Detection Apparatus

• US 20110169629A1
• Filed: 02/02/2006
• Published: 07/14/2011
• Est. Priority Date: 02/02/2005
• Status: Active Grant

• Current Assignee: Pyronix Ltd. (Hangzhou Hikvision Digital Technology Company Limited)
• Original Assignee: Pyronix Ltd. (Hangzhou Hikvision Digital Technology Company Limited)
• Inventors: Cooper, Glyn
• Granted Patent: US 8,164,437 B2
• Time in Patent Office: Days
• US Class Current: 340/507
• CPC Class Codes: G01S 13/56 for presence detection presence detection using near field arrangements G01V3/00, e.g. G01V3/08, G01V3/12; burglar, theft or intruder alarms with electrical actuation G08B13/22 - G08B13/26
• CPC Class Codes: G08B 13/2494 by interference with electro-magnetic field distribution combined with other electrical sensor means, e.g. microwave detectors combined with other sensor means
• CPC Class Codes: G08B 29/046 prevention of tampering with detection circuits
• CPC Class Codes: G08B 29/183 Single detectors using dual technologies G08B13/1672, G08B13/2448, G08B13/2494 take precedence

Abstract

Embodiments of the present invention relate to a range reduction detection apparatus that is able to detect blocking of its field of view. Detection of an event, due to movement or intrusion within the field of view, is arranged to start a timer, which will time-out thereby providing an indication of such blocking unless a subsequent event is detected within the time-period.

Claims

1. A range reduction or blocking detection apparatus for detecting comprising means, responsive to at least a first input signal, to generate a range reduction or blocking detection alarm signal, providing an indication that the field of view of the detector has been reduced or obscured by an object within the field of view relative to a specified performance characteristic, after a first period of time, measured relative to the first input signal, unless a second input signal is received within that first period of time.

2. An apparatus as claimed in claim 1 in which the means to generate the alarm signal comprises a timer arranged to time out after the first period of time and to generate, or cause to be generated, the range reduction detection alarm signal and means to detect input of the second input signal to at least stop or reset the timer.

3. An apparatus as claimed in claim 1 further comprising at least one of a microwave sensor and a passive infrared sensor for generating at least one of the first and second input signals.

4. An apparatus as claimed in claim 1 further comprising an alarm to generate an alarm output in response to the range reduction or blocking detection signal.

5. An intrusion monitoring apparatus comprising at a detector arranged to generate at least a first signal indicating detection of the presence of an object within an associated field of view;

the apparatus comprising a range reduction or blocking detection as claimed in claim 1 for processing the first signal and determining whether or not the detector generates a second signal within a predetermined period of time of the first signal and generate a reduction range or blocking detection signal indicative of an object having been placed within the associated field of view thereby obscuring part of that field of view.

10. A program comprising code for implementing an apparatus as claimed in claim 1.

11. Machine-readable storage storing a program as claimed in claim 10.

6. An intrusion detection apparatus that is able to detect blocking of its field of view by an object placed within that field of view;

the apparatus comprising means, responsive to detecting an event, due to movement or intrusion within the field of view, to start a timer, which will time-out after a predetermined time period thereby providing an indication of such blocking unless a subsequent event is detected within the predetermined time period.

7. (canceled)

8. An anti-blocking method;

comprising the steps of detecting an event within a protected volume of an intrusion monitoring arrangement;

starting a timer in response to said detecting and generating an alarm signal within a predetermined period of time of starting the timer unless a subsequent event is detected within the protected volume.

12. A program comprising code for implementing a method as claimed in claim 8.

9. (canceled)