ERRONEOUS KEYBOARD ENTRY CORRECTION METHOD

Abstract: A method of correcting an input to a device, which a user interacts with by a series of touch actions, including the step of detecting each touch action, measuring the time interval between one or more touch actions, generating a first output in dependence on the one or more touch actions, checking the first output against a table of allowed outputs, and generating a revised output if the first output is or might be in error and if the time interval satisfies a predetermined time interval criterion.

Description: Erroneous keyboard entry correction method Field of the invention This invention relates to a method for correcting erroneous keyboard entries, such as result in misspellings or other kinds of input errors. Description of the Prior Art Sophisticated word processing programs such as Microsoft Word include advanced spell check programs which can compare words input to a computer using a conventional QWERTY keyboard against words in a dictionary stored in the computer. Touch screen keyboards, such as are used in personal organisers and some communicators, are particularly prone to mis-hits because of the small size of the keyboard and the absence of discrete keys. Spell check programs are also found in hand held, self contained units, such as those from Franklin Computer Corporation. Spell-check programs have been the subject of intense scrutiny for several decades and many different approaches have been devised for effective spell-checking. Reference, for example, may be made to US 5248536 in the name of Franklin Electronic Publishers, Inc. which discloses a spell-check program which includes comparing an input word to a dictionary using phonetic comparison, typographic comparison, vowel and consonant typographic comparison and consonant phonetic comparison. The exact form of comparison which is undertaken in contemporary spell check programs involves sophisticated pattern matching algorithms which are disclosed in the literature. Statement of the Present Invention In a first aspect of the present invention, there is provided a method of correcting an input to a device, which a user interacts with by a series of touch actions, comprising the steps of: (a) detecting each touch action; (b) measuring the time interval between one or more touch actions; (c) generating a first output in dependence on the one or more touch actions; (d) checking the first output against a table of allowed outputs; and (e) generating a revised output if the first output is or might be in error and if the time interval satisfies a predetermined time interval criterion. Hence the present invention is predicated on the insight that input errors are often revealed by closely monitoring the timing of the associated touch inputs, such as the key up and key down actions. For example, the device may be a physical or touch screen keyboard so that a touch action might be touching a first letter key and a subsequent touch action might be releasing the first letter key or touching, within a predetermined time interval, a second letter key; the first output then relates to the generation of a word using the letters in the key touch sequence, a dictionary look up process then indicates that the generated word is not an allowed word and the revised output is associated with transposing the order of the first and second letter keys to generate a word which is present in the look up dictionary. The touch action could also be touching or releasing the shift key, followed by another touch action which occurs after the shift key has been released, so that there is a time interval between releasing the shift key and hitting the next key. The revised output is then that output which would have been generated if the next touch action had in fact occurred whilst the shift key had been selected. This corrects the frequently occurring input error of inadvertently releasing the shift key before hitting the key which should be shifted. For the purposes of this specification, a shift key is any modifier key, such as the Ctrl, Alt and Shift keys on a PC keyboard. The revised output need not necessarily be an automatically corrected version of the input; it may for example, be a warning message or some other action. The predetermined time interval threshold may be fixed or it may vary as a function of the time interval between one or more touch actions. In the latter case, the normal interval between keystrokes is measured and the time interval between touch actions which is a predetermined amount less than the average time interval, constitutes the threshold below which a revised output may be generated. Hence, a system using this method may accord a relatively slow typist a much longer time interval threshold than a very rapid typist. In two other aspects of the invention, there is provided a computing device and a computer program operable to perform the above methods. Detailed Description In a preferred embodiment, the correction of erroneous input on keyboard devices is based on knowledge of the exact timing of individual key actions. The device records the exact times of each key action, which in this embodiment are the times of each key-down and each key-up, and uses this information. The first application is to catch accidental transpositions during typing. If two characters are entered with a very small time period between them, and the word they are in does not spell correctly using a conventional spell check program resident in the device, the device then spell checks the alternative word with those two characters transposed and, if it is an allowed word, weights this output heavily. This allowed output may be automatically inserted in place of the non-allowed word, or the option of using the allowed word may be presented to the user on a display of the device. Accidental transpositions can also be of command keys; for example one sequence of command keys can result in a non-allowed output or a very infrequently used output, but the transposed command key sequence can be a much more common output. In the present embodiment, the system detects command sequences which follow each other within a predetermined time interval and compares the likelihood of the output associated with the actual command key inputs with the likelihood of the output associated with the transposed command key inputs. Where the likelihood of the transposed key output is sufficiently larger than the output associated with the actual input, the transposed key output is selected in preference. A second use is to catch the case where a Shift key is pressed and released fractionally before a character iskey is pressed down or selected. If the character key is pressed within a very small time period of the Shift key being released, the device automatically corrects the input to the Shifted version of the character key that was pressed. This relies on the system determining that a shift action on its own is meaningless and therefore not allowed through a comparison with a table of allowed actions.

Claims: Claims 1. A method of correcting an input to a device, which a user interacts with by a series of touch actions, comprising the steps of: (a) detecting each touch action; (b) measuring the time interval between one or more touch actions; (c) generating a first output in dependence on the one or more touch actions; (d) checking the first output against a table of allowed outputs; and (e) generating a revised output if the first output is or might be in error and if the time interval satisfies a predetermined time interval criterion. 2. The method of correcting as claimed in Claim 1 in which the device is a physical or touch screen keyboard. 3. The method of correcting as claimed in any preceding Claim in which the touch action is the action of pressing or releasing a key. 4. The method of correcting as claimed in any preceding Claim in which the first output is a word. 5. The method of correcting as claimed in any preceding Claim in which a touch action is touching or releasing the shift key; and the predetermined time interval criterion is that the next touch action occurs after the shift key has been released; and the revised output is that output which would have been generated if the next touch action had in fact occurred whilst the shift key had been selected. 6. The method of correcting as claimed in any preceding Claim in which a touch action is touching a first letter key; and a subsequent touch action is touching a second letter key; the predetermined time interval criterion is that the subsequent touch action occurs within a predetermined time interval of the first touch action; the first output relates to the generation of a word using the letters in the key touch sequence; a dictionary look up process indicates that the generated word is not an allowed word; and the revised output is associated with transposing the order of the first and second letter keys to generate a word which is allowed by the look up dictionary. 7. The method of any preceding Claim in which a first touch action is touching a first command key; and the next touch action is touching a second command key; the predetermined time interval criterion is that the next touch action occurs within a predetermined time interval of the first touch action; the output associated with that sequence of commands is either not allowed or an output of a first likelihood of occurrence; the revised output is that output which would have been generated if the second command key had been selected prior to the first; and the revised output has a higher likelihood of occurrence than the first likelihood. 8. The method of any preceding Claim in which the revised output is a warning message. 9. The method of any preceding Claim in which the predetermined time interval criterion varies as a function of the time interval between one or more touch actions. 10. A computing device operable to perform the method defined in Claims 1 - 9. 11. A computer program operable to perform the method of Claims 1 - 9.

Inventors: HEALEY NICHOLAS, HEALEY, NICHOLAS
Applicants: HEALEY NICHOLAS, PSION COMPUTERS PLC, HEALEY, NICHOLAS
Application year: 2000
Main classification: G06F3
IPC codes: G06F3