| 摘要 |
PURPOSE:To obtain a result of measurement with high accuracy and at a high speed by measuring the optical accuracy of flatness and perpendicularity of a roof mirror based on an amplitude modulation function related directly to picture information. CONSTITUTION:In case each flatness of a roof mirror 7 is lowered, a spectrum pitch becomes equivalently narrower than the case when it is optically flat, and a descent curve of an amplitude modulation function following an increase of a space frequency becomes steep. Accordingly, each flatness is evaluated by its descent characteristic. As for each perpendicularity of each reflecting surface 8, 10 of the roof mirror 7, its perpendicularity is evaluated by the magnitude of each deflection of the respective image forming positions M1, M2 of a peak value LM1 of a signal level corresponding to one reflecting surface 8 shown in the figure, and a peak value LM2 of a signal level corresponding to the other reflecting surface 10. In this way, the optical accuracy of flatness and perpendicularity of the roof mirror can be measured based on an amplitude modulation function related directly to picture information, therefore, a result of measurement is obtained with high accuracy and at a high speed. |
