Guidance and targeting system

• US 5,275,354 A
• Filed: 07/13/1992
• Issued: 01/04/1994
• Est. Priority Date: 07/13/1992
• Status: Expired due to Term

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Loral Vought Systems Corporation
• Inventors: Kitahara, Robert T., Minor, Lewis G.
• Primary Examiner(s): Lobo, Ian J.
• Application Number:
  US07/912,914
• Time in Patent Office: 540 Days
• Field of Search: 244/3.17, 244/3.16, 235/411, 235/412, 364/423, 382/1, 382/48, 356/5, 356/3
• US Class Current: 244/3.17
• CPC Class Codes: F41G 7/2226 comparing the observed data with stored target data, e.g. target configuration data
• CPC Class Codes: F41G 7/2253 Passive homing systems, i.e. comprising a receiver and do not requiring an active illumination of the target
• CPC Class Codes: F41G 7/2293 using electromagnetic waves other than radio waves
• CPC Class Codes: G01S 17/66 Tracking systems using electromagnetic waves other than radio waves
• CPC Class Codes: G01S 17/89 for mapping or imaging
• CPC Class Codes: G01S 7/4802 using analysis of echo signal for target characterisation; Target signature; Target cross-section
• CPC Class Codes: G06V 20/64 Three-dimensional objects

Abstract

The invention provides a method and apparatus for recognizing physical objects, such as targets, through three dimensional image sensing. A three dimensional sensor, such as a solid-state LADAR sensor, is utilized to establish a three dimensional image of an object or target. The target will be identified or recognized in reference to a two dimensional digital representation of the object taken from a first eye point. A sensor field of view anticipated to include the object will be transformed such that sensed data is viewed from the perspective of the eye point from which the reference image was established. Selected surfaces or contours of the two dimensional image and the transformed image are then compared to identify the object or target in question.

Claims

1. A method of recognizing a selected physical object through three dimensional image sensing, comprising the steps of:

identifying selected surfaces of said object from a two dimensional image of said object, said two dimensional image established from a first eye point;

actuating a sensor to establish a three dimensional image of said object, said sensor defining a second eye point from which said three dimensional image is sensed;

transforming said sensed three dimensional image to form a transformed image of said object, as sensed portions of said object would be viewed from said first eye point; and

matching said selected surfaces of said two dimensional image to surfaces of said transformed image to identify said object.

2. The method of claim 1, wherein said two dimensional image is formed at least in part from a digitized photograph of said object.

3. The method of claim 1, wherein said sensor comprises a solid-state LADAR sensor.

4. The method of claim 1, wherein said sensor is mounted in a housing moving generally toward said object, and wherein said step of transforming said three dimensional image is performed repeatedly.

5. The method of claim 1, wherein said step of transforming said three dimensional image comprises adjusting the scale of said sensed image.

17. The method of claim 1, wherein intensity images are interpreted as three dimensional surfaces by using the range image.

6. A method of target identification for use with air-conveyed weapons, comprising the steps of:

establishing a two dimensional image on said target, said two dimensional image established from a first eye point;

establishing a three dimensional image of an area which includes said target, and said three dimensional image established through use of a LADAR sensor, said three dimensional image established from a second eye point;

transforming said three dimensional sensed image to an image configured as if said three dimensional sensed image had been established from said first eye point; and

matching said transformed image to said two dimensional image to identify said target.

7. The method of claim 6, wherein said step of establishing a two dimensional image of said target comprises the steps of:

establishing a photograph of said target; and

digitizing said photograph.

8. The method of claim 6, wherein said established three dimensional image comprises the use of said LADAR sensor to define a three dimensional edge representation of said target for both range and intensity edges.

9. The method of claim 6, wherein said step of establishing a three dimensional image comprises the step of utilizing said LADAR sensor to establish three dimensional intensity data of surfaces of said target.

10. The method of claim 6, wherein said step of transforming said three dimensional sensed image to form a transformed image comprises the scaling of said sensed three dimensional image.

11. A method of target identification for use in effecting the guidance of an air-conveyed weapon, comprising the steps of:

establishing a digital representation of said target, said digital representation established from a first eye point;

actuating a LADAR sensor in said weapon to establish a three dimensional image of an area which includes said target, said three dimensional image established from a second eye point;

transforming said three dimensional sensed image to a transformed image generally depicting the sensed data of said area including said target as such sensed data would have been sensed from said first eye point;

matching said transformed image to said reference image to identify said target; and

generating an error signal, said error signal communicated to the guidance system of said weapon for controlling the course of said weapon.

12. The method of claim 11, where said established reference image is a two dimensional image.

13. The method of claim 11, wherein said LADAR sensor establishes a three dimensional image including edge boundaries of said sensed area.

14. The method of claim 11, wherein said generated error signal comprises course deviation representations relative to X Y and Z axes in a Cartesian coordinate system.

15. The method of claim 11, wherein said generated error signal includes data representative of angular error.

16. The method of claim 11, wherein said generated error signal contains data representative of angular rate.