Masterpieces on view
by Doug Stewart
The Hermitage has long
ranked as one of the world's most prestigious art museums. Yet its exquisite treasures, housed in an enormous Rococo
palace in St. Petersburg, Russia, have never been as accessible to scholars and art lovers around the world as those of,
say, the Louvre.
Now IBM has joined forces with the Hermitage to begin making its vast collection available to
the public in digital form. At a gala event in St. Petersburg on June 14, State Hermitage Museum director Mikhail Piotrovsky
and William A. Etherington, IBM senior vice president and group executive, sales and distribution, announced a multiyear
partnership. Supported by a $1.6 million grant
from IBM, the project will use new
multimedia tools developed by IBM researchers in Italy, Israel, Russia and the United States to let visitors
explore in depth many of the museum's most important objects. The tools will be available both to those visiting
in person and to the many others who will visit over the Web.
"This technology allows us to make our collections much more accessible to the public," says Piotrovsky,
"while at the same time protecting the collections themselves. It also helps make education in the museum
as interesting as possible."
The museum was built in 1765 as the private treasure house of the Russian empress and connoisseur Catherine
the Great. Today, its trove of 2.5 million objects includes not only oils by Rembrandt, Rubens, Titian and
Leonardo but also 19th and 20th century masterpieces by Cézanne, Van Gogh, Matisse and Picasso.
The Hermitage project marks the most ambitious use to date of image capture technology developed by the Image
Library Applications group at IBM's Thomas J. Watson Research Center. The group has already helped create
digital archives at the National Gallery of Art in Washington, D.C., the Vatican Library and other museums.
In 1997, the Hermitage invited IBM to develop a special Image Creation Studio and to train curators in its
use. The studio relies on a sophisticated digital camera, the Pro/3000, which uses a high-resolution CCD
sensor and specially designed color filters to record artwork with superb detail and accuracy. In a single
scan, the camera may capture 30 megabytes of information. The images are later reduced in size and compressed
to more manageable sizes for downloading over the Internet and viewing on ordinary computer screens.
The Hermitage's decision to make its whole online collection available at high resolution -- instead of providing
just a few high-resolution images, as most museums do -- makes sense to Fred Mintzer, who leads the Watson group.
"At first glance, that kind of image quality might seem higher than necessary," he says, "but it must be provided
in order for the Web site visitor to begin experiencing the beauty of the art."
Online viewing and study is a key goal of the Hermitage-IBM collaboration. A dynamic new Web site, in English
and Russian, applies hardware and software from IBM labs in Santa Teresa, California, and Naples, Italy, plus
a special user interface from IBM Interactive Media in Atlanta, Georgia. Virtual visitors will soon be able
to search a database of high-resolution images using QBIC (query by image content) search technology, which
allows people to find images by describing their color or shape (see
"Querying by image content," IBM Research,
No. 3, 1996).
In many cases, visitors will be able to view objects from different angles using PanoramIX imagery, a 3-D virtual-reality
tool developed at Watson, or zoom in using Java™-based technology created at IBM's Haifa Research Laboratory.
A client-server user interface developed at Haifa makes it easy for Hermitage staff to add or update information about the
works of art. To discourage digital pirates, all of the museum's online images will be stamped unobtrusively with digital
watermarks (see "Safeguarding your image").
Entering the museum, the visitor will find English-Russian help kiosks (developed at Haifa, as was the special Java
application framework known as Jaki on which the kiosks are based). The kiosks not only will offer museum and tour
information but will provide personalized maps that trace the shortest path around the works visitors want to see.
Already in place near the museum's main entrance is an Education and Technology Center, created in partnership with
IBM's Moscow-based East Europe/Asia Education Center. Visitors can step up to one of its seven IBM workstations and
delve interactively into some aspect of the museum's vast collections -- the gospel in Western European painting,
for example.
Piotrovsky foresees a richer experience for art lovers. "Images are at the center of digital-library technology,"
he says, "but this is about more than just seeing. It is about seeing, studying, and understanding in detail the works
of art in our collections."
Doug Stewart, a freelance writer in Ipswich, Massachusetts, often writes about technology and the arts.
Safeguarding your image
By Eric J. Lerner
If you perused the last issue of
Think Research (Number 1, 1999), you unknowingly glimpsed the future of the war against picture piracy.
For embedded in the photos on pages 18
and 34 was a new type of digital watermark -- a coded pattern, too subtle for the eye to detect, that can be used to indicate who purchased the right to publish a digital image, and thereby discourage unauthorized reproduction.
The test in this magazine was meant to prove the robustness of the watermarking technology. Previous forms of digital watermarks have been easy to foil. Pirates could either detect them and remove them by digital processing, or destroy them by distorting the image. In fact, just printing the image -- which does not preserve the numeric values of the picture elements -- could eradicate earlier watermarks.
But the new watermarks hold up well, according to Gordon W. Braudaway, who developed the technique over the past two years at IBM's Thomas J. Watson Research Center. The ones in Think Research were still detectable to a computer after printing, even though the images had been cropped and reversed and their color altered.
The new approach takes advantage of the fact that a digital image consists of several million pixels, each with a given brightness defined by a single number. Every time an image owner grants permission for the use of an image, Braudaway's watermarking software generates a unique string of numbers -- one number for each pixel in the image. This sequence is known only to the owner. The numbers are multiplied in turn by the values representing the brightness of each pixel -- a step that changes the brightness so slightly as to be unnoticeable.
To detect the watermark in a published image, Braudaway's program examines a small area surrounding every pixel to determine whether the pixel is brighter or darker than the average of its neighbors. Then the pattern of brights and darks is compared statistically with the unique watermarks of authorized users. If there is a match, the authorized user can be identified.
Traceable watermarks can protect images in a variety of ways, according to Braudaway. "In some cases," he says, "an authorized user might hand out an image to other parties, who then use it without authorization. The watermark would help the image owner plug such a leak." Or suppose the watermarked image is a photo of an artwork or other object that has been photographed many times before. The watermark can help distinguish one photographer's work from another's. "Basically," Braudaway notes, "it offers evidence of ownership, even if the image has been altered."
Braudaway says the IBM watermark system is resistant equally to innocent distortions and deliberate attacks. If the image has been rotated, resized or cropped, for example, the program restores it to its original form before searching for the watermark. If a pirate has attempted to blot out the watermark by adding random "noise" to the brightness of the pixels, the program can still recover enough of the original pattern to detect the watermark.
Right now, images of artwork are being watermarked in two pilot projects: one with the Ashmolean Museum at Oxford University and the other with the Hermitage Museum in St. Petersburg, Russia. But before long, Braudaway predicts, such technology will be available to anyone who has images to protect.
Eric J. Lerner, a freelance writer
who lives in Lawrenceville, New Jersey,
is a frequent contributor to this
magazine.
