Byron J. Pierce

Perceptual Issues in the Use of Head-Mounted Visual Displays

Objective: We provide a review and analysis of much of the published literature on visual perception issues that impact the design and use of head-mounted displays (HMDs). Background: Unlike the previous literature on HMDs, this review draws heavily from the basic vision literature in order to help provide insight for future design solutions for HMDs. Method: Included in this review are articles and books found cited in other works as well as articles and books obtained from an Internet search. Results: Issues discussed include the effect of brightness and contrast on depth of field, dark focus, dark ergence, and perceptual constancy; the effect of accommodation-vergence synergy on perceptual constancy, eyestrain, and discomfort; the relationship of field of view to the functioning of different visual pathways and the types of visual motor tasks mediated by them; the relationship of binocular input to visual suppression; and the importance of head movements, head tracking, and display update lag. Conclusion: This paper offers a set of recommendations for the design and use of HMDs. Application: Consideration of the basic vision literature will provide insight for future design solutions for HMDs.

Compact HMD optics based on multiplexed aberration-compensated holographic optical elements

Head and helmet mounted displays (HMDs) can benefit greatly from new wide field-of-view, compact visor optics to project very high resolution (e.g., 5k X 4k) imagery. Physical Optics Corporation (POC) is developing novel, compact, lightweight wide field-of-view optics based on three-color multiplexed aberration-compensated holographic optical elements (MAC-HOEs). Taking advantage of the flexibility of holography, the HMD optics can be made compact using waveguide projection through the curved visor substrate, so that the see-through visor can have a wide field-of-view without large, bulky optical components. Using narrowband red-green-blue hologram multiplexing, MAC-HOEs can significantly reduce the chromatic and geometrical aberration introduced by conventional HOEs and refractive optics. In the initial phase of development, POC demonstrated the feasibility of the HMD optics through computer design and analysis, and by fabricating and demonstrating a MAC-HOE component.

Depth interactions between inclined and slanted surfaces in vertical and horizontal orientations

Depth interactions between a frontal test surface and an adjacent induction surface were measured as a function of the type of disparity in the induction surface and of the vertical/horizontal orientation of the boundary between the surfaces. The types of disparity were 4° horizontal-shear disparity, 4° vertical-shear disparity, and 4° rotation disparity; 4% horizontal-size disparity, 4% vertical-size disparity, and 4% overall-size disparity. Depth contrast in a frontal surface was produced by surfaces containing horizontal-size disparity but not by those containing horizontal-shear disparity. Vertical-shear and vertical-size disparities produced induced effects in both the induction and the test surface, which is here explained in terms of deformation-disparity processing. Effects of rotation disparity on the test surface can be accounted for in terms of cyclovergence, deformation disparity, and perhaps also depth contrast. The fact that horizontal-size disparity produced more depth contrast than horizontal-shear disparity is due to an anisotropy of disparity processing rather than the relative orientation of the surfaces. Ground surfaces appeared more slanted than ceiling surfaces. Surfaces containing horizontal disparities produced a sharp boundary with the test surface because horizontal disparities are processed locally. Surfaces with vertical disparities produced a gradual boundary with the test surface because vertical disparities are processed over a wider area.

Training Robust Decision Making in Immersive Environments

We provide a review and analysis of much of the published literature on decision making that is relevant to the design of immersive environments. This review draws from the basic and applied literature in order to provide insight for the design of such synthetic environments. Included in this review are articles and books cited in other works, and articles and books obtained from an Internet search. Issues discussed are (a) an overview of immersive decision environments; (b) dual-process decision making; (c) training robust intuitive decision making; (d) combining analytical and intuitive processing in immersive environments; and (e) concluding remarks. For the development of robust decision making in immersive environments, intuitive reasoning should be emphasized by creating an immersive situation and by providing for the development of automatic processing through implicit learning, with the latter reinforced by explicit thought processes. Considerations of the literature on decision making will provide insight for future design solutions for immersive decision environments.

Binocular rivalry and head-worn displays.

Objective: We provide a review and analysis of much of the published literature on binocular rivalry that is relevant to the design and use of head-worn displays (HWDs). Background: This review draws heavily from both the basic vision literature and applied HWD literature in order to help provide insight for minimizing the effects of binocular rivalry when HWDs are worn. Method: Included in this review are articles and books found cited in other works as well as articles and books obtained from an Internet search. Results: Issues discussed and summarized are (a) characteristics of binocular rivalry, (b) stimulus factors affecting rivalry, (c) cognitive variables affecting rivalry, and (d) tasks affected by rivalry. Conclusion: This paper offers a set of recommendations for minimizing the effects of binocular rivalry when HWDs are used as well as recommendations for future research. Application: Considerations of the basic vision literature on binocular rivalry will provide insight for future design solutions for HWDs.

Implicit Learning, Tacit Knowledge, Expertise Development, and Naturalistic Decision Making

Implicit learning involves the largely unconscious learning of dynamic statistical patterns and features, which leads to the development of tacit knowledge. This kind of learning is a ubiquitous, robust phenomenon that likely occurs in most, if not all, tasks in which individuals engage throughout their lives. In this paper, we argue that implicit learning and its end state, tacit knowledge, may assist in the acquisition, retention, and transfer of expertise and thus provide a form of tacit scaffolding for expertise development. The notion of tacit scaffolding represents a novel and interesting area of future research for the field of naturalistic decision making and naturalistic cognition.

Types of Size Disparity and the Perception of Surface Slant

We examined (i) perceived slant of a textured surface about a vertical axis as a function of disparity magnitude for horizontal-size disparity, vertical-size disparity, and overall-size disparity; and (ii) interactions between patterns with various types and magnitudes of size disparity and superimposed or adjacent zero-disparity stimuli. Horizontal-size disparity produced slant which increased with increasing disparity, was enhanced by superimposed zero-disparity stimuli, and induced contrasting slant in superimposed or adjacent zero-disparity stimuli. Vertical-size disparity produced opposite slant (induced effect) which was reduced to near zero by a superimposed zero-disparity pattern and both patterns appeared as one surface. Adjacent vertical-size-disparity and zero-disparity patterns appeared as separate surfaces with a wide curved boundary. Overall-size disparity produced slant which was enhanced by a superimposed zero-disparity pattern and less so by a zero-disparity line, and induced more slant in a zero-disparity line than in a zero-disparity pattern. The results are discussed in terms of depth underestimation of isolated surfaces, depth enhancement, depth contrast, and the processing of deformation disparity.

Training Intuitive Decision Making in a Simulated Real-World Environment

Objective: We investigated whether naturalistic, intuitive (pattern recognition–based) decision making can be developed via implicit statistical learning in a simulated real-world environment. Background: To our knowledge, no definitive studies have actually shown that implicit learning plays a causal role in the development of intuitive decision making when the latter is defined as pattern recognition of real-world, or simulated real-world, environmental situations. Method: The simulated environment was presented dynamically so as to induce a sense of simulated locomotion through the scene and over sequences of objects on the ground. During training, participants passively viewed the objects sequences; during test, participants made intuitive decisions about related or unrelated sequences. Results: Intuitive decision making can be developed via implicit learning. Articulatory suppression, which affects working memory, exerted a significant inhibitory effect on the training of intuitive decision making. Intuitive decision making trained in the simulated environment fully transferred to a flat display (but not vice versa). Conclusion: Intuitive decision making is developed by an implicit learning process that is engaged by the meaning inherent in naturalistic scenes. Application: Implicit learning can be used for training intuitive decision making.

P-39: Perceptual Tests of the Temporal Response of a Shuttered LCoS Projector

Perceptual motion blur was studied using imagery presented on an LCoS projector equipped with a mechanical shutter to reduce pixel hold-time. Perceptual measures of image blur were obtained with a simple test stimulus, as well as imagery similar to that used in Air Force flight simulation and training. Measured pixel hold-time was found to accurately predict perceived blur.

Visual suppression of monocularly presented symbology against a fused background in a simulation and training environment

When wearing a monocular head-mounted display (HMD), one eye views the HMD symbology while both eyes view an out-the-window scene. This may create interocular differences in image characteristics that could disrupt binocular vision by provoking visual suppression, thus reducing visibility of the background scene, monocular symbology, or both. However, binocular fusion of the background scene may mitigate against the occurrence of visual suppression, a hypothesis that was investigated in the present study. Observers simultaneously viewed a static background scene and HMD symbology while performing a target recognition task under several viewing conditions. In a simulated HMD condition observers binocularly viewed a background scene with monocular symbology superimposed. In another condition, viewing was dichoptic (i.e. completely different images were presented to the left and right eyes). Additionally, one control condition was implemented for comparison. The results indicate that for continuously presented targets binocular rivalry did not have significant effects on target visibility. However, for briefly presented targets, binocular rivalry was shown to increase thresholds for target recognition time in HMD and dichoptic viewing conditions relative to the control. Impairment was less in the HMD condition. Thus, binocular fusion of a background scene can partially mitigate against the occurrence of visual suppression. However, some suppression still exists which occurs between monocular pathways. Implications for the integration of monocular HMDs into Air Force training environments will be discussed.