HP Innovation Journal Issue 03: Summer 2016 | Page 23

UNIVERSITY OUTREACH
A colorful collaboration
Purdue University and HP: Decades of imaging innovation
In our previous issue we touched on the long-standing
research collaboration HP has with Purdue University. This
25-year collaboration has paved the way for amazing
innovation in imaging, and is now setting the stage for
advancements in ambient computing technology for
home and office applications.
T
he collaboration between Purdue and
HP started in 1992. While Qian Lin was
an intern at HP Labs during her PhD
program at Stanford University, she invited
Professor Jan Allebach and his colleague
Professor Charles Bouman to give a presenta-
tion at HP Labs. Professor Allebach was Qian’s
former advisor at Purdue University when
she was working on her Master’s degree in
HP Color LaserJet Pro
Electrical Engineering. Professors Allebach
and Bouman were well-known researchers
in the area of electronic imaging and Qian
thought they would provide valuable insights
to the HP team. This was the start of a collab-
oration between Purdue University and HP
that included HP Labs, and printer divisions
in Boise, ID, Vancouver, WA, Israel (Indigo
and Scitex), and Barcelona, Spain, that has
continued through present day. Professor
Allebach himself spent six summers as a
Visiting Researcher at HP Labs, and later
did a sabbatical there. One result of this
strong engagement
with HP was Professor
Allebach’s contribution
to the development
of HP’s Color Smooth
Dither technology.
Dithering means
creating the illusion of
colors and shades by The image on the left uses the same dither matrix for all colors. The image on the
right uses Color Smooth Dither which distributes cyan, magenta, and yellow dots
varying the dots in an stochastically. This results in a less grainy appearance.
image. In printing, dith-
ering is usually called halftoning, and shades this work. Sixteen faculty members and over
of gray are called halftones. Halftoning is 60 graduate students from four different
a key component in the printing pipeline departments at Purdue have participated in
that directly affects the print this research.
image quality. While work-
Acknowledging the contributions from
ing on a research project in Purdue professors and researchers, HP en-
digital holography, Professor dowed the Hewlett-Packard Professorship in
Allebach developed an al- 2006, which is presently held by Professor
gorithm called Direct Binary Jan Allebach. The Purdue and HP collabora-
Search to design holograms. tion continues to grow in the quest to solve
During one of his summers at some of the complex problems involving
HP Labs, he collaborated with multi-disciplinary research. As an example,
Qian, a renowned researcher a new research project explores using deep
in halftone algorithms for HP learning to recognize objects in images in real
printers. Applying Jan’s direct time for ambient computing applications. 

binary search ideas to those
algorithms led them to the design of halftone
dither matrices called “Color
Smooth Dither” that were
shipped in HP Inkjet and
large format printers.
Many other technologies
developed in the collab-
oration between HP and
Purdue can be found in a
wide range HP’s printer
products. Over two dozen
patent applications have
been filed by HP to protect HP PageWide web press
Issue 3 · Summer 2016 · Innovation Journal 23