Biomedical subjects

F A Voorhorst

Publications and source records attributed to F A Voorhorst.

3 recordsLinked to original sources

PubMed1999

Head-controlled laparoscopy: experiment, prototype, and preliminary results.

Depth perception is closely linked to the ability to explore. Previously described laboratory experiments showed the advantage of linking the motions of the laparoscope directly to the head movements of the surgeon. Additionally, it was found that the laparoscope should be mechanically supported instead of manually (by an assistant). This article describes three stages in the design and evaluation of a practical mechanism with which to link the motions of the laparoscope directly to the head movements of the surgeon. First, a description is given of the perceptual and technical considerations. Second, a laboratory experiment is described investigating the validity of the proposed suggestions. Last, a prototype was built that was tested in a practical setting.

Animals↗

PubMed1997

Spatial perception during laparoscopy: implementing action-perception coupling.

Laparoscopy is a telepresence task since the surgeon has no direct contract with the patient. Performance of the surgeon will increase if his sense of telepresence is improved. This can be achieved by restoring the hampered action perception coupling. With respect to visual perception this means that the surgeon should be informed about the spatial lay-out of the environment; depth information and information about the location of observation. Both types of information can be provided by allowing the surgeon to explore. This paper describes our work on restoring the action perception coupling with respect to visual perception. It provides an overview of different technical solutions which balance between what information should be provided from an perceptual stand point and what information can be provided from a technical viewpoint.

Depth Perception↗

PubMedDate not supplied

Using movement parallax for 3D laparoscopy.

The lack of depth perception hampers the surgeon during laparoscopic operation. Laparoscopes usually are monocular, but binocular ones are currently available. Depth perception, however, does not exclusively rely on binocular disparity. An observer, with only one eye, who is able to move that eye, obtains the same information as an observer who has two eyes. This principle of movement parallax can be applied to laparoscopy by coupling the head movements of the surgeon to the motions of the tip of the laparoscope. In an experiment we investigated if this principle is applicable to laparoscopy. Two groups of testees with no background in surgery were used. The first group was assisted by movement parallax, the second group was viewing a static image. Both groups of testees had to perform an exploration and a manipulation task. Since the amount of space for camera motion within the laparoscope is limited, implementation potential depends on the amount of movements that will be made by the observer. Therefore the movements of the observer performing the exploration task were registered and analysed. Results of the experiment indicate the advantage of movement parallax for the exploration task (performance increases by factor 2 while using only 30% more time) but not for the manipulation task. The analysis of the movements indicates that small movements are sufficient for implementation. Based on these results we concluded that movement parallax is applicable to laparoscopy.

Depth Perception↗