Process for monitoring the openings to an enclosed space

• US 5,506,567 A
• Filed: 09/26/1994
• Issued: 04/09/1996
• Est. Priority Date: 10/07/1993
• Status: Expired due to Fees

• Current Assignee: Temic Telefunken Microelectronic GmbH (Continental AG)
• Original Assignee: Temic Telefunken Microelectronic GmbH (Continental AG)
• Inventors: Fach, Hans-Joachim, Ertel, Rainer, Bichlmaier, Gunther, Grafje, Dieter, Doefler, Reiner, Teubert, Udo, Dilz, Bernhard, Friedrich, Ferdinand, Rupprecht, Thomas, Hettich, Gerhard, Wiedemann, Werner, Robitschko, Peter
• Primary Examiner(s): Swarthout, Brent A.
• Assistant Examiner(s): WONG, ALBERT KANG
• Application Number:
  US08/313,853
• Time in Patent Office: 561 Days
• Field of Search: 340/555, 340/565, 340/545, 340/550, 340/552, 340/600
• US Class Current: 340/555
• CPC Class Codes: B60R 25/1004 Alarm systems characterised by the type of sensor, e.g. current sensing means using door lock sensors B60R25/1001
• CPC Class Codes: E05F 15/431 specially adapted for vehicle windows or roofs
• CPC Class Codes: E05Y 2400/452 for saving energy
• CPC Class Codes: E05Y 2400/61 Power supply
• CPC Class Codes: E05Y 2900/55 Windows
• CPC Class Codes: G01S 17/04 Systems determining the presence of a target
• CPC Class Codes: G01S 17/88 Lidar systems specially adapted for specific applications
• CPC Class Codes: G01S 7/4813 Housing arrangements
• CPC Class Codes: G08B 13/2491 Intrusion detection systems, i.e. where the body of an intruder causes the interference with the electromagnetic field

Abstract

A process for monitoring an opening of an enclosed space by an IR alarm system, wherein: a measuring process is generated whereby a modulated IR beam is emitted by at least one IR emitting element of an optoelectronic unit in the form of a pulse and the beam reflected from marginal areas of the opening is detected as a measurement signal by at least one IR receiving element of the optoelectronic unit, with the directional characteristic of th IR beam being matched, by optical components in the path of the beam, to the opening being monitored; the measurement signal detected by the receiving element is compared with a mean value of the previous measurement signals, and a normal operating mode of the alarm system is initiated if there is an approximate correlation between the measurement signal and the mean value, or an alarm operating mode of the alarm system is initiated if there is a significant deviation between the measurement signal and the mean value; in the normal operating mode, the next measuring process is generated after a pause in time, during which the control unit, emitting element and receiving element are switched off; and, in the alarm operating mode, a number of measuring processes are generated in immediate succession and compared with criteria stored in the control module, and an alarm signal is tripped if the measurement signals from the measuring processes correspond with the stored criteria.

Claims

1. A process for monitoring an opening to an enclosed space by an IR alarm system, comprising the steps of:

providing a control module having a control unit with at least an IR emitting element for emitting an IR beam and at least one IR receiving element for detecting a reflected beam, and an optical unit including optical components disposed in the beam path for matching a directional characteristic of an IR beam emitted by the IR emitting elements and detected by the receiving element to the opening to be monitored;

generating a measuring process in which a modulated IR beam from at least one IR emitting element of the optoelectronic unit is emitted in the form of a pulse and the beam reflected at marginal areas of the opening is detected as a measurement signal by the at least one IR receiving element of the optoelectronic unit;

comparing the measurement signal, with ambient light content eliminated, detected by the receiving element with a mean value of previously detected measuring signals;

depending on the comparison, initiating a normal operating mode of the alarm system if there is a correlation between the measurement signal and the mean value, and initiating an alarm operating mode of the alarm system if there is no correlation;

in the normal operating mode, generating the next measuring process after a pause in time and switching off the control unit, the emitting elements and the receiving element during this pause in time; and

,

in the alarm operating mode, generating a number of measuring processes in immediate succession, comparing the detected measurement signals with criteria which are stored in the control module and which identify the penetration of objects or persons through the monitored opening, and triggering an alarm signal if the measurement signals of the measuring process correspond with the stored criteria.

2. A process according to claim 1, wherein said step of providing includes mounting the optical components of the optical unit in a fixed position relative to the emitting elements and receiving element of the optoelectronic unit.

3. A process according to claim 1, further comprising providing timing signals from a timing element to define the pauses in time during the normal operating mode.

4. A process according to claim 1, further comprising adjusting a measuring range for the measurement signal during an adaptation phase such that the measurement signal in the normal operating mode lies in the middle of a measurement range.

5. A process according to claim 4, further comprising initiating a said adaptation phase after every initial activation of the alarm system, after every case of triggering of an alarm, and after a reference value corresponding to the measurement signal in the normal operating range, has drifted out of a variable limit window.

6. A process according to claim 1, further comprising measuring the ambient light to provide a ambient light signal, and using the ambient light signal to convert the measurement signal to a value without the ambient light content, thereby eliminating the ambient light dependency of the IR receiving element.