Marc Winterbottom

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.

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.

Effect of display resolution and antialiasing on the discrimination of simulated-aircraft orientation

Abstract In Experiment 1, antialiasing was found to improve performance on an orientation-discrimination task, whereas increasing display pixel-count did not. The latter finding was attributed to a decrease in image contrast associated with driving the CRT beyond its effective bandwidth. In Experiment 2, it was found that display resolution is the primary determinant of orientation-discrimination performance. This performance was not significantly improved by increasing antialiasing beyond a minimal level, suggesting that greater image detail can be substituted for antialias filtering. Finally, data obtained from an objective target-size calibration showed that nominal target size often does not accurately reflect the size (and hence distance) of simulated targets.

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.

System Dynamics Modeling of the Time Course of the Recognition-Primed Decision Model

Two types of decision-making processes have been identified in the literature: an analytical process and an intuitive process. One conceptual model of the latter is the recognition-primed decision (RPD) model (e.g., Klein, 2008). According to this model, decision making in naturalistic contexts entails a situational pattern-recognition process that, if subsequent expectancies are confirmed, leads the decision maker to render a decision to engage in a given course of action. In this paper, we describe a system dynamics model of Kleins RPD framework that focuses upon the dynamics of the decision-making process. The structure of our RPD model is based on a model of a set of laboratory phenomena called conjunction benefits and costs (e.g., L. R. Fournier, Patterson, Dyre, Wiediger, & Winters, 2007), which was extended to encompass the RPD framework. The results of our simulations suggest that decision priming (a bias toward rendering a given decision based on prior information) is a phenomenon that should occur in many naturalistic settings.

P‐76: Perceptual Tests of the Temporal Properties of a Shuttered LCD Projector

Abstract : Perceptual motion blur was studied in imagery presented on an LCD projector equipped with a mechanical shutter to reduce pixel hold-time. Perceptual measures of image blur were obtained with both a simple test stimulus, as well as real-world imagery. Both were found to correlate well with the measured pixel hold-time.

59.5L: Late‐News Paper: Evaluation of a Prototype Grating‐Light‐Valve Laser Projector for Flight Simulation Applications

An evaluation of a prototype grating light valve laser projector indicates it has properties well-suited to flight-simulation applications. Full-field luminance and contrast, spatial resolution, temporal resolution, and color stability were equal to or better than those of CRT projectors typically used in flight-simulator applications. In addition, this projector is capable of providing refresh rates greater than 60 Hz. The higher refresh rates eliminate perceived flicker, and greatly reduce (120 Hz) or eliminate (240 Hz) motion artifacts over the range of target speeds tested.

The influence of depth of focus on visibility of monocular head-mounted display symbology in simulation and training applications

The Joint Helmet Mounted Cueing System (JHMCS),is being considered for integration into the F-15, F-16, and F-18 aircraft. If this integration occurs, similar monocular head-mounted displays (HMDs) will need to be integrated with existing out-the-window simulator systems for training purposes. One such system is the Mobile Modular Display for Advanced Research and Training (M2DART), which is constructed with flat-panel rear-projection screens around a nominal eye-point. Because the panels are flat, the distance from the eye point to the display screen varies depending upon the location on the screen to which the observer is directing fixation. Variation in focal distance may create visibility problems for either the HMD symbology or the out-the-window imagery presented on the simulator rear-projection display screen because observers may not be able to focus both sets of images simultaneously. The extent to which blurring occurs will depend upon the difference between the focal planes of the simulator display and HMD as well as the depth of focus of the observer. In our psychophysical study, we investigated whether significant blurring occurs as a result of such differences in focal distances and established an optimal focal distance for an HMD which would minimize blurring for a range of focal distances representative of the M2DART. Our data suggest that blurring of symbology due to differing focal planes is not a significant issue within the range of distances tested and that the optimal focal distance for an HMD is the optical midpoint between the near and far rear-projection screen distances.