Hewlett-Packard Company

David Everett Reynolds

Richard Hull

Dipankar Gupta

Dominic Paul McCarthy

There is provided a lossy ink compression system aimed at low cost, high compression of ink on hand-held platforms. The present invention detects the critical cusp, or knot points in the ink and then resamples the smooth curves between successive cusp points discarding the dynamic information. The resampled data is then scaled to more closely match the display resolution. Finally, the data is delta coded and then packed for storage.

Method and apparatus for compression of electronic ink

The present invention relates to scribble matching methods, ie. methods for searching samples of electronic ink without having first to translate the ink into ASCII text. The methods of the present invention find application in pen-based computer devices. The invention entails the identification and encoding of velocity minima in the input scribble. Three scribble matching algorithms are described--a syntactic matcher, a word matcher and an elastic matcher. The syntactic matcher encodes the input scribble according to the shape of the scribble in the region of the velocity minima. The word matcher encodes the input scribble according to the heights of the velocity minima from a reference line, using a continuous height encoding scheme. The elastic matcher encodes the input scribble according to a classification of the velocity minima and intermediate points. The use of velocity minima in the encoding of scribble input provides a stable set of points and leads to improved performance in comparison with known scribble matching methods.

Scribble matching

A pen-based computer in which the lines drawn by a user are anti-aliased incrementally by applying a smoothing filter to the relatively high resolution pen sensor image and subsampling the result to provide a relatively low resolution image which is displayed using greyscale.

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Thornbury, United Kingdom

David Everett Reynolds