Method and apparatus for detecting a multitouch event in an optical touch-sensitive device
First Claim
1. A method for determining a touch point on a touch-sensitive optical device comprising a plurality of optical emitters and a plurality of optical detectors, the optical emitters and the optical detectors defining therebetween a plurality of optical beam paths forming an optical beam intersection pattern extending over an area, the method comprising the steps of:
- detecting a modulation of energy in beams transmitted along each of a pair of optical beam paths;
assigning a candidate touch point at an intersection of said pair of modulated beams;
selecting one or more other beams near to said candidate touch point;
determining that one or more of the other beams is uninterrupted;
eliminating the candidate touch point at the intersection from consideration as an actual touch point based on the determination that the one or more of the other beams is uninterrupted.
1 Assignment
0 Petitions
Accused Products
Abstract
A touch sensitive optical control device comprising a set of light emitters 14, 22 and light detectors 18, 24 arranged relative to a touchable surface 30 such that light transmitted by the emitters is received by the detectors along multiple intersecting beams which pass transversely of the surface and touching the surface at a beam interrupts the light transmitted along the beam. Candidate touch points T1, T2, F1, F2 are defined at the intersections of interrupted beams and are confirmed or not as actual touch points by examining test beams 40, 42, 54, 56 near to or coincident with the candidate touch point.
47 Citations
23 Claims
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1. A method for determining a touch point on a touch-sensitive optical device comprising a plurality of optical emitters and a plurality of optical detectors, the optical emitters and the optical detectors defining therebetween a plurality of optical beam paths forming an optical beam intersection pattern extending over an area, the method comprising the steps of:
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detecting a modulation of energy in beams transmitted along each of a pair of optical beam paths; assigning a candidate touch point at an intersection of said pair of modulated beams; selecting one or more other beams near to said candidate touch point; determining that one or more of the other beams is uninterrupted; eliminating the candidate touch point at the intersection from consideration as an actual touch point based on the determination that the one or more of the other beams is uninterrupted. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. The method as claimed claim in 16, wherein normalizing further comprises dividing said point validity value by the number of predetermined other beams.
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19. A touch-sensitive optical device comprising a plurality of optical emitters and a plurality of optical detectors, the optical emitters and the optical detectors arranged relative to a touchable surface such that energy transmitted by the emitters is received by the detectors along multiple intersecting beams which pass adjacent the surface, and wherein touching the surface at a beam causes a detectable modulation of the energy transmitted along the beam, the device further comprising a processing means operable to perform the following steps:
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detecting a modulation of energy in beams transmitted along each of a pair of optical beam paths; assigning a candidate touch point at an intersection of said pair of modulated beams; selecting one or more other beams near to said candidate touch point; determining that one or more of the other beams is uninterrupted; eliminating the candidate touch point at the intersection from consideration as an actual touch point based on the determination that the one or more of the other beams is uninterrupted. - View Dependent Claims (20, 21, 22, 23)
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Specification