The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Premises Technologies Premises Technologies The Arrival of Compression To deal with the storage and transmission issues associated with image-based applications, corollary technologies such as digital com- pression have emerged. The main technique used today for still image compression is JPEG, developed by the Joint Photographic Experts Group, a cooperative effort between the International Organization for Standardization (ISO), ITU-T, and the International Electrotechnical Commission (IEC). JPEG, discussed briefly in an earlier chapter, works as follows. Digital images, composed of thousands of picture elements (pixels), are "dis- solved" into a mosaic of 16-pixel-by-16-pixel blocks. These blocks are then reduced to eight-by-eight blocks by removing every other pixel value. JPEG software then calculates an average brightness and color value for each block, which is stored and used to reconstruct the original image during decompression. Today, still-image technologies remain in widespread use, and will continue to play a key role in the application of visual technologies. But others have emerged as well. One of the most promising is video. Video The video story begins in 1951 at RCA's David Sarnoff Research Insti- tute. During a celebration dinner, Brigadier General David Sarnoff, chairman of RCA and the founder of NBC, requested that the institute work on three new inventions, one of them what he called a "videograph." In his mind, a videograph was a device capable of capturing television signals on some form of inexpensive medium, such as tape. Remember the time frame that we're talking about. Thanks to Philo T. Farnsworth, who invented the predecessor of today's cathode ray tube (CRT-and yes, that's his real name), electronic television became a real- ity in the 1920s. By the early 1950s, black and white television was wide- spread in America. The gap between the arrival of television and the demand