Physical Simulations

Haptic Palpation for Medical Simulation in Virtual Environments

by Sebastian Ullrich

Ullrich S & Kuhlen T: “Haptic Palpation for Medical Simulation in Virtual Environments”, In IEEE Transactions on Visualization and Computer Graphics. 2012, April. 18(4):617-625. IEEE Press. Best Paper Award.

Palpation is a physical examination technique where objects, e.g., organs or body parts, are touched with fingers to... more Palpation is a physical examination technique where objects, e.g., organs or body parts, are touched with fingers to determine their size, shape, consistency and location. Many medical procedures utilize palpation as a supplementary interaction technique and it can be therefore considered as an essential basic method. However, palpation is mostly neglected in medical training simulators, with the exception of very specialized simulators that solely focus on palpation, e.g., for manual cancer detection. In this article we propose a novel approach to enable haptic palpation interaction for virtual reality–based medical simulators. The main contribution is an extensive user study conducted with a large group of medical experts. To provide a plausible simulation framework for this user study, we contribute a novel and detailed interaction algorithm for palpation with tissue dragging, which utilizes a multi–object force algorithm to support multiple layers of anatomy and a pulse force algorithm for simulation of an arterial pulse. Furthermore, we propose a modification for an off–the–shelf haptic device by adding a lightweight palpation pad to support a more realistic finger grip configuration for palpation tasks. The user study itself has been conducted on a medical training simulator prototype with a specific procedure from regional anesthesia, which strongly depends on palpation. The prototype utilizes a co–rotational finite element approach for soft tissue simulation and provides bimanual interaction by combining the aforementioned techniques with needle insertion for the other hand. The results of the user study suggest reasonable face validity of the simulator prototype and in particular validate medical plausibility of the proposed palpation interaction algorithm.

An Adaptive Multiresolutional Approach for Interactive Simulation of Cloth

by Mark Wewetzer

Augmented Reality and Rigid Body Simulation for Edutainment

by Raphael Grasset

Philip Buchanan, Hartmut Seichter, Mark Billinghurst, Raphaël Grasset
Advanced in Computer Entertainment Technology (ACE 2008), 2008.

Bimanual Haptic Simulator for Medical Training: System Architecture and Performance Measurement

by Sebastian Ullrich

Ullrich S, Rausch D & Kuhlen T: "Bimanual Haptic Simulator for Medical Training: System Architecture and Performance Measurement", In JVRC11: Joint Virtual Reality Conference of EGVE - EuroVR. Nottingham, UK. 2011, September. pp. 39-46. Eurographics Association.

In this paper we present a simulator for two-handed haptic interaction. As an application example, we chose a medical... more In this paper we present a simulator for two-handed haptic interaction. As an application example, we chose a medical scenario that requires simultaneous interaction with a hand and a needle on a simulated patient. The system combines bimanual haptic interaction with a physics-based soft tissue simulation. To our knowledge the combination of finite element methods for the simulation of deformable objects with haptic rendering is seldom addressed, especially with two haptic devices in a non-trivial scenario. Challenges are to find a balance between real-time constraints and high computational demands for fidelity in simulation and to synchronize data between system components. The system has been successfully implemented and tested on two different hardware platforms: one mobile on a laptop and another stationary on a semi-immersive VR system. These two platforms have been chosen to demonstrate scaleability in terms of fidelity and costs. To compare performance and estimate latency, we measured timings of update loops and logged event-based timings of several components in the software.

PICO: Interactive Computer Program for Rigid Object Simulation Based on Physics

by isaac rudomin