Object tracking method and apparatus using template matching

• US 7,113,616 B2
• Filed: 12/04/2002
• Issued: 09/26/2006
• Est. Priority Date: 12/05/2001
• Status: Active Grant

• Current Assignee: Hitachi Kokusai Electric Incorporated (Hitachi, Ltd.)
• Original Assignee: Hitachi Kokusai Electric Incorporated (Hitachi, Ltd.)
• Inventors: Ito, Wataru, Ogura, Shinya, Ueda, Hirotada
• Primary Examiner(s): Ahmed, Samir
• Assistant Examiner(s): Mistry, ONeal R.
• Application Number:
  US10/309,231
• Publication Number:
  US 20030103648A1
• Time in Patent Office: 1,392 Days
• Field of Search: None
• US Class Current: 382/103
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 2207/30196 Human being; Person
• CPC Class Codes: G06T 7/248 involving reference images or patches
• CPC Class Codes: G06T 7/254 involving subtraction of images
• 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 13/19689 Remote control of cameras, e.g. remote orientation or image zooming control for a PTZ camera
• CPC Class Codes: G08B 13/19691 Signalling events for better perception by user, e.g. indicating alarms by making display brighter, adding text, creating a sound

Abstract

An object is detected in comparison between an input image from an image pick-up device having a zoom mechanism and a template image stored in a manner that a first image within a view field of the image pick-up device is stored as a first as the template image, a power of the zoom mechanism to be changed is recorded, a second image to be detected is picked-up from the image pick-up device. Then, a size of either one of the template image and the second image is changed on the bases of the changed power of the zoom mechanism, and a template matching is performed between the template image and the second image to detect the object. This process makes it possible to track an object within the view field.

Claims

1. An object detecting method for detecting an object in comparison between an input image from an image pick-up device having a zoom mechanism and a template image stored in memory, said object detecting method comprising the step of:

storing a first image within a view field of said image pick-up device as said template image;

recording a power of said zoom mechanism to be changed;

pick-up a second image to be detected from said image pick-up device;

changing a size of either one of said template image and said second image on the bases of said changed power of said zoom mechanism; and

performing a template between said template image and said second image to detect said object,

wherein the step of recording a power of said zoom mechanism to be changed comprises the steps of;

storing a first focal distance of said zoom mechanism at a time when said template image is picked-up, and

detecting a second focal distance of said zoom mechanism at a time when a second image from said image pick-up device is picked-up.

2. An object detecting method according to claim 1, wherein said step of storing said first image as said template image includes the steps of:

setting an area having a predetermined size containing said object and controlling said zoom mechanism so that said object is included in said area.

3. An object detecting method according to claim 1, wherein said step of performing a template matching is a step of detecting a position of a partial image with a maximum degree of coincidence with said template image from said second image.

4. An object detecting method according to claim 1, wherein said zoom mechanism is either one of a zoom lens and an electronic zoom.

5. An object detecting method according to claim 4, wherein said zoom mechanism is said zoom lens, and said object detecting method further comprises the steps of:

changing manually said focal distances of said zoom lens and displaying said input image on a screen of a display,

wherein an operator operates said zoom lens as viewing said input image on said screen.

6. An object detecting method according to claim 4, wherein said zoom mechanism is said zoom lens, the focal distance of said zoom lens is calculated after a passage of time from a predetermined reference time after a zoom control is started.

7. An object detecting method according to claim 1, said object detecting method further comprises the step of:

updating said template image stored to a new template image on the bases of the results to perform a template matching.

8. An object detecting apparatus for detecting an object in comparison between an input image from an image pick-up device having a zoom mechanism and a template image stored in memory, said object detecting apparatus comprising:

a storing unit for storing a first image within a view field of said image pick-up device as said template image;

a recording unit for recording a power of said zoom mechanism to be changed;

a picking-up unit for detecting a second image from said image pick-up device;

a control unit for changing a size of either one of said template image and said second image on the bases of said changed power of said zoom mechanism; and

a processing unit for performing a template matching,

wherein said recording unit for recording a power of said zoom mechanism to be changed stores a first focal distance of said zoom mechanism at a time when said template image is picked-up and detects a second focal distance of said zoom mechanism at a time when a second image from said image pick-up device is picked-up.

9. An object detecting apparatus according to claim 8, wherein said control unit controls said zoom mechanism so that said first image as said template image includes an area having a predetermined size containing said object and said object is included in said area.

10. An object detecting apparatus according to claim 8, wherein said zoom mechanism is either one of a zoom lens and an electronic zoom.

11. An object detecting apparatus according to claim 10, wherein said zoom mechanism is said zoom lens, and said object detecting apparatus further comprises:

means for changing manually said focal distance of said zoom lens and a display for displaying said input image, wherein an operator operates said zoom lens as viewing said input image on said display.

12. An object tracking method for tracking an object in comparison between an input image from an image pick-up device having a zoom mechanism and a template image stored in memory said object detecting method comprising the steps of:

storing a first image within a view field of said image pick-up device as said template image;

picking-up a second image to be detected from said image pick-up device;

recording a power of said zoom mechanism to be changed;

changing a size of either one of said template image and said second image on the bases of said changed power of said zoom mechanism;

performing a template matching between said template image and said second image to detect said object; and

controlling a moving mechanism of said image pick-up device in accordance with the results of said template matching so as to track said object,

wherein the step of recording a power of said zoom mechanism to be changed comprises the steps of;

storing a first focal distance of said zoom mechanism at a time when said template image is picked-up, and

detecting a second focal distance of said zoom mechanism at a time when a second image from said image pick-up device is picked-up.

13. An object tracking method according to claim 12, wherein said step of storing said first image as said template image comprises the steps of:

setting an area having a predetermined size containing said object and controlling said zoom mechanism so that said object is included in said area.

14. An object tracking method according to claim 12, wherein said step of performing a template matching is the step of detecting a position of a partial image with a maximum degree of coincidence with said template image from said second image from said image pick-up device.

15. An object tracking method according to claim 14, wherein said step of controlling a moving mechanism of said image pick-up device further comprises the step of:

controlling said moving mechanism so that said object to be tracked positions around of the center of said view field of said image pick-up device.

16. An object tracking method according to claim 12, wherein said zoom mechanism is either one of a zoom lens and an electronic zoom.

17. An object tracking method according to claim 16, wherein said zoom mechanism is said zoom lens, and said object detecting method further comprises the steps of:

changing manually said focal distances of said zoom lens and displaying said input image on a screen of a display,

wherein an operator operates said zoom lens as viewing said input image on said screen.

18. An object tracking method according to claim 16, wherein said zoom mechanism is said zoom lens, the focal distance of said zoom lens is calculated after a passage of time from a predetermined reference time after a zoom control is started.

19. An object tracking method according to claim 12, said object detecting method further comprises the step of:

updating said template image stored to a new template image on the bases of the results to perform a template matching.

20. An object tracking apparatus for tracking an object in comparison between an input image from an image pick-up device having zoom mechanism and a template image stored in memory, said object detecting apparatus comprising:

a storing unit for staring a first image within a view field of said image pick-up device as said template image;

a picking-up unit for picking-up a second image to be detected from said image pick-up device;

a recording unit for recording a power of said zoom mechanism to be changed;

a first control unit for changing a size of either one of said template image and said second image on the bases of said changed power of said zoom mechanism;

a processing unit for performing a template matching between said template image and said second image to detect said object; and

a second control unit for controlling a moving mechanism of said image pick-up device in accordance with the results of said template matching so as to track said object,

wherein said recording unit for recording a power of said zoom mechanism to be changed stores a first focal distance of said zoom mechanism at a time when said template image is picked-up and detects a second focal distance of said zoom mechanism at a time when a second image from said image pick-up device is picked-up.

21. An object tracking apparatus according to claim 20, wherein said first control unit controls said zoom mechanism so that said first image as said template image includes an area having a predetermined size containing said object and said object is included in said area.

22. An object detecting apparatus according to claim 20, wherein said zoom mechanism is either one of a zoom lens and a an electronic zoom.

23. An object detecting apparatus according to claim 22, wherein said zoom mechanism is said zoom lens, and object detecting apparatus further comprises:

means for changing manually said focal distances of said zoom lens and a display for displaying said input image, wherein an operator operates said zoom lens as viewing said input image on said display.