US 11,816,856 B2
Absolute position detection
Elmar Swiegot, Wertheim (DE); Alan Shinn, Berkeley, CA (US); Chiko Fan, San Jose, CA (US); David King, Pleasanton, CA (US); and Elias Elias, Milton, MA (US)
Assigned to Sage Vision Inc., Milton, MA (US)
Filed by Sage Vision Inc., Milton, MA (US)
Filed on Apr. 2, 2021, as Appl. No. 17/221,623.
Application 17/221,623 is a continuation of application No. 15/884,171, filed on Jan. 30, 2018, granted, now 10,997,742.
Application 15/884,171 is a continuation of application No. 13/918,704, filed on Jun. 14, 2013, abandoned.
Claims priority of provisional application 61/678,581, filed on Aug. 1, 2012.
Claims priority of provisional application 61/660,614, filed on Jun. 15, 2012.
Prior Publication US 2021/0398307 A1, Dec. 23, 2021
This patent is subject to a terminal disclaimer.
Int. Cl. G06T 7/60 (2017.01); G06T 7/73 (2017.01)
CPC G06T 7/60 (2013.01) [G06T 7/73 (2017.01); G06T 2207/10024 (2013.01)] 19 Claims
OG exemplary drawing
 
9. A measurement system for measuring the absolute position of a first object with respect to a second object along an axis of motion representing a direction of relative motion between the first object and the second object, the system comprising:
a scalar element attached to the first object, the scalar element comprising:
a series of regularly repeating optically readable index lines positioned along an axis of the scalar element parallel to the axis of motion, and
a series of coded regions positioned along the axis of the scalar element, each coded region of the series of coded regions disposed between two index lines of the series of index lines, wherein each coded region includes a pattern with a dimension along a direction perpendicular to the axis of motion, and wherein the variation of the pattern along the direction perpendicular to the axis of motion encodes information that represents a number designating an absolute position of the pattern along the axis of the scalar element;
a measuring device attached to the second object, the measuring device including a two-dimensional optical sensor array configured to capture an image of a portion of the scalar element, the image including a first pattern in one coded region of the series of coded regions; and
a processor configured to:
receive the image;
determine the absolute position of the first pattern along the axis of the scalar element based on the information encoded by the first pattern;
determine an offset between a center region of the image and the one coded region; and
determine an absolute position of the first object with respect to the second object based on at least one index line of the series of index lines, the absolute position of the first pattern, and the offset between the center region of the image and the one coded region of the series of coded regions.