Volume Rendering

Direct volume rendering is a key technique for the visualization of medical image data. It allows to display the image data as acquired by a CT or MRI in a three dimensional rendering without the need for segmentation and mesh creation. Since it displays all the available data in the volumetric data depending on a transfer function, it offers more context than mesh based visualization. Advanced techniques, such as Path Tracing, allow to simulate realistic lighting and shadowing, but often suffer from low frame rates, image noise or other restrictions with regard to interactive changes of the camera, clipping planes, or the transfer function.


AVIS (adaptive volumetric illumination sampling) is our novel direct volume rendering method that facilitates realistic lighting while allowing for interactive changes of all relevant parameters. It renders significantly faster with less noise than comparable approaches. Thus, it is perfectly suited for mixed reality.  


  • New approximative approach for advanced lighting and shadowing in DVR
  • Intelligent reduction of illumination computations
  • Selection of appropriate illumination model
  • Very fast during all interactions, above 60 fps for stereo HD images
  • Very short pre-processing time
  • No additional noise
  • Developed with Augmented Reality & Virtual Reality in mind
  • Runs on a broad range of hardware & operating systems
  • Main requirement: OpenGL support & 3D textures
  • Integration via streaming interface

AVIS-rendering of a lung CT of a COVID patient with additional AI created masks showing the lungs (blue), Ground Glass Opacities (yellow), and consolidations (red). Clipping planes can be used to explore the interior. CT data courtesy of University Medicine Oldenburg, Germany, School of Medicine and Health Sciences, University Clinic for Visceral Surgery, Pius Hospital.

Related Publications

„Adaptive Illumination Sampling for Direct Volume Rendering“. Advances in Computer Graphics. Lecture Notes in Computer Science, pp 107–118 (2020)

(Authors: Kraft V, Link F, Schenk A, Schumann C)

„A Study Comparing Adaptive Volumetric Illumination Sampling with other Volume Rendering Techniques in the Scope of Visceral Surgery“. ACM Trans. Comput. Healthcare, Submitted

(Authors: Kraft V, Schumann C, Salzmann D, Weyhe D, Zachmann G, Schenk A)