US 7,549,595 B2
	Rotationally symmetric tags
Paul Lapstun, Balmain (Australia)
Assigned to Silverbrook Research Pty Ltd, Balmain, New South Wales (Australia)
Appl. No. 10/537,159 PCT Filed Dec. 03, 2002, PCT No. PCT/AU02/01634 § 371(c)(1), (2), (4) Date May 31, 2005, PCT Pub. No. WO2004/051557, PCT Pub. Date Jun. 17, 2004.
Prior Publication US 2006/0146069 A1, Jul. 06, 2006
This patent is subject to a terminal disclaimer.
Int. Cl. G06K 19/06 (2006.01); G06K 19/00 (2006.01)

U.S. Cl. 235—494  [235/487]

33 Claims

1. Machine-readable coded data disposed on or in a substrate in accordance with a layout, the layout having six-fold rotational symmetry, the layout including six identical sub-layouts rotated ⅙ revolutions apart about a center of rotational symmetry of the layout, the coded data disposed in accordance with each sub-layout including rotation-indicating data that distinguishes the rotation of that sub-layout from the rotation of at least one other sub-layout within the layout.