Abstract: A video background processing system is disclosed that is configured to receive a video stream including a plurality of successive first video frames at a first resolution. The system comprises a video resolution modifier configured to reduce the resolution of the first video frames from the first resolution to a second resolution lower than the first resolution and thereby generate second video frames. The system also comprises a foreground determiner configured to determine a foreground portion and a background portion in the second video frames and to produce first foreground data indicative of locations of the foreground and background portions in the second video frames at the second resolution, wherein the foreground determiner is configured to use the first foreground data to generate second foreground data indicative of locations of the foreground and background portions in the first video frames.

Abstract: An apparatus and method for monitoring of optical signals 60 at a node (12, 14, 16) in a WDM telecommunications system 10 comprising the employment of photodiodes (54, 56, 58). Each of the photodiodes (54, 56, 58) has a short response time relative to a number of bit periods of the optical signal to permit measurement of the optical power thereof. Such a photodiode (54, 56, 58) can be used to monitor many nodes (12, 14, 16) within the system 10 and facilitates monitoring of optical signals in nodes which are far apart. The photodiode (54, 56, 58) also permits the Optical Signal to Noise Ratio (OSNR) of the optical signal 60 to be calculated by obtaining values for a maximum optical power P1 and a minimum optical power P0 for a particular optical signal 60.

Abstract: A component for an optical communication network comprises a source (6) for an optical communication signal, an output port (11) for outputting the optical communication signal on an optical transmitting fiber (1), a light sensor (14; 15) and an optical circulator (9) for transmitting the optical communication signal from the source (6) to the output port (11) and for transmitting light reflected or received from outside at the output port (11) to the light sensor (14; 15). The light sensor (14, 15) has an evaluation circuit (13) connected to it for detecting a time delay between a time marker of a light signal from the source and the corresponding time marker of the light arriving at the light sensor (14; 15).

Abstract: An optical network comprises a transmitter node (1), a receiver node (4) and an optical fibre (3) for transmitting an optical wavelength-division multiplex signal having payload channels and a supervisory channel between the nodes (1, 4). At least one of the nodes has an amplifier (8, 13) which is passed by the multiplex signal. The transmitter node (1) has a source (11) for the supervisory channel and a multiplexer (12) for combining the payload channels and the supervisory channel in order to form the optical wavelength-division multiplex signal, and the receiver node (4) has a sink (16) for the supervisory channel and a demultiplexer (14) for separating the wavelengthdivision multiplex signal into supervisory and the payload channels.

Abstract: In a wavelength-selective optical signal processing device, an outcoupling filter for decomposing an incoming wavelength multiplex comprising a plurality of channels at different wavelengths into a first and a second group of channels and an incoupling filter for combining the first group after having passed through a processing unit and the second group into an outgoing wavelength multiplex are combined in a continuous wavelength-selective reflecting structure.

Abstract: An L-band EDFA may have three amplifier stages. In the first stage, a high power 980 nm laser is used to generate C-band ASE noise which is used to pump the erbium doped fiber of the second stage. The second stage fiber is arranged as a plug-in module which connects between a first stage isolator and a mid-stage loss between the second and third stages. The desired gain of the amplifier is obtained by selecting a plug-in module with a length of fiber that will give the desired amplifier output power for a given input power.

Abstract: A system for controlling gain of an optical amplifier that is disposed in a WDM optical communication network for amplifying an input WDM signal to produce a corresponding amplified output WDM signal is operative for measuring average optical powers of the input WDM signal over first and second wavebands, each covering a wavelength range that includes at least one wavelength channel of the WDM network and is operative for measuring the average optical powers of the amplified output WDM signal over the first and second wavebands. The system further determines gain values over the first and second wavebands from the average input and output powers and adjusts a variable of the optical amplifier to ensure that the difference between the gain values is maintained to within a predetermined value thereby ensuring a substantially flat gain slope profile.