Two experiments examined the effects of pictorial realism, observer interactivity, and delay of visual feedback on the sense of "presence." Subjects were presented pairs of virtual enviornments (a simulated driving task) that differed in one or more ways from each other. After subjects had completed the second member of each pair they reported which of the two had produced the greater amount of presence and indicated the size of this difference by means of a 1-100 scale. As predicted, realism and interactivity increased presence while delay of visual feedback diminished it. According to subjects' verbal responses to a postexperiment interview, pictorial realism was the least influential of the three variables examined. Further, although some subjects reported an increase in the sense of presence over the course of the experiment, most said it reamined unchanged or became weaker. Disciplines Business | Cognition and Perception | Marketing | Neurology | Neurosciences | Ophthalmology | Optometry | PsychiatryAbstract Two experiments examined the effects of pictorial realism, observer interactivity, and delay of visual feedback on the sense of "presence." Subjects were presented pairs of virtual environments (a simulated driving task) that differed in one or more ways from each other. After subjects had completed the second member of each pair they reported which of the two had produced the greater amount of presence and indicated the size of this difference by means of a I -100 scale. As predicted, realism and interactivity increased presence while delay of visual feedback diminished it. According to subjects' verbal responses to a postexperiment Interview, pictorial realism was the least influential of the three variables examined. Further, although some subjects reported an increase In the sense of presence over the course of the experiment, most said that it had remained unchanged or become weaker. I produce, by means ofa computer program and accompanying hardware (e.g., a DataGlove), the same experiences of clarity, completeness, vivacity, continuity, constancy, and presence that occur in normal perception (e.g., Stark, 1994).

Abstract. The Mars Pathfinder mission used a unique capability to rapidly generate and interactively display three-dimensional (3-D) photorealistic virtual reality (VR) models of the Martian surface. An interactive terrain visualization system creates and renders digital terrain models produced from stereo images taken by the Imager for Mars Pathfinder (IMP) camera. The stereo pipeline, an automated machine vision algorithm, correlates features between the left and right images to determine their disparity and computes the corresponding positions using the known camera geometry. These positions are connected to form a polygonal mesh upon which IMP images are overlaid as textures. During the Pathfinder mission, VR models were produced and displayed almost as fast as images were received. The VR models were viewed using MarsMap, an interface that allows the model to be viewed from any perspective driven by a standard three-button computer mouse. MarsMap incorporates graphical representations of the lander and rover and the sequence and spatial locations at which rover data were taken. Graphical models of the rover were placed in the model to indicate the rover position at the end of each day of the mission. Images taken by Sojourner cameras are projected into the model as 2-D "billboards" to show their proper perspective. Distance and angle measurements can be made on features viewed in the model using a mouse-driven 3-D cursor and a point-andclick interface. MarsMap was used to assist with archiving and planning Sojourner activities and to make detailed measurements of surface features such as wind streaks and rock size and orientation that are difficult to perform using 2-D images. Superresolution image processing is a computational method for improving image resolution by a factor of n 1/2 by combining n independent images. This technique was used on Pathfinder to obtain better resolved images of Martian surface features. We show results from superresolving IMP camera images of six targets including near-and far-field objects and discuss how the resolution improvement aids interpretation. Similar flood deposits can be seen on both of the Twin Peaks that cannot be resolved in raw images. Millimeter-sized pits are resolved on the rocks Wedge and Halfdome. Other rocks at the Pathfinder site exhibit fine-scale layering that is otherwise invisible. Use of the method resulted in the probable discovery of an artifact of intelligent life on Mars: a part of the Pathfinder spacecraft. IntroductionPathfinder was the first rover mission to Mars, but it will not be the last. Rover missions are able to perform many of the functions of a field geologist [Stoker, 1996[Stoker, , 1998]. For example, a field geologist is able to look around, construct a mental three-dimensional (3-D) model of the nearby surroundings; perform measurements of nearby objects; determine slopes, strike, and dip of the distant terrain; and construct detailed maps of the region. The geologist also uses binoculars to get improved resolution of distant fe...

The repetitive scanpath eye movement, EM, sequence enabled an approach to the representation of visual images in the human brain. We supposed that there were several levels of binding-semantic or symbolic binding; structural binding for the spatial locations of the regions-of-interest; and sequential binding for the dynamic execution program that yields the sequence of EMs. The scanpath sequences enable experimental evaluation of these various bindings that appear to play independent roles and are likely located in different parts of the modular cortex. EMs play an essential role in top-down control of the flow of visual information. The scanpath theory proposes that an internal spatial-cognitive model controls perception and the active looking EMs. Evidence supporting the scanpath theory includes experiments with ambiguous figures, visual imagery, and dynamic scenes. It is further explicated in a top-down computer vision tracking scheme for telerobots using design elements from the scanpath procedures. We also introduce procedures-calibration of EMs, identification of regions-of-interest, and analysis and comparison programs-for studying scanpaths. Although philosophers have long speculated that we see in our mind's eye, yet until the scanpath theory, no strong scientific evidence was available to support these conjectures.

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