US 9,811,757 B2
Histogram methods and systems for object recognition
Ravi K. Sharma, Portland, OR (US)
Assigned to Digimarc Corporation, Beaverton, OR (US)
Filed by Digimarc Corporation, Beaverton, OR (US)
Filed on Aug. 1, 2016, as Appl. No. 15/224,975.
Application 15/224,975 is a continuation of application No. 14/853,408, filed on Sep. 14, 2015, granted, now 9,405,991, issued on Aug. 2, 2016.
Application 14/853,408 is a continuation of application No. 14/321,415, filed on Jul. 1, 2014, granted, now 9,135,520, issued on Sep. 15, 2015.
Application 14/321,415 is a continuation of application No. 13/213,963, filed on Aug. 19, 2011, granted, now 8,767,084, issued on Jul. 1, 2014.
Application 13/213,963 is a continuation of application No. 12/468,402, filed on May 19, 2009, granted, now 8,004,576, issued on Aug. 23, 2011.
Prior Publication US 2017/0032213 A1, Feb. 2, 2017
Int. Cl. G06K 9/00 (2006.01); G06K 9/46 (2006.01); G06K 9/38 (2006.01); G06K 9/62 (2006.01)
CPC G06K 9/4642 (2013.01) [G06K 9/38 (2013.01); G06K 9/4652 (2013.01); G06K 9/6212 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method comprising the acts:
determining, for each of plural pixels in a received input image, three data, the first datum indicating a value of a first color parameter at said pixel, the second datum indicating a value of a second color parameter at said pixel, and the third datum indicating a value of a luminance parameter at said pixel;
generating a histogram for the received input image, said histogram comprising (a) first data indicating a count of pixels in the received input image having said determined first datum within each of M quantized first color parameter value ranges, (b) second data indicating a count of pixels in the received input image having said determined second datum within each of M quantized second color parameter value ranges, and (c) third data indicating a count of pixels in the received input image having said determined third datum within each of N quantized luminance parameter ranges; and
comparing the generated histogram against a collection of reference histograms to identify a reference histogram that corresponds to the generated histogram, to thereby identify the input image;
wherein at least said act of generating the histogram is performed by a cell phone that includes a programmable device that executes software instructions read from a memory, a camera, a touchscreen and a display; and
N is less than half of M.