1. Field of the Invention
The present invention relates to an automatic surveying system which can electrically read a scale indicated on a graduated face of a level rod, a staff, or a rod, etc., mainly used for leveling.
2. Description of the Related Art
For a leveling operation, various kinds of levels are known, such as a digital level or an electronic level which electrically reads a scale of a level rod. In a digital level, a special-purpose staff coated with special codes is incorporated in a measuring system, so that an image of the special codes formed on the staff is picked-up by a collimating telescope and an electronic image pickup device. Image data of the picked-up image is analyzed by an analyzing device such as a micro computer to measure and indicate a level or distance.
However, in a conventional digital level, if a general-purpose staff (available on the market) is used, it is impossible to analyze or distinguish the scale or numbers indicated on the general-purpose staff. Therefore, the level or distance cannot be automatically read using a staff other than the special-purpose staff. If the special-purpose staff is used, visual survey through an eyepiece of the collimating telescope of the digital level cannot be carried out.