PASCAL - Pattern Analysis, Statistical Modelling and Computational Learning

Modelling motion primitives and their timing in biologically executed movements
Ben Williams, Marc Toussaint and Amos Storkey
Advances in Neural Information Processing Systems 20 2008.

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Biological movement is built up of sub-blocks or motion primitives. Such primitives provide a compact representation of movement which is also desirable in robotic control applications. We analyse handwriting data to gain a better understanding of primitives and their timings in biological movements. Inference of the shape and the timing of primitives can be done using a factorial HMM based model, allowing the handwriting to be represented in primitive timing space. This representation provides a distribution of spikes corresponding to the primitive activations, which can also be modelled using HMM architectures. We show how the coupling of the low level primitive model, and the higher level timing model during inference can produce good reconstructions of handwriting, with shared primitives for all characters modelled. This coupled model also captures the variance pro?le of the dataset which is accounted for by spike timing jitter. The timing code provides a compact representation of the movement while generating a movement without an explicit timing model produces a scribbling style of output.

EPrint Type:Article
Project Keyword:Project Keyword UNSPECIFIED
Subjects:Computational, Information-Theoretic Learning with Statistics
User Modelling for Computer Human Interaction
Learning/Statistics & Optimisation
Theory & Algorithms
ID Code:3387
Deposited By:Amos Storkey
Deposited On:09 February 2008

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