| 摘要 |
PURPOSE:To realize the automatic tracking device having a high precision and a high stability by estimating the extent of movement of an object in accordance with the inter-field difference of a tracking signal, which is detected at intervals of one or more scanning lines, to make the tracking area follow the object. CONSTITUTION:A focus signal detecting circuit 105 extracts a high frequency component of a certain frequency or higher in the distance measurement area, which is initially set in the center part of the picture, with respect to a luminance signal Y1 of each scanning line and calculates a focus signal V1 corresponding to the in-focus state of a photographic lens 101 with a field period and obtains the position of the peak of the high frequency component in each scanning line. A peak detecting circuit 109 detects a maximum value of the high frequency component of the luminance signal Y1. A lens control part 112 reads in each peak position and obtains the inter-field difference and obtains an average of only inter-field differences in respective scanning lines which are within a preliminarily determined range and estimates the extent of movement in the pertinent field and outputs a signal G1, which moves the distance measurement area by this extent, to a gate circuit. |
