Hybrid sensing techniques for position determination
First Claim
1. A method of determining the time-varying absolute position of device in respect to a surface, the method comprising the steps of:
- measuring at least one absolute position of the device in respect to the surface;
measuring a time-varying vector representing the movement of the device in respect to the surface; and
initialising the position of vector to the at least one absolute position measurement thereby measuring the absolute position of the vector and thus the time-varying absolute position of the device.
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Abstract
The invention provides for a method and apparatus for improving error-correction in non-contact optical position sensing. The primary application is in page-based data input contexts such as form-filling and paper-based web interfaces and GUIs. The invention utilises a combined measurement of the relative movement of a device in relation to a fixed surface and at least one measurement of the absolute position of the device. Absolute measurement of position is preferably carried out using a position-encoded glyph bed embedded on the fixed surface. Based on the at least single absolute measurement, the relative measurement of the devices movement, or stroke, is normalised to the properly measure absolute position and thus substantial interruptions in the detection of the absolute stroke position can be tolerated and corrected for.
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Citations
25 Claims
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1. A method of determining the time-varying absolute position of device in respect to a surface, the method comprising the steps of:
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measuring at least one absolute position of the device in respect to the surface;
measuring a time-varying vector representing the movement of the device in respect to the surface; and
initialising the position of vector to the at least one absolute position measurement thereby measuring the absolute position of the vector and thus the time-varying absolute position of the device. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 20, 21, 22, 24, 25)
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2. A method of determining the absolute position of a stroke made by a measurement device in respect to a surface, said surface having embedded thereon position encoding indicia, the method comprising the steps of:
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detecting one or more position encoding indicia and thereby calculating at least one absolute position measurement of the device;
in conjunction with the aforementioned step, measuring the relative movement of the device in respect to the surface and thereby calculating a time-varying motion vector representing the movement of the device in respect to the surface; and
calculating the absolute location of the stroke in respect to the surface on the basis of at least one measurement of the absolute position in combination with the time-varying motion vector.
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12. A measurement device for determining the time-varying absolute position of the device in respect to a surface including:
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a first measuring device arranged to determine at least one absolute position of the device in respect to the surface;
a second measuring device arranged to determine a time-varying vector representing the movement of the device in respect to the surface;
processing means adapted to initialise the position of vector to the at least one absolute position measurement and output a signal representing the absolute position of the vector and thus the time-varying absolute position of the device. - View Dependent Claims (14, 15, 16, 17, 18, 19)
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13. A measurement device for determining the absolute position of a stroke made by the measurement device in respect to a surface, said surface having embedded thereon position encoding indicia, the measurement device including:
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a first measuring device arranged to detect one or more position encoding indicia and determine at least one absolute position measurement of the device;
in conjunction with the aforementioned step, a second measuring device arranged to measure the relative movement of the device in respect to the surface and output a time-varying motion vector representing the movement of the device in respect to the surface; and
processing means adapted to calculate the absolute location of the stroke in respect to the surface on the basis of the at least one measurement of the absolute position in combination with the measurement of the time-varying motion vector.
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Specification