| 摘要 |
PROBLEM TO BE SOLVED: To realize auto-focus of a staff without requiring a significant modification of a survey instrument by providing a fine adjustment means for determining the distance to the staff based on a pitch determined by a pitch operating means and moving a focus lens to a position corresponding to the distance. SOLUTION: A line sensor 24 converts the received image of a staff into an electric signal which is amplified through an amplifier 25 and then subjected to sample & hold in synchronism with the clock signal of a clock drive r26. It is then subjected to A/D conversion and stored in an RAM 28. A microcomputer 3 determines the widthwise dimension of each mark based on the signal stored in the RAM 28. Subsequently, the height h of collimation is determined based on the widthwise dimension of the mark and a table value prestored in an ROM 31. A drive circuit 29 controls operation of the line sensor 24. Since the optical axis of a collimation optical system is aligned with that of an image optical system, collimation point on the staff matches that of the image optical system. Survey results are displayed at a display section 32. |
