Abstract:
During handwriting recognition input, when the user needs to input, e.g., a digit or a commonly used punctuation symbol (e.g. comma and period) into a text, she/he can simply make a single-click or a double-click on a corresponding “shortcut” sub-area on the touchpad under the existing input mode and the digit or punctuation symbol will be input. The “shortcuts” of the grid are advantageously arranged as the layout of the dial keys of telephones, which is easy to remember.

Description:
TECHNICAL FIELD  
       [0001]     The present invention relates to a method and apparatus as well as a computer program for controlling a mobile communication terminal that is capable of handwriting recognition.  
       BACKGROUND  
       [0002]     Mobile telephones have evolved during the last few years from being simple voice communication devices to present day intelligent communication terminals having processing and communication capabilities that were almost unimaginable not long ago. Needless to say, the use of a mobile telephone now involves such communication intensive activities as sending e-mail messages, browsing the World Wide Web as well as other activities such as managing calendar functions and playing games. A strong driving force during the development of present day communication devices has been that of user demand for miniaturization and reduced weight. This has, however, resulted in manufacturers of devices having been forced to compromise between physical size and usability in terms of providing an easy to use user interface. For example, a typical mobile telephone is equipped with a small keypad, often comprising no more than fifteen small keys that have multiple input functions.  
         [0003]     A problem relating to present day communication devices is hence that of providing an easy way of inputting text into a communication device, e.g. text input when recording information in a calendar application or text input when composing an e-mail message or a Short Message Service (SMS) message.  
         [0004]     Prior art methods and devices have approached this problem in a number of different ways. One example is that of utilizing a touch sensitive pad or a touch sensitive display on which a user enters text and other input information by writing with, e.g., a small stylus as if writing with a pen on paper. The movement of the stylus along a trace over the touch sensitive pad or display generates a trace signal that is digitized and analyzed by handwriting recognition procedures that typically are implemented by means of software instructions.  
         [0005]     However, in some situations the recognition procedures may be unable to resolve a trace signal into a desired symbol. This may be due to a situation where there exist ambiguities regarding symbols or parts of symbols being very similar, or simply be due to inaccurate handwriting by the user. One example of such an ambiguity is the punctuation symbol “,” (comma) and a carriage return.  
         [0006]     Prior art solutions to this problem typically involve switching the device from an input mode where handwriting recognition is used into an input mode where, for example, a keyboard is used. One example of such prior art is the “Sony Ericsson P900 smartphone”. The user switches to keyboard-mode by tapping on a keyboard symbol on the touch sensitive display. A keyboard is then displayed and the user may enter a desired symbol by tapping on the appropriate key.  
         [0007]     A drawback of such a solution is that it is inefficient in terms of the time it takes to enter symbols. Particularly time consuming and complicated is the case where, as in the Sony Ericsson P900; a plurality of different keyboards are provided for the user to select among, e.g. one keyboard comprising mostly special characters and one keyboard comprising mostly numerical keys.  
       SUMMARY OF THE INVENTION  
       [0008]     An object of the present invention is hence to overcome the drawbacks with prior art devices.  
         [0009]     This object is achieved by way of a method, a mobile communication terminal and a computer program according to the appended claims.  
         [0010]     That is, in a first aspect, an inventive method of controlling a mobile communication terminal overcomes the drawbacks of prior art. The terminal comprises a control unit, a display and touch sensitive means configured to recognize handwriting via trace signals generated as a user writes within a hand writing recognition area on the touch sensitive means The method comprises, while sensing and analyzing a trace signal comprising a sequence of position detections, recognizing a tapping action, e.g. single clicking or double clicking, at a detected action position, selecting a specific symbol from a set of predetermined symbols, said selection being performed in dependence of the detected action position, and providing the selected symbol for use in said control of the mobile communication terminal.  
         [0011]     Preferably, the symbols in the set of predetermined symbols are associated with respective sub-areas, e.g. arranged in rows and columns, within the writing recognition area and the selection is performed in dependence on within which sub-area the action position is.  
         [0012]     The predetermined set of symbols may in preferred embodiments of the invention comprise the sequence of digits 0 to 9 and/or at least one punctuation symbol.  
         [0013]     The control of the terminal may in preferred embodiments of the invention comprise a text editing operation.  
         [0014]     That is, during handwriting recognition input, when the user needs to input, e.g., a digit or a commonly used punctuation symbol (e.g. comma and period) into a text, she/he can simply make a single-click or a double-click on a corresponding “shortcut” sub-area on the touchpad or touch sensitive display under the existing input mode and the digit or punctuation symbol will be input. This in contrast to prior art solutions where typically a switch of input mode is performed by clicking a mode switch button etc. The “shortcuts” of the grid are advantageously arranged as the layout of the dial keys of telephones, which is easy to remember.  
         [0015]     The invention is advantageous when utilized in connection with handwriting recognition of, e.g., Chinese characters or any other similar character set comprising graphically complex characters consisting of a plurality of lines, curves and dots. Digits are then entered, during handwriting recognition of the complex characters, by double-clicking in the appropriate sub-area. Double-clicking is particularly suitable since such a tapping action is easily distinguishable from the handwriting action that is to be recognized as a dot, which may be part of a desired character being written.  
         [0016]     In a second aspect, the invention provides a mobile communication terminal comprising a control unit, a display and touch sensitive means that are configured to recognize handwriting via trace signals generated as a user writes within a hand writing recognition area on the touch sensitive means. The terminal further comprises control means for sensing and analyzing a trace signal comprising a sequence of position detections, recognizing means for recognizing a tapping action at a detected action position, selection means for selecting a specific symbol from a set of predetermined symbols, said selection being performed in dependence of the detected action position, and provision means for providing the selected symbol for use in said control of the mobile communication terminal.  
         [0017]     In preferred embodiments are the touch sensitive means arranged in combination with the display thereby constituting a touch sensitive display.  
         [0018]     In other preferred embodiments are the touch sensitive means arranged separately with respect to the display thereby constituting a touch sensitive pad.  
         [0019]     In a third aspect, the invention provides a computer program comprising software instructions that, when executed in a mobile communication terminal as described above in connection with the second aspect of the invention, controls the terminal as described above in connection with the first aspect of the invention.  
         [0020]     An advantage of the present invention is that it increases the rate at which a user can enter symbols into a mobile communication terminal. Moreover, since the input of, e.g., digits and punctuation marks is made not by hand writing recognition, but rather by an equivalent of pressing a key on a keyboard, the accuracy is effectively total.  
         [0021]     Because of the fact that the invention, in preferred embodiments, is implemented by means of software instructions in already existing mobile communication terminals, an advantage is that it provides an easy and inexpensive way of adding functionality. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0022]      FIG. 1  shows a schematically drawn block diagram of an embodiment of a mobile communication device according to the present invention.  
         [0023]      FIG. 2  illustrates a schematically drawn block diagram of an embodiment of a mobile communication device according to the present invention.  
         [0024]      FIGS. 3   a  and  3   b  illustrate a device according to the present invention having a touch sensitive display.  
         [0025]      FIG. 4  illustrates a device according to the present invention having a touch sensitive pad.  
         [0026]      FIG. 5  is a flow chart illustrating an embodiment of a method according to the present invention. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0027]      FIG. 1  illustrates schematically a communication device in the form of a mobile telephone terminal  100  in which the present invention is implemented. The telephone  100  is capable of communication via an RF-unit  116  and an antenna  118  through an air interface  113  with a mobile (radio) communication system  115  such as the well known systems GSM/GPRS, UMTS, CDMA 2000 etc.  
         [0028]     The terminal  100  comprises a processor  104 , memory  108  as well as input/output units in the form of a speaker  110 , a microphone  112 , a keyboard  114  and a touch sensitive display  102  on which a user writes using, e.g., a stylus or similar device. The input/output units communicate with the processor  104  through an I/O-interface  106 . The details regarding how these units communicate are known to the skilled person and is therefore not discussed further. The communication terminal  100  may, in addition to the illustrated mobile telephone terminal, a Personal Digital Assistant (PDA) equipped with radio communication means.  
         [0029]     The method according to the preferred embodiments of the present invention will in general reside in the form of software instructions of a computer program  109  with an associated memory area  111 , together with other software components necessary for the operation of the terminal  100 , in the memory  108  of the terminal  100 . The computer program  109  may be resident or it may be loaded into the memory  108  from a software provider, e.g. via the air interface  113  and the network  115 , by way of methods known to the skilled person. The program  109  will be executed by the processor  104 , which will receive and process input data from the different units in the terminal  100 , particularly input data in the form of trace signals from the touch sensitive display  102 , where the trace signals represent traces and other actions performed by the user using, e.g., a stylus to write on the touch sensitive display.  
         [0030]     A second embodiment of a communication device according to the present invention is illustrated in  FIG. 2 . Similar to the device discussed above in connection with  FIG. 1 , a mobile telephone terminal  200  is capable of communication via an RF-unit  216  and an antenna  218  through an air interface  213  with a mobile (radio) communication system  215  such as the well known systems GSM/GPRS, UMTS, CDMA 2000 etc.  
         [0031]     The terminal  200  comprises a processor  304 , memory  308  as well as input/output units in the form of a speaker  310 , a microphone  212  and a keyboard  214 . In contrast to the example described above, the terminal  200  comprises a touch sensitive pad  202  on which a user writes using, e.g., a stylus or similar device. A display  203  is used to present information to the user. These input/output units communicate with the processor  204  through an I/O-interface  206 .  
         [0032]     As in the example discussed above, software instructions of a computer program  209 , for performing the invention, with an associated memory area  211 , together with other software components necessary for the operation of the terminal  200 , reside in the memory  208  of the terminal  200 . The computer program  209  may be resident or it may be loaded into the memory  208  from a software provider, e.g. via the air interface  213  and the network  215 , by way of methods known to the skilled person. The program  209  will be executed by the processor  204 , which will receive and process input data from the different units in the terminal  200 , particularly input data in the form of trace signals from the touch sensitive pad  202 .  
         [0033]     A method according to the present invention will now be described with reference to  FIGS. 3   a ,  3   b ,  4  and  5 . The method will typically be realized by means of a computer program, e.g. the computer programs  109  and  209  discussed above in connection with  FIGS. 1 and 2 . The computer program will utilize a part of memory, e.g. corresponding to the memory area  111  and  211  in  FIGS. 1 and 2 , respectively.  
         [0034]     With reference to  FIGS. 3   a  and  3   b , a mobile communication terminal  300  comprises a touch sensitive display  302 , a loudspeaker  312 , a microphone  314  and a keypad having a plurality of control keys  316 . As the skilled person will realize, the terminal  300  may be of the kind described above in connection with  FIG. 1 .  
         [0035]     The touch sensitive display  302  is configured to sense hand writing, by means of a stylus or other suitable implement, within a hand writing recognition area  304  and configured to sense tapping actions within a function area  306 , which is divided into four areas assigned to specific functions or symbols as shown in the figure. A grid  310  is displayed within the hand writing recognition area  304  and within sub-areas  308  defined by the grid  310  are symbols displayed. In  FIG. 3   a  the symbols in the sub-areas  308  are the digits 0 to 9 as well as the common punctuation marks “,” (comma) and “.” (period).  
         [0036]     Hand writing within the hand writing recognition area  304  will result in a sequence of detected positions being input to appropriate recognition procedures in the controlling hardware and software in the terminal. A detection of a tapping action within any of the sub-areas  308  of the grid  310  will result in a detection of a corresponding symbol, i.e. a symbol as displayed at the tapping action position. Tapping within the function area  306  will result in any appropriate action within the terminal, as the skilled person will realize, including a re-definition of the set of symbols associated with the sub-areas  308  of the grid  310 . Such a situation is in fact illustrated in  FIG. 3   b , where the sub-areas  308  comprise a more extended set of punctuation symbols.  
         [0037]      FIG. 4  illustrates another embodiment of a mobile communication terminal  400  according to the invention. As for the terminal  300  described above, the terminal  400  comprises a loudspeaker  412 , a microphone  414  and a keypad having a plurality of control keys  416 . In contrast to the terminal  300  described above, a display  402  and a touch sensitive pad  403  are in the terminal  400  separate units and are spatially separated on the terminal  400  front. Nevertheless, the touch sensitive pad  403  is configured with a hand writing recognition area  404  to function in the same manner as the touch sensitive display  302  of the terminal  300  in  FIG. 3 , one difference being that a grid  410  and corresponding sub-areas  408  with their associated symbols remain fixed. Preferably, the grid  410  and the symbols within the sub-areas  408  are printed during manufacture, or in any suitable way marked on the pad  403 . As the skilled person will realize, the terminal  400  may be of the kind described above in connection with  FIG. 2 .  
         [0038]     A method according to the invention will now be described with reference to a flow chart in  FIG. 5 . The method may be effectuated in control circuitry and software instructions in any of the embodiments of a terminal described above in connection with FIGS.  1  to  4 .  
         [0039]     As the skilled person will realize, the method may form part of a more complex control system and as such takes place while sensing and analyzing a trace signal comprising a sequence of position detections when an implement such as a stylus is used by a user writing within a writing recognition area on a touch sensitive display or pad.  
         [0040]     In a position detection step  501 , a position (e.g. coordinates representing a position) of a writing implement is detected. The detected position is, in a checking step  503 , analyzed to the extent that it is possible to determine whether or not the detected position forms part of a trace that is to be interpreted and analyzed in a hand writing recognition procedure. If it is determined that the detected position is part of a trace, the detected position is recorded in a recording step  504  and the method returns to the detection step  501 . If it in the checking step  503  is determined that the detected position is not part of a trace, the detected position is interpreted as being a tapping action in an action determination step  505 . The tapping action may, e.g., be determined when a “single-click” or a “double-click” is detected. In an association step  507 , the detected position of the tapping action is then used in selecting a specific symbol from a set of predetermined symbols, where the selection is performed in dependence of the detected action position. For example, the action position is compared with a set of coordinates that define sub-areas (cf.  FIGS. 3 and 4 ) and associated symbols, yielding a match whereby the desired symbol is identified. The symbol is then provided, in a provision step  509 , to the controlling procedure, for example a text editing operation.