Patent ID: 7342572
Filing Date: 2008-03-11
Classification: G06F

Abstract:
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 taken by a camera positioned so as to have a frontal view 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, wherein the process action of locating the tip of the indicator in the inputted images, comprises the actions of: inputting an image of the computer screen lacking a depiction of an indicator pointed at the screen; extracting a model of the screen, referred to as a background model, from the input image lacking the depiction of the indicator, said background model being indicative of the screen when no indicator is pointed at it; inputting a second image of the screen which depicts an indicator pointed at the screen; extracting a model of the indicator, referred to as a foreground model, from the second image; inputting one or more subsequently-captured images of the screen; and for each subsequently-captured image,