JPH09113224A - Mark for measuring three-dimensional position posture and method and device for measuring three-dimensional position posture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify an image pick-up unit and reduce its production cost. SOLUTION: Mark pictures 3a and 3b, which are formed on the objective surface of an object 1 to be measured according to a mark 3 having two straight lines not parallel to each other, are allowed to be image-formed on an image forming surfaces 7a and 7b provided with one-dimensional optical sensors 6a, 6b, 6c, and 6d, thereby measuring the three-dimensional position and posture of the mark 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-dimensional position / orientation measurement mark, and a three-dimensional position / orientation measurement method and device, and more particularly, to simplifying the measurement of the position and orientation of a moving body such as a manipulator and a rotating belt. The present invention relates to a mark for three-dimensional position / orientation measurement, a three-dimensional position / orientation measurement method and a device for cost reduction and improved handling.

[0002]

2. Description of the Related Art When gripping and moving an object with a manipulator, the position and orientation of the manipulator must be measured at high speed and with high accuracy. 2. Description of the Related Art As a conventional three-dimensional position and orientation measuring device, there is a device using an image pickup means such as a television camera for performing visual feedback control. According to this three-dimensional position / orientation measuring apparatus, an image of an object to be measured is picked up by an image pickup means such as a television camera to generate three-dimensional position / orientation information, and the coordinate system in which the three-dimensional position / orientation is fixed to the environment. , And the manipulator is moved to the target position in the coordinate system.

As a method for measuring such a three-dimensional position and orientation, a stereo method for picking up three characteristic points of an object to be measured by two image pickup means is generally known. It is 2 in Kaihei 3-135718 publication.
A method is disclosed in which parallel lines of a book are imaged by a stereo method to grasp a position and orientation in three dimensions.

However, according to this three-dimensional position / orientation measuring apparatus, a two-dimensional CCD sensor is used as an image pickup means such as a television camera, and the data capturing speed of one screen is 1/30 seconds or 1/60 seconds. Is. This is extremely slow compared to the fact that the feedback cycle time of the motor controller of the manipulator is generally 1/1000 second or less, and cannot be applied to high-speed positioning work. Also,
Since the number of pixels on one screen is about 500 × 500, the resolution is not sufficient, and since the amount of information to be processed is large, a dedicated processing circuit is required for speeding up, resulting in an increase in cost.

On the other hand, a position measuring device for measuring the position and orientation of a measuring object by measuring the reference position of the measuring object is disclosed in Japanese Patent Laid-Open No. 64-18001.

In the position measuring device disclosed in Japanese Patent Laid-Open No. 64-18001, a point light source such as a miniature light bulb is attached to a reference position of an object to be measured, and the point light source is condensed by a condensing optical system to condense light. The split light beam is split by a beam splitter,
The divided light beams are detected by two-dimensional one-dimensional sensors that are orthogonal to each other, and the sensor signals are input to the corresponding position detection circuits to measure the position of the measurement target.

[0007]

However, Japanese Unexamined Patent Publication No.
According to the position measuring device of Japanese Patent No. 18001, various optical components including an imaging lens, a kamaboko lens, and a beam splitter are required, so that the configuration becomes complicated and the cost becomes high. In addition, since a point light source such as a miniature bulb is required, care must be taken in handling to prevent breakage.

Therefore, it is an object of the present invention to provide a three-dimensional position / orientation measuring mark and a three-dimensional position / orientation measuring method and apparatus which can be simplified.

Another object of the present invention is to provide a mark for three-dimensional position and orientation measurement, and a method and apparatus for measuring three-dimensional position and orientation, which can reduce the cost and improve the handling property.

[0010]

To achieve the above object, the present invention has, as a first feature, including two non-parallel line segments formed in a predetermined plane region to provide one intersection. The one intersection is a reference point for position measurement, and the two line segments provide a three-dimensional position / orientation measurement mark that is a reference line for attitude measurement.

In the above three-dimensional position and orientation measuring mark, the intersection may be provided within a predetermined area, and
It may be provided outside the predetermined area, and also two line segments,
And outside the area surrounded by at least two detection lines intersecting the two line segments, and
It may be provided inside the area surrounded by the two line segments and at least two detection lines intersecting the two line segments.

The present invention has a second object to realize the above object.
As a feature of the above, a mark including two non-parallel line segments that provide one intersection point and that is displaced according to the displacement of the measurement object is formed on the first plane on the measurement object, and the mark is formed on the second plane. At least two one-dimensional photosensors are arranged, line segment images of the two line segments included in the mark are formed in two directions on the second plane, and the at least two one-dimensional photosensors are formed in the longitudinal direction. A light-reception signal representing a light-reception intensity distribution of the two, and the positions of the two line-segment images on the at least two one-dimensional photosensors are calculated based on the light-reception signal.
Three-dimensional calculation of a position of the intersection point provided by two line segments included in the mark and a posture of the two line segments included in the mark based on the positions on the at least two one-dimensional optical sensors A position and orientation measurement method is provided.

In the above three-dimensional position and orientation measuring method,
The mark may be defined by defining the edge of the object to be measured as at least one line segment of two line segments, and an opening for light transmission defined as at least one line segment of the two line segments. The measurement may be performed by providing the measurement target, or by applying, pasting, or coating a material having a reflectance different from that of the measurement target and defining it as at least one line segment of two line segments. Good, and also to make the measurement object light-transmissive, and to apply, paste, or cover the measurement object with a material having a light transmittance different from that of the measurement object, so as to form at least one line segment of two line segments. You may define and go. Further, at least two one-dimensional photosensors are arranged on at least two on the third and fourth planes, respectively, and line segment images of two line segments included in the mark are formed on the third and fourth planes, respectively. You may do it.

In order to achieve the above object, the present invention provides a third aspect.
And a mark that includes two non-parallel line segments that are formed on a first plane of the measurement object and that provide one intersection, and that is displaced according to the displacement of the measurement object.
An image forming unit that forms line segment images of the two line segments included in the mark in two directions on a second plane; and a line segment image that is arranged on the second plane and is based on the line segment images of the two line segments. And at least two one-dimensional photosensors that output a light-reception signal indicating a light-reception intensity distribution in the longitudinal direction, and the positions of the two line-segment images on the at least two one-dimensional photosensors are calculated based on the light-reception signals. First computing means, the position of the intersection point provided by the two line segments included in the mark based on the positions on the at least two one-dimensional optical sensors, and the two lines included in the mark There is provided a three-dimensional position and orientation measuring apparatus including a second calculation means for calculating the orientation of the minute.

In the above three-dimensional position and orientation measuring device,
The mark may be configured such that at least one line segment of the two line segments is constituted by an edge of the measurement target, and at least one line segment of the two line segments is a light beam formed on the measurement target. It may be configured by an aperture for transmission, and at least one line segment of two line segments is coated with a material having a reflectance different from that of the measurement target,
You may make it comprised by sticking or covering. Also, the measurement object is made of a light-transmissive material, and the mark is at least one of the two line segments.
The two line segments may be formed by applying, pasting, or coating a material having a light transmissivity different from the light transmissive material on the measurement target. The image forming means has a configuration for forming line segment images of two line segments on the third and fourth planes, respectively, and at least two one-dimensional photosensors have at least two on the third and fourth planes, respectively. It is also possible to have a configuration in which two are arranged.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION A three-dimensional position and orientation measuring mark, and a three-dimensional position and orientation measuring method and apparatus according to the present invention will be described below with reference to the drawings.

FIG. 1 shows a third embodiment of the present invention.
A three-dimensional position / orientation measuring apparatus is shown, in which an object to be measured 1 having a mark 3 formed on an object surface 2 and an object surface 2 including the mark 3 are shown.
Imaging lenses 4a and 4b for condensing reflected light of 2 and imaging marks 3a and 3b formed on the two imaging surfaces 7a and 7b by condensing the imaging lenses 4a and 4b 1
1 based on the timing signals output from the three-dimensional photosensors 6a, 6b and 6c, 6d and the synchronization signal generation circuit 10.
Driving circuits 11a, 11b, 11c, 11d for driving the dimensional optical sensors 6a, 6b, 6c, 6d, and amplifiers 12a, 12b for amplifying light intensity signals output from the one-dimensional optical sensors 6a, 6b, 6c, 6d, 12c, 12d, A / D converters 13a, 13b, 13c, 13d for converting the amplified light intensity signal into a digital signal, and writing of the light intensity signal converted into the digital signal from the memory control circuit 15 Memory 14 for storing based on signals
And a processor 16 for inputting the light intensity signal output from the memory 14 based on the read signal output from the memory control circuit 15 to calculate the three-dimensional position and orientation of the measurement object 1, and 3 in the processor 16. The display unit 17 displays the calculation result of the dimensional position and orientation.

The mark 3 has non-parallel straight lines L ₁ and L ₂ having an intersection point P, and a paint having a reflectance different from that of the target surface 2 is applied to the surface, or a mark printed with ink is printed on the target surface. It may be formed by adhering it to No. 2 or by adhering a member made of a material having a reflectance different from that of the target surface 2. In the present embodiment, the mark 3 is formed by applying black paint on the surface of the white target surface 2.

There may be three or more straight lines L ₁ and L ₂ of the mark 3, and attention should be paid to two lines satisfying the condition. These straight lines may be continuous lines or discontinuous lines, and a line segment having a predetermined length may be defined.

In the configuration of FIG. 1, the measurement object 1 is reflected by light emitted from an illumination unit (not shown), so that mark images 3a and 3b based on the shape of the mark 3 provided on the object surface 2 are formed on the image plane. 7a, 7b. That is, the mark images 3a and 3b are condensed by the image forming lenses 4a and 4b to form an image forming surface 7a on which the one-dimensional optical sensors 6a and 6b are provided, and an image forming surface 7b on which the one-dimensional optical sensors 6c and 6d are provided. Image on. One-dimensional optical sensor 6a, 6
Reference numerals b, 6c and 6d are one-dimensional CCDs, light receiving element arrays and the like, and mark images 3a and 3b formed on the image forming surfaces 7a and 7b.
Based on the light intensities of the pixels at the positions intersecting with each other and the light intensities of other portions, light intensity signals representing the distribution of the light receiving level are output to the amplifiers 12a, 12b, 12c, 12d. The light intensity signals amplified by the amplifiers 12a, 12b, 12c and 12d are A / D converters 13a, 13b, 13c,
It is converted into a digital signal in 13d. The memory control circuit 15 outputs a write signal and a read signal according to the control signal output from the processor 16, stores the light intensity signal in the memory 14 based on the write signal,
The light intensity signal is output to the processor 16 based on the read signal. The processor 16 calculates the three-dimensional position and orientation of the measuring object 1 based on the light intensity signal input from the memory 14, and outputs the calculation result to the display unit 17.

FIG. 2 shows the correspondence between the object coordinate system and the two-dimensional coordinate system on the image forming planes 7a and 7b. The image forming lens has virtual points O _L and O _R on the image forming planes 7a and 7b. The optical system configuration is arranged in front of (not shown), and in the following description, this optical system configuration will be used for ease of explanation.

The object coordinates are (x, y, z), the two-dimensional coordinates on the image plane 7a on which the one-dimensional photosensors 6a, 6b are provided are (h _L , v _L ), and the one-dimensional photosensors 6c, 6d are _Let the two-dimensional coordinates on the provided image plane 7b be (h _R , v _R ),
Assuming that the camera parameter of the image pickup unit having the one-dimensional photosensors 6a and 6b is C and the camera parameter of the image pickup unit having the one-dimensional photosensors 6c and 6d is B, the camera parameters C and B are expressed by the equations (1) and (2). ) By

[0023]

(Equation 1)

[0024]

(Equation 2) It is expressed as

The object coordinates and the two-dimensional coordinates on the image planes 7a and 7b are [fh _L fv _L f] ^t = C [x, y, z, 1] ^t −− using the parameters f and g. -(3) [gh _R gv _R g] ^t = B [x, y, z, 1] ^t --- (4). Here, [] ^t represents a transposed matrix.

The straight lines L ₁ and L ₂ of the mark 3 are formed by the image plane 7a.
The mark image 3a having the intersection point P _L and the straight lines L _1L and L _2L is formed by forming an image on the image plane, and the mark image 3b having the intersection point P _R and the straight lines L _1R and L _2R is formed by forming an image on the image forming surface 7b. To form.

FIG. 3A shows the mark image 3a formed on the image forming surface 7a, and FIG. 3B shows the mark image 3b formed on the image forming surface 7b. The one-dimensional photosensors 6a and 6b. From the points A ₁₁ and A ₂₁ where the mark image 3a intersects with the mark image 3a, and the straight line L _1L of the mark image 3a is restored, and from the points A ₁₂ and A ₂₂ where the one-dimensional optical sensors 6a and 6b intersect the mark image 3a, Straight line L
_2L is restored. Mark image 3b formed on the image plane 7b
Similarly, the straight line L _1R of the mark image 3a is restored from the points D ₁₁ and D ₂₁ where the one-dimensional photosensors 6c and 6d and the mark image 3b intersect, and the one-dimensional photosensors 6c and 6d and the mark image 3b are A straight line L of the mark image 3b from the intersecting points D ₁₂ and D _22
2R is restored.

FIG. 4 shows the mark image 3a on the image plane 7a.
_Shows the relationship between the positions of the straight lines L _1L and L _2L and the signal outputs of the one-dimensional photosensors 6a and 6b. The straight lines L ₁ and L ₂ of the mark 3 are lines having a constant width, and their images L _1L and The sensor value is low at the L 2 _L portion. Therefore, the positions q _ij (i = 1, 2, j = 1, 2) of the straight lines L _1L , L _2L of the mark image 3a are
As shown in FIG. 5, using the pixel data in the vicinity of an appropriate threshold value I or less, for example, the barycentric position of the shaded portion is obtained. The barycentric position q _{ij at} that time is calculated by, for example, Expression (1).

[0029]

(Equation 3) Here, D (q) represents the output value of the pixel q, and Db represents the background level.

Further, the i-th one-dimensional optical sensor is formed on the image plane 7
In the two-dimensional coordinate system at a, [h_L, V_L]^t= Q [a_Li, B_Li]^t+ [C_Li, D_Li]^t (I = 1, 2) --- (6) (where [a_Li, B_Li]^tIs the pixel pitch
Vector, [c_Li, D _Li]^tIs at the end of the one-dimensional optical sensor
The center coordinates of the pixel, q is the pixel number. )
Position of the mark image 3a on the one-dimensional optical sensors 6a and 6b
Is the two-dimensional coordinate (h_L,
v_L) Is converted to. Therefore, A₁₁~ A_{twenty two}Is q₁₁~ Q_{twenty two}
Is obtained by substituting in the equation (2). And A
_ij(H_ij, V_ij), The straight line L_1L, L_2LImage of
The equation of the straight line on the surface 7a is L_1L: (H_{twenty one}-H₁₁) (V_L-V₁₁) = (V_{twenty one}-V₁₁) (H_L-H₁₁) --- (7) L_2L: (H_{twenty two}-H₁₂) (V_L-V₁₂) = (V_{twenty two}-V₁₂) (H_L-H₁₂) --- (8). D₁₁~ D_{twenty two}For the same calculation
Therefore, the straight line L_1R, L_2RStraight line on the image plane 7b of
The equation can be obtained.

Next, the mark image 3a obtained in the above process,
Mark 3 based on straight lines L _1L , L _2L , L _1R and L _2R of 3b
The position of the intersection point P of the straight lines L ₁ and L ₂ is obtained. There are several methods for obtaining the line, for example, the line equation of the lines L ₁ and L ₂ of the mark 3 in the object coordinate system is obtained,
The intersection may be calculated. However, the calculated straight lines L ₁ and L ₂ may have a twist relationship due to a reading error or a model error of the image pickup device during image pickup. In such a case, the straight line L ₁ , L ₂ is the closest line L
It is also conceivable to set the midpoint between the positions on ₁ and L ₂ as the intersection point P.

As another method for obtaining the position of the intersection P of the straight lines L ₁ and L ₂ of the mark 3, the intersections P _L and L _1R of the straight lines L _1L and L _2L in the two-dimensional coordinate system of the image planes 7a and 7b. , L
There is a method of finding the intersection point P from the intersection point P _{R of 2R} based on the principle of triangulation. Below, the intersection point P based on the principle of triangulation
The calculation method of is explained.

First, the object coordinates of the target surface 2 and the image plane 7
Formula (3), which is a relational expression of two-dimensional coordinates of a and 7b, is developed. fh _L = C ₁₁ x + C ₁₂ y + C ₁₃ z + C ₁₄ --- (9) fv _L = C ₂₁ x + C ₂₂ y + C ₂₃ z + C ₂₄ --- (10) f = C ₃₁ x + C ₃₂ y + C ₃₃ z + C ₃₄ --- (11) (9) -f × (11) and (10) -f than × (11) 0 = (C 11 -C 31 h L) x + (C 12 -C 32 h L) y + (C 13 -C 33 h _{L) z + (C 14 -C} 34 h L) --- (12) 0 = (C 21 -C 31 v L) x + (C 22 -C 32 v L) y + (C 23 -C 33 v L) _{z + (C 24 -C 34 v} L) --- obtain (13). Further, by expanding the formula (4), gh _R = B ₁₁ x + B ₁₂ y + B ₁₃ z + B ₁₄ −−− (14) gv _R = B ₂₁ x + B ₂₂ y + B ₂₃ z + B _{24 −−} (15) g = B ₃₁ x + B ₃₂ y + B ₃₃ z + B ₃₄ −−− (16) From (14) −g × (16) and (15) −g × (16) 0 = (B ₁₁ −B ₃₁ h _R ) x + (B ₁₂ −B ₃₂ h _{R ) y + (B 13 -B 33} h R) z + (B 14 -B 34 h R) --- (17) 0 = (B 21 -B 31 v R) x + (B 22 -B 32 v R) y + obtain _{(B 23 -B 33 v R)} z + (B 24 -B 34 v R) --- (18). Among formulas (12), (13), (17) and (18),
For example, using equations (12) (13) (17)

[0034]

(Equation 4)

[0035]

(Equation 5) Then, F = QV --- (19), (h _L , v _L ) is the coordinate of P _L , and (h _R , v _R )
Is the coordinate of P _R , V = Q ⁻¹ F −−− (20) when the inverse matrix of Q exists, so the three-dimensional position of the intersection point P can be obtained.

There are four ways to select the three expressions based on the expressions (12), (13), (17) and (18). By calculating the expression (20) for each of them, and finally taking the average of the four ways. The intersection point P may be obtained.

Next, the posture of the measuring object 1 in three dimensions
The method of obtaining is explained. Appearance of measurement object 1 in three dimensions
Force is expressed by roll, pitch, yaw angle, Euler angle, etc.
Can be, straight line L of mark 3₁Direction vector r of₁When
Straight line L_TwoDirection vector r of_TwoBy identifying
Can be Below, the direction vector r₁And r _Two
Explain how to obtain.

In FIG. 2, the plane F _1L is the lens principal point O _L.
, The straight line L _1L of the mark image 3a and the straight line L of the mark 3
A plane including ₁ , a plane F _2L passes through the lens principal point O _L , a plane including a straight line L _2L of the mark image 3 a and a straight line L _{2 of the} mark 3, a plane F _1R passes through the lens principal point O _R , and the mark image 3 b plane including the straight line L ₁ of the straight line L _1R and the mark 3 of the plane F _2R
Passes through the lens principal point O _R, is a plane containing the straight line L ₂ of the straight line L _2R and mark 3 mark images 3b. Direction vector r
_{In obtaining 1} , the equation of the plane F _1L is obtained.

First, if f is deleted from equation (3), h_L= (C₁₁x + C₁₂y + C₁₃z + C₁₄) / (C₃₁x + C₃₂y + C₃₃z + C₃₄) --- (21) v_L= (C_{twenty one}x + C_{twenty two}y + C_{twenty three}z + C_{twenty four}) / (C₃₁x + C₃₂y + C₃₃z + C₃₄) --- (22) and these are straight lines L of the mark image 3a._1LEquation
Substituting into (7) and rearranging F_1L : A_1Lx + b_1Ly + c_1Lz + d_1L= 0 −−− (23) a_1Lx = n₁(C_{twenty one}-V₁₁C₃₁) -M₁(C₁₁-H₁₁C₃₁) B_1Ly = n₁(C_{twenty two}-V₁₁C₃₂) -M₁(C₁₂-H₁₁C₃₂) C_1Lz = n₁(C_{twenty three}-V₁₁C₃₃) -M₁(C₁₃-H₁₁C₃₃) D_1L= N₁(C_{twenty four}-V₁₁C₃₄) -M₁(C₁₄-H₁₁C₃₄) N₁= H_{twenty one}-H₁₁ m₁= V_{twenty one}-V₁₁ And from this, the plane F_1LNormal vector f of_1LIs
(A_1L, B_1L, C_1L) Is required. Can be calculated in the same way
Plane F by_2L, F_1R, F_2RNormal vector f of _2L,
f_1R, F_2RIs required.

By the way, the straight line L of the mark 3₁Is the plane F
_1LAnd plane F_1RDirection vector r₁
Is the plane F_1LAnd plane F_1RNormal vector f of_1L, F_1RAgainst
Is vertical, so r₁= F_1L× f_1R --- (24), similarly, the straight line L of the mark 3 is obtained._TwoIs the plane
F_2LAnd plane F_2RDirection vector r
_TwoIs the plane F_2LAnd plane F_2RNormal vector f of_2L, F _2RTo
And it becomes vertical, so r_Two= F_2L× f_2R --- (25) Also, the normal vector q of the target surface 2
Is the direction vector r₁And r₁To be perpendicular to
From q = r₁× r_Two --- (26)

Next, based on the normal vector q of the target surface 2 and the direction vector r ₁ of the straight line L ₁ obtained in the above process, the three-dimensional posture (roll, pitch, yaw angle) of the measuring object ₁ is obtained. The process of calculating is described below.

A unit vector r _1e of the direction vector r ₁ (r
_1x , r _1y , r _1z ) (where r _1x > 0) is parallel to the x-axis, and the unit normal vector q of the normal vector q
_If the posture of the mark 3 when _e (q _x , q _y , q _z ) (where q _z > 0) is parallel to the z axis is the reference posture,
The following relational expression is obtained. r _1x = cos (θ _r ) cos (θ _p ) −−− (27) r _1y = sin (θ _r ) cos (θ _p ) −−− (28) r _1z = −sin (θ _p ) −−− (29) q _x = cos (θ _r ) sin (θ _p ) cos (θ _y ) + sin (θ _r ) sin (θ _y ) −−− (30) q _y = sin (θ _r ) sin (θ _p ) Cos (θ _y ) −cos (θ _r ) sin (θ _y ) −−− (31) q _z = cos (θ _p ) cos (θ _y ) −− (32) Transforming equation (29). Thus, the pitch θ _p is θ _p = −sin ⁻¹ (r _1z ) −−− (33) From the equations (27) and (28), the roll θ _r is θ _r = tan ⁻¹ (r _1y / r _1x ) −−− (34) Further, by modifying the equation (32), cos (θ _y ) = q _z / cos (θ _p ) −− (35) Substituting the equation (35) into the equation (30), Expression (3
By substituting the pitch θ _p obtained in 3) and the roll θ _r obtained by the equation (34), the yaw angle θ _y is θ _y = sin−1 {(q _x −q _z · cos (θ _y ) tan (? _P )) / sin (? _R )} --- (36).

FIG. 6 is a flow chart showing the arithmetic processing steps in the processor 16, in which steps S ₁ ,
_{S 2, S 3, S 4} , S 5 at it is possible to obtain the position of the mark 3, Step _{S 1, S 2, S 3} , S 6, S 7,
It is possible to determine the attitude of the mark 3 in S _8, S _9.

As shown in FIG. 7 (a), the mark 3 may have a shape in which the straight lines L ₁ and L ₂ are separated from each other and there is an intersection (not shown) on the extension line thereof. As shown in, the shape may be crossed. Further, the straight lines L ₁ and L ₂ of the mark 3 are the read lines 18 by the one-dimensional photosensor.
Since it is only necessary to detect a straight line at a and 18b,
As shown in FIG. 7C, it may be discontinuous. Further, as shown in FIG. 7D, a mark formed by hollowing out straight lines L ₁ and L ₂ may be used. FIG. 7 (e)
As shown in FIG. 3, the marks 3 whose contour lines are used as the straight lines L ₁ and L ₂ may be formed. Further, the mark 3 may be formed by a groove or a convex portion. Alternatively, a linear light source may be used, or a fluorescent paint may be applied to form the light source. Further, if the measurement object 1 is light transmissive, the mark 3 may be formed by a member made of a material having different light transmissivity. Further, if the object to be measured is a thin member such as a plate, an opening is provided instead of the mark 3, the object to be measured 1 is sandwiched, and light leaking from the side opposite to the imaging unit 5 is emitted. May be detected.

FIG. 8 regards the contour lines of the mark shown in FIG. 7E as straight lines L ₁ and L ₂ and an image pickup unit (not shown).
Captured by the two straight lines L _1L having an intersection point P _L, L
It is used as a mark image 3a composed of _2L.
By providing a predetermined threshold value I for the signal output levels of the three-dimensional photosensors 6a and 6b, the linear position q _{11 of the} mark image 3a
to detect the q _22. The same parts as those in FIG. 4 are designated by the same reference numerals and reference numerals, and the duplicated description will be omitted.

FIG. 9 shows that non-parallel straight edges L ₁ ,
The object to be measured 1 having L ₂ is imaged by the imaging units 5a and 5b, and the edge images L _1L , L _2L ,
The edges L ₁ and L _{2 of the} measuring object 1 are detected by detecting L _1R and L _2R by the one-dimensional optical sensors 6a, 6b, 6c and 6d.
Can be used instead of the mark.

FIG. 10 shows a modified example of the arrangement of the one-dimensional photosensors 6a and 6b on the image plane 7, and as shown in FIG.
The two-dimensional optical sensors 6a and 6b are arranged non-parallel to each other, or (b)
The configuration may be such that they are arranged orthogonally.

FIG. 11 shows another modification of the arrangement of the one-dimensional photosensors 6a and 6b. In (a), the straight line L _1L is imaged on the one-dimensional optical sensors 6a and 6b, and the straight line L _2L is imaged on the one-dimensional optical sensors 6b and 6c. In (b), the straight line L _1L is imaged on the one-dimensional optical sensors 6a and 6b, and the straight line L _2L is imaged on the one-dimensional optical sensors 6c and 6d. In (c), the straight line L _1L is imaged on the one-dimensional optical sensors 6a and 6b, and the straight line L _2L is imaged on the one-dimensional optical sensors 6b and 6c. In (d), the intersection point P _L is located within the region formed by the one-dimensional photosensors 6a and 6b. On the other hand, in (b), the intersection point P
_L is located outside the area formed by the one-dimensional optical sensors 6a and 6b.

In FIG. 12, the mark image 3a formed by the image forming lens 4a and the mark image 3b formed by the image forming lens 4b are provided by the one-dimensional optical sensors 6a, 6b provided on the image forming surface 7. The modification of the three-dimensional position-and-orientation measuring device to detect is shown. The same parts as those in FIG. 1 are designated by the same reference numerals and reference numerals, and the duplicated description will be omitted.

Next, the detection accuracy of the intersection P _L of the straight lines L ₁ and L ₂ of the mark image 3a will be examined. For example, as shown in FIG. 13, in the two-dimensional coordinate system on the image plane 7a, the one-dimensional photosensors 6a and 6b have v _L = 1 and v _L = -1, and the intersections of the straight lines L _1L and L _2L are ( 0, w), the angle formed by the straight line L _{1L and the} one-dimensional optical sensor 6b is 45 degrees, and the angle formed by the straight lines L _1L and L _2L is 90 degrees, and the coordinates (h _L , v) of the intersection point P _{L at} this time are set.
Consider the detection accuracy of _L ).

Straight line L in the one-dimensional photosensors 6a and 6b
_When the detection errors of _1L and L _2L follow the normal distribution of mean zero and standard deviation σ _S , respectively, the coordinates (h _L , v _L ) of the intersection point P _L
Simulating the detection error of, their standard deviation σ
_h and σ _v are

[0052]

(Equation 6) Is approximated.

FIG. 14 shows this graph. It is shown that when w = 0, that is, the intersection P _L is located at the center of the one-dimensional optical sensors 6a and 6b, the detection accuracy is higher. Straight line L
_Although the absolute values of σ _h and σ _v are different even if the value of the inclination of _1L and the angle formed by the straight lines L _1L and L _2L are different, the detection accuracy increases as the intersection point P _L is located at the center of the one-dimensional optical sensors 6a and 6b. The characteristics of high are similar. In addition, the one-dimensional optical sensors 6a, 6
Even when b is not parallel, the detection accuracy is higher as the intersection P _L of the straight lines L _1L and L _2L is relatively inside. This was also confirmed by simulation.

Next, as shown in FIG. 15, in the two-dimensional coordinate system on the image plane 7a, the one-dimensional optical sensors 6a, 6b,
6c has v _L = 1, h _L = −1 and h _L = 1, a straight line L _1L ,
The intersection of L _2L is (0, w), and the straight line L _1L is the one-dimensional optical sensor 6
The angle with a is 45 degrees, and the angle between the straight lines L _1L and L _2L is 9
The detection accuracy of the coordinates (h _L , v _L ) of the intersection point P _L at 0 degree is verified.

[0055] 1-dimensional photosensor 6a, 6b, linear L _1L in 6c, the detection error of the position of the L _2L has an average zero, when following each normal distribution of standard deviation sigma _S, the intersection P _L of the coordinates (h _L, Simulate the detection error of v _L ).

FIG. 16 shows those standard deviations σ _h and σ _v . Also in this case, the detection accuracy is higher as the intersection P _{L of the} straight lines L _1L and L _2L is closer to the inside.

As described above, in order to improve the detection accuracy of the intersection point position of the straight line of the mark image as much as possible in both cases of the two-dimensional photosensors and the three-dimensional photosensors, FIGS. As shown, it is necessary to set the mark image and the one-dimensional photosensor so that the intersection of the straight lines of the mark image is inside the one-dimensional photosensor. Further, since the calculation of the three-dimensional position is performed by using the data of the position of the intersection of the left and right mark images, in order to improve the measurement accuracy, the intersection of the straight lines of the mark image is inside the area surrounded by the one-dimensional optical sensor. It is desirable to arrange the mark and the one-dimensional photosensor so that

FIG. 17 shows a third embodiment of the present invention.
A three-dimensional position-and-orientation measuring device is shown. This three-dimensional position-and-orientation measuring device is made of a light-transmitting material, and a target 3 on which a mark 3 having straight lines L ₁ and L ₂ having an intersection point P is formed. An object 1, light sources 21a and 21b for irradiating light to the object 1 to be measured from two directions, and a one-dimensional image input unit 19 in which one-dimensional optical sensors 6a and 6b are arranged in parallel on a light-receiving surface 20, and The calculation unit 9 calculates the position and orientation of the mark 3 based on the one-dimensional image data output from the two-dimensional photosensors 6a and 6b.

The mark 3 has a different transmittance from the object 1 to be measured, and it is sufficient that the mark position can be detected as a change in the light amount distribution on the one-dimensional photosensors 6a and 6b. For example, by applying a paint having a low transmittance. Has been formed. Light source 2
1a and 21b irradiate the measuring object 1 with the light emitted from the lamps 22a and 22b as parallel light by the light projecting lenses 23a and 23b. The one-dimensional image input unit 19 uses the light source 2
The mark images 3a and 3b formed by the light emitted from 1a and 21b are received by the light receiving surface 20. One-dimensional optical sensor 6a provided on the light receiving surface 20, 6b mark image 3a being projected, 3b of the straight line _{L 1L, L 2L, L 1R} , are arranged such L _2R crosses. The calculation unit 9 is a microcomputer or the like having an interface function with the one-dimensional image input unit. Further, the system block diagram of the three-dimensional position and orientation measuring apparatus according to the second embodiment is common to that in FIG. 12, and thus redundant description will be omitted.

Next, a method of calculating a three-dimensional position and orientation by the three-dimensional position and orientation measuring apparatus according to the second embodiment will be described.

FIG. 18 shows the positional relationship in the three-dimensional coordinate system between the measuring object 1 on which the mark 3 is formed and the light receiving surface 20 on which the one-dimensional optical sensors 6a and 6b are provided, and x
The y plane is defined on the light receiving surface 20. Light sources 21a, 2
The direction of the mark images 3a and 3b projected on the light receiving surface 20 based on the light emitted from 1b (neither is shown) is
Direction vector _{k (k x, k y,} k z), m (m x,
It is assumed that the direction is parallel to m _y , m _z ).

Next, the projected mark images 3a and 3b are directly
Line L_1L, L_2L, L_1R, L_2RSolve for the equation. One-dimensional light
As shown in FIG. 4, the sensors 6a and 6b have the mark image 3
Straight line L of a and 3b_1L, L_2L, L_1R, L_2RPosition intersecting with
The detection signal is output according to the light intensity of the. This one-dimensional optical sensor
Based on the detection signals of the sensors 6a and 6b, the primary of the light receiving surface 20
Linear equation of original optical sensor and straight line of mark images 3a, 3b
L_1L, L_2L, L_1R, L _2RPosition A where intersects with₁₁~ A_{twenty two}as well as
D₁₁~ D_{twenty two}And ask for A₁₁And A_{twenty one}From straight line L_1LRestore
A₁₂And A_{twenty two}From straight line L_2LRestore D₁₁And D_{twenty one}Straight from
L_1RRestore D₁₂And D_{twenty two}From straight line L_2RTo restore.

Next, the restored straight line L_1L, L_2L, L_1R,
L_2RTo the straight line L of the mark 3 on the target surface 2₁, L_Two
The position of the intersection point P (x, y, z) of is obtained. First, mark
Straight line L of image 3a_1L, L_2LThe intersection of_L(X_L, Y_L),
Straight line L of the mark image 3b_1R, L _2RThe intersection of_R(X_R, Y
_R), The direction vector k and the vector PP_LAre parallel
Therefore, the following relational expression k_z/ K_x= Z / (xx_L) --- (37) k_z/ K_y= Z / (y-y_L) --- (38) is obtained. Also, the direction vector m and the vector PP_RIs
Since they are parallel, the following relational expression m_z/ M_x= Z / (xx_R) --- (39) m_z/ M_y= Z / (y-y_R) --- (40) is obtained. Expressions (37) (38) (39) (40)
Solving the equations, x = (k_x・ M_z・ X_R-K_z・ M_x・ X_L) / (K_x・ M_z-K_z・ M_x) --- (41) y = (k_y・ M_z・ X_R-K_z・ M_y・ X_L) / (K_y・ M_z-K_z・ M_y) --- (42) z = k_z・ M_z(X_R-X_L) / (K_x・ M_z-K_z・ M_x) --- (43) or z = k_z・ M_z(X_R-X_L) / (K_y・ M_z-K_y・ M_x) --- (44) and the position of the intersection P is obtained.

Next, how to obtain the attitude of the mark 3 will be described below. Straight lines L _1L , L _2L , L _{1R of} the mark images 3a and 3b,
The direction vectors of L _2R are t _1L , t _2L , t _1R and t _{2R, respectively.}
Then, the normal vector q of the target surface 2, the direction vector r ₁ of the straight line L ₁ of the mark 3, and the direction vector r ₂ of the straight line L ₂ of the mark 3 are expressed by the following equation r ₁ = (t _1L × k) determined by _{× (t 1R × m) ---} (44) r 2 = (t 2L × k) × (t 2R × m) --- (45) q = r 1 × r 2 --- (46) To be

Furthermore, the normal vector is q (q _x , q _y , q
_z ) (where q _z > 0) and the direction vector r ₁ of the straight line L ₁ of the mark 3 is (r _1x , r _1y , r _1z ) (where r _1y > 0)
Assuming that the reference posture is the posture of the mark 3 when the normal vector q is parallel to the z-axis and the straight line L ₁ of the mark 3 is parallel to the y-axis, the inclination around each coordinate axis is the same as in the first embodiment. It can be obtained by the equations (21), (22) and (23) shown in the form.

FIG. 19 is a flow chart showing the arithmetic processing process in the arithmetic unit 9, and steps S ₁ , S ₂ , S
The position of the mark 3 can be obtained with ₃ , S ₄ , and S ₅ ,
The posture of the mark 3 can be obtained in steps S ₁ , S ₂ , S ₃ , S ₆ , S ₇ , and S ₈ .

In the above embodiment, the target surface on which the mark is formed is 1 even when the reflected light is used for the measuring object 1 or the transmitted light of the measuring object 1 is used.
It needs to be flat in the range detected by the two-dimensional photosensor. However, even if the target surface is not a perfect flat surface, for example, even if it is a gentle curved surface, it is possible to measure the position and orientation of the mark in three dimensions with accuracy according to the degree of the curved surface.

[0068]

As described above, according to the mark for three-dimensional position / orientation measurement, and the method and apparatus for three-dimensional position / orientation measurement of the present invention, two non-parallel lines provided on the target surface and providing one intersection point. Since the position and orientation in three dimensions are calculated based on at least two mark images detected by at least two one-dimensional optical sensors according to the mark including the minute, the simplification of the three-dimensional position and orientation measuring device is achieved. It is possible to reduce the cost as well as to reduce the cost.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a three-dimensional position and orientation measuring apparatus according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a relationship between an object coordinate system and a two-dimensional coordinate system on an image plane.

FIG. 3 is an explanatory diagram showing a mark image formed on an image plane.

FIG. 4 is an explanatory diagram showing the relationship between the position of the straight line of the one-dimensional photosensor and the mark image on the image plane of the first embodiment.

FIG. 5 is an explanatory diagram of calculation of a center of gravity according to the first embodiment.

FIG. 6 is a flowchart for calculating a three-dimensional position and orientation in the first embodiment.

FIG. 7 is an explanatory diagram showing a modified example of the mark according to the first embodiment.

FIG. 8 is an explanatory diagram showing a modification in which the contour line of the mark is used as a straight line in the first embodiment.

FIG. 9 is an explanatory diagram showing a positional relationship between a one-dimensional optical sensor and a straight line of a mark image on an image forming plane in a modification in which an edge of a measurement target is used as a mark.

10A and 10B are explanatory diagrams showing a modification of the arrangement of the one-dimensional photosensors on the image plane.

11A to 11D are explanatory views showing a modification of the mark reading mode.

FIG. 12 is an explanatory diagram showing a modified example of the image pickup unit.

FIG. 13 is an explanatory diagram showing a positional relationship between the intersections of straight lines of a mark image and two one-dimensional optical sensors.

14 is a graph of the position of the intersection of the straight lines of the mark image in FIG. 13 and the standard deviation of the intersection position detection error.

FIG. 15 is an explanatory diagram showing the positional relationship between the intersections of the straight lines of the mark image and the three one-dimensional photosensors.

16 is a graph of the position of the intersection of the straight lines of the mark image in FIG. 15 and the standard deviation of the intersection position detection error.

FIG. 17 is an explanatory diagram showing a three-dimensional position and orientation measuring apparatus according to the second embodiment of the present invention.

FIG. 18 is an explanatory diagram showing the positional relationship between the one-dimensional optical sensor on the light-receiving surface and the straight line of the mark image in the second embodiment.

FIG. 19 is a flowchart for calculating a three-dimensional position and orientation according to the second embodiment.

[Explanation of symbols]

1, measurement object 2, target surface 3, marks 3a, 3b, mark images 4a, 4b, imaging lenses 5a, 5b, imaging units 6a, 6b, 6c, 6d, one-dimensional photosensors 7a, 7b, imaging surface 9, arithmetic unit 10, synchronization signal generator 11a, 11b, 11c, 11d, drive circuit 12a, 12b, 12c, 12d, amplifier 13a, 13b, 13c, 13d, A / D converter 14, memory 15, memory control circuit 16, processor 17, display sections 18a, 18b, 18c, reading line 19, one-dimensional image input section 20, light receiving surfaces L ₁ , L ₂ , mark straight lines L ₁ ', L ₂ ', mark image straight line P, mark Intersection P ', intersection of mark images

Claims (17)

[Claims] 1. Includes two non-parallel line segments formed in a region of a given plane and providing one intersection, said one intersection being a reference point for position measurement, said two line segments being poses A three-dimensional position / orientation measurement mark, which is a measurement reference line. 2. The three-dimensional position-and-orientation measurement mark according to claim 1, wherein the intersection is provided within the predetermined area. 3. The three-dimensional position-and-orientation measurement mark according to claim 1, wherein the intersection is provided outside the predetermined area. 4. The three-dimensional position and orientation measurement according to claim 2, wherein the intersection is provided outside an area surrounded by the two line segments and at least two detection lines intersecting with the two line segments. Mark for. 5. The three-dimensional position and orientation measurement according to claim 2, wherein the intersection point is provided inside an area surrounded by the two line segments and at least two detection lines intersecting with the two line segments. Mark for. 6. A mark that includes two non-parallel line segments that provide one intersection and that is displaced in response to the displacement of the measurement target is formed on a first plane of the measurement target, and a second plane is formed. At least two one-dimensional photosensors are disposed on the second plane, the line segment images of the two line segments included in the mark are formed in two directions on the second plane, and the lengths of the at least two one-dimensional photosensors are increased. A light-reception signal representing a light-reception intensity distribution in a direction, and calculating positions of the two line-segment images on the at least two one-dimensional photosensors based on the light-reception signals. A three-dimensional position / orientation measuring method, characterized in that the position of the intersection point provided by two line segments included in the mark and the posture of the two line segments included in the mark are calculated based on the position of . 7. The three-dimensional position / orientation measuring method according to claim 6, wherein the mark is defined by defining an edge of the measuring object as at least one line segment of the two line segments. 8. The three-dimensional position / orientation according to claim 6, wherein the mark is formed by providing an opening for light transmission defined as at least one line segment of the two line segments in the measurement object. Measuring method. 9. The mark is defined as at least one line segment of the two line segments by applying, pasting, or coating a material having a reflectance different from that of the measurement object. The three-dimensional position and orientation measuring method described. 10. The mark is made to be light transmissive to the measurement object, and a material having a light transmittance different from that of the measurement object is applied to, adhered to, or coated on the measurement object. The three-dimensional position-and-orientation measuring method according to claim 6, which is defined as at least one line segment. 11. The at least two one-dimensional photosensors are respectively arranged in at least two on the third and fourth planes, and the line segment images of the two line segments included in the mark are arranged on the third and third planes. A three-dimensional position and orientation measuring method formed on each of the four planes. 12. A mark that includes two non-parallel line segments that are formed on a first plane of an object to be measured and that provide one intersection, and that is displaced in response to the displacement of the object to be measured. Image forming means for forming the line segment images of the two line segments included in the mark in two directions on a plane; and a length arranged on the second plane based on the line segment images of the two line segments. At least two one-dimensional photosensors that output a light-reception signal that represents a light-reception intensity distribution in a direction, and a first position that calculates the positions of the two line-segment images on the at least two one-dimensional photosensors based on the light-reception signals. The calculating means, the position of the intersection point provided by the two line segments included in the mark based on the positions on the at least two one-dimensional optical sensors, and the posture of the two line segments included in the mark. Second operator to calculate 3-dimensional position and orientation measuring apparatus characterized by comprising a. 13. The three-dimensional position-and-orientation measuring apparatus according to claim 12, wherein in the mark, at least one line segment of the two line segments is configured by an edge of the measurement target. 14. The three-dimensional position / orientation measurement according to claim 12, wherein the mark is formed by an opening for light transmission in which at least one line segment of the two line segments is formed in the measurement object. apparatus. 15. The mark is formed by applying, pasting, or covering at least one line segment of the two line segments on the measurement target with a material having a reflectance different from that of the measurement target. The three-dimensional position-and-orientation measuring apparatus according to claim 12. 16. The measurement target is made of a light transmissive material, and at least one line segment of the two line segments of the mark has a light transmission property different from that of the light transmissive material to the measurement target. The three-dimensional position-and-orientation measuring apparatus according to claim 12, wherein the three-dimensional position-and-orientation measuring apparatus is configured by applying, pasting, or coating a material having properties. 17. The image forming means has a structure for forming line segment images of the two line segments on a third and a fourth plane, respectively, and the at least two one-dimensional photosensors are provided on the third and fourth planes. The three-dimensional position-and-orientation measuring apparatus according to claim 12, having a configuration in which at least two are arranged on each of the fourth planes.