This article describes a new steerable endoscope for laparoscopic surgery. The steerable mechanism was inspired by the tentacles of squid and consists only of standard parts such as cables, coil springs, rings, and tubes. Laparoscopic surgery is carried out using an endoscope and long and slender instruments that are inserted through small incisions in the abdominal wall. The endoscope contains a light source and a camera that displays a picture of the abdominal cavity on a monitor in the operation room. The surgeon uses the instruments to carry out the operation while estimating the spatial position of the instruments and the organs from the camera picture. The mechanism can be easily miniaturized to a very small diameter, making it suitable for low-cost mass production of steerable endoscopes, instruments, and catheters. A patent for the mechanism has been applied for, and it is currently being commercialized.

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A new, easily miniaturized steerable endoscope

(1996) Situating Action II: Affordances for Interaction: The Social Is Material for Design Ecological Psychology: Vol 8, No 2, pp 111-129

Situating Action II: Affordances for Interaction: The Social Is Material for Design

BACKGROUND: Building on skills already learned in acquiring more complex or related skills is termed transfer of training (TOT). This study examined the TOT effects of previous open and laparoscopic surgical experience on a laparoscopic training module. STUDY DESIGN: Intracorporeal knot tying was chosen for evaluating TOT among three groups of surgical residents: interns (n = 11) with limited open and laparoscopic surgical experience, junior residents (n = 9) with recent and ongoing open and laparoscopic surgical experience, and senior residents (n = 8) with remote and limited laparoscopic experience but ongoing open surgical experience. After receiving a lecture, demonstration, and written instructions on three knot-tying techniques, residents rotated through three performance stations, one for each technique, over 2 days. After 15 minutes of practice, the residents were videotaped completing a test knot. Time to completion and economy of motion were recorded and analyzed. RESULTS: Junior residents had fewer performance errors than senior residents (reported as mean ± standard error of the mean) and were significantly faster than interns. No significant differences between interns and senior residents for mean time or error performance were observed. Senior residents did not demonstrate TOT from open surgical experience to laparoscopic knot tying. No significant differences were obtained across the three sessions for errors or for time. CONCLUSION: No evidence was found for TOT from open surgical experience to newly introduced laparoscopic knot-tying techniques or from one skill training session to a different skill session at least 4 hours later. This study indicates that specific minimally invasive surgery training is needed to develop laparoscopic surgery skills.

https://www.journalacs.org/article/S1072-7515(01)01069-9/pdf

Transfer of training in acquiring laparoscopic skills.

Left eye and right eye images of an autostereoscopic display are displayed on LCD spatial light modulators (1a,1b) which are illuminated by movable light sources (2a,2b) via converging lenses (3a,3b) or mirrors. A tracking system tracks the position of an observer and a control system controls the positions of the light sources (2a,2b) so that the images of the light sources formed by the lenses (3a,3b) or mirrors track the observer. The observer thus sees the 3D image while having an enlarged degree of freedom of movement.

Display for 3D images

A head guide with a display is attitudinally controlled for guiding the head of a passive viewer wherein the display is for viewing images that are emulative of images viewed by a cameraman with head mounted cameras whose head attitude is monitored for controlling the head guide in synchronism with the images gathered by the cameras. Additionally, the viewer's eyes may be induced to follow a sequence of visual fixations at the same time as the passive viewer's head is induced to execute attitudinal movements consistent therewith.

Apparatus for inducing attitudinal head movements for passive virtual reality

The hypothesis was tested that the coupling of parallax shifts between objects depicted on a monitor screen around a fixation point with the head movements of an observer viewing this screen monocularly around a point coinciding with the fixation point is sufficient to create a convincing depth impression and to enable the observer to make reliable estimations of depth. The estimates were based on monocular vision and involved the aligning of wedges. The investigation consisted of two analogous experiments carried out simultaneously, one on depth estimations virtually in the screen and one on depth estimations virtually in front of the screen. In each experiment three conditions were compared: an active condition in which the coupling of parallax shifts and observer's head movements operated, a passive condition in which it did not, and a real-life set-up to measure the maximum reliability in depth estimation. The hypothesis is confirmed: in the active condition the variances in the alignments are significantly smaller than in the passive condition and approach those in the real-life set-up. This holds not only for estimates in the screen but also for estimates in front of the screen, that is, we can make a thing apparently leap out of the screen towards the observer. Results are interpreted against the background of the debate between the direct and the indirect theories of perception.

Depth on a flat screen.

A method of causing an observer to get an three-dimensional impression of a scene from a two-dimensional representation thereof is disclosed. The observers movements, in particular the movements of his head and/or eyes are monitored and means are provided by which, depending on these movements, two-dimensional representations uniquely associated with each position of the head and/or eyes are displayed on a screen. According to the invention, the display means represent the relative parallactic displacements between all the objects in the scene relative to a predetermined fixation point in the scene.

A method of causing an observer to get a three-dimensional impression from a two-dimensional representation

W e reported the results of an experiment in which subjects experienced a convincing depth impression looking at a flat monitor screen (Smets, Overbeeke, & Stratmann, 1987). Parallax shifts around a fixation point between objects depicted on a monitor screen were coupled with the head movements of an observer who viewed this screen monocularly around a rotation point coinciding with the fixation point. This coupling proved to be necessary and sufficient to enable the observer to make reliable estimations of depth. The estimates involved the aligning of wedges \"in\" the screen and \"in front of\" the screen. The variance of estimates in the \"in\" the screen condition, where parallax shifts were coupled with head movements (active), differed significantly ( p < 0.01) from the variances of estimates in a fully analogous condition where this coupling did not exist (passive). The variance of estimates in the active condition even was small enough to allow practical applications. The variances in the \"in front of\" the screen conditions also differed significantly ( p < 0.01) but the variance of estimates in the active condition was too great to allow practical applications. W e predicted in the same article a decrease of this variance as the coupling between head and camera movements improves. To test this prediction we conducted an experiment using the same apparatus as the one described by Smets, et al. ( 1987), calibrating the camera between trials to optimize the coupling of camera and head movements. W e especially made sure the camera's fixation point and the observer's rotation point did coincide. W e asked 10 naive subjects (freshmen at the Department of Industrial Design), in exchange for a small reward, to make 10 estimates of depth \"in front of\" the screen aligning the wedge mounted before the screen with the wedge leaping apparently out of the screen. N o subject found this an odd task, which indicates the subjects really experienced a convincing depth effect. The mean and variance of estimates were again calculated over subjects and trials (M = -1.7 cm; SD = 1.8 cm). The variance was compared with the variance of estimates in the active \"in front of\" the screen condition of the previous experiment ( P Q ~ , ~ Q = 4.84, p < 0.01). There is a net decrease in the variance of estimates again indicating the importance of the coupling of camera and head movements.

Michael Heinrich Stratmann

Papers

Depth on a flat screen.

A method of causing an observer to get a three-dimensional impression from a two-dimensional representation

Depth on a flat screen: ii