Laser microphone utilizing speckles noise reduction

• US 10,327,069 B2
• Filed: 07/21/2016
• Issued: 06/18/2019
• Est. Priority Date: 07/26/2015
• Status: Expired due to Fees

• Current Assignee: Vocalzoom Systems Ltd.
• Original Assignee: Vocalzoom Systems Ltd.
• Inventors: Fishman, Tal, Blumkin, Alexander, Elhamias, Reuven, Levy, Gil, Bakish, Tal
• Primary Examiner(s): Laekemariam, Yosef K
• Application Number:
  US15/512,564
• Publication Number:
  US 20180139534A1
• Time in Patent Office: 1,062 Days
• Field of Search: 381 13, 381 711, 381 941, 381 93, 381 949, 381 85, 381 96, 381 95, 381170, 381172, 381317
• CPC Class Codes: G10L 21/0216 characterised by the method used for estimating noise
• CPC Class Codes: H04R 17/02 Microphones
• CPC Class Codes: H04R 19/04 Microphones H04R19/01 takes precedence
• CPC Class Codes: H04R 23/008 using optical signals for detecting or generating sound
• CPC Class Codes: H04R 23/02 Transducers using more than one principle simultaneously
• CPC Class Codes: H04R 2410/05 Noise reduction with a separate noise microphone
• CPC Class Codes: H04R 2499/11 Transducers incorporated or for use in hand-held devices, e.g. mobile phones, PDA's, camera's
• CPC Class Codes: H04R 2499/13 Acoustic transducers and sound field adaptation in vehicles
• CPC Class Codes: H04R 2499/15 Transducers incorporated in visual displaying devices, e.g. televisions, computer displays, laptops
• CPC Class Codes: H04R 3/005 for combining the signals of two or more microphones specially adapted for hearing aids H04R25/407

Abstract

A system includes a laser microphone or laser-based microphone or optical microphone. The laser microphone includes a laser transmitter to transmit an outgoing laser beam towards a face of a human speaker. The laser transmitter acts also as a self-mix interferometry unit that receives the optical feedback signal reflected from the face of the human speaker, and generates an optical self-mix signal by self-mixing interferometry of the laser power and the received optical feedback signal; and a speckles noise reducer to reduce speckles noise and to increase a bandwidth of the optical self-mix signal. The speckles noise reducer optionally includes a vibration unit or displacement unit, to cause vibrations or displacement of one or more mirrors or optics elements of the laser microphone, to thereby reduce speckles noise. The speckles noise reducer optionally includes a dynamic laser modulation modifier unit, to dynamically modify modulation properties of a laser modulator associated with the laser transmitter; optionally by modifying an operating temperature of the laser. Optionally, modifications are performed based on a timing scheme, or based on a pseudo-random scheme, or based on a calibration process that selects an advantageous modification scheme. Optionally, the system detects self-mix signal magnitude or bandwidth or quality, and activates the speckles noise reduction mechanism if the self-mix signal appears to be weak or low-quality.

Claims

1. A system comprising:

a laser microphone comprising;

(a) a self-mix interferometry unit, (i) to transmit via a laser transmitter an outgoing laser beam towards a face of the human speaker, and (ii) to receive an optical feedback signal reflected from the face of the human speaker, and (iii) to generate an optical self-mix signal by self-mixing interferometry of the laser power and the received optical feedback signal;

(b) a speckles noise reducer to reduce speckles noise and to increase a bandwidth of said optical self-mix signal;

wherein the speckles noise reducer comprises a self-mix dynamic modulation modifier unit, to dynamically modify a modulation of said laser transmitter, wherein modulation of said laser transmitter reduces speckles noise of said optical self-mix signal.

2. The system of claim 1,

wherein the system comprises a movable beam-splitter that is co-located in proximity to said laser transmitter and to said self-mix interferometry unit, to split one or more laser beams generated by said laser transmitter;

wherein the speckles noise reducer comprises a beam-splitter vibration controller to selectively cause said movable beam-splitter to vibrate, wherein vibrations of said movable beam-splitter reduce speckles noise of said optical self-mix signal.

3. The system of claim 1,

wherein the system comprises a movable beam-splitter that is co-located in proximity to said laser transmitter and to said self-mix interferometry unit, to split one or more laser beams generated by said laser transmitter;

wherein the speckles noise reducer comprises a beam-splitter vibration controller to selectively cause said movable beam-splitter to vibrate based on a pre-defined timing scheme, wherein vibrations of said movable beam-splitter reduce speckles noise of said optical self-mix signal.

4. The system of claim 1,

wherein the system comprises a movable beam-splitter that is co-located in proximity to said laser transmitter and to said self-mix interferometry unit, to split one or more laser beams generated by said laser transmitter;

wherein the speckles noise reducer comprises a beam-splitter displacement controller to selectively cause said movable beam-splitter to move in a non-vibrating pattern, wherein displacement of said movable beam-splitter reduces speckles noise of said optical self-mix signal.

5. The system of claim 1,

wherein the system comprises a movable Micro-Electro-Mechanical Systems (MEMS) beam-splitter that is co-located in proximity to said laser transmitter and to said self-mix interferometry unit, to split one or more laser beams generated by said laser transmitter;

wherein the speckles noise reducer comprises a beam-splitter vibration controller to selectively cause said movable MEMS beam-splitter to vibrate, wherein vibrations of said movable MEMS beam-splitter reduce speckles noise of said optical self-mix signal.

6. The system of claim 1,

wherein the system comprises a movable Micro-Electro-Mechanical Systems (MEMS) beam-splitter that is co-located in proximity to said laser transmitter and to said self-mix interferometry unit, to split one or more laser beams generated by said laser transmitter;

wherein the speckles noise reducer comprises a beam-splitter vibration controller to selectively cause said movable MEMS beam-splitter to vibrate based on a pre-defined timing scheme, wherein vibrations of said movable MEMS beam-splitter reduce speckles noise of said optical self-mix signal.

7. The system of claim 1,

wherein the system comprises a movable Micro-Electro-Mechanical Systems (MEMS) beam-splitter that is co-located in proximity to said laser transmitter and to said self-mix interferometry unit, to split one or more laser beams generated by said laser transmitter;

wherein the speckles noise reducer comprises a beam-splitter displacement controller to selectively cause said movable MEMS beam-splitter to move in a non-vibrating pattern, wherein displacement of said movable beam-splitter reduces speckles noise of said optical self-mix signal.

8. The system of claim 1,

wherein the system comprises a movable beam-steering unit that is co-located in proximity to said laser transmitter and to said self-mix interferometry unit, to steer one or more laser beams generated by said laser transmitter;

wherein the speckles noise reducer comprises a beam-steering unit vibration controller to selectively cause said movable beam-steering unit to vibrate based on a pseudo-random vibration pattern, wherein vibrations of said movable beam-steering unit reduce speckles noise of said optical self-mix signal.

9. The system of claim 1,

wherein the system comprises a movable beam-steering unit that is co-located in proximity to said laser transmitter and to said self-mix interferometry unit, to steer one or more laser beams generated by said laser transmitter;

wherein the speckles noise reducer comprises a beam-steering unit vibration controller to selectively cause said movable beam-steering unit to vibrate based on a pre-defined timing scheme, wherein vibrations of said movable beam-steering unit reduce speckles noise of said optical self-mix signal;

wherein the speckles noise reducer further comprises a calibration unit, to check an effect of at least two timing schemes on speckles noise reduction, and to select a particular timing scheme that provides a greater reduction in speckles noise.

10. The system of claim 1,

wherein the system comprises a movable beam-steering unit that is co-located in proximity to said laser transmitter and to said self-mix interferometry unit, to steer one or more laser beams generated by said laser transmitter;

wherein the speckles noise reducer comprises a beam-steering unit vibration controller to selectively cause only said movable beam-steering unit to vibrate, wherein other components of the laser microphone are maintained non-vibrating;

wherein vibrations of said movable beam-steering unit reduce speckles noise of said optical self-mix signal.

11. The system of claim 1,

wherein the system comprises a movable Micro-Electro-Mechanical Systems (MEMS) beam-steering unit that is co-located in proximity to said laser transmitter and to said self-mix interferometry unit, to steer one or more laser beams generated by said laser transmitter;

wherein the speckles noise reducer comprises a beam-steering unit vibration controller to selectively cause said movable MEMS beam-steering unit to vibrate based on a pseudo-random vibration pattern, wherein vibrations of said movable MEMS beam-steering unit reduce speckles noise of said optical self-mix signal.

12. The system of claim 1,

wherein the system comprises a movable Micro-Electro-Mechanical Systems (MEMS) beam-steering unit that is co-located in proximity to said laser transmitter and to said self-mix interferometry unit, to steer one or more laser beams generated by said laser transmitter;

wherein the speckles noise reducer comprises a beam-steering unit vibration controller to selectively cause said movable MEMS beam-steering unit to vibrate based on a pre-defined timing scheme, wherein vibrations of said movable MEMS beam-steering unit reduce speckles noise of said optical self-mix signal;

wherein the speckles noise reducer further comprises a calibration unit, to check an effect of at least two timing schemes on speckles noise reduction, and to select a particular timing scheme that provides a greater reduction in speckles noise.

13. The system of claim 1,

wherein the system comprises a movable Micro-Electro-Mechanical Systems (MEMS) beam-steering unit that is co-located in proximity to said laser transmitter and to said self-mix interferometry unit, to steer one or more laser beams generated by said laser transmitter;

wherein the speckles noise reducer comprises a beam-steering unit vibration controller to selectively cause only said movable MEMS beam-steering unit to vibrate, wherein other components of the laser microphone are maintained non-vibrating;

wherein vibrations of said movable MEMS beam-steering unit reduce speckles noise of said optical self-mix signal.

14. The system of claim 1,

wherein the system comprises a movable MEMS mirror that is co-located in proximity to said laser transmitter and to said self-mix interferometry unit;

wherein the speckles noise reducer comprises a mirror vibration controller to selectively cause said movable MEMS mirror to vibrate based on a pseudo-random vibration pattern, wherein vibrations of said movable MEMS mirror reduce speckles noise of said optical self-mix signal.

15. The system of claim 1,

wherein the system comprises a movable MEMS mirror that is co-located in proximity to said laser transmitter and to said self-mix interferometry unit;

wherein the speckles noise reducer comprises a mirror vibration controller to selectively cause said movable MEMS mirror to vibrate based on a pre-defined timing scheme, wherein vibrations of said movable MEMS mirror reduce speckles noise of said optical self-mix signal;

wherein the speckles noise reducer further comprises a calibration unit, to check an effect of at least two timing schemes on speckles noise reduction, and to select a particular timing scheme that provides a greater reduction in speckles noise.

16. The system of claim 1,

wherein the system comprises a movable Micro-Electro-Mechanical Systems (MEMS) mirror that is co-located in proximity to said laser transmitter and to said self-mix interferometry unit;

wherein the speckles noise reducer comprises a mirror vibration controller to selectively cause only said movable MEMS mirror to vibrate, wherein other components of the laser microphone are maintained non-vibrating;

wherein vibrations of said movable MEMS mirror reduce speckles noise of said optical self-mix signal.

17. The system of claim 1,

wherein the self-mix dynamic modulation modifier unit is to dynamically modify the modulation of said laser transmitter in accordance with a pre-defined timing scheme,

wherein modulation of said laser transmitter in accordance with said pre-defined timing scheme reduces speckles noise of said optical self-mix signal.

18. The system of claim 1,

wherein the self-mix dynamic modulation modifier unit is to dynamically modify the modulation of said laser transmitter in accordance with a pre-defined timing scheme,

wherein modulation of said laser transmitter in accordance with said pre-defined timing scheme reduces speckles noise of said optical self-mix signal;

wherein the speckles noise reducer further comprises a calibration unit, to check an effect of at least two timing schemes on speckles noise reduction, and to select a particular timing scheme that provides a greater reduction in speckles noise.

19. The system of claim 1,

wherein the self-mix dynamic modulation modifier unit is to dynamically modify the modulation of said laser transmitter in accordance with a pseudo-random modification scheme,

wherein modulation of said laser transmitter in accordance with said pseudo-random modification scheme reduces speckles noise of said optical self-mix signal.

20. The system of claim 1,

wherein the self-mix dynamic modulation modifier unit is to dynamically modify the modulation of said laser transmitter, wherein modulation of said laser transmitter reduces speckles noise of said optical self-mix signal;

wherein the self-mix dynamic modulation modifier unit comprises a temperature modifier unit to dynamically modify an operating temperature of a laser modulator of said laser transmitter.

21. The system of claim 1,

wherein the self-mix dynamic modulation modifier unit is to dynamically modify the modulation of said laser transmitter in accordance with a pre-defined timing scheme,

wherein modulation of said laser transmitter in accordance with said pre-defined timing scheme reduces speckles noise of said optical self-mix signal;

wherein the self-mix dynamic modulation modifier unit comprises a temperature modifier unit to dynamically modify an operating temperature of a laser modulator of said laser transmitter;

wherein modification of the operating temperature of said laser modulator causes modification of said modulation of said laser transmitter.

22. The system of claim 1,

wherein the self-mix dynamic modulation modifier unit is to dynamically modify the modulation of said laser transmitter in accordance with a pre-defined timing scheme,

wherein modulation of said laser transmitter in accordance with said pre-defined timing scheme reduces speckles noise of said optical self-mix signal;

wherein the speckles noise reducer further comprises a calibration unit, to check an effect of at least two timing schemes on speckles noise reduction, and to select a particular timing scheme that provides a greater reduction in speckles noise;

wherein the self-mix dynamic modulation modifier unit comprises a temperature modifier unit to dynamically modify an operating temperature of a laser modulator of said laser transmitter;

wherein modification of the operating temperature of said laser modulator causes modification of said modulation of said laser transmitter.

23. The system of claim 1,

wherein the self-mix dynamic modulation modifier unit is to dynamically modify the modulation of said laser transmitter in accordance with a pseudo-random modification scheme,

wherein modulation of said laser transmitter in accordance with said pseudo-random modification scheme reduces speckles noise of said optical self-mix signal;

wherein the self-mix dynamic modulation modifier unit comprises a temperature modifier unit to dynamically modify an operating temperature of a laser modulator of said laser transmitter;

wherein modification of the operating temperature of said laser modulator causes modification of said modulation of said laser transmitter.

24. The system of claim 1,

wherein the system comprises a movable Micro-Electro-Mechanical Systems (MEMS) beam-splitter that is co-located in proximity to said laser transmitter and to said self-mix interferometry unit, to split one or more laser beams generated by said laser transmitter;

wherein the speckles noise reducer comprises a beam-splitter vibration controller to selectively cause said movable MEMS beam-splitter to vibrate, wherein vibrations of said movable MEMS beam-splitter reduce speckles noise of said optical self-mix signal;

wherein the speckles noise reducer further comprises a self-mix dynamic modulation modifier unit, to dynamically modify a modulation of said laser transmitter, wherein modulation of said laser transmitter further reduces speckles noise of said optical self-mix signal.

25. The system of claim 1, comprising:

a self-mix signal quality estimator, (I) to estimate the bandwidth of the self-mix signal, and (b) if the bandwidth of the self-mix signal is greater than a threshold value, to trigger de-activation of the speckles noise reducer.

26. The system of claim 1, comprising:

a movable beam-splitter that is co-located in proximity to said laser transmitter and to said self-mix interferometry unit, to split one or more laser beams generated by said laser transmitter;

wherein the speckles noise reducer comprises a beam-splitter vibration controller to selectively cause said movable beam-splitter to vibrate, wherein vibrations of said movable beam-splitter reduce speckles noise of said optical self-mix signal,

a self-mix signal quality estimator, (I) to estimate the bandwidth of the self-mix signal, and (b) if the bandwidth of the self-mix signal is lower than a threshold value, to trigger activation of the beam-splitter vibration controller of the speckles noise reducer.

27. The system of claim 1, comprising:

a movable beam-splitter that is co-located in proximity to said laser transmitter and to said self-mix interferometry unit, to split one or more laser beams generated by said laser transmitter;

wherein the speckles noise reducer comprises a beam-splitter vibration controller to selectively cause said movable beam-splitter to vibrate, wherein vibrations of said movable beam-splitter reduce speckles noise of said optical self-mix signal;

a self-mix signal quality estimator, (I) to estimate the bandwidth of the self-mix signal, and (b) if the bandwidth of the self-mix signal is greater than a threshold value, to trigger de-activation of the beam-splitter vibration controller of the speckles noise reducer.

28. The system of claim 1,

further comprising at least one acoustic microphone;

wherein the system is a hybrid acoustic-and-optical sensor.

29. A system comprising:

a laser microphone comprising;

(a) a self-mix interferometry unit, (i) to transmit via a laser transmitter an outgoing laser beam towards a face of the human speaker, and (ii) to receive an optical feedback signal reflected from the face of the human speaker, and (iii) to generate an optical self-mix signal by self-mixing interferometry of the laser power and the received optical feedback signal;

(b) a speckles noise reducer to reduce speckles noise and to increase a bandwidth of said optical self-mix signal;

(c) a self-mix signal quality estimator, (I) to estimate the bandwidth of the self-mix signal, and (b) if the bandwidth of the self-mix signal is lower than a threshold value, to trigger activation of the speckles noise reducer.

30. The system of claim 29,

wherein the system comprises a movable beam-splitter that is co-located in proximity to said laser transmitter and to said self-mix interferometry unit, to split one or more laser beams generated by said laser transmitter;

wherein the speckles noise reducer comprises a beam-splitter vibration controller to selectively cause said movable beam-splitter to vibrate based on a pseudo-random vibration pattern, wherein vibrations of said movable beam-splitter reduce speckles noise of said optical self-mix signal.

31. The system of claim 29,

wherein the system comprises a movable beam-splitter that is co-located in proximity to said laser transmitter and to said self-mix interferometry unit, to split one or more laser beams generated by said laser transmitter;

wherein the speckles noise reducer comprises a beam-splitter vibration controller to selectively cause said movable beam-splitter to vibrate based on a pre-defined timing scheme, wherein vibrations of said movable beam-splitter reduce speckles noise of said optical self-mix signal;

wherein the speckles noise reducer further comprises a calibration unit, to check an effect of at least two timing schemes on speckles noise reduction, and to select a particular timing scheme that provides a greater reduction in speckles noise.

32. The system of claim 29,

wherein the system comprises a movable beam-splitter that is co-located in proximity to said laser transmitter and to said self-mix interferometry unit, to split one or more laser beams generated by said laser transmitter;

wherein the speckles noise reducer comprises a beam-splitter vibration controller to selectively cause only said movable beam-splitter to vibrate, wherein other components of the laser microphone are maintained non-vibrating;

wherein vibrations of said movable beam-splitter reduce speckles noise of said optical self-mix signal.

33. The system of claim 29,

wherein the system comprises a movable Micro-Electro-Mechanical Systems (MEMS) beam-splitter that is co-located in proximity to said laser transmitter and to said self-mix interferometry unit, to split one or more laser beams generated by said laser transmitter;

wherein the speckles noise reducer comprises a beam-splitter vibration controller to selectively cause said movable MEMS beam-splitter to vibrate based on a pseudo-random vibration pattern, wherein vibrations of said movable MEMS beam-splitter reduce speckles noise of said optical self-mix signal.

34. The system of claim 29,

wherein the system comprises a movable Micro-Electro-Mechanical Systems (MEMS) beam-splitter that is co-located in proximity to said laser transmitter and to said self-mix interferometry unit, to split one or more laser beams generated by said laser transmitter;

wherein the speckles noise reducer comprises a beam-splitter vibration controller to selectively cause said movable MEMS beam-splitter to vibrate based on a pre-defined timing scheme, wherein vibrations of said movable MEMS beam-splitter reduce speckles noise of said optical self-mix signal;

wherein the speckles noise reducer further comprises a calibration unit, to check an effect of at least two timing schemes on speckles noise reduction, and to select a particular timing scheme that provides a greater reduction in speckles noise.

35. The system of claim 29,

wherein the system comprises a movable Micro-Electro-Mechanical Systems (MEMS) beam-splitter that is co-located in proximity to said laser transmitter and to said self-mix interferometry unit, to split one or more laser beams generated by said laser transmitter;

wherein the speckles noise reducer comprises a beam-splitter vibration controller to selectively cause only said movable MEMS beam-splitter to vibrate, wherein other components of the laser microphone are maintained non-vibrating;

wherein vibrations of said movable MEMS beam-splitter reduce speckles noise of said optical self-mix signal.

36. The system of claim 29,

wherein the system comprises a movable beam-steering unit that is co-located in proximity to said laser transmitter and to said self-mix interferometry unit, to steer one or more laser beams generated by said laser transmitter;

wherein the speckles noise reducer comprises a beam-steering unit vibration controller to selectively cause said movable beam-steering unit to vibrate based on a pre-defined timing scheme, wherein vibrations of said movable beam-steering unit reduce speckles noise of said optical self-mix signal.

37. The system of claim 29,

wherein the system comprises a movable beam-steering unit that is co-located in proximity to said laser transmitter and to said self-mix interferometry unit, to steer one or more laser beams generated by said laser transmitter;

wherein the speckles noise reducer comprises a beam-steering unit displacement controller to selectively cause said movable beam-steering unit to move in a non-vibrating pattern, wherein displacement of said movable beam-steering unit reduces speckles noise of said optical self-mix signal.

38. The system of claim 29,

wherein the system comprises a movable Micro-Electro-Mechanical Systems (MEMS) beam-steering unit that is co-located in proximity to said laser transmitter and to said self-mix interferometry unit, to steer one or more laser beams generated by said laser transmitter;

wherein the speckles noise reducer comprises a beam-steering unit vibration controller to selectively cause said movable MEMS beam-steering unit to vibrate, wherein vibrations of said movable MEMS beam-steering unit reduce speckles noise of said optical self-mix signal.

39. The system of claim 29,

wherein the system comprises a movable Micro-Electro-Mechanical Systems (MEMS) beam-steering unit that is co-located in proximity to said laser transmitter and to said self-mix interferometry unit, to steer one or more laser beams generated by said laser transmitter;

wherein the speckles noise reducer comprises a beam-steering unit vibration controller to selectively cause said movable MEMS beam-steering unit to vibrate based on a pre-defined timing scheme, wherein vibrations of said movable MEMS beam-steering unit reduce speckles noise of said optical self-mix signal.

40. The system of claim 29,

wherein the system comprises a movable Micro-Electro-Mechanical Systems (MEMS) beam-steering unit that is co-located in proximity to said laser transmitter and to said self-mix interferometry unit, to steer one or more laser beams generated by said laser transmitter;

wherein the speckles noise reducer comprises a beam-steering unit displacement controller to selectively cause said movable MEMS beam-steering unit to move in a non-vibrating pattern, wherein displacement of said movable MEMS beam-steering unit reduces speckles noise of said optical self-mix signal.

41. The system of claim 29,

wherein the system comprises a movable Micro-Electro-Mechanical Systems (MEMS) mirror that is co-located in proximity to said laser transmitter and to said self-mix interferometry unit;

wherein the speckles noise reducer comprises a mirror vibration controller to selectively cause said movable mirror to vibrate, wherein vibrations of said mirror reduce speckles noise of said optical self-mix signal.

42. The system of claim 29,

wherein the system comprises a movable MEMS mirror that is co-located in proximity to said laser transmitter and to said self-mix interferometry unit;

wherein the speckles noise reducer comprises a mirror vibration controller to selectively cause said movable MEMS mirror to vibrate based on a pre-defined timing scheme, wherein vibrations of said movable MEMS mirror reduce speckles noise of said optical self-mix signal.

43. The system of claim 29,

wherein the system comprises a movable MEMS mirror that is co-located in proximity to said laser transmitter and to said self-mix interferometry unit;

wherein the speckles noise reducer comprises a mirror displacement controller to selectively cause said movable MEMS mirror to move in a non-vibrating pattern, wherein displacement of said movable MEMS mirror reduces speckles noise of said optical self-mix signal.

44. The system of claim 29,

wherein the system comprises a movable beam-splitter that is co-located in proximity to said laser transmitter and to said self-mix interferometry unit, to split one or more laser beams generated by said laser transmitter;

wherein the speckles noise reducer comprises a beam-splitter vibration controller to selectively cause said movable beam-splitter to vibrate, wherein vibrations of said movable beam-splitter reduce speckles noise of said optical self-mix signal;

wherein the speckles noise reducer further comprises a self-mix dynamic modulation modifier unit, to dynamically modify a modulation of said laser transmitter, wherein modulation of said laser transmitter further reduces speckles noise of said optical self-mix signal.

45. The system of claim 29,

further comprising at least one acoustic microphone;

wherein the system is a hybrid acoustic-and-optical sensor which is comprised in a device selected from the group consisting of;

a laptop computer, a smartphone, a tablet, a portable electronic device, a vehicular audio system.

46. A system comprising:

a laser microphone comprising;

(a) a self-mix interferometry unit, (i) to transmit via a laser transmitter an outgoing laser beam towards a face of the human speaker, and (ii) to receive an optical feedback signal reflected from the face of the human speaker, and (iii) to generate an optical self-mix signal by self-mixing interferometry of the laser power and the received optical feedback signal;

(b) a speckles noise reducer to reduce speckles noise and to increase a bandwidth of said optical self-mix signal;

wherein the system comprises a movable beam-steering unit that is co-located in proximity to said laser transmitter and to said self-mix interferometry unit, to steer one or more laser beams generated by said laser transmitter;

wherein the speckles noise reducer comprises a beam-steering unit vibration controller to selectively cause said movable beam-steering unit to vibrate, wherein vibrations of said movable beam-steering unit reduce speckles noise of said optical self-mix signal.

47. The system of claim 46,

wherein the speckles noise reducer comprises a self-mix dynamic modulation modifier unit, to dynamically modify a modulation of said laser transmitter, wherein modulation of said laser transmitter reduces speckles noise of said optical self-mix signal;

wherein the system comprises a self-mix signal quality estimator, (I) to estimate the bandwidth of the self-mix signal, and (b) if the bandwidth of the self-mix signal is lower than a threshold value, to trigger activation of the self-mix dynamic modulation modifier unit of the speckles noise reducer.

48. The system of claim 46,

wherein the speckles noise reducer comprises a self-mix dynamic modulation modifier unit, to dynamically modify a modulation of said laser transmitter, wherein modulation of said laser transmitter reduces speckles noise of said optical self-mix signal;

wherein the system comprises a self-mix signal quality estimator, (I) to estimate the bandwidth of the self-mix signal, and (b) if the bandwidth of the self-mix signal is greater than a threshold value, to trigger de-activation of the self-mix dynamic modulation modifier unit of the speckles noise reducer.