Method for following at least one object in a scene

• US 7,738,009 B2
• Filed: 03/06/2003
• Issued: 06/15/2010
• Est. Priority Date: 03/13/2002
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Rottmann, Frank
• Primary Examiner(s): DIEP, NHON THANH
• Application Number:
  US10/507,040
• Publication Number:
  US 20050128298A1
• Time in Patent Office: 2,658 Days
• Field of Search: None
• US Class Current: 348/169
• CPC Class Codes: G08B 13/19602 Image analysis to detect motion of the intruder, e.g. by frame subtraction
• 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 13/19613 Recognition of a predetermined image pattern or behaviour pattern indicating theft or intrusion

Abstract

A method is provided for monitoring at least one object in a scene, which method provides that, once a moving object stops and comes to a standstill, the dwell time at standstill is counted so as to generate a signaling as a function of the dwell time. The object is described by a list or a matrix characterizing the direction of movement and the time.

Claims

1. A method for tracking at least one object in a scene, comprising:

detecting, by means of an image detector, a sequence of images of the scene;

determining a movement of at least one object in the scene based on the sequence of images;

starting a counter when the movement of the at least one object comes to a standstill;

enabling counting of the counter only if the at least one object continues to be in the standstill;

generating a signal when a counter value of the counter reaches a predetermined threshold value;

recording the movement of the at least one object as entries in a list, and when the list is full, re-initializing the list while carrying over at least one entry from the list; and

when a most recent entry of the list corresponds to the standstill and the list is full, re-initializing the list while carrying over a most recent entry that corresponds to the movement of the at least one object in addition to carrying over the most recent entry corresponding to the standstill.

2. The method as recited in claim 1, wherein the signal triggers at least one of an audio alarm and visual alarm.

3. The method as recited in claim 1, further comprising:

generating the list to describe the movement of the at least one object with respect to the direction of movement and the time.

4. The method as recited in claim 3, further comprising:

detecting a new movement of the at least one object after coming to the standstill; and

responsive to the detecting of the new movement, re-initializing the list.

5. The method as recited in claim 3, further comprising:

generating a reference image, wherein the reference image is used to identify the at least one object in the scene.

6. The method as recited in claim 5, wherein, after identifying the position of the at least one object, the reference image is adapted onto remaining areas of the scene from at least one preceding image.

7. The method as recited in claim 5, further comprising:

selecting a length of a time interval between the sequence of images, the length being sufficiently long enough to capture a meaningful amount of object movement between images.

8. The method of claim 1, wherein the most recent entry corresponding to the movement of the at least one object and the most recent entry corresponding to the standstill are carried over as respective first and second consecutive entries of the reinitialized list.

9. The method of claim 8, further comprising:

assigning a time to each of the carried over entries, wherein a difference in time between the carried over entries is the same as a difference in time between the entries prior to being carried over.

10. The method as recited in claim 1, further comprising:

generating the list to describe the movement of the at least one object with respect to the direction of movement and the time;

detecting a new movement of the at least one object after coming to the standstill;

responsive to the detecting of the new movement, re-initializing the list;

generating a reference image, wherein the reference image is used to identify the at least one object in the scene; and

selecting a length of a time interval between the sequence of images, the length being sufficiently long enough to capture a meaningful amount of object movement between images,

wherein the signal triggers at least one of an audio alarm and visual alarm, and

wherein, after identifying the position of the at least one object, the reference image is adapted onto remaining areas of the scene from at least one preceding image.

11. A video monitoring system for tracking at least one object in a scene, comprising:

at least one image detector for detecting a sequence of images of the scene;

a processor connected to the image detector for determining a movement of at least one object in the scene based on the sequence of images, wherein the processor starts a time count when the movement of the at least one object comes to a standstill, the time count continuing only if the object continues to be in the standstill;

a memory to store the determined movement of the at least one object as entries in a list; and

an output arrangement connected to the processor for generating a signal when the time count value reaches a predetermined threshold value;

wherein when the list is full, the processor re-initializes the list while carrying over at least one entry from the list, and when a most recent entry of the list corresponds to the standstill and the list is full, the processor re-initializes the list while carrying over a most recent entry that corresponds to the movement of the at least one object in addition to carrying over the most recent entry corresponding to the standstill.

12. The system as recited in claim 11, wherein the processor generates the list to describe the movement of the at least one object with respect to the direction of movement and the time.

13. The system as recited in claim 12, wherein the processor is configured to:

determine a new movement of the at least one object after coming to the standstill; and

responsive to the determining of the new movement, re-initialize the list.

14. The system as recited in claim 12, wherein a reference image is generated, the reference image being used to identify the at least one object in the scene.

15. The system as recited in claim 11, wherein the processor is configured to carry over the most recent entry corresponding to the movement of the at least one object and the most recent entry corresponding to the standstill as respective first and second consecutive entries of the reinitialized list.

16. The system as recited in claim 15, wherein a time is assigned to each of the carried over entries, a difference in time between the carried over entries being the same as a difference in time between the entries prior to being carried over.