Effective volume rendering on mobile and standalone VR headsets by means of a hybrid method

Balázs Tukora

doi:10.1556/606.2020.15.2.1

Abstract

Abstract:Numerous volume rendering techniques are available to display 3D datasets on desktop computers and virtual reality devices. Recently the spreading of mobile and standalone virtual reality headsets has brought the need for volume visualization on these platforms too. However, the volume rendering techniques that show good performance in desktop environment underachieve on these devices, due to the special hardware conditions and visualization requirements. To speed up the volumetric rendering to an accessible level a hybrid technique is introduced, a mix of the ray casting and 3D texture mapping methods. This technique increases 2-4 times the frame rate of displaying volumetric data on mobile and standalone virtual reality headsets as compared to the original methods. The new technique was created primarily to display medical images but it is not limited only to this type of volumetric data.

Highlights

In the last three decades several techniques have been developed for displaying volumetric datasets
A good example of this evolution is the recent version of Visualization Toolkit, in which GPU ray casting is applied as the default volume rendering algorithm, and if it is not supported by the hardware, 3D texture mapping is chosen for interactive and Central Processing Unit (CPU) ray casting for still rendering [11]
The size of the displayed skull on the screen was set that it filled the field of vision when looked through the goggles of the headset, which is smaller than the available area on the screen, as it can be seen on Fig. 3

Summary

Introduction

In the last three decades several techniques have been developed for displaying volumetric datasets. At first volume rendering algorithms were executed by the Central Processing Unit (CPU), and after the appearance of generally programmable Graphics Processing Units GPU’s they became run as shader programs on the graphics hardver [4], [5]. The winners of this change have been the ray casting [6] and 3D texture mapping [7], [8] methods, the most popular ones to date, while some other previously dominant techniques, like the splatting [9] and shear-warp algorithm [10], though attempts were made to port them onto GPU’s, have become extinct by today. A good example of this evolution is the recent version of Visualization Toolkit, in which GPU ray casting is applied as the default volume rendering algorithm, and if it is not supported by the hardware, 3D texture mapping is chosen for interactive and CPU ray casting for still rendering [11]

Methods

Results

Conclusion