PERSONAL LADAR SENSOR

• US 20130242283A1
• Filed: 03/16/2012
• Published: 09/19/2013
• Est. Priority Date: 03/16/2012
• Status: Active Grant

• Current Assignee: Continental Autonomous Mobility US LLC (Continental AG)
• Original Assignee: Advanced Scientific Concepts, Inc.
• Inventors: Bailey, Howard, Gilliland, Patrick, Short, Brad, Stettner, Roger, Goldstein, Barton, Heughebaert, Laurent, Spagnolia, Joseph
• Granted Patent: US 8,804,101 B2
• Time in Patent Office: Days
• US Class Current: 356/4.01
• CPC Class Codes: G01S 17/89 for mapping or imaging
• CPC Class Codes: G01S 7/4813 Housing arrangements
• CPC Class Codes: G01S 7/4816 of receivers alone
• CPC Class Codes: G01S 7/486 Receivers

Abstract

A lightweight, low volume, inexpensive LADAR sensor incorporating 3-D focal plane arrays is adapted specifically for personal electronic appliances. The present invention generates, at high speed, 3-D image maps and object data at short to medium ranges. The techniques and structures described may be used to extend the range of long range systems as well, though the focus is on compact, short to medium range ladar sensors suitable for use in personal electronic devices. 3-D focal plane arrays are used in a variety of physical configurations to provide useful new capabilities to a variety of personal electronic appliances.

Claims

1. An apparatus for personal scene detection comprising:

a personal ladar sensor with a field of view and a wavelength of operation having

a semiconductor laser with a modulated laser light output and a diffusing optic for illuminating a scene in the field of view of said personal ladar sensor,

a two dimensional array of light sensitive detectors positioned at a focal plane of a light collecting and focusing system, each of said light sensitive detectors with an output producing an electrical response signal from a reflected portion of said modulated laser light output,

a readout integrated circuit with a plurality of unit cell electrical circuits, each of said unit cell electrical circuits having an input connected to one of said light sensitive detector outputs, each said unit cell electrical circuit having an electrical response signal demodulator and a range measuring circuit connected to an output of said electrical response signal demodulator, said range measuring circuit further connected to a reference signal providing a zero range reference for the said modulated laser light output,

a detector bias circuit connected to at least one voltage distribution grid of said array of light sensitive detectors, and a temperature stabilized frequency reference;

said personal ladar sensor mounted inside a radome attached to a personal electronic device, said radome comprising at least one transparent surface capable of transmitting light at said wavelength of operation.

2. The apparatus of claim 1 wherein said personal electronic device is selected from the set comprising a cell phone, a handheld personal digital assistant (PDA), a still camera, a video camera, a headgear, a helmet, a portable computer, a tablet computer.

3. The apparatus of claim 1 wherein said personal electronic device further comprises a voice communications link.

4. The apparatus of claim 1 wherein said personal electronic device further comprises a visual feedback device.

5. The apparatus of claim 4 wherein said visual feedback device comprises a flat panel display.

6. The apparatus of claim 1 wherein said personal electronic device further comprises a visible light camera.

7. The apparatus of claim 1 wherein said light collecting and focusing system is a zoom lens.

8. The apparatus of claim 7 wherein said zoom lens further comprises a piezoelectric actuator.

9. The apparatus of claim 7 wherein said zoom lens further comprises a deformable refracting element.

10. The apparatus of claim 9 wherein said deformable refracting element is a microfluidic lens.

11. The apparatus of claim 1 wherein said semiconductor laser is a vertical cavity surface emitting laser.

12. The apparatus of claim 11 wherein said vertical cavity surface emitting laser is a hybrid structure comprised of a plurality of substrates bonded together.

13. The apparatus of claim 1 wherein said modulated laser light output is modulated with a waveform selected from the set of a single Gaussian pulse profile, multiple Gaussian profile pulses, a single flat-topped pulse profile, multiple flat-topped pulses, a pulsed sinewave and a chirped sinewave pulse.

14. The apparatus of claim 13 wherein said waveform is multiple Gaussian profile pulses and said multiple Gaussian profile pulses are encoded using a Barker code.

15. The apparatus of claim 13 wherein said waveform is multiple flat-topped pulses and said multiple flat-topped pulses are encoded using a Barker code.

16. The apparatus of claim 1 wherein said two dimensional array of light sensitive detectors is mounted directly to said readout integrated circuit.

17. The apparatus of claim 1 wherein said two dimensional array of light sensitive detectors is formed on the surface of said readout integrated circuit using at least one compound containing quantum dots.

18. The apparatus of claim 1 wherein said two dimensional array of light sensitive detectors is formed on a surface of said readout integrated circuit using a plurality of nanostructures selected from the set of nanofilms, nanoflakes, nanoplates, nanopillars, nanotubes, nanoshells, and nanorods.

19. The apparatus of claim 1 wherein said electrical response signal demodulator comprises:

an input amplifier with an output connected to a trigger circuit;

a series of analog sampling gates, each sampling gate with an associated analog memory cell,

a sample clock controlling the timing of each of said sampling gates,

a selector for selecting each of said sampling gates in sequence,

a counter for counting the number of samples,

an output amplifier with an input connected to each of said analog memory cells,

an output control for selecting a sequence of said analog memory cell contents to be output through said output amplifier,

and wherein an input of an external analog to digital converter is connected to said output amplifier, an output of said analog to digital converter is connected to an input of a digital processor and produces a sequence of digitized analog samples of said electrical response signal, and said digital processor is programmed to demodulate said electrical response signal by operating on the sequence of digitized analog samples using a digital processing algorithm.

20. The apparatus of claim 1 wherein said electrical response signal demodulator comprises:

an input amplifier with an output connected to a first input of a phase comparator, said phase comparator having a first phase reference signal connected to a second input, an output of said phase comparator connected to the input of an integrator, said integrator having an integrator output with an output voltage proportional to the difference in phase between said first input and said second input of said phase comparator.

21. The apparatus of claim 20 wherein said integrator output is further connected to the input of a buffer amplifier, said buffer amplifier having an output connected to a first input of a voltage comparator and to an input of an analog sampling gate, said voltage comparator having a second input connected to a threshold voltage, said sampling gate further having a sample clock input and an output connected to a first analog memory cell, said analog memory cell storing an analog voltage proportional to said difference in phase between said first input and said second input of said phase comparator.

22. The apparatus of claim 20 wherein said input amplifier has an output connected to a first input of a second phase comparator, said second phase comparator having a second input connected to a second phase reference signal, said second phase comparator having an output connected to an input of a second integrator, said second integrator having a second integrator output with an output voltage proportional to the difference in phase between said first input and said second input of said second phase comparator.

23. The apparatus of claim 22 wherein said second integrator output is further connected to an input of a second buffer amplifier, said second buffer amplifier with an output connected to a first input of a second voltage comparator and to an input of a second analog sampling gate, said second voltage comparator having a second input connected to a threshold voltage, and said second sampling gate further having a sample clock input and an output connected to a second analog memory cell, said second analog memory cell storing an analog voltage proportional to said difference in phase between said first input and said second input of said second phase comparator.

24. The personal ladar sensor of claim 22 wherein said second phase reference differs in phase from said first phase reference by a minimum of 45 degrees.

25. The personal ladar sensor of claim 22 wherein said second phase reference differs in phase from said first phase reference by approximately 90 degrees.

26. The personal ladar sensor of claim 21 wherein said first analog memory cell has an output which is sampled by an input of an analog to digital converter, said analog to digital converter having a first digitized output voltage representative of a phase measurement to a first phase reference, said first digitized output voltage connected to an input of a digital processor, said digital processor computing a range to a reflective feature in a scene in the field of view of said personal ladar sensor by using a sequence of digital operations on said first digitized output voltage representative of a phase measurement to a first phase reference.

27. The apparatus of claim 26 wherein said digital processor computes a range to a reflective feature in a scene in the field of view of said personal ladar sensor by using a sequence of digital operations which operate on both said first digitized output voltage representative of a phase measurement to a first phase reference, and a second digitized output voltage representative of a phase measurement to a second phase reference.

28. The apparatus of claim 20 wherein said input amplifier has an output connected to a peak detector circuit.

29. The apparatus of claim 1 wherein said electrical response signal demodulator comprises:

an input amplifier with an output connected to an analog shift register comprised of a plurality of analog sampling gates, each sampling gate with a sample clock input connected to a sample clock output, each of said plurality of analog sampling gates activated in a prearranged, and each sampling gate with an output connected to an analog memory cell, each memory cell with an output connected to an input of a weighting amplifier, an output of each weighting gain amplifier connected to a summing junction, said summing junction having a summing junction output connected to a first input of a voltage comparator, said voltage comparator having a second input connected to a threshold voltage, said voltage comparator having a logic output, said voltage comparator logic output signaling when said summing junction output exceeds said threshold voltage,

a counter connected to said sampling clock output, said counter started counting by a reference signal from said zero range reference, and said counter stopped counting when said voltage comparator logic output signals when said summing junction output exceeds said threshold voltage.

30. The apparatus of claim 29 further comprising a second counter which is started counting when said voltage comparator logic output signals when said summing junction output exceeds said threshold voltage, and said second counter stopped counting when said voltage comparator logic output signals when said threshold voltage exceeds said summing junction output.

31. The apparatus of claim 1 wherein said readout circuit further comprises a plurality of thin film resistors deposited on a surface of said readout integrated circuit.

32. The apparatus of claim 1 wherein said readout circuit further comprises a plurality of thick film resistors deposited on a surface of said readout integrated circuit.

33. The apparatus of claim 1 wherein said readout circuit further comprises a plurality of metal oxide film resistors.

34. The apparatus of claim 1 wherein said readout circuit further comprises a plurality of thin film resistors formed of a metal and ceramic compound.

35. The apparatus of claim 1 wherein said readout circuit further comprises a plurality of thin film resistors, each thin film resistor having a first end connected to an inverting input of an amplifier circuit of said unit cell electrical circuit, and each thin film resistor with a second end connected to an output of said amplifier circuit.

36. The apparatus of claim 1 wherein said readout circuit further comprises a plurality of thick film resistors, each thick film resistor with a first end connected to an inverting input of an amplifier circuit of said unit cell electrical circuit, and each thick film resistor with a second end connected to an output of said amplifier circuit.

37. The apparatus of claim 1 wherein said readout circuit further comprises a plurality of thin film resistors applied via physical vapor deposition to a surface of said readout integrated circuit.

38. The apparatus of claim 1 wherein said readout circuit further comprises a plurality of thick film resistors applied via stencil to a surface of said readout integrated circuit.

39. The apparatus of claim 20 wherein said integrator further incorporates a reset capability.

40. The apparatus of claim 20 wherein said integrator further incorporates a bandwidth control.

41. The apparatus of claim 28 wherein said peak detector incorporates a reset capability.

42. The apparatus of claim 28 wherein said peak detector further incorporates a bandwidth control.

66. The apparatus of claim 1 wherein said personal electronic device further comprises an audio feedback device.

67. The apparatus of claim 66 wherein said audio feedback device is a headphone.

68. The apparatus of claim 66 wherein said audio feedback device is a hearing aid type.

69. The apparatus of claim 66 wherein said audio feedback device is worn in the ear canal.

70. The apparatus of claim 66 wherein said audio feedback device is a cochlear implant.

71. The apparatus of claim 1 wherein said light collecting and focusing system comprises at least one diffractive optic.

72. The apparatus of claim 1 wherein said modulated laser light output is modulated with a pulsed sinewave, and said pulsed sinewave may be switched between a plurality of frequencies.

45. A personal ladar sensor with a field of view and a wavelength of operation mounted to a personal electronic device, and said personal ladar sensor being mounted inside a radome attached to said personal electronic device, and said radome comprising at least one transparent surface capable of transmitting light at said wavelength of operation, said personal ladar sensor further comprising a semiconductor laser with a modulated laser light output and a diffusing optic for illuminating a scene and at least one light reflecting feature in the field of view of said personal ladar sensor, and a two dimensional array of light sensitive detectors positioned at a focal plane of a light collecting and focussing system, and each of said light sensitive detectors with an output producing an electrical response signal from a light signal, and said light signal produced by reflection from a feature in the scene in a field of view of said personal ladar sensor, a readout integrated circuit with a plurality of unit cell electrical circuits, and each of said unit cell electrical circuits with an input connected to one of said light sensitive detector outputs, and said unit cell electrical circuit with an electrical response signal demodulator, and a range measuring circuit connected to an output of said electrical response signal demodulator, and said range measuring circuit further connected to a reference signal providing a zero range reference for said modulated laser light output,

said personal ladar sensor further comprising a detector bias circuit connected to at least one voltage distribution grid of said array of light sensitive detectors, and a temperature stabilized frequency reference clock,

said electrical response signal demodulator comprising an input amplifier with an output connected to an analog shift register comprised of a plurality of analog sampling gates, and each sampling gate with an associated analog memory cell, and a sample clock controlling the timing of each of said sampling gates, said sample clock derived from said temperature stabilized frequency reference clock, and a selector for selecting each of said sampling gates in sequence, and a counter for counting the number of samples, and an output amplifier with an input connected to each of said analog memory cells, and an output control for selecting a sequence of said analog memory cell contents to be output through said output amplifier, and further comprising an input of an analog to digital converter connected to said output amplifier, and an output of said analog to digital converter connected to an input of a digital data processor and producing a sequence of digitized analog samples of said electrical response signal, and said digital data processor programmed to demodulate said electrical response signal by operating on aforesaid sequence of digitized analog samples using a digital processing algorithm, and said digital data processor and digital processing algorithm producing a measurement of range to said light reflecting feature in said field of view of said personal ladar sensor.

46. The personal ladar sensor of claim 45 wherein said digital data processor resides on a single silicon substrate, and said digital data processor further comprises at least 100 thousand words of main memory, and said words of main memory at least 32 bits in width.

47. The personal ladar sensor of claim 45 wherein said digital data processor resides on a single silicon substrate, and said digital data processor further comprises a hardware encoded floating point mathematics unit.

48. The personal ladar sensor of claim 45 wherein said digital data processor resides on a single silicon substrate, and said digital data processor further comprises a hardware encoded integer math unit.

49. The personal ladar sensor of claim 45 wherein said digital data processor resides on a single silicon substrate, and said digital data processor further comprises a serial communications port.

50. The personal ladar sensor of claim 45 wherein said serial communications port comprises an Ethernet port.

51. The personal ladar sensor of claim 45 wherein said serial communications port comprises a USB port.

52. The personal ladar sensor of claim 45 wherein said digital data processor resides on a single silicon substrate, and said digital data processor further comprises a parallel communications port.

53. The personal ladar sensor of claim 45 wherein said digital data processor resides on a single silicon substrate, and said digital data processor further comprises a direct memory access capability.

54. A modular ladar sensor with a field of view and a wavelength of operation, said modular ladar sensor further comprising:

a semiconductor laser with a modulated laser light output and a diffusing optic for illuminating a scene in the field of view of said personal ladar sensor, and a two dimensional array of light sensitive detectors positioned at a focal plane of a light collecting and focusing system, and each of said light sensitive detectors with an output producing an electrical response signal from a reflected portion of said modulated laser light output, a readout integrated circuit with a plurality of unit cell electrical circuits, and each of said unit cell electrical circuits with an input connected to one of said light sensitive detector outputs, and said unit cell electrical circuit with an electrical response signal demodulator, and a range measuring circuit connected to an output of said electrical response signal demodulator, and said range measuring circuit further connected to a reference signal providing a zero range reference for said modulated laser light output,

a detector bias circuit connected to at least one voltage distribution grid of said array of light sensitive detectors, and a temperature stabilized frequency reference,

said readout integrated circuit connected to a portable computer at a distal end of a cable, said cable having at least one transmission line within, and said cable further having a plug at a proximal end connecting to said portable computer.

55. The modular ladar sensor of claim 54 wherein said cable further comprises at least one electrical conductor.

56. The modular ladar sensor of claim 54 wherein said cable further comprises at least one fiber optic transmission line.

57. The modular ladar sensor of claim 54 wherein said cable further comprises at least one coaxial transmission line.

58. The modular ladar sensor of claim 54 wherein said cable further comprises at least one twisted pair of electrical conductors comprising a transmission line.

59. The modular ladar sensor of claim 54 wherein a peripheral port of said portable computer provides power to said modular ladar sensor.

60. The modular ladar sensor of claim 59 wherein said peripheral port is selected from the set of a USB port, a serial communications port, a parallel communications port, a network communications port.

61. The modular ladar sensor of claim 54 wherein said peripheral port is an Ethernet port.

65. The modular ladar sensor of claim 54 wherein the cable further comprises at least one coaxial connecting member.

62. A modular ladar sensor with a field of view and a wavelength of operation, said modular ladar sensor further comprising a semiconductor laser with a modulated laser light output and a diffusing optic for illuminating a scene in the field of view of said personal ladar sensor, and a two dimensional array of light sensitive detectors positioned at a focal plane of a light collecting and focussing system, and each of said light sensitive detectors with an output producing an electrical response signal from a reflected portion of said modulated laser light output, a readout integrated circuit with a plurality of unit cell electrical circuits, and each of said unit cell electrical circuits with an input connected to one of said light sensitive detector outputs, and said unit cell electrical circuit with an electrical response signal demodulator, and a range measuring circuit connected to an output of said electrical response signal demodulator, and said range measuring circuit further connected to a reference signal providing a zero range reference for said modulated laser light output,

and said modular ladar sensor further comprising a detector bias circuit connected to at least one voltage distribution grid of said array of light sensitive detectors, and a temperature stabilized frequency reference,

said modular ladar sensor connected through a connector plug to a receptacle of a portable computer, and said connector plug mounted to said modular ladar sensor, and connecting to said receptacle of said portable computer.

63. The modular ladar sensor of claim 62 wherein the connector further comprises at least one electrical conductor.

64. The modular ladar sensor of claim 62 wherein the connector further comprises at least one fiber optic connecting member.