Abstract:
A system and method for changing data displayed on a touch-sensitive display screen. The present system and method recognize handwritten strokes made with a stylus on the touch-sensitive display screen of a PDA or palmtop computer in order to alter or correct displayed data. In one mode of operation, computer controlled association of the location of the handwritten strokes on the display screen with one or more of the displayed characters will result in automatic replacement of those characters by the handwritten strokes. In a second mode of operation, matching at least one of the handwritten strokes with one character of the displayed data will result in replacement of one or more characters of the displayed data with the handwritten characters. With the present system and method, the number of steps required to alter displayed data is reduced to the number of handwritten strokes. A significant reduction in time and effort as well as a simplification in application is therefore offered.

Description:
This is a continuation of application(s) Ser. No. 09/873,006 filed on May 31, 2001 now U.S. Pat. No. 6,690,364 which is hereby incorporated by reference to this specification. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to the field of portable devices such as personal digital assistants or palmtop computer systems. More specifically, embodiments of the present invention relate to the recognition and correction of displayed text. 
   2. Related Art 
   As the components required to build a computer system have reduced in size, new categories of electronic devices and computer systems have emerged. One of the new categories of computer systems is the “palmtop” computer system. A palmtop computer system is a computer that is small enough to be held in the hand of a user and can therefore be “palm-sized.” Most palmtop computer systems are used to implement various Personal Information Management (PIM) applications such as an address book, a daily organizer (calendar, date book, etc.) and electronic notepads, to name a few. Palmtop computers with PIM software have been known as Personal Digital Assistants (PDAs). Many PDAs have a small and flat display screen associated therewith. 
   User convenience and device value are very important factors for portable electronic devices. Typically, portable electronic devices are employed while the user is on the run, e.g., in business meetings, on business travel, personal travel, in a vehicle, on foot, etc. Because the user may be occupied or busy while using the portable electronic device, the number of user steps or user tasks required in order to access information from an electronic device (or to store information into the electronic device) is crucial for producing a commercially successful and useful product. That is, the more difficult it is to access data from an electronic device, the less likely the user will perform those tasks to obtain the information. Likewise, the easier information is to obtain, the more likely the portable electronic device will be used to obtain that information and the more likely the portable electronic device will become a part of the user&#39;s everyday activities. 
   Similarly, the more difficult it is to enter data into an electronic device, the less likely the user will perform those tasks required to communicate information. The easier it is to input information, the more likely the portable electronic device will be used to communicate that information and the more likely the portable electronic device will become a part of the user&#39;s everyday activities. A stylus is frequently utilized in an on-screen handwriting system to enter data into a PDA. An important aspect of this operation is the ease with which the user can alter or correct such written information. The current state of the art is to move a visual selection tool or cursor around the screen and edit via the same mechanism that was used to enter the original text or data, however, extra strokes or entry actions are required to perform character deletions, etc. 
   The ability to modify information displayed on a touch-sensitive display screen, such as spelling errors or perhaps inaccurate numerical data, is an important function. Since the characters used to display information on the screen are relatively small, the spacing between characters is also quite small. This adds to the difficulty of locating, identifying and correcting a single character or groups of characters displayed on a display screen. One conventional method for allowing a user to correct mistakes requires that entire words be corrected at once. In effect, the user is required to identify a larger segment of information (for example a complete word) that is then displayed in magnified form for correction on the screen. However, there are many instances were only one character may be mistaken in a large word. It is very inconvenient to require a user to re-enter an entire word if just one character is mistaken. 
   Other correction techniques require that the user position a visual correction tool, e.g., a cursor, near the character to be corrected. The difficulty with the conventional correction methods involves the amount of time and effort required. For instance, to correct one mistake may require three to four separate actions, often in three disparate areas of the screen or device. For example, the user needs to position the cursor, perform a delete, reenter the new character, and then reposition at a last location. Therefore, existing systems and methods for accomplishing text correction are generally multiple step operations, and they generally are limited to altering only one character at a time. What is needed is a mechanism and method for allowing a user to easily make corrections with respect to displayed text without requiring the number of steps required of the cursor approach described above. 
   SUMMARY OF THE INVENTION 
   Accordingly, what is needed is a more generally applicable method or system that provides for more user friendly on-screen alterations or corrections of displayed information. What is also needed is a method or system that will allow operation on one or more characters, as well as replacement of portions of displayed information, in terms of the location of the information on the display screen. In addition, what is needed is a method or system that will function properly in response to handwritten strokes made on a touch screen by a user. What is also needed is a method or system that simplifies the alteration or correction process by reducing the number of steps required in existing methods and systems. 
   Just as one would make a voice correction by back tracking and repeating some of the correct information to provide context for where to place a correction, embodiments of the present invention use location and repetition of context to allow in-place correction of text on-screen without changing the input state of the device by persistently moving the cursor or creating selections of text (both of which are error prone due to the accuracy of pen placements required). 
   This correction recognizer is capable of using any handwriting system the user employs. The user simply rewrites the text to be corrected at the approximate on-screen location where the correction should take place. A user may have to repeat one or more correct characters to make the correction unique. The system then compares the new handwriting against the existing text to locate a match between them for at least one or more characters. 
   Audible feedback may be incorporated so the user will know when this match is found. A heuristic of placing the new text at the location where the best match is found is used. For instance, if you write “our right” and you need to correct it to “you&#39;re right” then writing (&#39;re) may not be enough since there are two r&#39;s near each other. Writing (&#39;re) (with a space) would be enough, or (u&#39;re) would work. This allows the user to naturally correct just as they are used to when spelling words or numbers out vocally. A cursor or other correction tool is not required to make the correction. 
   A system and method for changing data displayed on a touch-sensitive display screen are described. The ability to modify information displayed on a touch-sensitive display screen, such as spelling errors or perhaps inaccurate numerical data, is an important function. Existing systems and methods for accomplishing this function are generally multiple step operations, and they generally are limited to altering only one character at a time. The present system and method recognize handwritten strokes made with a stylus on the touch-sensitive display screen of a PDA or palmtop computer in order to alter or correct displayed data. The present system and method is equally applicable with a display system in which a cursor is used to write handwritten strokes. 
   In one mode of operation, associating the location of the handwritten strokes on the display screen with one or more of the displayed characters will result in replacement of those characters by the handwritten (correction) strokes. In a second mode of operation, matching at least one of the handwritten strokes with one character of the displayed data will result in replacement of one or more characters of the displayed data with the handwritten characters. With the present system and method, the number of steps required to alter displayed data is reduced to the number of handwritten strokes. A significant reduction in time and effort as well as a simplification in application is therefore offered. 
   In one embodiment of the present invention, a portion of text to be modified is displayed on a touch-sensitive display screen. The input cursor is located at the end of the field of text. A stylus is used to handwrite a substitute character on the touch-sensitive display screen as the replacement for an existing character in the displayed text. Locating a portion of the handwritten stroke near an existing character on the display screen causes the system to examine this existing text nearby to identify the character to be replaced. Once a match is found between the correction text and the existing text, the substitute character is then automatically inserted in place of the existing character. It is possible to input more than one handwritten stroke at a time, thus allowing for simultaneous replacement of multiple characters. 
   In a second embodiment of the present invention, a portion of text to be modified is displayed on a touch-sensitive display screen. The input cursor is located at the end of the field of text. A stylus is used to handwrite one or more substitute characters on the touch-sensitive display screen as the replacement for a portion of the displayed text. It is appreciated that the replacement characters may be written in electronic ink over the text that is to be corrected. Locating one handwritten character in the vicinity of a similar existing character on the display screen identifies the position at which the replacement characters are to be inserted. Upon finding a match between a replacement character and an existing character, the substitute characters are automatically inserted in place of the existing characters with the matching characters occupying a similar location. The present system thus allows for replacement of portions of text composed of multiple characters. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1A  is a block diagram of an exemplary network environment including a portable computer system. 
       FIG. 1B  is a block diagram showing another embodiment for coupling a portable computer system to other computer systems and to the Internet. 
       FIG. 2  is a topside perspective view of an exemplary portable computer system. 
       FIG. 3  is a bottom side perspective view of the exemplary portable computer system of  FIG. 2 . 
       FIG. 4  is a block diagram of one embodiment of the exemplary portable computer system. 
       FIG. 5  is a perspective view of the cradle device for connecting the exemplary portable computer system to other systems via a communication interface in accordance with one embodiment of the present invention. 
       FIG. 6A  illustrates errors in text displayed on a touch-sensitive display screen according to an embodiment of the present invention. 
       FIG. 6B  illustrates text as displayed on a touch-sensitive display screen in  FIG. 6A  in which errors have been corrected according to an embodiment of the present invention. 
       FIG. 7  illustrates the placement of letters formed by handwritten strokes to be inserted in place of incorrect letters in existing text displayed on a touch-sensitive display screen according to an embodiment of the present invention. 
       FIG. 8  illustrates the placement of letters formed by handwritten strokes to be inserted in place of incorrect letters in existing text displayed on a touch-sensitive display screen according to an embodiment of the present invention. 
       FIG. 9  is a flowchart showing steps in a process for modifying data displayed on a touch-sensitive display screen according to an embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   In the following detailed description of the present invention, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be recognized by one skilled in the art that the present invention may be practiced without these specific details or with equivalents thereof. In other instances, well known methods, procedures, components, and circuits have not been described in detail as not to unnecessarily obscure aspects of the present invention. 
   Notation and Nomenclature 
   Some portions of the detailed descriptions, which follow, are presented in terms of procedures, steps, logic blocks, processing, and other symbolic representations of operations on data bits that can be performed on computer memory. These descriptions and representations are the means used by those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art. A procedure, computer executed step, logic block, process, etc., is here, and generally, conceived to be a self-consistent sequence of steps or instructions leading to a desired result. The steps are those requiring physical manipulations of physical quantities. Usually, though not necessarily, these quantities take the form of electrical or magnetic signals capable of being stored, transferred, combined, compared, and otherwise manipulated in a computer system. It has proven convenient at times, principally for reasons of common usage, to refer to these signals as bits, values, elements, symbols, characters, terms, numbers, or the like. 
   It should be borne in mind, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. Unless specifically stated otherwise as apparent from the following discussions, it is appreciated that throughout the present invention, discussions utilizing terms such as “determining” or “indicating” or “indexing” or “receiving” or “performing” or “initiating” or “sending” or “implementing” or “disabling” or “enabling” or “displaying” or the like, refer to the action and processes of a computer system or similar electronic computing device, that manipulates and transforms data represented as physical (electronic) quantities within the computer system&#39;s registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage, transmission or display devices. 
   The present invention is discussed primarily in the context of a portable computer system, such as a palmtop or personal digital assistant, with the capability to access via the Internet a World Wide Web (“Web”) site residing on a server computer system. However, it is appreciated that the present invention can be used with other types of devices that have a display screen and allow handwriting recognition as an input mechanism, including but not limited to laptop computer systems, cell phones, pagers, etc. 
   Exemplary Palmtop Platform 
     FIG. 1A  is a block diagram of an exemplary network environment  50  including a portable computer system  100 . Portable computer system  100  is also known as a palmtop or palm-sized computer system or as a personal digital assistant (PDA). In one embodiment, portable computer system  100  has the ability to transmit and receive data and information over a wireless communication interface (e.g., a radio interface). In one embodiment, the wireless communication interface is integrated into portable computer system  100 ; in another embodiment, the wireless communication interface is accomplished with a wireless modem attachment (not shown). 
   In the present embodiment, base station  32  is both a transmitter and receiver base station, which can be implemented by coupling it into an existing public telephone network  34 . Implemented in this manner, base station  32  enables portable computer system  100  to communicate with a proxy server computer system  36 , which is coupled by wire to the existing public telephone network  34 . Furthermore, proxy server computer system  36  is coupled to the Internet  52 , thereby enabling portable computer system  100  to communicate with the Internet  52 . Coupled with Internet  52  are multiple servers exemplified by server  30 . Residing on server  30  is a Web site  40 . When communicating with a Web site over Internet  52 , protocols such as CTP (Compact Transport Protocol) and CML (Compact Markup Language) can be used by portable computer system  100  in the present embodiment. 
   It should be appreciated that within the present embodiment, one of the functions of proxy server  36  is to perform operations over the Internet  52  on behalf of portable computer system  100 . For example, proxy server  36  has a particular Internet address and acts as a proxy device for portable computer system  100  over the Internet  52 . 
   It should be further appreciated that other embodiments of a communications network, planned or envisioned, may be utilized in accordance with the present invention. For example, a wireless connection may be made from portable computer system  100  directly to the Internet  52 . 
   The data and information that are communicated between base station  32  and portable computer system  100  is the same type of information and data that can conventionally be transferred and received over a public telephone wire network system. However, a wireless communication interface is utilized to communicate data and information between portable computer system  100  and base station  32 . It should be appreciated that one embodiment of a wireless communication system in accordance with the present invention is the Mobitex wireless communication system. 
     FIG. 1B  is a block diagram showing another embodiment of a system  51  for coupling a portable computer system  100  to other computer systems and to the Internet  52  in accordance with the present invention. System  51  is described in the context of wired connections between its various devices and components; however, it is appreciated that wireless connections (such as but not limited to Bluetooth wireless connections) can also be used. 
   With reference first to  FIG. 1B , system  51  comprises a host computer system  56  which can either be a desktop unit as shown, or, alternatively, can be a laptop system  58 . Optionally, one or more host computer systems can be used within system  51 . Host computer systems  58  and  56  are shown connected to a communication bus  54  such as an Ethernet Local Area Network (LAN), but which can instead be any of a number of other types. Bus  54  can provide communication with the Internet  52  using a number of well-known protocols. Coupled with Internet  52  are multiple servers exemplified by server  30 . Residing on server  30  is a Web site  40 . 
   Importantly, in the present embodiment, host computer system  56  is also coupled via connector cable  68  to a cradle  60  for receiving and initiating communication with portable computer system  100  (“handheld computer”) of the present invention. Connector cable  68  can be a serial bus (e.g., RS232), a parallel bus, a Universal Serial Bus (USB), or any other type of workable connection. Cradle  60  provides an electrical and mechanical communication interface between connector cable  68  and portable computer system  100  for two-way communications with host computer system  56 . Portable computer system  100  also contains a wireless infrared communication mechanism  64  for sending and receiving information from other devices. 
     FIG. 2  is a perspective illustration of the top face  100   a  of one embodiment of an exemplary palmtop computer system  100 . The top face  100   a  contains a display screen  105  surrounded by a bezel or cover. A removable stylus  80  is also shown. The display screen  105  is a touch screen able to register contact between the screen and the tip of the stylus  80 . The stylus  80  can be of any material to make contact with the screen  105 . The top face  100   a  also contains one or more dedicated and/or programmable buttons  75  for selecting information and causing the computer system to implement functions. The on/off button  95  is also shown. 
     FIG. 2  also illustrates a handwriting recognition pad or “digitizer” containing two regions  106   a  and  106   b . Region  106   a  is for the drawing of alphabetic characters therein (and not for numeric characters) for automatic recognition, and region  106   b  is for the drawing of numeric characters therein (and not for alphabetic characters) for automatic recognition. The stylus  80  is used for stroking a character within one of the regions  106   a  and  106   b . The stroke information is then fed to an internal processor for automatic character recognition. Once characters are recognized, they are typically displayed on the screen  105  for verification and/or modification. 
     FIG. 3  illustrates the bottom side  100   b  of one embodiment of the palmtop computer system that can be used in accordance with various embodiments of the present invention. An extendible antenna  85  is shown, and also a battery storage compartment door  90  is shown. A communication interface  180  is also shown. In one embodiment of the present invention, the communication interface  180  is a serial communication port, but could also alternatively be of any of a number of well-known communication standards and protocols, e.g., parallel, SCSI (small computer system interface), Firewire (IEEE 1394), Ethernet, etc. 
     FIG. 4  illustrates circuitry of computer system  100 . Computer system  100  includes an address/data bus  110  for communicating information, a central processor  101  coupled with the bus for processing information and instructions, a volatile memory  102  (e.g., random access memory, RAM) coupled with the bus  110  for storing information and instructions for the central processor  101  and a non-volatile memory  103  (e.g., read only memory, ROM) coupled with the bus  110  for storing static information and instructions for the processor  101 . Computer system  100  also includes an optional data storage device  104  (e.g., memory stick) coupled with the bus  110  for storing information and instructions. Device  104  can be removable. As described above, computer system  100  also contains a display device  105  coupled to the bus  110  for displaying information to the computer user. PC board  225  can contain the processor  101 , the bus  110 , the ROM  103  and the RAM  102 . 
   With reference still to  FIG. 4 , computer system  100  also includes a signal transmitter/receiver device  108 , which is coupled to bus  110  for providing a physical communication link between computer system  100 , and a network environment (e.g., network environments  50  and  51  of  FIGS. 1A through 1B ). As such, signal transmitter/receiver device  108  enables central processor unit  101  to communicate wirelessly with other electronic systems coupled to the network. It should be appreciated that within the present embodiment, signal transmitter/receiver device  108  is coupled to antenna  85  ( FIG. 4 ) and provides the functionality to transmit and receive information over a wireless communication interface. It should be further appreciated that the present embodiment of signal transmitter/receiver device  108  is well suited to be implemented in a wide variety of ways. For example, signal transmitter/receiver device  108  could be implemented as a modem. 
   In one embodiment, computer system  100  includes a communication circuit  109  coupled to bus  110 . Communication circuit  109  includes an optional digital signal processor (DSP)  120  for processing data to be transmitted or data that are received via signal transmitter/receiver device  108 . Alternatively, processor  101  can perform some or all of the functions performed by DSP  120 . 
   Also included in computer system  100  of  FIG. 4  is an optional alphanumeric input device  106  that in one implementation is a handwriting recognition pad (“digitizer”) having regions  106   a  and  106   b  ( FIG. 2 ), for instance. Alphanumeric input device  106  can communicate information and command selections to processor  101 . Computer system  100  also includes an optional cursor control or directing device (on-screen cursor control  107 ) coupled to bus  110  for communicating user input information and command selections to processor  101 . In one implementation, on-screen cursor control device  107  is a touch screen device incorporated with display device  105 . On-screen cursor control device  107  is capable of registering a position on display device  105  where the stylus makes contact. The display device  105  utilized with computer system  100  may be a liquid crystal display device, a cathode ray tube (CRT), a field emission display device (also called a flat panel CRT) or other display device suitable for generating graphic images and alphanumeric characters recognizable to the user. In the preferred embodiment, display device  105  is a flat panel display. 
     FIG. 5  is a perspective illustration of one embodiment of the cradle  60  for receiving the palmtop computer system  100 . Cradle  60  contains a mechanical and electrical interface  260  for interfacing with communication interface  108  ( FIG. 3 ) of computer system  100  when system  100  is slid into the cradle  60  in an upright position. Once inserted, button  270  can be pressed to initiate two-way communication (e.g., a communication session) between computer system  100  and other computer systems coupled to serial communication  265 . 
   On-Screen Text Correction of the Present Invention 
     FIG. 6A  illustrates an on-screen display (e.g., of a PDA or other portable computing device) including errors in a field of text  605  displayed on a touch-sensitive display screen  600  according to the present invention. The input cursor  606  is located at the end of the field. The first error noted  610  is the letter “l” in the misspelled word “quicl,” which of course should be the letter “k.” The second error  620  is the letter “u” in the misspelled word “broun”, which of course should be the letter “w.” 
     FIG. 6B  illustrates text as displayed on a touch-sensitive display screen in  FIG. 6A   605  in which errors have been corrected according to the present invention. The input cursor  606  is located at the end of the field. The letter “k”  630  has been inserted to correct the spelling of the work “quick.” The letter “w”  640  has been inserted to correct the spelling of the word “brown.” 
     FIG. 7  illustrates the placement of letters formed by handwritten strokes  700  to be inserted in place of incorrect letters in existing text displayed on a touch-sensitive display screen according to the present invention. The text containing errors  705  is at the top of the field, and the cursor  706  is located at the bottom of the field. In this illustration, the erroneous letter “l”,  610  in  FIG. 6A , is to be replaced with the correct letter “#k.” 
   To perform this correction using the invention, the user uses a stylus to handwrite the letter “c”  710  in proximity to the letter “c” in the existing word “quicl.” Again, using a stylus, the user handwrites the letter “k”  720  adjacent and to the right side of the letter “c”  710 . In these cases, the user is writing directly on the touch sensitive screen  105  ( FIG. 4 ). After a brief pause in writing (or until the system determines an unambiguous match between the correction characters and the existing text), the system then recognizes that the user has stopped entering correction characters (“c and k”). This causes the system to identify the text that is nearby the correction characters and identify matches between the correction characters and characters of the text. Detecting a match between the written letter “c”  710  and the existing letter “c”, causes characters in the word “quicl” beginning with and following the existing letter “c” to be replaced with the handwritten letters “c” and “k.” The misspelled word “quicl” has thus been corrected to “quick.” 
   More particularly, the computer system recognizes the match between the “c” and determined that “ck” (the correction text) would replace “cl.” A correction cursor is not required. Specific deletion steps are also not required. 
     FIG. 8  illustrates the placement of letters formed by handwritten strokes  800  to be inserted in place of incorrect letters in existing text displayed on a touch-sensitive display screen according to the present invention. The text containing errors  805  is at the top of the field, and the cursor  806  is located at the bottom of the field. In this illustration, the erroneous letter “u”,  620  in  FIG. 6A , is to be replaced with the correct letter “w.” Using a stylus, the user handwrites the letter “w”  810  in proximity to the letter “u” in the existing word “broun.” Again, using a stylus, the user handwrites the letter “n”  820  adjacent and to the right side of the letter “w”  810 . 
   In accordance with embodiments of the present invention, detecting a match between the written letter “n”  820  and the existing letter “n”, causes characters in the word “broun” beginning with and preceding the existing letter “n” to be replaced with the handwritten letters “w” and “n.” The misspelled word “broun” has thus been corrected to “brown.” A correction cursor is not required. Specific deletion steps are also not required. 
     FIG. 9  is a flowchart  900  showing steps in a process for modifying data displayed on a touch-sensitive display screen according to an embodiment of the present invention. The steps of process  900  may be implemented as memory resident computer code executed by processor  101 . 
   At step  910 , a first text portion is entered, e.g., by a user. The cursor may be used to enter this first text portion, e.g., by directing entry of the characters into a specific on-screen window or data entry field. In this first text portion there is assumed to be a mistake that needs to be corrected. A portion of data to be modified is identified as a group of adjacent characters separated on each side from other characters by one or more anchor characters, e.g., spaces (a single word for example). In step  910 , the user may leave the cursor at the end of the field in which the data to be modified is located. 
   At step  920 , a user enters the modification mode of operation by positioning the cursor over the first text portion and then stroking the stylus to enter a correction character. The user stroking a stylus on the surface of the touch-sensitive screen in step  920  forms a replacement or correction character in the vicinity of an existing character to be modified or in the vicinity of a word containing an error therein. The correction characters may be written (e.g., graphically displayed) over the first text portion (e.g., using electronic ink). At step  930 , if no pause is encountered after the correction character is entered, or, if no unambiguous match is found between the correction character and the first text portion, then step  935  and step  920  are entered to allow the user to enter another correction character. It is appreciated that as the correction characters are being written, automatic handwriting recognition processes are being applied to recognize them. 
   After a recognized pause, the system will compare the correction characters against the first text portion to locate an unambiguous match and then step  940  is entered. The computer system examines the correction characters that were just entered against the text (e.g., first text portion) that is nearby the correction characters in order to locate a unique match between the correction characters and the existing text. This may cause an audible tone to be generated. If a match is located, then the computer system (at step  940 ) replaces a portion of the existing text with the correction text. For instance, with respect to the work “quicl” the matching character was “c” and the text “cl” was replaced by the correction text “ck.” 
   Alternatively, at step  930 , even if there is no pause, the system may locate an unambiguous match (at step  930 ) between the correction characters and the first text portion thereby causing step  940  to be entered. 
   At step  940 , the correction characters are automatically inserted into the first text portion in place of existing characters using the matching characters for proper location and character alignment. This generates a second text portion. At step  945 , the second text portion is displayed on the screen and an audible tone may occur. If more corrections are required, step  920  can be entered again. Step  950  allows the opportunity to perform additional modifications in a selected portion of data, in which case, the system remains in the modification mode by returning to step  920 . If no additional modifications are requested, the system exits the modification mode. 
   Within process  900 , the processor examines the nearby text for anchor points that match the correction text. In one embodiment, the processor will replace all text from an anchor point to the end of a word, e.g., as determined by a space, period or comma, etc. In the following example, the existing text is “your” and the correction text is “rs” which yields “yours” on correction. The anchor is “r” and the correction continues until the end of the word is reached. In another embodiment, the processor will replace all text located between two recognized anchor points. In the following example, the existing text is “elephint.” The correction text is “han” yielding “elephant” on correction. The anchor characters are “h” and “n” thereby causing all characters in between to be replaced. In another embodiment, the processor will replace all text that precedes an anchor point. In the following example, the existing text is “nungry” and the correction text is “hu” which yields “hungry” on correction. The anchor is “u” and the correction continues backwards the start of the word is reached. 
   Also, a handwritten character stroke that directly overlies an existing character may replace that single character. A handwritten character that is identified as similar to an existing character replaces that existing character, and any handwritten characters to the right of the similar handwritten character replace existing characters in corresponding positions to the right of the similar existing character. A handwritten character that is identified as similar to an existing character replaces that existing character, and any handwritten characters to the left of the similar handwritten character replace existing characters in corresponding positions to the left of the similar existing character. 
   After the replacement text is displayed, an optional audible tone may be generated. 
   The preferred embodiment of the present invention, method and process for on screen text correction via pen interface, is thus described. While the present invention has been described in particular embodiments, it should be appreciated that the present invention should not be construed as limited by such embodiments, but rather construed according to the below claims.