I am currently a third-year computer science Ph.D. student at Purdue University. My advisor is Voicu Popescu.
My research interest is the use of augmented and virtual reality for medical and educational applications, such as surgical telementoring.
|A Hand-Held, Self-Contained Simulated Transparent Display
Andersen D, Popescu V, Lin C, Cabrera ME, Shanghavi A, Wachs J. A Hand-Held, Self-Contained Simulated Transparent Display. ISMAR’16 – Proceedings of the IEEE International Symposium on Mixed and Augmented Reality (poster), Merida, Mexico, September 2016.
Hand-held transparent displays are important infrastructure for augmented reality applications. Truly transparent displays are not yet feasible in hand-held form, and a promising alternative is to simulate transparency by displaying the image the user would see if the display were not there. Previous simulated transparent displays have important limitations, such as being tethered to auxiliary workstations, requiring the user to wear obtrusive head-tracking devices, or lacking the depth acquisition support that is needed for an accurate transparency effect for close-range scenes.
We describe a general simulated transparent display and three prototype implementations (P1, P2, and P3), which take advantage of emerging mobile devices and accessories. P1 uses an off-the-shelf smartphone with built-in head-tracking support; P1 is compact and suitable for outdoor scenes, providing an accurate transparency effect for scene distances greater than 6m. P2 uses a tablet with a built-in depth camera; P2 is compact and suitable for short-distance indoor scenes, but the user has to hold the display in a fixed position. P3 uses a conventional tablet enhanced with on-board depth acquisition and head tracking accessories; P3 compensates for user head motion and provides accurate transparency even for close-range scenes. The prototypes are hand-held and self-contained, without the need of auxiliary workstations for computation.
|Medical telementoring using an augmented reality transparent display
Andersen D, Popescu V, Cabrera ME, Shanghavi A, Gomez G, Marley S, Mullis B, Wachs JP. Medical telementoring using an augmented reality transparent display. Surgery. 2016 Jun 30;159(6):1646-53.
Background: The goal of this study was to design and implement a novel surgical telementoring system called STAR (System for Telementoring with Augmented Reality) that uses a virtual transparent display to convey precise locations in the operating field to a trainee surgeon. This system was compared to a conventional system based on a telestrator for surgical instruction.
Methods: A telementoring system was developed and evaluated in a study which used a 1 x 2 between-subjects design with telementoring system, i.e. STAR or Conventional, as the independent variable. The participants in the study were 20 pre-medical or medical students who had no prior experience with telementoring. Each participant completed a task of port placement and a task of abdominal incision under telementoring using either the STAR or the Conventional system. The metrics used to test performance when using the system were placement error, number of focus shifts, and time to task completion.
Results: When compared to the Conventional system, participants using STAR completed the two tasks with less placement error (45% and 68%) and with fewer focus shifts (86% and 44%), but more slowly (19% for each task).
Conclusions: Using STAR resulted in decreased annotation placement error, fewer focus shifts, but greater times to task completion. STAR placed virtual annotations directly onto the trainee surgeon’s field of view of the operating field by conveying location with great accuracy; this technology helped to avoid shifts in focus, decreased depth perception, and enabled fine-tuning execution of the task to match telementored instruction, but led to greater times to task completion.
[ PDF ]
|Avoiding Focus Shifts in Surgical Telementoring Using an Augmented Reality Transparent Display
Andersen D, Popescu V, Cabrera ME, Shanghavi A, Gomez G, Marley S, Mullis B, Wachs J. Avoiding Focus Shifts in Surgical Telementoring Using an Augmented Reality Transparent Display. Medicine Meets Virtual Reality 22: NextMed/MMVR22. 2016 Apr 19;220:9.
Also presented at NextMed/MMVR22 2016.
Conventional surgical telementoring systems require the trainee to shift focus away from the operating field to a nearby monitor to receive mentor guidance. This paper presents the next generation of telementoring systems. Our system, STAR (System for Telementoring with Augmented Reality) avoids focus shifts by placing mentor annotations directly into the trainee’s field of view using augmented reality transparent display technology. This prototype was tested with pre-medical and medical students. Experiments were conducted where participants were asked to identify precise operating field locations communicated to them using either STAR or a conventional telementoring system. STAR was shown to improve accuracy and to reduce focus shifts. The initial STAR prototype only provides an approximate transparent display effect, without visual continuity between the display and the surrounding area. The current version of our transparent display provides visual continuity by showing the geometry and color of the operating field from the trainee’s viewpoint.
[ PDF ]
|Virtual annotations of the surgical field through an augmented reality transparent display
Andersen D, Popescu V, Cabrera ME, Shanghavi A, Gomez G, Marley S, Mullis B, Wachs J. Virtual annotations of the surgical field through an augmented reality transparent display. The Visual Computer. 2015 May 27:1-8.
Existing telestrator-based surgical telementoring systems require a trainee surgeon to shift focus frequently between the operating field and a nearby monitor to acquire and apply instructions from a remote mentor. We present a novel approach to surgical telementoring where annotations are superimposed directly onto the surgical field using an augmented reality (AR) simulated transparent display. We present our first steps towards realizing this vision, using two networked conventional tablets to allow a mentor to remotely annotate the operating field as seen by a trainee. Annotations are anchored to the surgical field as the trainee tablet moves and as the surgical field deforms or becomes occluded. The system is built exclusively from compact commodity-level components—all imaging and processing are performed on the two tablets.
|STAR – A System for Telementoring with Augmented Reality
Andersen D, Popescu V, Cabrera ME, Shanghavi A, Rojas Muñoz EJ, Mullis B, Marley S, Gomez G, Wachs JP, “STAR – A System for Telementoring with Augmented Reality.” IMSH 2016. San Diego, CA. 16-20 Jan 2016. Interactive Demo.
|STAR: Using Augmented Reality Transparent Displays for Surgical Telementoring
Andersen, D. “STAR: Using Augmented Reality Transparent Displays for Surgical Telementoring.” Eskenazi Health 22nd Annual Trauma & Surgical Critical Care Symposium. Indianapolis, IN. 16 Oct 2015. Conference Presentation.
[ Slides ]
- NSF GRFP Fellowship, 2015 (three years of funding)