School of Engineering, RMIT University, Australia.
School of Engineering, RMIT University, Australia.
Comput Methods Programs Biomed. 2021 Mar;200:105828. doi: 10.1016/j.cmpb.2020.105828. Epub 2020 Nov 8.
Soft tissue modelling is crucial to surgery simulation. This paper introduces an innovative approach to realistic simulation of nonlinear deformation behaviours of biological soft tissues in real time.
This approach combines the traditional nonlinear finite-element method (NFEM) and nonlinear Kalman filtering to address both physical fidelity and real-time performance for soft tissue modelling. It defines tissue mechanical deformation as a nonlinear filtering process for dynamic estimation of nonlinear deformation behaviours of biological tissues. Tissue mechanical deformation is discretized in space using NFEM in accordance with nonlinear elastic theory and in time using the central difference scheme to establish the nonlinear state-space models for dynamic filtering.
An extended Kalman filter is established to dynamically estimate nonlinear mechanical deformation of biological tissues. Interactive deformation of biological soft tissues with haptic feedback is accomplished as well for surgery simulation.
The proposed approach conquers the NFEM limitation of step computation but without trading off the modelling accuracy. It not only has a similar level of accuracy as NFEM, but also meets the real-time requirement for soft tissue modelling.
软组织建模对于手术模拟至关重要。本文提出了一种新方法，可以实时逼真地模拟生物软组织的非线性变形行为。
该方法结合传统的非线性有限元方法（NFEM）和非线性卡尔曼滤波，以解决软组织建模的物理真实性和实时性能问题。它将组织力学变形定义为对生物组织非线性变形行为的动态估计的非线性滤波过程。根据非线性弹性理论，利用 NFEM 在空间上对组织力学变形进行离散化，利用中心差分格式在时间上建立非线性状态空间模型进行动态滤波。
建立了一个扩展卡尔曼滤波器来动态估计生物组织的非线性力学变形。还实现了具有触觉反馈的生物软组织的交互变形，用于手术模拟。
所提出的方法克服了 NFEM 计算步长的限制，但没有牺牲建模精度。它不仅具有与 NFEM 相似的精度水平，而且还满足软组织建模的实时要求。
