Biomedical subjects

Patricia R DeLucia

Publications and source records attributed to Patricia R DeLucia.

4 recordsLinked to original sources

PubMed2006

Visual memory for moving scenes.

In the present study, memory for picture boundaries was measured with scenes that simulated self-motion along the depth axis. The results indicated that boundary extension (a distortion in memory for picture boundaries) occurred with moving scenes in the same manner as that reported previously for static scenes. Furthermore, motion affected memory for the boundaries but this effect of motion was not consistent with representational momentum of the self (memory being further forward in a motion trajectory than actually shown). We also found that memory for the final position of the depicted self in a moving scene was influenced by properties of the optical expansion pattern. The results are consistent with a conceptual framework in which the mechanisms that underlie boundary extension and representational momentum (a) process different information and (b) both contribute to the integration of successive views of a scene while the scene is changing.

Color Perception↗

PubMed2006

Toward the improvement of image-guided interventions for minimally invasive surgery: three factors that affect performance.

OBJECTIVES: The objectives were to measure the impact of specific features of imaging devices on tasks relevant to minimally invasive surgery (MIS) and to investigate cognitive and perceptual factors in such tasks. BACKGROUND: Although image-guided interventions used in MIS provide benefits for patients, they pose drawbacks for surgeons, including degraded depth perception and reduced field of view (FOV). It is important to identify design factors that affect performance. METHOD: In two navigation experiments, observers fed a borescope through an object until it reached a target. Task completion time and object shape judgments were measured. In a motion perception experiment, observers reported the direction of a line that moved behind an aperture. A motion illusion associated with reduced FOV was measured. RESULTS: Navigation through an object was faster when a preview of the object's exterior was provided. Judgments about the object's shape were more accurate with a preview (compared with none) and with active viewing (compared with passive viewing). The motion illusion decreased with a rectangular or rotating octagonal viewing aperture (compared with circular). CONCLUSIONS: Navigation performance may be enhanced when surgeons develop a mental model of the surgical environment, when surgeons (rather than assistants) control the camera, and when the shape of the image is designed to reduce visual illusions. APPLICATION: Unintentional contact between surgical tools and healthy tissues may be reduced during MIS when (a) visual aids permit surgeons to maintain a mental model of the surgical environment, (b) images are bound by noncircular apertures, and (c) surgeons manually control the camera.

Humans↗

PubMed2005

Does binocular disparity or familiar size information override effects of relative size on judgements of time to contact?

Previous studies indicate that non-tau sources of depth information, such as pictorial depth cues, can influence judgements of time to contact (TTC). The effect of relative size on such judgements, the size-arrival effect, is particularly robust. However, earlier studies of the size-arrival effect did not include binocular disparity or familiar size information. The effects of these cues on relative TTC judgements were measured. Results suggested that disparity can eliminate the size-arrival effect but that the amount of disparity needed to do so is greater than typical stereoacuity thresholds. In contrast, familiar size eliminated the size-arrival effect even when disparity information was not available. Furthermore, disparity contributed more to performance when familiar size was present than when it was absent. Consistent with previous studies, TTC judgements were influenced by multiple sources of information. The present results suggested further that familiar size is one such source of information and that familiar size moderates the influence of binocular disparity information.

Female↗

PubMed2004

Time-to-contact judgments of an approaching object that is partially concealed by an occluder.

Prior studies of time-to-contact (TTC) focused on judgments of unoccluded approaching objects. P. R. DeLucia, M. K. Kaiser, J. M. Bush, L. E. Meyer, and B. T. Sweet (2003) showed that partial occlusion decreases an object's optical size and expansion rate and that the value of tau derived from the reduced optical size (relative rate of accretion; RRA) does not necessarily correspond to TTC. In the present study, a computer-generated object approached the observer while unoccluded or partially concealed by a stationary or moving occluder. In some scenes, the occluder's motion nullified the object's optical expansion. Results indicated that stationary and moving occluders affected TTC judgments. RRA predicted directional changes in TTC judgments but predicted larger changes in such judgments than were observed. Tau did not predict effects of occlusion. When developing models of perceived collision, it is important to consider effects of partial occlusion on optical TTC information and on TTC judgments.

Cues↗