Browsing by Author "Pearce, Andrew"

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    ANIMATING SPEECH: AN AUTOMATED APPROACH .brUSING SPEECH SYNTHESISED BY RULES
    (1987-08-01) Hill, David. R.; Pearce, Andrew; Wyvill, Brian
    This paper is concerned with the problem of animating computer drawn images of speaking human characters, and particularly with the problem of reducing the cost of adequate lip synchronisation. Since the method is based upon the use of speech synthesis by rules, extended to manipulate facial parameters, and there is also a need to gather generalised data about facial expressions associated with speech, these problems are touched upon as well. Useful parallels can be drawn between the problems of speech synthesis and those of facial expression synthesis. The paper outlines the background to the work, as well as the problems and some approaches to solution, and goes on to describe work in progress in the authors' laboratories that has resulted in one apparently successful approach to low-cost animated speaking faces. Outstanding problems are noted, the chief ones being the difficulty of selecting and controlling appropriate facial expression categories; the lack of naturalness of the synthetic speech; and the need to consider the body movements and speech of all characters in an animated sequence during the animation process.
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    PRACTICAL GRAPHICS FOR 3D COMPUTER ANIMATION
    (1985-01-01) Wyvill, Brian; Jansonius, Corine; Novacek, Milan; McPheeters, Craig; Pearce, Andrew
    Presented here are a collection of practical techniques in computer graphics which are reasonably easy to implement and produce an acceptable degree of realism for a small investment in programming time. Most of these techniques are not in themselves particularly complex but refinements on well known algorithms. Taken together they form a collection of ideas which may be of interest to other workers in the field. Research in various aspects of realistic graphics and animation requires a testbed system in which to produce results from experiments with specific areas of interest. For example to test the effectiveness of a volcanic eruption manufactured from particles, it is necessary to have at least rudimentary animation infrastructure available. In this paper we describe some of the ways in which we provide this infrastructure with the limited resources available in a typical university research environment consisting of a VAX 780 running UNIX and a frame buffer. These methods have been developed during the building of a computer animation system called Graphicsland at the University of Calgary.
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    SOLID TEXTURING OF SOFT OBJECTS
    (1987-01-01) Wyvill, Geoff; Wyvill, Brian; Pearce, Andrew; McPheeters, Craig
    Since the shape of a Soft object changes in response to its surroundings, it is difficult to give a single position in space as the location of the object. Indeed objects can and do break into sub-objects dynamically. This means that you cannot map a solid texture onto such an object simply using a function of the space co-ordinates. We have taken a different approach. Our soft objects are modelled as the volume enclosed by an iso-surface of a field calculated from a set of key points. We ascribe to each key point a set of values which represent a position in an abstract texture space. Any point on the surface of an object has a field value due to each key point and this value is used as a weight in finding a weighted vector sum of these positions. This vector sum is used to select a surface specification from the texture space. These textures retain their consistency during distortion and metamorphoses of objects. A great variety of animation effects can be achieved with this process.