Video image transmission system via standard telephone lines and radio channels.
Defense & Security Electronics.- 1995 .-27, №9.-P. 19
Video image transmission system via standard telephone lines and radio channels.
Company Racal Radio (UK) has announced a new technology developed by its specialists that enables the transmission of video images over standard telephone channels, cellular radio telephones and narrowband radio channels with a fixed operating frequency or with pseudo-random reorganization (frequency hopping). The RAICATS (Racal Image Compression and Transmission System) system based on this technology is compatible with standard telephone channels and other radio stations of the Racal companywithout their modification.
The limited bandwidth of the telephone and radio channels requires a high degree of compression of the video signal bandwidth. Known data compression methods, such as the JPEG still image compression algorithm and MPEG multipulse control coding, turned out to be ineffective and required increased protection against errors and interference typical of radio channels. Therefore, more effective image compression methods were used, such as the modified fast lapped transform (MFLT) and Error Resilient Entropy Coding (EREC), which allow some deterioration of images, but ensure rapid restoration of their quality in the event of data loss,
Potential users of the RAICATS systemThe armed forces, police, and civil security agencies will be the target groups. In the armed forces, the ability to transmit video images via radio can be used to support reconnaissance and surveillance teams, obtain video information about the actual military situation, and to protect borders and ensure the security of individual areas. Police and law enforcement agencies can use the system to transmit images from crime scenes, photographs of suspects, fingerprints, and images of the situation at the scene of incidents.
The RAICATS system uses a miniature low-line television camera at the transmitting end and a standard computer with an image decompression device and control software at the receiving end.
The company currently offers three versions of the RAICATS system. The first of these, the MA4808C, is a pocket-sized book-sized model that can be connected to a telephone and mobile radiotelephones. The second version is the MA4808C. MA4808A is designed for connection with radio stations, and the third — MA4704 is focused on military applications.