Temat: noise detection - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Initial assumptions for the system of automatic detection and classification of aircraft noise events
Autorzy:: Bukała, Michał
Nowoświat, Artur
Chyla, Andrzej
Tematy:: aircraft noise
noise monitoring
noise detection
hałas lotniczy
monitoring hałasu
wykrywanie hałasu; Pokaż więcej
Wydawca:: Politechnika Poznańska. Instytut Mechaniki Stosowanej
Powiązania:: https://bibliotekanauki.pl/articles/2202414.pdf Link otwiera się w nowym oknie
Opis:: The present study undertakes the development and implementation of an algorithm for an automatic separation of acoustic events related to aircraft flights. The data are provided by noise monitoring stations operating as part of multi-point continuous noise measurement systems around small and medium-sized airports and helicopter landing sites in Poland. The article presents initial assumptions of the developed method based on the conclusions of the research. For this purpose, two different methods of airborne noise signal detection will be discussed. The first method is based on the analysis of the value of the changing rate of the signal being the difference between the value of the analysed sample and the value of the h-th previous sample of the recorded sound level time history. The second method uses a convolutional neural network operating on values recorded in 1/3-octave bands. The objective of the study is to examine the effectiveness and limitations of the selected methods on the collected representative input data.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Zastosowanie transformacji falkowej do detekcji i usuwania szumów z danych rastrowych
Applications of wavelet transform in noise detection and removal from raster data
Autorzy:: Pyka, K.
Tematy:: transformacja falkowa
jakość radiometryczna
detekcja szumów
wavelets transform
radiometric quality
noise detection; Pokaż więcej
Wydawca:: Stowarzyszenie Geodetów Polskich
Powiązania:: https://bibliotekanauki.pl/articles/130394.pdf Link otwiera się w nowym oknie
Opis:: W pracy zaproponowano zastosowanie transformacji falkowej do wykrywania szumów zawartych w danych rastrowych a następnie do usuwania szumów losowych. Omówiono syntetycznie problem szumów występujących w obrazach cyfrowych oraz stosowane metody ich usuwania. Przedstawiono najważniejsze cechy transformacji falkowej. Jako materiał badawczy wykorzystano fragmenty zdjęć lotniczych i wysokorozdzielczych obrazów satelitarnych. Analizowano także dane pseudo-rastrowe, jakimi są wysokościowe modele terenu o strukturze regularnej siatki. Badania potwierdziły możliwość formułowania wskaźników zawartości szumów, opartych na analizie kształtu rozkładów współczynników detali falkowych. Stwierdzono, że badanie kształtu histogramów komponentów falkowych może być zastosowane do porównywania zmian radiometrycznych następujących podczas przetwarzania obrazów. W pracy przedstawiono koncepcje wykorzystania falek do redukowania zawartości szumów losowych. Na podstawie pierwszych eksperymentów badawczych sformułowano problemy cząstkowe, których rozwiązanie powinno zagwarantować wysoka skuteczność metody redukcji szumów w dziedzinie transformaty falkowej.
In the present paper, the use of wavelet transformation for determining noise type and reduction of random noise from raster data, is proposed. Noise in the digital images and applied methods for noise removal is described synthetically. The most important features of wavelet transformation are presented. The fragments of aerial photographs and high-resolution satellite images were used as a research material. Besides the images, the pseudo-raster data, such as the area digital terrain models (DTM) with the regular grid structure, were analysed. The research confirmed the possibility to define the noise content indicators based on the analysis of wavelet detail coefficients distribution shape. It was found that the study of histogram shape of the wavelet components can be employed for the comparison of the radiometric changes occurring during radiometric and geometric processing of the images. In the paper, the concept of using wavelets for the reduction of the random noise content is presented. On the grounds of the experiments in preliminary research, the partial problems were formulated. Finding the solution to them should guarantee the efficiency of noise reduction method in the wavelet transformation field.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Noise Detection for Biosignals Using an Orthogonal Wavelet Packet Tree Denoising Algorithm
Autorzy:: Schimmack, M.
Mercorelli, P.
Tematy:: noise detection
wavelet packet transform
wavelet analysis
Daubechies wavelet
linux-based embedded system
ARM processor platform; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/226940.pdf Link otwiera się w nowym oknie
Opis:: This article deals with the noise detection of discrete biosignals using an orthogonal wavelet packet. In specific, it compares the usefulness of Daubechies wavelets with different vanishing moments for the denoising and compression of the digitalised biosignals in case of surface electromyography (sEMG) signals. The work is based upon the discrete wavelet transform (DWT) version of wavelet package transform (WPT). A noise reducing algorithm is proposed to detect unavoidable noise in the acquired data in a model independent way. The noise of a signal sequence will be defined by a seminorm. This method was developed for a possible observation during a fracture healing period. The proposed method is general for signal processing and its design was based upon the wavelet packet.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Impact of Edge Detection Algorithms in Medical Image Processing
Autorzy:: Anas, Ruba
Elhadi, Hadeel A.
Ali, Elmustafa Sayed
Tematy:: Canny
Edge detection
Gaussian Noise
LOG
Laplacian
Prewitt
Salt & Pepper Noise; Pokaż więcej
Wydawca:: Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Powiązania:: https://bibliotekanauki.pl/articles/1075754.pdf Link otwiera się w nowym oknie
Opis:: Imaging technology in Medicine let the doctors to see the interior portions of the body for easy diagnosis. It also helped doctors to make keyhole surgeries for reaching the interior parts without really opening too much of the body. Noise in medical images appears in an image from a variety sources or it is the random variation of brightness or color information in images. Edge detection is a common process in the treatment of medical images and it is a very useful task for object recognition of human organs. Edge detection also show where shadows fall in an image or any other distinct change in the intensity of an image due to noise effects. In this paper we evaluated the performance of different edge detection algorithms; Canny, Prewitt, LOG, and Laplacian with and without adding filer such as wiener and median. The statement of effectiveness in removing noise and preserving important information in medical image is identified by using quality measurements like PSNR and MSE. Results show that the best algorithm for displaying edge and removing salt & pepper noise is the Prewitt Algorithm after using the median filter. Additionally, it was found that the best algorithm for displaying edge and removing Gaussian noise is the Canny algorithm after using the median filter.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Recognition of anhydrite intercalated salt deposit from seismic dataset distorted by noise
Autorzy:: Kawalec-Latała, E.
Tematy:: underground storage
acoustic impedance
salt deposit
inhomogeneity detection
noise; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/178911.pdf Link otwiera się w nowym oknie
Opis:: Acoustic inversion is useful to extract information from seismic data. Inhomogeneities of salt deposits should be predicted before the decision of underground storage location is made. The work concerns the possibility of detecting anhydrite intercalation in the rock salt from seismic dataset. The resolution strongly depends on signal to noise ratio. The synthetic pseudoacoustic impedance sections are generated for efficiency test of predictive and minimum entropy deconvolution process, when random noise distorts the seismic traces.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Algorytmy przetwarzania widm Ramana podczas detekcji substancji chemicznych
Algorithms of Raman spectra processing during chemicals detection
Autorzy:: Kwiatkowski, A.
Tematy:: spektroskopia Ramana
algorytmy detekcji
zakłócenia
Raman spectroscopy
detection algorithms
noise; Pokaż więcej
Wydawca:: Politechnika Gdańska. Wydział Elektrotechniki i Automatyki
Powiązania:: https://bibliotekanauki.pl/articles/267815.pdf Link otwiera się w nowym oknie
Opis:: W pracy zostaną przedstawione algorytmy wstępnego przetwarzania widm mające na celu usuniecie lub zmniejszenie intensywności zakłóceń obecnych w rejestrowanych widmach Ramana, ze szczególnym uwzględnieniem automatyzacji tego procesu (bez konieczności wyboru parametrów przetwarzania przez obsługę urządzenia). Kolejna prezentowana grupę algorytmów stanowią procedury parametryzacji widm, które opisują widma w postaci zbioru kilku parametrów, np. pozycji linii widmowych, jej względnej amplitudy oraz szerokości. Parametry te są niezbędną informacja wejściową dla niektórych algorytmów detekcji. W pracy zostaną również zaprezentowane najpopularniejsze algorytmy korelacyjne oraz algorytmy porównujące położenie i amplitudę linii widmowych.
Detection of chemicals on the basis of their Raman spectra measurement consists in comparison recorded spectra for the tested chemical substances with model spectra stored in the master database. Detection algorithms indicate the substance of the database whose spectrum is the most similar, according to established criteria, to the recorded spectrum of the tested chemical. In the paper, there will be presented spectra preprocessing algorithms to eliminate or reduce the intensity of the noise present in the recorded Raman spectra, with particular emphasis on automation of this process (no need to select the parameters processed by the operation of the device). Another presented group of algorithms are spectra parameterization procedures that describe the spectrum as a set of several parameters, such as the position of the spectral lines, the relative amplitude and width. These parameters are necessary input information for some detection algorithms. The paper will also be presented to the most popular correlation algorithms.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Application of Artificial Neural Networks for Defect Detection in Ceramic Materials
Autorzy:: Akinci, T. C.
Nogay, H. S.
Yilmaz, O.
Tematy:: impulse noise
artificial neural network
ANN
defect detection
ceramic materials; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/176701.pdf Link otwiera się w nowym oknie
Opis:: In this study, an artificial neural network application was performed to tell if 18 plates of the same material in different shapes and sizes were cracked or not. The cracks in the cracked plates were of different depth and sizes and were non-identical deformations. This ANN model was developed to detect whether the plates under test are cracked or not, when four plates have been selected randomly from among a total of 18 ones. The ANN model used in the study is a model uniquely tailored for this study, but it can be applied to all systems by changing the weight values and without changing the architecture of the model. The developed model was tested using experimental data conducted with 18 plates and the results obtained mainly correspond to this particular case. But the algorithm can be easily generalized for an arbitrary number of items.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: The Defect Detection in Ceramic Materials Based on Time-Frequency Analysis by Using the Method of Impulse Noise
Autorzy:: Akinci, T. C.
Tematy:: impulse noise
time-frequency analysis
defect detection in ceramic materials; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/177471.pdf Link otwiera się w nowym oknie
Opis:: In this study, it was achieved by using the method of impulse noise to detect internal or surface cracks that can occur in the production of ceramic plates. Ceramic materials are often used in the industry, especially as kitchenware and in areas such as the construction sector. Many different methods are used in the quality assurance processes of ceramic materials. In this study, the impact noise method was examined. This method is a test technique that was not used in applications. The method is presented as an examination technique based on whether there is a deformation on the material according to the sound coming from it as a result of a plastic bit hammer impact on the ceramic material. The application of the study was performed on plates made of ceramic materials. Here, it was made with the same type of model plates manufactured from the same material. The noise that would occur as a result of the impact applied on a point determined on the materials to be tested has been examined by the method of time-frequency analysis. The method applied gives pretty good results for distinguishing ceramic plates in good condition from those which are cracked.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: An acoustic sea glider for deep-sea noise profiling using an acoustic vector sensor
Autorzy:: Sun, Qindong
Zhou, Hongkun
Tematy:: acoustic sea glider
acoustic vector sensor
ambient sea noise
target detection; Pokaż więcej
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Powiązania:: https://bibliotekanauki.pl/articles/32889290.pdf Link otwiera się w nowym oknie
Opis:: An acoustic sea glider has been developed for ambient sea noise measurement and target detection through the deployment of an acoustic vector sensor (AVS). The glider was designed with three cabins connected in sequence and it can dive to depths exceeding 1200m. The AVS fixed on the glider measure acoustic pressure and particle velocities related to undersea noise, and the inner attitude sensors can effectively eliminate the estimation deviation of the direction of arrival. The inherent self-noises of the acoustic sea glider and AVS are presented respectively in respect to the Knudsen spectra of sea noise. Sea trial results indicate that the AVS could work well for undersea noise measurement when the glider is smooth sliding, and the target azimuth estimated by AVS after correction is remarkably consistent with the values measured by the GPS, and direction-finding errors are less than 10 degrees. The research in this paper shows that the acoustic sea glider is able to undertake tasks such as a wide range of underwater acoustic measurement and detection.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Measurements of low frequency noise of infrared photo-detectors with transimpedance detection system
Autorzy:: Ciura, Ł.
Kolek, A.
Gawron, W.
Kowalewski, A.
Stanaszek, D.
Tematy:: 1/f noise
infrared detectors
nBn structure
HgCdTe heterostructures
noise measurements
transimpedance detection system
type II InAs/GaSb superlattice; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/221094.pdf Link otwiera się w nowym oknie
Opis:: The paper presents the method and results of low-frequency noise measurements of modern mid-wavelength infrared photodetectors. A type-II InAs/GaSb superlattice based detector with nBn barrier architecture is compared with a high operating temperature (HOT) heterojunction HgCdTe detector. All experiments were made in the range 1 Hz - 10 kHz at various temperatures by using a transimpedance detection system, which is examined in detail. The power spectral density of the nBn’s dark current noise includes Lorentzians with different time constants while the HgCdTe photodiode has more uniform 1/f - shaped spectra. For small bias, the low-frequency noise power spectra of both devices were found to scale linearly with bias voltage squared and were connected with the fluctuations of the leakage resistance. Leakage resistance noise defines the lower noise limit of a photodetector. Other dark current components give raise to the increase of low-frequency noise above this limit. For the same voltage biasing devices, the absolute noise power densities at 1 Hz in nBn are 1 to 2 orders of magnitude lower than in a MCT HgCdTe detector. In spite of this, low-frequency performance of the HgCdTe detector at ~ 230K is still better than that of InAs/GaSb superlattice nBn detector.
Dostawca treści:: Biblioteka Nauki

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