Unusual event detection using motion activity descriptors

• US 20030095602A1
• Filed: 11/19/2001
• Published: 05/22/2003
• Est. Priority Date: 11/19/2001
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Research Laboratories, Inc. (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Electric Research Laboratories, Inc. (Mitsubishi Electric Corporation)
• Inventors: Radhakrishnan, Regunathan, Divakaran, Ajay
• Granted Patent: US 6,823,011 B2
• Time in Patent Office: Days
• US Class Current: 375/240.16
• CPC Class Codes: G06V 20/46 Extracting features or characteristics from the video content, e.g. video fingerprints, representative shots or key frames
• CPC Class Codes: G06V 20/52 Surveillance or monitoring of activities, e.g. for recognising suspicious objects recognising microscopic objects G06V20/69
• CPC Class Codes: G06V 40/167 using comparisons between temporally consecutive images
• CPC Class Codes: G06V 40/20 Movements or behaviour, e.g. gesture recognition recognition of facial expressions G06V40/16
• CPC Class Codes: H04N 19/142 Detection of scene cut or scene change
• CPC Class Codes: H04N 19/179 the unit being a scene or a shot
• CPC Class Codes: H04N 19/46 Embedding additional information in the video signal during the compression process H04N19/517, H04N19/68, H04N19/70 take precedence
• CPC Class Codes: H04N 19/503 involving temporal prediction adaptive coding with adaptive selection between spatial and temporal predictive coding H04N19/107; adaptive coding with adaptive selection among a plurality of temporal predictive coding modes H04N19/109
• CPC Class Codes: H04N 19/517 by encoding
• CPC Class Codes: H04N 19/87 involving scene cut or scene change detection in combination with video compression

Abstract

A method detects an unusual event in a video. Motion vectors are extracted from each frame in a video acquired by a camera of a scene. Zero run-length parameters are determined for each frame from the motion vectors. The zero run-length parameters are summed over predetermined time intervals of the video, and a distance is determined between the sum of the zero run-lengths of a current time interval and the sum of the zero run-lengths of a previous time interval. Then, the unusual event is detected if the distance is greater than a predetermined threshold.

Claims

4-1. The method of claim 1 wherein the zero run-length parameters express the number, size, and shape of distinct moving objects in the video.

12. A system for detecting an unusual event in a video, comprising:

a camera acquiring a video of a scene;

means for extracting motion vectors from each frame in the video;

means for determine zero run-length parameters for each frame from the motion vectors;

means for summing the zero run-length parameters over predetermined time intervals of the video;

means for determining a distance between the sum of the zero run-lengths of a current time interval and the sum of the zero run-lengths of a previous time interval; and

an alarm device for signalling the unusual event if the distance is greater than a predetermined threshold.