11,875 research outputs found
Rehaussement du signal de parole par EMD et opérateur de Teager-Kaiser
The authors would like to thank Professor Mohamed Bahoura from Universite de Quebec a Rimouski for fruitful discussions on time adaptive thresholdingIn this paper a speech denoising strategy based on time adaptive thresholding of intrinsic modes functions (IMFs) of the signal, extracted by empirical mode decomposition (EMD), is introduced. The denoised signal is reconstructed by the superposition of its adaptive thresholded IMFs. Adaptive thresholds are estimated using the Teager–Kaiser energy operator (TKEO) of signal IMFs. More precisely, TKEO identifies the type of frame by expanding differences between speech and non-speech frames in each IMF. Based on the EMD, the proposed speech denoising scheme is a fully data-driven approach. The method is tested on speech signals with different noise levels and the results are compared to EMD-shrinkage and wavelet transform (WT) coupled with TKEO. Speech enhancement performance is evaluated using output signal to noise ratio (SNR) and perceptual evaluation of speech quality (PESQ) measure. Based on the analyzed speech signals, the proposed enhancement scheme performs better than WT-TKEO and EMD-shrinkage approaches in terms of output SNR and PESQ. The noise is greatly reduced using time-adaptive thresholding than universal thresholding. The study is limited to signals corrupted by additive white Gaussian noise
Gray Image extraction using Fuzzy Logic
Fuzzy systems concern fundamental methodology to represent and process
uncertainty and imprecision in the linguistic information. The fuzzy systems
that use fuzzy rules to represent the domain knowledge of the problem are known
as Fuzzy Rule Base Systems (FRBS). On the other hand image segmentation and
subsequent extraction from a noise-affected background, with the help of
various soft computing methods, are relatively new and quite popular due to
various reasons. These methods include various Artificial Neural Network (ANN)
models (primarily supervised in nature), Genetic Algorithm (GA) based
techniques, intensity histogram based methods etc. providing an extraction
solution working in unsupervised mode happens to be even more interesting
problem. Literature suggests that effort in this respect appears to be quite
rudimentary. In the present article, we propose a fuzzy rule guided novel
technique that is functional devoid of any external intervention during
execution. Experimental results suggest that this approach is an efficient one
in comparison to different other techniques extensively addressed in
literature. In order to justify the supremacy of performance of our proposed
technique in respect of its competitors, we take recourse to effective metrics
like Mean Squared Error (MSE), Mean Absolute Error (MAE), Peak Signal to Noise
Ratio (PSNR).Comment: 8 pages, 5 figures, Fuzzy Rule Base, Image Extraction, Fuzzy
Inference System (FIS), Membership Functions, Membership values,Image coding
and Processing, Soft Computing, Computer Vision Accepted and published in
IEEE. arXiv admin note: text overlap with arXiv:1206.363
Locally Adaptive Block Thresholding Method with Continuity Constraint
We present an algorithm that enables one to perform locally adaptive block
thresholding, while maintaining image continuity. Images are divided into
sub-images based some standard image attributes and thresholding technique is
employed over the sub-images. The present algorithm makes use of the thresholds
of neighboring sub-images to calculate a range of values. The image continuity
is taken care by choosing the threshold of the sub-image under consideration to
lie within the above range. After examining the average range values for
various sub-image sizes of a variety of images, it was found that the range of
acceptable threshold values is substantially high, justifying our assumption of
exploiting the freedom of range for bringing out local details.Comment: 12 Pages, 4 figures, 1 Tabl
Improvement of BM3D Algorithm and Employment to Satellite and CFA Images Denoising
This paper proposes a new procedure in order to improve the performance of
block matching and 3-D filtering (BM3D) image denoising algorithm. It is
demonstrated that it is possible to achieve a better performance than that of
BM3D algorithm in a variety of noise levels. This method changes BM3D algorithm
parameter values according to noise level, removes prefiltering, which is used
in high noise level; therefore Peak Signal-to-Noise Ratio (PSNR) and visual
quality get improved, and BM3D complexities and processing time are reduced.
This improved BM3D algorithm is extended and used to denoise satellite and
color filter array (CFA) images. Output results show that the performance has
upgraded in comparison with current methods of denoising satellite and CFA
images. In this regard this algorithm is compared with Adaptive PCA algorithm,
that has led to superior performance for denoising CFA images, on the subject
of PSNR and visual quality. Also the processing time has decreased
significantly.Comment: 11 pages, 7 figur
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