Automated Medical Avatar Animation for Warfighter Mission Simulation.

Abstract

BACKGROUND\nVirtual representations of human internal anatomy are important for military applications such as protective equipment design, injury severity prediction, thermal analysis, and physiological simulations. High-fidelity volumetric models based on imaging data are typically in static postures, and difficult to utilize in simulations of realistic mission scenarios. This study aimed to investigate a hybrid approach to reposition medical avatars that preserves internal anatomy but allows rapid repositioning of full 3D meshes.\n\n\nMETHODS\nA software framework was developed that accepts a medical avatar in a 3D tetrahedral mesh format representing 72 organs and tissues with an articulated skeleton. The skeleton is automatically resized and associated to the avatar using rigging and skinning algorithms inspired by computer animation techniques. Military relevant motions were used for animations. A motion retargeting algorithm was implemented to apply animation to avatars of various sizes, and a motion blending algorithm was implemented to smoothly transition between movements. These algorithms were incorporated into a path generation tool that accepts initial, intermediate, and final coordinates of a multi-segment action along with the specific motion for each segment to synthesize a realistic compound set of movements comprising the animation.\n\n\nRESULTS\nThe developed pipeline for dynamic repositioning of medical avatars was demonstrated. Various complex motions were automatically animated. Retargeting was demonstrated on models of varying sizes. Movements along a path were animated to demonstrate smooth motion transitions. Animation of the full 3D avatar mesh ran in real-time on a standard desktop PC. The repositioning algorithm successfully preserved shape and volume of rigid structures such as bone.\n\n\nCONCLUSIONS\nThe developed software leverages techniques from various disciplines to create a hybrid approach enabling real-time 3D mesh repositioning appropriate for use in simulated military missions using avatars containing a complete anatomy representation. The workflow is largely automated, enabling rapid evaluation of new mission scenarios.\n\n\nLEVEL OF EVIDENCE\nN/A.