Up-to-the-Minute Picture

Minutes after they reached the deck of the Lake Champlain, Astronauts Cooper and Conrad were seen, bearded and smiling, on TV screens across the nation. The images were not live TV pickups, which were not feasible due to technical difficulties. But they were the next best thing: still pictures transmitted almost instantly.

At first the TV screen turned all grey. Then the image took shape, teasingly, as if appearing from behind a slow-parting curtain that moved from left to right. While faint beep-beep-beeps were heard in the background, the picture grew in a series of vertical lines.

In less than a minute, the picture was whole. For the first time on network television, still photographs were transmitted by a process called Videx.

Developed by International Telephone & Telegraph Corp., Videx is essentially an adaptation of the "slow-scan" process used in closed-circuit television and to send television pictures from space.

A videcon tube, much like a standard TV camera tube, "sees" the picture or other photographable object. The tube stores the image in the form of a pattern of varying intensities of light and dark. This pattern is then scanned by an electron beam, which registers the value of the light intensities, from white to grey to black. The electronic signal is next transmitted by radio or ordinary telephone line to a receiving screen.

TV cameramen on the Lake Champlain used Polaroid cameras to snap the pictures that were scanned by Videx. Each picture was scanned for 40 seconds; each frame consisted of 400 vertical lines, compared with the 525 horizontal lines of ordinary TV images. The pictures were transmitted by radio from the ship to Long Island, thence by telephone lines to Houston, where the TV networks were waiting with their receiving equipment. The beeping heard by the TV audience was the sound of the Videx signals.

Unlike regular TV, Videx does not require line-of-sight transmission, and it uses more compact equipment than ordinary TV. Banks are already employing the system to flash check signatures from branches to the main office for verification. The U.S. Weather Bureau sends weather maps and charts by Videx. The military has it too, but keeps the secrecy lid on its use.

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