Authenticating a user using hand gesture
First Claim
1. A computer implemented method for authenticating a user into a system using a gesture drawn by the user, the method comprising:
- dividing a trajectory defined by said gesture into a plurality of portions;
defining, for each portion, a virtual segment based on an average direction of the portion;
measuring a difference (d) between the virtual segment and the trajectory associated therewith at a number n of different locations within the trajectory, thus obtaining a set of di=1−
n;
classifying each set of di=1−
n as a sample point in a multidimensional space of at least n dimensions, said multidimensional space including sample points for the user (Yes samples) and sample points for other people (No samples);
determining for each set of di=1−
n a probability that the portion associated with that set is drawn by the user, said determining comprising;
counting a number of Yes samples and a number of No samples within a predefined volume around the sample point associated with the set of d1−
n;
calculating a first ratio of Yes samples versus No samples within the predefined volume;
dividing the first ratio by a second ratio representing the number of Yes samples versus No samples in the entire multidimensional space, to produce said probability;
aggregating the probabilities associated with each portion to produce an aggregated probability for the gesture;
outputting said aggregated probability to the system for comparison with a predetermined threshold to take an authentication decision or action based on said comparison.
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Abstract
The present document describes a method for authenticating a user into a system using gestures. The user may draw the gesture on a touch sensitive device (e.g. touchpad), or make the gesture in the air in front of a camera. In the touchpad embodiment, the trajectory defined by the gesture is received ready from the touchpad. In the camera embodiment, the trajectory is built by analyzing the images of an image stream to find a hand (or another subject i.e. meta-subject). The trajectory may then be built by monitoring the change of position of the hand in the succession of images. The trajectory is analyzed to determine the key-code defined by the gesture, and to determine whether or not it is the authenticated user who is performing the gesture (as opposed to an intruder) based on the speed and the distance between the trajectory and a straight line.
36 Citations
67 Claims
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1. A computer implemented method for authenticating a user into a system using a gesture drawn by the user, the method comprising:
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dividing a trajectory defined by said gesture into a plurality of portions; defining, for each portion, a virtual segment based on an average direction of the portion; measuring a difference (d) between the virtual segment and the trajectory associated therewith at a number n of different locations within the trajectory, thus obtaining a set of di=1−
n;classifying each set of di=1−
n as a sample point in a multidimensional space of at least n dimensions, said multidimensional space including sample points for the user (Yes samples) and sample points for other people (No samples);determining for each set of di=1−
n a probability that the portion associated with that set is drawn by the user, said determining comprising;counting a number of Yes samples and a number of No samples within a predefined volume around the sample point associated with the set of d1−
n;calculating a first ratio of Yes samples versus No samples within the predefined volume; dividing the first ratio by a second ratio representing the number of Yes samples versus No samples in the entire multidimensional space, to produce said probability; aggregating the probabilities associated with each portion to produce an aggregated probability for the gesture; outputting said aggregated probability to the system for comparison with a predetermined threshold to take an authentication decision or action based on said comparison. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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33. A computer implemented method for authenticating a user into a system using a gesture drawn by the user, the method comprising:
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dividing a trajectory defined by said gesture into a plurality of portions; defining, for each portion, a virtual segment based on an average direction of the portion; measuring a difference (d) between the virtual segment and the trajectory associated therewith at a number n of different locations within the trajectory, thus obtaining a set of di=1−
n;classifying each set of di=1−
n as a sample point in a multidimensional space of at least n dimensions, said multidimensional space including sample points for the user (Yes samples) and sample points for other people (No samples);determining for at least one set of di=1−
n a probability that the portion associated with that set is drawn by the user, said determining comprising;counting a number of Yes samples and a number of No samples within a predefined volume around the sample point associated with the set of d1−
n;calculating a first ratio of Yes samples versus No samples within the predefined volume; dividing the first ratio by a second ratio representing the number of Yes samples versus No samples in the entire multidimensional space, to produce said probability; outputting the probability associated with each portion to the system for comparison with a predetermined threshold to take an authentication decision or action based on said comparison.
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34. An apparatus for authenticating a user into a system using a gesture drawn by the user, the system comprising:
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a trajectory analyzer adapted to; divide a trajectory defined by said gesture into a plurality of portions, define, for each portion, a virtual segment based on an average direction of the portion; measure a difference (d) between the virtual segment and the trajectory associated therewith at a number n of different locations within the trajectory, to obtaining a set of di=1−
n;an authentication module adapted to; classify each set of di=1−
n as a sample point in a multidimensional space of at least n dimensions, said multidimensional space including sample points for the user (Yes samples) and sample points for other people (No samples); anddetermine for each set of di=1−
n a probability that the portion associated with that set is drawn by the user, by counting a number of Yes samples and a number of No samples within a predefined volume around the sample point associated with the set of di=1−
n;
calculating a first ratio of Yes samples versus No samples within the predefined volume; and
dividing the first ratio by a second ratio representing the number of Yes samples versus No samples in the entire multidimensional space, to produce said probability;a probability aggregator for aggregating the probabilities associated with each portion to produce an aggregated probability for the gesture, wherein the aggregated probability is sent to the system for comparison with a predetermined threshold to take an authentication decision or a decision based on said comparison. - View Dependent Claims (35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67)
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Specification