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C00004 00003 ABSTRACT:
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C00016 00005 II. MILESTONES CHART.
C00036 00006 III. CONTRIBUTION TO THE ORIGINAL PROPOSAL.
C00038 00007 IV. BUDGET.
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Research Proposal Amendment Submitted to
THE NATIONAL SCIENCE FOUNDATION
for
GEOMETRIC MODELING FOR ASSEMBLY SYSTEMS.
Amending the proposal
EXPLORATORY STUDY OF COMPUTER INTEGRATED ASSEMBLY SYSTEMS.
by
THE STANFORD ARTIFICIAL INTELLIGENCE LABORATORY
MAY 1974
Computer Science Department
School of Humanities and Sciences
STANFORD UNIVERSITY
Stanford, California
ABSTRACT:
This is a request for an additional grant of $30,000 to
support a nine month research program in 3-D geometric modeling for
the visual feedback and manipulation planning portions of the
exploratory study of computer integrated assembly systems.
CONTENTS:
I. TECHNICAL WRITEUP.
II. MILESTONES CHART.
III. CONTRIBUTION TO ORIGINAL PROPOSAL.
IV. BUDGET.
I. TECHNICAL WRITEUP.
We propose to represent and simulate solid objects in a
computer for the sake of visual feedback and manipulation planning.
The project has three phases: acquistion of 3-D models, use of the
models for verification vision and use of the models for collision
avoidance in planning arm trajectories. Models are aquired both by
manually drawing the objects using a 3-D geometric editing program;
or by automatically analysing sequences of television pictures of the
given object. Once acquired, a 3-D model can be used to anticipate
the appearance of an object or a scene of objects by means of an
(existing) hidden line eliminator which generates both video and line
drawing images in a form internally useful to the computer. With good
predicted images available, a quantitative form of vision by
verification (visual feedback) becomes feasible (figure 1, all
figures follow this sectin). In particular the location and extent of
occlusion and shines in a image is anticipated so that the
characteristics of unknown features can be measured with less
confusion. Finally, routines will be developed for detecting and
avoiding collisions between objects during simulated manipulations.
The final form of this work will be that of a geometric
modeling system that is accessible through a command langauge which
will be a language extension to existing languages such as SAIL
(ALGOL) and LISP. The command language will have routines for object
generation, Euclidean transformations, metrics, I/O, mechanics,
image synthesis and image analysis. The image processing primitives
will be included as a subset of the vision language being developed
under the original proposal by Binford and Russel.
The proposed work is based on the following ideas and work
already done:
i. Explicit 3-D Object Representation.
The presently implemented explicit object representation is
based on polyhedron models of solid rigid objects. A simple object
is defined by a surface shell of vertices, edges and faces that
satisfy the Euler equation, V - E + F = 2. Such polyhedra are
combined to form compound objects. Curved objects are represented by
approximating them using a polyhedron composed of a sufficient number
of flat polygonal faces.
ii. Object Generation from Physical Description.
A convenient way of making an explicit computer model of an
object is to simulate the process of building the object. That is,
the description of how to build an object is an implicit
representation of the object. For example it is easier to describe
Figure 2 as a dodecahedron with a regular five pointed star shaped
hole cut through it, than it is to draw the figure with a light pen
or to list the loci of its vertices.
iii. Language Extension.
Rather than developing new languages for geometric modeling,
we believe it is best to extend the old languages: ALGOL and LISP.
The elements of language extension include new data types for the
language, general low level primitives for manipulating the new data
types, and a convenient set of higher level operations. The division
of the work into high level operations defined in terms of low level
primitives is an important part of the design because it isolates the
data structure manipulating code.
iv. Object Representation from Physical Measurement,
Another way to get an explicit computer model of an object is
to derive it from measurements made on an actual physical object, 2-D
drawing, or picture. For example, the physical object might be a
clay model of the thing being designed. We believe that only the lack
of appropriate software is preventing the use of television cameras
as an inexpensive, accurate, and automatic means of entering
graphical data into a computer. (Figure 3)
vi. Mechanical Simulation.
Information, such as the degrees of freedom of motion, is
included in the object description and can be used to get pictures of
objects in different positions. This is demonstrated in the A.I.
Laboratory's flip book animation of a mechanical arm turning a block
over. Mechanical information can also be used to constrain the shape
of a part in its desired place, or to find the space potentially
occupied by a moving part.
vii. Photometric Simulation.
Photometric information such as the location and nature of
light sources and the light scattering properties of the objects'
surfaces can be included in the model and used to compute the actual
appearance of solid opaque objects. (Figure 4)
II. MILESTONES CHART.
The goals of the proposed project are summarized in the following list:
Items partially in hand.
1. Representation of solid rigid three-dimensional polyhedra.
2. Language extension of geometric primitives.
3. Language extension of object building operations.
4. Polyhedral object hidden line (and surface) eliminator.
5. Geometric editor.
Items within nine month work.
6. Routines for collision avoidance.
7. Routines for verification vision.
8. Video acquisition of three-dimensional objects.
9. Mechanical simulation and animation.
10. Photometric simulation - shadows and light sources.
In Chart form:
1974 1975
JUL AUG SEP OCT NOV DEC JAN FEB MAR
________________________________________________________________________
| | | |
|←←←←←←← GEOMETRIC MODELING SYSTEMS WORK →→→→→→→→→→→→→→→→→→→→→→→→→→→→→→→|
| | | |
|←←← COLLISION AVOIDANCE →→→→→→→→→→ | |
| | ←←← VERIFICATION VISION →→→→→→→→→→→→→|
|←←← MECHANICAL SIMULATION →→→→→→→→ | |
| | ←←← VIDEO AQUISITION →→→→→→→→→→→→→→→→|
| | | |
| | ←←← PHOTOMETRIC SIMULATION →→→→→→→→→→|
|_______________________|_______________________|_______________________|
JUL AUG SEP OCT NOV DEC JAN FEB MAR
1974 1975
III. CONTRIBUTION TO THE ORIGINAL PROPOSAL.
The main contribution of this amendment to the original
proposal would be to add an existing 3-D polyhedral geometric
modeling system to the already supported work on 2-D vision,
spine-cross section models and semantic models. The main advantage of
a polyhedral model is that surfaces are explicitly represented so
that appearance and collision can be simulated. The work of Mr.
Baumgart, was mentioned in the original proposal; but was to have
been supported on another grant.
IV. BUDGET.
RESEARCH GRANT PROPOSAL BUDGET
NINE MONTHS BEGINNING 1 JULY 1974
Requested University Total
Budget Category From NSF Contribution Costs
------------------------------------------------------------------------
I. SALARIES & WAGES:
McCarthy, John, $ 0 $ 0 $ 0
Professor,
Principal Investigator
Baumgart, Bruce G., 10,693 107 10,800
Research Associate
9 months FTE
__________, 4,351 44 4,395
Student Research Ass't.,
50% Acad. Yr., 100% Summer
6 months FTE
_______ _______ _______
TOTAL SALARIES $15,044 $ 151 $15,195
II. STAFF BENEFITS:
7-1-74 to 8-31-74 @ 17.0% 568 6 574
9-1-74 to 3-31-75 @ 18.0% 2,106 21 2,127
_______ _______ _______
$ 2,674 $ 27 $ 2,701
III. EQUIPMENT RENTAL (IBM DISK) $ 2,000 $ 20 $ 2,020
IV. EXPENDABLE MATERIALS & SERVICES:
A. Telephone Service
B. Office supplies $ 190 $ 2 $ 192
V. PUBLICATION COSTS: $ 500 $ 5 $ 505
VI. TOTAL DIRECT COSTS:
(Items I thru V) $20,408 $ 205 $20,613
VII. INDIRECT COSTS:
On Campus - 47% of NTDC $ 9,592 $ 96 $ 9,688
VIII. TOTAL COSTS:
(Items VI + VII) $30,000 $ 301 $30,301