| 摘要 |
A method for detecting the coordinates of multiple touching objects on an infrared touch screen without errors and a method for detecting the area of the touched spot are provided. The coordinate detection method includes measuring and storing the maximum received level of a pair of infrared emitting and receiving elements, emission and reception of which is not impeded by any object, and initializing an index variable for identification of multiple touched spots, determining that the screen has been touched when a received level of a pair of infrared emitting and receiving elements, emission and reception of which is impeded by an object, is less than the maximum level, measuring the minimum level to detect center coordinates of the object, and reading an index variable for the center coordinates and determining that the center coordinates are new and setting an index variable for the center coordinates if no index variable is read for the center coordinates and storing the center coordinates and the index variable for the center coordinates. The area detection method also includes measuring received levels of three pairs of infrared emitting and receiving elements corresponding to the center and two ends of the object and measuring and storing X and Y-axis diameters of a spot touched by the object based on the measured levels, and measuring the area of the touched spot based on the diameters under the assumption that the spot is an oval.
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