leff@smu.UUCP (Laurence Leff) (11/15/89)
NEW MIT AI LAB PUBLICATIONS
Announcement #13
November 15, 1989
************************************************************************
Except for the Bibliographies, publications are available in hardcopy
only.
TO ORDER, specify publications number and author and enclose
a check payable to the M.I.T. Artificial Intelligence Laboratory for
the correct amount of U.S. funds. Prices of publications include
surface postage to domestic and overseas addresses.
PREPAYMENT IS REQUIRED. Please note on order if check is sent
separately.
Send orders with payment to:
Publications, Room NE43-818
M.I.T. Artificial Intelligence Laboratory
545 Technology Square
Cambridge, MA 02139 USA
For additional information:
Phone number: (617) 253-6773
Net address: Publications@ai.mit.edu
***********************************************************************
:tr 1117
:author Bror V.H. Saxberg
:asort Saxberg, B.V.H.
:title A Modern Differential Geometric Approach to Shape from Shading
:date June 1989
:pages 211
:cost $9.00
:keywords shape from shading, computer vision, differential geometry,
dynamical systems
:abstract
How the visual system extracts shape information from a single
grey-level image can be approached by examining how the information
about shape is contained in the image. This technical report
considers the characteristic equations derived by Horn as a dynamical
system. Certain image critical points generate dynamical system
critical points. The stable and unstable manifolds of these critical
points correspond to convex and concave solution surfaces, giving more
general existence and uniqueness results. A new kind of highly
parallel, robust shape from shading algorithm is suggested on
neighborhoods of these critical points. The information at bounding
contours in the image is also analyzed.
:tr 1139
:author Jason Nieh
:asort Nieh, J.
:title Using Special-purpose Computing to Examine Chaotic Behavior in
Nonlinear Mappings
:date September 1989
:pages 72
:cost $7.00
:keywords chaos, nonlinear mappings, numerical computation, computer
architecture, standard map, standard map machine
:abstract
Studying chaotic behavior in nonlinear systems requires numerous
computations in order to simulate the behavior of such systems. The
Standard Map Machine was designed and implemented as a special
computer for performing these intensive computations with high-speed
and high-precision. Its impressive performance is due to its simple
architecture specialized to the numerical computations required of
nonlinear systems. This report discusses the design and
implementation of the Standard Map Machine and its use in the study of
nonlinear mappings, in particular, the study of the standard map.
:tr 1154
:author Anya C. Hurlbert
:asort Hurlbert, A.C.
:title The Computation of Color
:date September 1989
:pages 208
:cost $9.00
:keywords color vision, image segmentation, lightness algorithms,
color constancy, learning from example, color vision - psychophysics
:abstract
This thesis takes an interdisciplinary approach to the study of color
vision, focussing on the phenomenon of color constancy formulated as a
computational problem. The primary contributions of the thesis are
(1) the demonstration of a formal framework for lightness algorithms;
(2) the derivation of a new lightness algorithm based on
regularization theory; (3) the synthesis of an adaptive lightness
algorithm using ``learning'' techniques; (4) the development of an
image segmentation algorithm that uses luminance and color information
to mark material boundaries; and (5) an experimental investigation
into the cues that human observers use to judge the color of the
illuminant. Other computational approaches to color are reviewed and
some of their links to psychophysics and physiology are explored.
:tr 1162
:author Jean-Pierre Schott
:asort Schott, J.
:title Three Dimensional Motion Estimation Using Shading Information
in Multiple Frames
:date August 1989
:pages 190
:cost $9.00
:keywords motion recovery, motion vision, 3-D structure, 3-D vision,
shape from shading, multiple frames
:abstract
A new formulation for recovering the structure and motion parameters
of a moving patch using both motion and shading information is
presented. It is based on a new differential constraint equation
(FICE) that links the spatiotemporal gradients of irradiance to the
motion and structure parameters and the temporal variations of the
surface shading. The FICE separates the contribution to the
irradiance spatiotemporal gradients of the gradients due to texture
from those due to shading and allows the FICE to be used for textured
and textureless surface. The new approach combining motion and shading
information, leads directly to two different contributions: it can
compensate for the effects of shading variations in recovering the
shape and motion; and it can exploit the shading/illumination effects
to recover motion and shape when they cannot be recovered without it.
The FICE formulation is also extended to multiple frames.
:tr 1163
:author Kenneth Man-kam Yip
:asort Yip, K.
:title KAM: Automatic Planning and Interpretation of Numerical
Experiments Using Geometrical Methods
:date August 1989
:pages 225
:cost $9.00
:keywords artificial intelligence, nonlinear dynamics, numerical
experiments, scientific computing, scientific visualization, imagistic
reasoning
:abstract
KAM is a computer program that can automatically plan, monitor, and interpret
numerical experiments with Hamiltonian systems with two degrees of freedom.
The program has recently helped solve an open problem in hydrodynamics.
Unlike other approaches to qualitative reasoning about physical system
dynamics, KAM embodies a significant amount of knowledge about nonlinear
dynamics. KAM's ability to control numerical experiments arises from the fact
that it not only produces pictures for us to see, but also {\it looks at} (sic
- in its mind's eye) the pictures it draws to guide its own actions. KAM is
organized in three semantic levels: orbit recognition, phase space searching,
and parameter space searching. Within each level spatial properties and
relationships that are not explicitly represented in the initial
representation are extracted by applying three operations -- (1) aggregation,
(2) partition, and (3) classification -- iteratively.
:tr 1170
:author Eric Sven Ristad
:asort Ristad, E.
:title Computational Structure of GPSG Models: Revised generalized
phrase structure grammar
:date September 1989
:pages 93
:cost $8.00
:keywords linguistics, complexity, GPSG, natural language,
computational structure, computational complexity
:abstract
The primary goal of this report is to demonstrate how considerations
from computational complexity theory can inform grammatical
theorizing. To this end, generalized phrase structure grammar (GPSG)
linguistic theory is revised so that its power more closely matches
the limited ability of an ideal speaker--hearer: GPSG Recognition is
EXP-POLY time hard, while Revised GPSG Recognition is NP-complete. A
second goal is to provide a theoretical framework within which to
better understand the wide range of existing GPSG models, embodied in
formal definitions as well as in implemented computer programs. An
RGPSG for English is included an appendix.