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1. (WO2010112082) A ONE-DIMENSION POSITION ENCODER

Pub. No.:    WO/2010/112082    International Application No.:    PCT/EP2009/054021
Publication Date: Fri Oct 08 01:59:59 CEST 2010 International Filing Date: Sat Apr 04 01:59:59 CEST 2009
IPC: G01D 5/244
G01D 5/249
G01D 5/347
H03M 1/28
Applicants: CSEM CENTRE SUISSE D'ELECTRONIQUE ET DE MICROTECHNIQUE SA RECHERCHE ET DEVELOPPEMENT
HASLER, David
MASA, Peter
HEIM, Pascal
FRANZI, Edoardo
Inventors: HASLER, David
MASA, Peter
HEIM, Pascal
FRANZI, Edoardo
Title: A ONE-DIMENSION POSITION ENCODER
Abstract:
The present invention discloses a one-dimension position measurement system comprising: a first ruler, on which a first one-dimension binary code si is applied, a camera for acquiring a picture of a portion of said code si, said portion having a length of I bits, and some processing means. Each codeword of length I of the one-dimension code si is unique within the whole code si. A codeword ai is read from said acquired picture of said portion of code si, and the processing means are implemented for computing an absolute position p of said codeword ai of said code si from: (I). An ad-hoc interpolation method is used to obtain a precision way below the distance between two bits of the codewords. The code si may be applied on the ruler by using some geometric primitives, a geometric primitive for encoding a "1" being different from a geometric primitive for encoding a "0", both having the same horizontal projection. The horizontal projection is then used for fine interpolation, achieving nanometre-scale resolution.