Video surveillance system employing video primitives
First Claim
Patent Images
1. A method of video surveillance, comprising:
- receiving, by a computer system, a video comprising video images from a video sensor,the computer system performing the steps of;
analyzing the video to detect stationary objects in the video using background subtraction of a background model;
analyzing the video to detect people in the video by using frame differencing to detect foreground objects;
upon detecting a first stationary object in the video, defining a zone as a portion of the video around the first stationary object, defining the zone being responsive to a location of the first stationary object, the zone being defined to be larger than an outer boundary of the first stationary object and smaller than a field of view of the video, a size of the zone allowing detection of multiple non-overlapping objects;
tracking a duration that the first stationary object remains stationary;
determining an occurrence of an external event;
issuing an alert in response to determining that the duration of time the first stationary object has remained stationary exceeds a threshold while no person of interest detected in the video has been inside the zone and the occurrence of the external event; and
determining a crowd density in the video,wherein the size of the zone is determined dynamically and is responsive to the determined crowd density.
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Abstract
A video surveillance system is set up, calibrated, tasked, and operated. The system extracts video primitives and extracts event occurrences from the video primitives using event discriminators. The system can undertake a response, such as an alarm, based on extracted event occurrences.
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Citations
23 Claims
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1. A method of video surveillance, comprising:
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receiving, by a computer system, a video comprising video images from a video sensor, the computer system performing the steps of; analyzing the video to detect stationary objects in the video using background subtraction of a background model; analyzing the video to detect people in the video by using frame differencing to detect foreground objects; upon detecting a first stationary object in the video, defining a zone as a portion of the video around the first stationary object, defining the zone being responsive to a location of the first stationary object, the zone being defined to be larger than an outer boundary of the first stationary object and smaller than a field of view of the video, a size of the zone allowing detection of multiple non-overlapping objects; tracking a duration that the first stationary object remains stationary; determining an occurrence of an external event; issuing an alert in response to determining that the duration of time the first stationary object has remained stationary exceeds a threshold while no person of interest detected in the video has been inside the zone and the occurrence of the external event; and determining a crowd density in the video, wherein the size of the zone is determined dynamically and is responsive to the determined crowd density. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method of video surveillance, comprising:
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receiving, by a computer system, a video comprising video images from a video sensor, the computer system performing the steps of; analyzing the video to detect stationary objects in the video using background subtraction of a background model; analyzing the video to detect people in the video by using frame differencing to detect foreground objects; upon detecting a first stationary object in the video, defining a zone as a portion of the video around the first stationary object, defining the zone being responsive to a location of the first stationary object, the zone being defined to be larger than an outer boundary of the first stationary object and smaller than a field of view of the video, a size of the zone allowing detection of multiple non-overlapping objects; tracking a duration that the first stationary object remains stationary; determining an occurrence of an external event; issuing an alert in response to the determining of the occurrence of the external event and determining that the duration of time the first stationary object has remained stationary exceeds a threshold while at least one of the following occurs; no person of interest detected in the video has been detected as being in the zone, and no person of interest detected in the video has been detected as being in the zone longer than a first period of time; and determining a crowd density in the video, wherein the size of the zone is determined dynamically and is responsive to the determined crowd density. - View Dependent Claims (15)
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16. A method of video surveillance, comprising:
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receiving, by a computer system, a video comprising video images from a video sensor, the computer system performing the steps of; analyzing the video to detect stationary objects in the video using background subtraction of a background model; analyzing the video to detect people in the video by using frame differencing to detect foreground objects; upon detecting a first stationary object in the video, defining a zone as a portion of the video around the first stationary object, defining the zone being responsive to a location of the first stationary object, the zone being defined to be larger than an outer boundary of the first stationary object and smaller than a field of view of the video, a size of the zone allowing detection of multiple non-overlapping objects; tracking a duration that the first stationary object remains stationary; determining an occurrence of an external event; issuing an alert in response to determining that the duration of time the first stationary object has remained stationary exceeds a threshold while no person of interest detected in the video has been inside the zone and the occurrence of the external event; and determining a security threat level, wherein the size of the zone is responsive to the determined security threat level. - View Dependent Claims (17)
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18. A method of video surveillance, comprising:
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receiving, by a computer system, a video comprising video images from a video sensor, the computer system performing the steps of; analyzing the video to detect stationary objects in the video using background subtraction of a background model; analyzing the video to detect people in the video by using frame differencing to detect foreground objects; upon detecting a first stationary object in the video, defining a zone as a portion of the video around the first stationary object, defining the zone being responsive to a location of the first stationary object, the zone being defined to be larger than an outer boundary of the first stationary object and smaller than a field of view of the video, a size of the zone allowing detection of multiple non-overlapping objects; tracking a duration that the first stationary object remains stationary; determining an occurrence of an external event; and issuing an alert in response to determining that the duration of time the first stationary object has remained stationary exceeds a threshold while no person of interest detected in the video has been inside the zone and the occurrence of the external event, wherein the size of the zone is responsive to detection of other stationary objects prior to the detecting of the first stationary object. - View Dependent Claims (19, 20, 21)
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22. A method of video surveillance, comprising:
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receiving, by a computer system, a video comprising video images from a video sensor, the computer system performing the steps of; analyzing the video to detect stationary objects in the video using background subtraction of a background model; analyzing the video to detect people in the video by using frame differencing to detect foreground objects; upon detecting a first stationary object in the video, defining a zone as a portion of the video around the first stationary object, defining the zone being responsive to a location of the first stationary object, the zone being defined to be larger than an outer boundary of the first stationary object and smaller than a field of view of the video, a size of the zone allowing detection of multiple non-overlapping objects; tracking a duration that the first stationary object remains stationary; determining an occurrence of an external event; issuing an alert in response to the determining of the occurrence of the external event and determining that the duration of time the first stationary object has remained stationary exceeds a threshold while, during a first period of time, a person of interest detected in the video has been detected as being in the zone only for part of the first period of time; and determining a crowd density in the video, wherein the size of the zone is determined dynamically and is responsive to the determined crowd density. - View Dependent Claims (23)
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Specification