Data entry using sequential keystrokes
First Claim
1. A method for designing a keyboard for inputting characters from a set of characters, the keyboard having a plurality of keys, the method comprising:
- assigning a first weight to a first character from the set of characters;
assigning a second weight to a second character from the set of characters; and
generating, using a prefix-free encoding, a first keystroke sequence for said first character and a second keystroke sequence for said second character based on said first weight and said second weight.
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Abstract
A method for designing a keyboard for efficient data entry. A user inputs data from a predefined set of characters such as letters or symbols on an input device by pressing one or more keys, in a sequential fashion, for each character. Based on the frequency of occurrence for each character, a prefix-free coding is used to generate an optimal or near-optimal key sequence mapping for the given character set. In one exemplary embodiment, eight to twelve keys from a phone keypad are used to generate English alphabets, which substantially reduces the average number of keystrokes per character. The present invention enables the user to efficiently input typical data from a given probability distribution of characters using a limited number of keys.
85 Citations
20 Claims
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1. A method for designing a keyboard for inputting characters from a set of characters, the keyboard having a plurality of keys, the method comprising:
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assigning a first weight to a first character from the set of characters; assigning a second weight to a second character from the set of characters; and generating, using a prefix-free encoding, a first keystroke sequence for said first character and a second keystroke sequence for said second character based on said first weight and said second weight. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A machine readable medium, the machine readable medium containing machine executable program instructions which, when executed by a data processing system, causes the data processing system to perform a method for generating characters from a set of characters, the data processing system being coupled to a keyboard, the keyboard being configured to generate keystroke sequences from a plurality of keys, the method comprising:
generating a first signal for a first character when a first keystroke sequence is inputted, said first keystroke sequence being included in a table comprising a plurality of entries, wherein each entry of said table comprises a mapping associating a keystroke sequence with a character from the set of characters, wherein said first character corresponds to said first keystroke sequence according to said table, wherein there exists an entry in said table comprising another keystroke sequence which has a different length from said first keystroke sequence, and wherein said table is generated such that dividing said keystroke sequence into a first subsequence and a second subsequence does not result in said first subsequence being a valid keystroke sequence in said table if said first subsequence comprises at least one keystroke and said second subsequence comprises at least one keystroke. - View Dependent Claims (11, 12, 13, 14)
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15. A data input system for generating character signals from a set of characters, the system comprising:
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a keyboard comprising a plurality of keys; a key signal detector coupled to said keyboard, said key signal detector being configured for detecting a keystroke of a key from said plurality of keys; and a character signal generator coupled to said key signal detector, said character signal generator being configured for generating a character signal when a keystroke sequence from a plurality of predefined key sequences is detected, wherein said plurality of predefined key sequences is generated using a variable-length prefix-fee encoding. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification