Scott Cohen



Background
I received my undergraduate B.S. degrees in Mathematics and Computer
Science from Stanford University in June 1993. The next year I enrolled in
the Ph.D. program in Computer Science at Stanford. I received
my M.S. in Computer Science from Stanford in January 1996, and my
Ph.D. in Computer Science from Stanford in June 1999. My advisor was
Professor Leonidas Guibas. I spent 10 years
at Stanford (!), 4 years as an undergrad and 6 years as a graduate student.
When I started the Ph.D. program I was heavily involved in scientific
computation. I spent the first two summers of the program working at
Lawrence Livermore National Laboratory on the
CVODE ordinary
differential equation solver. Since then, my interests have shifted
to computer vision. I was a member of the
Stanford Vision Laboratory (SVL) in the
Image Retrieval Systems Group (IRS) group. My research focused
on building contentbased image retrieval systems that find color and shape
query patterns within database images.
I will be working in the Graphics Technology Group at
Adobe starting July 1999.
Research
Brief descriptions of my Stanford research projects are given below.

 Finding Color and Shape Patterns in Images
The goal of this project is a system which efficiently retrieves
database images that contain a given query pattern or
a region similar to the query. The proposed solution is
the SEDL (Scale Estimation for Directed
Location) image retrieval system. The SEDL framework is
general enough to find both color and shape patterns. It has
been successfully applied to find (1) color patterns in a
database of product advertisements with product logos as queries,
and (2) shape patterns in a database of Chinese characters.





 Computing the Earth Mover's Distance under Transformations
This project aims at extending the Earth Mover's Distance (EMD) between
distributions to be invariant to some given set of distribution
transformations. This problem is motivated by examples from contentbased
image retrieval. A monotonically convergent iteration is given, although
the iteration may converge to only a locally optimal transformation.
Specific cases are identified in which a globally optimal transformation
can be computed directly, without the aid of our iteration.
A gentle introduction to the EMD is also included.

Click on a project logo for more information.
Publications
 S. Cohen.
Finding Color and Shape Patterns in Images.
Technical Report STANCSTR991620, May 1999.
(ps,
pdf)
This tech report is my Ph.D. thesis.
Here is just the abstract (ps,
pdf) and just the table of
contents (ps,
pdf).
There are 274 pages,
numbered ixviii for the title page, abstract, table of contents, etc.,
and 1256 for the main document.
 S. Cohen and L. Guibas.
The Earth Mover's Distance under Transformation Sets.
Proceedings of the 7th IEEE International Conference on
Computer Vision, September 1999. To appear.
(ps 9.9MB,
ps.gz 4.3MB,
pdf 315KB)
 S. Cohen and L. Guibas.
The Earth Mover's Distance: Lower Bounds and Invariance under
Translation.
Technical Report STANCSTR971597, November 1997.
(ps,
pdf)
 S. Cohen and L. Guibas.
Shapebased Image Retrieval Using Geometric Hashing.
Proceedings of the ARPA Image Understanding Workshop,
669674, May 1997.
(ps,
pdf)
 S. Cohen and C. Tomasi.
Systems of Bilinear Equations.
Technical Report STANCSTR971588, April 1997,
with Matlab code.
(ps,
pdf)
 S. Cohen and L. Guibas.
Partial Matching of Planar Polylines
Under Similarity Transformations.
Proceedings of the Eighth Annual ACMSIAM Symposium on
Discrete Algorithms,
777786, January 1997.
(ps,
pdf)
 S. Cohen and A. Hindmarsh.
CVODE, a Stiff/Nonstiff ODE Solver in C.
Computers in Physics,
10(2):13843, MarchApril 1996.
(ps,
pdf)
 S. Cohen and L. Guibas.
Shapebased Illustration Indexing and Retrieval 
Some First Steps.
Proceedings of the ARPA Image Understanding Workshop,
12091212, February 1996.
(ps,
pdf)
 S. Cohen and A. Hindmarsh.
CVODE User Guide.
Lawrence Livermore National Laboratory report UCRLMA118618,
September 1994.
(ps,
pdf)
Other Works
 S. Cohen.
Measuring Point Set Similarity with the Hausdorff Distance:
Theory and Applications.
Ph.D. qualifying exam. November 1995.
(ps,
pdf)
 S. Cohen.
Cyclic Reduction.
Undergraduate math thesis. June 1993.
(ps,
pdf)
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scohen@cs.stanford.edu