US 12,014,441 B2
Signal processors and methods for estimating geometric transformations of images for digital data extraction
Ravi K. Sharma, Portland, OR (US); John D. Lord, West Linn, OR (US); Robert G. Lyons, Portland, OR (US); Osama M. Alattar, Tigard, OR (US); and Jacob L Boles, Portland, OR (US)
Assigned to Digimarc Corporation, Beaverton, OR (US)
Filed by Digimarc Corporation, Beaverton, OR (US)
Filed on Sep. 20, 2021, as Appl. No. 17/479,910.
Application 17/479,910 is a continuation of application No. 15/967,214, filed on Apr. 30, 2018, granted, now 11,127,105, issued on Sep. 21, 2021.
Application 15/967,214 is a continuation of application No. 15/211,944, filed on Jul. 15, 2016, granted, now 9,959,587, issued on May 1, 2018.
Claims priority of provisional application 62/199,710, filed on Jul. 31, 2015.
Claims priority of provisional application 62/193,479, filed on Jul. 16, 2015.
Prior Publication US 2022/0180466 A1, Jun. 9, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. G06T 1/00 (2006.01); G06T 3/00 (2006.01); G06T 3/02 (2024.01); G06T 3/10 (2024.01)
CPC G06T 1/0064 (2013.01) [G06T 3/02 (2024.01); G06T 3/10 (2024.01); G06T 2201/0052 (2013.01); G06T 2201/0065 (2013.01); G06T 2201/0081 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A method of determining a geometric transform of a reference signal in an image for extracting digital data, the method comprising:
with a programmed processor or digital logic circuit:
for plural reference signal components of a reference signal, transforming coordinates of a reference signal component according to a candidate geometric transform;
measuring correlation between the transformed reference signal component and the image, the measured correlation comprising a combination of complex components of a frequency domain transform of the image at neighboring integer coordinates around the coordinates of the transformed reference signal component, wherein the complex combination combines complex components according to a phase relationship at the neighboring integer coordinates, wherein the phase relationship comprises weighting neighboring integer coordinates according to a point spread function;
updating, based on the measured correlation that is below a threshold, the coordinates of the reference signal component to a location within a neighborhood around the coordinates of the transformed reference signal component;
determining a new geometric transform that transforms the reference signal components to the updated coordinates; and
applying the new geometric transform to extract encoded digital data from the image.