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Accurate estimation of seismic wavelet is very important to high-resolution, high-signal-noise ratio and high fidelity petroleum exploration and production data procession. As we known, the underground strata information changes as the depth changes. So it is a time-varying system. Obviously, it's not accurate enough to describe it with the linear time-invariant system. Fractional Fourier transform...
With the demand of image quality, a novel algorithm named MW-SVM is proposed for the enhancement of digital images based on mathematical morphology, watershed algorithm and SVM to remove noises and increase articulation. The MW-SVM algorithm is adopted in embedded network video monitoring system to improve video image quality. Firstly, the principle of MW-SVM algorithm and the structure of network...
It is possible to carry out PD location using the time difference of PD pulses received by a UHF antenna array. In practical applications, the electromagnetic interference within the substation will pollute these received signals and make it difficult to calculate the time difference of the PD pulses, which, thus, reduces the reliability of the PD source locating. Based on the segmented processing...
Because of its favorable corona resistant ability, ultra high-frequency (UHF) technique based partial discharge (PD) detection is widely applied in partial discharge detection of such power equipment as power transformer and gas insulated switchgear (GIS). However, in complicated electromagnetic environment of the substation, a great variety of UHF interference signals caused by communication such...
Noise in water is very crtical and may destroy the the OFDM based underwater acoustic communication system. The performance of pilot tones based channel estimation will not be the good choice under low SNRs. Complete frequency response of data channel is usually obtained by interpolating channel frequency response at pilot bits, such that the error of interpolation influences and degrades the performance...
Impulse voltage tests are essential to inspect and test insulation integrity of high voltage apparatus. On the other hand, generated impulse currents are used for different test applications such as investigation of high current effects, electromagnetic interference (EMI) testing, etc. Obtained voltage and current waveforms usually have some sort of interferences originated from the different sources...
Motion segmentation is an important research field as it forms the stepping stone for traffic monitoring, video surveillance, activity analysis, gait recognition and many other automatic imaging applications. In this work, a novel generic multiresolution (MR) based framework has been proposed in conjunction with Sigma-delta based motion segmentation algorithm. The framework provides a general platform...
With the higher demands for qualities of random sequences, true random sequences are paid more attention because of their higher security features. Although true random sequences have the character of unprediction, they still have problems on big deviation and correlation. The problem on how to get rid of these factors affecting security and obtain good randomicity is becoming the research focus....
This paper combined wavelet transform with extended kalman algorithm. By using wavelet transform which has characteristics of multiresolution to decompose the signal of ECG and then to filter the signal of ECG in each scale. Finally a decision rule is used to determine the QRS wave. The QRS detector has an average sensitivity of Se = 99.34% and a positive predictivity P+= 99.28% by evaluating the...
Aiming to the ECG signal including the noise such as the baseline drift, power frequency interference, and muscle power interference, etc, it is not easy to diagnose the patient's illness condition, so, the wavelet de-noising algorithm used in ECG signal is research in detail. This paper studied the wavelet multi-resolution decomposition and de-noising methods, as well as analyzes the way of the threshold...
Because of impurities, such as soil, hydrate, sour gas and so on, and corrosion during the pipeline operation, pigging is necessary. Spherical pig may be blocked in the pipeline. This paper briefly describes two positioning methods, which are based on wavelet transform method and pressure wave. Positioning principle, improved method and example are given. Compared with the actual value, the simulated...
In relation to the problems of time variability and the complexity of mine earthquake signal while blasting mining, a kind of wavelet soft threshold filter method is proposed. In this paper, the signal before mine earthquake wave arrival time is considered as noise, and is used to determine the wavelet threshold. Then Db4 wavelet is chosen as the wavelet basis function for the wavelet soft threshold...
The electrocardiogram (ECG) signals not only provide effective diagnosis support information for physicians, but also receive growing attention in areas of human identity recognition as a new kind of biomedical signals. An improved method for ECG feature point detection based on wavelet transform has been proposed in this paper. First, the ECG signal is pre-processed to remove noises and base-line...
The error in the initial attitude determination is one of the most crucial sources of error for accurate inertial navigation. Estimation of the initial attitude angles accurately is the guarantee of precise determination of the position, velocity and attitude of a moving platform. For military aircrafts, the high precision and short time of initial alignment are key requirements. The required inertial...
In automatic X-ray inspection, to denoise and enhance characteristics is a very important issue for application, especially the images used to inspect the wires in chips. Because the methods used to enhance or denoise may degrade the characteristic of the wires which can be seen as curves such that the efficiency is not enough. Shearlet has been approved of its perfect performance on curve description...
The traditional wavelet edge detection algorithm doesn't ideal processing effects for the salt & pepper noised images. In allusion to this shortcoming, an improved wavelet multi-scale edge detection algorithm is proposed in this paper. Morphology is assimilated into the wavelet detection, and an objective data evaluation is given. Compared with the traditional method, the related coefficient of...
In detection and localization of leakage from pipeline, as the signal of pressure is usually mixed with noise, the singularity of the negative pressure wave generated by a small leakage can not be accurately extracted by using conventional methods and thus the leakage can not be accurately located. For the above reasons, a practical method based on improved harmonic wavelet was used. This method is...
Synthetic Aperture Radar (SAR) satellite sensors recently provide valuable sources of earth observation data for various environmental applications. Beside the specifics properties of these data including multi-polarization and polarimetric image data, the presence of unavoidable speckle seriously degrades the quality of these data. Specifically, in certain applications such as clustering, classification...
Noise estimation is the important premise for image denoising. Recently, a noise estimation method based on the scale invariance assumption of high order statistics of natural images' filter response has been proposed and achieved performance superior to classic algorithms. However, in our research, we notice that the scale invariance assumption may not hold well for images with highly directional...
Ability to measure the surface quality in real-time has many applications in manufacturing automation and product optimization, especially in processes in which the surface qualities such as roughness, grain size, thickness of coding, impurities size and distribution, hardness, and other mechanical properties are of importance. Surface analysis in manufacturing environments requires specialized filtering...
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