Loitering detection in a video surveillance system
AssigneeBehavioral Recognition Systems, Inc.
InventorsGang Xu, Wesley Kenneth Cobb
Life of this patent
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Abstract
A behavioral recognition system may include both a computer vision engine and a machine learning engine configured to observe and learn patterns of behavior in video data. Certain embodiments may be configured to learn patterns of behavior consistent with a person loitering and generate alerts for same. Upon receiving information of a foreground object remaining in a scene over a threshold period of time, a loitering detection module evaluates the whether the object trajectory corresponds to a random walk. Upon determining that the trajectory does correspond, the loitering detection module generates a loitering alert.
Claims24
A method for detecting loitering behavior of objects depicted in a scene captured by a video camera, the method comprising:
- receiving a trajectory for an object in the scene, wherein the object has been in the scene for a time period, and wherein the trajectory tracks a two-dimensional (2D) path of the object relative to a series of video frames in which the object is depicted;
- and
- upon determining that the time period that the object has been in the scene is greater than a threshold time period and determining that the trajectory corresponds to a random walk, generating a loitering alert, wherein determining whether the trajectory corresponds to a random walk comprises:
- calculating a global loitering score, wherein the global loitering score is based on a distance between a final point in the trajectory and a starting point in the trajectory,
- calculating at least one local loitering score, wherein each local loitering score is based on a distance between the final point and a respective intermediate point in the trajectory,
- calculating an estimated loitering score as an average of the global loitering score and the at least one local loitering score, and
- comparing the estimated loitering score with a threshold loitering score, wherein the trajectory corresponds to a random walk if the estimated loitering score is greater than the threshold loitering score.
A non-transitory computer-readable storage medium storing instructions, which, when executed on a processor, performs an operation for detecting loitering behavior, the operation comprising:
- receiving a trajectory for an object in the scene, wherein the object has been in the scene for a time period, and wherein the trajectory tracks a two-dimensional (2D) path of the object relative to a series of video frames in which the object is depicted;
- and
- upon determining that the time period that the object has been in the scene is greater than a threshold time period and determining that the trajectory corresponds to a random walk, generating a loitering alert, wherein determining whether the trajectory corresponds to a random walk comprises:
- calculating a global loitering score, wherein the global loitering score is based on a distance between a final point in the trajectory and a starting point in the trajectory,
- calculating at least one local loitering score, wherein each local loitering score is based on a distance between the final point and a respective intermediate point in the trajectory,
- calculating an estimated loitering score as an average of the global loitering score and the at least one local loitering score, and
- comparing the estimated loitering score with a threshold loitering score, wherein the trajectory corresponds to a random walk if the estimated loitering score is greater than the threshold loitering score.
A system comprising:
- a processor;
- and
- a memory hosting an application, which, when executed on the processor, performs an operation for detecting loitering behavior, the operation comprising:
- receiving a trajectory for an object in the scene, wherein the object has been in the scene for a time period, and wherein the trajectory tracks a two-dimensional (2D) path of the object relative to a series of video frames in which the object is depicted, and
- upon determining that the time period that the object has been in the scene is greater than a threshold time period and determining that the trajectory corresponds to a random walk, generating a loitering alert, wherein determining whether the trajectory corresponds to a random walk comprises:
- calculating a global loitering score, wherein the global loitering score is based on a distance between a final point in the trajectory and a starting point in the trajectory;
- calculating at least one local loitering score, wherein each local loitering score is based on a distance between the final point and a respective intermediate point in the trajectory;
- calculating an estimated loitering score as an average of the global loitering score and the at least one local loitering score;
- and
- comparing the estimated loitering score with a threshold loitering score, wherein the trajectory corresponds to a random walk if the estimated loitering score is greater than the threshold loitering score.
Dependencies are inferred from the claim text.