Object tracking method and object tracking apparatus

• US 20050018879A1
• Filed: 07/22/2004
• Published: 01/27/2005
• Est. Priority Date: 07/22/2003
• Status: Active Grant

• Current Assignee: Hitachi Kokusai Electric Incorporated (Hitachi, Ltd.)
• Original Assignee: Hitachi Kokusai Electric Incorporated (Hitachi, Ltd.)
• Inventors: Ito, Wataru, Fujii, Miyuki
• Granted Patent: US 7,596,240 B2
• Time in Patent Office: Days
• US Class Current: 382/103
• CPC Class Codes: G01S 3/781 Details
• 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 13/19652 Systems using zones in a single scene defined for different treatment, e.g. outer zone gives pre-alarm, inner zone gives alarm
• CPC Class Codes: G08B 13/19686 Interfaces masking personal details for privacy, e.g. blurring faces, vehicle license plates
• 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
• CPC Class Codes: H04N 7/183 for receiving images from a single remote source

Abstract

An object tracking apparatus consisting of an imaging device, a signal processor for processing a video signal generated by the imaging device, and a display for displaying the result of processing performed by the signal processor. An intruding object is detected within a field under monitoring based on a video signal captured by the imaging device, and the imaging device is controlled in response to motions of the intruding object to track the object. The position of a visual field range of the imaging device is calculated, and panning and tilting of the imaging device and an imaging lens are controlled such that the calculated position of the visual field range of the imaging device does not include an imaging prohibited region positioned within the field under monitoring.

Claims

1. A tracking method for tracking an object using an imaging device configured for controlling at least one of an imaging direction and zooming, said method comprising the steps of:

detecting the object based on an image from said imaging device;

calculating a current or a predicted visual field range of said imaging device;

determining whether or not the current or predicted visual field range includes an imaging prohibited region;

controlling at least one of the imaging direction and zooming of said imaging device based on detected information of the object when the current or predicted visual field range does not include an imaging prohibited region; and

tracking said object.

2. A method according to claim 1, further comprising the step of stopping the operation of said imaging device when the calculated or current visual field range includes an imaging prohibited region.

3. A method according to claim 1, further comprising the step of operating said imaging device in an opposite direction for a predetermined time and stopping the operation of said imaging device when the calculated or current visual field range includes an imaging prohibited region.

4. A method according to claim 1, further comprising the step of masking an imaging prohibited region included in a captured image when the captured image of the calculated current or predicted visual field range includes the imaging prohibited region.

5. A method according to claim 1, further comprising the step of displaying a message which indicates that operation of said imaging device is stopped because said imaging prohibited region is detected.

6. A method according to claim 1, wherein said step of calculating the predicted visual field range of said imaging device includes the steps of:

calculating a moving amount of said imaging device based on a positional relationship between a current position of the object and a predetermined position within the image; and

calculating the predicted visual field range based on a control amount of said imaging device including the moving amount.

7. A method according to claim 1, further comprising the step of, when said current or predicted visual field range includes said imaging prohibited region, calculating a visual field range that does not include said imaging prohibited region and controlling at least one of the imaging direction and zooming of said imaging device based on the calculated visual field range.

8. A method according to claim 1, further comprising the step of making the focal length of said imaging device longer by a predetermined amount when said current or predicted visual field range includes said imaging prohibited region.

9. A tracking method for tracking an object using an imaging device configured for controlling at least one of an imaging direction and zooming, said method comprising the steps of:

detecting the object based on an image from said imaging device;

calculating a current or a predicted visual field range of said imaging device;

determining whether or not the current or predicted visual field range includes an imaging prohibited region;

controlling at least one of the imaging direction and zooming of said imaging device based on detected information on the object when the current or predicted visual field range includes an imaging prohibited region; and

tracking said object.

10. A method according to claim 9, further comprising the step of returning said imaging device toward an essential region when the calculated or predicted imaging range does not include the essential region.

11. An object tracking apparatus comprising:

an imaging device;

a driving mechanism coupled to said imaging device for changing the position of a visual field range of said imaging device;

an image signal processor for processing an image signal from said imaging device; and

a controller for controlling said driving mechanism in response to a control signal from said image signal processor,

wherein said image signal processor includes;

means for detecting an object based on an image from said imaging device;

means for calculating a current or a predicted visual field range of said imaging device;

means for determining whether or not the calculated current or predicted visual field range includes an imaging prohibited region; and

means responsive to said determining means for generating the control signal for controlling at least one of the imaging direction and zooming of said imaging device based on detected information on the object when said determining means determines that the calculated current or predicted visual field range does not include an imaging prohibited region.

12. An apparatus according to claim 11, wherein said driving mechanism includes a zooming controller for controlling the zooming of said imaging device, and a pan head controller for controlling the imaging direction of said imaging device.

13. An object tracking apparatus comprising:

an imaging device;

a driving mechanism coupled to said imaging device for changing the position of a visual field range of said imaging device;

an image signal processor for processing an image signal from said imaging device; and

a controller for controlling said driving mechanism in response to a control signal from said image signal processor,

wherein said image signal processor includes;

means for detecting an object based on an image from said imaging device;

means for calculating a current or a predicted visual field range of said imaging device;

means for determining whether or not the calculated current or predicted visual field range includes an imaging prohibited region; and

means responsive to said determining means for generating the control signal for controlling at least one of the imaging direction and zooming of said imaging device based on detected information on the object when said determining means determines that the calculated current or predicted visual field range includes an imaging prohibited region.

14. An apparatus according to claim 13, wherein said driving mechanism includes a zooming controller for controlling the zooming of said imaging device, and a pan and tilt head controller for controlling the imaging direction of said imaging device.