Periodic noises are unwished and spurious signals that create repetitive pattern on images and decreased the visual quality. Firstly, this paper investigates various methods for reducing the effects of the periodic noise in digital images. Then an adaptive optimum notch filter is proposed. In the proposed method, the regions of noise frequencies are determined by analyzing the spectral of noisy...

In recent years, active filters have been considered and developed for elimation of harmonics in power networks. Comparing with passive, they are smaller and have better compensating characteristics and resistance to line distortions. In this paper, a novel idea based on adaptive filter theory in presented to develop an active filter to eliminate the distortions of an arbitrary signal. Using th...

Recently it has been shown that principal component filter banks (PCFB) are optimum orthonormal filter banks for subband coding for the uniform case in which all decimation ratios are the same. In this paper we present the analogous results for the nonuniform case. In contrast to the uniform case where there is only one PCFB, there are more than one PCFB’s in the nonuniform case. For a fixed se...

A multi-dimensional variable-length subband coder for prestack seismic data was presented. A 2and 3-D separable near perfect reconstruction filter bank was optimized to maximize the coding gain, assuming that the correlation properties of pre-stack seismic data can be modeled by directional dependent autoregressive processes. Identical quantization and entropy coder allocation strategies were u...

Subband decomposition of HDTV signals is important both for representation purposes (to create compatible subchannels) and for coding (several proposed compression schemes include some subband division). We first review perfect reconstruction filter banks in multiple dimensions in the context of arbitrary sampling patterns. Then we concentrate on the special case of quincunx subsampling and der...

We have recently made explicit the precise connection between the optimization of orthonormal filter banks (FBs) and the principal component property: The principal component filter bank (PCFB) is optimal whenever the minimization objective is a concave function of the subband variances of the FB. This explains PCFB optimality for compression, progressive transmission, and various hitherto unno...

Abstract: The SBC (subband coding) using the multirate filter bank was proposed in 1980, this coding method splits full audio spectrum into subbands, and assigns more bits to each subband with higher energy. If the power spectral density (PSD) of any subbands is approximately zero, then those subbands need not be assigned any bits at all. While reconstruction, the subband signals are synthesize...

In the contourlet transform (CT), the Laplacian pyramid (LP) decomposes an image into a low-frequency (LF) subband and a high-frequency (HF) subband. The LF subband is created by filtering the original image with 2-D low-pass filter. However, the HF subband is created by subtracting the synthesized LF subband from the original image but not by 2-D high-pass filtering the original image. In this...

The major goal of a noise reduction algorithm for hearing aid applications is to improve speech intelligibility. In [1], a multichannel noise reduction technique, based on a Generalized Singular Value Decomposition (GSVD) has been proposed. The GSVD based filter minimizes the Mean Square Error (MSE) between the desired signal portion in the received signals and a filtered sum of the received mi...