Efficient lidar with flexible target interrogation pattern

• US 20060227317A1
• Filed: 04/06/2005
• Published: 10/12/2006
• Est. Priority Date: 04/06/2005
• Status: Active Grant

• Current Assignee: Lockheed Martin Postal Technologies Inc (Opex Corporation)
• Original Assignee: Lockheed Martin Postal Technologies Inc (Opex Corporation)
• Inventors: Suni, Paul J.M., Henderson, Sammy W.
• Granted Patent: US 7,532,311 B2
• Time in Patent Office: Days
• US Class Current: 356/28
• CPC Class Codes: G01B 11/026 by measuring distance between sensor and object G01B11/0608 takes precedence
• 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 7/4817 relating to scanning

Abstract

A system for observing a field of view including a light transmitter and a light detector. A path is defined between the transmitter and the detector. The light transmitter generates substantially coherent light onto a transmit portion of a light path and the light detector is positioned in a receive portion of the light path defined by reflected light from some of the target locations. The system includes a component for configuring at least a portion of the light path such that a subset of the plurality of potential target points are included in the light path.

Claims

1. A system for observing a field of view, wherein the field of view comprises a plurality of potential target points, the system comprising:

a transmitter;

a detector, wherein a path is defined between the transmitter and the detector;

wherein the transmitter generates electromagnetic (EM) energy into a transmit portion of the path;

wherein the detector is positioned in a receive portion of the path defined by reflected EM energy from some of the target locations; and

means for configuring at least a portion of the path such that a subset of the plurality of potential target points are included in the path.

2. The system of claim 1 wherein the transmitter generates energy in a portion of the electromagnetic spectrum ranging from far infrared to extreme ultraviolet.

3. The system of claim 1 wherein the means for configuring comprises a beam forming element positioned in the transmit portion of the path.

4. The system of claim 3 wherein the beam forming element illuminates a selected subset of the plurality of potential target points in the field of view.

5. The system of claim 3 wherein the beam forming element alters one or more characteristics of the EM energy selected from the group consisting of:

direction, phase, frequency, amplitude and polarization.

6. The system of claim 1 wherein the means for configuring comprises a beam forming element positioned in the receive portion of the path.

7. The system of claim 6 wherein the detector comprises a plurality of detector elements and the beam forming element directs the receive portion of the path to a selected subset of a plurality of detector elements.

8. The system of claim 6 wherein the detector comprises a plurality of detector elements and the beam forming element alters one or more characteristics of the reflected EM energy selected from the group consisting of:

direction, phase, frequency, amplitude and polarization.

9. The system of claim 1 further comprising a signal processor coupled to the detector and operable to process signals generated by the detector.

10. The system of claim 1 further comprising a signal processor coupled to the detector and operable to process signals generated by the detector, wherein the detector comprises a plurality of detector elements and wherein the signal processor is coupled to the means for configuring at least a portion of the path to select a subset of the detector elements for processing.

11. The system of claim 1 further comprising a local oscillator (LO) laser beam aligned with the return portion of the path to implement coherent detection.

12. The system of claim 11 wherein the LO uses the means for configuring at least a portion of the path.

13. The system of claim 1 further comprising a second means for configuring at least a portion of the path, wherein the LO uses the second means for configuring.

14. The system of claim 1 wherein the means for configuring at least a portion of the path comprises fixed passive elements.

15. The system of claim 1 wherein the means for configuring at least a portion of the path comprises switchable passive elements.

16. The system of claim 1 wherein the means for configuring at least a portion of the path comprises active elements.

17. The system of claim 1 wherein the means for configuring at least a portion of the path comprises a device selected from the group consisting of:

liquid crystal array, deformable mirror, micro-mirror array, micro-prism array, transmissive phase control devices, diffractive optical devices, refractive optical devices and holograms.

18. The system of claim 1 wherein the detector comprises a number of elements that is larger than the number in the subset of the plurality of potential target points.

19. The system of claim 1 wherein the detector comprises a number of elements that is substantially equal to the number in the subset of the plurality of potential target points.

20. The system of claim 1 wherein the detector comprises a number of elements that is less than the number in the subset of the plurality of potential target points.

21. A method for observing a field of view, wherein the field of view comprises a plurality of potential target points, the method comprising:

transmitting electromagnetic (EM) energy into a transmit portion of a path;

directing the light path to the field of view, wherein some of the EM energy in the path is reflected to form a reflected portion of the path;

detecting the reflected EM energy; and

configuring at least a portion of the path such that a subset of the plurality of potential target points are included in the path.

22. A method comprising using the method of claim 21 to determine a characteristic of an object in the field of view.

23. The method of claim 22 wherein the characteristic is selected from the group consisting of:

range, speed, velocity, acceleration, direction of motion, vibration, texture, reflectivity, color, dimension and shape.

24. The method of claim 21 wherein the act of configuring at least a portion of the path comprises:

configuring the transmit portion of the path to direct the path to only selected location in the field of view.

25. The method of claim 21 wherein the act of configuring at least a portion of the path comprises:

configuring the receive portion of the path to direct the receive portion of the path to selected portions of a detector used to perform the detecting.

26. The method of claim 21 wherein the act of configuring the path comprises altering one or more characteristics of the EM energy selected from the group consisting of:

direction, phase, frequency, amplitude and polarization.

27. The method of claim 21 wherein the transmitter generates energy in a portion of the electromagnetic spectrum, the spectrum ranging from far infrared to extreme ultraviolet.