System and method for recognizing touch typing under limited tactile feedback conditions
First Claim
1. A typing recognition apparatus for touch typing on surfaces with limited tactile feedback that compensates for finger and hand drift during typing and discourages any integrated spelling model from choosing dictionary words over unusual but carefully typed strings, the apparatus comprising:
- a typing surface means that displays symbols indicating the locations of touchable keys;
touch sensor means that provides the surface coordinates of each touch by a typist attempting to strike said key symbols on said surface;
hypothesis tree generator means that extends existing key hypothesis sequences with hypotheses for keys in the neighborhood of each new touch;
pattern geometry evaluation means that computes geometry match metrics for the hypothesized key sequences by comparing separation vectors between the successive touch locations with separation vectors between the successively hypothesized key locations as well as by measuring the zero-order key/touch alignment error;
decoding means that finds the hypothesized key sequence with the best cumulative match metric; and
, transmission means for communicating the symbols and commands represented by the best hypothesized key sequence to host computer applications.
1 Assignment
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Accused Products
Abstract
A system is disclosed for recognizing typing from typing transducers that provide the typist with only limited tactile feedback of key position. The system includes a typing decoder sensitive to the geometric pattern of a keystroke sequence as well as the distance between individual finger touches and nearby keys. The typing decoder hypothesizes plausible key sequences and compares their geometric pattern to the geometric pattern of corresponding finger touches. It may also hypothesize home row key locations for touches caused by hands resting on or near home row. The resulting pattern match metrics may be combined with character sequence transition probabilities from a spelling model. The typing decoder then chooses the hypothesis sequence with the best cumulative match metric and sends it as key codes or commands to a host computing device.
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Citations
38 Claims
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1. A typing recognition apparatus for touch typing on surfaces with limited tactile feedback that compensates for finger and hand drift during typing and discourages any integrated spelling model from choosing dictionary words over unusual but carefully typed strings, the apparatus comprising:
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a typing surface means that displays symbols indicating the locations of touchable keys;
touch sensor means that provides the surface coordinates of each touch by a typist attempting to strike said key symbols on said surface;
hypothesis tree generator means that extends existing key hypothesis sequences with hypotheses for keys in the neighborhood of each new touch;
pattern geometry evaluation means that computes geometry match metrics for the hypothesized key sequences by comparing separation vectors between the successive touch locations with separation vectors between the successively hypothesized key locations as well as by measuring the zero-order key/touch alignment error;
decoding means that finds the hypothesized key sequence with the best cumulative match metric; and
,transmission means for communicating the symbols and commands represented by the best hypothesized key sequence to host computer applications. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for recognizing typing from typing devices that sense lateral finger position but provide limited tactile feedback of key location, the method advantageously compensating for finger and hand drift during typing and discouraging any integrated spelling model from choosing dictionary words over unusual but carefully typed strings, wherein the method comprises the following steps:
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forming a touch location and time sequence from the fingertip position at the end of each keystroke as measured by typing sensors;
computing a set of touch separation vectors of increasing orders from the location difference between the newest touch and previous touch in said touch location sequence;
generating a set of key hypothesis sequences for the given touch sequence, each hypothesis in a sequence being for a key near the location of the touch causing the hypothesis;
for each key hypothesis, computing a set of key separation vectors of increasing orders from differences between the position of the newest key and previous keys in the hypothesized sequence;
for each key hypothesis, computing a geometry match metric as a function of the magnitude of the zero-order touch/key alignment error as well as of the magnitudes of each order'"'"'s touch and key separation vector difference;
combining the geometry match metrics from each hypothesis in a key hypothesis sequence into a cumulative match metric for the hypothesis sequence;
choosing the hypothesized key sequence with the best cumulative metric as the best hypothesized key sequence; and
,transmitting the symbols and commands represented by the best hypothesized key sequence to a host computer for further action. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A method for recognizing typing from typing devices that sense lateral finger position but provide limited tactile feedback of key location, the method advantageously compensating for finger and hand drift during typing and discouraging any integrated spelling model from choosing dictionary words over unusual but carefully typed strings, wherein the method comprises the following steps:
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forming a touch location and time sequence from the fingertip position at the end of each keystroke as measured by typing sensors;
generating a set of key hypothesis sequences for the given touch sequence, each hypothesis in a sequence being for a key near the location of the touch causing the hypothesis;
for each key hypothesis, computing a key/touch alignment error vector as the difference between the location of the hypothesized key and the location of its causing touch;
for each key hypothesis, computing a geometry match metric as a function of the magnitude of the hypothesis'"'"' key/touch alignment error as well as of the magnitude of differences between the hypothesis'"'"' key/touch alignment error vector and that of preceding hypotheses in its sequence;
combining the geometry match metrics from each hypothesis in a key hypothesis sequence into a cumulative match metric for the hypothesis sequence;
choosing the hypothesized key sequence with the best cumulative metric as the best hypothesized key sequence; and
,transmitting the symbols and commands represented by the best hypothesized key sequence to a host computer for further action. - View Dependent Claims (14, 15, 16, 17, 18)
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19. A typing recognition apparatus comprising:
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a typing surface;
at least one touch sensor configured to provide surface coordinates of each touch by a typist to the typing surface;
a hypothesis tree generator configured to generate key hypothesis sequences from the surface coordinates of each touch; and
a pattern geometry evaluator configured to compute a geometry match metric for each of the key hypothesis sequences. - View Dependent Claims (20, 21)
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22. A method for recognizing typing, the method comprising:
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receiving a touch location and time sequence for a plurality of keystrokes;
generating a set of key hypothesis sequences for the plurality of keystrokes;
computing a geometry match metric for each key hypothesis sequence; and
choosing a best hypothesized key sequence based on the geometry match metrics.
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23. A typing recognition apparatus that compensates for finger and hand drift during typing on a touch-sensitive surface, the apparatus comprising:
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sensor scanning hardware configured for providing surface coordinates of each touch received on the touch-sensitive surface; and
a processor programmed for extending existing key hypothesis sequences with hypotheses for keys in a neighborhood of each new touch, computing geometry match metrics for the hypothesized key sequences by comparing touch separation vectors between successive touch locations with key separation vectors between successively hypothesized key locations and measuring zero-order key/touch alignment error, computing a character transition cost for each of the hypothesized key sequences based on whether the hypothesized key sequence is building a dictionary word, selecting a best hypothesized key sequence from the hypothesized key sequences, the best hypothesized key sequence having a best cumulative match metric formulated from the geometry match metric and the character transition cost, and communicating symbols and commands represented by the best hypothesized key sequence to a host computer application. - View Dependent Claims (24, 25, 26)
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27. A method for compensating for finger and hand drift during typing on a touch-sensitive surface, comprising:
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obtaining a touch location and time sequence for each detected touch in a touch sequence;
computing a set of touch separation vectors of increasing orders between the detected touches in the touch sequence;
generating a set of key hypothesis sequences for each touch in the touch sequence, each key hypothesis sequence associated with a key near the location of the touch;
for each key hypothesis sequence, computing a set of key separation vectors of increasing orders between the keys in the hypothesized key sequence;
for each key hypothesis sequence, computing a geometry match metric as a function of a magnitude of a zero-order touch/key alignment error and the magnitudes of each order'"'"'s touch and key separation vector difference;
computing a character transition cost for each of the hypothesized key sequences based on whether the hypothesized key sequence is building a dictionary word;
selecting a best hypothesized key sequence from the hypothesized key sequences, the best hypothesized key sequence having a best cumulative match metric formulated from the geometry match metric and the character transition cost, and transmitting symbols and commands represented by the best hypothesized key sequence to a host computer for further action. - View Dependent Claims (28, 29, 30)
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31. A typing recognition apparatus comprising:
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a typing surface;
at least one touch sensor integrated with the typing surface and configured to provide surface coordinates of each touch on the typing surface;
a hypothesis tree generator configured to generate key hypothesis sequences from the surface coordinates of each touch;
a pattern geometry evaluator configured to compute a geometry match metric for each of the key hypothesis sequences;
a dictionary selector configured to compute a character transition cost for each of the key hypothesis sequences based on whether the hypothesized key sequence is building a dictionary word; and
a decoder configured for selecting a best hypothesized key sequence from the hypothesized key sequences, the best hypothesized key sequence having a best cumulative match metric formulated from the geometry match metric and the character transition cost. - View Dependent Claims (32, 33, 34)
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35. A method for recognizing typing, the method comprising:
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receiving a touch location and time sequence for a plurality of keystrokes;
generating a set of key hypothesis sequences for the plurality of keystrokes;
computing a geometry match metric for each key hypothesis sequence;
computing a character transition cost for each key hypothesis sequence based on whether the key hypothesis sequence is building a dictionary word; and
selecting a best hypothesized key sequence from the hypothesized key sequences, the best hypothesized key sequence having a best cumulative match metric formulated from the geometry match metric and the character transition cost. - View Dependent Claims (36, 37, 38)
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Specification