Passive-optical locator

• US 20070103673A1
• Filed: 07/07/2006
• Published: 05/10/2007
• Est. Priority Date: 11/08/2005
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Ash, William
• Granted Patent: US 7,518,713 B2
• Time in Patent Office: Days
• US Class Current: 356/141.500
• CPC Class Codes: F41G 3/02 using an independent line of sight
• CPC Class Codes: F41G 3/06 with rangefinder rangefinders per se G01C
• CPC Class Codes: G01C 3/32 by focusing the object, e.g. on a ground glass screen
• CPC Class Codes: G01S 11/12 using electromagnetic waves other than radio waves
• CPC Class Codes: G01S 19/51 Relative positioning
• CPC Class Codes: G01S 5/16 using electromagnetic waves other than radio waves

Abstract

A system comprising an imaging device and a passive-optical range-finder to focus, on the imaging device, a magnified image of a target positioned in a focal plane of the passive-optical range-finder. The system receives information indicative of a target type and generates information indicative of an absolute geographic location for the target based on at least the target type and information output by the imaging device.

Claims

1. A system comprising:

an imaging device; and

a passive-optical range-finder to focus, on the imaging device, a magnified image of a target positioned in a focal plane of the passive-optical range-finder;

wherein the system receives information indicative of a target type and generates information indicative of an absolute geographic location for the target based on at least the target type and information output by the imaging device.

2. The system of claim 1, further comprises at least one sensor to generate information indicative of an azimuth and an elevation of an optical axis of the passive optical range-finder, wherein the information indicative of the azimuth and the elevation are used to generate the information indicative of the absolute geographic location for the target.

3. The system of claim 1, wherein the information indicative of the absolute geographic location for the target is generated, at least in part, based on at least one of:

information indicative of a magnification of the magnified image, information indicative of a focal length of the passive-optical range-finder, and information indicative of a geographic location associated with the passive-optical locator.

4. The system of claim 1, further comprising a memory in which a lookup table is stored, wherein the lookup table comprises information about a plurality of target types, wherein the information indicative of the absolute geographic location for the target is generated, at least in part, using at some of the information included in the lookup table.

5. The system of claim 4, wherein the lookup table comprises information indicative of at least one of a height, a width, and a depth of a respective one of the plurality of target types.

6. The system of claim 5, wherein the imaging device comprises an array of imaging elements, wherein the focused magnified image of the target is incident on a set of the imaging elements in order to generate at least a portion of the information output by the imaging device, wherein the system determines at least one of an image height, an image width, and an image depth of the focused magnified image based on the information output by the imaging device, wherein the set of the imaging elements includes one of all of the imaging elements within a field of view of the passive-optical locator and less than all of the imaging elements within the field of view of the passive-optical locator.

7. The system of claim 6, further comprising:

a display communicatively coupled to imaging device to display the magnified image of the target; and

a user input interface to receive the information indicative of the target type.

wherein the system correlates the information indicative of the target type to one of the plurality of target types in the lookup table and uses at least one of the height, the width, and the depth associated with the correlated target type, wherein the system determines a distance to the target based on the focal length of the passive-optical range-finder and at least one of a ratio of the height associated with the correlated target type to the image height, a ratio of the width associated with the correlated target type to the image width, and a ratio of the depth associated with the correlated target type to the image depth, wherein the information indicative of the absolute geographic location for the target is generated, at least in part, based on the distance.

8. The system of claim 6, further comprising pattern-recognition software to determine the target type for the target.

9. The system of claim 6:

wherein the array of imaging elements of known size and spacing along two dimensions;

wherein the set of the imaging elements on which the focused magnified image of the target is incident defines a target outline; and

wherein the focused magnified image of the target is incident on;

all the imaging elements in at least one row of the target outline; and

all the imaging elements in at least one column of the target outline;

wherein the at least one row provides information indicative of one of the image width and the image depth and the at least one column provides information indicative of the image height.

10. A method comprising:

focusing a passive-optical range-finder to focus, on an imaging device, a magnified image of a target positioned in a focal plane of the passive-optical range-finder;

receiving information indicative of a target type; and

generating information indicative of an absolute geographic location for the target based on at least the target type and information output by the imaging device.

11. The method of claim 10, further comprising receiving information indicative of an azimuth and an elevation of an optical axis of the passive optical range-finder, wherein the information indicative of the azimuth and the elevation are used to generate the information indicative of the absolute geographic location for the target.

12. The method of claim 10, wherein the information indicative of the absolute geographic location for the target is generated, at least in part, based on at least one of:

information indicative of a magnification of the magnified image, information indicative of a focal length of the passive-optical range-finder, and information indicative of a geographic location associated with the passive-optical locator.

13. The method of claim 10, further comprising storing a lookup table in a memory, wherein the lookup table comprises information about a plurality of target types, wherein the information indicative of the absolute geographic location for the target is generated, at least in part, using at least some of the information included in the lookup table.

14. The method of claim 13, wherein the lookup table comprises information indicative of at least one of a height, a width, and a depth of a respective one of the plurality of target types.

15. The method of claim 14, wherein the imaging device comprises an array of imaging elements, wherein the focused magnified image of the target is incident on a set of the imaging elements in order to generate at least a portion of the information output by the imaging device, wherein the method further comprises determining at least one of an image height, an image width, and an image depth of the focused magnified image based on the information output by the imaging device, wherein the set of the imaging elements includes one of all of the imaging elements within a field of view of the passive-optical locator and less than all of the imaging elements within the field of view of the passive-optical locator.

16. The method of claim 15, further comprising:

correlating the information indicative of the target type to one of the plurality of target types in the lookup table; and

determining a distance to the target based on the focal length of the passive-optical range-finder and at least one of a ratio of the height associated with the correlated target type to the image height, a ratio of the width associated with the correlated target type to the image width, and a ratio of the depth associated with the correlated target type to the image depth, wherein the information indicative of the absolute geographic location for the target is generated, at least in part, based on the distance.

17. A method comprising:

receiving information indicative of a target type;

generating information indicative of a distance between a target and a passive-optical locator based on the target type;

receiving information indicative of an azimuth and an elevation of a direction to the target;

receiving information indicative of the geographic location of the passive-optical locator; and

generating an absolute geographic location of the target based on at least the information indicative of the distance between a target and a passive-optical locator, the information indicative of an azimuth and an elevation of a direction to the target, and the information indicative of the geographic location of the passive-optical locator.

18. The method of claim 17, wherein generating the information indicative of the distance between the target and the passive-optical locator comprises:

aligning the optical axis of the passive-optical range-finder along a line of sight to the target;

focusing a magnified image of the target on an imaging device located at an image plane of the passive optical range-finder;

obtaining information indicative of a focal length of the passive-optical range-finder;

determining a target height, a target width, and a target depth associated with the target type;

generating information indicative of a magnification based on at least one of a ratio of the target height to an image height, a ratio of the target width to an image width, and a ratio of the target depth to an image depth; and

generating the information indicative of the distance based on the information indicative of the magnification and the information indicative of the focal length.

19. The method of claim 17, wherein receiving the information indicative of the target type comprises comparing the image of the target to a plurality of target images.

20. The method of claim 17, wherein receiving the information indicative of the target type comprise receiving a user input including the information indicative of the target type.