	US 7,518,738 B2
	Method and a device for optically detecting the position of an object by measuring light reflected by that object
Gilles Cavallucci, Nimes (France); Julien P. Sylvestre, Nimes (France); and Philippe G. Plantier, Nimes (France)
Assigned to H2I Technologies, Nimes (France)
Appl. No. 10/540,579 PCT Filed Sep. 02, 2004, PCT No. PCT/FR2004/002245 § 371(c)(1), (2), (4) Date Jun. 24, 2005, PCT Pub. No. WO2005/024621, PCT Pub. Date Mar. 17, 2005.
Claims priority of application No. 03 10378 (FR), filed on Sep. 02, 2003.
Prior Publication US 2006/0152740 A1, Jul. 13, 2006
Int. Cl. G01B 11/14 (2006.01)

U.S. Cl. 356—614

39 Claims

1. An optical detection method of determining the position of an object in a particular detection area of a surface, the method comprising:

a preliminary step of disposing in the vicinity of said detection area and on the same side thereof relative to the object at least four elements including two emitters of light and at least two receivers of light adapted to cover the detection area, each emitter being adapted to emit light in such a way that it does not hit said surface in the detection area, said emitters and receivers being disposed in an alternating and regular arrangement, the method further comprises:

a step during which one of said receiver measures the quantity of light reflected by the object when the object is illuminated by one of said emitters for at least two different emitter—receiver pairs,

a step of calculating at least two characteristic values from said measured values, wherein, as emitters and receivers are disposed in the alternating and regular arrangement, a characteristic value is calculated for each emitter by averaging the values measured by the receivers on each side of said emitter when only said emitter is turned on, and

a step of determining at least one position of the object by directly reading a table indexed by said at least two characteristic values, the content of said table being predetermined and set before said measurement step.