IEEE Spectrum July, 2009 - 15

careers
art fraud
forensics

An engineer helps curators
foil forgers

H

ow many engineering jobs let
you take a van Gogh off the wall
and hold it in your hands? The
kind C. Richard Johnson Jr. landed. He's
both an electrical engineering professor
at Cornell University, in Ithaca, N.Y.,
and an adjunct research fellow at the
Van Gogh Museum, in Amsterdam. As
such, Johnson says, he can "speak the
language of people on both sides."
And when the two sides talk, they
mainly talk about fraud and how to
detect it. Two years ago, Johnson
organized a conference at the museum
that brought together researchers
from Pennsylvania State University
and Princeton, in the United States
and Maastricht University in the
Netherlands. Together, they processed
high-resolution images with specially
designed signal-processing algorithms
to help sort fake van Goghs from real
ones at the brushstroke level. It was
the first time that image-processing
teams at different universities could
compare authentication approaches on
the same paintings. Another workshop
will follow next year at the Museum
of Modern Art, in New York City.
"Fraud detection is a 'sexy' topic,
which is why it was an early focus of my
activities," says Johnson. "But we're 10 to
15 years away from the computer having
any authority in it. So now my colleagues
and I are pursuing a wide variety of
issues of interest to conservators and
art historians, where signal processing
can provide assistance that reaches well
beyond just the detection of frauds."
Johnson's current focus is on
canvas thread counts-the number of
horizontal threads crossing a vertical
line 1 centimeter long-to identify
paintings from the same roll of canvas.
"Placing a questioned painting on the
same canvas roll as a painting known
to be from a particular artist supports
www.spectrum.ieee.org

painting by numbers: c. richard
johnson [left, center] uses signal-processing
algorithms to authenticate canvases believed
to be painted by van Gogh.
Photos: van gogh museum

authentication to an artist who
bought canvas in rolls, as van Gogh
often did," he says. "When canvas is
prepared with a lead white ground,
the grooves between the threads are
filled with radio-opaque material," says
Johnson. "This registers in an X-ray
as an intensity pattern that reveals
the individual threads, permitting a
calculation of the weave density." The
pattern is then analyzed with a Fourier
transform, the same technique that
radio engineers use to break down a
signal into a series of simple sine waves.
The team is distributing the
software free to museums. The Van
Gogh Museum already uses the data
generated to identify paintings from
the same canvas roll by determining
how the sections were arranged on
the roll before being cut for use.

Johnson stumbled into art as he
wandered through Berlin museums
during a college year abroad while
earning a bachelor's in electrical
engineering from Georgia Tech.
Later, while working on his Ph.D. in
EE at Stanford, he took a class in the
Dutch masters, which rekindled his
passion. In 1977, he became the first
Ph.D. student to graduate from the
university with a minor in art history.
He went straight into academia,
teaching at Virginia Tech until
1981, when he moved to Cornell.
He was named an IEEE Fellow
in 1989 for his work in digital
control and signal processing.
"This kind of research is not
something to recommend to Ph.D.
students. There are no jobs, no one's
eager to fund this, and it's career killing
for any pretenure academic," he says,
laughing. "But for me, it's like having a
backstage pass. I go to a conservation
studio and can take a van Gogh out of its
frame and examine it." -Susan Karlin
july 2009 * iEEE SpEctrum * NA

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Table of Contents for the Digital Edition of IEEE Spectrum July, 2009
