Camera based touch system
First Claim
Patent Images
1. An apparatus for touch detection, comprising:
- (a) a touch panel characterized with X-Y coordinates;
(b) an imaging device associated with the touch panel and configured to acquire an image of the touch panel and transfer the acquired image into a signal array that is a function of an angle; and
(c) a processor in communication with the imaging device for receiving the signal array therefrom, comparing a peak signal of the signal array with a predefined threshold and if the peak signal is greater than the predefined threshold, obtaining the peak'"'"'s width, W, and angle, Θ
, relative to the touch panel so as to determine the location (X, Y) of a pointer in the touch panel in the forms of;
X=R×
cos(Θ
),
Y=R×
sin(Θ
),wherein R is a distance of the pointer and the imaging device, and satisfies the relationship of
W=A×
RB+C, wherein A, B and C are constant coefficients.
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Abstract
One aspect of the present invention relates to an apparatus for touch detection. In one embodiment, the apparatus includes a touch panel, an imaging device mounted to the touch panel and configured such that when a pointer touches the touch panel, the imaging device acquires an image of the pointer touching the touch panel, and a processor in communication with the imaging device for receiving and processing the acquired image to obtain its width and its angle relative to the touch panel so as to determine the location of the pointer in the touch panel.
23 Citations
38 Claims
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1. An apparatus for touch detection, comprising:
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(a) a touch panel characterized with X-Y coordinates; (b) an imaging device associated with the touch panel and configured to acquire an image of the touch panel and transfer the acquired image into a signal array that is a function of an angle; and (c) a processor in communication with the imaging device for receiving the signal array therefrom, comparing a peak signal of the signal array with a predefined threshold and if the peak signal is greater than the predefined threshold, obtaining the peak'"'"'s width, W, and angle, Θ
, relative to the touch panel so as to determine the location (X, Y) of a pointer in the touch panel in the forms of;
X=R×
cos(Θ
),
Y=R×
sin(Θ
),wherein R is a distance of the pointer and the imaging device, and satisfies the relationship of
W=A×
RB+C,wherein A, B and C are constant coefficients. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for optically detecting a touch location in a touch panel, comprising the steps of:
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(a) providing an imaging device associated with the touch panel; (b) acquiring an image of the touch panel; (c) transferring the acquired image into a signal array that is a function of an angle; (d) comparing a peak signal of the signal array with a predefined threshold; and (e) if the peak signal is not greater than the predefined threshold, repeating steps (b)-(d), otherwise, obtaining the peak'"'"'s width, W, and angle, Θ
, relative to the touch panel so as to determine the location (X, Y) of a pointer in the touch panel in the forms of;
X=R×
cos(Θ
),
Y=R×
sin(Θ
),wherein R is a distance of the pointer and the imaging device, and satisfies the relationship of
W=A×
RB+C,wherein A, B and C are constant coefficients. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. An apparatus for detecting touch locations of first and second pointers in a touch panel, comprising:
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(a) at least first and second imaging devices spatially mounted to the touch panel, each imaging device configured to acquire an image of the touch panel, and transfer the acquired image into a corresponding signal array that is a function of an angle; and (b) a processor in communication with each imaging device for receiving the corresponding signal arrays therefrom, comparing each peak signal of each signal array with a predefined threshold and if the peak signals are greater than the predefined threshold, obtaining the maximal widths, W1 and W2, and its corresponding angles, Θ
1 and Θ
2, of the signal arrays corresponding to the images captured by the first and second imaging devices, respectively, so as to determine touch locations (X1, Y1) and (X2, Y2) of first and second pointers, respectively, in the touch panel in the forms of;
X1=R1×
cos(Θ
1),
Y1=R1×
sin(Θ
1),
X2=D−
[R2×
cos(Θ
2)],
Y2=R2×
sin(Θ
2),wherein D is a distance between the first and second imaging devices, and wherein Rj is a distance between the j-th pointer and the j-th imaging device, j=1 and 2, and satisfies the relationship of
Wj=Aj×
RjBj+Cj,wherein Aj, Bj and Cj are constant coefficients. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29)
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30. A method for optically detecting one or more touch locations in a touch panel, comprising the steps of:
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(a) providing first and second imaging devices spatially mounted to the touch panel; (b) acquiring a first image and a second image of the touch panel by the first and second imaging devices, respectively; (c) transferring the acquired first image into a first signal array that is a function of an angle; (d) comparing each peak signal of the first signal array with a predefined threshold; (e) if the peak signal is greater than the predefined threshold, analyzing the peak number of the first signal array and obtaining the maximal width, Wj, and its corresponding angle, Θ
j;(f) determining the location (Xj, Yj) of the first pointer in the touch panel in the forms of;
Xj=Rj×
cos(Θ
j),
Yj=Rj×
sin(Θ
),wherein Rj is a distance of the j-th pointer and the j-th imaging device and satisfies the relationship of
Wj=Aj×
RjBj+Cj,wherein Aj, Bj and Cj are constant coefficients, wherein j=1; (g) reporting the touch position of the first pointer; and (h) repeating steps (c)-(g) for the acquired second image, wherein j=2. - View Dependent Claims (31, 32, 33, 34, 35, 36, 37, 38)
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Specification