scholarly journals Sound wave separation method based on spatial signals resampling with single layer microphone array

2014 ◽  
Vol 63 (19) ◽  
pp. 194305
Author(s):  
Song Yu-Lai ◽  
Lu Huan-Cai ◽  
Jin Jiang-Ming
Sensors ◽  
2020 ◽  
Vol 20 (12) ◽  
pp. 3527
Author(s):  
Ching-Feng Liu ◽  
Wei-Siang Ciou ◽  
Peng-Ting Chen ◽  
Yi-Chun Du

In the context of assisted human, identifying and enhancing non-stationary speech targets speech in various noise environments, such as a cocktail party, is an important issue for real-time speech separation. Previous studies mostly used microphone signal processing to perform target speech separation and analysis, such as feature recognition through a large amount of training data and supervised machine learning. The method was suitable for stationary noise suppression, but relatively limited for non-stationary noise and difficult to meet the real-time processing requirement. In this study, we propose a real-time speech separation method based on an approach that combines an optical camera and a microphone array. The method was divided into two stages. Stage 1 used computer vision technology with the camera to detect and identify interest targets and evaluate source angles and distance. Stage 2 used beamforming technology with microphone array to enhance and separate the target speech sound. The asynchronous update function was utilized to integrate the beamforming control and speech processing to reduce the effect of the processing delay. The experimental results show that the noise reduction in various stationary and non-stationary noise environments were 6.1 dB and 5.2 dB respectively. The response time of speech processing was less than 10ms, which meets the requirements of a real-time system. The proposed method has high potential to be applied in auxiliary listening systems or machine language processing like intelligent personal assistant.


2013 ◽  
Vol 291-294 ◽  
pp. 2325-2330
Author(s):  
Hong Ling Xie ◽  
Fei Wang ◽  
Yan Qing Li ◽  
Fei Long Wang

The use of direct wave to locate the position of the PD source is of better accuracy in transformer partial discharge ultrasound array positioning. For the signal received by ultrasonic sensor is consisted by direct wave, non-direct wave and a variety of noise, a direct wave separation method based on improved waveform matching is proposed in this paper. It is considered that the direct wave first reaches the ultrasonic sensor. A benchmarks triangle is built and then the attenuation coefficient and the signal frequency are both calculated. In order to search the matching wave, the benchmarks triangle is to pan and zoom. Finally, the best matching waveform is selected from a large number of matching waveforms as a direct wave signal. The result of simulation shows that the method can isolate the ultrasonic direct wave signal from the received signal, which provides some theoretical guidance to improve the position accuracy of the PD source.


2014 ◽  
Vol 41 (6) ◽  
pp. 771-777 ◽  
Author(s):  
Jixiang XU ◽  
B F McLean ◽  
Xuejuan SONG

2021 ◽  
Author(s):  
Rahul Manoj ◽  
V Raj Kiran ◽  
P M Nabeel ◽  
Mohanasankar Sivaprakasam ◽  
Jayaraj Joseph

2017 ◽  
Vol 26 (2) ◽  
pp. 229-250 ◽  
Author(s):  
Zijian Wang ◽  
Pizhong Qiao

In this paper, a backward wave separation method is proposed. Since the first backward wave can be considered as the damage reflection, the damage reflected wave peaks are artificially amplified by appropriately shifting and summing signals collected from a series of sensing points aligned along the wave propagating direction. This shifting and summing process aims to present the damage reflected wave peaks more distinctively while offsets randomly distributed environmental interferences. Due to the high signal-to-noise ratio of the treated signal, the application of backward wave separation is able to attain baseline-free damage detection. A circular single transmitter and multi-receiver sensor array is then deployed on a metal plate to identify the crack-like damage. Signals collected by the sensor array with and without the treatment of the backward wave separation method are, respectively, imported to the delay-and-sum imaging algorithm to yield individual damage contours. The comparisons between these contours demonstrate that the backward wave separation method is able to significantly improve the damage identification performance of the sensor array with respect to the damage localization accuracy, noise immunity, and damage sensitivity. Both the finite element modeling and laser measurement are conducted to validate the effectiveness of the proposed backward wave separation method.


Author(s):  
Murray Stewart ◽  
T.J. Beveridge ◽  
D. Sprott

The archaebacterium Methanospirillum hungatii has a sheath as part of its cell wall which is composed mainly of protein. Treatment with dithiothreitol or NaOH released the intact sheaths and electron micrographs of this material negatively stained with uranyl acetate showed flattened hollow tubes, about 0.5 μm diameter and several microns long, in which the patterns from the top and bottom were superimposed. Single layers, derived from broken tubes, were also seen and were more simply analysed. Figure 1 shows the general appearance of a single layer. There was a faint axial periodicity at 28.5 A, which was stronger at irregular multiples of 28.5 A (3 and 4 times were most common), and fine striations were also seen at about 3° to the tube axis. Low angle electron diffraction patterns (not shown) and optical diffraction patterns (Fig. 2) from these layers showed a complex meridian (as a result of the irregular nature of the repeat along the tube axis) which showed a clear maximum at 28.5 A, consistent with the basic subunit spacing.


Author(s):  
Maria Anna Pabst

In addition to the compound eyes, honeybees have three dorsal ocelli on the vertex of the head. Each ocellus has about 800 elongated photoreceptor cells. They are paired and the distal segment of each pair bears densely packed microvilli forming together a platelike fused rhabdom. Beneath a common cuticular lens a single layer of corneagenous cells is present.Ultrastructural studies were made of the retina of praepupae, different pupal stages and adult worker bees by thin sections and freeze-etch preparations. In praepupae the ocellar anlage consists of a conical group of epidermal cells that differentiate to photoreceptor cells, glial cells and corneagenous cells. Some photoreceptor cells are already paired and show disarrayed microvilli with circularly ordered filaments inside. In ocelli of 2-day-old pupae, when a retinogenous and a lentinogenous cell layer can be clearly distinguished, cell membranes of the distal part of two photoreceptor cells begin to interdigitate with each other and so start to form the definitive microvilli. At the beginning the microvilli often occupy the whole width of the developing rhabdom (Fig. 1).


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