Information & Communication


Data Compression

Technical Applications

Summary

Current compression technology falls into four categories: data (numerous techniques), audio (ADPCM), image (JPEG), and motion video (MPEG). Virtually any time that information is transmitted, or stored, there is an opportunity to pack it into a more efficient format than the one which was used for presentation or application. The cost of bandwidth, power, memory or storage media, and the competition for them, require that they be treated as a valuable resources.

Characteristics

For example, one key to high definition TV (HDTV) ability to sending twice as many lines of video per image frame and, correspondingly, twice as many pixels per line (four times as many pixels per image), is compression. The United States is finalizing its own unique HDTV standards in order to suppress foreign competition, domestically. However, recent mathematical breakthroughs in wavelet theory, which is more compactly supportable than the JPEG cosine transform, indicate that we can achieve far greater compression ratios, depending on the application. MPEG2 is likely to become the U.S. HDTV standard.

ImpactEconomy

Data compression is essential to harnessing information technology since it enables the enormous data flows involved. It also supports other national goals, such as enabling advances in health care and education technologies and allowing U.S. companies to create communication and video equipment which is competitive in world markets. Data compression has extensive applications for national security and warfighting. The enormous volume of imagery required for our advanced strategic and tactical planning requires that the imagery be appropriately compressed at each transmission. The initial transmissions from the sensor must be lossless, to facilitate photo-interpreter processing and annotating. Conversely, the imagery provided to those carrying out the mission, e.g., gunners, can withstand significant lossy compression without reducing its utility as long as they know what target they are looking at and where that target is located.

WorldView

The United States has a slight lead over Japan and Europe in data compression components and algorithms. The U.S. lead is evident from such original work as a high-definition television digital compression standard that leap-frogged heavily funded foreign efforts to develop analog HDTV systems. The international research community in this area is very tightly connected (especially in academia) so that progress is very quickly shared, resulting in a short time between original result and its use by other organizations. China and Russia generally lag the U.S. by several years, although some outstanding theoretical work has been done in Russia.