METHOD, SYSTEM AND APPARATUS FOR TRACKING OBJECTS OF A SCENE

• US 20140321704A1
• Filed: 04/29/2014
• Published: 10/30/2014
• Est. Priority Date: 04/30/2013
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Partis, Ashley John
• Granted Patent: US 9,846,810 B2
• Time in Patent Office: Days
• US Class Current: 382/103
• CPC Class Codes: G06F 18/29 Graphical models, e.g. Bayesian networks
• CPC Class Codes: G06T 2207/20072 Graph-based image processing
• CPC Class Codes: G06T 2207/30196 Human being; Person
• CPC Class Codes: G06T 2207/30241 Trajectory
• CPC Class Codes: G06T 7/20 Analysis of motion motion estimation for coding, decoding, compressing or decompressing digital video signals H04N19/43, H04N19/51
• CPC Class Codes: G06V 10/62 relating to a temporal dimension, e.g. time-based feature extraction; Pattern tracking
• CPC Class Codes: G06V 10/84 using probabilistic graphical models from image or video features, e.g. Markov models or Bayesian networks
• 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 20/53 Recognition of crowd images, e.g. recognition of crowd congestion

Abstract

A method of tracking objects of a scene is disclosed. The method determines two or more tracks which have merged. Each track is associated with at least one of the objects and having a corresponding graph structure. Each graph structure comprising at least one node representing the corresponding track. A new node representing the merged tracks is created. The graph structures are added as children nodes of the new node to create a merged graph structure. A split between the objects associated with one of the tracks represented by the nodes of the merged graph structure is determined. Similarity between one or more of the nodes in the merged graph structure and foreground areas corresponding to split objects is determined. One of the nodes in the merged graph structure is selected based on the determined similarity. A new graph structure for tracking the objects is created, the new graph structure having the selected node at the root of the new graph structure.

Claims

1. A method of tracking objects of a scene, said method comprising:

determining two or more tracks which have merged, each track being associated with at least one of the objects and having a corresponding graph structure, each graph structure comprising at least one node representing the corresponding track;

creating a new node representing the merged tracks;

adding said graph structures as children nodes of the new node to create a merged graph structure;

detecting a split between the objects associated with one of the tracks represented by said nodes of the merged graph structure;

determining similarity between one or more of said nodes in the merged graph structure and foreground areas corresponding to split objects;

selecting one of said nodes in the merged graph structure based on the determined similarity; and

creating a new graph structure for tracking the objects in response to the detection of the split, the new graph structure having the selected node at the root of the new graph structure.

2. The method according to claim 1, wherein hierarchy of the nodes under the selected node is maintained in the new graph structure.

3. The method according to claim 1, further comprising merging graph structures corresponding to the tracks associated with the split.

4. The method according to claim 1, further comprising creating further new graph structures for tracks that do not correspond to one of said nodes.

5. A system for tracking objects of a scene, said system comprising:

a memory for storing data and a computer program;

a processor coupled to said memory for executing said computer program, said computer program comprising instructions for;

determining two or more tracks which have merged, each track being associated with at least one of the objects and having a corresponding graph structure, each graph structure comprising at least one node representing the corresponding track;

creating a new node representing the merged tracks;

adding said graph structures as children nodes of the new node to create a merged graph structure;

detecting a split between the objects associated with one of the tracks represented by said nodes of the merged graph structure;

determining similarity between one or more of said nodes in the merged graph structure and foreground areas corresponding to split objects;

selecting one of said nodes in the merged graph structure based on the determined similarity; and

creating a new graph structure for tracking the objects in response to the detection of the split, the new graph structure having the selected node at the root of the new graph structure.

6. An apparatus for tracking objects of a scene, said apparatus comprising:

means for determining two or more tracks which have merged, each track being associated with at least one of the objects and having a corresponding graph structure, each graph structure comprising at least one node representing the corresponding track;

means for creating a new node representing the merged tracks;

means for adding said graph structures as children nodes of the new node to create a merged graph structure;

means for detecting a split between the objects associated with one of the tracks represented by said nodes of the merged graph structure;

means for determining similarity between one or more of said nodes in the merged graph structure and foreground areas corresponding to split objects;

means for selecting one of said nodes in the merged graph structure based on the determined similarity; and

means for creating a new graph structure for tracking the objects in response to the detection of the split, the new graph structure having the selected node at the root of the new graph structure.

7. A computer readable medium having a computer program stored thereon for tracking objects of a scene, said program comprising:

code for determining two or more tracks which have merged, each track being associated with at least one of the objects and having a corresponding graph structure, each graph structure comprising at least one node representing the corresponding track;

code for creating a new node representing the merged tracks;

code for adding said graph structures as children nodes of the new node to create a merged graph structure;

code for detecting a split between the objects associated with one of the tracks represented by said nodes of the merged graph structure;

code for determining similarity between one or more of said nodes in the merged graph structure and foreground areas corresponding to split objects;

code for selecting one of said nodes in the merged graph structure based on the determined similarity; and

code for creating a new graph structure for tracking the objects in response to the detection of the split, the new graph structure having the selected node at the root of the new graph structure.