JPS623610A - Measuring method and measuring device for determining relative position between two object - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical measurement method and an optical measurement device, in particular a device for remotely reading barcodes.

Techniques for non-contact measurement of the relative position of three mutually movable parts are needed in a variety of fields.

Both parts may be parts of precision machinery whose position is to be determined by high A-level accuracy or by a diamond gauge, for example reading optics. In this way, for example, conventional readings (reading at a high point on a leveling rod at a distance) using a level or level IC connected telescope or television camera have to be read.

However, reading the reading scale of a remote noisy location using a telescope requires a high degree of concentration from the observer. However, with this method, the error in picking the bladder always occurs when the observer is inexperienced.

Studies have been conducted to eliminate high sensitivity to known levels of error in various ways. The reading of the leveling rod will be replaced by the receiver previously used.

However, leveling rods are very complex and are practically unsuitable for rough use in the field or on debris sites. In addition to this, measuring with this leveling rod is disadvantageous and requires a lot of effort.

According to Australian Patent No. 2542777 K, the leveling rod is provided with a combination of black and white vertical stripes and triangles. By scanning these marks the leveling rod is scanned at right angles to the leveling rod and by selecting the appropriate code. A value is required. However, in this case the limited lateral accuracy and low sensitivity associated with reading leveling rods separated by long distances are very disadvantageous.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a level, consisting of a level 1 and a leveling rod 2 set at a distance 2 from the level 1.

According to a preferred embodiment, the horizontal barcode 3 is
Level 1 is used to read leveling staff 2.

In FIG. 2, level 1 includes an objective lens 4, a prefocusing lens 5 with a cooperating focusing drive mechanism, a beam splitter 7, a crosshair 8 and an eyepiece 9. A detector group 10 is located near the beam split from the chief ray by the beam splitter 7. The detector group 10 has a transducer which scans the element perpendicularly to the optical axis and is used for rounding to generate electrical signals in accordance with conventional methods.

The arrangement is such that the code elements of the leveling rod 2, which are incident on the objective lens 4, are aligned in the plane of the detector group 10. The signal processing device 11 shown in FIG. 3 is connected in series with the detector group 10.
1, the signal of the detector Q in the detector group 10 is transmitted to the amplifier 12,
The signal is inputted to a computer 15 via sampling and holding means 13 and an analog-to-digital converter 14.

A measurement result display device 16 is connected to the output side of the computer.

A position detector 17, for example a displacement transducer or an angle detector coupled to a rotary knob, is connected to the focus adjustment drive 6 of the novel.

This device 17 allows the device to determine the position of the focusing drive mechanism when it is focused on the leveling rod. The output signal of the position detector 17 is input to the computer 15 as another input signal.

ROMI 8 is connected to the computer 15.
, ROMVC stores a reference code corresponding to the bar code on the leveling rod.

The computer determines the position of the code height on the leveling rod, and therefore the level height, by comparing the code produced by the detector group 10 with the reference code stored in the FjOMl 8 in a manner described in detail later, in practice. The above leveling operation consists of pointing the leveling rod 2 with the level 1 telescope and adjusting the focus adjustment drive mechanism 6.

From the focus position of the telescope, input by the position of the detector 17, the computer first determines the distance 2 between the level 1 and the staff 2. For this purpose, the ROM 18 contains corresponding calibration constants that depend on the distance ZK as a function of the focus position.

Based on the focal length of the telescope objective and the preset distance z between the level 1 and the leveling rod 2 which are also stored preferably in the ROM 18, the computer 15 calculates the equation m=-ψ
Calculate my magnification accordingly.

The leveling rod 2 is focused on the detector group 10 at this image magnification.

The operation of the signal processing device 11 as the selected next side will be explained with reference to Figures 4 to 40.

The signal for the 4th RAM company reference code R(ram, Δ) is shown in the plane of the detector group 1o and is shown in this plane for readout from the ROM 18 and for ease of understanding. is shown as a function of the individual detector DiO position γ within. Thus, γ is variable, while the magnification m can be considered as a parameter. Δ is also a parameter and shows the relative relationship of the start position of the code to the start position of the individual detector elements, corresponding to FIG. 4B.

The choice of code designation or detector arrangement is such that the distance Δ is always smaller than the detector spacing h' between two adjacent ratio detector elements D1 (see FIG. 4B).

As a function of the position r, FIG. 4B shows the individual detector elements p1
(γ), i-1, 2,...N sensitivity -41D(γ)
shows.

By means of a correspondingly selected control program, the computer 15#i assigns a reference code R(γ; m, Δ
) and integrate it over the position rK.

The result is the discontinuous value P1P2 etc. (
m, △).

P, (m, △)'w f: R(ram, △) -DI
The (r)·dr sensitivity curve DI(γ) is then replaced by the detector spacing hc by suitable computer operations and multiplied by R(γ:m, Δ) and integrated O second discrete value P2 (m , Δ) are obtained by this operation.

This process is repeated until the complete reference code is covered. The results are represented diagrammatically in FIG. 4C. In a program-controlled manner, the computer 15 finally calculates the intensity Q1 measured by the individual detection elements DiK in the detector group 10, Discriminated reference value P1
The cross-correlation between (m+Δ) KL (m,Δ) is determined by the following formula, where N is the number of detector elements used.

Based on the value of the cross-correlation function thus calculated, the computer performs the replacement by a predetermined maximum value of the cross-correlation in a program-controlled manner. Parameter m
and Δ are then varied by a mathematical method and the maximum value of the cross-correlation function Kra(m, Δ) is determined as a function of m and Δ.

From the values of m and Δ, the group of values having the greatest correlation is selected, and the reading position, ie, the level height in this embodiment, is calculated from the corresponding parameters.

For the first determination of the distance between level 1 and staff 2, the accuracy ΔVz is obtained based on the following formula:

△Z/Z −OPD, 8-Z/D”Di level 1 objective lens aperture, OPD is the optical phase difference. If we assume OPD≦λ/2 and D=4σn, the relative distance accuracy ΔZ/Z is better than ±14 for 2-100 m and better than ±0.7% for Z=5 m.

In order to be suitable for the described use and process, the barcode 3 must fulfill the following conditions:

The image magnification of leveling rod 2 is the distance Dll between level 1 and leveling rod 2 (
Therefore, since it changes on the plane of the detector group, the image magnification m undergoes a considerable change.For example, when changing the distance 2 from 1.5 to 100 m, the image magnification changes by a factor of 66.6.

The individual elements D1 of the detector group 10 have a limited spacing from each other, so that the projection of the code elements onto the detector elements must be much larger than the mutual spacing h1 of the detector elements.
The detector elements can then resolve the code.In this way, based on the Nyquist theory derived from communications engineering, the projection of the code element G1 is at least 2 times the distance hl between the detector elements. Should be double.

This condition is such that the size of the code grating 5 selected for the leveling staff 2 is G≧2h'm, where m is the maximum measuring distance ZK of the leveling staff in the plane of the detector group 10 versus the image magnification. be.

If the distance 2 between the repe y1 and the leveling rod 2 is short, a practical detector for the telescope, the ninth reduction in the number of elements, the field of view will be reduced to a few grating elements G in the field of view of the detector group 10. The less L it is, the narrower it becomes. This number of grid elements is so small that unambiguous identification of the code information and therefore unambiguous and accurate reading of the code carrier is insufficient. To solve this problem, in such a case, a variable focal length optical system, such as a zoom lens or a magnification converter, is used at level 1 in an embodiment of the invention. A field scanning device is suitable for this purpose. Another solution to the above problem is to subdivide the grid elements of the code, either light or dark, or both, by means of a precision grid system, resulting in a finer-grained code.

This fine code cannot be read by the detector group 10 at a distance of 2 and is instead interpreted as a gray value. For short A distances 2, the thin cord helps determine the position on the detector group when the field of view is limited to A. The cord grid has been proven to be suitable for embedded cords, and the coarse lattice is approximately 1.5 times the size of the line spacing on the cord carrier for the actual maximum measuring distance 2@code The carrier can have any shape that can be determined by the scanning device, for example the code carrier can be circular.

This makes it possible to automatically and very precisely scan the angular position of the component connected to the code carrier. The necessary calculation operations are simplified in that, if the distance between the code carrier and the reader is determined, the image magnification m can be considered as a determined quantity with respect to the optical system.

The computer-implemented comparison operations in the plane of cross-correlation described in the preferred embodiment may consist of any integral comparison operations. Many or most of the detector elements on which the code pattern is imaged are used for comparison with the reference code.

Although the present invention has been described in detail above, this detailed description is by way of example only, and the scope of protection is limited only by the spirit of the invention and the scope of the claims.

Instead of the signal emitted as described above in relation to the level on the leveling rod 2 from the position signal, it is also possible to use the same signal associated with a specific position and for the direct measurement of the nine-angle position. For example, the leveling rod 2 may be connected to a rangefinder section at a specific location, or the associated code pattern may be fixed directly to such a section.

This part moves in a direction parallel to the code pattern axis.
In some cases, it is possible to directly calculate the angle corresponding to the displacement of said part with respect to a previous position or a previously specified reference.

[Brief explanation of drawings]

Figure 1 shows details of the barcodes along the leveling rods and the leveling rods spaced apart; Figure 2 is a cross-sectional view of the level in Figure 1; Figure 3 shows the connection to the replets in Figure 1. 4 is a block diagram of the evaluation and display system, and FIG.

Claims (29)

[Claims] (1) A measuring device for determining the relative position between a first part and a second part, the first part and the second part being movable relative to each other, the first part being a cord carrier, the cord a one-dimensional code pattern disposed on the carrier, the second part comprising optical means for remotely reading the code pattern, a code reader for converting the image of the code pattern into a signal, and a code reader for converting the image of the code pattern into a signal; a computer for receiving, the computer having means for storing information corresponding to said code pattern, and said computer having means for storing information corresponding to said code pattern and said signal and a corresponding portion of the stored information for determining relative position. A measuring device characterized in that it has means for comparing. 2. Measuring device according to claim 1, wherein both parts are movable relative to each other by a translational or rotational movement and have means for arranging a one-dimensional code on the code carrier. (3) the second portion has means for determining a horizontal distance between the first portion and the second portion; and means for reading a code pattern for determining a vertical distance between the first portion and the second portion; 2. A measuring device according to claim 1, further comprising means for modifying said code pattern signal in dependence on the measured horizontal distance. (4) The measuring device according to claim 1, wherein the computer is configured to digitize the signal from the code reader and to perform an integral comparison between the signal and a stored reference code. . (5) The measuring device of claim 1, wherein the computer performs a cross-correlation comparison between the signal and the stored information. (6) The measuring device according to claim 1, wherein the code reader includes a group of detectors arranged in an imaging plane. (7) The measuring device according to claim 1, wherein the code reader is connected to means for time-delayed scanning. (8) The computer is adapted to modify the stored information by the sensitivity of the detector group, and the computer has a comparator for comparing said signal with the signal obtained from this operation. Measuring device according to scope 6. (9) The measuring device according to claim 1, wherein the code pattern consists of at least one coarse code and at least one fine code. (10) The optical system has a telescope, and the telescope has a focus adjustment drive mechanism connected to a position detection means, and means for inputting the output of the position detection means to a computer. measuring device. (11) the code pattern consists of at least one coarse code and at least one fine code, such that the device uses the coarse code to measure relatively long distances and the fine code to measure relatively short distances; 2. A measuring device according to claim 1, which can be used to: (12) The measuring device according to claim 11, wherein the code pattern is selected such that after digitization it retains the quasi-stochastic properties necessary for decoding. (13) The measuring device according to claim 1, wherein the second part consists of a level and the first part consists of a leveling rod. (14) The measuring device according to claim 1, wherein the device is used as a distance meter. (15) The measuring device according to claim 1, wherein the device is used as a clinometer. (16) A method for measuring a relative position between a first part and a second part, wherein the first part and the second part are movable relative to each other, the method comprising: providing a cord carrier on the first part; , arranging a one-dimensional code pattern on the code carrier; remotely reading the code pattern using an optical system in a second part; using a code reader to convert the image of the code bar pattern into a signal; using a computer to receive said signal; causing the computer to store a signal corresponding to the code pattern and to determine relative position; and comparing said signal with a corresponding portion of said stored information. A method for measuring relative position characterized by using a computer. 17. The method of claim 16, wherein the image magnification of the stored information is derived from a distance measurement between the code carrier and the code reader and is input into the calculation process. (18) using optimization calculations controlled by a computer program by varying the image magnification of the reference code and the relative position to the detector element in the second part;
Claim 1 determining the maximum value of the cross-correlation function
The method described in Section 6. (19) A coarse distance measurement between the code carrier and the code reader is performed and a first image magnification is calculated in order to generate a reference code corresponding to the stored information for optimization purposes. The method according to item 16. 20. The method of claim 16, wherein both parts are movable relative to each other by translation or rotation and a one-dimensional code is correspondingly arranged. (21) determining the horizontal distance between the first part and the second part;
17. The method of claim 16, wherein the code pattern is read to determine the vertical distance between the first part and the second part, and the code pattern signal is modified depending on the predetermined horizontal distance. (22) The method according to claim 16, wherein the code pattern reading is performed by time-delayed scanning. (23) The code reader has a group of detectors arranged in the image plane, modifies the stored information by the sensitivity of the group of detectors, and compares the signal obtained from this operation with said signal in the computer. , the method according to claim 16. (24) The code reader has a group of detectors arranged in the image plane, and reads the reference code in the computer as necessary.
17. The method of claim 16, wherein the detector spacing is replaced by a fraction. (25) At least one of the two parts comprises an optical system, the optical system comprises a telescope, and the telescope comprises a focus adjustment drive mechanism connected to a position detection means, and means for inputting the output of the position detection means to a computer. 17. The method of claim 16, comprising: (26) At least one of the two parts is an optical system, the code pattern includes at least one coarse code and at least one fine code, the coarse code is used to measure a relatively long distance, and the fine code is used to measure a relatively long distance. 17. A method as claimed in claim 16, comprising measuring a relatively short distance. (27) The method according to claim 26, wherein after digitizing the coarse code and the fine code, the fine code pattern and the coarse code pattern are set so as to retain quasi-stochastic characteristics necessary for decoding. (28) The method according to claim 16, wherein at least one of the two parts has an optical system, and the at least one part having the optical system is used as a range finder. (29) The method according to claim 16, wherein at least one of both parts has an optical system, and the at least one part having the optical system is used as a clinometer.