| 摘要 |
PURPOSE:To enhance the precision of determination of the reference position by a method wherein wind regions are set through selection of positions suitable for determination of coordinates in X and Y directions in view of the shape of the picture, and coordinates are determined by making use of binary-coded scanning output signals. CONSTITUTION:A wind region W2 (a,b,c,d) is set at a position suitable for determination of Y coordinates value, while another wind region W1 (e,f,g,h) is set at a position suitable for the determination of the X coordinates value. In the region W2, the picture 7 is scanned in the X-axis direction for each Y coordinates value, and the lengths of segments of this horizontal scanning are measured. The Y coordinates value YSY of the reference position is determined as the Y coordinates value which is the fourth as counted from the Y coordinates value at which a predetermined threshold value is exceeded from the first time. Then, X coordinates values of the rising points in the wind region W1, along the vertical scanning lines at both sides of a Y coordinates value YDX. The mean value of these X coordinate values is determined as the reference position. |
