EP0290140A2
Expired / Lapsed
EP
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Equipment for measuring differences in elevation
Assignee: Optec Co Ltd
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Filing: 1988-04-08
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Granted: —
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Expires: 2008-04-08
Abstract
Abstract Surveying equipment for measuring differences in elevation employs a leveling pole (1) and a level. The leveling pole (1) carries division marks formed by coded marks spaced at unit height intervals. The level comprises a telescope (4,6) and an image sensor (9). The output signal of the sensor (9) is decoded for display of digital height values. A thick plate glass block (21) in front of the object lens (4) can be tilted for vertical compensation of the optical axis of the telescope. The angle of inclination (ϑ) of the plate glass block (21) required for compensation is used for interpolation between two adjacent coded marks.
Inventors
- 👤 Yoshinori Narutaki
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 17:16
CPC Classifications
G; G01; G01C; G01C5/00; G01C15/00; G01C15/02; G01C15/06
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
100 words
A level for measuring differences in elevation comprising: a telescope having an optical system (4,6) and leveling (5) means for leveling the telescope, characterised by an image sensor (9) added to the optical system the sensor (9) having a linear image pickup line (30) directed to read, is use, an image of one of a set of coded height marks (2) provided at unit intervals on a leveling pole (1) to digitally indicate heights; and by decode means (13) coupled to the output of said image sensor (9) for decoding the imaged coded mark to form a digital height signal.
Claim 2
Dependent Claim
100 words
A level for measuring differences in elevation comprising: a telescope having an optical system (4,6) and leveling (5) means for leveling the telescope, characterised by an image sensor (9) added to the optical system the sensor (9) having a linear image pickup line (30) directed to read, is use, an image of one of a set of coded height marks (2) provided at unit intervals on a leveling pole (1) to digitally indicate heights; and by decode means (13) coupled to the output of said image sensor (9) for decoding the imaged coded mark to form a digital height signal.
Claim 3
Dependent Claim
17 words
A level according to claim 1, characterised by display means (14) for digital indication of height values.
Claim 4
Dependent Claim
48 words
A level according to claim 1 or 2, characterised in that the said telescope optical system comprises an eyepiece (6c), for aligning the optical axis thereof with the leveling pole, and a beam splitter (7) for dividing incident rays between the eyepiece (6c) and the image sensor (9).
Claim 5
Dependent Claim
64 words
A level according to any of claims 1 to 3, characterised in that the leveling means is an automatic optical level system comprising a pendulum mirror (5c,5d), a first fixed prism (5a) for directing incident rays onto a reflecting surface of the pendulum mirror (5c) and a second fixed prism (5b) for directing rays reflected by the mirror (5c) onto the image sensor (9).
Claim 6
Dependent Claim
69 words
A level according to any preceding claim, characterised by a micro optical system (20) in front of the object lens (4) of the telescope optical system for vertical compensation of the optical axis thereof, the micro optical system comprising a glass plate (21) having parallel planes and tilting means (22-26) for inclining the glass plate (21) about a horizontal axis (21a) normal to the optical axis of the telescope.
Claim 7
Dependent Claim
105 words
A level according to claim 5, characterised by means (27) for detecting the inclination angle of said glass plate (21), vertical edge detecting means for detecting at least one vertical edge of the coded mark in accordance with the output of said image sensor (9) and an interpolator for calculating an interpolated height value in accordance with a decoded signal from said decode means and an angle data from said angle detecting means (27) obtained at an inclined position where said edge detecting means detects a condition that the optical axis of said telescope aligns with one of vertical edges of the said coded marks.
Claim 8
Dependent Claim
28 words
A level according to claim 6, characterised in that the angle detecting means comprises a rotary encoder (27) coupled to the tilting means for the glass plate (21).
Claim 9
Dependent Claim
47 words
A level according to claim 6, characterised in that the angle detecting means comprises a pulse motor coupled to the tilting means so as to incline the glass plate and a pulse counter which counts the drive pulses of said pulse motor to generate inclination angle data.
Claim 10
Dependent Claim
112 words
A level according to any preceding claim, characterised in that the image sensor (9) comprises an array of light-receiving elements (30) extending in a direction which in use is aligned with the images of said coded marks (in a widthwise direction of a leveling pole), and has a sufficient resolution for reading the smallest image of said coded marks at a maximum distance within a predetermined measurable range between said level and a leveling pole, and a length of said light-receiving element array (or the number of elements) is sufficient for allowing said image sensor to read the largest image of said coded marks at the minimum distance within the measurable range.
Claim 11
Dependent Claim
89 words
A level according to any preceding claim, further characterised by means for detecting a length of an image on the sensor surface (9) on the basis of an output from said image sensor, means for calculating a horizontal distance between said level and a leveling pole on the basis of the length of a coded mark on said leveling pole corresponding to that of its image, and of the magnification of the telescope from the object lens to the sensor surface, and means for displaying the calculated horizontal distance.
Claim 12
Dependent Claim
33 words
A leveling pole for use in measuring differences in elevation, the pole carrying divisions at unit intervals from one end of the leveling pole, characterised in that the divisions comprise coded marks (2).
Claim 13
Dependent Claim
33 words
A leveling pole for use in measuring differences in elevation, the pole carrying divisions at unit intervals from one end of the leveling pole, characterised in that the divisions comprise coded marks (2).
Claim 14
Dependent Claim
23 words
A leveling pole according to claim 11, characterised in that the divisions are vertical edges of the mark pattern of the coded marks.
Claim 15
Dependent Claim
52 words
A leveling pole according to claim 11 or 12, characterised in that each of said coded marks comprises a height code (22) and an identfication code (21) which is distinguished in digital bit pattern from disturbing environmental images when the coded mark is picked up by an image sensor and decoded thereafter.
Claim 16
Dependent Claim
35 words
A leveling pole according to any of claim 11 to 13, characterised in that each of the coded marks (2) is a bar code mark comprising marks and spaces arranged horizontally on the pole surface.
Claim 17
Dependent Claim
28 words
Equipment for measuring differences in elevation comprising a level according to any of claims 1 to 10 and a pole according to any of claims 11 to 14.
References Cited (Backward Citations)
No citation records indexed.
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