Micro-level polarization and multispectral scanning within an optical objective

Patent metadata

Field	Value
Publication number	US-2021088799-A1
Application number	US-201916582113-A
Country	US
Kind code	A1
Filing date	Sep 25, 2019
Priority date	Sep 25, 2019
Publication date	Mar 25, 2021
Grant date	—

Abstract

The system and method for imaging having filter containing polarized elements, multispectral elements or both being oscillated in circular or linear motion so each individual pixel will view a scene thru the individual filters. The motion of the filter is synchronized with a frame rate of an imager. In one example this is accomplished by micro actuators. Each pixel sampling feeds a processor detection algorithm that determines if a multispectral/polarization signature is present in the scene.

First claim

What is claimed:

1 . A method for polarization scanning within an optical objective comprising:
providing a filter assembly positioned within an objective optic of an imager, wherein the filter assembly comprises a plurality of filter sets, each filter set comprising of a number of different polarization states; providing micro-scanning actuators for moving the filter assembly within the objective optic of the imager; scanning, via filter assembly motion, radiation reflected from a scene wherein the scene is represented by a plurality of pixels on the imager; providing an image frame reference by mapping the pixels, frame by frame, to the scene; collecting contrast samples of individual pixels in the scene via the filter set thereby providing a plurality of filter samples; correlating image frames with a processing unit and using IMU data thus providing a scene registration for the filter samples; aligning the plurality of filter samples; and nulling a vertical and a horizontal pixel motion relative to a ground in the scene.

2 . The method for polarization scanning according to claim 1 , wherein each filter set further comprises a number of different multispectral states.

3 . The method for polarization scanning according to claim 1 , wherein the imager is a LWIR microbolometer.

4 . The method for polarization scanning according to claim 1 , wherein the filter set is a 2×2 pixel filter set and the micro-scanning actuators move in a circular motion.

5 . The method for polarization scanning according to claim 1 , wherein the filter set is a 1×4 pixel filter set and the micro-scanning actuators move in a linear motion.

6 . The method for polarization scanning according to claim 1 , further comprising stabilizing a ground pointing with the micro-scanners via a digital ROIC having the ability to use IMU angular rate data and shift pixel integration from a first pixel to an adjacent pixel mid integration.

7 . The method for polarization scanning according to claim 6 , wherein a single pixel on the ground has polarization or multispectral samples from each of the filter sets that can be compared for use in target identification.

8 . A method for multispectral scanning within an optical objective comprising:
providing a filter assembly positioned within an objective optic of an imager, wherein the filter assembly comprises a plurality of filter sets, at least one filter set comprising of a number of different multispectral states; providing micro-scanning actuators for moving the filter assembly within the objective optic of the imager; scanning, via filter assembly motion, radiation reflected from a scene wherein the scene is represented by a plurality of pixels on the imager; providing an image frame reference by mapping each pixel, frame by frame, to the scene; collecting contrast samples of each pixel in the scene via each filter set, resulting in a plurality of filter samples; correlating image frames with a processing unit and using IMU data thus providing a scene registration for the filter samples; aligning the plurality of filter samples; and nulling a vertical and a horizontal pixel motion relative to a ground in the scene in a dynamic environment.

9 . The method for multispectral scanning according to claim 8 , wherein each filter set further comprises a number of different polarization states.

10 . The method for multispectral scanning according to claim 8 , wherein the imager is a SWIR InGaAs array.

11 . The method for multispectral scanning according to claim 8 , wherein the filter set is a 2×2 pixel filter set and the micro-scanning actuators move in a circular motion.

12 . The method for multispectral scanning according to claim 8 , wherein the filter set is a 1×4 pixel filter set and the micro-scanning actuators move in a linear motion.

13 . The method for multispectral scanning according to claim 8 , further comprising stabilizing a ground pointing with the micro-scanners via a digital ROIC having the ability to use IMU angular rate data and shift pixel integration from a first pixel to an adjacent pixel mid integration.

14 . The method for multispectral scanning according to claim 8 , wherein a single pixel on the ground has polarization or multispectral samples from each of the filter sets that can be compared for use in target identification.

15 . A system for multispectral or polarization scanning, within an optical objective comprising:
an optical objective in an imager; a filter assembly positioned within the objective optic of an imager, wherein the filter assembly comprises a plurality of filter sets, each filter set comprising of a number of different polarization states; micro-scanning actuators for moving the filter assembly within the objective optic of the imager; and a processing unit configured to:
collect a plurality of filter samples from contrast samples of each pixel in the scene via each filter set;
correlate image frames using IMU data for providing a scene registration for each filter sample;
align the plurality of filter samples; and
null a vertical and a horizontal pixel motion relative to a ground in the scene in a dynamic environment.

16 . The system according to claim 15 , wherein each filter set further comprises a number of different multispectral states.

17 . The system according to claim 15 , wherein the filter set is a 2×2 pixel filter set and the micro-scanning actuators move in a circular motion.

18 . The system according to claim 15 , wherein the filter set is a 1×4 pixel filter set and the micro-scanning actuators move in a linear motion.

Assignees

• Bae Sys Inf & Elect Sys Integ

Inventors

• Choiniere Michael J
• Coffey Jay W
• Lane Jason R
• Lange Davis A
• Stockwell Jason T

Classifications

• G02B27/646

  compensating for small deviations, e.g. due to vibration or shake (movement of one or more optical elements for control of motion blur in cameras, projectors or printers G03B2205/0007; image stabilisation in cameras peculiar to the presence or use of an electronic image sensor H04N23/68) · CPC title

• G02B27/286

  for controlling or changing the state of polarisation, e.g. transforming one polarisation state into another (G02B5/3083 takes precedence; light guide coupling means utilising polarising elements G02B6/34) · CPC title

• G02B26/101

  with both horizontal and vertical deflecting means, e.g. raster or XY scanners (colour television using laser beams scanning a display screen H04N9/3129) · CPC title

• G02B5/208

  for use with infrared or ultraviolet radiation, e.g. for separating visible light from infrared and/or ultraviolet radiation · CPC title

• G02B5/201 Primary

  in the form of arrays · CPC title