Image analysis – Pattern recognition – On-line recognition of handwritten characters
Reexamination Certificate
1998-08-31
2002-06-18
Couso, Jose L. (Department: 2721)
Image analysis
Pattern recognition
On-line recognition of handwritten characters
C382S188000, C382S314000, C345S158000, C345S169000, C345S179000, C707S793000
Reexamination Certificate
active
06408092
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to digital electronic systems that receive and use handwritten input in the nature of text.
Handwritten computer input has traditionally been captured using a stylus and a graphics tablet. Graphics tablets have a flat surface on which a user makes marks with the stylus that become electronic signals representing the successive positions of the stylus on the active area of the tablet. Many tablets, such as the graphics tablet products available from Wacom Technology Corporation of Vancouver, Wash., are pressure sensitive and provide pressure data along with position data. The Wacom tablets include tablets ranging in size from 4×5 to 18×25 (inches) and provide 256 levels (that is, eight bits) of pressure sensitivity. Other vendors provide larger and smaller tablets as well as tablets of different pressure sensitivity. Such tablets are generally connected to a personal computer to provide a superset of the functionality available with a mouse. In this configuration, position and pressure data are transmitted to an operating system or application program that ultimately generates display data on a display screen in response to gestures the user makes with the stylus on the tablet.
An input tablet can also be integrated with a display device, such as a liquid crystal display device. Such display tablets are well known from their use in personal digital assistant (PDA) devices such as the PalmPilot™ and Palm III™ organizers available from 3Com Corporation of Santa Clara, Calif. The input tablets on these devices are characteristically small, having an active area with a width on the order of two to two and one-half inches in the direction in which the user generally writes.
An input tablet can also be integrated with a keyboard or notebook computer, or added to a computer as a separate device, as a substitute for a mouse or other pointing device. In some products, such input tablets are also pressure sensitive.
With some input devices and software, marks made on a tablet can be erased or edited after they are made. The Wacom Erasing DuoSwitch® UltraPen® stylus, for example, has an eraser end that can be recognized as an eraser by device driver software and application software. Input tablets that are used as substitutes for a mouse generally support click and double-click functions. PDA devices generally support editing functions that can be invoked by gestures made by the user on the device's display tablet, either in the form of editing marks drawn on the tablet or in the form of gestures that select editing buttons.
SUMMARY OF THE INVENTION
Handwritten input in the nature of text is generally written in lines of script or characters, either horizontally or vertically, and either left-to-right or right-to-left. The length of a handwritten input can easily exceed the writing width available on an input tablet. The invention provides methods and apparatus that allow a person using an input tablet—in particular, a small tablet of the kind often found on a PDA device or a notebook computer—to write and edit arbitrarily long text in a restricted area.
In general, in one aspect, the invention features methods and apparatus implementing a technique for processing handwritten marks made on a machine-readable tablet. The technique includes providing multiple regions for input on the tablet; receiving from a user handwritten marks made in a current region of the plurality of regions; receiving from the user an indication that the current region is complete and thereupon selecting a different one of the plurality of regions as the current region in which to receive handwritten marks made by the user, whereby marks are received in a sequence of at least two regions; and representing the handwritten input as the aggregate of the marks written in the sequence of regions in a writing direction, the marks in different input regions having positions with respect to each other defined by a logical concatenation of the regions on the sequence of regions. The input can be arbitrarily-long markings of any kind.
Advantageous implementations of the invention include one or more of the following features. A bounding box is defined for each input region and the bounding boxes are logically concatenated to define the positions of the marks in different input regions with respect to each other. Each bounding box has a length in the writing direction, which length is defined dynamically to fit the marks made in the region. Each bounding box has a width perpendicular to the writing direction, which width is the same for all bounding boxes. The bounding box for each input region has a leading boundary the position of which is fixed with respect to the input region and a trailing boundary the position of which varies with respect to the input region to accommodate the marks made in the input region. The input regions and the sequence of input regions have a writing direction but no other predefined structure with respect to the marks to be made within the input regions. The logical concatenation of regions includes logically concatenating a trailing edge of one region to a leading edge of an immediately subsequent region. The writing direction is horizontal or vertical.
Handwritten marks can be received at any place and in any arbitrary order within the current region. Handwritten marks are displayed substantially simultaneously with the making of the marks. Handwritten marks are stored as mark data in a memory operatively coupled to the tablet, and the stored mark data is combined to form the representation of the handwritten input. The mark data represents the marks made by the user as set of times and positions of a stylus on the tablet. Both a recently-written portion of the handwritten marks as made by the user and the marks made by the user in the current region are displayed while marks are being made in the current region. The tablet is a display tablet having an integrated display device. The recently-written portion of the handwritten marks as made by the user is displayed at a reduced size in a reviewing area on the display device. Unmarked space is logically trimmed from one end but not from the opposite end of each of the regions before logically concatenating the one end of the region with a sequentially neighboring region. The plurality of regions consists of two regions, and the user indicates that the current one of the two regions is complete by making a mark in the other one of the two regions. The display of the current region is cleared after the user indicates that the current region is complete. Handwritten marks can include editing marks such as marks denoting a modification of marks previously made in the current region. The modification can be erasure. The handwritten input can be a signature. The tablet has an active area with a length of less than about two and one-half inches in a writing direction. The marks written in each region in the sequence of regions are combined in an output stream as a chunk of data. This output stream includes a sequence of chunks, and the locations of bounding box boundaries are specified in the output stream. The handwritten input is displayed in lines that break at input region boundaries. The marks are received in a first region and a second region alternately and concatenated logically to an output stream. The mark data in the output stream are displayed by reflowing the mark data in units of chunks in a display area. The display area is a rectangular area defined within an electronic document. The sequence of chunks can be edited by deleting a chunk, by inserting a chunk, by replacing a chunk, by modifying a chunk, or by rearranging chunks.
Advantages that may be seen in implementations of the invention include one or more of the following. The invention allows a person to write and edit text comfortably and reliably, even when the input area is restricted. The invention allows a person to enter a signature comfortably in a restricted area. The use of input regions imposes n
Adobe Systems Incorporated
Couso Jose L.
Desire Gregory
Fish & Richardson P.C.
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