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C00002 00002	~M2BDJ25.FNT[XGP,SYS]
C00005 00003	~λ40JAFATITLE PAGE - 2.~JRFA AUGUST  1974.
C00007 00004	~λ40JCFD CONTENTS.
C00008 00005	~JVλ5JCFD DETAILED TABLE OF CONTENTS.
C00010 00006	~JCFD LIST OF BOXES.
C00011 00007	~JCFD LIST OF FIGURES.
C00013 00008	~JCFD ACKNOWLEDGEMENTS.
C00014 00009	~αINTRODUCTIONP1λ30JCFA    SECTION 0.
C00018 00010		Once acquired,   a 3-D  model can be  used to  anticipate the
C00021 ENDMK
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~M2BDJ25.FNT[XGP,SYS];
FA~FD~F1
TITLE PAGE - 1.						 AUGUST 1974.
draft - draft - draft - draft - draft - draft - draft - draft - draft

~I400,0;JC;FD           GEOMETRIC  MODELING  FOR  COMPUTER  VISION.

~I600,0;JC;FD                    BRUCE  G.  BAUMGART

~I800,0;λ17;JU;FAABSTRACT:

	The main idea of this thesis is that a 3-D geometric model of
the physical  world is an essential part  of a general purpose vision
system.  Such a model provides a goal for descriptive image analysis,
an origin for image synthesis (for  verification),  and a context for
spatial  problem solving.  Some  of the design  ideas to be presented
have been  implemented  in two  programs named  GEOMED  and CRE;  the
programs  are  demonstrated  in  situations involving  camera  motion
relative to a static world.

~λ5;H2;I1600,0;V1600,1260;I1600,0;JU;F2
	This research was supported in part  by the Advanced Research
Projects  Agency of  the  Office of  the Secretary  of  Defense under
Contract No. SD-183.

	The views  and  conclusions contained  in this  document  are
those  of the  author and  should not  be interpreted  as necessarily
representing  the official policies, either  expressed or implied, of
the Advanced Research Project Agency
or the United States Government.
~λ40;JA;FATITLE PAGE - 2.~JR;FA AUGUST  1974.
~I400,0;JC;FD GEOMETRIC  MODELING  FOR  COMPUTER  VISION.

~JCFA                      A DISSERTATION
~JCFA      SUBMITTED TO THE DEPARTMENT OF COMPUTER SCIENCE
~JCFA           AND THE COMMITTEE ON GRADUATE STUDIES
~JCFA                  OF STANFORD UNIVERSITY
~JCFA        IN PARTIAL FULFILLMENT OF THE REQUIREMENTS
~JCFA                     FOR THE DEGREE OF
~JCFA                   DOCTOR OF PHILOSOPHY

~JCFA                            BY
~JCFA                     BRUCE  G.  BAUMGART
~JCFA                        AUGUST  1974
~H4;
I310,0;V310,1260;
I460,0;V460,1260;
I1020,0;V1020,1260;
I1260,0;V1260,1260;
I1900,0;JC;FA- i -

~λ40;JCFD CONTENTS.
~JAFA

{INTRO}		0.	INTRODUCTION.
{GEM}			1.	GEOMETRIC MODELING THEORY.
{WINGED}		2.	THE WINGED EDGE POLYHEDRON REPRESENTATION.
{GEOMED}		3.	A GEOMETRIC MODELING COMMAND LANGUAGE.
{OCCULT}		4.	HIDDEN LINE ELIMINATION FOR COMPUTER VISION.
{BIN}			5.	A POLYHEDRON INTERSECTION ALGORITHM.
{CNTOUR}		6.	VIDEO IMAGE CONTOURING.
{CMPARE}		7.	IMAGE COMPARING.
{CAMERA}		8.	CAMERA AND FEATURE LOCUS SOLVING.
{VIS}			9.	COMPUTER VISION THEORY.
{CONCLU}		10.	CONCLUSION.

APPENDICES:

{REF}				REFERENCES.
{GNODES}			GEOMED NODE FORMATS.
{CNODES}			CRE NODE FORMATS.
~I1900,0;JC;FA- ii -
~JV;λ5;JCFD DETAILED TABLE OF CONTENTS.
~FA
SECTION  0.	INTRODUCTION.

SECTION  1.	GEOMETRIC MODELING THEORY.

		 1.0	Introduction to Geometric Modeling.
		 1.1	Kinds of Geometric Models.
		 1.2	Polyhedron Definitions.
		 1.3	Camera, Light and Image Modeling.

SECTION  2.	THE WINGED EDGE POLYHEDRON REPRESENTATION.

		2.0	Introduction to the Winged Edge.
		2.1	Winged Edge Link Fields.
		2.2	Perimeter Accessing.
		2.3	Edge and Face Splitting.
		2.4	Basic Polyhedron Synthesis.
		2.5	Coordinate Free Polyhedron Representation.

SECTION  3.	A GEOMETRIC MODELING COMMAND LANGUAGE.

		3.0	Introduction to GEOMED.
		3.1	Euler Routines.
		3.2	Euclidean Routines.
		3.3	Image Synthesis Routines.

SECTION  4.	HIDDEN LINE ELIMINATION FOR COMPUTER VISION.

SECTION  5.	A POLYHEDRON INTERSECTION ALGORITHM.

SECTION  6.	VIDEO IMAGE CONTOURING.

SECTION  7.	IMAGE COMPARING.

SECTION  8.	CAMERA AND FEATURE LOCUS SOLVING.

SECTION  9.	COMPUTER VISION THEORY.

SECTION 10.	CONCLUSION.
~I1900,0;JC;FA- iii -
~JCFD LIST OF BOXES.
~JAFA
SECTION  0.	INTRODUCTION.

SECTION  1.	GEOMETRIC MODELING THEORY.

SECTION  2.	THE WINGED EDGE POLYHEDRON REPRESENTATION.

SECTION  3.	A GEOMETRIC MODELING COMMAND LANGUAGE.

SECTION  4.	HIDDEN LINE ELIMINATION FOR COMPUTER VISION.

SECTION  5.	A POLYHEDRON INTERSECTION ALGORITHM.

SECTION  6.	VIDEO IMAGE CONTOURING.

SECTION  7.	IMAGE COMPARING.

SECTION  8.	CAMERA AND FEATURE LOCUS SOLVING.

SECTION  9.	COMPUTER VISION THEORY.

SECTION 10.	CONCLUSION.
~I1900,0;JC;FA- iv -
~JCFD LIST OF FIGURES.
~JAFA
SECTION  0.	INTRODUCTION.
	 0.1	Example of Descriptive Vision.
		Two objects derived from turntable pictures.
	 0.2	Example of Verification Vision - water pump parts.

SECTION  1.	GEOMETRIC MODELING THEORY.

SECTION  2.	THE WINGED EDGE POLYHEDRON REPRESENTATION.

SECTION  3.	A GEOMETRIC MODELING COMMAND LANGUAGE.

SECTION  4.	HIDDEN LINE ELIMINATION FOR COMPUTER VISION.

SECTION  5.	A POLYHEDRON INTERSECTION ALGORITHM.

SECTION  6.	VIDEO IMAGE CONTOURING.

SECTION  7.	IMAGE COMPARING.

SECTION  8.	CAMERA AND FEATURE LOCUS SOLVING.

SECTION  9.	COMPUTER VISION THEORY.

SECTION 10.	CONCLUSION.
~I1900,0;JC;FA- v -
~JCFD ACKNOWLEDGEMENTS.
~FA
The following people personally contributed to this work:

Thesis Adviser:	John Mc Carthy
Readers:		Jerome A. Feldman
			Donald E. Knuth
			Alan C. Kay

Jerry Agin, Leona  Baumgart, Tom  Binford,  Jack  Buchanan, Les  Earnest,
Tom  Gafford, Steve  Gibson, Ralph  Gorin, Tovar  Mock, Andy  Moorer,
Hans  Moravec, Richard Orban, Ted  Panofsky, Lou  Paul, Lynn  Quam,
Jeff  Raskin, Ron  Rivest, Irwin Sobel, Robert  Sproull, Ivan  Sutherland,
Dan  Swinehart, Russel  Taylor, Marty Tenenbaum, Arthur  Thomas.

~I1900,0;JC;FA- vi -
~αINTRODUCTION;P1;λ30;JCFA    SECTION 0.
~JCFD                       INTRODUCTION.
	
~JU;λ7;FM
	"For  the purpose  of  presenting my  argument  I must  first
explain the basic  premise of sorcery as don Juan presented it to me.
He said that for a sorcerer, the world of everyday life is  not real,
or out  there, as we  believe it is. For  a sorcerer, reality  or the
world we  all know, is only a description. For the sake of validating
this premise  don  Juan concentrated  the best  of  his efforts  into
leading me  to a genuine conviction  that what I held in  mind as the
world at hand was  merely a description of  the world; a  description
that had been pounded into me from the moment I was born."

~JR;FM - Carlos Castaneda. Journey to Ixtlan.


~JU;λ30;FA
	This thesis  is about  computer techniques  for handling  3-D
geometric descriptions  of the world; the world  that can be visually
perceived with a television camera.   The overall design idea may  be
characterized as  an inverse  computer graphics approach  to computer
vision. In  computer graphics, the world is represented in sufficient
detail so that the image forming process can be numerically simulated
to  generate synthetic television  images; in the  inverse, perceived
television pictures (from a real  TV camera) are analysed to  compute
detailed geometric models. For example,  the  polyhedra in figure 1.1
were   automatically  computed  by  viewing   various  objects  on  a
turntable. It is hoped,  that visually acquired 3-D  geometric models
can  be of  use  to  other robotic  processes  such as  manipulation,
navigation or recognition.

~λ9;F.{figure 0.1 two panels this page; panel A: blocks, panel B: horse}
{figure 0.2
panel A: Corrected Word Model.    Panel B: Initial World Model.
panel C: Perceived Contour Image. Panel D: Predicted Contour Image.
panel E: Perceived Video Image.   Panel F: Predicted Video.}
~λ30;Q;F.
	Once acquired,   a 3-D  model can be  used to  anticipate the
appearance  of an object in  a scene, making  feasible a quantitative
form of vision by verification (feedback vision).  For example,   the
predicted  video appearance  of  the two  machine  parts depicted  in
figure  0.2B can be computed (figure 0.2F  to 0.2D) and compared with
anaylsis of an actual video image of the parts (figure 0.2E to 0.2C).
By  comparing  the  predicted  image  with  a  perceived  image,  the
correspondence between features of the internal model and features of
the external reality can be established and a  corrected location of the
parts and the camera can be measured (figure 0.2A).

	Finally by way of introduction, I wish  to emphasive that the
kind  of vision being  attempted is  metric rather than  semantic and
that the results achieved to date are modest.  Feature classification
and recognition  in terms  of English words  is not  being attempted,
rather a system of prediction and correction beteen a 3-D world model
and a sequence of images is contemplated. The chapters of this thesis
proceed  from theory,   through implementation,  and back  to theory;
with the first five chapters dealing with modeling and the last  five
chapters dealing with vision. The theory consists  of two parts: the
first,  on geometric modeling in chapter one and the second on vision
in chapter nine.  The  implementation consists of two main programs  named
GEOMED and CRE. CRE is a solution to the problem of finding intensity
contours  in  a  sequence  of  television  pictures  and  of  linking
corresponding contours between pictures.   GEOMED is a system  of 3-D
modeling routines with  which arbitrary polyhedra may be constructed,
altered,  or viewed in perspective with hidden lines eliminated.