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.