bluuebunny/crossref_metadata_2025 huggingface dataset:
In Situ Excimer Laser Irradiation of GaAs Surfaces During Schottky Barrier Formation*
Authors: Maki P.A. , Ehrlich D.J.
Published: February 2023

Schottky barrier heights of all metals deposited on GaAs are largely controlled by the inherent Fermi level pinning at the surface which appears with even submonolayer coverages of metals or oxygen. The measured electrical characteristics of Schottky diodes will also depend upon the homogeneity of the surface at the time of metallization. Variations in the relative surface areas of oxides and clean surface will result in variations in apparent barrier height and diode ideality.
Modulated Molecular Beam Studies of Semiconductor Etching
Authors: Olander D. R.
Published: February 2023

In commercial practice, single-crystal semiconductors are etched using reactive gases in plasma discharges. Rational design of such processes requires quantitative models of the kinetics of the surface reactions by which substrate atoms are removed as volatile species, usually fluorides or chlorides. Because of the complexity of plasma etching, single-effect experiments, in which only the chemistry of the surface reactions are investigated, are very useful.
Multiphoton-Induced Desorption of Positive Ions from Bariumfluoride
Authors: Matthias E. , Nielsen H.N. , Reif J. , Rosén A. , Westin E.
Published: February 2023

This paper is addressed to the question of surface states on the (111)-surface of BaF2, which can serve as a model for other divalent ionic crystals. The goal is to prove that surface states, which are energetically located in the middle and upper half of the bandgap, play a decisive role in the desorption process. They can either absorb single photons which results in local heating and thermal desorption or, more of interest in this context, they can resonantly enhance multiphoton absorption.
Low-Energy Ion Irradiation Effects During Nucleation and Film Growth.
Authors: Sundgren J.-E. , Greene J.E.
Published: February 2023

Low-energy (< 500 eV) particle bombardment during film growth from the vapor phase has been shown to play an important and sometimes dominant role in controlling the growth kinetics and hence microstructure and physical properties of films deposited by glow discharge and ion beam sputtering, molecular beam epitaxy (MBE) using accelerated dopants, and plasma-assisted chemical vapor deposition. Important ion/surface interaction effects include, trapping, preferential sputtering, collisional mixing, creation of preferential nucleation sites and enhancement of adatom mobilities. The effects which predominate during ion bombardment of the substrate and growing film depend primarily upon the energy, mass and flux of the projectiles, the substrate and film materials, orientation, and the film growth temperature.
Gold Deposition From an Organometallic Gas Induced by Incident Ga+, Ar+, or Si+ Ions*
Authors: Shedd G.M. , Lezec H. , Dubner A.D , Melngailis J.
Published: February 2023

If a local gas ambient of 10−3 to 10−2 torr pressure of a metal halide, organometallic, or hydrocarbon gas is produced at a surface, deposition of material can be induced where ions are incident. The ion beam is thought to cause the breakup of molecules adsorbed on the surface. Deposition of a mixture of Al, C, and O has been reported(1) from a gas of Al(CH3)3 and mixture of W and O from a gas of WF6. We have used a capillary gas feed of dimethyl gold hexafluoro acetylacetonate (C7H7F6O2Au) and induced gold deposition using a focused 15kV Ga+ ion beam or broad beams of 50kV Si+ and 0.75kV Ar+. See Fig. 1.
Laser probing of gas-surface interaction dynamics
Authors: Mödi A. , Budde F. , Gritsch T. , Chuang T. J. , Ertl G.
Published: February 2023

Collision of a molecule with a solid surface leads to energy redistribution within its translational as well as internal degrees of freedom. The populations of the various quantum states of the latter may be probed by laser induced fluorescence (LIF) or by multiphoton ionisation (MPI). Combination of these techniques with time-of-flight (TOF) measurements in a molecular beam apparatus allows, in addition, determination of state-selected translational energy distributions.
Sum Frequency Generation on Dye-Coated Surfaces Using Collinear and Non-collinear Excitation Geometries
Authors: Muenchausen Ross E. , Nguyen Dinh C. , Keller Richard A. , Nogar Nicholas S.
Published: February 2023

Second harmonic generation (SHG) with a collinear excitation geometry is becoming an important tool for surface studies [1]. Phase-matching on the surface is inherently satisfied since the nonlinear generation occurs over distances corresponding to only a few monolayers. We report resonantly enhanced sum frequency generation (SFG) for both collinear [2] and non-collinear [3] excitation geometries.
Optical Second Harmonic Generation Studies of Surface Adsorption and Segregation on Fe-18Cr-3Mo (110)*
Authors: Anderson R.J. , Hamilton J.C. , Foltz G.W.
Published: February 2023

Optical second harmonic generation (SHG) is a promising new surface-sensitive technique that allows study of electronic structure and surface ordering for submonolayer coverages of adsorbates at pressures not accessible using more conventional surface probes. Furthermore, SHG is well-suited to probing buried interfaces between a thin overlayer and a substrate. We report here recent studies of adsorption and segregation on clean single crystal Fe-18Cr-3Mo (110) surfaces in ultra-high vacuum using SHG, low energy electron diffraction (LEED), and Auger observations.
Tunneling Spectroscopy Study of Aniline Adsorbed on Aluminum Oxide
Authors: Graves R.J. , White H.W.
Published: February 2023

Information on the types and orientations of molecular species produced at the metal-adsorbate interface is generally very difficult to obtain since the thickness of the region is of the order of 5 to 10 angstroms. Tunneling spectroscopy can provide information on the bonding of these species and, to a limited extent, provide some information on their orientations with respect to the oxide.
The Role of F-Centers in Electron- and Photon-Stimulated Desorption from Alkali Halides
Authors: Loubriel G. M. , Green T. A. , Tolk N. H. , Haglund R. F.
Published: February 2023

Measurements of the time history of ground state neutral lithium desorption from LiF during pulsed irradiation have resulted in a new model for lithium desorption.
In-situ Ellipsometry During Thin Film Growth
Authors: Collins Robert W.
Published: February 2023

Applications of real time ellipsometry in elucidating the nucleation, growth, microstructural evolution, and surface modification of thin film hydrogenated amorphous silicon (a-Si:H)-based materials will be discussed. The reactive, high pressure environment of rf plasma-enhanced chemical vapor deposition (PECVD) and the disordered structure of a-Si:H preclude characterization by most conventional surface analytical techniques. Yet detailed information on the bonding and structure of surfaces, interfaces, and very thin films is crucial for multilayer photoelectronic device fabrication.
Oxidation Kinetics of Silicon Surfaces Studied Using Laser Induced Thermal Desorption
Authors: Gupta P. , Coon P.A. , Mak C.H. , George S.M.
Published: February 2023

The reaction of oxygen with silicon surfaces is of great fundamental and technological interest. In this paper, we report on laser-induced thermal desorption (LITD), temperature programmed desorption (TPD) and Fourier Transform Infrared (FTIR) experiments (1,2) that were used to investigate the kinetics of both the fast and slow steps in the oxygen adsorption process. These studies allowed the initial reactive sticking coefficient of oxygen on Si (111) 7x7 to be measured as a function of surface temperature. In addition, the kinetics of the slow adsorption step were studied on both Si (111)7x7 and porous silicon versus surface temperature.
Electron Beam Induced Film Deposition
Authors: Matsui Shinji , Ichihashi Toshinari , Mito Masanobu
Published: February 2023

A novel method for directly applying material on only a very small area of a substrate (selective deposition) at low temperature has been reported by applying a gas-substrate interface1-7). When an electron beam is irradiated onto a substrate in electron beam Chemical Vapor Deposition (CVD), source gas molecules, adsorbed on a substrate, are dissociated into nonvolatile and volatile materials. Nonvolatile materials are deposited on a substrate, which volatile materials are evacuated. Nanometer structures can be fabricated by electron beam CVD, using electron beam induced surface reaction, because beam diameters as small as 5 Å can be formed with conventional electron equipment8). Computer controlled direct writing also is possible for electron beam CVD. Metals, semiconductors, and inorganic materials can be deposited by this means. Thus, electron beam CVD has some excellent advantages over other CVD methods. Namely, processing methods in microelectronic devices can be simplified and new structure devices with nanometer dimensions can be realized. When source gas molecules adsorbed on a substrate are dissociated by electron beam irradiation, Auger electrons are emitted from deposited materials at the same time. Therefore, the deposited material growth process can be observed in situ by Auger electron spectroscopy (AES)3,7). Moreover, the deposited material growth process can be observed in situ by transmission electron microscopy (TEM), if source gas molecules are adsorbed on a TEM specimen5,6). This paper presents results obtained for AES and TEM W electron beam CVD observation in situ, using the WF6 source.
Electron-Transfer Mediated and Direct Surface Photochemistry: CH3Cl on Ni(111)
Authors: Marsh Eugene P. , Gilton Terry L. , Meier Wolfgang , Schneider Mark R. , Cowin J.P.
Published: February 2023

In the photochemistry of molecules on a metal or semiconductor, the surface can play a very important role by strongly perturbing, promoting or inhibiting the process.(1) Excitation to repulsive states is an important class of surface photochemical processes as they are: simple, bond specific, produce important reactive radicals, and are fast enough (5 to 100 fs) to largely escape electronic quenching due to surface interactions. However, charge transfer processes are still fast enough to perturb or dominate on this time scale.(2)
Activated-Dssociative Adsorption Studied Using Very Low Energy Ion Beams
Authors: Murata Yoshitada
Published: February 2023

The energy range from 1 to 100 eV will provide interesting chemical processes associated with a non-adiabatic process and the ion beam can be easily accelerated into the wide energy range. Moreover, the ion-surface interactions including surface reactions in this energy range are essential to elucidate the fundamental process in plasma deposition and others. However, very low energy (≤100 eV) ion beams have been scarcely employed in studying dynamical process on surfaces.
Laser-Induced Deposition of Amorphous Silicon: Relations between Chemical Processing and Performance
Authors: Hess Peter
Published: February 2023

Hydrogenated, amorphous silicon (a-Si:H) is of great interest for thin film devices used, for example, for the transformation of photon energy and as semiconductor material. Important applications are thin film solar cells, thin film transistors for liquid crystal displays, photoreceptors for electrophotography and laser printing and image sensors. To improve and optimize the properties of the material for specific applications it is necessary to control the formation of the three dimensional network during the solidification process ("bandgap engineering"). Incorporation of hydrogen into the network reduces the density of defects near the middle of the bandgap ("gap states"). For optimal performance a specific binding configuration should be realized. Distortions in the metastable silicon network, especially in the bond angle, are believed to be responsible for the tail states at the bandgap edges. Since these defect states constitute traps for charge carriers and thus lower their mobilities it is necessary to reduce the density of these states. To achieve an efficient control of the deposition process in this direction, detailed molecular information on the dynamic processes leading to solidification and on the structure-performance relationship is needed.
STM studies on the growth and structure of thin metallic films on metal substrates
Authors: Behm R.J.
Published: February 2023

The structure and growth of thin, epitaxially grown metal films vapor-deposited on metallic substrates have been studied by a variety of integrating techniques over many years [1]. On the theoretical side detailed predictions exist on both the structure and growth of these films, which were derived from considera-tions of the lattice mismatch between the respective materials and from their thermodynamical properties [2,3]. The verifica-tion of these predictions, however, requires an exact knowledge of the local structure and the topography of these films which was accessible only indirectly from these data. Scanning tunneling microscopy (STM) studies can provide direct information on these properties due to the local nature of the measurement which will be demonstrated in different examples.
Fast In-Situ Metallization: A Comparison of Several Methods with Possible Applications in High Density Multichip Interconnects
Authors: Widmer Marcel , Hoffmann Patrik , Lecohier Baudouin , Solka Herbert , Philippoz Jean-Michel , van den Bergh Hubert
Published: February 2023

Some recent results obtained using three quite different experimental approaches to fast in-situ surface metallization are presented. One of the goals is to make high density interconnects for multichip modules with metal contact width, height and pitch respectively of the order of 10, 5 and 25 μm. Direct writing speeds should be in excess of 1 cm/s. The first approach tried is to push classical pyrolytic laser chemical vapor deposition of copper from its bis-hexafluoroacetylacetonate Cu(hfa)2 to its limits. This is done by increasing the Cu(hfa)2 vapor pressure and by seeding the transparent surface of our substrate with a thin layer of a strongly light-absorbing substance. Speeds in the order of a few mm/s have already been obtained with good electrical properties and adhesion. The second approach tested implies metallization by thermal in-situ decomposition of a metal complex layer on a surface with a laser beam. The precursors used in this work are metal cluster coordination complexes, in particular au55(pɸ3)12c16 (ɸ stands for phenyl group -C6H5). Such molecules have a high metal content and advantageous thermal decomposition properties which enable writing speeds in excess of 1 cm/s while maintaining acceptable electrical properties of the metal lines. Finally, in a third approach, the fast in-situ step is limited to deposition of a thin metal line on the surface. These lines of only a few Å height are then "developed" in a second step to much high (of the order of one μm) and better conducting metal lines. This second step may be relatively slow, as many devices which have been patterned on their surface with the thin metal "prenucleation" lines can subsequently be developed simultaneously in a parallel processing step. An example of this approach is surface seeding using metals like Pt, W or Ir, followed by development by either selective low pressure CVD of copper from Cu(hfa)2, selective decomposition of a copper formate solid surface film, or selective electroless deposition from a copper bath. Possibilities of processing with much higher resolution using focussed charged particle beams are also briefly discussed.
Rotationally Anisotropic Second-Harmonic Generation Studies of the Structure and Thermal Stability of Cu(110)
Authors: Hoffbauer Mark A. , McVeigh Victoria J. , Zuerlein Michael J.
Published: February 2023

The microscopic structure and thermal stability of interfaces are of fundamental importance in determining a variety of materials properties. Order-disorder transitions on surfaces have recently received considerable attention in the scientific literature since the dynamics of such processes can impose fundamental limits on material performance at elevated temperatures. Many high-index (11n) faces (where n>2) of single-crystal metal surfaces are known to undergo this type of phasetransition. By definition, roughening of an atomically clean surface consists of the proliferation of atomic steps by thermal means at a roughening temperature, tr, where the surface free energy for creation of a step becomes zero. An unresolved question of fundamental importance is whether the roughening temperature of a low-index (110) surface can be lower than the bulk crystal melting temperature. For high index faces, a less stringent definition of roughening involving the proliferation of kinks on the already present step rows that can meander randomly has been suggested. The energy required for creation of a kink atom is lower than that required for generation of a step atom, thus roughening at temperatures lower than the bulk melting temperature can occur for stepped surfaces as opposed to low-index surfaces. Indeed, it has been shown shown both theoretically and experimentally that high-index faces of Cu, Ni, and other metals undergo roughening transitions well below the bulk melting temperatures.1
Vibrational Spectroscopy of Competive Adsorption at a Liquid/Solid Inteface Using IR-Visible Sum-Frequency Generation
Authors: Miragliotta J. , Polizzotti R.S. , Rabinowitz P. , Hall R.B.
Published: February 2023

Optical IR-Visible sum-frequency generation (SFG), a surface vibrational spectroscopy, has been used to study competitive adsorption at a hydroxylated ZrO2 surface in contact with a number of binary solutions. This technique is similar to surface second harmonic generation (SHG) in that it is forbidden (in the dipole approximation) in spatial regions possessing inversion symmetry. Therefore, systems consisting of an interface bound by centrosymmetric media give rise to a nonlinear response which is dominated by that of the interfacial region. In addition to being surface specific, the SFG signal from the liquid/solid interface can be resonantly enhanced when the incident IR laser source used in the generation process is tuned through a vibrational mode in the adsorbed species, provided the mode is both Raman and IR active. This vibrational information allows identification of the adsorbed molecule as well as measurements of surface coverage, molecular orientation, and adsorbate interactions for a number of the two-component liquid systems.
Arsenic Passivation of Silicon by Photo-assisted Metalorganic Vapour Phase Epitaxy
Authors: Rodway D C , Mackey K J , Smith P C , Vere A W
Published: February 2023

The MOVPE deposition of semiconductors requires effective substrate surface preparation, especially where low temperature, photo-assisted growth is involved. Ideally this process should be achieved in situ in the growth reactor immediately prior to deposition. In a previous paper(1) we reported the in situ removal of carbon from Si and GaAs substrate surfaces using 193nm radiation in a 1 Torr 02 ambient. This process generates a thin oxide which can then be removed by annealing at 850°C, although the process does not always go to completion. To protect the cleaned surface and to passivate the silicon substrate prior to deposition of GaAs we have explored the arsenic passivation techniques developed by Bringans et al(2,3) The oxidation resistance of surfaces prepared this way is also sufficient to permit transfer between laboratories for collaborative studies.
XPS Studies of Halogen Atom Beam Interactions with Electronic Materials
Authors: Freedman Andrew , Stinespring Charter D.
Published: February 2023

XPS studies of halogen atom beam (fluorine and chlorine) interactions with diamond (100) and GaAs (100) surfaces will be presented.
A Silicon Solid-State LED: Long-Lived Visible Electroluminescence from Silicon Nanocrystallites
Authors: Burr T. A. , Kolenbrander K. D.
Published: February 2023

We have constructed and characterized visible electroluminescent devices based on Si nanocrystallite thin films. The key to stable electroluminescent emission is the nature of the Si surface capping layer, which determines the efficiency and stability of the devices. The layers must be transparent to the emitted light, provide sufficient electrical contact to insure carrier transport to the active layer, stabilize the Si surfaces to prevent chemical and electrical degradation, and passivate the dangling surface bonds which would act as non-radiative recombination centers and quench emission. Our devices use Al and ITO (indium tin oxide) electrodes, as well as transparent polymer capping layers to provide the necessary carrier injection and chemical and electronic passivation for the silicon nanocrystallite active layer. Their electrical and optical behavior was evaluated in terms of the I-V characteristics, electroluminescence spectra, and photoluminescence spectra. These devices represent a first step towards developing efficient silicon based light-emitting technology.
STM Imaging of Electron Scattering and Confinement at Metal Surfaces
Authors: Avouris Phaedon
Published: February 2023

Electrons in Shockley-type metal surface states act as a quasi-two-dimensional free-electron gas (2DFEG). We show that scanning tunneling microscopy (STM) and spectroscopy (STS) can be used to study the interactions of this 2DFEG with features such as individual steps and adsorbed or embedded atoms1,2. Two approaches were utilized in our studies. One is based on the fact that an incident surface electron-wave when partially reflected by localized potentials such as those produced by steps, can interfere with the incident wave. This interference leads to an oscillatory local density-of-states near the step. Such oscillations were observed in dI/dV maps of Au(111) and Ag(111) surfaces. From dI/dV images as a function of the bias voltage the dispersion of the surface states and the scattering phase-shifts were obtained. Point-defects lead to isotropic scattering which appears in the form of concentric circles surrounding the defect. Because of the finite penetration depth of the surface state, not only adsorbed but also ebbeded species were found to act as scatterers. The electron oscillations observed at 300K decay exponentially as a function of the distance from the scattercr. We attribute this to the temperature-dependent Δk-width of the STS measurement which leads to the dephasing of the thus formed wave-packet. Another approach we used to study the interactions of the 2DFEG involves the spectroscopy of the onset region of the surface state band as a function of the distance from the scatterer2. In this way, the range of strong perturbation of the surface state was estimated to be 15-20 Å, and evidence was found for defect-induced bulk-surface state mixing.
Atomic Layer Controlled Deposition Of Al2O3 Films Employing Trimethylaluminum (TMA) And H2O Vapor
Authors: Ott A. W. , Dillon A.C. , Eaton H.K. , George S.M. , Way J.D.
Published: February 2023

The development of atomic layer controlled deposition processes has been a focus of recent research(1). The controlled growth of Al2O3 thin films has several important technological applications. For example, Al2O3 deposition on silicon surfaces is useful for the low temperature formation of high dielectric insulators.
Spectroscopy of an Electron in Zeolites: Time Domain Theory and the Modeling of the Material’s Properties
Authors: Metiu H. , Blake N.
Published: February 2023

We have developed a realistic model for the interaction of an electron or an ion with a zeolite frame and used a newly developed time dependent theory to calculate the spectroscopic properties of an electron absorbed in various zeolites.
Imaging Nanostructures with Near-Field Microscopy
Authors: Tsai Din Ping , Kovacs James , Othonos Andreas , Douketis Constantine , Zhang Peng , Moskovitis Martin
Published: February 2023

Near-field microscopy used in the apertured "photon scanning tunneling" mode was used to image a range on nanostructured systems including heterogeneous polymers, fiber Bragg gratings and colloid particle fractal assemblies.
Improving Combustion with Laser Diagnostics
Authors: Andresen Peter
Published: February 2023

Modern laser spectroscopic methods allow the simultaneous measurement of multiple species concentrations as well as temperature, pressure, and flow velocities. Such methods are applied to technically applied combustion systems like furnaces, internal combustion engines, jet engines, or wind tunnels.
Line-Shape Measurements by Tunable Diode Laser
Authors: Nadezhdinskii A.I.
Published: February 2023

Precision limitations of Tunable Diode Laser Spectroscopy (TDLS) are analyzed in relation to precise line-shape measurements such as baseline, optical zero, nonlinearity, laser noise, etc.) to affect experimental accuracy. Analytical expressions were derived for different error sources. An experimental procedure and data processing algorithm is proposed to minimize the error of line-shape parameters determination. It was shown that relative intensity measurements can be accurate within 0.3%.
A Paradigm for Object Recognition
Authors: Kim B. F. , Bohandy J. , Sigillito V. G.
Published: February 2023

A recognition paradigm is described here which has several characteristics thought to be important in the development of a general machine vision system. A general machine vision system is one which has capabilities similar to human vision. One of the principal features of the paradigm described here is that it learns to recognize objects by seeing them instead of requiring explicit models or rules which have been programmed into the computer. A vision system based upon this principle would be able to interpret visual scenes which fall within its realm of previous experience. Such is also the case in human vision. One can argue, in fact, that development of a general machine vision system will require that the visual memory be learned from its environment rather than programmed by a human. This point has recently been discussed by Haralick and Ulmann.1
Laser-Scanning Inspection Microscope System
Authors: Merkle F. , Bille J. , Hunklinger S. , Karte T. , Wijnaendts R.W. , Kaplan R.
Published: February 2023

A laser scanning system is described, resulting in processing speeds of up to 40 million pixels per second and spatial resolution down to 0.1 μm.
Phase Gratings for Range Sensing Based on Diffraction
Authors: Jenkins B.K.
Published: February 2023

A novel technique for range sensing has been described and demonstrated by Chavel and Strand [1] and Leger and Snyder [2]. While many other range sensing systems have been reported [3], this technique has the nearly unique advantage of detecting range over an entire image in real time (TV frame rates). This makes it particularly advantageous for use in many machine vision applications, e.g., industrial inspection and automated assembly.
Image-Plane Processing: Information, Fidelity, and Edge Detection
Authors: Huck Friedrich O. , Fales Carl L. , Stacy Kathryn
Published: February 2023

Suppose that an image-gathering system has been designed to maximize the information density of the acquired data without regard to the complexity of the image-forming process that may be needed to record all of this information. Suppose, furthermore, that the image-forming process restores an image from the acquired data with the utmost care to maximize image fidelity. Then, no other image-gathering system design (i.e., relationship between sampling passband, spatial response, and SNR) than the one that maximizes the acquired information density can be expected to further improve upon the fidelity of the restored image.
Combined Optimization of Image Gathering Optics and Image Processing Algorithm for Edge Detection
Authors: Halyo Nesim , Samms Richard W.
Published: February 2023

Much attention on edge detection has centered around the development of algorithms which process the sampled image data obtained by an image acquisition system [1]. While considerable work on designing (general-purpose) image gathering optics also exists the interrelationships between the two design processes has received little attention. This paper formulates a combined stochastic optimization problem where the optical transfer function (OTF) of the image gathering optics, the sampling lattice, the noise level and the image processing algorithm are all design parameters to be selected according to the optimization criterion. The optimization criterion used is the minimization of the spatially averaged mean-squared error in estimating a characteristic or a spatial feature related the object scene. Edge detection is treated as a special case of the general problem where the related characteristic contains edge information. This formulation recognizes that the objective is to determine the edges in the object scene rather than the edges of an already blurred and noisy image. As both image acquisition parameters and image processing algorithms can have significant effects on the mean-squared error, the optimization formulated provides an approach to obtain the most compatible acquisition and processing systems.
Architecture for Optical Generation of Invariant Contour Features
Authors: Giles C. Lee , Fisher Arthur D.
Published: February 2023

Pattern recognition features derived from a pattern's contour can be made invariant1,2 to the pattern's scale, position and rotation. Such features, (for example Fourier Descriptors), usually well characterize a pattern with a reduced feature set (in comparison to the feature set generated directly from two-dimensional gray-level patterns) and avoid, through smart segmentation, the problems of pattern shading. Contour features are significantly more sensitive to small changes in the pattern shape than the two-dimensional gray-level features. However, contour feature calculation is easily disrupted by contour discontinuities. Though contour features have been recently described in a hybrid optical-digital image processing system3, we describe an architecture which optically generates in parallel different classes of invariant contour features and is insensitive to small contour discontinuities. The normalization which generates invariant properties of these features is discussed.
On The Foundations of Tri-Nocular Machine Vision
Authors: Alloimonos John , Bandopadhay Amit , Chou Paul
Published: February 2023

A machine with three cameras can recover the depth map of the world in view, without having to solve the correspondence problem. Instead a macro-correspondence problem (identification of the same regions in the different images) is solved.
Automatic Shape Parametrisation in Machine Vision
Authors: Leavers V.F. , Boyce J.F.
Published: February 2023

A fully automatic, computational method is proposed which will allow the extraction of parameters characterising various shape primitives in the image space from their shape indicative distributions in a two dimensional parametric transform space.
Moire Contouring Using CCD Cameras
Authors: Koliopoulos Chris
Published: February 2023

Projection Moire Contouring of difuse objects is shown using the discreet sampling mature of CCD detector arrays as a Moire grading. Phase detection techniques allow the determination of the surface height of an object at each detector location to small fractions of the projected grading period. The surface height information over this uniform grid is independant of illumination variations on the object, and thus accurate contour measurements can be made.
Surface Representation and Shape Description of Solid Bodies
Authors: Eichmann G. , Jankowski M.
Published: February 2023

Modern image data collection techniques such as computed tomography, scanning electron microscopy, and digital stereoscopy make possible the computation of three-dimensional (3D) structure of scenes or objects. Such images are encountered in medical imaging, modeling of physical phenomena, geometric modeling and computer vision. There is a growing need in all these fields for efficient representation schemes of the 3D digital image. Of special interest in image description and modeling are surface methods, of which there are two general types. One is an interpolative method which expresses the surface by subdivisions known as surface primitives or patches (1,2). It is used in computer aided geometric design and computer graphics. The other is concerned with describing surfaces "in the large", mainly in terms of shape descriptors or globaly defined functions of the boundary(3). In either case parametric techniques are preferred since the representations are of lower dimensionality, are axes independent, and unambiguous for multivalued surfaces. Unfortunately 3D spatial data is most often encountered as objects in cellular space and the problem of parametrizing an arbitrary surface cannot in general be solved(4).
An Implementation of an Active Stereo Range Finder1
Authors: Medioni Gérard , Jezouin Jean-Luc
Published: February 2023

There is a strong need to have in a Computer Vision research laboratory a tool that performs quickly and efficiently the acquisition of range data. Furthermore this tool must be integrated in the environment of the laboratory, and should be able to bring a piece of solution to several current research problems, either by providing data for experiments, or by giving a ground-truth for some algorithms.
Machine Vision Measurement for Process Management In Automotive Assembly
Authors: Dewar Robert
Published: February 2023

The effectiveness of statistical analysis techniques in the management of manufacturing processes is well established, but application of these techniques in the automotive stamping and assembly environment has been difficult because the size and dimensional complexity of the product have made measurement of timely and statistically significant samples prohibitively expensive. Non-contact machine vision utilizing "structured light" or "optical sectioning" techniques overcomes this difficulty, permitting one, two, and three dimensional measurements to be automatically recorded and analysed at production line rates.
Manually Scanned Character Recognition System
Authors: Kidd Geoff , Tirkel Andy
Published: February 2023

This paper presents the design criteria and analysis of a novel, low cost, high speed, hand scanned instrument for recognition of printed text.
3-Dimensional Laser Radar Range Imaging
Authors: Jacobus C. , Tomko L. , Riggs A. , Sampson R.
Published: February 2023

This paper describes work done to design a three dimensional laser radar imaging system accurate to .004" and techniques for 3-D scene analysis used at the Environmental Research Institute of Michigan (ERIM).
Outdoor Model-Based Vision
Authors: Pentland A. , Bolles B. , Barnard S. , Fischler M.
Published: February 2023

DARPA’s Autonomous Land Vehicle (ALV) project is intended to develop and demonstrate vision systems capable of navigating in outdoor, natural environments. The major problems faced by this project, as we see it, are (1) developing a general-purpose vocabulary of models that are sufficient to describe most of the important landmarks that the vehicle will encounder, and (2) developing recognition techiques that will allow us to recognize these models from sensor data in both in a directed, top-down manner as well as in an unguided bottom-up fashion.
Compensated Imaging with Lightweight Telescopes using Real-Time Holography
Authors: Gruneisen Mark T. , Wilkes James M. , Clayton Christopher M.
Published: February 2023

Compensated imaging by real-time holography allows telescopes to be scaled to large apertures using light-weight, low-optical-quality primary mirrors. This application leads to unique requirements for real-time holographic media. Materials and devices under development for this application include nonlinear optical media and optically and electrically addressed spatial light modulators.
Cooled and Uncooled One-Channel Deformable Mirrors for Industrial Laser Machines
Authors: Safronov Andrey G.
Published: February 2023

Cooled and uncooled one-channel deformable mirrors for use in industrial laser machines for various applications have been developed and investigated. The design, technical parameters and effectiveness of the mirrors are described in detail. The experience of exploitation of the uncooled deformable mirrors is considered for two industrial laser machines based on: a) 2-kW cw-power CO-laser; b) 250-kW pulsed copper vapour laser.
Use of an LCPM to Simulate Time Varying Atmospheric Distortion for an Adaptive Optics System: Laboratory Demonstration
Authors: Gonglewski J. , Browne S. , Highland R. , Dayton D. , Sandven S.
Published: February 2023

Fast generation of known stimuli simulating atmospheric turbulence has long been an impossible dream for proving and characterizing adaptive optics systems. Now that liquid crystal phase modulators are available with a moderate number (>100) of elements, they can be readily employed to provide accurate and repeatable disturbances for the testing of adaptive optics. Moreover, their small size and low power dissipation make them ideal as on-board test sources with deterministic time-varying higher order phase screens.
Measurement of the Fast Oscillatory Potential and Light Rise of the Standing Potential Using the EOG
Authors: Pokorny Joel , Smith Vivianne C. , Gutterman Carl
Published: February 2023

We developed computer-controlled equipment to measure the fast oscillatory potential and light rise of the standing potential (Steinberg, Linsenmeier & Griff, Vision Res. 23:1315, 1983) using an electrooculographic (EOG) technique.
Visual Field Area Response to Increased Target Intensity as a Method of Detecting Ocular Disease
Authors: Williams T. David
Published: February 2023

Under normal conditions, the kinetic visual field increases in size when the intensity of the test target is increased.
The Screening for Visual Deficts Without the Use of Technical Equipment
Authors: Coren Stanley , Hakstian A. Ralph
Published: February 2023

Basic researchers have been pursuing genetical and environmental factors that may contribute to sensory deficts for a number of years. Their search has been supported by a steadily accruing body of data which indicates that there are systematic differences in sensory capacities among various subgroups of the population, defined in terms of their race, environmental or occupational history, as well as their nutritional condition, age and medical status. Much of this evidence comes from clinical sources, which indicate the prevalence of various ophthalmological problems which eventually reach a level of severity which requires medical intervention. From the researcher's point of view such data are valuable, however, they are quite limited in that they only consider the more extreme end of the continuum of sensory deficits. When one searches the literature to obtain normative data as to the prevalence of sensory deficits in nonclinical populations, little data are available. There are few large scale surveys of sensory abilities, and even epidemiological studies have little of this data.
A Rapid, Simple Means of Testing Kinetic Visual Fields in Young Children
Authors: Fausset Thomas , Enoch Jay M.
Published: February 2023

Because of the difficulty in handling young children, and in maintaining their fixation, routine perimetry is rarely performed in the clinic. With no modification, the commercially available Canon Fundus Photo-Perimeter allows ready measurements of visual fields in young children. To date, we have tested children from four to eight years of age. We are able to measure three isopters in a fifteen minute period, even in four year old children, using this device coupled with an ordinary VCR unit. We believe the method could be extended to include cooperative three year olds, with little difficulty.
Absolute Measurement of the Three-Dimensional Fundus Geometry with the Optic Nerve Head Analyzer.
Authors: Klingbeil U. , Wilms H. , Marx U.
Published: February 2023

The appearance of the human fundus is generally characterized in a qualitative way. Numbers such as the cup-to-disk ratio are based on estimations and thus subject to considerable interobserver variations. The Optic Nerve Head Analyzer is an instrument which has the capability of quantifying data for the colour and the structure of the retina specially the optic disk (1).
Displacement Threshold Hyperacuity and its resistance to optical image degradation
Authors: Whitaker David , Buckingham Terry
Published: February 2023

Assessing the location of visual disturbance in a patient suffering from vision loss is crucial in determining patient management. This task is often made difficult by the presence of media opacities which may reduce visual quality in combination with any retinal or neural dysfunction. A number of tests, of differing complexity, may be employed to differentiate between these two causes of vision loss. A recent addition to this test battery is the measurement of vernier acuity thresholds. These belong to the class of "hyperacuities" in that they are of a magnitude far smaller than conventional resolution acuities and appear to be unlimited by retinal receptor spacing or receptive field size. Their value lies in the fact that they demonstrate resistance to optical image degradation such as that produced by cataract, yet they are affected by any retinal or neural dysfunction.
Regression towards the Mean in Screening Strategies and Visual Disability Rating Scales
Authors: Smith Thomas J.
Published: February 2023

The term "regression" was first used in the 1889 by Sir Francis Gal ton in his book, Natural Inheritance (1). His Law of Universal Regression stated that "each peculiarity in man is shared by his kinsman, but on the average on a lesser degree". Under this law, for example, the sons of tall men, although tall, will be on average shorter than their fathers and the sons of short men although short, will tend to be taller than their fathers.
Multipole Sensitivity for Assessment of Abnormal Vision
Authors: Klein Stanley A. , Paul Adele D.
Published: February 2023

A battery of five spatially localized stimuli are proposed for measuring the complete range of visual sensitivity to spatial contrast. These stimuli are a ramp, an edge, a line, a dipole (a pair of adjacent opposite polarity lines), and a quadrupole (a pair of adjacent opposite polarity dipoles). The luminance profiles of the multipoles and the relationship of multipole sensitivity to grating sensitivity are shown in Figure 1 (mathematical details are at the end of this article).
Visual Function Evaluation of Patients with Retinopathy of Prematurity
Authors: Mayer D. Luisa , Trese Michael T.
Published: February 2023

A large-scale, cooperative effort to evaluate cryotherapy for retinopathy of prematurity (ROP) (stage III) is in progress and initial positive results of this trial have been reported (1). One component in the evaluation of outcome is grating acuity measured by the Teller Acuity Card (TAC) procedure (2). However, infants with more advanced ROP (stages IV-V) often do not have measurable TAC acuity (3, 4), yet, in clinical experience, react to light and may be capable of visually guided behavior. New studies are anticipated that will evaluate surgical intervention that may minimize disease progression in eyes with advanced ROP (eg. 5-7). These studies will need to employ measures of visual outcome that are appropriate for the functional level of vision of treated eyes.
Rod Visual Fields in Cone-Rod Degeneration: Comparisons To Retinitis Pigmentosa
Authors: Birch David G. , Anderson Jane L.
Published: February 2023

Cone-rod degeneration is characterized by atrophic macular degeneration with progressive decline in visual acuity and peripheral pigmentary disturbances with associated field loss1. The mode of inheritance is typically autosomal recessive2. Besides fundus appearance, patients with cone-rod degeneration can be distinguished from patients with retinitis pigmentosa on the basis of full-field electroretinography (ERG). Patients with cone-rod degeneration show markedly reduced cone ERG amplitudes with relative preservation of rod ERG amplitude. Rod b-wave implicit times are typically shorter than in patients with retinitis pigmentosa1,3-5. Rod sensitivity, as indexed by the semi-saturation constant (log k) of the Naka-Rushton function, is often only slightly elevated above normal4-5. These differences in rod ERG function suggest that the pattern of rod loss across the retina may differ between patients with cone-rod degeneration and patients with retinitis pigmentosa.
Temporal Response Properties of Optic Neuritis Patients Manifesting Statokinetic Dissociation (SKD)
Authors: Casson E. J. , Hwang Peter , Johnson Chris A. , Osako Masahiro
Published: February 2023

Statokinetic dissociation (SKD) refers to a greater impairment for detecting stationary targets (e.g., static perimetry) relative to detecting moving targets (e.g., kinetic perimetry). Riddoch (1917) originally described this phenomenon in a small group of patients with post-chiasmal lesions, although Zappia, Enoch, Stamper and Winkelman (1971) subsequently reported its presence in several cases of chiasmal disorders and optic neuropathies. Recent investigations (Safran and Glaser, 1980; Johnson and Keltner, 1980; Wedemeyer, Johnson and Keltner, 1989) indicate that SKD is probably most prevalent in optic nerve disease, particularly optic neuritis.
The a-wave of the ERG as a quantitative measure of human receptor activity
Authors: Hood Donald C. , Birch David G.
Published: February 2023

For over fifty years, the leading edge of the a-wave has been associated with receptor activity1. Uncertainty remains, however, about the answers to two basic questions: First, to what extent does the a-wave reflect receptor activity? For example, can we assume that the amplitude of the a-wave is linearly related to the size of the receptor's response? And, second, can we associate specific defects in receptor function with alterations in the leading edge of the a-wave? We are addressing these questions by comparing the leading edge of the rod a-wave to models of the rod receptor2,3.
Foveal Flicker Sensitivity In Eyes at Risk for Age-Related Maculopathy
Authors: Mayer Melanie J. , Spiegler Shari J. , Kim Charlene B. Y. , Ward Brian , Glues Andrew
Published: February 2023

Several labs are investigating noninvasive measures of retinal function which predict onset of exudative age-related maculopathy (ARM).1,2,3,4 The goal is to identify those at risk so that laser photocoagulation is not delayed when symptoms first appear. Three psychophysical performances have been associated with development of ARM-- loss of absolute (dark adapted) foveal sensitivity to long wavelength light,1,2 loss of S-cone sensitivity,2 and change in color discrimination.4 We report here that flicker sensitivity to long-wavelength, low spatial frequency light is also affected in eyes at risk for ARM.
Equilibrium Hue Loci in Diabetics: Evidence for Anomalies Beyond the Site of Chromatic Opponency
Authors: Schefrin Brooke E. , Werner John S. , Adams Anthony J.
Published: February 2023

Previous studies have shown that diabetics make tritan-like errors in color-matching experiments1,2 and demonstrate elevated increment thresholds for test lights detected by an S-cone mechanism3,4. While these experiments indicate the presence of a defect in visual pathways that receive an input from S-cones, they are unable to identify which components within these pathways are responsible for abnormal visual functions associated with diabetes. The purpose of this study is determine if diabetes introduces an anomaly either prior to and/or at the sites of cone interaction, or after the pooling of cone signals within chromatically-opponent pathways.