Special issue on microscopic image processing

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Interframe differential coding of line spectrum frequencies

Cataloged from PDF version of article.Line spectrum frequencies (LSF's) uniquely represent the linear predictive coding (LPC) filter of a speech frame. In many vocoders LSF's are used to encode the LPC parameters. In this paper, an inter-frame differential coding scheme is presented for the LSF's. The LSF's of the current speech frame are predicted by using both the LSF's of the previous frame and some of the LSF's of the current frame. Then, the difference resulting from prediction is quantized

A low complexity DSP driven analog impairment mitigation scheme for low-IF GNSS receivers

Due to the increasing demands for location based services within the wireless mass-market; there has been relentless pressure to reduce both the chip area and power dissipation of the user terminal. Low-IF receivers combine the advantages of superheterodyne and direct-conversion architectures offering a highly integrated solution while avoiding the issues associated with DC offsets and flicker noise. The main drawback of the low-IF architecture is its limited image rejection due to analog impairments. In this paper, the sources of the impairments are analyzed for a low-IF receiver operating at the GPS/Galileo L1 band together with a novel low-complexity solution to compensate for them in the DSP domain is proposed. For processing the combined GPS/Galileo L1 signal, a signal simulator we call GNSScope has been developed together with a low-IF receiver model to analyze the influence of the analog impairments. The idea behind our proposed novel adaptive compensator which estimates and compensates for the imbalances and mismatches is that in the absence of these mismatches no correlation exists between the desired and the image channels, which is not the case when impairments are present. Results show that through the deployment of the proposed approach, image-rejection performance can be enhanced by 75 dB. This enhancement in the image-rejection performance subsequently results in relaxed analog front-end specifications leading to high levels of integration making it possible for highly integrated software-defined Global Navigation Satellite Systems (GNSS) receiver to be realistically and economically designed and implemented

With four Standard Model families, the LHC could discover the Higgs boson with a few fb^-1

The existence of a 4th SM family would produce a large enhancement of the gluon fusion channel of Higgs boson production at hadron colliders. In this case, the SM Higgs boson could be seen at the CERN Large Hadron Collider (LHC) via the golden mode (H->4l) with an integral luminosity of only a few fb^-1.Comment: 7 pages, 2 figures, 2 tables, references updated in v

Signal recovery from wavelet transform maxima

Cataloged from PDF version of article.This paper presents an iterative algorithm for signal recovery from discrete-time wavelet transform maxima. The signal recovery algorithm is developed by using the method of projections onto convex sets. Convergence of the algorithm is assured

Special Issue on dynamic textures in video

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Content-based video copy detection based on motion vectors estimated using a lower frame rate

Cataloged from PDF version of article.We propose a motion vector based Video Content Based Copy Detection (VCBCD) method. One of the signatures of a given video is motion vectors extracted from image sequences. However, when consecutive image frames are used they are not descriptive enough because most vectors are either too small or they appear to scatter in all directions. We calculate motion vectors in a lower frame rate than the actual frame rate of the video to overcome this problem. As a result we obtain large vectors and they represent a given video in a robust manner. We carry out experiments for various parameters and present the results

Cross-Term-Free Time-Frequency Distribution Reconstruction via Lifted Projections

Cataloged from PDF version of article.A crucial aspect of time-frequency (TF) analysis is the identification of separate components in a multicomponent signal. The Wigner-Ville distribution is the classical tool for representing such signals, but it suffers from cross-terms. Other methods, which are members of Cohen's class of distributions, also aim to remove the cross-terms by masking the ambiguity function (AF), but they result in reduced resolution. Most practical time-varying signals are in the form of weighted trajectories on the TF plane, and many others are sparse in nature. Therefore, in recent studies the problem is cast as TF distribution reconstruction using a subset of AF domain coefficients and sparsity assumption. Sparsity can be achieved by constraining or minimizing the l(1) norm. In this article, an l(1) minimization approach based on projections onto convex sets is proposed to obtain a high-resolution, cross-term-free TF distribution for a given signal. The new method does not require any parameter adjustment to obtain a solution. Experimental results are presented

Moving Shadow Detection in Video Using Cepstrum

Cataloged from PDF version of article.Moving shadows constitute problems in various applications such as image segmentation and object tracking. The main cause of these problems is the misclassification of the shadow pixels as target pixels. Therefore, the use of an accurate and reliable shadow detection method is essential to realize intelligent video processing applications. In this paper, a cepstrum-based method for moving shadow detection is presented. The proposed method is tested on outdoor and indoor video sequences using well-known benchmark test sets. To show the improvements over previous approaches, quantitative metrics are introduced and comparisons based on these metrics are made