The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 24, 2012
Filed:
May. 19, 2006
Michael E Nilsson, Ipswich, GB;
Rory S Turnbull, Ipswich, GB;
Roberto Alvarez Arevalo, Ipswich, GB;
British Telecommunications public limited company, London, GB;
Abstract
Faults resulting in reception of a still, but unknown, frame are recognized by comparing each received frame of the video signal with its predecessor, incrementing a counter in the event that the difference between the frames falls below a threshold; and generating an alarm signal in the event that the count of the counter exceeds a predetermined count. Other types of fault such as loss of signal (i.e. reception of just noise) are recognized by incrementing the counter whenever the difference exceeds a threshold. Similar results may be obtained by instead the monitoring quantization step size and/or number of transmitted bits of a digitally coded signal, and noting that it falls below, or exceeds, a threshold. A preferred option is to compute a complexity measure, being a monotonically increasing function (e.g the product) of the quantization step size and of the number of coded bits and compare this with the threshold value. Faults occasioned by receipt of a particular fixed image instead of the wanted picture are recognized by comparing each frame of the video signal with the fixed image, and generating an alarm signal in the event that the difference between the frames consistently falls below a threshold.