Robotics and Automation Society
               6:00 PM, Tuesday, 15 May, 2001

                 Three-Dimensional Imaging
           Using Accordion Fringe Interferometry

                      Lyle G. Shirley
                   Dimensional Photonics


                          ABSTRACT

   Accordion Fringe Interferometry (AFI) is an innovation in
three-dimensional imaging that enables high-speed, high-
precision, three-dimensional image capture of complex
objects. AFI overcomes inherent limitations that have held
back conventional three-dimensional imaging techniques from
achieving widespread acceptance in industrial automation and
inspection applications. AFI technology is being
commercialized by a recent MIT Lincoln Laboratory spin-off
known as Dimensional Photonics. The talk will include a
demonstration of acquiring and viewing data with Dimensional
Photonics' first commercial system for three-dimensional
data capture.

   AFI achieves its performance advantage by overcoming the
major limitations of its closest relative -- structured-
light projection. Structured-light projection suffers, for
example, from a depth-of-field limitation that arises from
imaging a pattern onto the surface of the object with a
lens. AFI, on the other hand, produces an illumination
pattern with infinite depth of field by projecting
interference fringes. Consequently, AFI can handle very
complex objects without the need for stitching together
small patches. AFI also achieves improved resolution by
projecting very small interference fringes and modulating
their phase to subdivide fringes into many resolution cells.
Complex surfaces are handled by varying the size of the
interference fringes. This "accordion motion" makes it
possible to resolve all of the fringe-number ambiguities so
that the surface profile can be correctly reconstructed.

   The power of the AFI system lies in the uniqueness of the
illumination source and software algorithms, allowing it to
produce high-precision, high-density, three-dimensional
measurements with simple components. This simplicity will
ultimately lead to a low-cost system that will open up many
new applications

   AFI was recently featured on the PBS NOVA program.
Please visit

  http://www.pbs.org/wgbh/nova/sheppard/mugshot.html

to learn more about AFI technology and to see three-
dimensional imagery produced with AFI and examples of AFI
applied to forensics. AFI was also featured in an article on
three-dimensional photography in the June 2000 issue of
"Computer Graphics World". Visit http://cgw.pennnet.com and
search for "Accordion Fringe Interferometry".


                     SPEAKER BIOGRAPHY

   Dr. Lyle G. Shirley is the president of Dimensional
Photonics, which he founded in March 2000 to commercialize
the technology for three-dimensional image capture that he
and his team developed and patented at MIT Lincoln
Laboratory. He received a BS degree in physics in 1980 and
an MS in physics in 1984 from Brigham Young University.
After receiving a Ph.D. in optics from the University of
Rochester in 1998, he joined MIT Lincoln Laboratory where he
led an effort to develop novel techniques for
three-dimensional imaging and precision metrology.


                    MEETING INFORMATION

   The IEEE Robotics and Automation Society will meet on
Tuesday, May 15, 2001, at Wellesley High School at 6:00 PM
for informal discussions and for the formal presentation
between 6:30 and 7:30 PM. (Note that this is the THIRD
Tuesday of the month, making it a departure from our
tradition of meeting on the second Tuesday.)

   The group will have a no-host dinner afterwards at
Bertucci's, where more conversations can take place with the
guest speaker. The meetings are open to the general public,
and all are welcome at the dinner afterwards.

   For more information contact Bruce Levens at 508-271-1233
or send email to info@robotics-boston.org
(mailto:info@robotics-boston.org).


                         DIRECTIONS

   From Route 128, take either Route 9 or Route 16 West.
>From the junction of Routes 9 and 16, follow Route 16
(Washington Street) West past the Wellesley Hills commuter
rail station (within walking distance of the school), then
turn left onto Rice Street.  Wellesley High School is on the
left. Parking is available in a lot just beyond the school.

   For a web map showing the location of Wellesley High
School, go to the MapBlast site at

      http://www.mapblast.com/

and enter the following information in the indicated
locations:

     Street Address           50 Rice St
     City, State ZIP          Wellesley, MA

and then click on the MapBlast icon.  The resulting map can
be zoomed in or out by clicking in the balloon area on the
right.

   For more information about our section, visit our web
site at:

         http://robotics-boston.org/