| 摘要 |
PURPOSE:To enable the measurement of an angle of inclination in all kinds of street structure by comparing a video signal of a picture whose center corresponds to a point on a circle defined with a fixed distance from the origin as radius thereof with a video signal of a picture at the origin to determine a peak in the evaluation value when they coincide with each other. CONSTITUTION:A camera apparatus which has the center 0 of a picture at the origin (X0, Y0) on the abscissa X and the ordinate y is provided to convert signals corresponding to one picture A into for example binary coded signals to be memorized. Then, a video signal of a picture B whose center point corresonds to a point (X1, Y1) determined on a circle (a) which is defined with its radius equivalent to integral times a large as a pitch P1 in the lateral way (in the direction X) of a rectangular pattern on a wafer with the origin (X0, Y0) as its center is compared with signals of the picture A at the origin. A evaluation value G is memorized when they coincide with each other and then, evaluation values G are memorized sequentially as the center 0 of the picture are moved on the circle (a) at a specified pitch. In this manner, the inclination level of the wafer is measured based on the angle theta between the line joining values on the ordinate Y and the abscissa X at the peak of the evaluation value G. |
