Temat: Filtering - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: An application of robust filters in ECG signal processing
Autorzy:: Pander, T.
Powiązania:: https://bibliotekanauki.pl/articles/333513.pdf
Data publikacji:: 2006
Wydawca:: Uniwersytet Śląski. Wydział Informatyki i Nauki o Materiałach. Instytut Informatyki. Zakład Systemów Komputerowych
Tematy:: filtrowanie robust
EKG
EMG
filtrowanie mean-median
robust filtering
ECG
mean-median filtering
Opis:: Robust filtering is a very promising area in application of biomedical signal processing. Signals are usually recorded with noise, which has various characteristics of baseline wander to very impulsive nature. The robust technique has been recently proposed as the tool to eliminate outliers in data samples. The main purpose of this paper is to present mean-median filters in application of ECG signal processing. The presented filter is evaluated in the presence of real muscle noise and simulated impulsive noise as a Gaussian-Laplace mixture. In order to suppress a noise with the best possible means, the special expression is proposed. The measure of distortions, which are introduced to a signal after operation of filtering, is estimated using the normalized mean square error. This factor is used to compare a quality of considered filters. Experimental results show improved performance according to the reference filters.
Źródło:: Journal of Medical Informatics & Technologies; 2006, 10; 113-123
1642-6037
Pojawia się w:: Journal of Medical Informatics & Technologies
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Colour video filtering based on vector order-statistics
Autorzy:: Lukac, R.
Smolka, B.
Bieda, R.
Budzan, S.
Powiązania:: https://bibliotekanauki.pl/articles/333243.pdf
Data publikacji:: 2003
Wydawca:: Uniwersytet Śląski. Wydział Informatyki i Nauki o Materiałach. Instytut Informatyki. Zakład Systemów Komputerowych
Tematy:: kolorowe filtrowanie wideo
hałas impulsowy
statystyka uporządkowana
filtrowanie wektorowe
colour video filtering
impulsive noise
order statistics
vector filtering
Opis:: The paper introduces a multichannel filtering approach for colour video denoising taking advantage of an order-statistic theory for vector-valued image signals. The proposed adaptive vector filter utilizes switching between an identity operation and a directional distance smoothing function based on the trimmed set of lowest ranked multichannel samples. Because the proposed method uses the same ordering scheme as the standard vector filters, the computational complexity of the new method is computationally attractive. Moreover, the method outperforms the standard vector filters especially in terms of signal-detail preservation. In this paper, we analyse a three-dimensional filter structure based on a cube filter window spawning 27 samples of three following frames. Thus, the proposed algorithm can be applied for the filtering of spatio-temporal or time-varying vector-valued image signals such as colour image sequences or colour video.
Źródło:: Journal of Medical Informatics & Technologies; 2003, 5; MI31-38
1642-6037
Pojawia się w:: Journal of Medical Informatics & Technologies
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: An attempt to improve Eigenface algorithm efficiency for colour images
Autorzy:: Orczyk, T.
Porwik, P.
Powiązania:: https://bibliotekanauki.pl/articles/333031.pdf
Data publikacji:: 2010
Wydawca:: Uniwersytet Śląski. Wydział Informatyki i Nauki o Materiałach. Instytut Informatyki. Zakład Systemów Komputerowych
Tematy:: rozpoznanie twarzy
filtrowanie kolorowe
face recognition
PCA
eigenface
colour filtering
Opis:: This article presents an attempt to improve Eigenface algorithm efficiency by using image pre–filtering in order to eliminate background areas of the picture and illumination influence. The background is treated as noise, so when noise is present then efficiency of the algorithm decreases. In order to eliminating this inconvenience, analysed image is pre–filtered by means of the colour classifier. The classifier eliminates pixels which have different colour than an average human skin colour on a digital photo. This causes that the Eigenface algorithm is less sensitive to background noise. The illumination influence was minimized by using hue information instead of traditionally used luminance. The main advantage of the proposed approach is possibility of using in environments where diverse image background texture and scene illumination appears. The eigenfaces technique can be applied in handwriting analysis, voice recognition, hand gestures interpretation and medical imaging.
Źródło:: Journal of Medical Informatics & Technologies; 2010, 16; 201-207
1642-6037
Pojawia się w:: Journal of Medical Informatics & Technologies
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Switching median filter with a local entropy control
Autorzy:: Lukac, R.
Smolka, B.
Bieda, R.
Budzan, S.
Powiązania:: https://bibliotekanauki.pl/articles/333245.pdf
Data publikacji:: 2003
Wydawca:: Uniwersytet Śląski. Wydział Informatyki i Nauki o Materiałach. Instytut Informatyki. Zakład Systemów Komputerowych
Tematy:: zakłócenia impulsowe
nieliniowa filtracja
impulsive noise
nonlinear filtering
switching median filter
Opis:: This paper presents a new switching median filter utilising local contrast entropy of the samples inside the filtering window. The proposed method is fully adaptive, it requires no optimisation and eliminates the main disadvantages of the local contrast probability based switching median. Excellent performance of the proposed method is a result of the successful analysis of input samples, as the local contrast entropy concept is able to efficiently differentiate between outliers and desired edge samples.
Źródło:: Journal of Medical Informatics & Technologies; 2003, 5; MI39-46
1642-6037
Pojawia się w:: Journal of Medical Informatics & Technologies
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Filtering of two-dimensional digital images using weighted averaging for adaptive selection of weights
Autorzy:: Momot, A.
Wrobel, J.
Horoba, K.
Jeżewski, M.
Bernys, M.
Powiązania:: https://bibliotekanauki.pl/articles/951702.pdf
Data publikacji:: 2012
Wydawca:: Uniwersytet Śląski. Wydział Informatyki i Nauki o Materiałach. Instytut Informatyki. Zakład Systemów Komputerowych
Tematy:: filtracja obrazów
ważone uśrednianie
image filtering
weighted averaging
adaptive selection of weights
Opis:: Many digital images, especially in biomedical fields, contain some disturbances. The image analysis depends on quality of the images that is why reduction or elimination (if it is possible) the disturbances is the key issue. There are many methods of improvement in the quality of the images and thus improve the quality of the image analysis, among them one of the simplest method is low-pass filtering such as arithmetic mean or its generalization, weighted mean. The basic problem of the weighted mean is the proper selection of the weights. This can be done using adaptive algorithms. This paper presents several such algorithms which are modifications of the existing weighted averaging methods created originally for noise reduction in electrocardiographic signal. The description of the new filtering methods and a few results of its application are also presented with comparison to existing arithmetic average filtering.
Źródło:: Journal of Medical Informatics & Technologies; 2012, 20; 93-99
1642-6037
Pojawia się w:: Journal of Medical Informatics & Technologies
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Adaptive impulse detection based approaches for the noise reduction in heart image sequences
Autorzy:: Smolka, B.
Lukac, R.
Powiązania:: https://bibliotekanauki.pl/articles/332867.pdf
Data publikacji:: 2002
Wydawca:: Uniwersytet Śląski. Wydział Informatyki i Nauki o Materiałach. Instytut Informatyki. Zakład Systemów Komputerowych
Tematy:: sekwencja serca
zakłócenia impulsowe
nieliniowa filtracja
mediana filtra
heart sequence
impulse noise
non-linear filtering
median filter
Opis:: This paper focuses on three-dimensional (3-D) adaptive median filters based on the impulse detection approach designed to effectively remove the impulse noise from cardiographic image sequences. Impulse noise affects the useful information in the form of bit errors and it introduces to the image high frequency changes that prohibit to process and to evaluate the heart dynamics correctly. Therefore biomedical imaging such as vascular imaging and quantification of heart dynamics is closely related to digital filtering. In order to suppress impulse noise effectively, well-known non-linear filters based on the robust order-statistic theory provide interesting results. Although median filters have excellent impulse noise attenuation characteristics, their performance is often accompanied by undesired processing of noise-free samples resulting in edge blurring. The reason is that median filters do not satisfy the superposition property and thus the optimal filtering situation where only noisy samples are affected can never be fully obtained. The presented adaptive impulse detection based median filters, can achieve the excellent balance between the noise suppression and the signal-detail preservation. In this paper, the performance of the proposed approaches is successfully tested for the heart image sequence of 38 frames and the wide range of noise corruption intensity. The results are evaluated in terms of mean absolute error, mean square error and cross correlation.
Źródło:: Journal of Medical Informatics & Technologies; 2002, 3; MI21-29
1642-6037
Pojawia się w:: Journal of Medical Informatics & Technologies
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Separation of abdominal fetal electrocardiograms in twin pregnancy
Autorzy:: Kotas, M.
Jeżewski, J.
Matonia, A.
Kupka, T.
Powiązania:: https://bibliotekanauki.pl/articles/333491.pdf
Data publikacji:: 2008
Wydawca:: Uniwersytet Śląski. Wydział Informatyki i Nauki o Materiałach. Instytut Informatyki. Zakład Systemów Komputerowych
Tematy:: analiza składowych niezależnych
projekcyjne filtrowanie
EKG płodu
monitoring płodu
ciąża bliźniacza
independent component analysis
projective filtering
fetal ECG
fetal monitoring
twin pregnancy
Opis:: A combined application of independent component analysis and projective filtering of the time-aligned ECG beats is proposed to solve the problem of fetal ECG extraction from multi-channel maternal abdominal electric signals. The developed method is employed to process the four-channel abdominal signals recorded during twin pregnancy. The signals are complicated mixtures of the maternal ECG, the ECGs of the fetal twins and noise of other origin. The independent component analysis cannot separate the respective signals, but the proposed combination of the methods allows to suppress the maternal ECG and when the level of noise is low it leads to an effective separation of the twins' signals.
Źródło:: Journal of Medical Informatics & Technologies; 2008, 12; 83-89
1642-6037
Pojawia się w:: Journal of Medical Informatics & Technologies
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Handling class label noise in medical pattern classification systems
Autorzy:: Sáez, J. A.
Krawczyk, B.
Woźniak, M.
Powiązania:: https://bibliotekanauki.pl/articles/333813.pdf
Data publikacji:: 2015
Wydawca:: Uniwersytet Śląski. Wydział Informatyki i Nauki o Materiałach. Instytut Informatyki. Zakład Systemów Komputerowych
Tematy:: machine learning
pattern classification
class noise
noise filtering
decision support systems
uczenie maszynowe
klasyfikacja wzorców
filtracja zakłóceń
filtracja szumów
systemy wspomagania decyzji
Opis:: Pattern classification systems play an important role in medical decision support. They allow to automatize and speed-up the data analysis process, while being able to handle complex and massive amounts of information and discover new knowledge. However, their quality is based on the classification models built, which require a training set. In supervised classification we must supply class labels to each training sample, which is usually done by domain experts or some automatic systems. As both of these approaches cannot be deemed as flawless, there is a chance that the dataset is corrupted by class noise. In such a situation, class labels are wrongly assigned to objects, which may negatively affect the classifier training process and impair the classification performance. In this contribution, we analyze the usefulness of existing tools to deal with class noise, known as noise filtering methods, in the context of medical pattern classification. The experiments carried out on several real-world medical datasets prove the importance of noise filtering as a pre-processing step and its beneficial influence on the obtained classification accuracy.
Źródło:: Journal of Medical Informatics & Technologies; 2015, 24; 123-130
1642-6037
Pojawia się w:: Journal of Medical Informatics & Technologies
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Direct assessment of the fetal heart rate from abdominal composite recordings
Autorzy:: Moslem, B.
Bazzi, O.
Khalaf, J.
Diab, M.O.
Powiązania:: https://bibliotekanauki.pl/articles/334031.pdf
Data publikacji:: 2013
Wydawca:: Uniwersytet Śląski. Wydział Informatyki i Nauki o Materiałach. Instytut Informatyki. Zakład Systemów Komputerowych
Tematy:: Fetal heart rate
FHR
Fetal Electrocardiogram
FECG
independent component analysis
ICA
adaptive filtering
tętno płodu
EKG płodu
analiza składowych niezależnych
filtrowanie adaptacyjne
Opis:: In respect to the main goal of our ongoing work for analyzing fetal electrocardiogram (FECG) signals for monitoring the health of the fetus, we investigate in this paper the possibility of extracting the fetal heart rate (FHR) directly from the abdominal composite recordings. Our proposed approach is based on a combination of Independent Component Analysis (ICA) and least mean square (LMS) adaptive filter. The FHR of the estimated FECG signal is finally compared to a reference value extracted from a FECG signal recorded by using a spiral electrode attached directly to the fetal scalp. The experimental results show that FHR can be successfully evaluated directly from the abdominal composite recordings without the need of using any external reference signal.
Źródło:: Journal of Medical Informatics & Technologies; 2013, 22; 143-149
1642-6037
Pojawia się w:: Journal of Medical Informatics & Technologies
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Projective filtering based on L1-norm PC
Autorzy:: Przybyła, T.
Wróbel, J.
Pander, T.
Czabański, R.
Jeżewski, J.
Matonia, A.
Powiązania:: https://bibliotekanauki.pl/articles/332906.pdf
Data publikacji:: 2013
Wydawca:: Uniwersytet Śląski. Wydział Informatyki i Nauki o Materiałach. Instytut Informatyki. Zakład Systemów Komputerowych
Tematy:: embedded space
projective filtering
nonlinear noise reduction
PCA
L1-norm PCA
przestrzeń osadzona
filtrowanie rzutowe
nieliniowa redukcja szumów
norma L1 PCA
Opis:: The paper presents a modification of nonlinear state-space projections (NSSP) method. The proposed approach deals with the sub-space estimation problem. In the original NSSP method, the principal component analysis (PCA) is used for the subspace determination. The classical PCA uses L2-norm. It is well known that the L2-norm is sensitive to outliers. Thus, in this paper the L1-norm PCA is proposed a subspace determination. In numerical experiments an analytic signal and real ECG signals are processed with the proposed method. The signals are contaminated with Gaussian distributed noise with different signal to noise ratio (SNR). Obtained results confirm the usefulness of the proposed modification.
Źródło:: Journal of Medical Informatics & Technologies; 2013, 22; 79-86
1642-6037
Pojawia się w:: Journal of Medical Informatics & Technologies
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 11.

Tytuł:: Separation of groups of free radicals from noised EPR spectrum using genetic algorithm and gradient method
Autorzy:: Bernas, M.
Ramos, P.
Powiązania:: https://bibliotekanauki.pl/articles/951652.pdf
Data publikacji:: 2013
Wydawca:: Uniwersytet Śląski. Wydział Informatyki i Nauki o Materiałach. Instytut Informatyki. Zakład Systemów Komputerowych
Tematy:: signal filtering
genetic algorithms
spectra analysis
free radicals
EPR spectroscopy
function approximation
filtrowanie sygnału
algorytmy genetyczne
analiza widma
wolne rodniki
spektroskopia EPR
aproksymacja funkcji
Opis:: Different groups of free radicals exist in biological material like animal tissues or plants parts. The processes like heating or cooling creates additional types of free radicals groups in this organic matter, due to changes in chemical bonds. The paper proposes a method to determine types and concentrations of different groups of free radicals in the matter processed in various temperatures. The method extracts the spectrum of free radicals using electron paramagnetic resonance with the microwave power of 2.2 mW. Then an automatic method to find a best possible fit using limited number of theoretical mathematical functions is proposed. The match is found using spectrum filtration, and a genetic algorithm implementation supported by a Gradient Method. The obtained results were compared against the samples prepared by an expert. Finally, some remarks were given and new possibilities for future research were proposed.
Źródło:: Journal of Medical Informatics & Technologies; 2013, 22; 117-123
1642-6037
Pojawia się w:: Journal of Medical Informatics & Technologies
Dostawca treści:: Biblioteka Nauki

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