Summagraphics Corporation

Calcomp Technology, Inc.

Robert M McDermott

Paul D Smith

Thomas C Zalenski

Scott D McDermott

Michael J Padula

Daniel G Lasley

Michael Bals

Anthony M Scialdone

This invention provides apparatus and a method which self-adjust the pressure response of a digitizer pointing device or other device incorporating a pressure transducer according to the characteristics of the particular device and/or particular user of the device. For example, a digitizer user when inputting with a stylus pointing device may use different writing styles in simulated paint brush and in simulated chalk, or, the user may use the stylus device entirely differently when using it in a game or in a graphic arts application, or different users may use the same stylus device differently for the same application. Certain pressure parameters of the device are not set on a fixed basis, which would provide for an average, typical or generic pressure range and resolution. Instead, the particular user's use of the device is monitored, and the pressure range and/or sensitivity of the device are automatically, or semi-automatically adjusted to provide a suitable pressure range and maximum resolution for the particular user.

Dynamic pressure adjustment of a pressure-sensitive pointing device for

In a digitizer and method for laying out and using the tablet of the digitizer, wherein the tablet provides unambiguous binary code outputs. The digitizer may employe a cordless transducer and signal processing circuitry providing relative phase detection for determining coarse location of the transducer. An unambiguous binary code output is obtained with a grid layout which generates a set of unique binary codes, none of which is the the same or the binary inverse of any other member of the set.

Digitizer tablet using relative phase detection

A digitizer tablet providing hysteresis compensation in which the X and Y coordinates of a pointing device are measured at different times. In order to enable the tablet to report X and Y coordinates that when displayed will more accurately reflect the pointing device movements, a correction algorithm, built, for example, into the controlling software, estimates and reports what the first measured coordinate would have been, measured when the second coordinate is measured, based upon the calculated velocity and acceleration of the pointing device. A similar technique can be used to correct the reported value of the second coordinate. In a preferred embodiment, constant coefficients of a linear equation having as variables three consecutive coordinate values or three consecutive preprocessed coordinate values are predetermined and used in the correction algorithm. The preferred embodiment integrates the velocity and acceleration hysteresis compensation into a three point recursive noise filter.

Hysteresis compensation for a digitizer tablet

Disclosed herein are position determining apparatus and conductor structures or grids therefor. The conductor structure for each axis includes a number of conductors which are run in a serpentine-type path each with uniform repeat increment. The repeat increment, which is the spacing or span between one run and the next of the same serpentine-type conductor, are uniform for each conductor (but may change from conductor to conductor) and is constrained by a maximum repeat increment, or a minimum repeat increment. In the preferred embodiments, there is at least a constraint on the maximum repeat increment to provide noise immunity. The conductors are arranged for each axis of the grid in a pattern such that signals obtained for that axis may be processed to provide binary numbers in a Gray-type code each unique to a small region of the active area in which the coil center is located. The small region for a given axis corresponds to the space between two immediately adjacent, active conductor portions for that axis, with a possible ambiguity of one space. Small regions in each axis define the coarse location of the coil center. Fine location within a region may be determined from the magnitudes of currents induced in selected runs preferably by interpolation.

Digitizer with serpentine-type conductor grid having uniform conductor

A digitizer table which employs low pass filtering of raw coordinate data to reduce noise and jitter. A weighted filtering is employed, in which the new position data is averaged with a previous average or previous position data before being reported. The weighting factor applied to the new data is determined by the degree of monotonicity represented by the data, with intentional movements of the pointing device indicating high monotonicity undergoing light filtering but noise indicating low monotonicity undergoing heavy filtering.

Dynamic adjustment of filter weights for digital tablets

A digitizer tablet exhibiting improved regional error correction comprises evaluation of two linear equations to correct the generated raw coordinates. The equations contain certain constants unique to tablet regions exhibiting similar error patterns. These constants are empirically determined and stored for use in the evaluations.

Digitizer tablet with regional error correction

A digitizer tablet and puck(cursor) for use therewith, characterized that in one aspect the puck is provided with at least one additional control which will provide the user with the ability to control at least one N-dimensional signal in addition to the normal X-Y coordinate data. In accordance with another aspect, any pointing device for the tablet is provided with the capability to control the manner in which the N-dimensional signal varies in response to user manipulation of the pointing device.

Graphics tablet with N-dimensional capability

Disclosed herein are position determining apparatus and conductor structures or grids therefor. The conductor structure for each axis includes a number of conductors, at least one of which is run in a serpentine path with a non-uniform repeat increment. The repeat increment, which is the spacing between one run and the next of the same serpentine conductor, is constrained by a maximum repeat increment, or a minimum repeat increment, or a maximum change in repeat increments between consecutive runs of a same conductor, or combinations thereof. In the preferred embodiments, there is at least a constraint on the maximum repeat increment to provide noise immunity. The conductors are arranged for each axis of the grid in a pattern such that signals obtained for that axis may be processed to provide binary members in a Gray-type code each unique to a small region of the active area in which the coil center is located. The small region for a given axis corresponds to the space between two immediately adjacent, active conductor portions for that axis, with a possible ambiguity of one space. Smal regions in each axis define the coarse location of the coil center. Fine location within a region may be determined from the magnitudes of currents induced in selected runs by interpolation, or from the phase relationship of current induced in selected runs.

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Weston, CT, United States of America

Robert M McDermott