Real-time visualisation within the multimod application framework

This paper gives an overview of real-time visualisation algorithms developed under the EC-funded project Multimod to support a novel paradigm for the virtual representation of musculo-skeletal structures. These algorithms are fully integrated into the Multimod Application Framework (MAF), an open-source freely-available software framework for the rapid development of medical visualisation applications. MAF is based on the Visualisation Toolkit (VTK) and other specialised toolkits, e.g. for image registration and segmentation, collision detection or numerical computation. MAF provides a range of high-level components that can be easily combined for rapid construction of visualisation applications that support synchronised views. The majority of algorithms available within the standard underlying MAF toolkits were frequently either too slow or too general for our purposes. We have thus implemented computationally efficient versions of existing algorithms, e.g. for surface and volume rendering, and more importantly, developed new techniques, e.g. for X-ray rendering and designing volume rendering transfer functions. To achieve interactive rendering we have employed a scheme for space partitioning. The emphasis is on exploiting the characteristics of medical datasets (e.g. density value homogeneity) but further utilising the hardware-accelerated capabilities of modern graphics cards. In this context, calculations are moved into hardware as appropriate while avoiding dependency on specialised features of particular manufacturers so as to ensure real code portability.