In this paper we propose an adaptive image restoration algorithm using block-based edge-classi"cation for reducing block artifacts in compressed images. In order to e$ciently reduce block artifacts, edge direction of each block is classi"ed by using model-"tting criterion, and the constrained least-squares (CLS) "lter with corresponding direction is used for restoring the block. The proposed re...

This paper describes a method for designing a lter bank for segmenting modulation features in line textures. A new version of the S-Gabor lter of Heitger et al 1] is developed in which the range of frequencies covered by the lter can be easily controlled. A method of tuning S-Gabor lters to modulation features in line textures is also presented. The candidate frequency set is obtained by select...

Robust source coding provides both compression and noise mitigation without channel coding. In this paper , two methods of robust source coding are presented. The rst is DPCM incorporating a nonlinear lter; the second is Predictive Trellis-Coded Quantiza-tion (PTCQ), whose prediction lter is also nonlinear. Findings show that the incorporation of the nonlinear lter provides the ability to conce...

A lter is a system that can be used to modify or reshape the frequency spectrum of a signal according to some prescribed requirements. Generally, the purpose of most lters is to separate the desired signals from undesired signals or noise. A digital lter takes an input sequence of numbers and produces an output sequence of numbers. The lter design is a set of processes, that starts with the spe...

Collaboration between ecologists and learning scientists can give rise to powerful models for scientific outreach within ecology. This paper presents a process by which codesigned science curriculum that invites students join an ecological community of practice. In the Journey El Yunque middle school curriculum, engage with simulation generated from data gathered Luquillo Long Term Ecological R...

The preceding design methods have been based on designing an analog prototype lter and then converting it to a digital lter. This approach is appropriate for the class of approximations where analytical solutions are possible, but not for many others. In the remaining part of this chapter, methods will be developed that directly design the desired digital lter. Most approaches are extensions of...

We design lter banks that are best matched to input signal statistics in M-channel sub-band coders, using a rate{distortion criterion. Recent research has shown that unconstrained{ length paraunitary lter banks optimized under various energy compaction criteria are principal-component lter banks and satisfy two fundamental properties: total decorrelation and spectral majorization. We present se...

Line integral convolution (LIC) has become a well-known and popular method for visualizing vector elds. The method works by convolving a random input texture along the integral curves of the vector eld. In order to accelerate image synthesis signiicantly, an eecient algorithm has been proposed that utilizes pixel coherence in eld line direction. This algorithm, called \fast LIC", originally was...

The large eddy simulation (LES) equations of turbulent ows are formally derived by applying a low-pass lter to the Navier-Stokes equations. As a result the subgrid-scale (SGS) stress tensor strongly depends on the assumed lter shape, which causes an SGS model to be lter dependent. In particular, depending on the choice of the lter the corresponding SGS model should satisfy very diierent require...

This paper introduces a new scheme for the numerical computation involving shock waves. The essence of the scheme is to adaptively implement a conjugate low-pass lter to e ectively remove the accumulated numerical errors produced by a set of high-pass lters. The advantages of using such an adaptive algorithm are its controllable accuracy, relatively low cost and easy implementation. Numerical e...