Multi-resolution, wide field-of-view, unmanned ground vehicle navigation sensor

• US 9,239,959 B1
• Filed: 04/08/2013
• Issued: 01/19/2016
• Est. Priority Date: 04/08/2013
• Status: Active Grant

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Evans, Bruno J, Cotten, William Dale, Larson, Don Alan
• Primary Examiner(s): Bella, Matthew
• Assistant Examiner(s): HEIDEMANN, JASON E
• Application Number:
  US13/858,366
• Time in Patent Office: 1,016 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G01S 17/89 for mapping or imaging
• CPC Class Codes: G01S 17/931 of land vehicles
• CPC Class Codes: G06V 20/56 exterior to a vehicle by using sensors mounted on the vehicle

Abstract

An imaging system includes: a transmit side that generates a plurality of switched beam laser signals and scans each of the switched beam laser signals into a respective field of view by two polygon facets simultaneously of a polygonal mirror, the respective fields of view overlapping in at least a portion thereof; and a receive side that receives a plurality of reflections of the laser signals, detects them, and captures them as three-dimensional imagery data. A method includes: generating a plurality of switched beam laser signals from a single laser signal; scanning each of the switched beam laser signals in seriatim into a respective field of view by each of two polygonal facets of a polygonal mirror, the respective fields of view overlapping in at least a portion thereof; receiving reflections of the switched beam laser signals; and generating a set of three-dimensional imagery from the received reflections.

Claims

1. An imaging system, comprising:

a polygonal mirror comprising a plurality of reflective polygon facets including a first polygon facet and an adjacent second polygon facet;

a transmit side that generates a plurality of switched beam laser signals and scans the plurality of switched beam laser signals into a first field of view by the first polygon facet and into a second field of view by the second polygon facet, the first field of view and the second field of view forming an overlapping field of view portion that expands in a direction of laser signal propagation, the first field of view further comprising a first non-overlapping field of view portion and the second field of view further comprising a second non-overlapping field of view portion; and

a receive side that receives a plurality of reflections of the plurality of switched beam laser signals, the receive side configured to generate imagery data, based on the plurality of reflections, that has a first resolution of the first non-overlapping field of view portion and the second non-overlapping field of view portion, and a second resolution of the overlapping field of view portion that is a greater resolution than the first resolution.

2. The imaging system of claim 1, wherein each reflective polygon facet of the plurality of reflective polygon facets is at a different angle and, through a single rotation of the polygonal mirror, an entire image frame is captured vertically and horizontally.

3. The imaging system of claim 1, further comprising a computing apparatus including:

a processor, configured to;

control a motor coupled to the polygonal mirror to rotate the polygonal mirror to reflect and scan the plurality of switched beam laser signals;

control the transmit side to generate the plurality of switched beam laser signals and scans; and

control the receive side to generate the imagery data based on the plurality of reflections;

a bus system, communicatively coupled to the processor; and

a storage, communicatively coupled to the bus system, configured to communicate with the processor over the bus system, comprising;

a first software component that, when invoked by the processor over the bus system, configures the processor to control the motor coupled to the polygonal mirror, the transmit side, and the receive side; and

a data structure to store the imagery data.

4. The imaging system of claim 3, the storage further comprising a second software component that, when invoked by the processor over the bus system, configures the processor to:

perform an image recognition on the stored imagery data; and

generate image recognition information based on the imagery data.

5. The imaging system of claim 1, wherein the transmit side comprises:

a laser configured to generate an initial laser signal;

a plurality of transmission paths, each transmission path configured to propagate a switched beam laser signal of the plurality of switched beam laser signals; and

a fiber optic switch configured to switch the initial laser signal to generate the plurality of switched beam laser signals and provide the plurality of switched beam laser signals to the plurality of transmission paths in seriatim;

wherein the polygonal mirror comprises a rotatable polygonal mirror that scans the plurality of switched beam laser signals into the first field of view and the second field of view.

6. The imaging system of claim 1, wherein the transmit side comprises:

a laser configured to generate an initial laser signal;

a plurality of transmission paths, each transmission path configured to propagate a switched beam laser signal of the plurality of switched beam laser signals;

means for generating the plurality of switched beam laser signals from the initial laser signal; and

means for scanning the plurality of switched beam laser signals into the first field of view and the second field of view.

7. The imaging system of claim 1, wherein the plurality of switched beam laser signals has an eye-safe frequency.

8. The imaging system of claim 1, wherein the receive side comprises:

a plurality of receive paths, each receive path comprising an optical detector configured to detect a reflection of the plurality of reflections of switched beam laser signals and to generate a corresponding signal representative thereof;

an optical coupler; and

a plurality of laser receive electronics coupled to the plurality of receive paths by the optical coupler, each laser receive electronics configured to receive a signal representative of a corresponding reflection of the plurality of reflections from a corresponding receive path and to generate a corresponding digital signal representative of the corresponding reflection of the plurality of reflections; and

a plurality of pulse capture electronics, configured to capture the plurality of digital signals as the imagery data.

9. The imaging system of claim 8, wherein the receive side further comprises means for optically aligning the optical detectors.

10. A method, comprising:

generating a plurality of switched beam laser signals from a single laser signal;

scanning each of the switched beam laser signals in seriatim into a first field of view by a first polygon facet of a plurality of polygon facets of a polygonal mirror and into a second field of view by a second polygon facet of the plurality of polygon facets of the polygonal mirror, the first field of view and the second field of view forming an overlapping field of view portion that expands in a direction of laser signal propagation, the first field of view further comprising a first non-overlapping field of view portion and the second field of view further comprising a second non-overlapping field of view portion;

receiving a plurality of reflections of the plurality of switched beam laser signals; and

generating imagery data, based on the plurality of reflections, that has a first resolution of the first non-overlapping field of view portion and the second non-overlapping field of view portion, and a second resolution of the overlapping field of view portion that is a greater resolution than the first resolution.

11. The method of claim 10, wherein the scanning further comprises rotating the polygonal mirror to capture an entire image frame vertically and horizontally, wherein each facet of the plurality of polygon facets is at a different angle.

12. The method of claim 10, further comprising performing image recognition on the imagery data.

13. The method of claim 12, further comprising navigating an unmanned vehicle based on the results of the image recognition.

14. The method of claim 12, wherein

generating the plurality of switched beam laser signals comprises segmenting the switched beam laser signals into a plurality of beamlets;

scanning each of the switched beam laser signals comprises scanning the plurality of beamlets into the first field of view and the second field of view;

receiving the plurality of reflections comprises receiving reflections of the plurality of beamlets; and

generating imagery data comprises generating the imagery data from the reflections of the plurality of beamlets.

15. The method of claim 12, further comprising generating the plurality of switched beam laser signals at an eye-safe frequency.

16. An imaging system, comprising:

a transmit side that generates a plurality of switched beam laser signals and scans the plurality of switched beam laser signals into a first field of view by a first polygon facet of a polygonal mirror and into a second field of view by a second polygon facet of the polygonal mirror, the first field of view and the second field of view forming an overlapping field of view portion that expands in a direction of laser signal propagation, the first field of view further comprising a first non-overlapping field of view portion and the second field of view further comprising a second non-overlapping field of view portion, the transmit side including;

a laser configured to generate an initial laser signal;

a plurality of transmission paths, each transmission path configured to propagate a switched beam laser signal of the plurality of switched beam laser signals;

means for generating the plurality of switched beam laser signals from the initial laser signal; and

the polygonal mirror;

a receive side that receives a plurality of reflections of the plurality of switched beam laser signals, the receive side configured to generate imagery data, based on the plurality of reflections, that has a first resolution of the first non-overlapping field of view portion and the second non-overlapping field of view portion, and a second resolution of the overlapping field of view portion that is a greater resolution than the first resolution;

a processor, configured to;

control a motor coupled to the polygonal mirror to rotate the polygonal mirror to reflect and scan the plurality of switched beam laser signals;

control the transmit side to generate the plurality of switched beam laser signals and scans; and

control the receive side to generate the imagery data based on the plurality of reflections;

a bus system, communicatively coupled to the processor; and

a storage, communicatively coupled to the bus system, configured to communicate with the processor over the bus system, comprising;

a first software component that, when invoked by the processor over the bus system, configures the processor to control the motor coupled to the polygonal mirror, the transmit side, and the receive side; and

a data structure to store the imagery data.

17. The imaging system of claim 16, wherein each reflective polygon facet of a plurality of reflective polygon facets of the polygonal mirror is at a different angle and, through a single rotation of the polygonal mirror, an entire image frame is captured vertically and horizontally.