Image tracking apparatus

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.