JPH0481125B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a three-dimensional measurement method for non-contact measurement of the position of each point on the surface of a three-dimensional object such as a human body or an object.

[Conventional technology]

Conventionally, methods for measuring the three-dimensional shape of a human body, object, etc. include a contact method, in which a sensing probe is brought into contact with the object to be measured, and a non-contact method, such as stereo photography, moiré topography, and optical sectioning. These methods are used for industrial robots,
It is widely applied as an object recognition technology for various inspection devices.

In the case of the contact method, only objects to be measured that can be touched can be measured, which limits the number of objects that can be measured.Also, since the position of each point on the surface of the object is measured by contact, it takes an extremely long time to measure. It takes.

Therefore, it is desirable to measure the shape of the object to be measured without contacting the object, as in the non-contact method described above.

[Problem that the invention seeks to solve]

By the way, in the case of the conventional non-contact method, the position of each point on the three-dimensional surface to be measured is calculated based on shape recognition of the object to be measured, so the position of each point on the three-dimensional surface is measured. To do so, it is necessary to determine the target measurement point from the obtained shape information and calculate the two-dimensional or three-dimensional position of the determined measurement point. In this case, complex calculation processes such as function calculations are required. There is a problem that it is necessary to perform calculations and that calculations take time.

In addition, the measurement devices that implement both of the above methods have very low resolution, and if the object to be measured is small or the surface of the object to be measured is uneven, measurement errors may increase or measurements may not be possible. , there is a problem of lack of reliability.

[Means for solving problems]

In this invention, a solid body to be measured is placed on a horizontal support stand on a base, a plurality of pillars are erected around the base, and a vertical line longer than the solid body is attached to each of the pillars. a light projecting means for irradiating the three-dimensional object with slit light of a shape variably in the left-right direction; and a pair of imaging means for imaging the irradiated portion of the three-dimensional object from the left and right directions of the light projecting means. The non-contact measuring device is fixed, and the irradiation position of the light projecting means of each of the measuring devices is varied to move the light irradiating portion in the left and right direction within the overlapping field of view of both the imaging devices, and the non-contact measuring device is fixed. Based on the positional information of the slit light beams outputting each pair of images, the vertical direction and the left and right directions are defined as the Z-axis direction and the X-axis direction3.
The position of point G (x, y, z) of the irradiated part in dimensional coordinates is expressed as: x=(d-Kx)・{L/L+(d-e)-1}+dy -e) z=Kz・r d, e is the X of point G at each of the pair of imaging outputs
Axial distance data L is the distance between the pair of imaging means in the X-axis direction Kx, Ky are the coefficients in the X-axis and Y-axis directions that are set based on the lens magnification and position of the pair of imaging means r is The scanning line number Kz of point G in a pair of image pickup outputs is obtained from four arithmetic operations of coefficients determined by the number of scanning lines, width, and lens magnification, and each position on the surface of the three-dimensional object is calculated and measured. This is a three-dimensional measurement method.

[Effect]

Then, the light emitting means of each measuring instrument illuminates the circumferential surface of the solid with a sufficient length of slit light in the vertical direction so as to surround the solid, and the irradiation position of each slit light can be adjusted without moving each measuring device. Move left and right.

Furthermore, the irradiated portion of each slit light is imaged from the left and right directions of the light projecting means by a pair of imaging means of each measuring instrument, and the slit light in each pair of image outputs obtained by this imaging is By simple arithmetic operations based on the position information, the position of the irradiated portion of each slit light is calculated, and each position on the surface of the three-dimensional object is calculated and measured.

〔Example〕

Next, the present invention will be described in detail with reference to drawings showing one embodiment thereof.

First, in FIG. 1 showing the measuring device, 1 is a base, 2 is a horizontal support placed on the base 1, and 3 is a horizontal support stand placed on the base 1.
are the three-dimensional object to be measured placed on the support stand 2, 4a,
Reference numerals 4b, 4c, and 4d are four pillars erected at the four corners of the base 1, and the inner surfaces of the pillars 4a and 4c face each other via the solid body 3, and the pillars 4
The inner surfaces of b and 4d face each other with the solid body 3 in between.

5a, 5b, 5c, 5d are fixed members 6a, 6
Four non-contact measuring devices are attached and fixed to the upper ends of the respective pillars 4a to 4d via b, 6c and 6d, 7 is a light projecting means provided on each of the measuring devices 5a to 5d, 8α, 8β is the left side of the light projecting means 7;
A pair of imaging means are provided on the right side, each consisting of a two-dimensional sensor device such as a CCD area image sensor.

The light projecting means 7 and the imaging means 8α, 8β of each of the measuring instruments 5a to 5d are constructed as shown in FIG. A light source that outputs light; 10b is an expansion lens made of a convex tube lens that increases the length of the slit light from the light source 10a; 10c is a rotatable reflecting mirror; Light is irradiated onto the surface of the solid 3 so as to be movable in the left and right directions.

11αa and 11βa are light receiving elements, respectively.
An image sensor formed by arranging CCDs in a two-dimensional matrix of M rows vertically and N columns horizontally, 11αb,1
1βb is the reflected light from the surface of the solid body 3.
1αa and 11βa, one of the imaging means 8α is formed by the imaging sensor 11αa and the lens 11αb, and the imaging sensor 1
1βa, the other imaging means 8β by lens 11βb
is formed.

By the way, in order to explain the measurement position in the XYZ three-dimensional coordinate system, as shown in Fig. 2, the lens 11
The left and right direction in FIG. 1 connecting the center points of αb and 11βb is taken as the X-axis direction, and
The irradiation direction of the slit light is taken as the Y- and Z-axis directions, respectively, and the vertical direction in FIG. 1 parallel to the irradiated slit light.

The length of the slit light is set to be sufficiently longer than the height of the solid body 3, and both imaging means 8α, 8
For β, the imaging field of view is fixed so that the portion of the solid 3 irradiated with the slit light is imaged overlappingly.

Further, the rotation of the reflecting mirror 10c is controlled by a rotation control means (not shown), and by rotating the reflecting mirror 10c, the irradiation position of the slit light of the light projecting means 7 is within the overlapping field of view of both the imaging means 8α and 8β. It is variable in a direction perpendicular to the measurement direction, that is, in the X-axis direction, and at this time, the slit light irradiated portion of the solid 3 also moves in the X-axis direction.

That is, the slit light S shown in FIG. 2 changes sequentially in the X-axis direction within the overlapping fields of view of both imaging means 8α and 8β.

And the imaging sensor 11 of both imaging means 8α, 8β
By αa, 11βa, measuring instruments 5a to 5d of solid 3
Each slit light irradiation area is imaged,
At this time, the imaging surfaces of both image sensors 11αa and 11βa
For example, as shown in Fig. 3a and b, respectively, slit light images Sα and Sβ are formed in the vertical direction on Fα and Fβ, and only the portions of the slit light images Sα and Sβ are formed on both imaging planes Fα and Fβ. It becomes brighter.

Furthermore, each of the image sensors 11αa and 11βa
Both image sensors 1
Imaging outputs of one scanning line each of 1αa and 11βa are formed, and the imaging outputs of each scanning line are sequentially output from both imaging means 8α and 8β.

Note that the horizontal direction in Figures a and b corresponds to the X-axis direction, and the vertical direction corresponds to the Z-axis direction, and the horizontal lines A ₁ , ..., Am, Am ₊₁ , Am ₊₂ ,
Am ₊₃ ,..., An indicate the first to Nth scanning lines of the image sensor 11αa, and horizontal lines B ₁ ,..., Bm, Bm ₊₁ , Bm ₊₂ , Bm ₊₃ , ..., Bn
denotes the first to Nth scanning lines of the imaging sensor 11βa, and the imaging outputs of each scanning line of both sensors 11αa and 11βa are sequentially read out at the same timing.

A pair of analog imaging outputs read out from both imaging sensors 11αa and 11βa of each of the measuring instruments 5a to 5d are sent to an electronic computer 12 shown in FIG.
are respectively input to image processing means for each of the measuring instruments 5a to 5d provided in the.

Each of the image processing means is constructed as shown in FIG. Analog imaging outputs of each scanning line sequentially outputted from the imaging sensors 11αa and 11βa are captured at the timing of the clock signal, and are sliced at a predetermined slice level to create slit optical images Sα,
A digital image signal is formed in which only the Sβ portion is at a high level.

15α and 15β are a pair of address counters, and both image sensors 1 are
Both processing circuits 1 are processed by slit light images Sα and Sβ from the reference point position at the left end of each scanning line 1αa and 11βa.
Both image sensors 11αa and 11 up to the point where the digital image signals of 4α and 14β become high-level pulses
The distance of βa in a pair of imaging outputs is counted, and distance data in the X-axis direction of each point of the irradiated portion in each of the pair of imaging outputs is output.

16 is an arithmetic circuit, and both counters 15α, 1
The Z-axis direction of each point in the slit light irradiation area consists of a pair of distance data in the X-axis direction simultaneously input from 5β, the scanning line number obtained by counting the clock signal, and the preset scanning line width. The position of each point in the slit light irradiation area in the three-dimensional coordinate system is calculated from the four arithmetic operations described below based on the position information of the slit light such as data.

17 is a storage unit that stores the coordinate position of each point of the irradiation part calculated by the arithmetic circuit 16; 19 is a processing circuit 14α, 14β; counters 15α, 15β;
An image processing means consisting of an arithmetic circuit 16 and a storage section 17; 20 is a display condition setting section; 21 is a recognition circuit; based on the conditions set in the setting section 20, the coordinate position of each point stored in the storage section 17 is from solid 3
The coordinate position of each point stored in the storage section 17 and a display signal indicating the identified dimensions, surface condition, shape, etc. are output to the display means 22 in FIG. 4.

As shown in FIG. 2, linear slit light is emitted from the light projecting means 7, and the irradiated portion of the slit light is imaged from two directions by imaging means 8α and 8β on the left and right sides of the light projecting means 7. For example, slit light images Sα and Sβ shown in FIGS. 3a and 3b are formed on both imaging means 8α and 8β, respectively.

Further, the first scanning line A 1 to the Nth scanning line A ₁ to Nth
The imaging outputs of the scanning lines An are sequentially output, for example, as shown in FIG.
When the imaging outputs Am, Am ₊₁ , Am ₊₂ , and Am ₊₃ are sequentially output, at the same timing, the processing circuit 14β is output from the image sensor 11βa of the imaging means 8β.
Then, as shown in FIG. 7a, the imaging outputs of Mth to M+3 scanning lines Bm, Bm ₊₁ , Bm ₊₂ and Bm ₊₃ are sequentially output.

The processing circuits 14α and 14β sequentially slice the analog imaging outputs for each scanning line from the image sensors 11αa and 11βa at a slice level l, and at this time, the level l is the slit optical image Sα,
Since the level is set to extract only the Sβ portion, only the slit light image Sα and Sβ portions in each scanning line output are extracted, as shown in Figures 6b and 7b. The imaging outputs of the means 8α and 8β are digitally converted.

Then, the digital signals of both processing circuits 14α and 14β are input to both counters 15α and 15β, respectively, and the counters 15α and 15β receive the reference point d ₀ at the left end of each scanning line, as shown in FIGS. 6c and 7c. _Each reference point pulse is formed at the timing of
am, am ₊₁ , am ₊₂ , am ₊₃ and bm, bm ₊₁ ,
Distance to bm ₊₂ , bm ₊₃ respectively Dam, Dam ₊₁ ,
Dam ₊₂ , Dam ₊₃ and Dbm, Dbm ₊₁ ,
Count Dbm ₊₂ and Dbm ₊₃ , and slit light image Sα
Distance data in the X-axis direction and slit light image Sβ
The distance data in the X-axis direction is output to the arithmetic circuit 16.

Next, the calculation of the calculation circuit 16 will be explained.

Now, to simplify the explanation, both imaging means 8
It is set so that the imaging fields of α and 8β are completely equal, and the left end of the imaging field of view coincides with the Z axis.
As shown in the figure, light at a point G (x, y, z) of the irradiated part of the slit light S at a certain point in time is transmitted to both imaging means 8.
Center point P of lenses 11αb and 11βb of α and 8β
(a, o, z) and Q (b, o, z), respectively, the image forming point and the center point P(a,
o, z) and Q (b, o, z) each passes through an arbitrary point c on the solid (object to be measured) side of the Y axis.
Points U (d, c, z), V (e,
c, z), the point G(x, y,
z) is a line segment passing through points P (a, o, z), U (d, c, z), and points Q (b, o, z), V (e, c, z)
It is found as the intersection with the line segment passing through.

And the points P (a, o, z), Q (b, o, z), U
(d, c, z), based on the values of V (e, c, z),
The X and Y axis components x and y of point G (x, y, z) can be found from the following equations (1) and (2).

x=a・e−b・d/a−b−d+e=b・d−a・e
/b-a+d-e = (d-a) {b-a/b-a+d-e-1}+d...(1) Formula y=c・(a-b)/a-b-d+e=c・(b-
a)/b-a+d-e...(3) By the way, b-a in equations (1) and (2) is for both image sensors 1
1αa and 11βa are the distances L, and d and e are the magnifications of the lenses 11αb and 11βb and the imaging means 8α and 8
This is the position of point G (x, y, z) in the X-axis direction on the imaging planes Fα, Fβ determined by the mounting position of β.

Then, d and e are obtained as distance data from the reference point d ₀ at the left end of each of the imaging planes Fα and Fβ.

Furthermore, a, b, and c are constants set by the mounting positions of the imaging means 8α and 8β, the magnifications of the lenses 11αb and 11βb, and the like.

Therefore, by setting constants a and c in the X and Y axis directions, which are set based on the magnification of the lenses 11αb and 11βb and the positions of the imaging means 8α and 8β, as Kx and Ky, the point G (x, y, z )'s X and Y axis components x,
y can be found by calculating the following equations (3) and (4).

x=(d-Kx)・{L/L+(d-e)-1}+d...Formula (3) y=Ky・L/L+(d-e)...Formula (4) On the other hand, point G( The Z-axis component z of the point G (x, y, z) is based on the scanning line number r of the point G (x, y, z) and the coefficient Kz determined by the number and width of the scanning lines and the magnification of the lenses 11αb and 11βb. It can be found by calculating the following equation (5).

z=Kz・r...Equation (5) Then, Kx, Ky, L in Equations (3) and (4) and Kz in Equation (5) are constants, and d and e are the counters 15α,
Since r is obtained as a pair of distance data in the X-axis direction input from 15β, and r is obtained by counting the clock signal, the arithmetic circuit 16 calculates (3) to (5) based on the position information of the slit light consisting of the set position information and the detected position information formed by a pair of distance data input from the counters 15α and 15β and the count data of the clock signal. Point G (x, y, z) by performing the four arithmetic operations of the formula
By calculating the position of and applying the calculation to each point of the slit light irradiation part, the three-dimensional position of each point of the slit light irradiation part in the XYZ coordinate system of FIG. 2 is calculated.

Note that when the fields of view of both imaging means 8α and 8β do not completely overlap, and when the vertical and horizontal directions of the imaging planes Fα and Fβ are misaligned with the Z and X axes, the amount of misalignment is added to the value of each formula. The three-dimensional position of each point in the slit light irradiation area is calculated by multiplying by a correction coefficient corresponding to .

Then, when the reflecting mirror 10c provided in the light projection means 7 of each of the measuring instruments 5a to 5d rotates by the same amount at the same timing and the slit light irradiation position of the measuring instruments 5a to 5d changes, each of the measuring instruments 5a to 5d The slit light irradiation part is the measuring device 5a to 5d.
It moves in the X-axis direction within the overlapping fields of view of both imaging means 8α and 8β, and at this time, the three-dimensional position of each point of each slit light irradiation portion of each of the measuring instruments 5a to 5d is calculated based on the four arithmetic operations described above. As a result, the position of each point on the surface of the solid body 3 is calculated and measured.

By the way, since the origin of the XYZ coordinate system in FIG. 2 is a different point for each measuring device 5a to 5d, the value of the position of each point calculated by the above calculation is
The value is from a different reference point every ~5d.

Therefore, it is necessary to convert the value of the position of each point calculated for each measuring device 5a to 5d into a value in a constant standard three-dimensional coordinate system regardless of the measuring device 5a to 5d.

In order to convert the value of the position of each point into a value in the standard three-dimensional coordinate system, measurement standard gauges are actually set up at the positions imaged by each measuring device 5a to 5d on the support stand 2. However, the measurement is performed using the gauge as follows.

That is, before measurement, the position of the origin of the three-dimensional coordinate source of each measuring device 5a to 5d is measured from the position of the scale of the imaged measurement reference gauge, etc., and the three-dimensional coordinate system of each measuring device 5a to 5d is determined. X-, Y-, and Z-axis components are respectively calculated for coordinate transformation to transform the position of the origin of , to the position of a reference three-dimensional coordinate system set in advance inside the solid 3, for example.

Then, the values of the X, Y, and Z axis components of the position of each point calculated in the three-dimensional coordinate system of each of the measuring instruments 5a to 5d are added or multiplied by each axis component for the coordinate transformation described above, and the Converts a position value to a value in the standard three-dimensional coordinate system.

As described above, the three-dimensional position of each point on the surface of the solid 3 is calculated and measured.

Based on the measured coordinate positions of each point on the surface of the solid 3, the recognition circuit 21 identifies the dimensions, surface condition, shape, etc. of the solid 3, and
Based on the setting conditions of the setting unit 20, the coordinate position of each measured point and the dimensions of the identified solid 3,
The surface condition, shape, etc. are displayed on the display means 22.

Therefore, according to the embodiment, the measuring device 5a
The slit light irradiation portion every ~5d is measured by measuring instruments 5a~5.
While moving in the left-right direction within the overlapping fields of view of both the imaging means 8α and 8β of each of the measuring instruments 5a to 5d, each slit light irradiated portion is imaged from two directions by the imaging means 8α and 8β of each of the measuring instruments 5a to 5d.

Furthermore, the computer 12 to which a pair of imaging outputs from each of the measuring instruments 5a to 5d is input, performs four simple arithmetic operations based on the positional information of the slit light in each pair of imaging outputs for each slit light irradiation area. The position of each point on the irradiated portion of each slit light, that is, the position of each point on the solid 3, is calculated and measured.

Then, the measurement position can be changed by moving the irradiation position of each slit light in the left and right direction without moving each measuring device 5a to 5d, and each point on the surface of the solid 3 can be calculated by a simple four-measure calculation. Since the measurement is carried out using the same method, the measurement position can be quickly changed without any mechanical movement, and calculations can be made in a shorter time than with conventional non-contact methods.
Each position on the surface of is measured.

In addition, in order to obtain a pair of imaging outputs by imaging the irradiated portion of each slit light from two directions, left and right, by each pair of imaging means 8α and 8β, for example, each of the measuring instruments 5a to 5d is Compared to a method in which one image pickup output is obtained for the irradiated portion of each slit light by using a light projection means 7 and one television camera, etc., the irradiation optical axis of the light projection means 7 and both imaging means 8
Reduce the angles formed with each of α and 8β, and
Accurate measurement can be carried out even when the surface of the solid 3 is small or when the surface of the solid 3 is uneven.

Furthermore, since the measurement is performed without contact, even if the solid 3 is made of rubber or other flexible and deformable material, it can be easily measured.

Furthermore, since linear slit light is used, the energy density is low and weak light is sufficient, and the three-dimensional object 3 will not be distorted by the heat of the illumination when the illumination is used.

In addition, both imaging means 8α of each measuring device 5a to 5d,
8β may be constituted by a MOS image sensor, an image pickup tube, or the like.

Further, the irradiation position of the slit light irradiated from the light projecting means 7 can also be varied by, for example, magnetic action without rotating the reflecting mirror 10c.

Furthermore, it goes without saying that the number of columns and measuring devices provided around the base 1 may be two or more.

[Effects of the Invention] As described above, according to the three-dimensional measurement method of the present invention, a plurality of three-dimensional measurement objects are attached to the supports 4a to 4d so as to surround the three-dimensional object to be measured 3 placed on the support stand 2 on the base 1. Non-contact measuring instruments 5a to 5d are provided, and each measuring instrument 5
A long vertical linear slit light is irradiated from the light projecting means 7 of a to 5d to the solid body 3 according to its height so as to be movable in the left and right direction, and the irradiated portion of each slit light is directed to one of the measuring instruments 5a to 5d. Images are taken by a pair of imaging means 8α and 8β, and based on the position information of the slit light in each pair of imaging outputs obtained by this imaging,
The position of the point G (x, y, z) of the irradiated part in three-dimensional coordinates with the vertical and horizontal directions as the Z-axis direction and the X-axis direction is x = (d - Kx) -e)-1}+d y=Ky・L/L+(d-e) z=Kz・r d and e are the X of point G at each of the pair of imaging outputs
Axial distance data L is the distance between the pair of imaging means in the X-axis direction Kx, Ky are the coefficients in the X-axis direction and Y-axis direction that are set based on the lens magnification, position, etc. of the pair of imaging means r is The scanning line number Kz of point G in a pair of image pickup outputs can be obtained from simple arithmetic operations using coefficients determined by the number of scanning lines, width, and lens magnification, and can be accurately measured in a non-contact manner.

[Brief explanation of the drawing]

The drawings show one embodiment of the three-dimensional measurement method of the present invention, in which FIG. 1 is a perspective view of a measuring device, FIG. 2 is an exploded perspective view of the non-contact measuring device shown in FIG. 1, and FIGS. 2 is a front view of the imaging screen of both image sensors, FIG. 4 is a circuit block diagram, FIG. 5 is a block diagram of the image processing means in the computer of FIG. 4, and FIGS. 6 a to c,
7a to 7c are timing charts for explaining the operation of FIG. 5, and FIG. 8 is a schematic diagram for explaining the operation of the arithmetic circuit of FIG. 3...Stereoscopic, 5a-5d...Non-contact measuring device, 7
...Light projecting means, 8α, 8β...imaging means.

Claims (1)

[Scope of Claims] 1. A three-dimensional object to be measured is placed on a horizontal support stand on a base, a plurality of pillars are erected around the base, and each pillar has a vertical support that is longer than the three-dimensional object. A light projecting means for irradiating the three-dimensional object with linear slit light in a variable direction in the left and right directions; and a pair of imaging devices for imaging the irradiated portion of the three-dimensional object from the left and right directions of the light projecting means. A non-contact measuring device having means is fixed, and the irradiation position of the light projecting means of each of the measuring devices is varied to move the irradiated portion in the left and right direction within the overlapping field of view of both the imaging means, and Based on the positional information of the slit light in the pair of imaging outputs of each measuring device, the vertical direction and the horizontal direction are determined to be the Z-axis direction and the X-axis direction3.
Point G (x, y, z) of the irradiated part in dimensional coordinates
The position of, X of point G at each output
Axial distance data L is the distance between the pair of imaging means in the X-axis direction Kx, Ky are the coefficients in the X-axis direction and Y-axis direction that are set based on the lens magnification, position, etc. of the pair of imaging means r is The scanning line number Kz of point G in a pair of image pickup outputs is obtained from four arithmetic operations of coefficients determined by the number of scanning lines, width, and lens magnification, and the position of each point on the surface of the three-dimensional object is calculated and measured. A three-dimensional measurement method characterized by: