초록 ▼

A cross-correlation video tracker and method for automatically tracking a relatively moving scene by storing elements from a frame of a video signal to establish a reference frame and comparing elements from a subsequent frame with the stored reference frame to derive signals indicating the directio

A cross-correlation video tracker and method for automatically tracking a relatively moving scene by storing elements from a frame of a video signal to establish a reference frame and comparing elements from a subsequent frame with the stored reference frame to derive signals indicating the direction and angular distance of scene relative movement. A cross-correlation difference signal is generated which represents the difference between a pair of cross-correlation signals dependent on the correlations of the subsequent frame elements and the stored reference elements at two predetermined opposite relative shifts. A circuit is responsive to this difference signal for generating an error signal indicative of the amount of shift required to center the stored reference frame with respect to the subsequent frame. In order to maintain feedback loop stability as the system tracks different scenes which result in varying degrees of decorrelation even with constant shifts in scene position, the circuit responsive to the error signal is also responsive to a gain control signal which represents the difference between a pair of autocorrelation signals dependent upon the correlations of the elements of a representative frame of the video signal at substantially a zero shift and at a fixed predetermined shift. The representative frame of the video signal may be either the subsequent frame or the stored reference frame.

대표청구항 ▼

A device for deriving a signal indicative of the direction and distance of movement between successive video frames, said device comprising: an input for receiving a video signal; means for storing elements from a frame of the video signal to establish a reference; means comparing elements from a su

A device for deriving a signal indicative of the direction and distance of movement between successive video frames, said device comprising: an input for receiving a video signal; means for storing elements from a frame of the video signal to establish a reference; means comparing elements from a subsequent frame of the video signal with the stored reference elements for generating a difference signal representing the difference between a pair of cross-correlation signals dependent on the correlations of the subsequent frame elements and the stored reference elements at two predetermined opposite relative shifts; means for generating a gain control signal; means responsive to the difference signal and to the gain control signal for generating an error signal indicative of the amount of shift required to center the stored reference frame with respect to the subsequent frame; and means for outputting the error signal.