Basic Processing Operations Research Articles

Gifa V. 4: A complete package for NMR data set processing

The Gifa program is designed for processing, displaying and analysing 1D, 2D and 3D NMR data sets. It has been constructed in a modular fashion, based on three independent modules: a set of commands that perform all the basic processing operations such as apodisation functions, a complete set of Fourier Transforms, phasing and baseline correction, peak-picking and line fitting, linear prediction and maximum entropy processing; a set of command language primitives that permit the execution of complex macro commands; and a set of graphic commands that permit to build a complete graphic user interface, allowing the user to interact easily with the program. We have tried to create a versatile program that can be easily extended according to the user's requirements and that is adapted to a novice as well as an experienced user. The program runs on any UNIX computer, with or without graphic display, in interactive or batch mode.

Transfer function of spatial frequencies in parametric image amplification: experimental analysis and application to picosecond spatial filtering

We recently performed the parametric amplification of a monochromatic near-infrared image, in a KTP crystal with a resolution of 60 × 80 points and a gain of 15 dB. In this paper, we directly measure the transfer function of spatial frequencies by recording the image Fourier plane. This analysis confirms the link between the phase-matching conditions and the resolution. Moreover, parametric amplification can act either as a low pass filter or as a band-pass filter, depending of the orientation of the crystal. Consequently, basic image processing operation can be performed.

Exploitation of spectral redundancy in cyclostationary signals

It is shown that the cyclostationarity attribute, as it is reflected in the periodicities of (second-order) moments of the signal, can be interpreted in terms of the property that allows generation of spectral lines from the signal by putting it through a (quadratic) nonlinear transformation. The fundamental link between the spectral-line generation property and the statistical property called spectral correlation, which corresponds to the correlation that exists between the random fluctuations of components of the signal residing in distinct spectral bands, is explained. The effects on the spectral-correlation characteristics of some basic signal processing operations, such as filtering, product modulation, and time sampling, are examined. It is shown how to use these results to derive the spectral-correlation characteristics for various types of man-made signals. Some ways of exploiting the inherent spectral redundancy associated with spectral correlation to perform various signal processing tasks involving detection and estimation of highly corrupted man-made signals are described. >

Two-dimensional spatial light modulators: a tutorial

Two-dimensional spatial light modulators (SLMs) modulate one of the properties of an optical wavefront (amplitude, phase, polarization) as a function of two spatial dimensions and time in response to information-bearing control signals that may be either optical or electrical. These devices form a critical part of optical information processing systems, serving as input transducers as well as performing several basic processing operations on optical wavefronts. A tutorial overview of the 2-D SLMs is given. their applications are outlined, a classification scheme for them is given, and major types of SLMs that are under active development are described.

Interactive segmentation and boundary surface formation for 3-D digital images

In visualizing objects in 3-D digital images based on shaded-surface displays, segmentation of the 3-D regions is a basic processing operation. When object and nonobject regions touch or overlap and have identical features, automatic segmentation methods fail. We present an interactive technique which permits isolation of arbitrary subregions of the 3-D image by a region filling procedure. We illustrate the usefulness of this capability, through computerized tomography data, in preoperative surgical planning and for producing arbitrary fragmentations of objects in 3-D images. The techniques are applicable in other fields as well, where independent display of overlapping structures is important. When the object regions are specified through a set of contours in a sequence of slices, we show that the boundary surfaces of the object are produceable in an efficient way using the cuberille-based discrete representation of the object surfaces. The algorithms we present for forming boundary surfaces do not impose restrictions on the shape and pattern of distribution of contours in the slices as do the surface tiling schemes reported in the literature. We assume that a contour is made up of at least three points.

A graph theoretic formulation of bit pattern algorithms for graphics

A graph theoretic formulation of bit pattern algorithms for computer graphics is presented. A two-dimensional N×N bit array, called the canvas memory, is used to formulate the concepts of domain, boundary curve, and scanning, which are used to describe basic picture processing algorithms such as scan conversion, domain partitioning, inclusion test, scissoring, and cross point detection. the basis of the formulation is given in terms of point set, cycle in dual graph, and pseudo-Hamiltonian path. Except for the computational time complexity of scan conversion, which is inherently quadratic, O(N2), in terms of the resolution N, linear (O(N)) algorithms for all the other basic picture processing operations are presented.

Fixation Point Measurement by the Oculometer Technique

In this paper, we describe an Oculometer which is an electro-optical device that measures eye direction (and fixation point coordinates) without attachment to, or clamping of, the subject. By virtue of its special optical characteristics, the same basic system can be configured for operation very close to the subject, as in a head mounted system, and also at a distance of several feet or more from the subject. The basic signal processing operation is the same for all configurations, and is performed by a standard minicomputer. It is also shown that additional signal processing, as required in certain configurations and applications, can be added as a separate software module to the general Oculometer software.

Complex pedogenesis of ferrallitic savanna soils in South Sudan

Complex pedogenesis in ferrallitic savanna soils is demonstrated by means of three typical profiles. The information provided includes relative age relationship of soils on the polycyclic pediment slopes, macro- and micromorphological characteristics, some chemical and complete mineralogical data. The authors compare the operation of basic processes of saprolitization (kaolinization, primary mottling) and pedogenesis (homogenization, local, vertical and lateral redistribution of iron) in forest soils formed on deep saprolite, and savanna soils on generally much shallower saprolite. Complex pedogenesis in the latter results from intermittent erosional impact, changes of climate and the stepwise downward weathering and deepening of the solum. All of these factors cause (homo- or heterogenetic) changes of internal hydrological conditions in the whole or parts of the solum. By means of detailed differentiation of ferruginous precipitates in regard to their crystal form (hematite and goethite) and their successive formation and alteration, the authors attempt to elucidate the history of soil formation.

AUTOMATIC SYNTHESIS OF CONTROLSTEPS IN BATCH PROCESS OPERATIONS

In general, a batch chemical plant is used to produce multiple products and its key characteristics is flexibility. The flexibility means that the same processing equipment units may be employed to produce different products or the same product may be produced in different processing equipment units. In order to produce a desired product, the processing requirements specified in the product recipe must be converted to a set of control steps or operating procedures. In practice, this kind of tedious and time-consuming work is done by the process engineers based on their experience. A three-step synthesis strategy for the automatic synthesis of control steps in batch process operations is presented in this paper. The first step is pre-operation which consists of a set of process operation checks, safety checks as well as user-specific checks that must be considered before the starting of the basic process operation. The second step is operation which is described by a set of basic control steps such as open valve and start pump. The third step is post-operation which is described by a set of instructions that must be performed when the basic process operation is terminated. The emphasis is how to perform the required basic process operations in the specified processing equipment units. In this strategy, object-oriented programming (OOP) is used to represent the processing equipment units and the master recipe procedures. The plant topology and the processing equipment units are represented by a process matrix, and the processing requirements are represented by a master recipe which is converted from a general recipe. The three-step synthesis strategy has been implemented as part of a recipe management system. These control steps may be passed to the control engineer or a control computer for the generation of the control code.

On the Detection of a Known Signal in a Non-Gaussian Noise Process

In this paper, three receiver designs for the detection of a known signal in an additive non-Gaussian noise process are considered. The noise process consists of white Gaussian noise modulated by a random-spectrum level. The first receiver considered is an optimum (likelihood) processor and the remaining two receivers are suboptimum designs consisting of a cross correlator and a likelihood correlator. The basic processing operations of the three receivers are investigated and compared on the basis of their effects in observation space. The performance of each receiver is evaluated and presented in terms of ROC curves. A comparison of the performance curves indicates a loss in optimum performance as compared to the Gaussian noise case and a significant loss in performance of the suboptimum receivers relative to the optimum receiver.

Bulk Processing in Distributed Logic Memory

Use of a content-addressable memory as a highly parallel digital computer is described. The ability to perform any arithmetic operation on many sets of data at the same time is shown. The memory organization and the storage of data are such that many operations are performed parallel by bit as well as parallel by word, resulting in more efficient algorithms and shorter execution times. Consideration of the limitations of a linear memory array in performing such operations leads to the description of a more efficient organization, called the two-dimensional distributed logic memory. The efficiency of this form in the bulk processing of data is illustrated by a number of algorithms for basic data processing operations, including matrix inversion.