A new rendering algorithm based on multi-space for living soft tissue

Abstract

High fidelity display has a big impact on the user’s sense of immersion in virtual surgery. To achieve a high degree of visual realism, we propose a new subsurface scattering method, which is based on screen-space and texture-space and an improved two-layer surface reflection model, for living soft tissue rendering. The method can be described as a two-step strategy. First, the subsurface scattering in the screen space is computed. The biggest difference from traditional methods is that the back light information stored in the irradiance map of the texture space and the diffusion profile in the dipole model are used to calculate the subsurface scattering distribution formed by the light from the back of the object, which can render more rich details. Second, considering that the living soft tissues are usually covered with a thin layer of mucus, a mucus texture is mapped to the soft tissues as the second layer texture and an improved two-layer surface reflection model is proposed to render the mucus. Moreover, to show the viscosity and smoothness of the mucus, the calculation of highlight component is used in our model, which further enhances the reality of living soft tissue. Experimental results show that our method outperforms the two traditional methods of subsurface scattering based on texture space and screen space, and the rendering time of the proposed two-layer surface reflection model is 2/3 of that of the traditional model. We conducted a survey on the fidelity of soft tissues rendered using different algorithms, and the professional surgeons (60%-85%) thought that the rendered soft tissue with our method is more consistent with the characteristics of the in vivo soft tissues under a real surgical scene.