Equipment for measuring a difference in elevation
AssigneeOptec Co., Ltd.
InventorYoshinori Narutaki
Life of this patent
Estimating the term…
Abstract
An equipment for measuring difference in elevation employing a leveling pole and a level is disclosed. The leveling pole comprises divisions of coded marks each indicating height at a unit interval. The level comprises a telescope and an image sensor. The output signal of the sensor is decoded for display of digital height value. A plate glass is provided in front of an object lens for vertical compensation of an optical axis of the telescope. An inclination angle of the plate glass required for compensation is used for interpolation between two adjacent coded marks.
Claims9
A level for use in combination with a leveling pole to be set up at a measuring point, said pole displaying divisions consisting of coded marks each digitally height of mark from an end of said pole at a unit interval, said interval comprising:
- (i) a telescope optical system having an optical axis;
- (ii) leveling means for making the telescope level;
- (iii) an image sensor on which an image is focused by the optical system, said sensor having a linear image pickup device arranged to provide a signal responsive to an image of one of said coded marks;
- said linear image pickup device comprising:
- a light-receiving element array extending parallel to the width of the image of said coded marks, having sufficient resolution for reading the image of said coded marks at a maximum distance of a measurable range between said level and said leveling pole, and wherein the length of said light-receiving element array is sufficient to allow said image sensor to read the image of said coded marks at a minimum distance of the measurable range;
- (iv) a micro optical system provided in front of an object lens of said telescope optical system for vertical compensation of the optical axis thereof, said micro optical system comprising a plate glass having parallel planes facing said object lens and tilting means for inclining said plate glass about a horizontal axis normal to the optical axis of said telescope;
- (v) decoder means coupled to the output of said image sensor for decoding the signal responsive to the image of the coded mark to provide a digital height signal;
- and
- (vi) interpolation means comprising:
- (a) means for detecting he inclination angle of said plate glass, comprising:
- a pulse motor coupled to said tilting means so as to incline said plate glass and means for counting drive pulses of said pulse motor to generate data indicative of said inclination angle;
- (b) detecting means for detecting alignment of the optical axis of the telescope with one of said coded marks in response to the signal provided by said image sensor, as said plate glass is tilted by said tilting means;
- and
- (c) interpolator means for calculating an interpolated height value in accordance with the signal from said decoder means and with angle data from said means for detecting the inclination angle.
Dependencies are inferred from the claim text.