Abstract: A watermark is encoded redundantly so as to provide effective copy protection. To assure a reliable detection of the watermark in the presence of a potentially faulty watermark detection process, some or all of the watermark is redundantly encoded. The number of redundant encodings of the watermark is selected so that upon modification of the watermarked material, sufficient redundancy exists so that the material can be identified as watermarked material, and the number of detected copies of the watermark is used to detect the modification. Statistical processes are employed to determine the presence or absence of the watermarks in the presence of a potentially faulty watermark detection process.

Abstract: A number of data items are selected for inclusion in a data set so as to discourage a transmission of the entire set over a limited bandwidth communications path, such as the Internet. The data set includes an entirety parameter that is used to determine whether the entirety of the data set is present. In a preferred embodiment, the entirety parameter is a hash value that is based on watermarks of each data item. When presented for rendering, the watermarks of the data items in the presented material are read and a hash value based on the presented watermarks is computed. A mis-match between the computed hash value and the entirety hash value contained in the data set indicates that less than the entirety of the data set is being presented, and the rendering is prohibited.

Abstract: A watermark is encoded redundantly so as to provide effective copy protection. To assure a reliable detection of the watermark in the presence of a potentially faulty watermark detection process, some or all of the watermark is redundantly encoded. The number of redundant encodings of the watermark is selected so that upon modification of the watermarked material, sufficient redundancy exists so that the material can be identified as watermarked material, and the number of detected copies of the watermark is used to detect the modification. Statistical processes are employed to determine the presence or absence of the watermarks in the presence of a potentially faulty watermark detection process.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.