WO2003064971A1 - Method and system for measuring profile of large-area using point diffraction light source based on multilateration - Google Patents
Method and system for measuring profile of large-area using point diffraction light source based on multilateration Download PDFInfo
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- WO2003064971A1 WO2003064971A1 PCT/KR2002/001333 KR0201333W WO03064971A1 WO 2003064971 A1 WO2003064971 A1 WO 2003064971A1 KR 0201333 W KR0201333 W KR 0201333W WO 03064971 A1 WO03064971 A1 WO 03064971A1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
- G01B11/2441—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures using interferometry
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
- G01B11/25—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures by projecting a pattern, e.g. one or more lines, moiré fringes on the object
Abstract
Disclosed are a method and a system for measuring the surface profile of an object having a large-area. The present invention relates to a method and a system for measuring a profile of a surface by obtaining and analyzing interference patterns generated on an object, the patterns of which are formed by installing two-point light sources to the object to be measured. The measuring system includes an optical path changing unit for controlling an optical path of one of the two optical beam sources installed in the optical probe, and a number of (three or six) optical probes disposed according to applied measurement algorithms, thereby measuring the profile of the object.
Description
METHOD AND SYSTEM FOR MEASURING PROFILE OF LARGE- AREA USING POINT DIFFRACTION LIGHT SOURCE BASED ON
MULTILATERATION
Technical Field
The present invention relates to a method and system for measuring a surface profile of an object having any large-area shape, and more particularly, to a method and system for measuring a surface profile of an object by installing two point light sources at the interior of one optical probe, irradiating the point light sources to the object, and analyzing an interference pattern generated from the object.
The inventive measuring system includes an optical path change unit for controlling an optical path of one of the two point light sources installed in the optical probe, and a plurality of optical probes (three or six optical probes) are arranged to measure the profile of the object according to an applied measurement algorithm. Background Art
As a technique for measuring a surface profile of an object having any shape, a multilateration method has been used to determine a position of an aircraft as indicted in FIG. 1, or to determine spatial coordinates of an end of a probe in a three-dimensional measurer as shown in FIG. 2. FIG. 1 illustrates a method for determining a position of an aircraft. Three or more receivers located at any places measure a distance up to the flying aircraft to recognize coordinates of the aircraft (refer to United States Patent No.
6,094,169). FIG. 2 illustrates a three-dimensional measurer for determining coordinates of a measurement probe. Four heterodyne interferometers functioning tracking units track a corner mirror fixed at an end of a moving measurement probe and measure distances from the respective heterodyne interferometers to the corner mirror by receiving light reflected through the corner mirror. Spatial coordinates of the measurement probe at which the corner mirror is located are determined through operations for the measured distances. Although the above-described methods are favorable when determining the coordinate value of only one spatial point, they are not suitable for measuring a surface profile of a measurement target object having any shape. This is because the measurement object should reflect light to the tracking unit at all locations, like the cornet mirror. Then the light emitted from each tracking unit is simultaneously reflected at one point of the measurement object, and a distance from the measurement object to the tracking unit is measured through the received light. Spatial coordinates of that one point are determined through operations for the measured result, and then the above processes are performed for all measurement points of the measurement object.
Moreover, in the above methods, the measurement object having any shape is required to serve as the corner mirror at all coordinates. However, even though this condition is satisfied, the tracking units should measure a distance from all coordinates of the measurement object to each tracking unit and determine spatial coordinates through the operations for the
measured results. Therefore, it is difficult to control the tracking units and equipment becomes complicated. Furthermore, since the amount of operations necessary for calculation is considerable, it takes long time to determine the spatial coordinates. Disclosure of the Invention
Accordingly, the present invention has been made in view of the above-mentioned problems and it is an object of the present invention to provide a measurement algorithm which is capable of simultaneously determining all spatial coordinates of a measurement object having any shape by using a plurality of optical probes each having two point light sources.
It is another object of the present invention to provide a measurement algorithm and measuring system which can apply a plurality of optical probes to remove an error caused by a difference in initial phases of point light sources installed at an optical probe.
To accomplish the objects of the present invention, there is provided a measuring system which can achieve the measurement algorithm, and actual measurement is performed in support of the measurement algorithm. It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
Brief Description of the Drawings
Further objects and advantages of the invention can be more fully understood from the following detailed description taken in conjunction with the accompanying drawings in which: FIG. 1 illustrates a method for determining a position of an aircraft;
FIG. 2 illustrates a three-dimensional measurer for determining coordinates of a measurement probe according to the prior art;
FIG. 3 illustrates a spatial distance from each point light source to any one point (x,y,z) on a measurement object according to the present invention;
FIG. 4 illustrates a method for determining coordinates of any measurement point on a measurement object using six optical probes according to the present invention;
FIG. 5 is a schematic block diagram of a measuring system according to the present invention;
FIG. 6 illustrates a structure of a light source unit of the measuring system according to the present invention;
FIG. 7 is a sectional view of an optical probe comprised of two point light sources according to the present invention; FIG. 8 illustrates a structure of a frame for fixing an optical probe according to the present invention; and
FIG. 8A illustrates locations of a detecting unit and a measurement object on the basis of an optical frame according to the present invention.
Best Mode for Carrying Out the Invention
The present invention will now be described in detail in connection with preferred embodiments with reference to the accompanying drawings.
A measurement algorithm proposed in the present invention will first be explained herein below.
A description will now be made of an algorithm for determining profile coordinates of a measurement object through the analysis of interference patterns generated from three optical probes with reference to FIG. 3.
Definitions of parameters in equations to be expressed later are as follows: k is a wave number(2τr/ l);
I is the light intensity of an interference pattern;
A is the amplitude of light; ri is a spatial distance from a first point light source 111 to any one measurement point 101; r2 is a spatial distance from a second point light source 112 to the measurement point 101; r3 is a spatial distance from a third point light source 121 to the measurement point 101; r4 is a spatial distance from a fourth point light source 122 to the measurement point 101; rδ is a spatial distance from a fifth point light source 131 to the measurement point 101;
i"6 is a spatial distance from a sixth point light source 132 to the measurement point 101;
Φ, is the phase of the measurement point 101 by lighting of a first optical probe 681; Φ2 is the phase of the measurement point 101 by lighting of a second optical probe 682;
Φ3 is the phase of the measurement point 101 by lighting of a third
optical probe 683;
Δ^j is an initial phase difference between two point light sources 111 and 112 constituting the first optical probe 681;
Aφ2 is an initial phase difference between two point light sources 121 and 122 constituting the second optical probe 682;
Aφ3 is an initial phase difference between two point light sources 131
and 132 constituting the third optical probe 683; (xι,yι,zι) is spatial coordinates of the first point light source 111 ;
(x2.Y2. 2) is spatial coordinates of the second point light source 112; (x3.y3.z3) is spatial coordinates of the third point light source 121 ; (x4.y4.z4) is spatial coordinates of the fourth point light source 122; (x5.y5.z5) is spatial coordinates of the fifth point light source 131; (xδ.Yβ.Zδ) is spatial coordinates of the sixth point light source 132;
(x,y,z) is spatial coordinates of the measurement point 101 of a measurement object 100; and
φx, φ2, φ3, φ4, φ5, and φ6 are the initial phases of the first to sixth point
light sources.
The measurement algorithm is to obtain spatial coordinates (x,y,z) of any one point 101 of the measurement object 100 using the above parameters.
Spatial coordinate values of six point light sources constituting three optical probes are xi, yi, zι,x2, Y2, z2, 3, Y3, z3, x, y4, z4, xs, Ys, z„, Xδ, Yβ, and ZQ. Hereinafter, these 18 parameters will be referred to as ' system parameters' . The system parameters are determined through a series of calibrations. The calibrations are beyond the scope of the present invention and thus a detailed description thereof is omitted.
FIG.3 illustrates a spatial distance from any one point (x.y.z) on a measurement object to each point light source. The difference between spatial distances is expressed by:
?3
- ( _ 4)2 +(y-y ~ +(z~z)2 •(2)
r5~r6=^(x-x5)2+(y-y5)2+(z~z5)2 ~^(x-x6)2+(y-y6)2+(z-z6)2
(3) To determine the measurement point (x.y.z) from the above Equations
(1) to (3), an optical path phase difference corresponding to the spatial distance difference should be obtained.
In order to obtain the optical path phase difference, a process of analyzing Equation (1) represented by an expression for a first optical probe is first explained.
Assuming that two point light sources of the first optical probe are spherical waves ui and u2, as given by the following Equations (4) and (5), the optical path phase difference between the measurement point and the two point light sources can be measured by analyzing an interference pattern generated when the spherical wave traveling toward the measurement object from the two point light sources is incident upon the measurement point. The interference pattern obtained from the measurement point is expressed by the following Equation (6).
Ui = A e-Ai<rM) ( )
1
„, = 2.e- <*^) (5)
/ = (M, + u2)(u{ + u2) * ■(6)
A2 A A
(^ .χιr) + (^-) + 2^cos[k(rl -r2) + φl -φ2]
F ' B)++( -) + 2^^(os[k( l - r2) + Aφ ] rr 1 r ', )+2^ 2 r ?,f : r2
( ) + (4) ) ++ 22- coβtΦ
The phase x is calculated through a known phase shifting algorithm. The phase Φ, is a sum of the spatial distance difference k(r - r2) and the difference Aφx between initial phases at ends of two optical fibers. From the above equations, the following Equations (7) to (9) are obtained.
^(x-x,)2 +(y-y1)2 +(z-z,)2 -^(χ-χ2)2 + (y-y2)2+(z-z2f =Φ, -Aφx
(7)
( -x, +(y~y,)2 +(z-z3)2 -^(x-Xi) +(y-y4)2+(z-z4)2 =Φ2 - Aφ2
(8)
The spatial coordinates (x.y.z) of the measurement point 101 can be determined by the numerical analysis of Equations (7) to (9) of nonlinear simultaneous equations. The spatial coordinates of the measurement point are obtained from the following processes of:
1) determining coordinate values and initial phase differences of point light sources constituting optical probes (since the coordinate values and initial phase differences of the point light sources can be determined by various methods, a detailed description thereof is omitted herein);
2) generating an interference pattern by irradiating light to a measurement object having any shape from a first optical probe;
3) calculating a distance between the first optical probe and the measurement point by using a known phase shifting algorithm; 4) generating an interference pattern by irradiating light to the measurement object having any shape from a second optical probe;
5) calculating a distance between the second optical probe and the measurement point by using the known phase shifting algorithm;
6) generating an interference pattern by irradiating light to the measurement object having any shape from a third optical probe; 7) calculating a distance between the third optical probe and the measurement point by using the known phase shifting algorithm;
8) constructing Equations (7)to(9) using the above results;
9) determining the spatial coordinates (x.y.z) of the measurement point by applying a known numerical analysis algorithm; 10) determining the spatial coordinates of all points desired to be measured for a measurement object having any shape through the above processes; and
11) restoring a profile of the measurement object by applying a known three-dimensional restoring graphic algorithm. The results restored through the above processes are displayed in various forms according to user purposes.
A description will be made of a measurement algorithm using six optical probes which are not influenced by the initial phase difference between two point light sources constituting each optical probe. Parameters in equations to be expressed later are as follows: ri is a spatial distance from a first point light source 211 to any one
measurement point 201 (r = J(x-xl)2 +(y-yx)2 +(z-zλ)2 ),'
r2 is a spatial distance from a second point light source 212 to the
measurement point 201 (r2 = j(x-x2)2 + (y-y2)2 +(z-z 2 );
r3 is a spatial distance from, a third point light source 221 to the
measurement point 201 (r3 =
r4 is a spatial distance from a fourth point light source 222 to the
measurement point 201 (r4 -^(x-x4)2 +(y-y4)2 +(z-z4)2 ),'
rs is a spatial distance from a fifth point light source 231 to the
measurement point 201 (r5 = ^j(x-x5)2 +(y-y5)2 +(z~ s)2 )',
r& is a spatial distance from a sixth point light source 232 to the
measurement point 201 (r6 =^(x-x6)2 +(y-y6)2 +(z-z6)2 )',
r7 is a spatial distance from a seventh point light source 241 to the
measurement point 201 (r7 = ^j(x-x7)2 +(y-y7)2 +(z-z7)2 ),'
rs is a spatial distance from an eighth point light source 242 to the
measurement point 201 (r8 = ΛJ(X-XS)2 +(y-y%)2 +(z-zs)2 )',
rg is a spatial distance from a ninth point light source 251 to the
measurement point 201 (r9 = sj(x-x9)2 +(y-y9)2 +(z-z9)2 )',
rio is a spatial distance from a tenth point light source 252 to the
measurement point 201 (r10 =^(x-x10)2 +(y~yιo)2 +(z-zιo)2 );
-rπ is a spatial distance from an eleventh point light source 261 to the
measurement point 201
ri2 is a spatial distance from a twelfth point light source 262 to the
measurement point 201 (}2=^j(x-xn)2 +(y-y12)2 +(z-zl2)2 )',
roi is a spatial distance from the first point light source 211 to any one
object point 202 (r01 = j(χQ-xl)2 + (y0-yl)2 +(z0-zl)2 );
ro2 is a spatial distance from the second point light source 212 to the
object point 202 (r02 = ^(x0 -x2)2 +(yQ -y2)2 + (z0 -z2)2 );
ro3 is a spatial distance from the third point light source 221 to the
object point 202 (r03 =
ro4 is a spatial distance from the fourth point light source 222 to the
object point 202 (r04 =
i"05 is a spatial distance from the fifth point light source 231 to the
object point 202 (r0S= j(x0 -x5)2 +(y0 -y5)2 +(z0-z5)2 );
roe is a spatial distance from the sixth point light source 232 to the
object point 202 ( 06 = ^](x0 -x6)2+ (y0 ~y6)2+ (z0 -z6)2);
ro7 is a spatial distance from the seventh point light source 241 to the
object point 202
roe is a spatial distance from the eighth point light source 242 to the
object point 202
rog is a spatial distance from the ninth point light source 251 to the
object point 202 (r09 = ^](χ0 -χ9)2 +(y0 -y9)2 +(z0-zg)2 );
roio is a spatial distance from the tenth point light source 252 to the
object point 202 (row=^(x0 -χ10)2+(y0 -yi0)2 +(z0 -zl0)2 );
ron is a spatial distance from the eleventh point light source 261 to
the object point 202 (ron =^j(x0 -xn)2 +(y0 -yn)2 +(z0-zn)2 );
roi2 is a spatial distance from the twelfth point light source 262 to the
object point 202 (r012 = ^(x0-xa)2 +(yQ -y12)2+(z0 -zl2)2 );
Φ1,Φ2,Φ3,Φ4,Φ5, and Φ6 are phases of the measurement point 201 by
lighting of first to sixth optical probes 210, 220, 230, 240, 250, and 260; and
Φo1-Φo2,Φo3.φo4.φo5.φo6'Φo7.φo8.Φo9-Φoιo.φoπ-φo12 are the phases of
the measurement point 202 by lighting of first to twelfth point light sources 211, 212, ,221, 222, 231, 232, 241, 242, 251, 252, 261, and 262.
In order to determine the spatial coordinates (x,y,z) of the measurement point from Equations (7) to (9), the initial phase difference Aφ between two point light sources generated from each optical probe should be determined. The initial phase difference Aφ can be removed by subtracting the phase value at any object point from the phase values of all measurement points. That is, since any object point has three coordinate values, three optical probes are additionally provided to expand the simultaneous equations. A description will be made of a method for determining coordinates
(x,y,z) of any measurement point 201 on the measurement object 200 using six optical probes with reference to FIG.4.12 point light sources 211, 212,
221, 222, 231, 232, 241, 242, 251, 252, 261, and 262 constitute six optical probes each consisting of two point light sources. Equation (7) is constructed by analyzing an interference pattern at the measurement point 201 irradiated from the first optical probe 210. Similarly, an interference pattern at any measurement point 202 can be represented by an equation. The interference pattern generated when
two spherical waves u0l and u02 traveling toward the object from the fist and
second point light sources 211 and 212 of the first optical probe are incident upon the measurement point 202 is represented by:
I = (uol +u02)(uol +u02) * (10)
_ = A (^r-) + ( ,^A - ■) + 2^ ΛlΛ^) cos[k(r0l -r02) + Aφm]
01 '02 '01'02
Equation (10) can be expressed in the form of Equation (7). The initial phase differences of Equations (7) to (9) can be removed by using Equations (7) and (10), and the defined parameters. This is possible by subtracting the phase value of the object point 202 from the phase values of all measurement points. Equation (11) shows a result eliminating the initial phase value in the first optical probe 210 through the above processes. The same processes are applied to the second to sixth optical probes 220, 230, 240, 250, and 260, resulting in the following Equations (12)-(16).
>-3-'4->"03+>"04 =Φ2- 02 ( 2)
r5 -r6- r05+ r06 =φ 3-φ03 (13)
'7-?8-'*07+'"08= 4-φ04 d4)
ru ~rl2 -ron +r0l2=Φ6 -Φ06 (16)
The above Equations (11) to (16) show the phase values without the initial phase values of the point light sources.
The spatial coordinates of each measurement point can be calculated by analyzing the above nonlinear simultaneous equations obtained from the six or more optical probes. This is achieved through a known numerical analysis and thus a detailed description thereof is omitted.
A measuring system to which the above-described measurement algorithm is applicable will be described hereinbelow. FIG.5 is a schematic diagram of a measuring system according to the present invention.
The measuring system is comprised of a central processing unit 560, a light source unit 500, and a detecting unit 530. The central processing unit
560 includes a central processor 563 which is in charge of the entire system, an operator 564 for performing operations for measurement results, an image processor 565 for displaying the measurement results, an optical
switch controller 562 for controlling an optical switch 502, and a phase shifting controller 561 for controlling phase shifters 506, 507 and 508. The light source unit 500 includes a light source 501, the optical switch 502, optical distributors 503, 504 and 505, the phase shifters 506, 507 and 508, and optical probes 509, 510 and 511. The detecting unit 530 includes a detector 532 and a detector controller 531.
The light source unit is shown in detail in FIG. 6.
Light generated from a light source 611 is incident upon a single- mode optical fiber 613 through a lens 612. The incident light is selectively transmitted to optical fibers 631, 632 and 633 by an optical switch 614. The optical fiber to be transmitted is controlled by an operation/controller 600. The light transmitted to the optical fiber 631 is split into two lights. The two lights pass through optical fibers 671 and 672, respectively, and are assembled in an optical probe 681. One of the two optical fibers 671 and 672 is wound around a piezoelectric element (PZT) 661 dozens of times so as to change an optical path. If a voltage is applied to the PZT 661 by the operation/controller 600, the PZT 661 is expanded in a radius direction and the optical fiber wound around the PZT 661 is also expanded, thereby changing the optical path. The PZT for changing the optical path is used to apply a known phase shifting algorithm.
FIG. 7 is a sectional view of an optical probe comprised of two point light sources.
Two optical fibers 720 and 721 are assembled in an optical probe. The covered materials of ends 710 and 720 of the optical fibers 720 and 721 are removed so as to expose a cladding of each of the optical fibers 720 and 721. Thereafter, the two optical fibers 720 and 721 adhere closely to each other and are inserted into an optical fiber chuck 700. Tips 740 and 741 of the two optical fibers 720 and 721 are cut to be aligned with each other and a sealing 730 is put on the front of the optical fiber chuck 700.
A frame for fixing the optical probe is illustrated in FIG. 8. Six optical probe fixers 811-816 fix three or more optical probes. Respective optical probes are inserted into the fixers. Each fixer is constructed such that an optical axis of the optical probe can be varied at a constant angle. FIG. 8A illustrates positions of a detecting unit 850 and a measurement object 870 on the basis of a frame 860. On the basis of the frame 860, the detecting unit 850 is fixed at the opposite side of the measurement object 870, and a hole 863 is positioned at the center of the frame 860 to observe the measurement object 870. A connector 862 is provided to assemble the frame 860 with a base part such as a vibration isolation table.
A description will be made of a process for generating an interference pattern from two point light sources of an optical probe, and obtaining an optical path difference between the two point light sources and a measurement point by analyzing the interference pattern reflected on an object.
Referring to FIG. 6, light generated from the light source 611 is incident upon the single-mode optical fiber 613. The incident light is selectively incident upon one of the optical fibers 631 to 634 via the optical switch 614. The light selectively incident upon the optical fiber 631 is split by an optical fiber coupler 651 and transmitted to the end of the optical fiber inserted into the optical probe 681, thereby emitting a spherical wave into the air. The optical fiber wound around the PZT 661 is increased in the entire length as the PZT 661 is expanded in a radius direction. Therefore, the point light sources generated from the ends of the two optical fibers 671 and 672 create spherical waves with different phases. PZTs 661 to 663 are sequentially operated by a PZT signal distributor 620 according to a signal of the operation/controller 600. The created spherical waves mutually interfere with each other to form an interference pattern, and the interference pattern is captured by an image acquiring unit 670. The image acquiring unit 670 uses a CCD (Charge-Coupled Device) camera, such as a two-dimensional line camera or a three-dimensional area camera, which is capable of converting the optical intensity of the acquired image into a digital value on a pixel basis. The image acquiring unit 670 acquires the interference patterns generated from the three optical probes 681 to 683 in time order by the operation/controller 600 controlling the optical switch 614 and the PZT signal distributor 620. The optical path difference between the measurement object and two point light sources constituting one optical probe is calculated by analyzing the interference pattern generated from the
optical probe and the coordinate value of the measurement point is determined by using the measurement algorithm. The analysis of the interference pattern uses the phase shifting algorithm. The three optical probes 681 to 683 are fixed by a mechanical frame 690 for maintaining the optical probes at a constant distance. Since the measurable size of the object is determined according to an angle at which the optical probe is fixed at the frame and to the distance between the optical probes, a device for controlling the angle is installed to enable the measuring system to measure the various-sized object. To apply the known phase shifting algorithm, a few interference patterns with different initial phases are required. This is achieved by changing the optical path of one optical fiber by controlling the voltage applied to the PZTs 661-663 under the control of the operation/controller 600. As the operation/controller 600, a general computer, an industrial computer, a central control unit etc. may be used. The processes of changing the optical path using the PZT, acquiring the interference pattern, and calculating the optical path difference between two point light sources and measurement point are known to those skilled in the art, and thus no further description will be given. While the present invention has been described with reference to the particular illustrative embodiments, it is not to be restricted by the embodiments but only by the appended claimed. It is to be appreciated that
those skilled in the art can change or modify the embodiments without departing from the scope and spirit of the present invention.
Claims
1. A profile measuring system using a point diffraction light source based on multilateration in measuring a surface profile of an object having any shape by using a measurement algorithm, comprising: a light source unit 500 including a plurality of optical probes each having two point light sources installed therein, a light source 501 for supplying light to the point light sources, an optical distributor for distributing light to the optical probes, and a phase shifter for shifting a phase of one of the two point light sources; a detecting unit 530 including a detector for acquiring an interference pattern generated on a measurement target object by irradiating the point light sources to the measurement target object, and a detector controller; and a central processing unit 560 including a central processor 563, an operator 564, an image processor 565, an optical switch controller 562, and a phase shifting controller 561.
2. A profile measuring method using a point diffraction light source based on multilateration in measuring a surface profile of an object having any shape by using three optical probes each having two point light sources installed therein in a measuring system including a central processing unit 560, an optical source unit 500 and a detecting unit 530, the method comprising a measurement algorithm including the steps of: determining spatial coordinates of any one measurement point through a known numerical analysis of simultaneous equations represented by following Equations (a), (b), and (c); and determining spatial coordinates for all surfaces of the object;
l(x-x3)1+(y-y3)1+(z~z3)2-^(x-x4)2+(y-y4)2+(z-z4)2=Φ2-Aφ2
(b)
^(x-x5)2+(y-y5)2+(z-z5)2-,](x-x6)2+(y-y6)2+(z-z6)2 =Φ3-Aφ3
(c) where Φ[ is the phase of the measurement point by lighting of a first optical probe;
Φ2 is the phase of the measurement point by lighting of a second optical probe;
Φ3 is the phase of the measurement point by lighting of a third optical
probe;
Aφλ is an initial phase difference between first and second point light sources constituting first optical probe;
Aφ2 is an initial phase difference between third and fourth point light sources constituting the second optical probe;
Aφ3 is an initial phase difference between fifth and sixth point light
sources constituting the third optical probe; (xι,yι,zι) is spatial coordinates of the first point light source; (x2.Y2.z2) is spatial coordinates of the second point light source; (x3.y3.z3) is spatial coordinates of the third point light source; (x4.y4.z4) is spatial coordinates of the fourth point light source; (x5.Y5.z5) is spatial coordinates of the fifth point light source;
( δ.Yδ.Zδ) is spatial coordinates of the sixth point light source; and (x.y.z) is spatial coordinates of the measurement point of the object.
3. A profile measuring method using a point diffraction light source based on multilateration in measuring a surface profile of an object having any shape by using six optical probes each having two point light sources installed therein in a measuring system including a central processing unit, an optical source unit and a detecting unit, the method comprising a measurement algorithm including the steps of: determining spatial coordinates (x,y,z) of one measurement point through a known numerical analysis of simultaneous equations represented by the following Equations (d), (e), (f),(g),(h), and (i); and determining spatial coordinates for all surfaces of the object;
'ϊ - ?2 - 'Oι + >-o2 = Φι - oι (d)
>"3 - >"4 - >"03 + 704 = Φ2 - Φ02 (β)
7-5 - 7-6 - 7-05 + 7"06 = Φ3 - 03 (f)
7-7 - 7-8 - 7-07 + 7-08 = Φ4 - Φ04 .(g) ?9 - 7}0 - 7θ9 + 7-010 = Φ5 - φ05 &)
7i l - T-,2 - 7OI I + -012 = 6 ~ Φ06 (
where ri is a spatial distance from a first point light source to the measurement point; r2 is a spatial distance from a second point light source to the measurement point; r3 is a spatial distance from a third point light source to the measurement point; r4 is a spatial distance from a fourth point light source to the measurement point; rs is a spatial distance from a fifth point light source to the measurement point; re is a spatial distance from a sixth point light source to the measurement point; r7 is a spatial distance from a seventh point light source to the measurement point; rs is a spatial distance from an eighth point light source to the measurement point; rg is a spatial distance from a ninth point light source to the measurement point; rio is a spatial distance from a tenth point light source to the measurement point; rn is a spatial distance from an eleventh point light source to the measurement point; ri2 is a spatial distance from a twelfth point light source to the measurement point; roi is a spatial distance from the first point light source to any object point; ro2 is a spatial distance from the second point light source to the object point; ro3 is a spatial distance from the third point light source to the object point; ro4 is a spatial distance from the fourth point light source to the object point; ros is a spatial distance from the fifth point light source to the object point; roe is a spatial distance from the sixth point light source to the object point; ro7 is a spatial distance from the seventh point light source to the object point; ros is a spatial distance from the eighth point light source to the object point; rog is a spatial distance from the ninth point light source to the object point; roio is a spatial distance from the tenth point light source to the object point; ron is a spatial distance from the eleventh point light source to the object point; and roi2 is a spatial distance from the twelfth point light source to the object point.
4. A profile measuring method using a point diffraction light source based on multilateration in measuring a surface profile of an object having any shape by using a plurality of optical probes each having two point light sources installed therein in a measuring system including a central processing unit 560, an optical source unit 500 and a detecting unit 530, the method comprising the steps of:
(i) determining coordinate values and initial phase differences of point light sources installed in optical probes;
(ii) generating an interference pattern by irradiating light to a measurement target object having any shape from a first optical probe;
(iii) calculating a distance from the first optical probe to a measurement point by using a known phase shifting algorithm; (iv) performing the steps (ii) and (iii) for all optical probes;
(v) determining spatial coordinates of the measurement point through operations for the calculated distances! and (vi) determining spatial coordinates of all measurement points by repeatedly performing the steps (ii), (iii), (iv), and (v) for all measurement points.
5. The profile measuring system as claimed in claim 1, wherein the surface profile is measured by the processes of determining coordinate values and initial phase differences of the point light sources installed in the optical probes, generating an interference pattern by irradiating light to the measurement target object having any shape from a first optical probe, calculating a distance from the first optical probe to a measurement point by using a known phase shifting algorithm, generating interference patterns by sequentially irradiating light to the measurement target object from all optical probes, calculating distances from the respective optical probes to the measurement point by using the known phase shifting algorithm, and determining spatial coordinates of all measurement points through operations for the calculated distances by using the measurement algorithm.
6. The profile measuring system as claimed in claim 1 or 5, wherein the measurement algorithm uses one of the measurement algorithms proposed in claim 2 or 3.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR10-2002-0005062A KR100462071B1 (en) | 2002-01-29 | 2002-01-29 | The method and system to measure the large scale using point diffraction based on the multilateration |
| KR2002-0005062 | 2002-01-29 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2003064971A1 true WO2003064971A1 (en) | 2003-08-07 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/KR2002/001333 WO2003064971A1 (en) | 2002-01-29 | 2002-07-15 | Method and system for measuring profile of large-area using point diffraction light source based on multilateration |
Country Status (2)
| Country | Link |
|---|---|
| KR (1) | KR100462071B1 (en) |
| WO (1) | WO2003064971A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010023442A2 (en) * | 2008-08-26 | 2010-03-04 | The University Court Of The University Of Glasgow | Uses of electromagnetic interference patterns |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02228512A (en) * | 1989-03-01 | 1990-09-11 | Agency Of Ind Science & Technol | Highly accurate laser measurement method and apparatus for surface of solid |
| JPH04186105A (en) * | 1990-11-21 | 1992-07-02 | Kowa Co | Optical measuring method and device |
| US5341212A (en) * | 1991-07-19 | 1994-08-23 | Olympus Optical Company Limited | Wave front interferometer |
| US5398113A (en) * | 1993-02-08 | 1995-03-14 | Zygo Corporation | Method and apparatus for surface topography measurement by spatial-frequency analysis of interferograms |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| ATE188060T1 (en) * | 1996-02-29 | 2000-01-15 | Siemens Ag | AIRPORT CONTROL SYSTEM, IN PARTICULAR AIRPORT GROUND TRAFFIC CONTROL SYSTEM |
| WO1997036144A1 (en) * | 1996-03-22 | 1997-10-02 | Loughborough University Innovations Limited | Method and apparatus for measuring shape of objects |
| DE19721882C2 (en) * | 1997-05-26 | 1999-04-29 | Bosch Gmbh Robert | Interferometric measuring device |
-
2002
- 2002-01-29 KR KR10-2002-0005062A patent/KR100462071B1/en not_active IP Right Cessation
- 2002-07-15 WO PCT/KR2002/001333 patent/WO2003064971A1/en not_active Application Discontinuation
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02228512A (en) * | 1989-03-01 | 1990-09-11 | Agency Of Ind Science & Technol | Highly accurate laser measurement method and apparatus for surface of solid |
| JPH04186105A (en) * | 1990-11-21 | 1992-07-02 | Kowa Co | Optical measuring method and device |
| US5341212A (en) * | 1991-07-19 | 1994-08-23 | Olympus Optical Company Limited | Wave front interferometer |
| US5398113A (en) * | 1993-02-08 | 1995-03-14 | Zygo Corporation | Method and apparatus for surface topography measurement by spatial-frequency analysis of interferograms |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010023442A2 (en) * | 2008-08-26 | 2010-03-04 | The University Court Of The University Of Glasgow | Uses of electromagnetic interference patterns |
| WO2010023442A3 (en) * | 2008-08-26 | 2010-08-26 | The University Court Of The University Of Glasgow | Uses of electromagnetic interference patterns |
| US9618369B2 (en) | 2008-08-26 | 2017-04-11 | The University Court Of The University Of Glasgow | Uses of electromagnetic interference patterns |
Also Published As
| Publication number | Publication date |
|---|---|
| KR100462071B1 (en) | 2004-12-16 |
| KR20030064966A (en) | 2003-08-06 |
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