Marking system with pen-up/pen-down tracking
First Claim
1. In a graphic data-acquisition system for tracking the position of an implement relative to a writing surface, a sub-system for distinguishing between a write mode and a non-write mode of the writing implement comprisingelectromagnetic-radiation-generating structure disposed adjacent the writing surface and operable to produce an expanse of radiation in a substantially planar zone near the writing surface,radiation-interactive structure associated with the implement and capable of interacting with the expanse to produce signals which vary depending on a relative distance between a writing tip on the implement and the writing surface,monitoring structure capable of detecting and converting the signals into an analog data stream, anda processor for receiving and processing the data stream to determine when the implement is in the write mode and when the implement is in the non-write mode.
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Accused Products
Abstract
A system and method for detecting movement of an object along an axis normal to a planar surface is described. The invention is applied to a graphic data-acquisition system in which a digitized record is produced according to the X, Y and Z location of a writing implement relative to a writing surface. An expanse of electromagnetic radiation is generated in a zone closely adjacent to the writing surface. An electromagnetic-interactive structure is associated with the writing implement at a location where it will interact with the expanse when the pen is in a write mode. The configuration of the radiation-interactive structure and its positioning relative to the expanse allows the production of an analog data stream which may be correlated to relative distance between the tip of the pen and the writing surface. After fine analog data is digitized, a processing routine is used to determine reliably and accurately when the pen has moved to the non-write mode. The processor is configured to perform the desired discriminatory function with minimal occurrences of false positives relating to pen tilting, writing velocity and board irregularity.
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Citations
13 Claims
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1. In a graphic data-acquisition system for tracking the position of an implement relative to a writing surface, a sub-system for distinguishing between a write mode and a non-write mode of the writing implement comprising
electromagnetic-radiation-generating structure disposed adjacent the writing surface and operable to produce an expanse of radiation in a substantially planar zone near the writing surface, radiation-interactive structure associated with the implement and capable of interacting with the expanse to produce signals which vary depending on a relative distance between a writing tip on the implement and the writing surface, monitoring structure capable of detecting and converting the signals into an analog data stream, and a processor for receiving and processing the data stream to determine when the implement is in the write mode and when the implement is in the non-write mode.
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12. In a graphic data-acquisition system for tracking the position of a writing implement relative to a writing surface by producing and interpreting an analog data stream from interaction between an expanse of electromagnetic radiation and the writing implement, a method of determining when the implement is in a write mode and when the implement is in a non-write mode comprising
connecting a radiation-interactive structure to the implement so that the structure interacts with the expanse when the implement is in the write mode, producing an analog signal from varying interaction between the structure and the expanse as the implement is moved in a pen-up/pen-down direction generally perpendicular to the writing surface, and interpreting the signal to determine when the implement moves between the write mode and non-write mode.
Specification