Diffusion-assisted position location particularly for visual pen detection
First Claim
1. A system for optically determining the direction of an object, said system comprising:
- a photodetector having a plurality of detector elements extending in at least one dimension;
elements for projecting a diffuse image of the object onto said photodetector such that each of said detector elements produces an output signal corresponding to the intensity of that portion of the diffuse image which is projected onto the particular detector element, the diffuse image having a characteristic intensity distribution; and
a data analyzer connected for receiving the output signals from said detector elements and operable to locate the position of the diffuse image on said photodetector by recognizing the characteristic intensity distribution of the diffuse image.
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Accused Products
Abstract
Systems and methods for optically determining the direction of an object, such as a pointer, relative to an imaging system, particularly systems where triangulation is employed to determine the location of a pointer within a generally planar viewing field, such as a touch screen. Rather than employing focused imaging systems to produce a sharp image at the plane of a photodetector, and to thus define the visual pen for finger position, a deliberately diffuse or blurred image is employed. The diffusion produces a characteristic "bell-shaped" or Gaussian intensity distribution. By recognizing the characteristic intensity distribution, the position of the maximum intensity, and thus the direction of the object, can be determined to a small fraction of the distance between sample points, with an accordingly much higher resolution than focused systems. In a preferred embodiment, the position location system is incorporated into a computer system as a touch screen apparatus and a cursor is displayed on the screen as soon as a pointer is detected above the display.
459 Citations
40 Claims
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1. A system for optically determining the direction of an object, said system comprising:
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a photodetector having a plurality of detector elements extending in at least one dimension; elements for projecting a diffuse image of the object onto said photodetector such that each of said detector elements produces an output signal corresponding to the intensity of that portion of the diffuse image which is projected onto the particular detector element, the diffuse image having a characteristic intensity distribution; and a data analyzer connected for receiving the output signals from said detector elements and operable to locate the position of the diffuse image on said photodetector by recognizing the characteristic intensity distribution of the diffuse image. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method for optically determining the direction of an object, said method comprising:
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projecting a diffuse image of the object onto a photodetector having a plurality of detector elements extending in at least one dimension such that each of the detector elements produces an output signal corresponding to the intensity of that portion of the diffuse image which is projected onto the particular detector element, the diffuse image having a characteristic intensity distribution; locating the position of the diffuse image on the photodetector by recognizing the characteristic intensity distribution of the diffuse image. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A system for optically determining the position of an object within a generally planar viewing field, said system comprising:
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at least a pair of detector systems in the same plane as the viewing field and arranged to view the object within the viewing field from different angular positions, each of said detector systems including a photodetector having a plurality of detector elements extending in at least one dimension, and elements for projecting a diffuse image of the object onto said photodetector such that each of said detector elements produces an output signal corresponding to the intensity of that portion of the diffuse image which is projected onto the particular detector element, the diffuse image having a characteristic intensity distribution; a data analyzer connected for receiving the output signals from said detector elements, and operable to locate the position of the diffuse image on each of said photodetectors by recognizing the characteristic intensity distribution of the diffuse image and thereby to determine the direction of the object relative to each of said detector systems, and to determine the position of the object by triangulation based on the determined directions. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37)
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38. A system for determining the position of an object adjacent to a surface of a display having a perimeter, said system comprising:
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at least a pair of detector systems positioned outside of and adjacent to the perimeter of the display and arranged to view the object from different angular positions and to view the object when it is positioned on the surface of the display and when the object is positioned adjacent to the surface of the display, but spaced apart from the display, each of said imaging systems including a photodetector and elements for projecting a light pattern corresponding to the object onto said photodetector such that said photodetector produces output signals corresponding t the intensity distribution of the light pattern; and a data analyzer connected for receiving the output signals and operable to locate the position of the light pattern on each of said photodetectors and thereby to determine the direction of the object relative to each of said imaging systems, to determine the position of the object by triangulation based on the determined directions, and to display a cursor on the display at a position corresponding to the position of the object, said cursor being displayed when the object is adjacent to, but spaced apart from, the display. - View Dependent Claims (39, 40)
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Specification