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High power electron beams are used for welding critical components in aerospace and nuclear industries due to their inherent advantages. There are high quality requirements in these industries and hence the associated cost of materials and processes is also very high. This makes it very important to ensure that the beam quality is maintained and checked prior to carrying out the welds. The processes...
This paper gives a method which bases on the wavelet decomposition and the neural network to predict the short-time load. Using wavelet transform, the load sequence is decomposed into sub-sequences on different scales, then using appropriate artificial neural network models the sub-sequences of forecasting date are predicted. Finally, by means of restructuring from the sub-sequences, the final forecasting...
Given the different transmission characteristics under the wavelet transform (WT) domain and the different distribution characteristics of frequency domain of the signal and noise, a novel approach for detecting laser radar target based on wavelet transform has been proposed. Usually, wavelet decomposition has been used to de-noise a digital signal corrupted by noise. In our approach, we applied the...
Using the characteristics of the chaotic system, such as ergodicity, sensitivity to initial condition, system parameters and random like behavior, this paper proposes a new image encryption algorithm based on chaotic sequences and wavelet transform. This algorithm controls the initial parameters of two one-dimensional chaotic sequences through keys, generates the chaotic sequence, diffuses the image,...
High-frequency stress wave analysis was used as characteristic parameter to detect the early stages of the loss of mechanical integrity in low-speed machinery in the paper. The background noise was eliminated using wavelet decomposition and the feature frequency of fault stress waves was extracted. Firstly, according to the characters of the fault stress waves obtained from a steel mill, db6 was selected...
According to the different transmission characteristics under the wavelet transform(WT) domain and the different distribution characteristics of frequency domain of the signal and noise, a novel approach for detecting weak signal laser radar target based on wavelet transform has been proposed. In many cases, wavelet decomposition has been used to de-noise a digital signal submerged by mass noise....
Based on wavelet transform (WT), this paper proposed an approach to extract ICESat/GLAS full waveform characteristics. Through wavelet decomposition of the full waveform data, setting the threshold function and reconstructing signal, the filtered waveforms were achieved. All comparisons were performed on simulated LiDAR full waveform signals with typical back scattering noise. In the simulation and...
According to the characteristics of fax paper, a method of content-based fax retrieval is put forward. The wavelet decomposition is used in the fax image de-noising, and the wavelet coefficients are used for regional division, and then combined with optical character recognition technology to extract the semantic features of the text region and the shape features of the logo for the fax retrieval...
Eye ball movements are vital signs in some of the neurological disorders and it can be tracked by acquiring electrooculogram (EOG) signals. EOG is an obtrusive, inexpensive and non-invasive means of recording eye ball movements. The source for EOG signal is cornea-retinal potential (CRP) and is generated due to the movements of eye balls within the conductive environment of the skull. While recording...
This paper presents a new wavelet domain watermarking method, the carrier image using wavelet decomposition. After the Walsh transform low frequency wavelet coefficients, calculated by block adaptive embedding strength, modify the wavelet coefficients of each block, and then do singular value decomposition (SVD), repeat on embedded watermark in the singular value. Fractional part of the anti-transformed...
This paper presents an intra-modal fusion environment to integrate multiple raw palm images at low level. Fusion of palmprint instances is performed by wavelet transform and decomposition. To capture the palm characteristics, fused image is convolved with Gabor wavelet transform. The Gabor wavelet feature representation reflects very high dimensional space. To reduce the high dimensionality, ant colony...
Based on the statistical properties of the colored noise in wavelet domain and the whitening property of wavelet transform, we present a novel method to filter colored noise efficiently. The proposed method treats every detail subband in wavelet domain as a regular image with white noise, and filters the noise using the threshold value algorithm by iteratively performing wavelet decomposition. The...
A new thresholding function is proposed for image denoising in the wavelet domain. The new threshold function has the same characteristic of continuity with the soft-thresholding function, and also overcomes the defects of constant bias between the estimate of the wavelet coefficients and wavelet decomposition in the soft-thresholding function, the thresholding function effects are considered simultaneously...
The key to surgical planning for breast conservation is tumor localization. An accurate localization of the breast tumor is essential to guide the surgeon to the lesion, and ensure its correct and adequate removal with satisfactory excision margins. Current breast tumor localization techniques are invasive and often result in a cosmetic disfigurement. In this paper, we use the ultrawide band radar-based...
Now the wavelet is an advanced tool in signal processing, and if there is no signal lost after decomposition, the reconstruction may be perfect and the reconstructed signal is almost the same as the original signal. But if some signal is lost after decomposition, then the lost signal need to be obtained before reconstruction to perform the perfect reconstruction. The idea of difference compare is...
The signal acquisition and processing of homogenizing pressure in high pressure homogenizer are studied. For the measuring requirements of dynamic parameters in high pressure homogenizer, pressure transmitter, the signal collecting circuits about intensifier pump's motion were selected. The signal acquisition system can perform the functions such as signal collecting, recording and data recalling...
The performance of wavelet-based multifocus image fusion depends on the number of decomposition levels in the wavelet transform. Too few decomposition levels result in poor spatial quality in the fused images. On the other hand, too many levels induce distortion between the original and the fused images. In general, fusion of images with larger resolution requires a higher number of decomposition...
To compensate for the deficiencies of traditional wavelet threshold shrinkage denoising algorithm and obtain the heart sounds with high SNR, an improved wavelet threshold shrinkage algorithm is proposed in this paper. The algorithm uses a new subband adaptive threshold and a new threshold function to quantify the detail coefficients of wavelet decomposition of noisy heart sounds, and its denoising...
The surface topography errors of micro electrical discharge machining (Micro-EDM) are mainly composed of surface roughness, surface waveness and profile error, which have influence on the workpiece's functions and performances in various degrees. Thus, how to pick up these errors without distortion is quite important for evaluating the surface topography. Further research shows that the frequency...
With the rapid development of modern society and technological progress, using a variety of human organs to identify the needs of growing, due to wavelet decomposition in the airspace and frequency domain can provide good local information, especially in the wavelet decomposition can be reduced the image resolution, and thus a corresponding reduction in computational complexity, the wavelet transform...
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