clarke@csri.toronto.edu (Jim Clarke) (06/17/88)
(SF = Sandford Fleming Building, 10 King's College Road)
(GB = Galbraith Building, 35 St. George Street)
SUMMARY:
GRAPHICS AND INTERACTION SEMINAR, Tuesday, June 21, 3 pm, GB120 -- Paul Borrel:
"Interactive Design with Sequences of Parameterized Transformations"
THEORY SEMINAR, Monday, June 27, 11 am, GB244 -- Joan Boyar:
A.I. SEMINAR, Monday, June 27, 3 pm, SF1101 -- Allen M. Waxman:
"CONVECTED ACTIVATION PROFILES: Receptive Fields for Real-Time
Measurement of Short-Range Visual Motion"
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GRAPHICS AND INTERACTION SEMINAR, Tuesday, June 21, 3:00 pm, GB120
Paul Borrel
Laboratoire d'Automatique et de Microe'lectronique de Montpellier - France
Currently on Sabbatical at IBM Watson Research Center
``Interactive Design with Sequences of Parameterized Transformations''
We present a paradigm for capturing the functional and relational aspects
of a design as a sequence of parameterized unevaluated operations, which
may, for example, correspond to the individual steps of a manufacturing
process. A sequence that can transform a wide variety of models in a
manner consistent with the user's intentions can be specified interac-
tively using a single model as an example. The execution of a sequence
transform a particular model produces a result which may be interro-
gated to detect constraint violations and to locate operations responsi-
ble for creating or modifying specific features. An experimental implemen-
tation in an object oriented environement is described.
THEORY SEMINAR, Monday, June 27, 11:00 am, GB244
Joan Boyar
University of Chicago
We define a new structured and general model of computation: circuits
using arbitrary fan-in arithmetic gates over the characteristic-two
finite fields. These circuits have only one input and one output. We
show how they correspond naturally to boolean computations with n inputs
and n outputs. These circuits are equivalent to threshold circuits in
that a simulation in ei- ther direction requires only a constant blow up in
depth and a polynomial blow up in size.
The threshold circuits we consider allow arbitrary integer weights. How-
ever, we show that this is equivalent to the usual model of threshold
circuits, which is equivalent to majority cir- cuits in which any two
inputs to the same gate must come from different sources.
This is joint work with Gudmund Frandsen and Carl Sturtivant.
A.I. SEMINAR, Monday, June 27, 3 pm, SF1101
Professor Allen M. Waxman
Laboratory for Sensory Robotics
Boston University
and
MIT Lincoln Laboratory
Machine Intelligence Group
CONVECTED ACTIVATION PROFILES: Receptive Fields for Real-Time Measurement of
Short-Range Visual Motion
A new method is developed for the measurement of short-range visual motion
in image sequences by exploiting the motion of image features such as edges
and points. Each feature generates a Gaussian activation profile (or influ-
ence function) in a spatio-temporal neighborhood of specified scale around
the feature itself; this profile is then convected with the motion of the
feature. Image featural velocity estimates may then be obtained from such
dynamic activation profiles using a modification of familiar gradient tech-
niques. The resulting estimators are formulated in terms of simple ratios
of spatio- temporal filters (i.e., receptive fields) convolved with image
feature map sequences. A family of activation profiles of varying scale
must be utilized to cover a range of image velocities. In order to decide
which velocity estimate is to be accepted, the different motion channels
undergo a characteristic speed normalization before they compete. This nor-
malization scheme is consistenet with human motion perception. This mul-
tilayered processing scheme is well suited for parallel implementation. I
will show a videotape which illustrates real-time motion estimation on the
PIPE machine with feature velocity maps generated at 15 updates per second.
--
Jim Clarke -- Dept. of Computer Science, Univ. of Toronto, Canada M5S 1A4
(416) 978-4058
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