Machine Intelligence Laboratory

Cambridge University Department of Engineering

Dr Graham Treece, Department of Engineering

F-GMT11-1: Computer graphics: multi-parameter visualisation on a 3D surface.

The most straightforward way to show a single parameter mapped over a surface is to use colour to display it: here the colour shows the thickness of the outer layer of bone (cortex).

You could also display the same information as two surfaces (inner and outer) rendered slightly transparent. This gives a more physical sense to the data, but you can only see it at the edges.

Here we want to show two parameters: thickness, and also statistical significance. This attempt to used washed-out colours is only capable of showing binary significance values (i.e. yes or no) at the same time as thickness. What if we have more parameters we want to display? Just how much can be successfully visualised at the same time?

Hip fracture is a major issue affecting millions of people annually. We have recently been involved in research which has the potential to contribute significantly to our understanding of why hips fracture and what can be done to prevent them from doing so. This has mainly focussed on assessing various properties of the denser layer of cortical bone surrounding the less dense bone in the centre. Hence we end up with multiple parameters (for instance thickness, mass, density) which vary over the surface of the hip.

Visualising these parameters is a real challenge: even for a single parameter, we need to simultaneously display the shading of the hip surface (so that it looks 3D) as well as the variation in the parameter value over the surface. We can just about do this using colour (see above). But we frequently need to display more than one parameter: how can this best be done?

This project needs a creative individual who can think up interesting and novel ways of visualising such information and is interested in implementing these visualisations using computer graphics and computational geometry. Some examples are shown above, but there are many more possibilities.

Click here for other medical imaging projects offered by Graham Treece.