Optical Jitter Estimation

• US 20200137280A1
• Filed: 10/29/2019
• Published: 04/30/2020
• Est. Priority Date: 10/29/2018
• Status: Abandoned Application

• Current Assignee: The Government Of The United States Of America, As Represented By The Secretary Of The Navy
• Original Assignee: The Government Of The United States Of America, As Represented By The Secretary Of The Navy
• Inventors: Yingling, Adam J.
• Application Number:
  US16/667,304
• Publication Number:
  US 20200137280A1
• Time in Patent Office: Days
• CPC Class Codes: G03B 43/00 Testing correct operation of photographic apparatus or parts thereof
• CPC Class Codes: G06T 7/136 involving thresholding
• CPC Class Codes: G06T 7/20 Analysis of motion motion estimation for coding, decoding, compressing or decompressing digital video signals H04N19/43, H04N19/51
• CPC Class Codes: G06T 7/66 of image moments or centre of gravity
• CPC Class Codes: H04N 23/6811 based on the image signal
• CPC Class Codes: H04N 23/6842 by controlling the scanning position, e.g. windowing
• CPC Class Codes: H04N 23/689 Motion occurring during a rolling shutter mode

Abstract

According to one aspect of the invention, a method of estimating optical jitter, the methods comprising the steps of: capturing an image in a series of consecutive frames; iteratively characterizing one or more optical parameters of the captured image over the consecutive frames; and based on the one or more optical parameters, executing time domain analysis to decompose optical disturbance into drift and jitter.

Claims

1. A method of estimating optical jitter, the methods comprising the steps of:

capturing an image in a series of consecutive frames;

iteratively characterizing one or more optical parameters of the captured image over the consecutive frames; and

based on the one or more optical parameters, executing time domain analysis to decompose optical disturbance into drift and jitter.

2. The method of claim 1, wherein the one or more optical parameters include a centroid of the image.

3. The method of claim 1, wherein the image is an image of an impinging laser.

4. The method of claim 1, further comprising the step of stacking consecutive frames and determining centroid movement over a time step defined by a frame rate and number of images stacked.

5. The method of claim 1, further comprising the step of isolating the captured image by cropping to an area the laser image will appear, applying a threshold to the cropped image, and utilizing binary masking to isolate content in the captured image.

6. The method of claim 1, wherein the step of executing time domain analysis includes determining line of sight disturbance by measuring changes in centroid location and shape of a laser spot in the captured image.

7. The method of claim 1, wherein drift is found as a linear fit through an integration window defined by a subset of sequential frames.

8. The method of claim 1, wherein jitter is found by removing drift and computing a root-mean square value of residual offsets from drift.

9. The method of claim 1, using a rolling integration window technique.

10. The method of claim 1, further including the step of obtaining spectral responses of the one or more optical parameters.

11. The method of claim 10, further comprising the step of correlating the spectral responses with known modes to identify sources of disturbance.

12. The method of claim 1, further comprising the steps of:

storing drift and jitter in arrays for each of a plurality of rolling integration windows;

computing an average and standard deviation of drift and jitter from the arrays; and

determining success or failure of pointing stability for an imaging system by comparing the average plus a predetermined multiple of the standard deviation to a predetermined threshold.