Counter-flow detection in compressed video
AssigneeVerint Systems Ltd.
InventorsZvi Figov, Nir Naor
Life of this patent
Estimating the term…
Abstract
A system and method to determine a flow direction automatically so that counter-flow motion may be detected without user calibration is disclosed. The system and method utilize information available from existing video compression algorithms to sense motion and determine a flow direction. Once a flow direction for an area is determined, the system and method can detect counter-flow motion using compressed video without any decompression, thereby improving the speed of detection and simplifying the computational complexity. These improvements facilitate counter-flow alarms and expand the information available to a user monitoring the video.
Claims20
1-20. (canceled)
A method for determining a flow direction for a group of frames in compressed video comprising:
- obtaining motion vectors from a frame in the group of frames, wherein each motion vector comprises a magnitude and an angle,
- filtering the motion vectors to remove motion vectors that correspond to noise,
- computing a frame histogram of the angles of the motion vectors,
- deriving a frame direction based on the frame histogram,
- adding the frame direction to a flow histogram of frame directions,
- repeating the obtaining, filtering, computing, deriving, and adding for other frames in the group of frames, and
- determining a flow direction based on the flow histogram of frame directions.
A video surveillance system having flow motion detection, the system comprising:
- at least one video camera capturing video of a scene;
- a video processing unit (VPU) communicatively coupled to the at least one video camera that processes the video to form a compressed video;
- and
- a video management system (VMS) communicatively coupled to the VPU, wherein the VMS comprises a memory storing software and a processor that is configured by the software to:
- receive the compressed video of the scene, wherein the compressed video comprises frames;
- determine a flow direction for a group of frames in the compressed video, wherein the determining comprises:
- obtaining motion vectors from a frame in the group of the frames, wherein each motion vector comprises a magnitude and an angle;
- filtering the motion vectors to remove motion vectors that correspond to noise,
- computing a frame histogram of the angles of the motion vectors;
- deriving a frame direction based on the frame histogram;
- adding the frame direction to a flow histogram of frame directions,
- repeating the obtaining, filtering, computing, deriving, and adding for other frames in the group of frames;
- and
- determining a flow direction based on the flow histogram of frame directions.
A non-transitory computer readable medium containing computer readable instructions that when executed by a processor of a computing device cause the computing device to perform a method for determining a flow direction for a group of frames in compressed video comprising:
- obtaining motion vectors from a frame in the group of frames, wherein each motion vector comprises a magnitude and an angle;
- filtering the motion vectors to remove motion vectors that correspond to noise;
- computing a frame histogram of the angles of the motion vectors;
- deriving a frame direction based on the frame histogram;
- adding the frame direction to a flow histogram of frame directions;
- repeating the obtaining, filtering, computing, deriving, and adding for other frames in the group of frames;
- and
- determining a flow direction based on the flow histogram of frame directions.
Dependencies are inferred from the claim text.