Visualizing 3D Objects From 2D Cross Sectional Images DisplayedIn-Situ Versus Ex-Situ

摘要

The present research investigates how mental visualization of a 3D object from 2D cross sectional imagesis influenced by displacing the images from the source object, as is customary in medical imaging. Threeexperiments were conducted to assess people's ability to integrate spatial information over a series ofcross sectional images in order to visualize an object posed in 3D space. Participants used a hand-heldtool to reveal a virtual rod as a sequence of cross-sectional images, which were displayed either directlyin the space of exploration (in-situ) or displaced to a remote screen (ex-situ). They manipulated aresponse stylus to match the virtual rod's pitch (vertical slant), yaw (horizontal slant), or both. Consistentwith the hypothesis that spatial colocation of image and source object facilitates mental visualization, wefound that although single dimensions of slant were judged accurately with both displays, judging pitchand yaw simultaneously produced differences in systematic error between in-situ and ex-situ displays.Ex-situ imaging also exhibited errors such that the magnitude of the response was approximately correctbut the direction was reversed. Regression analysis indicated that the in-situ judgments were primarilybased on spatiotemporal visualization, while the ex-situ judgments relied on an ad hoc, screen-basedheuristic. These findings suggest that in-situ displays may be useful in clinical practice by reducing errorand facilitating the ability of radiologists to visualize 3D anatomy from cross sectional images.