MSc Dissertation Project Opportunities 04/05


Dr C P Willis and Dr D J Paddon



L-Systems for generating Virtual Plants


Virtual plants are computer models that recreate the structure and simulate the development of plants.


Virtual plant modelling combines mathematical formalism, biological knowledge, and computer graphics techniques.


An important modelling method is based on the theory of Lindenmeyer systems (L-systems).  A fascinating aspect of this theory is the contrast between the relative simplicity of model specification and the apparent complexity, intricacy, and the visual realism of the resulting forms. L-systems allow us to:


¥        accurately recreate the structure and development of plants;


¥        show how the evolution of architectural parameters(branching angles, elongation rates, vigor of branches, etc.) affects the appearance of plants;


¥        simulate plant physiology and investigate the effects of manipulations(e.g. pruning) or different external conditions(local light microclimate, water availability, crowding) on plant development; and


¥        simulate plants not only in isolation, but growing and interacting with other plants.



Applications include:


¥   generating photorealistic virtual worlds


¥   tools for exploring desirable directions of breeding and manipulating ornamental plants for maximum visual impact.


¥   tools for simulating growth and aging in different environmental conditions


¥   teaching of botany and landscape design 



Current research problems include:


¥   simulation and visualisation of interaction between plants and their environment.


¥   modelling of aging (particularly in trees)


¥   controlling the overall shape of modelled plants


¥   realistic modelling of complex ecosystems such as forests.


MSc projects could be undertaken in any of these areas, but the work for CM50175 would include a thorough investigation of the current state of research in all aspects of L-systems, in order to identify a specific project.



Recognition of solar features


Our sun displays a wealth of interesting surface features, the most observable of which are sunspots. Sunspots have been observed for hundreds of years — Kepler saw a sunspot in 1607 (though he attributed it to a transit of Mercury across the sunÕs disk), but Chinese records of sunspots go back to 28BC.


Sunspots are generated by changes in the sunÕs magnetic field. They grow, expand, shrink and die away, usually developing into complex clusters before dwindling back into nothing. Sunspot activity rises to a maximum every 11 years, and then falls away to a minimum before rising again - the last maximum was in 2000.


Image processing can be used to take white light images of the sunÕs disk (these are widely available from sites such as NASA) and determine the boundaries of the sunspots (both umbras and penumbras, if present) and the division of the spots into related groups.


Problems with recognition of sunspots include:


¥      the complexity of many sunspots;


¥      determining whether a particular spot is Òsufficiently closeÓ to be part of a cluster;


¥      determining the classification of a particular sunspot or sunspot group.



Current research problems


¥      Improving automatic recognition of sunspots  and their groupings from white light images of the sun.


¥      Classifying recognised sunspots using one of the existing visual classification systems such as the Modified Zurich Classification


An MSc project would probably concentrate on sunspot recognition and grouping, and extend into classification if feasible.



Surface Animation


The use of computer graphics to simulate and animate biological entities has been continuously developed since computers became available to scientists. However, the animation of growing surfaces, such as flowers and leaves, has been somewhat neglected. Work has been undertaken at the University of Bath in developing the methodology for curved surface growth for entities such as flower petals, and has been extended into using genetic algorithms to control collisions between plant components (such as petals) as they grow and deform.


Scope exists for an MSc project which develops this work into a usable application program for animating the growth of plant structures, and considers further refinements in the use of genetic algorithms for the control of collisions.



Modelling Traffic Flow


The increase in traffic on our roads has led to local authorities introducing various methods to try to improve traffic flow through our towns. One particular issue is that of roundabouts. A roundabout is a form of intersection design and control which accommodates traffic flow in one direction around a central island, operates with yield control at the entry points, and gives priority to vehicles within the roundabout. Originally, all roundabouts had a simple form of yield control based on the joining traffic giving way to traffic already on the roundabout. However in recent years there has been a move towards controlling entry to and movement around, roundabouts via traffic lights. The opinion of the road designers is that traffic light control at roundabouts improves throughput of traffic. The opinion of most drivers is that it doesn't!


There is scope for an MSc project which looks at modelling traffic flow through both types of roundabout, and various combinations of the two types, to determine which is most effective. Obviously, the density of traffic flow is an important issue, especially since most traffic light controlled roundabouts tend to be in high traffic areas.  As part of the project students would have to investigate the traffic flow at local roundabouts (with and without traffic lights), so that they gain an understanding of how traffic flows through a roundabout at different densities. The project has considerable scope to provide a useful tool for road designers.



Procedural Cityscape generation


Computer games have to be highly sophisticated in their representation of virtual worlds. Much of the modelling of games worlds is crafted by hand, and is therefore a time-consuming and costly task. Procedural generation of visual data has been around for some time, and is now being applied to the generation of virtual scenary for computer games.


Recent work has considered procedural generation of complex, detailed cityscapes, developing diverse buildings, street plans etc from simple building blocks. Interestingly, some of this work has been based on L-systems.


There is considerable scope for an MSc project to explore methods of procedural generation of cityscapes and provide a procedural tool for building virtual cities.



Other Project Possibilities


There are a large number of areas in computer graphics which require further research into modelling techniques. For example, modelling of moving water, flames, atmospheric phenomena, corrosion etc.


Some projects of particular interest to us:

Image stitching

Parallel ray-tracing

Specification-based inheritance (obviously not a graphics project!)

Algorithm animation



A highly motivated student could develop a suitable project in one of these areas.