Ultraviolet, infrared, and near-infrared lidar system and method

• US 7,652,752 B2
• Filed: 07/14/2005
• Issued: 01/26/2010
• Est. Priority Date: 07/14/2005
• Status: Active Grant

• Current Assignee: Arete Associates
• Original Assignee: Arete Associates
• Inventors: Miller, David, Ryder, William L., Fetzer, Gregory J., Gugler, Douglas, Sitter, David N. Jr., Bybee-Driscoll, Shannon, Griffis, Andrew J., Gelbart, Asher
• Primary Examiner(s): Tarcza; Thomas H
• Assistant Examiner(s): Ratcliffe; Luke D
• Application Number:
  US11/181,665
• Publication Number:
  US 20070024840A1
• Time in Patent Office: 1,657 Days
• Field of Search: 356 301- 315, 356 401- 41, 356 501- 515, 356 6- 22
• US Class Current: 356/4.01
• CPC Class Codes: G01S 17/89 for mapping or imaging
• CPC Class Codes: G01S 7/4811 common to transmitter and receiver
• CPC Class Codes: G01S 7/484 Transmitters
• CPC Class Codes: G01S 7/4861 Circuits for detection, sampling, integration or read-out
• CPC Class Codes: G01S 7/487 Extracting wanted echo signals , e.g. pulse detection

Abstract

Pushbroom and flash lidar operations outside the visible spectrum, most preferably in near-IR but also in IR and UV, are enabled by inserting—ahead of a generally conventional lidar receiver front end—a device that receives light scattered from objects and in response forms corresponding light of a different wavelength from the scattered light. Detailed implementations using arrays of discrete COTS components—most preferably PIN diodes and VCSELs, with intervening semicustom amplifiers—are discussed, as is use of a known monolithic converter. Differential and ratioing multispectral measurements, particularly including UV data, are enabled through either spatial-sharing (e. g. plural-slit) or time-sharing.

Claims

1. Apparatus for detecting objects and determining their distance, to form a two-dimensional or three-dimensional image;

said apparatus comprising;

means for receiving light pulses, having pulse width in at least part of the range between one and ten nanoseconds, scattered from such objects;

means, responsive to the receiving means, for forming and emitting corresponding light pulses of a different wavelength from the scattered light;

discrete electronic or other hardware components interconnecting the receiving means with the forming means; and

means for accepting the emitted corresponding light pulses that have left the forming means, and for distributing successive temporal components of said accepted light pulses in a nontemporal domain, to time-resolve the accepted corresponding light pulses to determine respective distances of such objects.

2. The apparatus of claim 1, further for use in determining reflectance of the objects;

and wherein the receiving means and the forming means;

comprise means for measuring and recording gray-level information in the received and formed light; and

are capable of operating at bandwidth exceeding fifty megahertz.

34. The apparatus of claim 1, wherein:

the accepting and distributing means comprise means for time-resolving the accepted corresponding light after that corresponding light is formed and emitted.

38. The apparatus of claim 1, further comprising:

a light source generating light pulses having said pulse width in at least part of the range between one and ten nanoseconds; and

means for projecting said pulses, having said pulse width, from the source generally toward such objects for scattering from such objects toward the receiving means.

39. The apparatus of claim 38, wherein:

the generated light pulses comprise light of a first wavelength; and

said different wavelength of the corresponding light is shorter than said first wavelength.

40. The apparatus of claim 38, wherein:

the receiving means and the forming means operate at bandwidth as high as at least fifty megahertz.

41. The apparatus of claim 1, wherein:

the receiving means and the forming means operate at bandwidth as high as at least fifty megahertz.

3. Apparatus for detecting objects and determining their distance, to form a two-dimensional or three-dimensional image;

said apparatus comprising;

means for receiving light scattered from such objects;

means, responsive to the receiving means, for forming a corresponding light of a different wavelength from the scattered light; and

means for time-resolving the corresponding light to determine respective distances of such objects;

wherein the receiving means and the forming means comprise, respectively;

a first, optointermediate stage that receives the scattered light and in response generates a corresponding intermediate signal; and

a second, intermedioptical stage that receives the intermediate signal and in response forms the corresponding light; and

means for applying gain at one or more of these locations;

the first stage,

the second stage, and

between the first and second stages.

4. The apparatus of claim 3, wherein:

the intermediate signal comprises an optical signal.

5. The apparatus of claim 3, wherein:

the time-resolving means comprise a streak lidar device.

6. The apparatus of claim 3, further comprising:

a light source; and

means for projecting pulses of light from the source toward such objects for scattering back toward the receiving means.

7. The apparatus of claim 3, wherein:

the streak lidar device is incorporated into a repetitively pulsed pushbroom system.

8. The apparatus of claim 7, further comprising:

an aircraft or other vehicle transporting the receiving means, and the forming means, and the streak lidar device relative to such objects.

9. The apparatus of claim 5, wherein:

the streak lidar device comprises a multislit streak tube.

10. The apparatus of claim 3, wherein:

the time-resolving means comprise a flash lidar system.

11. The apparatus of claim 3, wherein:

the intermediate signal comprises an electronic signal;

the first stage comprises an optoelectronic stage; and

the second stage comprises an electrooptical stage.

12. The apparatus of claim 11, wherein:

the optoelectronic stage comprises light-sensitive semiconductor devices.

13. The apparatus of claim 12, wherein:

the semiconductor devices comprise PIN diodes.

14. The apparatus of claim 12, wherein:

the semiconductor devices comprise avalanche photodiodes.

15. The apparatus of claim 13, wherein:

the electrooptical stage comprises vertical-cavity surface-emitting lasers or other collimated-emission devices, connected to receive the electronic signal from the PIN diodes.

16. The apparatus of claim 13, wherein:

the electrooptical stage comprises devices selected from the group consisting of;

edge-emitting lasers,

quantum diodes, and

quantum-dot lasers;

said devices being connected to receive the electronic signal from the PIN diodes.

17. The apparatus of claim 11, wherein:

the electrooptical stage comprises collimating optical emitters connected to receive a signal from the optoelectronic stage.

18. The apparatus of claim 3, further comprising:

utilization means responsive to the time-resolving means.

19. The apparatus of claim 18, wherein the utilization means are selected from the group consisting of:

interpretive means for characterizing such objects based on the time-resolved light;

a monitor that displays an image of such objects for viewing by a person at the apparatus;

a monitor at a base station for reviewing such objects or related data received from the resolving by means by telemetry;

a data-processing device for analyzing such objects or images of them;

automatically operated interpretive modules that determine whether particular conditions are met;

announcement-broadcasting means or other automatic physical apparatus connected to operate in response to the time-resolving means;

means for enabling or denying access to secure facilities through operation of doors and gates, or access to computer systems or to financial services including but not limited to credit or banking;

means for determination of hostile conditions, and resulting security measures including but not limited to automatically deployed area-sealing bulkheads.

20. The apparatus of claim 3, wherein:

the receiving means and forming means comprise discrete arrays of light-sensing and light-producing components respectively.

21. The apparatus of claim 20, further comprising:

a discrete array of circuitry for controlling the forming means in response to the receiving means.

22. The apparatus of claim 3, wherein:

the receiving means and forming means respectively comprise at least one monolithic hybrid of light-sensing and light-producing components.

23. The apparatus of claim 22, wherein:

the monolithic hybrid further comprises circuitry for controlling the forming means in response to the receiving means.

35. The apparatus of claim 3, wherein:

the time-resolving means operate to time-resolve the corresponding light after the forming means form that corresponding light.

42. The apparatus of claim 3, wherein:

the scattered light pulses comprise light of a first wavelength; and

said different wavelength of the corresponding light is shorter than said first wavelength.

24. A method for detecting and ranging objects, said method comprising the steps of:

receiving light pulses, having pulse width in at least part of the range between one and ten nanoseconds, scattered from such objects;

in response to the scattered light, forming corresponding light pulses of a different wavelength from the scattered light;

said receiving step and said forming step being performed in respective discrete electronic components or other hardware components; and

time-resolving the corresponding light to determine respective distances of such objects;

said time-resolving step defining a time interval, for time-resolution of the corresponding light, of one hundred microseconds'"'"' duration, or within an order of magnitude thereof; and

said receiving step and said forming step being substantially capable of continuous operation throughout said time interval.

36. The method of claim 24, wherein:

the time-resolving step occurs after the forming step.

43. The apparatus of claim 24, further comprising:

a light source generating pulses of light, having said pulse width in at least part of the range between one and ten nanoseconds; and

means for projecting said pulses, having said pulse width, from the source generally toward such objects for scattering from such objects toward the receiving means.

44. The apparatus of claim 24, wherein:

the scattered light comprises light of a first wavelength; and

said different wavelength of the corresponding light is shorter than said first wavelength.

25. A method for detecting and ranging objects, and determining their reflectance, said method comprising the steps of:

receiving light pulses, having pulse width in at least part of the range between one and ten nanoseconds, scattered from the objects;

in response to the scattered light, forming corresponding light pulses of a different wavelength from the scattered light; and

time-resolving the corresponding light to determine respective distances of such objects;

said time-resolving step defining a time interval, for time-resolution of the corresponding light, between twenty-five nanoseconds and one hundred microseconds long; and

said receiving step and said forming step being substantially capable of continuous operation throughout said time interval, and being performed in respective discrete electronic or other hardware components; and

wherein;

the receiving step preserves at least some gray-level information in the scattered light; and

the forming step also preserves at least some of the gray-level information.

45. The apparatus of claim 25, further comprising:

a light source generating pulses of light, having said pulse width in at least part of the range between one and ten nanoseconds; and

means for projecting said pulses, having said pulse width, from the source generally toward such objects for scattering from such objects toward the receiving means.

46. The apparatus of claim 45, wherein:

the generated light pulses comprise light of a first wavelength; and

said different wavelength of the corresponding light is shorter than said first wavelength.

26. A method for detecting and ranging objects, said method comprising the steps of:

receiving light scattered from the objects;

in response to the scattered light, forming a corresponding light of a different wavelength from the scattered light; and

after the forming step, time-resolving the corresponding light to determine respective distances of such objects;

wherein;

the receiving step receives the scattered light in plural wavelength bands in the infrared, near-infrared or visible, or combinations of these; and

the forming step forms the corresponding light in substantially a single, common visible wavelength band.

27. The method of claim 26:

further comprising the step of, before the receiving step, transmitting light in plural wavelength bands, substantially simultaneously, toward the objects;

wherein the receiving and forming steps comprise receiving said scattered light in each one of the plural wavelength bands and forming respective plural corresponding lights of respective different wavelengths; and

further comprising the step of accepting the plural corresponding lights of respective different wavelengths at plural slits, respectively, of a plural-slit streak camera.

28. The method of claim 26:

further comprising the step of, before the receiving step, transmitting light in said plural wavelength bands, at respective plural times, toward the objects; and

wherein the receiving step includes receiving the plural wavelength bands at plural times, respectively.

37. The method of claim 26, wherein:

the time-resolving step occurs after the forming step.

29. A method for detecting and ranging objects, said method comprising the steps of:

receiving light scattered from the objects;

in response to the scattered light, forming a corresponding light of a different wavelength from the scattered light; and

time-resolving the corresponding light to determine respective distances of such objects;

wherein;

the receiving step receives the scattered light in plural wavelength bands, and

the forming step forms the corresponding light in substantially a single, common wavelength band;

deriving plural signals from the received light in the plural wavelength bands, respectively; and

finding differences or ratios between signals received in the plural wavelength bands.

30. Apparatus for detecting objects and determining their distance and reflectance, to form a two-dimensional or three-dimensional image;

said apparatus comprising;

a light source;

means for projecting pulses of light from the source toward such objects for scattering by such objects;

means for receiving light scattered by such objects and in response forming a corresponding light of a different wavelength from the scattered light, preserving gray-level information in said received and corresponding light;

means, comprising a streak camera, for time-resolving the corresponding light to determine respective distances and reflectances of such objects;

wherein the receiving-and-forming means comprise;

a first, optoelectronic stage comprising an array of light-sensitive PIN diodes, that receives the scattered light and in response forms a corresponding electronic signal;

a second, electrooptical stage comprising an array of vertical-cavity surface-emitting lasers connected to receive the electronic signal from the PIN diodes, that receives the electronic signal and in response forms the corresponding light; and

an electronic circuit array connecting the electronic signal from the first stage to the second stage, and modifying the signal to operate the second stage.

31. The apparatus of claim 30, wherein:

the streak lidar device is incorporated into a repetitively pulsed pushbroom system.

32. The apparatus of claim 31, further comprising:

an aircraft or other vehicle transporting the receiving-and-forming means and the streak lidar device relative to such objects.

33. The apparatus of claim 32, further comprising:

utilization means responsive to the time-resolving means.