Image plane sensor alignment system and method

Patent metadata

Field	Value
Publication number	US-9689669-B2
Application number	US-201514685921-A
Country	US
Kind code	B2
Filing date	Apr 14, 2015
Priority date	Apr 14, 2015
Publication date	Jun 27, 2017
Grant date	Jun 27, 2017

Abstract

System and method for sensor alignment. In one example, a reimaging optical system includes reimaging foreoptics positioned to receive and reimage incident electromagnetic radiation to produce an intermediate image plane and output an optical beam of the received incident electromagnetic radiation, an imaging optical apparatus positioned to receive the optical beam and focus the electromagnetic radiation of the optical beam onto a first focal plane, a first imaging sensor positioned at the first focal plane and configured to produce a first image responsive to receiving the electromagnetic radiation of the optical beam, an alignment object selectively positioned at the intermediate image plane and configured to superimpose an alignment tool upon the first image, and a controller coupled to the first imaging sensor and configured to perform an alignment process for the first imaging sensor based on at least a position of the alignment tool in the first image.

First claim

What is claimed is:

1. A reimaging optical system comprising:
reimaging foreoptics positioned to receive and reimage incident electromagnetic radiation to produce an intermediate image plane and output an optical beam of the received incident electromagnetic radiation;
an imaging optical apparatus positioned to receive and focus the optical beam onto a first focal plane;
a first imaging sensor positioned at the first focal plane and configured to produce a first image responsive to receiving the optical beam;
an alignment object selectively positioned at the intermediate image plane and configured to superimpose an alignment tool upon the first image; and
a controller coupled to the first imaging sensor and configured to perform an alignment process for the first imaging sensor based on at least a position of the alignment tool in the first image.

2. The system according to claim 1 , wherein the reimaging foreoptics comprises a front objective and a first optical component, and wherein the intermediate image plane is interposed between the front objective and the first optical component.

3. The system according to claim 2 , wherein the front objective comprises at least one optical element positioned to focus the electromagnetic radiation onto the intermediate image plane.

4. The system according to claim 3 , wherein the reimaging foreoptics comprises a beam steering mirror configured to aim the electromagnetic radiation to substantially position the alignment tool in a field of view of the first imaging sensor.

5. The system according to claim 1 , wherein the alignment object is fixed at the intermediate image plane and the alignment process for the first imaging sensor includes pixel substitution.

6. The system according to claim 1 , wherein the alignment object includes a plurality of focus indicators, individual ones of the plurality of focus indicators disposed at varying depths of the intermediate image plane;
wherein, the controller is further configured to perform a focus process for the first imaging sensor based on at least a focus of individual ones of the plurality of focus indicators.

7. The system according to claim 6 , wherein the plurality of focus indicators includes a plurality of discrete protrusions extending from a frame of the alignment object.

8. The system according to claim 1 , further comprising a second imaging sensor positioned at a second focal plane and configured to produce a second image responsive to receiving the optical beam, wherein the alignment object is further configured to superimpose the alignment tool upon the second image.

9. The system according to claim 8 , wherein the second imaging sensor includes a plurality of imaging sensors positioned at a plurality of focal planes and configured to produce a plurality of images responsive to receiving the optical beam, wherein the alignment object is further configured to superimpose the alignment tool upon the plurality of images.

10. The system according to claim 8 , wherein the controller is further coupled to the second imaging sensor and configured to perform the alignment process for the second imaging sensor based on a position of the alignment tool in the second image and the position of the alignment tool in the first image, wherein the alignment process for the second imaging sensor includes determining an offset between the alignment tool superimposed upon the first image and the alignment tool superimposed upon the second image.

11. The system according to claim 10 , wherein the controller is further configured to align the first imaging sensor and second imaging sensor to an optical transmitter responsive to determining an offset between the alignment tool superimposed upon the first image and the alignment tool superimposed upon the second image.

12. The system according to claim 10 , wherein the first imaging sensor is responsive to light in a first spectral band and the second imaging sensor is responsive to light in a second spectral band, and the imaging optical apparatus further comprises a dichroic beam splitter positioned to receive the optical beam and partition the electromagnetic radiation of the optical beam to the first imaging sensor and the second imaging sensor based on the first and second spectral bands.

13. The system according to claim 1 , wherein the alignment tool includes a reticle.

14. The system according to claim 13 , wherein the reticle includes a grid having a plurality of longitudinal and latitudinal extending delineations defined by a substantially square profile.

15. The system according to claim 1 , wherein the reimaging foreoptics further comprises at least one pivot and the alignment object is configured to rotate about the pivot and extend into the intermediate image plane in real-time.

16. The system according to claim 1 , further comprising at least one illumination source positioned to substantially illuminate the alignment object.

17. An optical alignment method comprising:
receiving and reimaging electromagnetic radiation incident on reimaging foreoptics configured to produce an intermediate image plane and output an optical beam;
receiving and focusing the electromagnetic radiation of the optical beam onto a first focal plane;
producing a first image with a first imaging sensor positioned at the first focal plane responsive to receiving the electromagnetic radiation of the optical beam;
selectively positioning an alignment object having an alignment tool at the intermediate image plane to superimpose the alignment tool upon the first image; and
performing an alignment process for the first imaging sensor based on at least a position of the alignment tool in the first image.

18. The method according to claim 17 , further comprising aiming the electromagnetic radiation to substantially position the alignment object in a field of view of the first imaging sensor.

19. The method according to claim 17 , wherein the alignment object is fixed at the intermediate image plane and performing the alignment process for the first imaging sensor includes performing pixel substitution.

20. The method according to claim 17 , further comprising producing a second image with a second imaging sensor positioned at a second focal plane responsive to receiving the electromagnetic radiation of the optical beam, and wherein selectively positioning an alignment object having an alignment tool at the intermediate image plane includes selectively positioning an alignment object having an alignment tool at the intermediate image plane to superimpose the alignment tool upon the first image and the second image.

21. The method according to claim 20 , further comprising performing an alignment process for the second imaging sensor based on a position of the alignment tool in the second image and a position of the alignment tool in the first image.

22. The method according to claim 21 , wherein the alignment process for the second imaging sensor includes determining an offset between the alignment tool superimposed upon the first image and the alignment tool superimposed upon the second image.

23. The method according to claim 17 , further comprising performing a focus process for the first imaging sensor based on at least a focus of individual ones of a plurality of focus indicators of the alignment object positioned at the intermediate image plane.

24. The method according to claim 23 , wherein the focus process includes reposit

Assignees

• Raytheon Co

Inventors

• Ross Jr Thomas William
• Miles Steven A
• Mann David C
• Avila Marco A
• McDonald David Russell
• Gallagher Jeffery M

Classifications

• H04N23/673

  based on contrast or high frequency components of image signals, e.g. hill climbing method · CPC title

• H04N23/45

  for generating image signals from two or more image sensors being of different type or operating in different modes, e.g. with a CMOS sensor for moving images in combination with a charge-coupled device [CCD] for still images · CPC title

• G01J3/0237 Primary

  Adjustable, e.g. focussing · CPC title

• G01J1/0266

  Field-of-view determination; Aiming or pointing of a photometer; Adjusting alignment; Encoding angular position; Size of the measurement area; Position tracking; Photodetection involving different fields of view for a single detector · CPC title

• H04N17/002

  for television cameras · CPC title