WO2002103619A1

WO2002103619A1 - Presentation of a recognition of a handwritten pattern

Info

Publication number: WO2002103619A1
Application number: PCT/SE2002/001151
Authority: WO
Inventors: Martin Lindberg; Magnus Nordenhake
Original assignee: Decuma Ab
Priority date: 2001-06-20
Filing date: 2002-06-14
Publication date: 2002-12-27
Also published as: KR20040015745A; CN1520574A; JP2004534312A; KR100934780B1

Abstract

A method for presentation of a recognition of a handwritten pattern comprises the steps of detecting a handwritten pattern that is entered by a user on an input area on a screen, and recognizing the detected handwritten pattern. The step of recognizing returns a best interpretation of the handwritten pattern and at least one alternative interpretation of the handwritten pattern. The method further comprises the steps of presenting the best interpretation in a presentation area on the screen, wherein the presentation area overlaps the input area, and presenting the at least one alternative interpretation in the presentation area. A device for recognition of a handwritten pattern comprises a screen for user interaction, which screen comprises an input area, which is sensitive to handwritting, and a presentation area, which overlaps the input area.

Description

Presentation of a recognition of a handwritten pattern

Technical Field of the Invention

This invention relates to a method for presenting a recognized handwritten pattern. The invention also relates to a device for recognition of a handwritten pattern. The device comprises a screen for user interaction, which screen comprises an input area that is sensitive to handwriting.

The present invention also concerns a method and a device for presenting a pattern, and in particular a method and a device for presenting a pattern on a background .

Background of the Invention

Today, portable data handling devices are becoming increasingly popular. These data handling devices are e.g. PDAs (Personal Digital Assistants), mobile phones and portable computers. In order to enter data into these portable devices, a text insertion unit is needed.

Text insertion units have formerly been implemented as keyboards. This, however, sets limits to the minimum size of the portable device, and therefore a different way of inserting text into the device is needed in order to enable smaller devices.

In such devices, the keyboards can now be replaced by some kind of device for recognition of handwritten text. A common solution is to arrange a pressure-sensitive area on a screen where a user can write characters. The characters are then interpreted and processed by the portable device. It is, of course, also of interest to replace keyboards of regular stationary computers.

The screen displays a user interface for entering of text. The screen has an input area, where the user can enter handwritten characters, and a presentation area, where the result of the recognition of the handwritten characters is displayed to the user.

In US 5,732,152, a user interface is disclosed. The input area comprises character entry boxes, which define areas for entering of a handwritten character. A handwritten character is entered inside a box and the result of the recognition then replaces the handwritten character in the box. The result is also shown in a second display field. According to US 5,732,152, a character representing non-recognition is displayed when the recognition of a handwritten character has failed. The user will then have to re-enter that character so that it can be correctly recognized. As a result, the user could have to enter a character several times before it is recognized by the device. This is time-consuming and irritating to the user. Furthermore, there is no guarantee that characters, which have been recognized by the device, are correct. The device could have made an incorrect recognition. The user will have to re-enter the character in these cases as well.

In Chinese character recognition, it is common to show candidates of the recognition in a presentation area, as shown in Fig. 1. The user will then have to choose the correct candidate for the character to be correctly recognized. As a result, a process of entering a character involves two steps. Firstly, the user enters the character and secondly, the user chooses the correct recognition of the character. This is time-consuming and much slower than writing on a piece of paper.

Further, for computer displays it is known to use special characters with special assigned meaning in order to distinguish characters, which would else be similar in appearance, and therefore easily confused. For programming purposes a circle with a slanted line, "0", has been used to distinguish the number zero from the letter o. This method suffers from the drawback that it is necessary to use a special character with a special assigned meaning for each easily confused character, and a user should further learn each such special assigned meaning. As some languages use several thousands of characters, this method is not practical for such languages .

Examples of such languages are Chinese and Japanese. Contemporary Japanese uses a mixture of characters, comprising Japanese kanj i (symbolic characters of Chinese origin) , hiragana and katakana (phonetic characters) , Latin letters and Arabic numerals.

In conjunction with handwriting recognition (H R) it is preferable that a user is provided with information about the characters she has been writing. This has spe- cial importance when e.g. writing a user id or a password, or when submitting a query to a database.

One method of emphasizing the difference between different types of characters has been provided in connection with e.g. the input method editor (IME) available on the Toshiba Pocket PC Genio e550X for Japanese. The difference between hiragana and katakana is indicated in writing besides candidates, identified by the used HWR software. See Fig. 1 for illustration.

Some problems are associated with this method. Firstly, a large area of the available screen space is neccessary for indicating the various types of characters of the candidates. Thus, only a few candidates may be presented at a time if the occupied screen space is to be kept small. Further, a correct candidate is not easily found in the list, since a user will first need to find a candidate having the correct appearance and then check the writing beside the candidate to control that the candidate belongs to the correct type of character.

There exists a need for improved ways of indicating the types of characters presented on a screen, without wasting the area of screen, and with the possibility to ascertain the type of character presented. In devices for Chinese character recognition, character entry boxes are also common. The character entry boxes normally cover the whole input area. The user has to write the character inside the character entry box. This may lead to the fact that the user writes a small character in order to be sure that the whole character is entered inside the box. As a result, the demand on handwriting precision becomes higher. This is especially a problem when the user is using the device in a shaky en- vironment, e.g. while travelling in a car, or when the user writes quickly. In these circumstances, the recognition can fail if the user writes so small letters that he reaches a precision limit of the device.

Summary of the Invention

It is an object of the present invention to provide an improved user interface for a device for recognition of a handwritten pattern. Another object of the invention is to provide a user interface, which simplifies input of handwritten characters.

The objects of the invention are achieved by a method according to claim 1 and a device according to claim 28. Preferred embodiments of the invention are defined by the dependent claims 2-27 and 29-34. Thus, the present invention provides a method for presenting a recognized handwritten pattern. The method comprises the steps of detecting a handwritten pattern that is entered by a user on an input area on a screen and recognizing the detected handwritten pattern. The step of recognizing returns a best interpretation of the handwritten pattern and at least one alternative interpretation of the handwritten pattern. The method further comprises the steps of presenting the best interpretation in a presentation area on the screen, wherein the presen- tation area overlaps the input area, and presenting the at least one alternative interpretation in the presentation area.

symbol could also be an abbreviation for a longer, commonly entered phrase or word. For example, a symbol of two merged letters which are a person's initials may represent the person's whole name. According to an embodiment, the at least one alternative interpretation is presented at the same time as the best interpretation. Then, if the best interpretation is not correct, an alternative interpretation, which may be correct, is immediately presented to the user during recognition. As a result, the user may easily choose an alternative interpretation for controlling the interpretation of the entered pattern. The correction of the best interpretation is thus easily performed. Further, since the alternative interpretation is also presented in the presentation area which overlaps the input area, the user may still be focussing on the same area.

Preferably, the best interpretation is presented in a larger scale than the at least one alternative interpretation. This implies that the best interpretation is clearly marked to the user so that the user will know which interpretation the device will use if he does not correct it .

The at least one alternative interpretation may be presented at the same time as the best interpretation only where distinguishing between the best interpretation and the at least one alternative interpretation during the step of recognizing is difficult. If several interpretations are presented at the same time, it may not be obvious to the user which interpretation is the best. Thus, the user may not know which interpretation the device chooses if the user does not correct it. Therefore, it may be suitable to only show alternative interpretations where the step of recognizing returns two or more interpretations that are almost equally likely to be the correct interpretation.

Where two patterns are very similar, such as "0" (Arabic numeral zero) or "0" (Latin capital letter O) , it is very difficult to distinguish between these handwritten patterns, and correctly recognize them. In this case, if one of these patterns is returned as the best interpretation, the other pattern may be automatically pre- sented as an alternative presentation at the same time as the best interpretation is presented. As a result, a user may quickly switch to the correct interpretation, if the wrong pattern is presented as the best interpretation. According to another embodiment, the step of pre- senting the at least one alternative presentation is made at the request of a user. Preferably, the device further comprises means for requesting the presentation of the at least one alternative interpretation of the entered pattern. The user could then request a presentation of al- ternative interpretations, which enables the user to choose the correct interpretation . from the presented alternatives. Thus, re-entering of the character could be avoided. Further, only the best interpretation is initially presented to the user, whereby the user will not be confused by a presentation of several alternatives, when the handwritten pattern is recognized. This is a very efficient way of presenting interpretations to the user, if the recognition mostly returns correct interpretations . In a preferred embodiment of the method, the step of presenting the alternative interpretation replaces the presented best interpretation. Preferably, the presentation area is arranged to present the alternative interpretation at the request of a user via the means for re- questing. When the user requests presentation of the alternative interpretations, the best interpretation is incorrect and does not need to be presented any longer. Since the alternative interpretations replace the best interpretation, only the information needed by the user is presented to him. Furthermore, the user can still keep focussing on the same place on the screen. As a result, all user interactions are in the same place, which makes the input efficient and the device easy to handle.

Preferably, the steps of presenting interpretations replace the entered handwritten pattern. This also re- suits in only the information needed by the user being presented to him. When the user has entered a pattern, he only needs to see how the entered pattern is interpreted. Thus, only the relevant information is presented to the user and all information is presented in the same place on the screen. Therefore, the input process is simple. The method may comprise the step of presenting at least one suggestion for a pattern that is to follow or precede the recognized handwritten pattern. This implies that the user will not need to enter the next pattern by handwriting. Instead, the user may accept a suggestion that the device presents as a likely pattern to follow the interpreted handwritten pattern. Further, a preceding pattern that has been incorrectly accepted need not be re-entered. In this way, the device may present a likely pattern to precede the latest interpreted handwritten pattern. Several suggestions may be determined through bigram statistics, whereby the suggestions may be returned and presented as alternative interpretations. Bigram statistics is statistics over the probability that a specific pattern or character is followed by another specific pattern. The bigram statistics may differ depending on e.g. what language is used. The user may choose a domain of bigram statistics that suits the text that he is to enter. The suggestions may be presented upon request from the user, such as activating a button on the screen or drawing a specific gesture.

According to a preferred embodiment, the step of recognizing returns several alternative interpretations and the step of presenting alternative interpretations presents all the returned alternative interpretations. As a result, the user will be shown several alternatives. The correct recognition will then probably be presented

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Hi 3 s: Φ Hi CO P- SD Ω Φ rt Φ c rt P- C Hi tr rt rt P- Hi rt Φ Φ

Ω rt P- fi SD 3 Hi Ξ Ω 3 rt Hi h-¹ 3- Φ O rt 3 TJ CQ Φ 0 if Q 0 ED 3 Φ g

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defined by two opposite lines and imaginary lines connecting these lines for defining the area.

Preferably, the step of presenting guidance lines imitates the appearance of a writing paper. As a result, the user is familiar with the appearance of the input area. The entering of characters will thus be natural to the user.

For Chinese characters, the invention is advantageous by allowing input outside the principal entering area. This is due to the fact that it is common in normal writing of Chinese characters on paper to let the characters extend somewhat outside boxes on the paper. The guidance lines could then form boxes for entering characters, where the user can enter the characters in the same way as he is used to when writing on paper. This will lead to a better recognition of the character.

According to an aspect of the invention, there is provided a method for presenting a pattern while providing information of the type of pattern. According to an aspect of the invention, there is provided a method for presenting a pattern in a presentation area of a screen, said pattern being presented on a pattern background visible on a part of said presentation area of said screen, said pattern background being asso- ciated with said pattern, wherein a combination of said pattern with said associated pattern background is presented in a masked form, the masking of said combination being selected according to the type of pattern presented. In an application of this method, masking or alteration of the combination may be applied for only some of the presented patterns.

The masking may comprise no change or a change of the appearance of said combination, depending on the type of the pattern to be presented, as long as different types of masking is applicable to different types of patterns. This allows the visual difference between differ- ent similar patterns to be enhanced by applying different kinds of masking. For distinguishing between different patterns, it may be sufficient to alter one of a pair of similar patterns. The correspondence between the type of masking and the type of pattern may be predetermined, and may be altered.

As described above, handwriting recognition is often associated with uncertainty with respect to the correct determination or interpretation of the intended pattern. The user will therefore need feedback in order to ascertain whether the pattern has been correctly identified. The method according to the invention, wherein the masking of a combination of the pattern with the associated pattern background is selected according to the type of pattern presented, may help in emphasizing the different types of patterns as a feedback to the user.

In many cases different patterns may be written in the same or nearly the same way. Thus, using only the in- formation from the specific pattern it may be difficult or even impossible to identify the correct pattern, intended by the user. Here, giving the user an overview of candidates for the correct pattern may help, as the user can then choose between the candidates . According to another aspect of the present invention, each pattern is associated with a pattern background, each combination of each said pattern and each said associated pattern background being masked according to the type of each said pattern. When a number of patterns are presented it may be helpful for a user to be provided with information concerning the types of patterns presented, for rapid and easy recognition and interpretation. This aspect is especially of use when errors in input have to be detected. According to another aspect of the present invention, the presented patterns are displayed along horizontal or vertical lines. Horizontal and/or vertical align- ment of patterns help a user in interpreting any semantic or symbolic meaning imbedded in the patterns.

According to another aspect of the present invention, the sizes of the areas of the associated back- grounds are equal or different. The method may be applied to cases where patterns are proportionally as well as un- proportionally spaced. The method can be used with patterns of similar and/or dissimilar width and/or height. The method may thus be used for emphasizing the differ- ence between e.g. full-width and half-width characters.

Optionally the width and/or height of the patterns may be adjusted for masking.

According to another aspect of the present invention, the method comprises the steps of: a) identifying the type of pattern to be presented; b) selecting the type of masking corresponding to the type of the pattern; c) presenting the combination of said pattern with said associated pattern background on said screen while applying the appropriate masking for said combination.

A such masking routine may implement the method according to the invention, and would be implementable for the average person skilled in the art.

According to another aspect of the present inven- tion, a viewer of a presented pattern may choose the type of masking associated with the type of said pattern. According to this aspect, a viewer or a user may choose the type of masking associated with each type of pattern, in order to improve the identifiability of the pattern, to satisfy personal taste, or to adjust the method to the screen used.

According to a further aspect of the present invention, said masking comprises changing the appearance of said combination. For presentation on a screen a visual change of the combination is easily applicable. However, e.g. sound may be used, for notifying a user that a certain type of pattern is being presented. O LO to t H P¹ π O LΠ o LΠ o LΠ

rt a SD Ω rt P- CO <

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LQ Hj 3 CQ Φ P-

ΪY > P- TJ fi o >

> SD rt Ω CQ Φ φ 3 Ω

Hj 3 tr Ω Φ SD Ω P- Ω

SD L-J. Φ 0 CQ P- 3 0 tr p. Hi 0 P- ED rt CQ Hj

P- LQ fi Hj -¹ Φ ED fi

Ω Hj P- *< Hj P- P- tr 0 3 Ω ; TJ fi 3

3 P. c LQ 0 Ω Hj LQ c p, TJ 3 0 CO Φ 3^*

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CD P- 0 Si h-¹ 3 P- rt

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ED SD P- TJ SD 3" Hi Ω Φ 3

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>T rt tr ED TJ TJ if

T SD 0 _^ ED Ω Φ Hj ED Φ

C 3 Hi Hj rt 3 P- rt Hj

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SD Oi 3 Ω Hj P- φ rt rt Φ tr ι-3 3 Ω SD Ω

P- P- CQ ED tr LQ tr 3 rt

0 3 Φ Hj c ED fi

3 ED CO rt Hj 0

Ω Ω if SD Hi

3 Φ tr rt Φ Ω rt

SD rt ED φ rt rt tr rr hj rt Hj Hj 3- fi Φ f- if

X Φ SD Φ P- Hj CQ Φ O Hj Ω P- Hi

CO rt CQ TJ Hi TJ

Φ ED Φ H rt Hi

H H{ CO rt Hj tr tr Φ tf Q O Φ rt Φ Φ φ O

Φ h{ h-¹ Φ 3 φ

CO Φ Φ Hj Ω 3 TJ 3 φ Φ Ω

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acters are examples of widely used characters, which in certain cases may be confused due to similar appearance.

According to an aspect, said masking is selected according to the type of said character, said type being selected among the group consisting of the types Chinese characters, Japanese kanji , hiragana, katakana, Latin letters, Greek letters, Arabic numerals, and punctuation marks. Presenting information identicating the type may help lowering the probability of incorrect choice, input or identification of a character.

As exemplified in the table below, among the mentioned types are a number of easily confused characters.

Table I

According to an aspect, the selected masking depends on the type of encoding form of the character. When using LO LO t NJ

LΠ O LΠ o LΠ o LΠ

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Φ P- Hi SD ED fi 3 Φ rr P- Φ 3 Ω Hj P- SD n if H{ rt 0 X rr rr rr c ED Φ rr 3 if . rt 0 φ CD P- SD LQ Hi Φ Si Hj TJ Ω Φ o rt ^ φ SD rt SD SD ED Φ h-¹ 3 O P- Ω h-¹ LQ rr 3 O X fi TJ 3 Φ CO h-¹ O CO 3 rt rt h-¹ if 3 3 Hi 3 rt LQ Φ Hi 0 Φ •

0 ED φ P- rt ED P- • 0 φ Hi Φ Φ -¹ 3 if P- P- TJ LQ SD P- C _^. rt fi α H 3 3 ED Φ O 0 3 > a 3 fi 3 Ω > Hi 0 ED Φ ] Ω Ω P- Ω c 1 P- rt ED O rr rt LQ CD CQ 3 < Ω φ P- rt 0 Ω 3 s; CD if Φ 3 Ω rt CQ P- M ^ 3 0

Φ Φ to O Φ Ω CQ 3 3 ED 3 Ω X CQ Φ CQ LQ Ω Φ P- 3 n C H LQ fi fi tr 0 rt Ω SD 3 0 X rt LQ rt Ω 0 0 Hj P- Ω tr ED 0 Hi 3 LQ 0 o CO cr ED

Φ CO Q- Φ Ω 0 P- rt Hj P- Φ P- Φ Hi Hi Φ π Hj CD 0 3 0 rt Hj CQ LQ c 1 Hi Φ rt O 0 φ P- P- ED TJ P- fi h-¹ fi rt o Hi fi CQ LQ Φ Ω & Hi if fi SD Φ o Hi 0 SD

Ω Hi <! 3 SD TJ rt ED 0 P- h-¹ 0 3 3 P- Ω 0 Φ Hi Si φ P- Hi α ~ ≥; 0 Hj SD cr

Hj rt P- LQ rt Hj Φ rt 3 3 Φ C CO 3 if P- 3 Φ s Hi 3 Hi 3 Hi 3 cr SD

P- Ω Φ Φ fi rt LQ O rt ED LQ ED c CQ Φ ED co 0 hti LQ 0 P- -¹ CQ tr ED Φ CO fi O Φ P- if Hi SD Hi rt SD 3 3 3 0 3 Ω ED 0 Ω r-4 Φ φ

Φ Hj Φ Φ S. Hj O rt P- rs Φ φ rt ED P- Φ Hi fi S rt 3 rt o 3 rr d SD M

Φ 3 TJ rs P- 3 SD 0 3 LQ CD fi 0 Ω 0 CO Φ 3 P- CQ rt 0 fi Si LQ SD ^ TJ X rt P-

ED Φ SD rt rt P- P- Φ rt 3 TJ ED CD C 3 P- φ C- cr ED SD 0 3

P- ^ Ω rr rr if fi SD rt ED 3 o <! ^ Φ Φ ^ 3 Ω SD 0 CD Hl - SD Hi 3 3

3 SD rt rt rt ED 3 tr fi < Hi P- Φ Hi CQ Ω o α rr Hi Hj 3 Hi LQ Hi 0 φ TJ SD SD

Hi ED Φ rr O Ω CQ Φ Φ Φ Ω rt Ω P- Hi Φ Φ 0 Φ Φ $. Φ 0 Hi CQ h-¹ CO rt C tr Hi Φ ED X Ω SD iQ 3 ED Φ 3 Hj CD • Hi • rt SD Hj if • Hi Φ φ Ω Ω rr 0 Hj 3 P- LQ Hi CO ED C rt ED ED Φ h-¹ ED LQ P-¹ n rr CQ Φ P- ω «.. CQ Φ φ

Φ ≤ rt Φ Ω Si Hj Φ TJ Hj SD P- O h 3 ^<< Φ P- n 0 Φ TJ 3 Ω rα ^ P- Hi Hj

P- rr tr o 0 Φ Φ rt rt 0 Ω O 0 "< TJ 3 X c φ rt rr 0 0 3 ω 0 rr rt

TJ 3 Φ ED ED TJ f- 3 Ω Φ 3 Hi Hj rt to 0 cr Φ ED Hi Hi Ω ≤ hi TJ P- Hi ED ED

Hj LQ Hj Ω Ω SD rs rt Ξ φ if hi ED Hj Φ ϋ 3 P- 0 rt -> P- Φ Φ LQ P- P-

Φ Ω X P- rt P- ED P- CO φ TJ Φ P- C fi rt • TJ Φ 3 - SD CD <! ED P- LΠ Φ 3 O P- Ω O LQ 3 rt 0 h-¹ O H 3 Hj Hi CQ tr Φ ED CD Hi rt ³ . ,

3 φ 3 Hi - 3 P¹

Φ 3 0 Hi Hj ED Φ Hi Hi if _^ Φ Φ Φ xQ if Φ O LQ ED Hj P- Ω rt ι_ι LΠ

3 TJ 3 fi 0 rt Hj ω o rt φ CQ ED . Hj C h-¹ Ω CO -2 O ED C 3 Φ W 0 if ED rt h-¹ TJ P- c P- 3 SD s: rt Hj $, ED Φ CO φ SD φ 0 Φ rt P- t SD ϋ fi Φ 3 φ Hj 3 3 0 P- CO if Φ ED 3 Ω 3 TJ rt 0 ≤ ^ fi LQ φ rt 3 Ω P- LQ

SD 3 P- LQ fi 3 fi Φ SD Hi Φ Ω rt Φ Ω Φ fi TJ Hi Φ 3 rr fi Ω 1 3 SD C-

TJ φ CQ Ξ TJ Φ rt 0 P- Ω 0 ED c Φ 3 CQ Ω P- rr H LQ TJ ED

TJ 3 Φ rt P- 0 r TJ Hi fi P- if Hi 3 rt 3 Hi rt rt Hi P] SD 0 CD c P- s: TJ LQ h-¹ rt 0 3 Hi Φ ED Φ Φ h-¹ 0 0 ϋ LQ ~ Hi O ED Φ 0 P- o O ED fi m 3 Hi -> φ

P- SD rr Hj rt CQ <! ^ Hj P- f- Hj Hj 3 3 Hi X 3 P- P- ^ Φ Hi 0 P- _^

Ω rt ED rt SD CQ Φ rt Φ P- 3 SD rt CQ if rt φ P- fi 3 CO 1 CO 0 Hj Φ

SD P- Hj if SD P- Φ 3 Ω tr rr 3 LQ if P- CO to CQ ω CQ a LQ ∞ Φ HJ 3 fi P- rt 0 fi Φ 3 P- rs Hi rt Φ Φ SD SD TJ φ 0 c n Ω CQ SD LQ ED 3 » -. O rt

P- 3 Ξ SD Ei 3 SD Hj rt SD 3 Ω Hi r S P- Hi 0 rt 0

0 SD rt CQ rt rt SD SD fi 0 rt TJ rr h-¹ Φ * φ fi Ω TJ 0 rt rf^ M Hj SD Hj P-

3 0 Hj X TJ if if P- Ω tr ≤ CQ rt Hj 0 P- Φ s; 0 if Hj 1

Hi Φ α ED Hj CD τ φ SD Φ to 0 Ω h-¹ SD c SD Φ φ Hi CO rs 3 Φ Ω SD 3 SD cr Ω Q- Φ SD

"" Φ £i rt Ω 3 0 Φ Hi P- 3 Hi CD Ω LQ ^•» CO rr

CQ X Hi π TJ cr TJ ^ P- TJ 0

ED rt Φ rt ^ 3 φ rt Hi o SD Hj Φ P- TJ rt ³^ rt M TJ Hi

3 ED 0 H Φ Ω LQ 0 fi rt - SD 3 rr Φ ED ED 3 Hi P- rt 3 Φ pd P- rt

^•^ 3 Hi 0 Hj Hj Hi Hi P- 0 tr 3 P- rt Φ Φ Φ Hi ED SD CO IQ Ω P- ^ 0 Ω P- Φ

Hj 3 Φ 0 rs £ h-¹ φ rs 3 <! fi Φ 3 Ω Φ • Ω M 3 1 Ω 3

0 TJ 3 Φ c SD LQ TJ rr ^ rt P- rt CQ P- P- rt CO C- CD α SD | ED

Hi 0 SD £ 3 3 Hj P- if ED 3 - Ω CQ φ Si t cr n 3 fl cr <

TJ rt P- Si TJ r 0 Ω cr 0 <! τ3 Φ T s Hi P- o P- _^ ED rt rt rt rt P- SD 0 rr Φ φ Φ o . -¹ CO 3 Φ Hl Ω φ rr Φ if rr CQ cr rt 3 Hi ED LQ Hi P- tr C

Φ hi Φ Φ 1 SD 1 0 ^ 0 Φ P- rs Hi Hi fi 1

Brief Description of the Drawings

Other features and advantages of the present invention will become apparent from the following detailed de- scription of a presently preferred embodiment, with reference to the accompanying drawings .

Fig. 1 is a screen view showing a way of presenting interpretation candidates according to the prior art.

Fig. 2 is a flow chart of a method according to the invention.

Fig. 3 is a schematic view of a device according to the invention with a handwritten pattern entered in an input area of the device.

Fig. 4 is a schematic view of the device in Fig. 2 with a best interpretation presented in a presentation area of the device.

Fig. 5 is a schematic view of the device in Fig. 2 with alternative interpretations presented in a presentation area of the device. Fig. 6 is a screen view showing a way of masking the presentation of patterns according to the present invention.

Detailed Description of a Presently Preferred Embodiment Fig. 1 shows a screen view according to the prior art. A box, 98, shows a number of candidates for input to be made, among these "ko" hiragana and "ko" katakana.

Referring to Fig. 2, a method according to the invention for presentation of a recognition of a handwrit- ten pattern will be described. First, a user enters a handwritten pattern, step 2. The user enters the handwritten pattern in an input area on a pressure-sensitive screen. The user uses a pen to apply pressure on the screen and write the pattern. As the user moves the pen across the screen, the parts on the screen that have been exposed to pressure are highlighted. Thus, the user can see what he writes.

rr C > CD P] ED ED rt TJ Hj TJ ≤ rt P- P- rt ED TJ TJ TJ CD TJ Hi rr rt rt rt rt fi rt 3 TJ H

ED CO P- rr to 3 P- Hi Φ Hj P- P- 3 3 P- Hi Hi Hi Ω SD Φ SD Φ SD rr Φ ED P- P- ED rr

3 φ CQ N Φ O Φ Φ h-¹ 0 rt rt <! Hi φ Φ φ Hi rt Hi 3 Hj rt Φ hj rt O N rt Φ fi Hj 0 Φ 3 rt ED 3 CO φ CO P¹ 3 Φ Φ Φ φ O O CQ Φ rt Φ fi 3 P- 3 ED 3 Φ rt

Ξ - rr Φ 3 CO • Hi Hj & Φ Φ Φ Φ Φ Hi ≤ «• 0 rr • tr ED fi Φ CD

Hi s Ω SD Φ rt P- 3 rt Φ £ϋ TJ TJ H P- C 3 3 3 3 a H Φ Hj 3 SD SD h-¹ - Hi rt S

P- rr O rt CO rt φ 3 rt Φ 0- -¹ H Hi Hj Hi 3 Φ rt rt rt rr 3 3 P- CQ 3 H CD 3 Φ Φ rt φ c rr rr Ω Hi Φ O rr Φ Φ rt O SD SD SD Φ • Ω rt if • fi rr φ ≤ CO TJ X rt 3 P¹ Φ rt P- 0 3 0 fi 0 Φ rt rt rt Φ rt rt rt rt CO 3 Φ rt P- Φ SD rt rt

Φ fi if CQ Hi SD Hj rt rt SD SD rr Hj P- P- P- rt Φ Ω H H{ 0 Φ

^ H o -

3 rt Hj φ Hj rt fi P- rr rr CQ TJ rt rt Φ T cr O O 0 Φ TJ 3 tr rr P- Hi Hi TJ rr Hi rr Ω Φ Ω φ P- Φ 3 Φ Φ rr Hi P- P- Hj c 3 3 3 TJ rt SD Φ rt Φ φ rt

TJ Φ if Λ tr 0 Ω <! Hj 0 Φ 0 0 c φ rt rr rt TJ rt rt Ω Hi s: σi 3 fi rr

ED SD c Φ Hi rt Φ ED TJ TJ ≤ CQ 3 3 CQ rt rt 0 0 ED CD Φ rt fu rr σ Φ 0 Φ if • Φ Φ rt c 3 φ ω Hj rt SD SD Φ O ω Φ SD 0 Hi Hi Hi • Φ rt Φ Φ 3 LQ Hi Φ rt rt CD LQ CO rt Φ hj P- O CO rt rt CD 3 H rt 3 Φ cr Hi rt CO 3 Φ Hi H rt Φ rr

Φ Φ Φ rt Ω Φ 3 3 rt rt rt Ξ SD P- rt rt SD H Φ 3 Φ Hi rt TJ P- Hi Φ rr rr Ω CD

Hi Hj P- rt Ω rr rt SD Φ Φ Ω SD P- hj SD 0 Hi if if rr CO O Hj Φ SD rt Φ P- Φ Φ rt 3

3 rt tr 3 0 Φ SD -¹ Hi hi ED rt Φ Ω 3 0 Φ Φ rt Φ rt 3 Ω P- rt P- 3 3 P- ti if rr c rt Hi LQ Hj X 3 3 3 P- P" rt CQ Hi tr rt • 0 3 rt 0 Ω Hi fi 3 ≤ rr ED Φ rt Φ φ 3 TJ Φ Φ • Ω 0 TJ P- cr rr ED cr P- rr LQ rt Φ 3 Φ rt Φ Φ LQ H|

Φ CD rt hj Ω P- Hj Hi P- Φ 3 rt Hj < P- Hi Φ ED rt Φ 3 SD H 3 Φ H| if o rt P-

P- 0 TJ O rt Φ C m co rr Φ t CD Φ CO 3 O rt rt rr P- Hi 3 Hj TJ φ 0 Φ fi rt

Ω SD 3 3 Hj LQ P- rt TJ Hi rr 0 Φ CQ rt & rt fi O rt Φ Φ rt TJ Φ SD LQ Ω P- rt

SD Ω rt Φ 3 O SD O Φ ϋ tr Hi 3 Φ Φ TJ c s: <! Hi ED P- Hi SD rt rt fi 3 rt LQ Φ

3 Ω Φ P- rt P- 3 rt SD Hi φ c 3 CQ Hj φ P- hj φ P- TJ Hj ED O Φ 3 C rt φ P- Φ P- 3

Φ Hj CQ ED rt P- 3 3 SD rt rt Hi rt Φ CQ 3 P- Hj 3 Hj Φ 3 rt ϋ Hj Φ rt rt fi rt

Ω TJ TJ rt P- 0 0 ED h-¹ Φ rt rr Φ Φ rt CO rt rt rt h-¹ rt Φ rt CD 3 Hj Φ P- P- T

0 rt Hj ED P- 0 hh 3 Φ rt rt rt 0 Φ TJ fi rr Φ P- Φ rt ED Φ rt P¹ Φ Hi rt CD CO 3 Ω 0 rr rsi fi) P>

3 φ Φ LQ 0 3 μQ φ Φ 3 Φ 3 3 Hi Φ TJ Hj ED φ Hi P- P- Φ CQ rt 3 SD Φ rt ι rt fi rt ED 3 rt P- C rt HJ fi SD ED r LQ TJ 3 CQ TJ rt CQ 3 3 0 < ED Φ 3 CD rt

P- SD P- P- rr to CD rr 3 P-¹ Ω CO cr Φ Hi Hj P- CO SD α 3 Φ rt fi P- Φ

3 rt rt 3 s£ CQ Φ SD SD ED M rt Φ rt f- Si TJ φ TJ rt Φ 0 rt CO Hj if O CQ ≤ rt Hi

C rr P- ED TJ 3 rt 3 Hi Φ Φ rt Hj rt ED rr rr 3 SD P- P- ED φ TJ Hj rr 3

Φ Φ 0 TJ CD T if Hj CD P- fi Hi rt TJ rt Φ SD rt Φ SD ^J < rt CQ P¹ CO Hi ED TJ P- Φ

3 Hj Hi SD Φ TJ rt < rt 3 rr 0 CQ rt rt rt P- P- Φ 0 rt P- rt Φ rt P- rt Hi Φ TJ Φ 3 CD £D if Φ rt rr SD Φ P¹ 3 Φ P- Φ P- P- CD X rt ED 3 rt Hi rt Φ CQ

0 Φ 0 CQ Hj CQ fi CQ Ω Φ rr Φ rt o 3 0 hi 3 0 φ P- tr rr -> P- fi Φ Hi Φ 3

Ω Hi Φ Φ Φ ≤ Φ Φ P- Φ P- tr . rt 3 3 TJ 3 TJ 3 Φ Φ rt 3 Hi 0 3 rt

Φ 0 3 CD 3 Hj tr 3 Ω <! Φ rt ED c Hi rt rt Φ rt ED 3 Hi Φ φ

3 LQ rt rt Φ rt P- 0 Φ rt E- SD φ O H rr rt P- rr P- Φ if Φ 3 Hi Hj Φ 3 TJ Hj rt rt 3 rr Φ 3 Φ rt Hi CO Φ fl 3 rt rr Φ P- CO CD co CO φ Hi o Φ 3 hi 3 P- φ SD Φ Φ

Φ P- Φ fi rt fi rt P- rt Hi Φ Ω P- Φ 0 P- CD Φ TJ CD Hi SD TJ ED co fi rt Si Ω

Hi rt - Φ Φ rt rt TJ Hi φ 3 P- ED 3 3 Hi Hj TJ 3 rr Hi rt Φ rt Hi rt rt rt

P- TJ fi P- 3 rr P- H| h-¹ rt 3 ED ^J £- Φ Φ Hj r SD φ Hi P- Φ Ω Ω P- Φ rr Φ

SD 0 CD CD 3 P- Φ 3 Φ Ξ Φ rt P" rt o h-¹ TJ SD Φ Φ 3 rt CD φ <J rt rr 0 3 Hj SD fi

3 rt 0 P- TJ co rt rt P- if Hj Φ rt Φ Hi rt \-> . CQ fi CD 3 Φ ED P- 3 3 3

3 rt 3 rt SD D Φ SD c T Hj Φ Hi SD SD Φ s: rt P- Ω rt 3 TJ ED fi

Φ 0 Φ rt rr rt SD Ω Hi rt h-¹ rt Hj TJ Hj 3 SD 3 Ω H 3 0 Hj P- X Φ P- P- LQ SD P- 5^» CQ

Hi Hj rr CO Φ rt Ω Hi TJ P- rt Φ Hj 3 ED P> Φ Φ if rt 3 P- 0 φ 3 0 Hj Ω o Hi rt

3 SD rt Φ Ω φ Hi O rr O rt Φ ED rt rt 0 Si c Φ rt 3 T rt 3 TJ Φ 0 P- φ if rt « rt Φ CO hj φ φ Φ 3 ED 3 ED rt rt P- Φ C O fi rt rt CO rt ED Φ SD fi 3 P, rt TJ

SD tr TJ ED 3 TJ 3 rt O < rt SD P- <i Hi CO if ~ rr Φ rr rt Hi 0 rt <! Φ rt

3 Φ rt 3 rt SD Φ P- P- <: Φ 3 "< P- Φ 3 SD φ TJ Hi rt Φ Ω Φ ^ fi rr ∞ Φ Φ CD 0 Φ ^ rt 3 Hi Hj 0 3 0 3 Φ Si Hi rt 3 SD if Φ Φ LQ Hi Φ 0 φ

written pattern in the input area and the method is returned to step 2. However, several patterns could be entered in the input area. The user can then enter several patterns before he corrects the interpretations of the patterns.

When a pattern is recognized it is also presented in a second presentation area for presenting the whole text that has been entered. This second presentation area presents the recognized patterns in a small size. Thus, the second presentation area could present a larger amount of entered patterns. This presentation area could be scrolled to show earlier entered patterns.

In Figs 3-5, a device according to the invention for recognition of a handwritten pattern is shown during dif- ferent steps of the method. The device 20 will be described in relation to Chinese character recognition. The device 20 comprises a pressure-sensitive screen 22. The screen 22 presents a user interface to a user of the device 20. The device 20 further comprises a database of reference patterns and means for comparing handwritten patterns to the reference patterns in order to recognize the handwritten patterns. Thus, the device 20 comprises a central processing unit, which handles the recognition of the handwritten patterns and input and output through the user interface.

The user interface comprises an input area 24, where the user can enter handwritten patterns, and a presentation area 26, where interpretations of the handwritten patterns are presented. The presentation area 26 and the input area 24 overlap each other. Thus, a user could keep his eyes focussed on the same place of the screen 22 when entering the pattern and studying the interpretation of the pattern. The user interface also comprises a second presentation area 28, where entered text is presented and a large amount of patterns could be presented simultaneously. The input area 24 comprises guidance lines 30, which are presented to the user for guiding him where to enter a handwritten pattern. The guidance lines 30 form principal entering areas in the form of squares 32 for entering one character in each square 32. However, the user is allowed to enter parts of the character outside the square 32. This corresponds to the way a user normally writes Chinese characters. The guidance lines 30 are green to further imitate the appearance of a normal Chinese writ- ing paper.

Referring to Fig. 3, the device is shown during steps 2 and 4 of the method. The user enters a handwritten pattern 34 in a square 32 in the input area 24. The entered pattern 34 is highlighted on the screen 22 so that the user can see the pattern 34 he enters.

The entered pattern 34 will then be recognized by the device 20. Referring to Fig. 4, the device 20 is shown during step 8 of the method. The best interpretation 36 of the pattern is presented in the square 32, where the pattern was entered. In the lower, right corner of the square 32 a small tip 38 is presented. This indicates that alternative interpretations could be presented if the best interpretation 36 is incorrect.

If the user clicks on the tip 38, several alterna- tive interpretations 40 are presented as shown in Fig. 5 corresponding to step 10 of the method. The alternative interpretations 40 are presented in the square 32, where the pattern was entered. The user could then click on any of the alternatives 40, whereby the clicked alternative is selected as the correct recognition of the pattern. A cancel button 42 is also presented with the alternatives 40. If the cancel button 42 is activated, the device 20 concludes that the correct interpretation was not presented. The input square 32 is then emptied and the user could re-enter the pattern.

An alternative 40 may be presented at the same time as the best interpretation 36. For example, a best inter- pretation 36 may be presented in the center of the presentation area 26, whereas alternatives 40 are presented in smaller size along the edges of the presentation area 26. Then, one or more alternatives 40 may be presented at the same time as the best interpretation 36. For enabling further alternatives 40 to be presented, this may be combined with the possibility to request for alternative interpretations 40.

Fig. 6 shows a screen view according to the present invention. Here the different types of characters are marked with different shading, 100.

In a preferred embodiment the method according to the invention is implemented on a handheld PDA device having a color screen. The device is adapted as to allow presentation of patterns on the screen. The patterns will comprise characters in normal use in the Japanese writing system; Arabic numerals, Latin letters, hiragana, katakana, Japanese kanji and other symbols.

Masking will be provided as follows. Latin letters and other symbols will be displayed black on a white background, numerals black on a grey background, hiragana black on a green background, katakana black on a blue background, and finally Japanese kanji black on a yellow background. Thus, a user of the device will be able to immediately identify the particular type of character. The presented characters are written along horizontal lines, with similar spacing between the characters; all the pattern backgrounds being rectangular and having the same area. When the masking is used, the user will be able to select between the candidates and may easily distinguish between similar characters of different types. Even after selection of a correct candidate, the type of characters already written may still be indicated by the applied masking. If the user should want to, he can change the type of masking applied to the various types of characters. It should be emphasized that the preferred embodiments described herein is in no way limiting and that many alternative embodiments are possible within the scope of protection defined by the appended claims. For example, the request button or tip could be presented in several other ways. Alternatively, presentation of alternative interpretations may be requested by drawing a specific gesture in the input area.

Further, there may be a possibility of requesting suggestions for the following pattern to be entered. In this way, the user does not need to enter the pattern at all by handwriting. Instead, the device suggests a pattern in accordance with the earlier entered and recognized patterns. This suggestion may be based on bigram statistics, i.e. statistics of the probability that a specific pattern is followed by another specific pattern. The device may in this way return a whole word or the ending of a word as a suggestion. This may also be used for changing the interpretation of a pattern that pre- cedes the latest entered pattern. In this way, the user will not have to re-enter a pattern that has incorrectly been accepted as a correct interpretation.

The handwritten pattern could be a symbol representing a formatting or editing function. Thus, the pattern could represent space, delete, return, caps lock etc. An interpretation of a handwritten pattern could be cancelled through the cancel button, when no alternative was correct. However, the delete symbol could be used for deleting a character, for which the interpretation has been accepted.

Claims

1. A method for presenting a recognized handwritten pattern, comprising the steps of: detecting a handwritten pattern that is entered by a user on an input area on a screen, recognizing the detected handwritten pattern, said step of recognizing returning a best interpretation of the handwritten pattern and at least one alternative in- terpretation of the handwritten pattern, presenting the best interpretation in a presentation area on the screen, said presentation area overlapping the input area, and presenting the at least one alternative interpreta- tion in the presentation area.

2. The method according to claim 1, wherein the at least one alternative interpretation is presented at the same time as the best interpretation.

3. The method according to claim 2, wherein the best interpretation is presented in a larger scale than the at least one alternative interpretation.

4. The method according to claim 2 or 3 , wherein the at least one alternative interpretation is presented at the same time as the best interpretation only where distinguishing between the best interpretation and the at least one alternative interpretation during the step of recognizing is difficult.

5. The method according to claim 1, wherein the step of presenting the at least one alternative presentation is made at the request of a user.

6. The method according to claim 5, wherein the step of presenting the alternative interpretation replaces the presented best interpretation.

7. The method according to any one of the preceding claims, wherein the steps of presenting interpretations replace the entered handwritten pattern.

8. The method according to any one of the preceding claims, further comprising the step of presenting at least one suggestion for a pattern that is to follow or precede the recognized handwritten pattern.

9. The method according to claim 8, wherein several suggestions are determined through bigram statistics, the suggestions being returned as alternative interpretations .

10. The method according to any one of the preceding claims, wherein the step of recognizing returns several alternative interpretations and the step of presenting alternative interpretations presents all the returned alternative interpretations.

11. The method according to any one of the preceding claims, further comprising the step of presenting guidance lines in the input area for guiding a user where to enter a pattern, said guidance lines defining a principal entering area, which covers only a part of the input area for allowing a user to enter parts of the pattern outside the area defined by the guidance lines.

12. The method according to claim 11, wherein the step of presenting guidance lines imitates the appearance of a writing paper.

13. The method according to any one of the preceding claims, wherein the steps of presenting comprises the step of presenting a pattern on a pattern background visible on a part of said presentation area of said screen, said pattern background being associated with said pattern, wherein a combination of said interpretation pattern with said associated pattern background is presented in a masked form, the masking of said combination being selected according to the type of pattern pre- sented.

14. The method according to claim 13, wherein each presented pattern is associated with a pattern background, each combination of each said pattern and each said associated pattern background being masked according to the type of each said pattern.

15. The method according to claim 13 or 14, wherein presented patterns are displayed along horizontal or ver- tical lines.

16. The method according to any one of claims 13-15, wherein the sizes of the areas of the associated backgrounds are equal or different.

17. The method according to any one of claims 13-16, comprising the steps of: a) identifying the type of pattern to be presented; b) selecting the type of masking corresponding to the type of the pattern; c) presenting the combination of said pattern with said associated pattern background on said screen while applying the appropriate masking for said combination.

18. The method according to any one of claims 13-18, wherein a viewer of a presented pattern may choose the type of masking associated with the type of said pattern.

19. The method according to any one of claims 13-18, wherein said masking comprises changing the appearance of said combination.

20. The method according to any one of claims 13-19, wherein said masking comprises enhancing or lowering the contrast between the pattern and the associated pattern background.

21. The method according to any one of claims 13-20, wherein said masking comprises changing said associated pattern background, the change being selected among the group consisting of change of color, shading and hatch- ing.

22. The method according to any one of claims 13-21, wherein said masking comprises changing said pattern, said change being selected among the group consisting of change of color, shading and hatching.

23. The method according to any one of claims 13-22, wherein the type associated with each pattern is user definable .

24. The method according to any one of claims 13-23, wherein said handwritten pattern and the presented patterns comprise a character.

25. The method according to claim 24, wherein said character is selected among the group consisting of Chinese characters, Japanese kanji , hiragana, katakana, Latin letters, Greek letters, Arabic numerals, and punctuation marks.

26. The method according to claim 24 or 25, wherein said masking is selected according to the type of said character, said type being selected among the group consisting of the types Chinese characters, Japanese kanji , hiragana, katakana, Latin letters, Greek letters, Arabic numerals, and punctuation marks.

27. The method according to any of claims 24-26, wherein said masking comprises changing the font or the font style of said character.

28. A device for presenting a pattern in a presentation area of a screen, according to the method according to any of the preceding claims.

29. A device for recognition of a handwritten pat- tern, said device comprising a screen for user interaction, which screen comprises an input area, which is sensitive to handwriting, and a presentation area, which is arranged to present a best interpretation of a pattern entered in the input area and which is arranged to present at least one alternative interpretation of the entered pattern, said presentation area overlapping the input area.

30. The device according to claim 29, further comprising means for requesting the presentation of the at least one alternative interpretation of the entered pattern.

31. The device according to claim 30, wherein the presentation area is arranged to present the alternative interpretation at the request of a user through the means for requesting.

32. The device according to any one of claims 29-31, wherein the screen further comprises guidance lines, that are presented in the input area for guiding a user where to enter a pattern, said guidance lines defining a principal entering area, which covers only a part of the input area for allowing a user to enter parts of the pattern outside the area defined by the guidance lines.

33. The device according to claim 32, wherein the guidance lines imitate the appearance of a writing paper.

34. The device according to any one of claims 29-33, wherein said screen allows presentation of a pattern on a pattern background, said pattern background being associated with said pattern, and wherein the screen is adapted to present the combination of said pattern with said associated pattern background in a masked form, the masking being selectable according to the type of pattern presented.