Stereoscopic Visualization and 3-D Technologies in Medical Endoscopic Teleoperation

Stereoscopic 3-D visualization (S3D) provides a user with higher comprehension of remote environments in teleoperation when compared to 2-D viewing. Studies in the literature have shown how stereo vision may contribute to improving perception of some depth cues, but it is hard to find work assessing stereoscopic 3-D viewing in telenavigation tasks involving medical flexible endoscopes. Nonetheless, the increased level of depth awareness provided by stereo viewing is remarkable, which facilitates endoscope teleguide, teleexploration, and teleintervention, leading to accurate navigation and faster decision-making. This paper assesses S3D in medical endoscopic teleoperation. We evaluate the usability of a flexible stereoscopic bronchoscope. Twenty test users are asked to teleguide a virtual endoscope, which operates in a realistically simulated bronchus environment under different viewing conditions and displays. The evaluation involves seven systems (from laptops to wall screen and head-mounted display), four approaches to stereo viewing (colored Anaglyph, polarized filters, shutter glasses, and separated displays), and five types of display technologies (digital light processing, cathode ray tube, liquid crystal display, light-emitting diode (LED), and organic LED). The results show a strong improvement in users´ performance when the endoscope-camera view is (depth-) enhanced by stereo viewing. Users´ performance and appreciation may vary in different systems, which is also commented in this paper. This study supports system designers in making informed decisions.