An novel method of soft tissue haptic rendering based on the spherical harmonic representation

Haptic rendering is the process of computing and generating forces in response to user interactions with virtual objects. Due to the complexity of tissue properties and interactions in human body, soft tissue haptic rendering is a challenging task. This paper presents a novel method for soft tissue haptic rendering based on spherical harmonics(SH) representation. Firstly, it gives a brief survey on the methodologies for soft tissue haptic rendering in the literature. Secondly, efficient SH representation of 3D objects, collision detection, deformation and force response algorithms are introduced. Experiment results demonstrate that the computational cost required in computing the updates and the force feedback is significantly less than that encountered in, due to the fact that in this case merely the surface mesh points are stored, and only the contactable surface is displaced as opposed to displacing both the contact surface and internal points. For a given number of facets, the spherical harmonic force calculation update rate was faster (850–1,200Hz) than the facet representation (400–900Hz).