| 摘要 |
PURPOSE:To determine the midpoint of the first and last values of those addresses which exceed the clamping level each time a rosette scanning is made when video signals in an infrared range obtained by the scanning is clamped and then, calculating a geometric means of the addresses over one field to make a tracking point. CONSTITUTION:Video signals supplied from a rosette scanner 3 are clamped with a clamping circuit 7. Then, regarding the addresses which exceed the clamp ing level as to the video signal, the first value is memorized in a memory of an X axis address detection circuit 10x using a timing signal generated by a first address detection circuit 8 and the last value in a memory of a Y axis address detection circuit 10Y using a timing signal generated by a last address detection circuit 9. Likewise, X axis addresses and Y axis addresses over scannings (n) times are stored in the memories and inputted into a geometric means circuit 11 following one field to output the address X and Y of the tracking point. This can reduce the effect of background objects other than the target assuring a stable and a highly accurate tracking. |
