Motion and gesture recognition by a passive thermal sensor system

• US 9,410,848 B2
• Filed: 07/31/2015
• Issued: 08/09/2016
• Est. Priority Date: 03/04/2014
• Status: Active Grant

• Current Assignee: Excelitas Technologies Singapore Pte., Ltd.
• Original Assignee: Excelitas Technologies Singapore Pte., Ltd.
• Inventors: Schilz, Jurgen, Barlow, Arthur, Pandy, Anand
• Primary Examiner(s): Kim, Kiho
• Application Number:
  US14/814,639
• Publication Number:
  US 20150338277A1
• Time in Patent Office: 375 Days
• US Class Current: 1/1
• CPC Class Codes: G01J 5/0025 Living bodies ear thermometers G01J5/0011; detecting, measuring or recording for diagnostic purposes A61B5/00
• CPC Class Codes: G01J 5/10 using electric radiation detectors
• CPC Class Codes: G01P 13/00 Indicating or recording presence, absence, or direction, of movement electric switches H01H; counting moving objects G06M7/00
• 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: G06F 3/0304 Detection arrangements using opto-electronic means constructional details of pointing devices not related to the detection arrangement using opto-electronic means G06F3/033; optical digitisers G06F3/042

Abstract

Systems and methods for recognizing motion made by a moving person are presented. The system includes a thermal sensor configured to generate a low frequency or direct current signal upon receiving thermal energy. A spatially modulating optic is disposed between the thermal sensor and the warm object. The optic is configured to modulate the thermal energy received by the thermal sensor as a function of an orientation of the moving person with respect to the thermal sensor. An electronics unit in communication with the thermal sensor includes a memory and a processor. The processor is configured by the memory to detect a change in the thermal sensor signal and recognize a characteristic of the thermal sensor signal.

Claims

1. A system configured to recognize a movement made by a moving person, comprising:

a thermal sensor configured to generate a low frequency and/or direct current signal upon receiving thermal energy;

a spatially modulating optic disposed between the thermal sensor and the moving person configured to modulate the thermal energy received by the thermal sensor as a function of an orientation of the moving person with respect to the thermal sensor; and

an electronics unit in communication with the thermal sensor, further comprising;

a memory; and

a processor in communication with the memory, the processor configured by the memory to perform steps comprising;

detecting a change in the thermal sensor signal; and

recognizing a characteristic in the thermal sensor signal.

2. The system of claim 1, wherein the thermal sensor is configured to detect radiation having a wavelength at least within the range of 4 μ

m and 20 μ

m.

3. The system of claim 1, wherein the thermal sensor is one of the group consisting of a thermopile, a microelectromechanical (MEMS) infrared sensor, a pyroelectric sensor, a bolometer, an intrinsic infrared semiconductor, and an infrared extrinsic semiconductor.

4. The system of claim 1, wherein the spatially modulating optic comprises one of the group consisting of a ground or molded multi-lens array, a molded Fresnel-lens array, and a combination of a multi-lens and a Fresnel-lens array.

5. The system of claim 1, wherein the spatially modulating optic further comprises one or more of the group consisting of a spatial aperture array with total or partial light exclusion between apertures, a grating, a coding plate or disc.

6. The system of claim 1, wherein the characteristic is detected in the time domain.

7. The system of claim 1, wherein the processor is further configured by the memory to perform steps comprising converting the thermal sensor signal from a time domain signal to a frequency domain signal.

8. The system of claim 7, wherein the characteristic is detected in the frequency domain.

9. The system of claim 7, wherein the characteristic comprises a correlation between a frequency domain event and a time domain event.

10. The system of claim 1, wherein the thermal sensor and the electronics unit are co-located within a single apparatus.

11. The system of claim 1, wherein the thermal sensor, the spatially modulating optic, and the electronics unit are co-located within a single apparatus.

12. The system of claim 1, wherein the thermal sensor and the spatially modulating optic unit are co-located within a single apparatus.

13. A method for recognizing movement of a person moving in a monitored space, comprising the steps of:

receiving incident thermal energy at a modulating optics from a field of view of the modulating optics within the monitored space, wherein the modulating optics comprises a plurality of lenses and/or apertures;

directing the incident thermal energy received by the modulating optics onto a thermal sensing device optically coupled to the modulating optics, wherein the modulating optics is configured to modulate the thermal energy received by the thermal sensing device as a function of an orientation of the moving person with respect to the thermal sensing device;

producing, with the thermal sensing device, a direct current output signal that is sustained at a level proportional to an amount of thermal energy being directed to the thermal sensing device by the modulating optics; and

providing the output signal to an electronics unit in communication with the thermal sensing device, the electronics unit further comprising a memory and a processor in communication with the memory, the processor configured by the memory to perform steps comprising;

isolating a characteristic of the signal; and

comparing the characteristic of the signal to a reference characteristic.

14. The method of claim 13, wherein the modulating optics provides optical zones with varying output signal over the individual zone thus producing alternating regions of relatively high output signal to the incident thermal energy and regions of relatively low output signal to the incident thermal energy.

15. The method of claim 13, wherein the thermal sensing device is selected from the group consisting of a micro-electro-mechanical (MEMs) infrared sensor, a thermopile, a bolometer, pyroelectric and a semiconductor-based infrared sensor.

16. The method of claim 13, wherein the lenses of the modulating optics are selected from the group consisting of Fresnel lens arrays, Fresnel zone arrays, holographic optical elements, diffractive optical elements, refractive optical elements and binary optical elements.

17. The method of claim 13, wherein the spatially modulating optic further comprises one or more of the group consisting of a spatial aperture array with total or partial light exclusion between apertures, a grating, a coding plate or disc.

18. The method of claim 13, wherein the direct current signal output is sustained at a level that is proportional to an amount of thermal energy being directed to the thermal sensing device with a wavelength between 4 μ

m and 20 μ

m.