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How the Interactive Vietnam Veterans Memorial was created on Fold3.

Peter Krogh and Darren Higgins Studio Photographer Peter Krogh and Darren Higgins

Krogh (left), a photographer who has worked with National Geographic and is widely known as a digital imaging expert, paired with Higgins to create a single "computational photograph" of the Memorial. Six computers stitched 1,494 images together. Total production time: Five months.

Step 1: Photograph every inch of The Wall

A total of 6,301 images were taken of the East and West walls

After getting permission from the National Park Service to photograph the Memorial, Krogh and his team immediately faced two major challenges:

First, the black granite was highly polished and reflective surface. Black boards were held by assistants to remove reflections as each of the 140 panels were meticulously photographed. A total of 6,301 images were taken of the East and West walls (493 feet, 4 inches).

Second, we wanted each name to be highly readable and nearly as big on a computer screen as it was at the actual site. Because of regulations at the Memorial, Krogh was unable to temporarily remove the short chain fence in front of The Wall for a better shot.

Instead he had to photograph The Wall just like any other visitor—by hand without any special equipment or tripods.

Remarkably, he was able to provide us with an image better than we could have imagined.

Step 2: Create the Fold3 "Giga" Viewer

The 5 gigapixel image would require a computer with 40 gigabytes of RAM to view it.

We believed it was important to stay true to the experience of the actual Memorial and let people browse The Wall as a single image.

The problem is that image Krogh delivered was 400,000 pixels wide (460 feet if you were to view it on a computer screen big enough).

The 5 gigapixel image (about 1,000 times bigger than your average digital camera) would require a computer with 40 gigabytes of RAM to view it.

The Fold3 development team devised a way to decode the compressed image quickly into small enough "tiles" that any computer with a browser could handle.

Step 3: Read the names and connect the data

The final challenge was to correctly identify each name and its position on the Memorial image with the military data supplied by The National Archives.

To do this, our imaging team concocted a batch of smart algorithms to simplify the image and decipher each of the 58,320 names found on The Wall.

When the computers came across a questionable name, they sent it back to the team to verify along with their best guess.

Here's an example of how that worked:

OCR example

After all of the names were correctly identified and located on the image, nearly 40 megabytes of public military databases were linked.