Image tracking apparatus

• US 5,706,362 A
• Filed: 10/11/1996
• Issued: 01/06/1998
• Est. Priority Date: 03/31/1993
• Status: Expired due to Term

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Yabe, Sanae
• Primary Examiner(s): Boudreau, Leo
• Assistant Examiner(s): SHALWALA, BIPIN H
• Application Number:
  US08/729,423
• Time in Patent Office: 452 Days
• Field of Search: 382/100, 382/103, 382/209, 382/218, 382/254, 382/274, 382/275, 382/278, 348/129, 348/130, 348/169, 348/170, 348/148, 348/149, 348/152, 348/153, 348/154, 348/701
• US Class Current: 382/103
• CPC Class Codes: G01S 3/7865 using correlation of the live video image with a stored image
• 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 10/255 Detecting or recognising potential candidate objects based on visual cues, e.g. shapes
• CPC Class Codes: G06V 20/56 exterior to a vehicle by using sensors mounted on the vehicle
• CPC Class Codes: G06V 2201/08 Detecting or categorising vehicles
• CPC Class Codes: H04N 23/61 based on recognised objects
• CPC Class Codes: H04N 23/635 Region indicators; Field of view indicators

Abstract

An image tracking apparatus includes a video camera 10 for forming an image of a target vehicle and for producing image signals at predetermined time intervals, a first memory 5A for storing image signals, a window setting switch 9 for setting a tracking window on the image signals which were stored in the first memory, a second memory 6A for storing, as reference image signals, the image signals on which the tracking window has been set, a device 11 for detecting whether or not any disturbance has been introduced into the image signals stored in the first memory, and a device 12 for correcting by interpolation the image signals stored in the first memory to reduce the influence of any disturbances. A window updating device updates the tracking window in accordance with a comparison between the reference image signals stored in the second memory and the image signals stored in the first memory, or, when a disturbance has been introduced, in accordance with a comparison between the reference image signals stored in the second memory and the corrected image signals.

Claims

1. An image tracking apparatus comprising:

a) image means for forming successive images of a target to be tracked and for producing corresponding image signals based on the formed images at predetermined time intervals;

b) a first memory for storing both currently sensed image signals and previously sensed image signals produced by said imaging means;

c) window setting means for setting a tracking window on the previously sensed image signals which were stored in said first memory a predetermined time before;

d) a second memory for storing, as reference image signals, the previously sensed image signals on which said tracking window has been set by said window setting means;

e) disturbance detecting means for detecting whether or not any disturbance has been introduced into the currently sensed image signals stored in said first memory;

f) correcting means for correcting, when said disturbance detecting means has detected that the disturbance has been introduced, said currently sensed image signals stored in said first memory in such a manner as to reduce the influence of said disturbance; and

g) window updating means for;

i) updating said tracking window in accordance with a comparison between the reference image signals stored in said second memory and the currently sensed image signals stored in said first memory when said disturbance detecting means has detected that no disturbance has been introduced, and

ii) updating said tracking window in accordance with a comparison between said reference image signals stored in said second memory and the currently sensed image signals which have been corrected by said correcting means when said disturbance detecting means has detected that a disturbance has been introduced.

2. An image tracking apparatus according to claim 1,

wherein each image frame of said image signals corresponding to said successive images produced by said imaging means includes a first field and a second field;

and

wherein said disturbance detecting means detects whether a disturbance has been introduced, based upon the result of a comparison between said first and second fields of said currently sensed image signals produced by said imaging means.

3. An image tracking apparatus according to claim 2,

wherein said correcting means includes:

field detecting means for detecting one of said first and second fields of said currently sensed image signals which has been less affected by the disturbance; and

interpolation means for interpolating, using the currently sensed image signals of the field which has been detected by said field detecting means as having been less affected by the disturbance, the currently sensed image signals of the other field.

6. An image tracking apparatus according to claim 1, wherein said disturbance is an optical obstruction disposed between said target and said imaging means.

7. An image tracking apparatus according to claim 1, wherein said imaging means is disposed on a platform and said disturbance is caused by vibration of said platform.

8. An image tracking apparatus according to claim 7, wherein said platform is a vehicle.

4. An image tracking apparatus comprising:

a) image means for forming successive images of a target to be tracked and for producing corresponding image signals based on the formed images at predetermined time intervals;

b) a first memory for storing both currently sensed image signals and previously sensed image signals produced by said imaging means;

c) window setting means for setting a tracking window on the previously sensed image signals which were stored in said first memory a predetermined time before;

d) a second memory for storing, as reference image signals, the previously sensed image signals on which said tracking window has been set by said window setting means;

e) window updating means for updating the tracking window in accordance with a comparison between the reference image signals stored in said second memory and the currently sensed image signals stored in said first memory;

f) disturbance detecting means for detecting whether or not any disturbance has been introduced into the currently sensed image signals stored in said first memory; and

g) update prohibiting means for prohibiting the updating of said tracking window by said window updating means when the introduction of a disturbance is being detected by said disturbance detecting means.

5. An image tracking apparatus according to claim 4, further comprising:

tracking suspension means for suspending the entire tracking operation when the period of prohibition of updating by said update prohibiting means has exceeded a predetermined time.