System and method for transforming an ordinary computer monitor into a touch screen
First Claim
1. A computer-implemented process for transforming a computer screen into a touch screen using a camera, comprising using a computer to perform the following process actions:
- inputting images of the computer screen;
computing a projective mapping between the images and the screen which is capable of determining the screen coordinates of a point in the images;
locating a tip of an indicator in said images, said indicator being superimposed on the screen in the image; and
determining the position of the tip of the indicator on the screen from the images of the screen using said projective mapping.
1 Assignment
0 Petitions
Accused Products
Abstract
A system and method for turning a regular computer monitor screen into a touch screen using an ordinary camera. It includes an image-screen mapping procedure to correct for the non-flatness of the computer screen. It also includes a segmentation method to distinguish the foreground, for example an indicator such as a finger, from the background of a computer screen. Additionally, this system and method includes a robust technique of finding the tip point location of the indicator (such as the finger tip). The screen coordinates of the tip point are then used to control the position of the system indicator.
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Citations
36 Claims
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1. A computer-implemented process for transforming a computer screen into a touch screen using a camera, comprising using a computer to perform the following process actions:
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inputting images of the computer screen;
computing a projective mapping between the images and the screen which is capable of determining the screen coordinates of a point in the images;
locating a tip of an indicator in said images, said indicator being superimposed on the screen in the image; and
determining the position of the tip of the indicator on the screen from the images of the screen using said projective mapping. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 12, 13, 14, 23, 30)
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10. Cancelled.
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11. Cancelled.
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15. A system for transforming a computer screen into a touch screen using a camera, the system comprising:
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a camera positioned so as to have an unobstructed view of the computer screen;
a general purpose computing device; and
a computer program comprising program modules executable by the computing device, wherein the computing device is directed by the program modules of the computer program to, input images of the computer screen from the camera;
compute a projective mapping between the images and the screen to determine the screen coordinates of a point in the images;
locate an indicator tip superimposed on the screen in the images; and
determine the position of the indicator on the screen from the images of the screen using said projective mapping. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 31)
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24. A computer-readable medium having computer-executable instructions for transforming a computer screen into a touch screen using a camera, said computer-executable instructions comprising:
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inputting images of the computer screen;
computing a homography which is capable of determining the screen coordinates of a point in the images, said homography being computed from at least four pairs of image-screen point correspondences;
locating a tip of an indicator in said images, said indicator being superimposed on the screen in the image; and
determining the position of the tip of the indicator on the screen from the images of the screen using said homography. - View Dependent Claims (25, 26, 27, 32)
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28. Cancelled.
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29. Cancelled.
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33. A system for transforming a computer screen into a touch screen, the system comprising:
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a camera positioned so as to have an view of a computer screen;
a general purpose computing device; and
a computer program comprising program modules executable by the computing device, wherein the computing device is directed by the program modules of the computer program to, establish a mapping between images taken by the camera of the indicator superimposed on the computer screen;
extract a background model from the images;
extract a foreground model of an indicator from the images;
locate the tip of the indicator in screen coordinates using said background and foreground models. - View Dependent Claims (34, 35)
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36. A process for transforming a computer screen into a touch screen, comprising the process actions of:
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positioning a camera so as to capture images of a computer screen with an indicator superimposed thereon;
establishing a mapping between the images and the screen;
locating a tip of an indicator in said images;
determining the position of the tip of the indicator on the screen from the images of the screen using said mapping; and
using said position of the tip of the indicator to control computer actions.
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Specification