More about CCTV over IP at the Docklands Light Railway in east London, a finalist in the applications category at the IP in Security Innovation Awards in January 2005.
For passenger and staff safety and to deter vandalism, the Docklands Light Railway (DLR) in London commissioned the installation of digital video recorders on its trains. The systems contract was awarded to Falcon Protec, who, following research and trials, selected Wavelet Technology for the supply of the core digital video recording hardware and software.
The specification for this on-train application required six camera inputs recorded in each carriage, all at real time rates simultaneously with full resolution images, with recordings to be retained for up to 10 days before overwriting. This equates to the capture and digitisation of 150 pictures each and every second across the six cameras. Each unit has to withstand the climatic and mechanical type tests detailed in BS EN 50155, shock and vibration tests detailed in BS EN 61373 and Electro-Magnetic Coupling tests detailed in BS EN 50121-3-2.
Wavelet Technology modified its Sapphire range of Wavestore electronics and LINUX based operating system to meet the criteria. The use of PC104+ industrial grade motherboards was deployed and all the electronics housed in a specially developed 3U high 19-inch rack mountable case; the size of a small briefcase.
The system of 600 cameras will have one DVR fitted on board each carriage. All six cameras will be powered from the unit, which also incorporate 2.4GHz wireless transceivers in order to maintain full network capabilities across the 27km Wide Area Network (WAN) during full operation of the trains. Remotely located security staff can select and view any four cameras at once across the network in real time (25 images per second).
Wavelet Technology’s proprietary encryption techniques and use of incorruptible Wavelet compression allows evidence to be admissible and presented in a court of law to aid prosecution, the makers say.
Control centre
The command and control centre uses IP (Internet Protocol) to allow an operator to log on via a PC to any DVR and monitor or download the required images. The system transmits real time video imagery from any of the 600 cameras from any train operating in the rail network to the central monitoring station. This provides the monitoring staff with the ability to respond to alarm activations and recorded incidents. Alarm-triggered and time-lapse recordings can be searched and retrieved. The recorders feature a pre-event recording feature that enables video images prior to an incident to be retained at real time rates.
Video interface
Wavestoreโs Extended Video Interface (EVI) is software that permits CCTV installers or transport operator to design and create multiple windows for the interface and control of the systemโs cameras in either PAL or NTSC, on any of the common PC platforms; (Windows, LINUX or Apple Mac). The programme writer has control, the makers say, over the geometry and positioning of each viewing window to display any camera in any window, for both live and archived video, together with multiple synchronised audio channels. Different display options address varying security requirements, such as football matches or exhibitions.
IP networking
IP provides system status and control. The transmission system design guarantees, the makers say, a data rate of 8Mbps using a variant of 802.11b implemented with OFDM modulation to reduce urban multi-path fading effects.
