Underwater Acoustic ◽  
Matlab Code ◽  
Acoustic Modelling ◽  
Rapid Calculation ◽  
Execution Speed

Rapid execution is required in operation-oriented applications in underwater acoustic modelling. In this paper, the GPU graphic pipeline is used to accelerate the calculation of high-resolution sound field image in the normal mode model of underwater acoustic propagation. The computer times of the proposed graphic pipeline method, the MATLAB code, and the C# code are compared for a stratified shallow water waveguide using the KRAKEN model at different frequencies. The research validates that the graphic pipeline method outperforms the classic CPU-based methods in terms of execution speed at the frequencies where the eigenvalue equation in normal mode models can be solved.

APPLICATION OF THE HIGH-RESOLUTION RANS/ILES TECHNOLOGY FOR FLOW SIMULATION AND THE NEARBY ACOUSTIC FIELD OF NEAR-WALL JETS AND MIXING LAYERS

2016 ◽  
Vol 47 (2) ◽  
pp. 159-183 ◽  
Author(s):  
Leonid Aleksandrovich Bendersky ◽  
Dmitriy Aleksandrovich Lyubimov ◽  
Irina Vasilevna Potekhina ◽  
Alena Eduardovna Fedorenko
Keyword(s):  
High Resolution ◽  
Acoustic Field ◽  
Flow Simulation ◽  
Mixing Layers ◽  
Wall Jets ◽  
Near Wall

scholarly journals Multi-Scene Building Height Estimation Method Based on Shadow in High Resolution Imagery

2021 ◽  
Vol 13 (15) ◽  
pp. 2862
Author(s):  
Yakun Xie ◽  
Dejun Feng ◽  
Sifan Xiong ◽  
Jun Zhu ◽  
Yangge Liu
Keyword(s):  
Remote Sensing ◽  
High Resolution ◽  
Estimation Method ◽  
Absolute Error ◽  
Large Error ◽  
Estimation Methods ◽  
Height Estimation ◽  
Building Height ◽  
Remote Sensing Imagery ◽  
High Resolution Imagery

Accurately building height estimation from remote sensing imagery is an important and challenging task. However, the existing shadow-based building height estimation methods have large errors due to the complex environment in remote sensing imagery. In this paper, we propose a multi-scene building height estimation method based on shadow in high resolution imagery. First, the shadow of building is classified and described by analyzing the features of building shadow in remote sensing imagery. Second, a variety of shadow-based building height estimation models is established in different scenes. In addition, a method of shadow regularization extraction is proposed, which can solve the problem of mutual adhesion shadows in dense building areas effectively. Finally, we propose a method for shadow length calculation combines with the fish net and the pauta criterion, which means that the large error caused by the complex shape of building shadow can be avoided. Multi-scene areas are selected for experimental analysis to prove the validity of our method. The experiment results show that the accuracy rate is as high as 96% within 2 m of absolute error of our method. In addition, we compared our proposed approach with the existing methods, and the results show that the absolute error of our method are reduced by 1.24 m-3.76 m, which can achieve high-precision estimation of building height.

scholarly journals Shallow water seagrass observed by high resolution full waveform bathymetric LiDAR

2014 ◽  
Author(s):  
Zhigang Pan ◽  
Juan Carlos Fernandez-Diaz ◽  
Craig L. Glennie ◽  
Michael Starek
Keyword(s):  
High Resolution ◽  
Shallow Water ◽  
Full Waveform

A Comparison of Beat Frequency Estimation Methods for Large Ring Laser

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Jailos Mrisho Nzumile ◽  
Keyword(s):  
Real Time ◽  
Noise Level ◽  
Ring Laser ◽  
Frequency Estimation ◽  
Low Noise ◽  
Estimation Methods ◽  
Acquisition Rate ◽  
Large Ring ◽  
True Value ◽  
Output Characteristics

Autoregressive (AR2) technique has always been used to estimate frequency of the output signal from Large ring laser. However, the acquisition rate is not at near real time which is the requirement and noise level still challenge the process resulting to errors in the final estimation. A research was done to compare the Autoregressive (AR2) with the counterparts such as Pisarenko, Quinn, Hilbert and Phase looking for a better technique that will estimate the frequency at near real time to minimize errors. Secondary data from G and C – II ring laser were used during the comparison between the techniques and Autoregressive (AR2). Results shows that, the output characteristics from the counterpart does not depict the oscillations of the Earth rotation as expected contrast to that of Autoregressive (AR2) which does. Moreover, there were much deviation from the expected true value for the techniques contrast to that of AR2 which is very minimum. On the other hand, when the C – II data were used, it was observed that both techniques resemble on their output characteristics though AR2 was still better in the acquisition rate expect for Hilbert transform which does not resemble with others. Following the scope of this paper, Autoregressive (AR2) technique still emerge as a favorite frequency estimation technique contrast to the four counterparts due to its robustness, high acquisition rate as well as low noise level.

Sign in / Sign up

Export Citation Format

Share Document