Video surveillance system in which trajectory hypothesis spawning allows for trajectory splitting and/or merging

• US 20050104961A1
• Filed: 08/12/2004
• Published: 05/19/2005
• Est. Priority Date: 11/17/2003
• Status: Active Grant

• Current Assignee: Axis AB (Canon Inc.)
• Original Assignee: Vidient Systems, Inc. (Agilence Incorporated)
• Inventors: Gong, Yihong, Han, Mei, Tao, Hai
• Granted Patent: US 7,148,912 B2
• Time in Patent Office: Days
• US Class Current: 348/143
• CPC Class Codes: G08B 13/19604 involving reference image or background adaptation with time to compensate for changing conditions, e.g. reference image update on detection of light level change
• CPC Class Codes: G08B 13/19608 Tracking movement of a target, e.g. by detecting an object predefined as a target, using target direction and or velocity to predict its new position
• CPC Class Codes: G08B 13/19615 wherein said pattern is defined by the user
• CPC Class Codes: G08B 13/19652 Systems using zones in a single scene defined for different treatment, e.g. outer zone gives pre-alarm, inner zone gives alarm
• CPC Class Codes: G08B 31/00 Predictive alarm systems characterised by extrapolation or other computation using updated historic data

Abstract

A video surveillance system uses rule-based reasoning and multiple-hypothesis scoring to detect predefined behaviors based on movement through zone patterns. Trajectory hypothesis spawning allows for trajectory splitting and/or merging and includes local pruning to managed hypothesis growth. Hypotheses are scored based on a number of criteria, illustratively including at least one non-spatial parameter. Connection probabilities computed during the hypothesis spawning process are based on a number of criteria, illustratively including object size. Object detection and probability scoring is illustratively based on object class.

Claims

1. A method for use in a video surveillance system, the method comprising

generating a first plurality of hypotheses, each said hypothesis comprising a respective set of hypothesized trajectories of objects hypothesized to have been moving through an area under surveillance at a previous time,

hypothesizing the presence of particular objects in the surveillance space at a present time, and

generating a second plurality of extended hypotheses each associated with a respective one of said first plurality of hypotheses, at least one of the extended hypotheses including at least one of a) at least two of the trajectories of the associated first hypothesis extended to the same one of said particular objects or b) at least one of said trajectories of the associated first hypothesis extended to at least two of said particular objects.

2. The method of claim 1 wherein at least of said extended hypotheses includes each of the trajectories of the associated first hypothesis, at least ones of those trajectories being extended to at least one of said particular objects.

3. An electronic surveillance system adapted to carry out the method of claim 1.

4. A tangible medium on which are stored instructions that are executable by a processor to carry out the method of claim 1.