Object shape determination method and system therefor
First Claim
1. A method for determining the shape of an unknown object placed in an electrostatic sensing region extending from sensor apparatus comprising a plurality of electrostatic receiving means and at least one electrostatic transmission means, the method comprising:
- measuring the change in charge induced by said unknown object on each receiving means and storing said charge measurements as a first charge image dataset Cf,retrieving a predetermined shape dataset representing point co-ordinates which define said predetermined shape,determining for the first charge image dataset Cf a charge distribution dataset q′
representing the charge distribution required on the predetermined shape to substantially result in the measured charge image Cf,calculating the electrostatic potential distribution in the sensing region corresponding to said charge distribution dataset q′
,generating a new shape dataset having co-ordinates corresponding to points in the sensing region where the electrostatic potential distribution is close to zero, anddetermining the new shape dataset as representing the shape of the unknown object in the sensing region by comparing the difference between the new shape dataset and the predetermined shape dataset against a predetermined threshold.
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Abstract
An unknown object shape is computed using repeated iterations of electrostatic calculations on a predetermined shaped object and sensed electrostatic measurements. The predetermined object shape is morphed toward the unknown object shape at each iteration until the object shape is determined. The morphing of the shape is based on calculating the zero contour of the electrostatic potential, which potential depends on a charge distribution applied to the predetermined shape.
14 Citations
20 Claims
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1. A method for determining the shape of an unknown object placed in an electrostatic sensing region extending from sensor apparatus comprising a plurality of electrostatic receiving means and at least one electrostatic transmission means, the method comprising:
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measuring the change in charge induced by said unknown object on each receiving means and storing said charge measurements as a first charge image dataset Cf, retrieving a predetermined shape dataset representing point co-ordinates which define said predetermined shape, determining for the first charge image dataset Cf a charge distribution dataset q′
representing the charge distribution required on the predetermined shape to substantially result in the measured charge image Cf,calculating the electrostatic potential distribution in the sensing region corresponding to said charge distribution dataset q′
,generating a new shape dataset having co-ordinates corresponding to points in the sensing region where the electrostatic potential distribution is close to zero, and determining the new shape dataset as representing the shape of the unknown object in the sensing region by comparing the difference between the new shape dataset and the predetermined shape dataset against a predetermined threshold. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification