TECHNOLOGY PLATFORMS FOR TELEVISION SECURITY ABOARD BUSES
W S Edwards · 1997
The availability of improved video coding/decoding (CODEC) algorithms and standards along with new bandwidth efficiency requirements mandated by a Federal Communications Commission (FCC) establish an environment where the transmission of images from video camera(s) located on a bus can significantly improve security for bus drivers and passengers. Available technologies also improve the effectiveness of security's special operations when responding to hostage situations or for immediate identification of perpetrators. Standards are available and/or emerging in the video codec market that provide improved clarity and motion compensation of video transmitted at lower bandwidths. The International Consultative Committee for Telephone and Telegraph/International Telecommunications Union (CCITT/ITU) H.320 suite of Standards is currently used for much of the world's video teleconferencing operating between 56Kbps and 1.544Mbps. The more recently adopted H.324 standard lowers even further the bandwidth requirements for digital video and audio transmission, permitting reasonable quality video using existing voice grade telephone facilities. Work is underway on two newer compression techniques, wavelet and fractal, permitting an even higher level of compression and improved video quality. The FCC's adoption of standards requiring a data transmission rate of 4800 bits per second (bps) over a 6.25 KHz radio channel, or 19.2kbps over a 25 KHz radio channel, makes available a digital bandwidth using wireless links suitable for transmitting quality video usable to identify individuals and/or see events happening real-time when used with newer compression algorithms. While the continuous transmission of video from buses would be an inefficient use of scarce radio frequency (RF) spectrum, the use of the bandwidth to respond to emergency situations may be justified. Through the integration of video systems with RF systems used for other intelligent transportation system components, a powerful tool for security personnel is now possible.