In the subband coding of images, directionality of image features has thus far been exploited very little. The proposed subband coding scheme utilizes orientation of local image features to avoid the highly objectionable Gibbs-like phenomena observed at reconstructed image edges with conventional subband schemes at low bit rates, At comparable bit rates, the subjective image quality obtained by...

We propose a subband spreading technique to average a frequency selective fading channel which produces different signal-to-noise ratios (SNR) per subcarrier in orthogonal frequency division multiplexing (OFDM) systems. Data symbols are spread over a subband using orthogonal codes and transmitted. Each subband is composed of a group of subcarriers. Received symbols in a subband have the same re...

In this paper, a novel entropy-based voice activity detection (VAD) algorithm is presented in variable-level noise environment. Since the frequency energy of different types of noise focuses on different frequency subband, the effect of corrupted noise on each frequency subband is different. It is found that the seriously obscured frequency subbands have little word signal information left, and...

A consistent theory of optimum subband coding of zero mean wide-sense cyclostationary signals with Nperiodic statistics is presented in this paper. Blocked polyphase representation of the analysis and synthesis filter banks is introduced as an effective way of multirate subband coder description. Optimum energy compaction using Nyquist-M process is presented as a solution for maximizing the cod...

To evaluate or compare the convergence speed of adaptive digital filters (ADF) with least mean squared (LMS) algorithm, the condition numbers of correlation matrices of tapinput vectors are often used. In this paper, however, the comparison of the conventional fullband ADF and the subband ADF based on their condition numbers is shown to be invalid. In some cases, the over-sampled subband ADF co...

this paper studies the use of unscented kalman filters (ukf) to estimate nonlinear dynamics and, specifically, adaptive determination of scaling parameters in these filters. due to lack of analytic solution and use of numerical methods instead, the computational load of these filters increases drastically. in this paper, a new method is proposed based on interactive multiple models (imm) which ...

The particle filter (PF) is a novel technique that has sufficiently good estimation results for the nonlinear/non-Gaussian systems. However, PF is inconsistent that caused mainly by loss of particle diversity in resampling step and unknown a priori knowledge of the noise statistics. This paper introduces a new modified particle filter called adaptive unscented particle filter (AUPF) to overcome th...

We employ a hybrid state-space sinusoidal model for general use in analysis-synthesis based audio transformations. This model, which has appeared previously in altered forms (e.g. [5], [8], perhaps others) combines the advantages of a source-filter model with the flexible, time-frequency based transformations of the sinusoidal model. For this paper, we specialize the parameter identification ta...

Wideband active noise control systems usually have hundreds of taps for control filters and the cancellation path models, which results in high computational complexity and low convergence speed. Several active noise control algorithms based on subband adaptive filtering have been developed to reduce the computational complexity and to increase the convergence speed. The subband structure is si...

This paper discusses the application of adaptive modulation and adaptive rate turbo coding to orthogonal frequency-division multiplexing (OFDM), to increase throughput on the time and frequency selective channel. The adaptive turbo code scheme is based on a subband adaptive method, and compares two adaptive systems: a conventional approach where a separate turbo code is used for each subband, a...