UCT CS Research Document Archive

Perceptual depth cues in support of medical data visualisation

Lyness, Caleb Alexander (2004) Perceptual depth cues in support of medical data visualisation. MSc, Department of Computer Science, University of Cape Town.

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This work investigates methods to provide clinically useful visualisations of the data produced by an X-ray/CT scanner. Specifically, it examines the use of perceptual depth cues (PDCs) and perceptual depth cue theory to create effective visualisations.

Two visualisation systems are explored: one to display X-ray data and the other to display volumetric data. The systems are enhanced using stereoscopic and motion PDCs. The presented analyses show that these are the only possible enhancements common to both systems. The theoretical and practical aspects of implementing these enhancements are presented.

Volume rendering techniques are explored to find an approach which gracefully handles poorly sampled data and provides the interactive rendering needed for motion cues. A low cost real time volume rendering system is developed and a novel stereo volume rendering technique is presented. The developed system uses commodity graphics hardware and Open-GL.

To evaluate the visualisation systems a task-based user test is designed and implemented. The test requires the subjects to be observed while they complete a 3D diagnostic task using each system. The speed and accuracy with which the task is performed are used as metrics. The experimental results are used to compare the effectiveness of the augmented perceptual depth cues and to cross-compare the systems.

The experiments show that the user performance in the visualisation systems are statistically equivalent. This suggests that the enhanced X-ray visualisation can be used in place of CT data for some tasks. The benefits of this are two fold: a decrease in the patient's exposure to radiation and a reduction in the data acquisition time.

EPrint Type:Electronic Thesis or Dissertation
Keywords:volume rendering, stereopsis, stereo, perceptual depths cues, lodox, x-rays, volumetric data
Subjects:I Computing Methodologies: I.3 COMPUTER GRAPHICS
ID Code:138
Deposited By:Lyness, Caleb Alexander
Deposited On:05 July 2004