Presence detection device and method

Patent metadata

Field	Value
Publication number	US-11462086-B2
Application number	US-202117207073-A
Country	US
Kind code	B2
Filing date	Mar 19, 2021
Priority date	Apr 15, 2020
Publication date	Oct 4, 2022
Grant date	Oct 4, 2022

Abstract

In accordance with an embodiment, a detection device includes: an infrared temperature sensor configured to provide a temperature signal associated with an heat emission of at least one individual within a monitored area; an electrostatic-charge-variation sensor configured to provide a charge-variation signal indicative of a variation of electrostatic charge associated with the at least one individual; and a processing unit, coupled to the infrared temperature sensor and to the electrostatic-charge-variation sensor, the processing unit configured to detect a presence of the at least one individual within the monitored area by receiving the temperature signal and the charge-variation signal, and jointly processing the temperature signal and charge.

First claim

What is claimed is:

1. A detection device, comprising:
an infrared temperature sensor configured to provide a temperature signal associated with an heat emission of at least one individual within a monitored area;
an electrostatic-charge-variation sensor configured to provide a charge-variation signal indicative of a variation of electrostatic charge associated with the at least one individual; and
a processing unit, coupled to the infrared temperature sensor and to the electrostatic-charge-variation sensor, the processing unit configured to detect a presence of the at least one individual within the monitored area by receiving the temperature signal and the charge-variation signal, and jointly processing the temperature signal and charge-variation signal.

2. The detection device according to claim 1 , wherein the processing unit is further configured to:
process a temperature gradient associated with a variation of the temperature signal with respect to a baseline value in order to detect a first presence indication;
process a variation over time of the charge-variation signal in order to detect a second presence indication; and
generate a presence signal indicative of the presence of the at least one individual within the monitored area when both the first presence indication and the second presence indication indicate the presence of the at least one individual in a same time interval.

3. The detection device according to claim 2 , wherein:
the first presence indication indicates the presence of the at least one individual when the temperature gradient exceeds, in absolute value, a temperature threshold; and
the second presence indication indicates the presence of the at least one individual when features of the charge-variation signal is associated with at least one step made by the at least one individual.

4. The detection device according to claim 3 , wherein the processing unit is configured to determine whether the features of the charge-variation signal is associated with at least one step made by the at least one individual by:
determining whether amplitude peaks of the charge-variation signal exceed a fixed or adaptive charge threshold; or
analyzing specific patterns of the charge-variation signal, and determining whether the analyzed specific patterns of the charge-variation signal are indicative of the presence of the at least one individual.

5. The detection device according to claim 2 , wherein the processing unit is configured to enable updating of the baseline value of the temperature signal for automatically adapting the detection to conditions of ambient temperature of the monitored area, conditionally with respect to the processing of the charge-variation signal.

6. The detection device according to claim 5 , wherein the processing unit is configured to enable updating of the baseline value of the temperature signal, only in a case where processing of the charge-variation signal over time is indicative of an absence of individuals in the monitored area.

7. The detection device according to claim 5 , wherein the processing unit is configured to enable updating of the baseline value of the temperature signal when the charge-variation signal varies within a charge threshold.

8. The detection device according to claim 1 , wherein the electrostatic-charge-variation sensor comprises:
at least one electrode configured to be arranged facing the monitored area;
a high-impedance instrumentation amplifier having an input coupled to the electrode; and
an analog-to-digital converter coupled at an output of the instrumentation amplifier for providing the charge-variation signal.

9. The detection device according to claim 1 , wherein the processing unit, the infrared temperature sensor, and the electrostatic-charge-variation sensor are integrated within a same package having electrical-connection elements towards an outside of the package.

10. An electronic apparatus comprising:
the detection device according to claim 1 ; and
a main controller coupled to the processing unit of the detection device, the main controller configured to receive a presence signal indicative of the presence of the at least one individual within the monitored area from the processing unit of the detection device.

11. The electronic apparatus according to claim 10 , wherein the main controller is configured to activate an anti-intrusion alarm based on the presence signal.

12. A method for detecting a presence of at least one individual within a monitored area, comprising:
providing, by an infrared temperature sensor, a temperature signal associated with a heat emission of at least one individual within the monitored area;
providing, by an electrostatic-charge-variation sensor, a charge-variation signal indicative of a variation of electrostatic charge associated with the at least one individual; and
jointly processing the temperature signal and the charge-variation signal to detect a presence of the at least one individual within the monitored area.

13. The method according to claim 12 , wherein joint processing comprises:
processing a temperature gradient associated with a variation of the temperature signal with respect to a baseline value for detecting a first presence indication;
processing a variation of the charge-variation signal over time for detecting a second presence indication; and
generating a presence signal indicative of the presence of the at least one individual within the monitored area when the first presence indication and the second presence indication are jointly detected in a same time interval.

14. The method according to claim 13 , further comprising enabling updating of the baseline value of the temperature signal for automatic adaptation of the detection to conditions of ambient temperature of the monitored area, conditionally with respect to processing of the charge-variation signal.

15. The method according to claim 14 , further comprising enabling updating of the baseline value of the temperature signal only when the processing of the variation of the charge-variation signal indicates an absence of individuals in the monitored area.

16. The method according to claim 14 , further comprising:
determining whether the charge-variation signal varies within a charge threshold;
and enabling updating of the baseline value of the temperature signal when the charge-variation signal varies within the charge threshold.

17. The method according to claim 16 , wherein the charge threshold is based on a mean and a deviation of the of the charge-variation signal.

18. A presence detection system comprising:
an infrared sensor;
an electrostatic-charge-variation sensor; and
a processor configured to:
extract features from a charge-variation signal provided by the electrostatic-charge-variation sensor,
determine whether the extracted features match features associated with a human presence,
determine a temperature difference of a temperature signal provided by the infrared sensor,
determine whether the temperature difference is outside of a first temperature range, and
generate a presence detection signal when the extracted features match features associated with the human presence and the temperature difference is outside of the first temperature range within a same time interval.

19. The presence detection system of claim 18 , wherein the processor is further configured to:
determine whether the charge-variation signal provided by the electrostatic-charge-variation sensor varies within a first charge va

Assignees

• St Microelectronics Srl

Inventors

• Alessi Enrico Rosario
• Passaniti Fabio

Classifications

• G01V9/005

  by thermal methods, e.g. after generation of heat by chemical reactions · CPC title

• G08B13/26

  by proximity of an intruder causing variation in capacitance or inductance of a circuit · CPC title

• G08B13/2494 Primary

  by interference with electro-magnetic field distribution combined with other electrical sensor means, e.g. microwave detectors combined with other sensor means · CPC title

• G08B13/22

  Electrical actuation · CPC title

• G08B29/26

  by updating and storing reference thresholds · CPC title