Three-Dimensional Image

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INTRODUCTION

Three-Dimensional Image, or 3-D image, flat image enhanced to impart the illusion of depth. Humans perceive the world and the objects in it in three dimensions—breadth, width, and depth. This seemingly simple phenomenon is the product of a complicated set of interactions between our eyes and our brains that is still not entirely understood. Our eyes are spaced about 6 cm (2.5 in) apart, which causes each eye to receive a slightly different image. The brain fuses these two images into a single 3-D image, enabling us to perceive depth. This way of seeing is called binocular vision, or stereoscopic vision (see Vision).

Flat images, such as illustrations, photographs, films, and graphics on a computer screen, can be manipulated with any of several techniques to create the illusion of depth. Such techniques make the objects in the images appear to pop out of the paper, film, or screen on which they appear. Once the realm of entertainment novelties, such as movies and comic books, 3-D images today have applications in medical technology, industrial design, and high-tech virtual training programs for surgeons, pilots, and astronauts.

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STEREOGRAPHS

Stereograph

A stereograph is a combination of two photographs of the same scene taken from slightly different angles. The two different perspectives mimic stereoscopic vision. When viewed through a device called a stereoscope, the two images appear as a single three-dimensional image. In the late 19th century many people in North America and Europe collected stereographs of famous sights or world events to view in stereoscopes in their own homes.

Corbis

One way to impart the illusion of depth in a photograph is to create a stereograph—a combination of two photographs of the same scene taken from slightly different angles. The slightly different perspectives mimic stereoscopic vision. One angle records the scene from the perspective of a viewer’s left eye, and the other records the scene from the perspective of the viewer’s right eye.

To appear as a single 3-D image, a stereograph must be viewed through a stereoscope, a device that simultaneously presents the left photograph to the viewer’s left eye and the right photograph to the viewer’s right eye. The brain receives each image separately and integrates them into a single 3-D image.

Late 19th Century Stereoscope

Stereoscopes create the illusion of depth in two-dimensional photographs called stereographs. A stereograph consists of two separate photographs, each taken from a slightly different angle. When viewed through a stereoscope, the two images fuse into a single, three-dimensional image. The stereoscope featured here dates from the late 19th century, a time when stereoscopes were an immensely popular form of entertainment in Europe and North America.

Blank Archives/Archive Photos

Stereoscopes were an immensely popular form of entertainment in Europe and North America in the late 19th and early 20th centuries. Photographers of stereoscopic images traveled around the world creating stereographs of popular tourist attractions and documenting important events. Enthusiasts purchased cards featuring stereographs of famous events or sights and viewed them using stereoscopes in their own homes. Prior to radio and television, stereographs were a primary form of family entertainment.

By the 1930s, stereoscopes had declined in popularity. In 1939 German-born American inventor William Gruber and American businessman Harold Graves revived public interest in stereographs when they introduced the View-Master. The View-Master is a portable stereoscope that displays several different color stereographs mounted on a revolving disk called a reel. The View-Master proved an instant and lasting success. More than one billion reels have been created for viewing in the View-Master since its introduction in 1939. Although today it is marketed as a children’s toy, the View-Master holds a special status among collectors around the world.

View-Master

The View-Master, a type of stereoscope, was introduced in 1939. The toy proved an instant and lasting success, and today it is enjoyed by adult collectors as well as children.

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The onset of World War II (1939-1945) halted development of 3-D images for entertainment purposes, but militaries in many countries used stereographs in aerial reconnaissance. Camouflaged weapons and structures were difficult to see in conventional aerial photographs, while aerial stereographs enabled military personnel to see through the camouflage and recognize hidden features that only stereoscopic vision could reveal.

Stereographs are created using a stereo camera, a camera with dual lenses. Stereo cameras remained largely the tools of professional photographers until 1947, when American photographer Seton Rochwite introduced the Stereo Realist. The Stereo Realist featured three lenses: a left lens, a right lens, and a center view-finding lens. This camera enabled amateur photographers to create their own stereographs. More than 130,000 Stereo Realists were sold during its 20 years in production. The hobby of stereophotography peaked in the 1950s, but the Stereo Realist remains popular among collectors and enthusiasts and is still used today.

Although stereographs have lost the popularity they once enjoyed among the general public, they continue to play a role in modern scientific observation. After the Mars Pathfinder spacecraft landed on the surface of Mars in 1997, onboard dual cameras took more than 16,000 stereographic images of the Martian landscape and sent them back to Earth.

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ANAGLYPHS