Input of symbols

Details Input of symbols Input of symbols

2000-09-15

2004-11-23

Horabik, Michael (Department: 2635)

Coded data generation or conversion

Bodily actuated code generator

Including keyboard or keypad

C341S022000, C345S171000, C379S368000

Reexamination Certificate

active

06822585

ABSTRACT:

FIELD OF THE INVENTION
The invention relates to inputting symbols from a keyboard or a keypad and is particularly, but not exclusively, related to inputting symbols which are not part of the Latin alphabet. In one embodiment the invention is used in the input of characters from character-based languages, such as Chinese hanzi characters and Japanese kanji characters.
BACKGROUND OF THE INVENTION
Using a keyboard to input characters (also referred to as ideograms) from character-based languages such as Chinese has presented difficulties for some time. There are more than 20 000 Chinese characters and of them about 5 000 to 12 000 are currently commonly used. Therefore, it is not practical to provide a keyboard having a one-to-one correspondence between individual keys and individual characters.
In current methods of inputting Chinese characters into electronic devices having a keyboard (for example a computer), it is known to employ indirect input by describing characteristics of a Chinese character and then selecting a particular Chinese character prompted in a candidate list which is presented to a user. This prompting is performed by software specially written for input of ideogram characters which is referred to as a Front End Processor (FEP) or an Input Method Editor (IME). An FEP interprets an input string from the user and prompts to the user a candidate list of the Chinese character(s) which match the input string or description. The user can then select the correct candidate (if it is shown) from the list and it is entered into a display as the selected character. The candidate can be more than one character. It may be a phrase.
Different ways of describing characters provide the bases of different Chinese input methods. Characters are either described phonetically in which Chinese characters are inputted by describing the associated pronunciation or they are described in terms of character shape in which Chinese characters are inputted by describing the graphical construction or shape of the character. In the People's Republic of China, the method used to describe pronunciation is Pinyin, which literally means “spelling the pronunciation”. This is a phonetic representation of Chinese characters by a Latin alphabet in conjunction with accent marks. Another phonetic description approach is Zhuyin (Bopomofo). This is a phonetic representation of Chinese characters by 37 specific Bopomofo symbols and tone marks.
Because most of the existing Chinese input methods were originally designed for PC keyboards, the number of the basic input symbols or input codes normally matches the number of keys present on a standard QWERTY format keyboard. The table below gives the number of keys required for some of the more popular Chinese input methods.
Input method
Description
Number of keys required
Pinyin
Pronunciation
26 + 4 (for tones)
Wubizixin
Character shape
25
Bopomofo
Pronunciation
37 + 5 (for tones)
Changjei
Character shape
25
Simple five
Character shape
 5
stroke
If a character input method requires more basic input symbols than there are number of keys on a keypad, the first step of inputting the description will encounter a bottleneck. This is caused by more than one symbol being associated with one key which results in repeat or multiple keystrokes being required to input particular symbols.
The problems presented by keyboard input of characters are particularly acute in relation to inputting characters into mobile communication terminals such as mobile phones. This is because of the restricted number of keys (often less than twenty) present in the keypads of such terminals. Since the number of symbols required is often greater than twenty, this can cause the bottleneck described above. Furthermore, since the displays of such terminal are usually small, this can present further difficulties, especially if there needs to be interaction between the terminal and a user of the terminal during the input of symbols and characters.
In the table above, the simple five stroke method is referred to. A stroke is the smallest graphic element to construct a Chinese character and is a complete stroke by a writing tool without lifting it from a writing surface. There are five basic strokes. In the case of a mobile phone, the simple five stroke input method is the one whose input codes can be easily mapped to a phone keypad. However, it is the slowest method to use.
Pinyin is a popular method for inputting Chinese characters into electronic devices because it uses symbols from the Latin alphabet to describe the characters and there are only 413 pronunciations (without using tone marks) for the 6763 commonly used characters in the national standard of the People's Republic of China, GB2312-80. This means Pinyin has only 413 words in its vocabulary which need to be described.
An example of Pinyin will now be given. If a user wants to input the characters meaning “middle” or “centre”, he uses letters or symbols from the Latin alphabet to enter the Pinyin pronunciation “zhong”. The FEP receives this input string and identifies a number of characters which have this pronounciation. These characters or candidates are presented to the user in the from of a candidate list. The Latin letters input by the user and the candidate list are shown in
FIG. 1
which represents part of a user interface. This represents a typical situation in which there is more than one candidate available for a given input string. The average number of candidates matching a given input string of an input method is called the Input Coding Redundancy Rate (ICRR). The higher the ICRR, the longer the candidate list a user will receive for an input string, and so the greater number of candidates the user has to scroll through in order to find the correct character. High ICRRs slow down the speed at which characters can be input.
Phone keypads generally have a key layout corresponding to that shown in
FIG. 2. A
set of symbols (or an alphabet) is assigned (or mapped) to most or all of the keys. For any particular key its alphabet of assigned symbols forms a queue or loop. Within a predefined time-out period, a user presses the key an appropriate number of times sequentially to select a desired symbol in the alphabet. The symbol is then indicated in a display. The symbol is entered into the display if the time-out period expires or if a different key is pressed.
It is time-consuming to input strings of symbols into mobile phones and so methods have been developed to reduce the number of keystrokes that are required. In a method commonly known as T9 provided by Tegic Communications, Inc., input occurs as “one alphabet one key stroke”. A user identifies the key on which a desired symbol is present and presses that key once. A particular alphabet of three or four symbols is typically associated with that key. This method has been adapted to use the Pinyin system to input Chinese characters. An example will now be given. If a user wants to input the Pinyin string “gao”, he needs to press the keys 4, 2, 6 on the keypad. The method identifies the Pinyin strings which are permissible and can be formed by the alphabets from keystrokes 4, 2, 6 and displays all of them to the user. In this example the permissible Pinyin strings are “gan”, “gao”, “han”, and “hao”. All characters which match the permissible Pinyin strings are then indicated as candidates.
A disadvantage of T9 is that a long candidate list is often generated for a given input. This problem becomes worse as the input string becomes shorter. For Chinese input, T9 presents a list of all Chinese characters as candidates if they match any of the possible combinations for the keys which have been pressed. For example, if keys 7 and 4 are pressed, all characters with Pinyin of “pi”, “qi”, “ri”, “si” are indicated, which makes a very long candidate list.
T9 has other disadvantages. It does not give clear feedback in response to user input. This is usually desirable in Chinese input because it is an interactive process in which the user should be able to cor

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