JPS6114514A - Three diementional coordinate measuring instrument - Google Patents

Abstract

PURPOSE:To measure the three dimentional coordinates value of a target point with quick and most suitable measuring accuracy and with simple operation by irradiating a laser beam on the surface for object and by picking up the irradiating beam point thereof with an image camera. CONSTITUTION:A laser beam is irradiated by eye sight with moving a laser beam emitting tube 3 to the target point C of the above the surface for object with revolution (gamma) and angle of elevation (delta) and the beam point is picked up by an image pickup camera 4. The distance information (gamma) from the position of the image of the above of the linear sensor thereof upto the projecting point C is then obtd. and the three dimentionl coordinates of the projecting point C is found by feeding to a computer 13 together with the values of the revolution (gamma) and angle of elevation (delta) of the laser beam emitting tube 3.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Application of the Invention The present invention relates to an apparatus for measuring three-dimensional (stereoscopic) coordinate values.

Problems with conventional technology Measurement of three-dimensional structure dimensions inside buildings etc. Measurement of the three-dimensional movement path of the grip part tip of the cut arm, etc.
This is necessary for creating motion program tapes for painted robots or three-dimensional working robots. It is cumbersome and time-consuming to extract these line group data from the drawing, and it is also not easy to obtain them through loggett teaching.

Therefore, there is a need to quickly and accurately determine three-dimensional coordinate values directly from the actual object through three-dimensional measurement. However, a three-dimensional coordinate measuring device that meets this demand has not yet appeared.

Purpose of the Invention In view of the above-mentioned current situation, the present invention aims to achieve three target points with a simple operation.
The present invention aims to provide a three-dimensional coordinate measuring device that can quickly measure dimensional coordinate values with optimal measurement accuracy.

Summary of the Invention The present invention irradiates a target surface with a laser beam, captures the irradiated light point with an image camera, and calculates the distance from the laser optical axis base point to the irradiated light point based on the position of the image on the linear sensor. The distance is determined, and the spatial position of the irradiation light point (target point) is calculated based on the turning angle and elevation angle of the laser optical axis, which are measured at the same time. In this case, the present invention is
A laser beam emitting tube whose optical axis is aligned with the elevation angle and an imaging camera with a linear sensor are installed side by side on a rotating/elevation body having a rotation angle and elevation angle transducer, and the main axis of the camera and the laser optical axis are aligned parallel to each other. The tilt can be varied depending on the position. The linear sensor holds its longitudinal imaging surface at a position orthogonal to the camera main axis. Further, the present invention provides a bidirectional sweeping motion to the imaging camera, and the sensing and
It has means for measuring the video generation point in a cell (bit), using the bit position information including the video as a coarse scale, and using the measured value as a fine scale.

Hereinafter, the present invention will be specifically explained with reference to illustrated embodiments.

Example FIG. 1 is a block diagram showing a basic embodiment of the present invention.

A horizontal board (2) that can rotate in a horizontal plane on the base (1)
) has a trunnion bearing αQ, and supports the equipment in a vertical plane so as to be vertically rotatable. The equipment has a laser beam emitting tube (3) and a linear sensor type imaging camera (4) above it. Laser beam launch tube (3
) and the laser optical axis OP are made to coincide with each other. The main axis NR of the imaging camera is on the same plane as the laser optical axis OP, but both are configured to have a variable inclination angle θ from their mutually parallel positions. The principal point N of the optical system of the camera is set at a constant interval e in the direction perpendicular to the laser optical axis, such as the base point of the laser optical axis OP, that is, the trunnion support point 0.

“The turning angle τ in the horizontal plane and the elevation angle δ in the vertical plane are measured by the turning angle transducer (8) and the elevation angle transducer (9), respectively.Transducer (8)
, (9) may be of any type as long as it converts the rotation angle into an electrical signal, but here it is a potentiometer type.

To use this device, the laser beam emitting tube (3) is rotated (τ) and elevated (δ) to irradiate the target point C on the target surface with visual observation, and the light point is captured by the imaging camera. Caught in (4). The position of the image on the linear sensor and the distance information r to the projection point C are sent to the computer along with the values of τ and δ to calculate the three-dimensional coordinates of the 0 point (described later). reference). In this case, the target surfaces are limited to those close to each other, such as indoors, inside a vehicle, and the work surface of a robot, considering the purpose of use of the device, and are mainly surfaces such as tables, wooden objects, and painted metal surfaces. Therefore, since the laser irradiation point does not reflect in a fixed direction like a mirror surface, but reflects diffusely, the irradiation point can be visually confirmed as a re-emission point, and distance can be measured.

FIG. 2 is an analytical diagram showing the relationship between the laser optical axis and the optical system of the imaging camera. In the figure, parts corresponding to those in FIG. 1 are given the same reference numerals. For convenience of explanation, the inclination angle θ between the camera main axis (2) and the laser optical axis OP is exaggerated in the illustration. The turning angle τ is the rotation angle around the vertical axis 02, and the elevation angle δ is the rotation angle around the horizontal line OH. B is a linear sensor whose longitudinal imaging surface is held at a position perpendicular to the main axis (2) of the force-punch roller. The linear sensor has an external shape as shown in FIG. In FIG. 3A, a indicates the length of the longitudinal imaging surface or sensing unit, and b indicates its width. The sensing unit has m sensing units with a pitch of p, as shown in Figure 3B (enlarged view).
Consists of cells (m bits). That is, there is a relationship of a=mp.

Again in FIG. 2, . is the distance in the perpendicular direction from the laser optical axis base point O to the principal point N of the Katara optical system, and θ is the variable angle formed by the camera principal axis 2 and the laser optical axis OP. Here, in general, the following relationship holds true in the imaging camera as shown in FIG.

W = w L / f ・・・・・・・・・(
1) However, W is the height or width of the subject, W is the imaging height or width, L is the distance between the subject and the principal point of the lens, and f is the focal length of the lens.

Also, if the angle of view of the lens is 2α, −α= w/2 L = v/2 f ・−・−=−
(2) (1) , (2) yoF) w,,' W
= L / f = (3) Therefore, the triangle with the height L of the base W1 on the outside object side and the height f of the base W1 on the imaging side
The triangles have a similar relationship as they have a common angle of view of 2α with the principal point N as a boundary. Therefore, in FIG. 2, limit lines NS2 . If you draw NS, this is the limit line on the subject side, and on the imaging side,
An imaging plane of length W is included at a position at a focal length f from the principal point N.

t is the intersection of the NS and NS2 lines with the laser optical axis op.

and t2, points 12 and 11 become the upper and lower (or both sides) limit points of the external object to be irradiated with the laser beam. This is also a limitation on both sides of the image sensor. On the imaging side, since the sensor is installed in advance to the full height or width of W, w = a, and the external subject position is t, y)t.
2, the position of the irradiation light point on the imaging side on the sensor also changes from point q1 on the opposite side of the optical axis OP to q2 with respect to the main axis wind.
Move up to. In other words, suppose that the target point is irradiated with a laser beam at an arbitrary point C between t and t2, and a straight line passing through this point and perpendicular to the camera main axis ■ is connected to OS1.
The intersection with ゜0S2 is 41. d2 and the midpoint of d1d2 is g, then d1d2W + gN ''L.By equation (3), on the base W starting from the 61st point of the isosceles triangle with the base w1 and the height L. The position of the 0 point is analogously determined as one point on the base W starting from the 91st point of the isosceles trigonometric triangle with the base w1 and the height f.Therefore, the value r of the linear sensor starts from tl. The 0 point on the line segment leading to point t2, in other words, represents the OC on the optical axis op, that is, the straight line distance Lh to be sought (see below).
and Ot2 often indicate the lower and upper limits of Lh that can be measured by the camera on the optical axis OP.

The upper and lower limits of Lh are determined theoretically as follows.

tan(#+(X) <”h<-(6,) ・”--
(4) This is a case where θ+e+α, w (=a) are constant, but by making θ variable and keeping the others constant, distance measurement can be switched between long-distance mode and short-distance mode. Figure 5 is an explanatory diagram of the switching, where Figure 5A is the long distance mode (θ=01) and Figure 5B is the short distance mode (θ=01).
02) is shown. At this time, θ1>θ2. If used in such a switched manner, there is an advantage that all the distances F"i') near sensor F"i") can be made to correspond to the entire range of distances between the upper and lower limits of the measurement range in each case.

As shown in FIG. 7, the spatial coordinate values x+y, z of the 0 point are determined from the transducer direction and the δ value.

The calculation of equation (6) is also performed in the computer's head, and the three-dimensional coordinate value X + )' + Z of the 0 point is immediately determined.

Although the above example has been shown in which an equipment holder having an imaging camera and a radar launch tube is supported on a trunnion portion αO of a swinging/elevating body having a swing angle and elevation angle transducer, other configurations may also be adopted. In Figure 8, CI) measures the inclination angle of the laser beam.
They are arranged to produce a phase difference of the cycles. These two outputs are converted into positive and negative pulse trains through an attached waveform shaping circuit wf, and an elevation angle δ is calculated in a counting calculator C1 including a reversible counting circuit.

The geomagnetic transducer (2) consists of horizontal magnetic field measuring devices H1 and H1 and an attached azimuth angle calculator C2. A Hall element type magnetic flux detector can be used as the horizontal magnetic field measuring devices H, Hl. In the Hall element type magnetic flux detector, as shown in Fig. 10C, a constant current I is passed through a rectangular (x-y axis) Hall element small piece in the HOX axis direction, and a magnetic flux F is passed in two axes directions perpendicular to the X+3' axis. When given, a voltage output V proportional to the magnetic flux F is obtained from the voltage terminal provided in the y-axis direction. Such a Hall element type magnetic flux detector is used for the horizontal magnetic field measuring device H2 in FIG. 10A, one H1 being of a fixed type and the other H1 being of a pendulum type. For fixed Hl, when the X-7 side of the rectangular pellet is pasted in the vertical plane containing the laser optical axis OP1 and the camera main axis ■, the horizontal magnetic flux component Fx is always perpendicular to the vertical plane containing the OP line and the countersunk line. is calculated and outputted from the v1 terminal. On the other hand, the pendulum-type Hl supports one of the X-7 axes of a rectangular pellet at the axis perpendicular to the vertical plane including the op line and Weight m
Add 2 to make pellets! If the −7 plane is always held in a vertical position regardless of the elevation angle, the other horizontal magnetic flux component Fy which is orthogonal to FX beyond the v2 terminal can be found. As shown in Figure 10, these Fx and Fy values are the sine of the horizontal magnetic force FH in the magnetic north N direction, so input both outputs to the azimuth calculator C2 and calculate τ=-(Fy/Fx). The azimuth angle τ can be obtained from this.

First, referring to Figures 2 and 5, set the main axis of the camera optical system.
The upper and lower limits of distance measurement can be set by the inclination angle θ between In this case, the evenly spaced sensing cells (bits) of the linear sensor correspond to the asymmetric distance-increment digits of the linear sensor, which correspond to 1's. This means that the distance measurement is stepwise and the distance increment digit corresponding to each bit of the linear sensor gives a limit to the measurement resolution at each distance. Therefore, in order to further improve the accuracy of distance measurement, the distance increment digits corresponding to the light point imaging pits of this linear sensor are used as coarse distance scale information, and the actual light points (image ) and use this as fine distance scale information.

FIG. 11 is an explanatory diagram showing the relationship between the laser optical axis and the camera posture. In this figure, the same reference numerals are given to the parts already described. As described with reference to FIG. 2, ot2 and ot indicate the upper and lower limits of the measurable distance on the optical axis OP, and the distance from otl to bot2 corresponds to the measurement pit of the linear sensor B. When the linear sensor has an m-pit configuration, the starting point is b(1) pit (LSB) at the end opposite to the optical axis OP, and the ending point is the m-th b-bit (MsB). In addition, each bit string is a distance increment digit string ΔR1 (LSB) of m pits from the lower limit Ot of the target distance to the upper limit ot2,
..., corresponds to ΔRrn (MSB).

Therefore, if the incremental sum of distance increment digits corresponding to r bits of the linear sensor is R, then Rr='fΔ
R...Song (7) Also, 1. The distance Lh to the irradiation light point C is Lh=O11+
Rr curve straight 8) The distance Lh corresponding to the r bit of this linear sensor is
Linear sensor length w1 total number of bits m1 focal length jig
f, distance e1 inclination angle θ between optical system principal point N and laser optical axis thick point 0/? It can be calculated theoretically as a parameter, or it can also be obtained from a table. Now, let this be L), =f (r; w* m + f* @
+θ)・Song interval (9). (7), (8),
From equation (9), the incremental value of the distance increment digit ΔR corresponding to each bit of the linear sensor can be determined.

In general, due to the truncated effect due to the measurable distance lower limit due to θ, the distance increment digits ΔR corresponding to a linear sensor's evenly spaced bit string will give a diverging asymmetric distance increment digit scale. Also, this Δ
R indicates the limit of measurement resolution at measurement distance Lh. An example of the relationship between the bit r of the linear senna and the increment value Δr1 distance Lh of the corresponding distance increment digit is shown in the following table. However, f=40m+,
w=6.646mm.

m=384, e=48 mm, and θ=1.8°.

Table r (bit) Lh (gourd) ΔR (kaku) -512 (lower limit of measurement) - 1923,00262 2883673・93 384 4193 (upper limit of measurement) 123For general use of distance measurement, the OR7 value of formula (7) It can be used as is, but if you need to further improve accuracy,
Rr is set as a coarse scale, and the position of an actual image light spot within ΔRr is searched and this is set as a fine scale. For this reason, among the parameters mentioned above, with the mutual distance e between the optical system principal point and the laser optical axis reference point as the center, the standard width is the increase or decrease of e corresponding to 1 bit length of the linear degree sensor. , giving the linear sensor (and thus the camera) an up and down sweeping motion of one bit length or some bit length.

Then, output generation and extinction points in non-light receiving cells adjacent to the front end and rear end of a single bit (sensing cell) containing an image light spot or a plurality of sensing cell arrays are detected in accordance with the sweep cycle. do. This determines the actual position of the image light spot, and uses this as fine scale information when the digits corresponding to distance increments of the linear sensor are used as coarse scale.

FIG. 12 is an explanatory diagram showing the positional relationship of light spots projected on the cell (bit) row of the sensing unit of the near sensor. If there is a light spot in one unit bit b(r) and b(r-j
), Figure 12C shows the case where the light spot spans three unit pics) b, b and b(r-f), respectively (r+f) (r). In the case of FIG. 12B or C, output is generated from two or three adjacent bits. The light emitting point on the target surface is a re-emitting point due to diffuse reflection, so if the target surface is rough, the light point expands and the light receiving point (image) spreads over three bits as shown in Figure 12C. It is not uncommon for the data to span several or more bits. In such cases, it is necessary to find the center point of the image. To do this, it is necessary to find out at which position the output of the image light point occurs among the leading and trailing bits of the single bit or multiple bit string of the linear sensor where the output occurs. It is necessary to measure whether it has disappeared. However, since it is difficult to measure directly, a sweeping motion is applied to utilize cells that do not receive light.

FIG. 13 is an explanatory diagram showing an example of a sweeping method.

In this figure, the image light spot exists in the range A, and the linear sensor's r-nth frame)b(1) to b(n) (r)n) output is generated. shall be.

By applying a constant velocity sweep motion of Δθ in the positive and negative directions to the interval e with the position of the set interval e between the optical axis and the camera principal point as the zero point, the 1-bit length of the linear sensor is adjusted in accordance with the output generation and extinction points. so that the scale moves only by Then, the upper bit b(
r+1) and lower pitch) b(n-1), distance increasing side round trip (O~+Δe-0) and distance decreasing side round trip (0~-Δe
.about.0), an output generation range of η1% and η2chi occurs in each reciprocating cycle. For example, as shown in FIG. 13, an output generation range of 75 chi occurs in the b(r+1) bit in each round trip cycle of (0~+Δe~0), and in a round trip cycle of (O~-Δe−0), In each case, when an output generation range of 90 bits occurs in b(n-1) bits, and r=11z and n=9, the number of fine and coarse scales is as follows. The upper limit of the boundary position where the image light spot exists is 11 + 0.75 = 11.75, and the lower limit is 9 + (1
-0.9 piece becomes 9J. Generally, the target (target) image is considered to be in the middle position between the upper and lower limits, so the position of the image on the scale is (9, 1 + 11.75)/2-10.
It can be expressed with 425 fine and coarse scales. Also, if bit r and pitch n are the same, for example, r=n==8, then the fine/coarse scale is 8+(0,75-0,1)/2=8
．． It becomes 325.

In addition, in the upper part, the distance was changed (swept) by Δe corresponding to the scale movement of 1 bit length at the image light spot position (r bit), but if Δe is small, Δe is set to 1 unit and this is changed. Sweeping motion may be performed up and down (or on both sides) at a constant speed of N units. FIG. 14 is an explanatory diagram showing the sweeping method in this case. In this case, as shown in the figure, the distance increasing side reciprocating cycle is (0~Δ・~2Δe~...NΔe
~(N-1)Δe~...2Δe~Δe -0), and the distance decreasing side reciprocating cycle is (0-Δe~-2Δe~・
...-NΔe~-(N-1)Δe...-2Δe~-Δ
・~O) Tonal (7'c, Fig. 14 shows the case where N=3). In this case, ON is r+N pit and n-
Δe that gives a movement of 1 bit and t length at each position of N bits is t! For example, it is necessary to keep the value N<10 so that the same value can be obtained. The corresponding bits for searching the output generation range during the positive/negative sweep movement of Nle above are b(r+1) and t searched during the positive/negative reciprocating sweep with Δe as one unit.
'(n-1) bits are sequentially shifted up and down by N bits, the output generation range of each bit is determined for each pitch of the round trip cycle on the increasing side of Δe, and this is set as η1,
Further, this is determined for each pitch of the reciprocating cycle on the Δe decreasing side and set as ηj, and the average of the total number 2N of each reciprocating cycle is determined and this is set as η1. Let it be η2. That is, Ση
, 72N=η1 1=0 ~ Δe, Δe ~ 2Δe , , , , (N
-1)Δe−NΔe.

NΔe~(Nl)Δel"'+2Δe~Δe, Δe~0
;Σηj/2N=η2 j=θ〜−Δe, −Δe〜−2, Δe, −, −(N−1
)Δe~-N/je.

−NΔe〜−(N−1)Δer”・+−2Δe〜−Δe
, -Δe~0; b(r+1) when these η, η are reciprocated with the previous Δe.

, η4. of the output generation range in 12 b(n-1) bits. By treating it in the same way as η2, a fine and coarse scale can be obtained.
.

Ru.

Effects of the Invention The present invention can measure the spatial (three-dimensional) coordinates of a target point with a simple operation of irradiating the target point on the target surface with a laser beam, so it can be used as a three-dimensional digitizer quickly for indoor purposes, etc. It is possible to measure and draw the dimensions of the three-dimensional construction part or the three-dimensional movement path of the grip part tip of the rodet arm. Therefore, it becomes easy to create a motion program tape for painting openings, three-dimensional working rodets, and the like.

Further, by switching the inclination angle between the camera main axis and the laser optical axis depending on the distance to the target point, the measurement distance range can be set to the optimum measurement accuracy.

Furthermore, the distance increment digit corresponding to the image light spot bit of the linear sensor is used as the coarse scale information of the distance, the position of the actual image light spot is searched for in the corresponding distance increment digit, and this is used as the position of the image light spot of the distance. By using fine scale information, the accuracy of distance measurement can be further improved.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram showing a basic embodiment of the present invention, Figure 2 is an analysis diagram showing the relationship between the laser optical axis and the optical system of the imaging camera, Figure 3 is a diagram showing the linear sensor, and Figure 3 is a diagram showing the relationship between the laser optical axis and the optical system of the imaging camera. Figure A is a plan view, Figure 3B is an enlarged view of the main parts, Figure 4 is an explanatory diagram of the imaging camera optical system, Figure 5 is an explanatory diagram of switching between long-distance and short-distance modes, and Figure 5A is a long-distance view. Figure 5B is a diagram of the short distance mode, Figure 6 is a curve diagram showing the relationship between the output bit of the linear sensor and the measured distance, and Figure 7 is the measured distance Lh and the laser optical axis. An explanatory diagram for determining the XYZ coordinate values of the target point C from the turning angle τ and the elevation angle δ, FIG. 8 is an external view showing another embodiment of the present invention, and FIG. 9 shows still another embodiment of the present invention. External view, Figure 10 is an explanatory diagram showing the tilt transducer and geomagnetic transducer, Figure 11 is an explanatory diagram showing the relationship between the laser optical axis and the camera posture, and Figure 12 is an explanatory diagram showing the relationship between the laser optical axis and the camera attitude.
The figure is an explanatory diagram showing the positional relationship of images appearing on the linear sensor, Fig. 13 is an explanatory diagram showing an example of a sweeping method to obtain fine scale marks, and Fig. 14 is an explanatory diagram showing another example of the sweeping method. It is a diagram. (8)... Turning angle transducer, (9)... Elevation angle transducer, (a)... Turning/elevation body, (
3)... Laser beam launch tube, OP... Laser optical axis, (4)... Linear sensor type imaging camera, ■...
・Camera main axis, θ...Variable tilt angle, B...Linear
Sensor, C... Irradiation light point (target point), r... Image position on the linear sensor, Lh... Distance from the laser optical axis base point to the irradiation light point, τ... Turning angle, δ...
Elevation angle, η...measured value, b(r+1) l b(r)
+b(r-1), b(n) 1b(n-D '''Sensing cell (bit) position.

Claims (1)

[Scope of Claims] 1. A laser beam emitting tube and a linear sensor whose laser beam axis is aligned with the elevation axis of a rotating/elevation body having transducers that measure the rotation angle in the horizontal plane and the elevation angle in the vertical plane, respectively. type imaging cameras are arranged side by side, the laser optical axis and the camera main axis can be tilted variablely from their parallel positions, the longitudinal imaging surface of the linear sensor is held at a position orthogonal to the camera main axis, and the A laser beam is irradiated onto the target surface by a laser beam emitting tube, the irradiated light point is captured by the above-mentioned imaging camera, and the distance from the above-mentioned laser beam axis base point to the irradiated light point is determined from the position of the image on the linear sensor. A three-dimensional coordinate measuring device that calculates the spatial position of a target point based on the measured turning angle and elevation angle of the laser optical axis. 2. A laser beam emitting tube whose laser beam axis is aligned with the elevation axis and a linear sensor type imaging camera are arranged in a rotating/elevating body having a transducer that measures the angle of rotation in the horizontal plane and the angle of elevation in the vertical plane. the laser beam axis and the main axis of the camera can be tilted variably from their parallel positions, the longitudinal imaging surface of the linear sensor is held at a position orthogonal to the camera main axis, and the laser beam is emitted by the laser beam emitting tube. Irradiate the target surface with
The irradiated light point is captured by the imaging camera, and the distance from the laser optical axis base point to the irradiated light point is determined based on the position of the image on the linear sensor, and this and the measured turning angle and elevation of the laser optical axis are determined. In a three-dimensional coordinate measuring device that calculates the spatial position of a target point based on the angle, the distance from the laser optical axis base point to the irradiation light point is calculated based on a specific value of the interval between the laser optical axis base point and the camera optical system principal point. applying a sweeping motion in both directions to said camera to produce a displacement on said linear sensor corresponding to a distance corresponding to one sensing cell length or multiple sensing cell lengths; Measure the image generation and extinction points in the non-light receiving cells adjacent to the front end and rear end cells of the sensing cell or the plurality of sensing cell rows, respectively, corresponding to the sweep cycle, and use this measurement value as a value that includes the image. Fine scale when single or multiple sensing cell position information is used as a coarse scale representing the distance 3
Dimensional coordinate measuring device.