IMAGE STABILIZATION SYSTEM

• US 20110226955A1
• Filed: 01/04/2011
• Published: 09/22/2011
• Est. Priority Date: 07/01/2005
• Status: Active Grant

• Current Assignee: Teledyne FLIR LLC (Teledyne Technologies Incorporated)
• Original Assignee: FLIR Systems, Inc. (Teledyne Technologies Incorporated)
• Inventors: Dickerson, Bruce A., Luty, Clifford J., Miller, John L., Ellison, Bruce
• Granted Patent: US 9,298,014 B2
• Time in Patent Office: Days
• US Class Current: 250/353
• CPC Class Codes: G02B 17/06 using mirrors only , i.e. having only one curved mirror used in non-imaging applications G02B19/00
• CPC Class Codes: G02B 27/644 compensating for large deviations, e.g. maintaining a fixed line of sight while a vehicle on which the system is mounted changes course
• CPC Class Codes: G02B 27/648 for automatically maintaining a reference alignment, e.g. in self-levelling surveying instruments surveying instruments per se G01C
• CPC Class Codes: G03B 15/006 Apparatus mounted on flying objects
• CPC Class Codes: G03B 5/00 Adjustment of optical system relative to image or object surface other than for focusing
• CPC Class Codes: H04N 23/6812 based on additional sensors, e.g. acceleration sensors
• CPC Class Codes: H04N 23/685 performed by mechanical compensation

Abstract

Imaging systems in which an undedicated optical component—i.e., a component that would be present in the system even in the absence of image stabilization—is configured to undergo corrective motion and/or other correction of image data, and thus to function as a stabilization component. The stabilization component may be a mirror and/or a lens, and a positioner may be provided to tilt, rotate, and/or otherwise precisely adjust the position and orientation of the stabilization component to improve image resolution, compensate for platform motions such as platform vibration, and/or improve image tracking. Because an undedicated optical component functions as the stabilization component, the stabilization occurs upstream, rather than downstream, from separation (if any) of the incoming image data into two or more beams. As a result, only one stabilization component is required regardless of whether the system is configured to split the image data into multiple data channels, and imaging systems as described herein therefore may be particularly well-suited for integration into a shared-aperture imaging system. In some embodiments, the coefficients of thermal expansion of selected system components—including optics, optical support structures, and/or positioners—may be substantially the same or closely matched.

Claims

1. An image stabilization system, comprising:

a primary mirror configured to receive incoming image data and reflect the image data toward a secondary mirror;

a secondary mirror positioned to receive image data reflected by the primary mirror and reflect the image data toward a tertiary mirror;

a tertiary mirror positioned to receive image data reflected by the secondary mirror and reflect the image data toward a detector;

a positioner configured to adjust position and orientation of at least one of the primary, secondary, or tertiary mirrors;

an electronic controller configured to control motions of the positioner; and

a sensing device configured to sense vibration of a platform to which the system is mounted, and to transmit data corresponding to the vibration to the controller to compensate for vibration of a platform upon which the system is mounted;

wherein the primary mirror defines a first axis, and wherein the secondary mirror defines a second axis forming a nonzero intersecting angle with the first axis.

2. The system of claim 1, wherein the sensing device is a gyroscope attached to the platform.

3. The system of claim 1, wherein the sensing device is an inertial measurement unit attached to the platform.

4. The system of claim 1, wherein the platform is an aircraft.

5. The imaging system of claim 1, wherein the positioner is configured to make precise adjustments in position and orientation of the tertiary mirror.

6. The imaging system of claim 1, wherein the positioner is further configured to facilitate tracking a moving target with the imaging system.

7. The imaging system of claim 1, wherein the positioner is further configured to correct alignment errors in the imaging system.

8. The imaging system of claim 1, wherein the positioner is further configured to compensate for atmospheric effects.

9. The imaging system of claim 1, wherein the positioner includes a first piezoelectric device operatively coupled to a top portion of the at least one mirror, and a second piezoelectric device operatively coupled to a bottom portion of the at least one mirror.

10. The imaging system of claim 9, wherein the first and second piezoelectric devices are configured to selectively move the at least one mirror linearly, and are further configured to selectively tilt the at least one mirror.

11. The imaging system of claim 1, wherein the positioner includes a deformable top portion of the at least one mirror, and a deformable bottom portion of the at least one mirror.

12. The imaging system of claim 1, further comprising a beamsplitter configured to receive the image data reflected by the tertiary mirror and to split the image data into a first beam of at least substantially visible light, and a second beam of at least substantially infrared light.

13. The imaging system claim 12, further comprising:

a visible light detector configured to receive the first beam and to translate the first beam into a first image signal; and

an infrared detector configured to receive the second beam and to translate the second beam into a second image signal.

40. The imaging system of claim 1, wherein the positioner is constructed from a material having a first coefficient of thermal expansion and at least one mirror configured to be adjusted by the positioner is constructed from a material having a second coefficient of thermal expansion, and wherein the first and second coefficients of thermal expansion are matched.

14. A corrective imaging system, comprising:

a primary mirror configured to receive and reflect incoming image data;

a secondary mirror positioned to receive and reflect image data reflected by the primary mirror;

a tertiary mirror positioned to receive and reflect image data reflected by the secondary mirror; and

a positioner configured to make precise adjustments in position and orientation of at least one of the primary, secondary, or tertiary mirrors;

wherein the primary mirror defines a first axis, and wherein the secondary mirror defines a second axis forming a nonzero intersecting angle with the first axis; and

wherein the positioner is constructed from a material having a first coefficient of thermal expansion and at least one mirror configured to be adjusted by the positioner is constructed from a material having a second coefficient of thermal expansion, and wherein the first and second coefficients of thermal expansion are matched.

15. The imaging system of claim 14, further comprising an optical support structure configured to hold and support the associated mirror(s), wherein the coefficients of thermal expansion of the positioner, the mirror(s) configured to be adjusted by the positioner, and the optical support structure are matched.

16. The imaging system of claim 14, wherein the coefficients of thermal expansion of the positioner, primary mirror, secondary mirror, and tertiary mirror are matched.

17. The imaging system of claim 14, wherein the mirror(s) configured to be adjusted by the positioner are formed of silicon carbon.

18. The imaging system of claim 14, wherein the positioner is formed of a nickel-steel alloy.

19. The imaging system of claim 18, wherein the nickel-steel alloy is 39Ni/Fe.

20-39. -39. (canceled)