DEVICE, SYSTEM, AND METHOD FOR DETECTING HUMAN PRESENCE

• US 20180157376A1
• Filed: 12/02/2016
• Published: 06/07/2018
• Est. Priority Date: 12/02/2016
• Status: Active Grant

• Current Assignee: STMicroelectronics SAS (STMicroelectronics NV)
• Original Assignee: STMicroelectronics SAS (STMicroelectronics NV)
• Inventors: Lemarchand, Olivier
• Granted Patent: US 10,557,965 B2
• Time in Patent Office: Days
• CPC Class Codes: G01S 17/04 Systems determining the presence of a target
• CPC Class Codes: G01S 17/10 using transmission of interrupted, pulse-modulated waves determination of distance by phase measurements G01S17/32
• CPC Class Codes: G01S 17/58 Velocity or trajectory determination systems; Sense-of-movement determination systems
• CPC Class Codes: G01S 7/484 Transmitters
• CPC Class Codes: G01V 8/12 using one transmitter and one receiver
• CPC Class Codes: G06F 1/3231 Monitoring the presence, absence or movement of users
• CPC Class Codes: G06F 3/017 Gesture based interaction, e.g. based on a set of recognized hand gestures interaction based on gestures traced on a digitiser G06F3/04883
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

An embodiment device includes an optical source configured to transmit an optical pulse and an optical sensor configured to receive a reflection of the optical pulse. The device further includes a processor configured to determine a parameter based on the reflection, the parameter indicative of a distance between the device and a target; and a controller configured to generate a first control signal based on the parameter, the first control signal being configured to control an operation of the optical source.

Claims

1. A device, comprising:

an optical source configured to transmit an optical pulse;

an optical sensor configured to receive a reflection of the optical pulse;

a processor configured to determine a parameter based on the reflection, the parameter indicative of a distance between the device and a target; and

a controller configured to generate a first control signal based on the parameter, the first control signal being configured to control an operation of the optical source.

2. The device of claim 1, wherein the optical source comprises at least one of a vertical-cavity surface-emitting laser, a quantum well laser, a quantum cascade laser, an interband cascade laser, or a vertical external-cavity surface-emitting laser.

3. The device of claim 1, wherein the optical sensor comprises a sensing array comprising a plurality of optical elements.

4. The device of claim 3, wherein the plurality of optical elements comprises at least one of a photo diode, an avalanche photo diode, or a single-photon avalanche diode.

5. The device of claim 1, wherein the controller is further configured to generate a second control signal based on the parameter, the second control signal being configured to control an operation of an electronic device communicatively coupled to the controller.

6. The device of claim 1, wherein the optical source is configured to transmit the optical pulse for a first time duration, there being a second time duration between consecutive transmissions of the optical pulse.

7. The device of claim 6, wherein the first control signal is configured to control the operation of the optical source by varying at least one of the first time duration or the second time duration.

8. A method, comprising:

transmitting, using an optical source, a plurality of optical pulses;

receiving, using an optical sensor, a plurality of reflections, each reflection being a reflection of a corresponding optical pulse off a target;

determining, using a processor, a parameter based on the plurality of reflections, the parameter indicative of a distance between the optical source and the target; and

controlling an operation of the optical source based on a comparison of the parameter against a plurality of thresholds.

9. The method of claim 8, wherein determining the parameter based on the plurality of reflections comprises:

determining, for each reflection of the plurality of reflections, a time elapsed between the transmitting of the optical pulse and the receiving of the reflection; and

determining the parameter based on the time elapsed.

10. The method of claim 9, wherein determining the parameter based on the time elapsed comprises:

determining a plurality of distance estimates based on the time elapsed for each reflection of the plurality of reflections; and

determining a ratio of a mean of the plurality of distance estimates to a standard deviation of the plurality of distance estimates.

11. The method of claim 8, wherein the optical source is configured to transmit the optical pulse for a first time duration at a ranging frequency, the ranging frequency indicative of a second time duration between consecutive ones of the plurality of optical pulses.

12. The method of claim 11, wherein controlling the operation of the optical source comprises setting, in response to the parameter being greater than a first parametric threshold, the ranging frequency to be in a first frequency range and the first time duration to be in a second time range.

13. The method of claim 12, wherein the ranging frequency is about 50 Hz and the first time duration is about 20 milliseconds.

14. The method of claim 11, wherein controlling the operation of the optical source comprises setting, in response to the parameter being less than a first parametric threshold for a period of time longer than a first temporal threshold, the ranging frequency to be in a second frequency range and the first time duration to be in a first time range.

15. The method of claim 14, wherein the ranging frequency is about 1 Hz and the first time duration is about 1 second.

16. The method of claim 14, wherein controlling the operation of the optical source comprises, in response to the parameter being less than a second parametric threshold, the ranging frequency to be in the second frequency range and the first time duration to be in a second time range.

17. The method of claim 16, wherein the ranging frequency is about 1 Hz and the first time duration is about 20 milliseconds.

18. The method of claim 16, wherein the second parametric threshold is less than the first parametric threshold.

19. A system, comprising:

a presence detector, comprising;

an optical source configured to transmit an optical pulse;

an optical sensor configured to receive a reflection of the optical pulse;

a processor configured to determine a parameter based on the reflection, the parameter indicative of a distance between the presence detector and a target; and

a controller configured to generate a first control signal based on the parameter, the first control signal being configured to control an operation of the optical source; and

an electronic device coupled to the presence detector.

20. The system of claim 19, wherein the controller is further configured to generate a second control signal based on the parameter, the second control signal being configured to control an operation of the electronic device.

21. The system of claim 20, wherein the second control signal being configured to cause the electronic device to switch between a low-power state and an active state.

22. The system of claim 20, wherein the optical source is configured to transmit the optical pulse for a first time duration and at a ranging frequency, the ranging frequency being indicative of a second time duration between consecutive transmissions of the optical pulse.

23. The system of claim 22, wherein the first control signal is configured to control the operation of the optical source by varying at least one of the first time duration or the ranging frequency.

24. A system, comprising:

a presence detector configured to detect an infant within a detection area, the presence detector comprising;

an optical source configured to transmit an optical pulse;

an optical sensor configured to receive a reflection of the optical pulse;

a processor configured to determine a parameter based on the reflection, the parameter indicative of a distance between the presence detector and the infant; and

an electronic device coupled to the presence detector.

25. The system of claim 24, wherein the presence detector further comprises a controller configured to generate a first control signal based on the parameter, the first control signal being configured to control an operation of the optical source.

26. The system of claim 25, wherein the controller is further configured to generate a second control signal based on the parameter, the second control signal being configured to control an operation of the electronic device.

27. The system of claim 26, wherein the operation of the electronic device comprises sounding an alarm in response to the parameter being less than a parametric threshold for longer than a predetermined temporal threshold.