	US 7,532,768 B2
	Method of estimating an affine relation between images
Kieran Gerard Larkin, Putney (Australia); and Peter Alleine Fletcher, Rozelle (Australia)
Assigned to Canon Kabushiki Kaisha, Tokyo (Japan)
Appl. No. 10/569,972 PCT Filed Nov. 04, 2004, PCT No. PCT/AU2004/001532 § 371(c)(1), (2), (4) Date Oct. 13, 2006, PCT Pub. No. WO2005/045763, PCT Pub. Date May 19, 2005.
Claims priority of application No. 2003906082 (AU), filed on Nov. 04, 2003.
Prior Publication US 2007/0092159 A1, Apr. 26, 2007
Int. Cl. G06K 9/36 (2006.01); G06K 9/00 (2006.01); G09G 5/00 (2006.01)

U.S. Cl. 382—276 [382/100; 345/648; 345/619]

12 Claims

1. A method of detecting an affine relation between a first image and a second image, said first and second images each having a line structure with at least four non-parallel straight lines intersecting each other in at least three points on each line, said method comprising the steps of:

selecting two segments of each line, said segments being defined by the at least three intersection points on the line;

determining a first set of ratios from the selected segments of each line of the first image;

determining a second set of ratios from the selected segments of each line of the second image; and

comparing the first set of ratios to the second set ratios so as to at least determine if an affine relation exists between the line structure of the first image and the line structure of the second image wherein the above steps are performed by a processor.