Search PubMed⌕ Search

Biomedical subjects

George W McConkie

Publications and source records attributed to George W McConkie.

5 recordsLinked to original sources
PubMed2003

Gaze-contingent multiresolutional displays: an integrative review.

Gaze-contingent multiresolutional displays (GCMRDs) center high-resolution information on the user's gaze position, matching the user's area of interest (AOI). Image resolution and details outside the AOI are reduced, lowering the requirements for processing resources and transmission bandwidth in demanding display and imaging applications. This review provides a general framework within which GCMRD research can be integrated, evaluated, and guided. GCMRDs (or "moving windows") are analyzed in terms of (a) the nature of their images (i.e., "multiresolution," "variable resolution," "space variant," or "level of detail"), and (b) the movement of the AOI (i.e., "gaze contingent," "foveated," or "eye slaved"). We also synthesize the known human factors research on GCMRDs and point out important questions for future research and development. Actual or potential applications of this research include flight, medical, and driving simulators; virtual reality; remote piloting and teleoperation; infrared and indirect vision; image transmission and retrieval; telemedicine; video teleconferencing; and artificial vision systems.

Data Display↗
PubMed2003

Word identification and eye fixation locations in visual and visual-plus-auditory presentations of spoken sentences.

In this study, we investigated where people look on talkers' faces as they try to understand what is being said. Sixteen young adults with normal hearing and demonstrated average speechreading proficiency were evaluated under two modality presentation conditions: vision only versus vision plus low-intensity sound. They were scored for the number of words correctly identified from 80 unconnected sentences spoken by two talkers. The results showed two competing tendencies: an eye primacy effect that draws the gaze to the talkers eyes during silence and an information source attraction effect that draws the gaze to the talker's mouth during speech periods. Dynamic shifts occur between eyes and mouth prior to speech onset and following the offset of speech, and saccades tend to be suppressed during speech periods. The degree to which the gaze is drawn to the mouth during speech and the degree to which saccadic activity is suppressed depend on the difficulty of the speech identification task. Under the most difficult modality presentation condition, vison only, accuracy was related to average sentence difficulty and individual proficiency in visual speech perception, but not to the proportion of gaze time directed toward the talkers mouth or toward other parts of the talker's face.

Adolescent↗
PubMed2002

Perception onset time during fixations in free viewing.

In this study, we investigated when visual perception begins in fixations. During picture viewing, the picture was degraded at the beginning of selected saccades and changed back to the original after varying intervals. Participants manually responded whenever they detected changes. The change-backs were undetected when they occurred <6 msec after the end of the saccade, marked by the peak of the overshoot in dual Purkinje image eyetracker data, and detection reached asymptote 32 msec after that marker. Eye velocity at the change-back time also affected detection likelihood. Apparently, perception begins around the time at which the eyes stop rotating at the end of a saccade, giving a psychological justification for measuring fixation durations from then. This also specifies the deadline for gaze-contingent display changes to occur without detectable image motion. Investigators using the dual Purkinje image eyetracker should consider the peak of the overshoot as the fixation onset time and measure intrafixational presentation times from then.

Fixation, Ocular↗
PubMed2002

Investigating spatial vision and dynamic attentional selection using a gaze-contingent multiresolutional display.

This study examined spatial vision and attentional selection using a gaze-contingent multiresolutional display, with a dynamic, gaze-centered, high-resolution window and lower resolution periphery. Visual search times and eye movements from 15 participants in a 3 x 3 design (Window Radius x Peripheral Resolution) suggest that contrast sensitivity as a function of retinal eccentricity affects attentional selection and visual processing. Smaller windows led to longer search times and shorter saccades; lower peripheral resolution also shortened saccades (all ps < .05) as a result of avoiding fixating degraded areas. Fixation durations, although longer for smaller windows (p < .05), were unaffected by whether the next saccade went within or outside the window. These results are explained through (a) competition among potential saccade targets where above-threshold filtering reduces an object's relative salience and (b) generally disrupted visual processing.

Adult↗