Adaptive Echo Cancellation Combined with Delay Estimation

2013 ◽  
Vol 303-306 ◽  
pp. 2072-2075
Author(s):  
Zhi Ping Zhang ◽  
Xi Hong Wu
Keyword(s):  
Adaptive Filters ◽  
Signal To Noise Ratio ◽  
Low Complexity ◽  
The Other ◽  
Echo Cancellation ◽  
Delay Estimation ◽  
Delay Compensation ◽  
Echo Canceller ◽  
Signal To Noise ◽  
Echo Delay

This paper proposed an echo canceller to reduce the computational complexity of the long delay echo cancellation. Two adaptive filters were used for constructing this echo canceller. One was designed as a delay estimator, which used down-sampled sub-band signals to estimate the echo delay time. The other was designed as a short-tap filter to subtract the echo from the recorded signal with delay compensation. Experimental results showed that the output signal-to-noise ratio from the proposed canceller with low complexity is similar to that from the conventional canceller based on a long-tap filter.

scholarly journals Applying Ateb–Gabor Filters to Biometric Imaging Problems

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 717
Author(s):  
Mariia Nazarkevych ◽  
Natalia Kryvinska ◽  
Yaroslav Voznyi
Keyword(s):  
Wavelet Transformation ◽  
Symmetric Functions ◽  
Gabor Filter ◽  
Signal To Noise Ratio ◽  
The Other ◽  
Mean Square ◽  
Image Transformation ◽  
Gabor Filtering ◽  
Signal To Noise ◽  
Filtration Method

This article presents a new method of image filtering based on a new kind of image processing transformation, particularly the wavelet-Ateb–Gabor transformation, that is a wider basis for Gabor functions. Ateb functions are symmetric functions. The developed type of filtering makes it possible to perform image transformation and to obtain better biometric image recognition results than traditional filters allow. These results are possible due to the construction of various forms and sizes of the curves of the developed functions. Further, the wavelet transformation of Gabor filtering is investigated, and the time spent by the system on the operation is substantiated. The filtration is based on the images taken from NIST Special Database 302, that is publicly available. The reliability of the proposed method of wavelet-Ateb–Gabor filtering is proved by calculating and comparing the values of peak signal-to-noise ratio (PSNR) and mean square error (MSE) between two biometric images, one of which is filtered by the developed filtration method, and the other by the Gabor filter. The time characteristics of this filtering process are studied as well.

scholarly journals Geometric Approach to Analytic Marginalisation of the Likelihood Ratio for Continuous Gravitational Wave Searches

Universe ◽  
2021 ◽  
Vol 7 (6) ◽  
pp. 174
Author(s):  
Karl Wette
Keyword(s):  
Gravitational Wave ◽  
Likelihood Ratio ◽  
Signal To Noise Ratio ◽  
Geometric Approach ◽  
The Other ◽  
Efficient Computation ◽  
Likelihood Ratios ◽  
Signal To Noise ◽  
Noise Ratio ◽  
Optimal Signal

The likelihood ratio for a continuous gravitational wave signal is viewed geometrically as a function of the orientation of two vectors; one representing the optimal signal-to-noise ratio, and the other representing the maximised likelihood ratio or F-statistic. Analytic marginalisation over the angle between the vectors yields a marginalised likelihood ratio, which is a function of the F-statistic. Further analytic marginalisation over the optimal signal-to-noise ratio is explored using different choices of prior. Monte-Carlo simulations show that the marginalised likelihood ratios had identical detection power to the F-statistic. This approach demonstrates a route to viewing the F-statistic in a Bayesian context, while retaining the advantages of its efficient computation.

Peak Signal-to-Noise Ratio Evaluation of Server Display Monitors and Client Display Monitors in a Digital Subtraction Angiography Devices

2020 ◽  
Vol 3 (1) ◽  
pp. 33-41
Author(s):  
Hwunjae Lee ◽  
◽  
Junhaeng Lee ◽  
Keyword(s):  
Signal To Noise Ratio ◽  
Information Loss ◽  
The Other ◽  
Digital Subtraction ◽  
Signal Distortion ◽  
Signal To Noise ◽  
Image Storage ◽  
And Performance ◽  
Pacs Server ◽  
Display Monitor

This study evaluated PSNR of server display monitor and client display monitor of DSA system. The signal is acquired and imaged during the surgery and stored in the PACS server. After that, distortion of the original signal is an important problem in the process of observation on the client monitor. There are many problems such as noise generated during compression and image storage/transmission in PACS, information loss during image storage and transmission, and deterioration in image quality when outputting medical images from a monitor. The equipment used for the experiment in this study was P's DSA. We used two types of monitors in our experiment, one is P’s company resolution 1280×1024 pixel monitor, and the other is W’s company resolution 1536×2048 pixel monitor. The PACS Program used MARO-view, and for the experiment, a PSNR measurement program using Visual C++ was implemented and used for the experiment. As a result of the experiment, the PSNR value of the kidney angiography image was 26.958dB, the PSNR value of the lung angiography image was 28.9174 dB, the PSNR value of the heart angiography image was 22.8315dB, and the PSNR value of the neck angiography image was 37.0319 dB, and the knee blood vessels image showed a PSNR value of 43.2052 dB, respectively. In conclusion, it can be seen that there is almost no signal distortion in the process of acquiring, storing, and transmitting images in PACS. However, it suggests that the image signal may be distorted depending on the resolution and performance of each monitor. Therefore, it will be necessary to evaluate the performance of the monitor and to maintain the performance.

scholarly journals Discovery of allenyl acetylene, H2CCCHCCH, in TMC-1

2021 ◽  
Vol 647 ◽  
pp. L3 ◽  
Author(s):  
J. Cernicharo ◽  
C. Cabezas ◽  
M. Agúndez ◽  
B. Tercero ◽  
N. Marcelino ◽  
...  
Keyword(s):  
Column Density ◽  
State Of The Art ◽  
Rotational Temperature ◽  
Signal To Noise Ratio ◽  
Laboratory Data ◽  
The Other ◽  
Signal To Noise ◽  
Chemical Models ◽  
Upper Limit

We present the discovery in TMC-1 of allenyl acetylene, H2CCCHCCH, through the observation of nineteen lines with a signal-to-noise ratio ∼4–15. For this species, we derived a rotational temperature of 7 ± 1 K and a column density of 1.2 ± 0.2 × 1013 cm−2. The other well known isomer of this molecule, methyl diacetylene (CH3C4H), has also been observed and we derived a similar rotational temperature, Tr = 7.0 ± 0.3 K, and a column density for its two states (A and E) of 6.5 ± 0.3 × 1012 cm−2. Hence, allenyl acetylene and methyl diacetylene have a similar abundance. Remarkably, their abundances are close to that of vinyl acetylene (CH2CHCCH). We also searched for the other isomer of C5H4, HCCCH2CCH (1.4-Pentadiyne), but only a 3σ upper limit of 2.5 × 1012 cm−2 to the column density can be established. These results have been compared to state-of-the-art chemical models for TMC-1, indicating the important role of these hydrocarbons in its chemistry. The rotational parameters of allenyl acetylene have been improved by fitting the existing laboratory data together with the frequencies of the transitions observed in TMC-1.

A low-PDAP and high-PSNR approximate 4:2 compressor cell in CNFET technology

Circuit World ◽  
2019 ◽  
Vol 45 (3) ◽  
pp. 156-168 ◽  
Author(s):  
Yavar Safaei Mehrabani ◽  
Mehdi Bagherizadeh ◽  
Mohammad Hossein Shafiabadi ◽  
Abolghasem Ghasempour
Keyword(s):  
Image Processing ◽  
Design Methodology ◽  
Figure Of Merit ◽  
Signal To Noise Ratio ◽  
Monte Carlo Analysis ◽  
The Other ◽  
Threshold Logic ◽  
Signal To Noise ◽  
Content Type ◽  
Power Delay Product

Purpose This paper aims to present an inexact 4:2 compressor cell using carbon nanotube filed effect transistors (CNFETs). Design/methodology/approach To design this cell, the capacitive threshold logic (CTL) has been used. Findings To evaluate the proposed cell, comprehensive simulations are carried out at two levels of the circuit and image processing. At the circuit level, the HSPICE software has been used and the power consumption, delay, and power-delay product are calculated. Also, the power-delaytransistor count product (PDAP) is used to make a compromise between all metrics. On the other hand, the Monte Carlo analysis has been used to scrutinize the robustness of the proposed cell against the variations in the manufacturing process. The results of simulations at this level of abstraction indicate the superiority of the proposed cell to other circuits. At the application level, the MATLAB software is also used to evaluate the peak signal-to-noise ratio (PSNR) figure of merit. At this level, the two primary images are multiplied by a multiplier circuit consisting of 4:2 compressors. The results of this simulation also show the superiority of the proposed cell to others. Originality/value This cell significantly reduces the number of transistors and only consists of NOT gates.

A Different Approach to the Noise Problem of the Hearing Impaired

1993 ◽  
Vol 2 (2) ◽  
pp. 47-51 ◽  
Author(s):  
Edgar Villchur
Keyword(s):  
Steady State ◽  
Adaptive Filters ◽  
Signal To Noise Ratio ◽  
Hearing Impaired ◽  
Redundant Information ◽  
Signal To Noise ◽  
Directional Microphones ◽  
Selective Listening ◽  
Speech Cues ◽  
Noise Ratio

Hearing aid design to alleviate the noise problem has concentrated on improving the signal-to-noise ratio with the aid, using devices such as directional microphones, adaptive filters, and circuits that discriminate between steady-state noise and speech. The design approach discussed here is directed at improving the speech recognition of hearing-impaired listeners at a given signal-to-noise ratio, by restoring to their perception speech cues they no longer hear because of their impairment. This allows them to retain more of the redundant information in speech after masking has taken its toll, and empowers their ability to separate desired from undesired signals (what Broadbent calls "selective listening" in persons with normal hearing). Experimental results are presented.

scholarly journals Analysis of the reliability of LoRa

2020 ◽  
Author(s):  
Qahhar Muhammad Qadir
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Coverage Probability ◽  
Stochastic Geometry ◽  
Signal To Noise Ratio ◽  
Low Complexity ◽  
Signal To Noise ◽  
Coverage Probabilities ◽  
Form Model ◽  
Simulation Results

This letter studies the performance of a single gateway LoRa system in the presence of different interference considering the imperfect orthogonality effect. It utilizes concepts of stochastic geometry to present a low-complexity approximate closed-form model for computing the success and coverage probabilities under these challenging conditions. Monte Carlo simulation results have shown that LoRa is not as theoretically described as a technology that can cover few to ten kilometers. It was found that in the presence of the combination of signal-to-noise ratio (SNR) and imperfect orthogonality between spreading factors (SF), the performance degrades dramatically beyond a couple of kilometers. However, better performance is observed when perfect orthogonality is considered and SNR is not included. Furthermore, the performance is annulus dependent and slightly improves at the border of the deployment cell annuli. Finally, the coverage probability declines exponentially as the average number of end devices grows.

MICROPHONE ARRAY SYSTEM IN ACOUSTICAL SOURCE LOCALIZATION USING LEAST SQUARE ESTIMATION

1996 ◽  
Vol 06 (06) ◽  
pp. 581-591
Author(s):  
MING JIAN ◽  
ALEX C. KOT ◽  
MENG H. ER
Keyword(s):  
Source Localization ◽  
Time Delays ◽  
Signal To Noise Ratio ◽  
Microphone Array ◽  
Time Delay Estimation ◽  
Least Square ◽  
Delay Estimation ◽  
Signal To Noise ◽  
Least Square Estimation ◽  
Five Elements

In this paper, we address the problem of acoustical source localization using a five-elements microphone array system. The time delay estimation of signal arrival for any given pair of microphones using least square technique is proposed. These estimated time delays are used in the geometric location method to determine the location of the acoustical source which, in our case, is the position of talker of interest. Computer simulations are carried out in a teleconferencing room scenario. It is shown that the location of the acoustical source can be estimated effectively as signal-to-noise ratio is larger than 20 dB in a high reverberation environment.

scholarly journals Time Delay Estimation Method Used Median Filter in Low Signal to Noise Ratio Pulse Environment

2021 ◽  
Vol 252 ◽  
pp. 02039
Author(s):  
Hang Liu ◽  
Wenhong Liu
Keyword(s):  
Signal Processing ◽  
Time Delay ◽  
Signal To Noise Ratio ◽  
Median Filter ◽  
Estimation Algorithm ◽  
Time Delay Estimation ◽  
Delay Estimation ◽  
P Value ◽  
Signal To Noise ◽  
Second Order Statistics

In practice, the collected signal often contains impulsive noise. The classical time delay estimation algorithm based on the second-order statistics of Gaussian distribution will degrade or even be unreliable, so that it cannot be used. Although the fractional low-order signal processing method can be better adapted to signal processing in the impulse noise environment, the determination of the order p value of the fractional low-order moment depends on the prior knowledge or estimation of the characteristic index α value of the pulse, and when the pulse is stronger or the signal-to-noise ratio is low, the performance cannot meet the requirements well. The paper adopted the method of median filter preprocessing. First, the abnormal points (pulse points) are removed in the noise and return the noise to the Gaussian model distribution; next, use the time delay estimation algorithm under the second-order statistics to avoid the estimate of p-value. Computer simulation experiments show that the method proposed in this paper has better estimation performance in low snr pulse environment.

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