Suitable Quantization Research Articles

The lossless compression of AVIRIS images by vector quantization

The structure of hyperspectral images reveals spectral responses that would seem ideal candidates for compression by vector quantization. This paper outlines the results of an investigation of lossless vector quantization of 224-band Airborne/Visible Infrared imaging Spectrometer (AVIRIS) images. Various vector formation techniques are identified and suitable quantization parameters are investigated. A new technique, mean-normalized vector quantization (M-NVQ), is proposed which produces compression performances approaching the theoretical minimum compressed image entropy of 5 bits/pixel. Images are compressed from original image entropies of between 8.28 and 10.89 bits/pixel to between 4.83 and 5.90 bits/pixel.

Signal reconstruction from partial data for sensor array imaging applications

In this paper, the problem of signal recovery from partial information with special reference to sensor array imaging situations is examined. In sensor array imaging, as used for viewing underwater objects, the complex wave field is measured at a discrete set of points on a receiver airier. This data is used to reconstruct an image of the object using a suitable transformation. This data can be viewed as partial magnitude and phase data, which after appropriate phase modification, is transformed to obtain the object information. Recently, algorithms have been proposed in the literature for reconstruction of signals from partial information such as magnitude or phase (1-bit phase in some cases) of the Fourier transform. We examine the relevance of these algorithms to sensor array imaging situations. We propose new algorithms that are applicable to these situations. In particular, we show that measurement at multiple frequencies with suitable phase quantization reduces the receiver complexity and sometimes the effects of noise. The proposed new algorithms are demonstrated with several illustrations of simulated field data for a simplified model of an imaging setup.

Analysis of Collective-Noncollective Couplings in a Degenerate Many j-Shell Model

The selfconsistent-collective-coordinate method is applied to anharmonic quadrupole vibrations in a degenerate many j-shell model with the pairing-plus-quadrupole force. By comparing the result obtained by this method with that obtained by the boson-expansion method, it is shown that 1) the selfconsistent-collective-coordinate method yields, after a suitable canonical quantization, the result that agrees to order (j + 1/2)-1 with that obtained by the boson-expansion method, in the limit that the time-dependent Hartree-Bogoliubov space is truncated to the multiphonon space built out of the 2+ phonons, and 2) the couplings between the RPA 2+ phonons and the other modes (the pairing rotations and the noncollective modes) considerably modify the fourth-order boson Hamiltonian obtained by the conventional boson-expansion method.

Activity function for DCT coded images

By combining a measure of activity in transform-coded image blocks with frequency sensitivity data, suitable psychovisual coefficient quantisation step sizes can be calculated. A number of possible definitions for an activity function AT are proposed. The most suitable of these is determined by comparing results on a subjective basis.

Tomonaga-Dirac-Schwinger formulation of the fermionic string

We present the Tomonaga-Dirac-Schwinger formulation of the fermionic string. The constraint algebra of the classical theory reproduces upon suitable quantization the superconformal algebra of the BRST formalism. The supergeometrodynamic degrees of freedom are related to the ghost and superghost variables in a simple manner.

Canonical structure of the CPn−12 model in some noncovariant gauges

The canonical structure of the CPn−12 model is derived in four different noncovariant gauges using the Dirac method for constrained Lagrangian systems. A suitable quantization scheme is proposed for all n.

Field-theoretical space-time quantisation

Using the framework of the quantum field theory it is proved that the possibility exists of performing—within binary description formalism—a suitable space-time quantisation. In this respect the mutual connection between the action quantisation and the space-time quantisation has been established.

A class of codes for polyphase signals on a bandlimited Gaussian channel

A new class of codes is defined and analyzed when applied to a communication system that sends data over a bandlimited Gaussian channel. A code word is defined as a sequence of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</tex> -phase values and transmitted either modulated on a carrier or transformed into <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n = 2r</tex> samples on a baseband channel. An algebraic procedure is used to generate the phase sequence from a set of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p</tex> equidistant angles. The baseband model is analyzed in detail and the performance is evaluated by first assuming an ideal detector and computing an error-probability bound. Taking <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p = 61,73</tex> , and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">97</tex> , codes are shown to exist that perform close to the theoretical limit. The algebraic structure of these codes much simplifies the numerical analysis. A second receiver is defined that extracts phase values out of the received waveform and then performs a suitable quantization. The degradation of this detector appears to be moderate for low information rates when evaluated for <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p = 61</tex> . A carrier phase-modulated system is also defined and evaluated with a performance quite similar to the baseband model.