Device, system, and method for detecting human presence

• US 10,557,965 B2
• Filed: 12/02/2016
• Issued: 02/11/2020
• Est. Priority Date: 12/02/2016
• Status: Active Grant

• Current Assignee: STMicroelectronics SAS (STMicroelectronics NV)
• Original Assignee: STMicroelectronics SAS (STMicroelectronics NV)
• Inventors: Lemarchand, Olivier
• Primary Examiner(s): Patel, Nitin
• Assistant Examiner(s): Onyekaba, Amy
• Application Number:
  US15/367,780
• Publication Number:
  US 20180157376A1
• Time in Patent Office: 1,166 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 in accordance with a timing budget and a ranging period, the timing budget corresponding to a duration in time during which a distance is measured, by the device, from the device to a target, the ranging period corresponding to a period of time between consecutive distance measurements by the device;

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

a processor configured to determine a parameter corresponding to a quantitative change in the distance between the device and the target, the quantitative change corresponding to distances measured by the device based on the reflection of the optical pulse over consecutive distance measurements by the device; and

a controller configured to generate a first control signal based on the parameter, the first control signal being configured to set the timing budget and the ranging period for a subsequent transmission of the optical pulse by 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 operation of an electronic device communicatively coupled to the controller.

6. The device of claim 1, wherein the quantitative change corresponds to a macro-variation in a movement of the target, a micro-variation in the movement of the target, a detection of a gesture performed by the target, or a combination thereof.

7. The device of claim 1, wherein the processor is further configured to determine an absence of a micro-variation in a movement of the target based on the quantitative change, and based thereon, generate a second control signal to switch a second device from an active state to a low-power state, the second device communicatively coupled to the device.

8. The device of claim 1, wherein the processor is further configured to determine a micro-variation in a movement of the target based on the quantitative change, and based thereon, generate a second control signal to retain a second device in an active state, the second device communicatively coupled to the device.

9. The device of claim 8, wherein the target is an animate object, the micro-variation in the movement of the animate object corresponding to respiration or variations in posture or position of the animate object.

10. The device of claim 1, wherein determining the parameter based on the reflection of the optical pulse comprises:

determining a time elapsed between transmitting the optical pulse and receiving the reflection of the optical pulse; and

determining the parameter based on the time elapsed.

11. The device of claim 1, wherein in a first mode of the device the processor is configured to determine that the parameter is less than a first parametric threshold, and based thereon, determine a consecutive time duration during which the parameter is less than the first parametric threshold.

12. The device of claim 11, wherein in the first mode of the device is configured for high-speed ranging, the first mode corresponding to a timing budget from about 16 milliseconds (ms) to about 100 ms and a ranging period from about 10 Hertz (Hz) to about 120 Hz.

13. The device of claim 11, wherein in the first mode the processor is further configured to determine that the consecutive time duration during which the parameter is less than the first parametric threshold exceeds a first temporal threshold, and based thereon, switch from the first mode to a second mode of the device.

14. The device of claim 13, wherein in the second mode of the device the processor is configured to determine that the parameter is less than a second parametric threshold, and based thereon, determine a consecutive time during which the parameter is less than the second parametric threshold.

15. The device of claim 14, wherein in the second mode the device is configured for high-accuracy ranging, the second mode corresponding to a timing budget from about 0.5 seconds to about 2 seconds and a ranging period from about 0.5 Hertz (Hz) to about 10 Hz.

16. The device of claim 14, wherein in the second mode the processor is further configured to determine that the consecutive time duration during which the parameter is less than the second parametric threshold exceeds a second temporal threshold, and based thereon:

switch from the second mode to a third mode of the device; and

generate a second control signal to switch a second device from an active state to a low-power state, the second device communicatively coupled to the device.

17. The device of claim 16, wherein the first temporal threshold is from about 3 seconds to about 8 seconds and the second temporal threshold is from about 10 seconds to about 25 seconds.

18. The device of claim 16, wherein in the third mode the device is configured for low-power ranging, the third mode corresponding to a timing budget from about 16 milliseconds (ms) to about 100 ms and a ranging period from about 0.5 Hertz (Hz) to about 10 Hz.

19. The device of claim 16, wherein in the third mode the processor is further configured to determine a macro-variation in a distance from the device to the target, and based thereon, generate a third control signal to switch the second device from the low-power state to the active state.

20. The device of claim 14, wherein in the second mode the processor is further configured to determine that the consecutive time duration during which the parameter is less than the second parametric threshold exceeds a second temporal threshold, and based thereon:

activate a third mode of operation of the device; and

generate an audible alarm by the device to alert inactivity.

21. A system, comprising:

a presence detector, comprising;

an optical source configured to transmit an optical pulse in accordance with a timing budget and a ranging period, the timing budget corresponding to a duration in time during which a distance is measured from a device to a target, the ranging period corresponding to a period of time between consecutive distance measurements by the device;

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

a processor configured to determine a parameter corresponding to a quantitative change in the distance between the device and the target, the quantitative change corresponding to distances measured by the device based on the reflection of the optical pulse over consecutive distance measurements by the device; and

a controller configured to generate a first control signal based on the parameter, the first control signal being configured to set the timing budget and the ranging period for a subsequent transmission of the optical pulse by the optical source; and

an electronic device coupled to the presence detector.

22. The system of claim 21, 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.

23. The system of claim 22, wherein the second control signal being configured to cause the electronic device to switch between a low-power state and an active state.

24. The system of claim 22, 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.

25. The system of claim 24, 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.

26. A device, comprising:

a laser configured to transmit an optical pulse in accordance with a timing budget and a ranging period, the timing budget corresponding to a duration in time during which a distance is measured, by the device, from the device to a target, the ranging period corresponding to a period of time between consecutive distance measurements by the device;

a sensing array configured to receive a reflection of the optical pulse, wherein the sensing array comprises a plurality of optical elements, each optical element of the plurality of optical elements comprising an element selected from a group consisting of a photo diode, an avalanche photo diode, and a single-photon avalanche diode;

a processor configured to determine a parameter corresponding to a quantitative change in the distance between the device and the target, the quantitative change corresponding to distances measured by the device based on the reflection of the optical pulse over consecutive distance measurements by the device; and

a controller configured to generate a first control signal and a second control signal based on the parameter, the first control signal being configured to set the timing budget and the ranging period for a subsequent transmission of the optical pulse by the laser, the second control signal being configured to control operation of an electronic device communicatively coupled to the controller.

27. A method, comprising:

transmitting an optical pulse in accordance with a timing budget and a ranging period, the timing budget corresponding to a duration in time during which a distance is measured from a device to a target, the ranging period corresponding to a period of time between consecutive distance measurements;

receiving a reflection of the optical pulse;

determining a parameter corresponding to a quantitative change in the distance between the device and the target, the quantitative change corresponding to distances measured by the device based on the reflection of the optical pulse over consecutive distance measurements by the device; and

generating a first control signal based on the parameter, the first control signal used to set the timing budget and the ranging period for a subsequent transmission of an optical pulse.