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On the road to the 4-Gpixel camera

Posted: 10 Nov 2005 ?? ?Print Version ?Bookmark and Share

Keywords:graham flint? gigapxl project? 4gpixel camera?

As a physicist who has always been fascinated with cameras and photography, Graham Flint has applied his skills to information display, designing cameras for applications that have ranged from Cold War era espionage to the Hubble Space Telescope.

Now semiretired, Flint has turned his talents to the Gigapxl Project, which brings together cutting-edge photographic optics, film technology and digital processing to create wide-angled photographs of landscapes that contain unprecedented amounts of information. Flint detailed the project at the recent PopTech Conference here.

Back in 2000, it was obvious to Flint that digital cameras with resolution in the 10-megapixel range would become commonplace within a few years. On the other hand, it was unlikely that digital cameras with resolutions approaching 100 Mpixels would be available soon. "As a consequence, we felt it likely that film-based, large-format photography would for the time being remain unchallenged. With this in mind, we have concentrated on the application of ultrahigh-resolution techniques to the field of large-format photography," said Flint.

Flint and his team concluded that, consistent with the largest practicable roll of film (9 x18 inches), they could expect to achieve a resolution equivalent to 1,000 Mpixels. Although recent improvements have increased that number to nearly 4,000 Mpixels, the Gigapxl name stuck.

Flint explained that a minimum of 8 square inches of print area is needed to convey the information contained in a 1-Mpixel image. For a 1,000-Mpixel picture, the minimum print area becomes 50 square feet. Thus for a 4,000-Mpixel picture, the print would have to be 10 x 20 feet. At the same time, the sharpness of the image when viewed up close should match that of a 4 x 6-inch print from a 3-Mpixel digital camera.

"The information content of a Gigapxl print can be compared to that available in a real-world scene that is viewed through a pair of 6x binoculars" if the viewer is looking at a 1,000-Mpixel image and "twice this power at 4,000 Mpixels," said Flint.

Besides dealing with issues related to lenses, formats and film, Flint and his team had to find ways to transform images on film into prints that conveyed the maximum amount of information to the viewer. Contact printing was out of the question, since the fineness of detail in a contact print far exceeds the acuity of the unaided human eye. And even the best enlarging lenses cannot provide imagery in the 1,000-Mpixel range without loss of contrast relative to the original negative. The team concluded that it had to use high-resolution digital scanning together with some form of digital printing.

The team used a four-step process for its photos of landscapes, converting the information contained in a distant scene to a digital DVD file. The four steps involve transmission through the atmosphere, image formation by way of a lens, recording of an image on film and digitization of that image by a scanner.

Reconnaissance design

The design of the Gigapxl camera was based on earlier, 9 x 18-inch military reconnaissance cameras. The camera body and a fully loaded film magazine that is coupled to the camera weigh almost 72 pounds. With the addition of the necessary heavy-duty tripod and two 20-inch wire-spoke wheels, the total weight increases to 115.5 pounds. "Except when negotiating hiking trails with steep and sustained grades, the effort required to pull the assembly is little more than that associated with a golfer's caddie cart," said Flint.

The resulting photographs are many times sharper than conventional ones. Flint explained that in the real world, as a person moves toward an object, the image remains sharp; the object is simply seen in finer and finer detail. "Walking toward an apple tree, for example, we see from a distance its overall shape and color; maybe using that information to recognize it as a fruit tree.

As the distance closes, we note first the presence, then the shape of its fruit. By this time, we know that it's an apple tree. Closer yet, and we see the textured coloring of its apples; perhaps now having enough information to guess at their variety," explained Flint, adding that as one moves closer to an object, this accumulation of information is taken for granted.

"As we approach a large photographic print, however, this is not what happens; the reason being that conventional photographic prints need only provide a resolution that is consistent with a general appearance of sharpness at what is referred to as the 'normal' viewing distance. As a consequence, when we move toward a large conventional print, the sense of realism that may be invoked at a distance is diminished, rather than enhanced," said Flint.

But a Gigapxl print will still look sharp to a viewer, even at closer and closer range: A print of carefully selected dimensions provides uncom promised sharpness at any viewing distance. Flint said that an ideal Gigapxl print is one that combines the greatest possible enlargement ratio with the close-up appearance of perfect sharpness.

Flint gave an example that put the difference between a conventional and Gigapxl print into perspective. Whereas a person might look at a conventional print image of a real-world scene from a fixed location, without the aid of a magnifier, Flint said, a Gigapxl print images a real-world scene that a viewer would be able to explore with binoculars.

All prints have used Kodak Professional Digital III color paper. Flint said that Kodak has agreed to produce this rare film for his project for as long as he needs it.

Flint's partner, Catherine Ayes, has high expertise in the use of all aspects of both Adobe Photoshop and the pigment ink printing required for ultrahigh-resolution imagery. In work conducted with software engineers at Adobe, Gigapxl's multigigabyte files were used to train the latest versions of Photoshop to handle ever-increasing file sizes.

The team's ultimate goal is to draw a portrait of the United States and Canada through a collection of ultrahigh-resolution photographs. With the project now in its fifth year, the team has made trips to 51 states and Canadian provinces. During 2004-2005, the team members have traveled more than 50,000 miles over 246 days. More than 589 locations, many represented by multishot panoramas, have been photographed. Some of the nearly 1,200 images that have been collected so far can be viewed at www.gigapxl.com.

- Nicolas Mokhoff

EE Times





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