1,682 research outputs found
Engineering data compendium. Human perception and performance. User's guide
The concept underlying the Engineering Data Compendium was the product of a research and development program (Integrated Perceptual Information for Designers project) aimed at facilitating the application of basic research findings in human performance to the design and military crew systems. The principal objective was to develop a workable strategy for: (1) identifying and distilling information of potential value to system design from the existing research literature, and (2) presenting this technical information in a way that would aid its accessibility, interpretability, and applicability by systems designers. The present four volumes of the Engineering Data Compendium represent the first implementation of this strategy. This is the first volume, the User's Guide, containing a description of the program and instructions for its use
Duchamp's Erotic Stereoscopic Exercises
This article explores certain links between medicine and art, with regard to their use of stereoscopy. I highlight a work by the artist Marcel Duchamp (the ready-made Stéréoscopie a la Main) and stereoscopic cards used in ophthalmic medicine. Both instances involve the drawing of graphic marks over previously existing stereoscopic cards. This similarity between Stéréoscopie a la Main and stereoscopic cards is echoed in the form of "stereoscopic exercises." Stereoscopic exercises were prescribed by doctors to be performed with the stereoscope as early as 1864. Stereoscopic cards were widely diffused in the 19th century, often promoted as "stay-at-home travel." It was over such kinds of materials that both Marcel Duchamp and doctors of ophthalmic medicine drew their graphic marks. I explore Duchamp's Stéréoscopie a la Main as a hypothetical basis for stereoscopic exercises of different types, proposing that this rectified ready-made is the locus for erotic stereoscopic exercises.Este artigo busca explorar certos elos entre a medicina e a arte por meio da estereoscopia. Destaca-se uma obra do artista Marcel Duchamp (o ready-made Stéréoscopie a la Main) e cartões estereoscópicos usados na oftalmologia. As duas instâncias envolvem o desenho de marcas gráficas sobre cartões estereoscópicos pré-existentes. A similaridade entre Stéréoscopie a la Main e os ditos cartões ecoa também na forma dos exercícios estereoscópicos. O cartão estereoscópico foi amplamente difundido na segunda metade do séc. XIX, frequentemente na forma da "viagem sem sair de casa." Foi sobre esse tipo de material que tanto médicos quanto Marcel Duchamp desenharam suas marcas. Explora-se a obra Stéréoscopie a la Main como um sítio hipotético para uma espécie de exercício, propondo que tal ready-made retificado seja um lugar para exercícios estereoscópicos eróticos
The Mid-Infrared Instrument for the James Webb Space Telescope, V: Predicted Performance of the MIRI Coronagraphs
The imaging channel on the Mid-Infrared Instrument (MIRI) is equipped with
four coronagraphs that provide high contrast imaging capabilities for studying
faint point sources and extended emission that would otherwise be overwhelmed
by a bright point-source in its vicinity. Such bright sources might include
stars that are orbited by exoplanets and circumstellar material, mass-loss
envelopes around post-main-sequence stars, the near-nuclear environments in
active galaxies, and the host galaxies of distant quasars. This paper describes
the coronagraphic observing modes of MIRI, as well as performance estimates
based on measurements of the MIRI flight model during cryo-vacuum testing. A
brief outline of coronagraphic operations is also provided. Finally, simulated
MIRI coronagraphic observations of a few astronomical targets are presented for
illustration
Deformable Beamsplitters: Enhancing Perception with Wide Field of View, Varifocal Augmented Reality Displays
An augmented reality head-mounted display with full environmental awareness could present data in new ways and provide a new type of experience, allowing seamless transitions between real life and virtual content. However, creating a light-weight, optical see-through display providing both focus support and wide field of view remains a challenge. This dissertation describes a new dynamic optical element, the deformable beamsplitter, and its applications for wide field of view, varifocal, augmented reality displays. Deformable beamsplitters combine a traditional deformable membrane mirror and a beamsplitter into a single element, allowing reflected light to be manipulated by the deforming membrane mirror, while transmitted light remains unchanged. This research enables both single element optical design and correct focus while maintaining a wide field of view, as demonstrated by the description and analysis of two prototype hardware display systems which incorporate deformable beamsplitters. As a user changes the depth of their gaze when looking through these displays, the focus of virtual content can quickly be altered to match the real world by simply modulating air pressure in a chamber behind the deformable beamsplitter; thus ameliorating vergence–accommodation conflict. Two user studies verify the display prototypes’ capabilities and show the potential of the display in enhancing human performance at quickly perceiving visual stimuli. This work shows that near-eye displays built with deformable beamsplitters allow for simple optical designs that enable wide field of view and comfortable viewing experiences with the potential to enhance user perception.Doctor of Philosoph
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Reproducing reality with a high-dynamic-range multi-focal stereo display
With well-established methods for producing photo-realistic results, the next big challenge of graphics and display technologies is to achieve perceptual realism --- producing imagery indistinguishable from real-world 3D scenes. To deliver all necessary visual cues for perceptual realism, we built a High-Dynamic-Range Multi-Focal Stereo Display that achieves high resolution, accurate color, a wide dynamic range, and most depth cues, including binocular presentation and a range of focal depth. The display and associated imaging system have been designed to capture and reproduce a small near-eye three-dimensional object and to allow for a direct comparison between virtual and real scenes. To assess our reproduction of realism and demonstrate the capability of the display and imaging system, we conducted an experiment in which the participants were asked to discriminate between a virtual object and its physical counterpart. Our results indicate that the participants can only detect the discrepancy with a probability of 0.44. With such a level of perceptual realism, our display apparatus can facilitate a range of visual experiments that require the highest fidelity of reproduction while allowing for the full control of the displayed stimuli.</jats:p
Factors affecting brightness and colour vision under water
Both theoretical and practical importance can be attached to attempts to model human threshold and supra-threshold visual performance under water. Previously, emphasis has been given to the integration of visual data from experiments conducted in air with data of the physical specification of the underwater light field. However, too
few underwater studies have been undertaken for the validity of this approach to be assessed. The present research therefore was concerned with the acquisition of such data.
Four experiments were carried out: (a) to compare the predicted and obtained detection thresholds of achromatic targets, (b) to measure the relative recognition thresholds
of coloured targets, (c) to compare the predicted and obtained supra-threshold appearance of coloured targets at various viewing distances and under different experimental instructions, (d) to compare the predicted and obtained detection thresholds for achromatic targets under realistic search conditions. Within each experiment, observers were tested on visual tasks in the field and in laboratory
simulations. Physical specifications of targets and backgrounds were determined by photometry and spectroradiometry.
The data confirmed that: (a) erroneous predictions of the detection threshold could occur when the contributions of absorption and scattering to the attenuation of light
were not differentiated, (b) the successful replication of previous findings for the relative recognition thresholds of colours depended on the brightness of the targets, (c) the perceived change in target colour with increasing viewing distance was less than that measured physically, implying the presence of a colour constancy mechanism other than chromatic adaptation and simultaneous colour contrast; the degree of colour constancy also varied with the type of target and experimental instructions, (d) the successful prediction of the effects of target-observer motion and target location
uncertainty required more than simple numerical corrections to the basic detection threshold model. It was concluded that further progress in underwater visibility modelling is possible provided that the tendency to oversimplify human visual performance is suppressed
Modern lithographic techniques applied to stereographic imaging
The main aim of the research has been to produce and evaluate a high-quality diffusion
screen to display projected film and television images. The screens have also been found
to effectively de-pixelate LCD arrays viewed at a magnification of approximately 4x.
The production process relies on the formation of localized refractive index gradients in a
photopolymer. The photopolymer, specially formulated and supplied by Du Pont, is
exposed to actinic light through a precision contact mask to initiate polymerization within
the exposed areas. As polymerization proceeds, a monomer concentration gradient exists
between the exposed and unexposed regions allowing the monomer molecules to diffuse.
Since the longer polymer chains do not diffuse as readily, the molecular concentration of
the material, which is related to its refractive index, is then no longer uniform. The
generation of this refractive index profile can, to some extent, be controlled by careful
exposure of the photopolymer through the correct mask so that the resulting diffusion
screen can be tailored to suit specific viewing requirements. [Continues.
Perceived Depth Control in Stereoscopic Cinematography
Despite the recent explosion of interest in the stereoscopic 3D (S3D) technology, the ultimate prevailing of the S3D medium is still significantly hindered by adverse effects regarding the S3D viewing discomfort. This thesis attempts to improve the S3D viewing experience by investigating perceived depth control methods in stereoscopic cinematography on desktop 3D displays. The main contributions of this work are: (1) A new method was developed to carry out human factors studies on identifying the practical limits of the 3D Comfort Zone on a given 3D display. Our results suggest that it is necessary for cinematographers to identify the specific limits of 3D Comfort Zone on the target 3D display as different 3D systems have different ranges for the 3D Comfort Zone. (2) A new dynamic depth mapping approach was proposed to improve the depth perception in stereoscopic cinematography. The results of a human-based experiment confirmed its advantages in controlling the perceived depth in viewing 3D motion pictures over the existing depth mapping methods. (3) The practicability of employing the Depth of Field (DoF) blur technique in S3D was also investigated. Our results indicate that applying the DoF blur simulation on stereoscopic content may not improve the S3D viewing experience without the real time information about what the viewer is looking at. Finally, a basic guideline for stereoscopic cinematography was introduced to summarise the new findings of this thesis alongside several well-known key factors in 3D cinematography. It is our assumption that this guideline will be of particular interest not only to 3D filmmaking but also to 3D gaming, sports broadcasting, and TV production
Panoramic, large-screen, 3-D flight display system design
The report documents and summarizes the results of the required evaluations specified in the SOW and the design specifications for the selected display system hardware. Also included are the proposed development plan and schedule as well as the estimated rough order of magnitude (ROM) cost to design, fabricate, and demonstrate a flyable prototype research flight display system. The thrust of the effort was development of a complete understanding of the user/system requirements for a panoramic, collimated, 3-D flyable avionic display system and the translation of the requirements into an acceptable system design for fabrication and demonstration of a prototype display in the early 1997 time frame. Eleven display system design concepts were presented to NASA LaRC during the program, one of which was down-selected to a preferred display system concept. A set of preliminary display requirements was formulated. The state of the art in image source technology, 3-D methods, collimation methods, and interaction methods for a panoramic, 3-D flight display system were reviewed in depth and evaluated. Display technology improvements and risk reductions associated with maturity of the technologies for the preferred display system design concept were identified
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