JP6029938B2 - Calibration method and three-dimensional processing apparatus - Google Patents

Description

  The present invention relates to a calibration method and a three-dimensional processing apparatus. More specifically, the present invention relates to a calibration method for measuring a three-dimensional shape by a light cutting method, and a tertiary method for measuring a three-dimensional shape using the calibration method. The present invention relates to an original processing apparatus.

  2. Description of the Related Art Conventionally, a three-dimensional processing apparatus is known that cuts a workpiece and shapes the workpiece into a predetermined shape.

  In order to perform cutting on a workpiece in such a three-dimensional processing apparatus, three-dimensional shape data indicating the shape of the workpiece after cutting is required.

As for the three-dimensional shape data, for example, a model having the same shape as the shape to be processed is used, and the three-dimensional shape of the model is measured by a three-dimensional shape measuring device to generate necessary three-dimensional shape data. It was.

  Here, as a technique for measuring the three-dimensional shape of a model in such a three-dimensional shape measuring apparatus, a technique for measuring the three-dimensional shape of a measurement object using light without contact is known.

  In general, there are a passive measurement method and an active measurement method as a technique for measuring the three-dimensional shape of an object to be measured in a non-contact manner using light.

  The passive measurement method is a method in which measurement is performed using ambient light without having a light projecting unit on the measurement device side, as represented by a stereo method.

  On the other hand, the active measurement method is a method of irradiating light from the light projecting means on the measurement device side toward the measurement object and measuring the reflected light.

  Among these active measurement methods, those using the principle of triangulation include the light section method, the spatial coding method, and the phase shift method.

  Specifically, for example, in the light cutting method, slit-like light is projected onto the measurement object, and the three-dimensional shape of the measurement object is measured.

  Here, the three-dimensional shape measuring apparatus using the light cutting method is configured to control the entire operation by a computer, and a camera for photographing the measurement object and the measurement object from a different direction from the camera. And a projector that irradiates slit-shaped light (hereinafter referred to as “slit light”), and the camera measures the object to which the slit light is projected from the projector.

  At this time, the shape of the slit light projected on the surface of the measurement object can be considered as the shape of the contour of the cross section of the measurement object on which the slit light is projected.

  For this reason, in this light cutting method, when measuring the three-dimensional shape of the measurement object, either the measurement object or the camera and the projector are moved at a predetermined interval, and the surface of the measurement object is subjected to slit light. Try to scan. At this time, the measurement object irradiated with the slit light is photographed at each predetermined interval, and the entire three-dimensional shape of the measurement object is measured based on the photographed image.

  Here, considering a point on the measurement object of the slit light, in a pinhole model that is easy to consider geometrically, the straight line connecting that point and the optical center of the camera is a point on the image plane of the camera. Pass through. That is, a certain point in the image determines a straight line extending from the camera to the measurement object, in other words, a line-of-sight equation.

  One slit light determines an equation of one plane extending from the projector to the measurement object.

  Since one point on the measurement object on which the slit light is projected exists on both the straight line (line of sight) and the plane, the object to be measured can be calculated by calculating the intersection of the straight line and the plane from these equations. The three-dimensional position of a point on the object can be calculated.

In the three-dimensional shape measuring apparatus using the light cutting method, the position where the slit light is projected is moved to perform such processing (that is, calculation of the three-dimensional position of each point on the slit light). By repeating, the three-dimensional shape is measured.

  By the way, in the three-dimensional shape measuring apparatus using the light cutting method as described above, the position of the slit light in the image of the measurement object imaged by the camera is matched with the position in the real space corresponding to the position. Need to be calibrated.

  That is, in the three-dimensional shape measuring apparatus using the above-described light cutting method, calibration for the camera (hereinafter referred to as “camera calibration”) is performed before actually measuring the three-dimensional shape of the measurement object. The external parameters and internal parameters of the camera are calculated, and the projector is calibrated (hereinafter referred to as “projector calibration”) to calculate the external parameters of the projector.

  For example, in the camera calibration, the Zhang method can be used, and the checker sheet (refer to FIG. 1) is used to move the checker sheet, so that at least six different directions (parallel movement and the same) Get video from (not including rotation).

  At this time, the upper left intersection of the checker sheet in the first image is the origin of the world coordinate system, the short side is the Y axis, the long is the X axis, and the cross product direction vector from the X axis to the Y axis is the Z axis. And

  Then, by specifying the length of one side of the square and the number of intersection points based on the captured image, the world coordinate origin and coordinate axes are set for the first image, and the camera center Where and where the camera is facing.

  Here, the length of one side of the square is the length of one side of the white and black squares representing the checker sheet pattern, and the number of intersections is the number of intersections of these white and black.

  Since the Zhang method described above is a known technique, a detailed description thereof will be omitted.

  Further, the position of the projector can be specified from the video shot by the camera calibrated camera.

  For example, after camera calibration, the image when the slit light is simply projected onto the table on which the subject is placed and the height on the table are projected onto an object with a known height From the image and the height of the object, an equation of a plane (one plane created when slit light is projected from the projector onto the subject) can be expressed in world coordinates.

Since various known techniques can be used for the specific method of calibration described above, detailed description thereof will be omitted.

  Here, when measuring a three-dimensional shape, as described above, by performing calibration, the camera is in which position and in what direction with respect to the coordinate system (world coordinate system) with an arbitrary place as the origin. And in which direction the image sensor is oriented (image coordinate system).

  And by the camera calibration as described above, where is the arbitrary origin, which position the camera is located in which direction (external parameter), and which direction the image sensor is oriented ( (Internal parameter).

In the three-dimensional shape measuring apparatus using the above-described light cutting method, either the “measurement object” or the “camera and projector” is moved at a predetermined interval, so that the world coordinate system, In addition to the three coordinate systems of the camera coordinate system and the image coordinate system, it is necessary to consider a machine coordinate system for movement. Such a machine coordinate system exists independently of the world coordinate system.

  In the prior art, when such a machine coordinate system is considered, for example, a process for estimating a movement vector by an optical flow disclosed in Non-Patent Document 1 is performed.

  That is, when the measurement object moves at a predetermined interval, the movement of the measurement object is recognized by the optical flow.

  Specifically, corresponding points are obtained from images before and after movement, and the moving direction and moving speed are analyzed as vectors from temporal and spatial changes of the corresponding points.

Then, using the acquired optical flow, the movement of the measurement object is treated as a motion parameter, and the machine coordinate system is taken into the world coordinate system and used as a dynamic change of the world coordinate system for measuring a three-dimensional shape.

  However, when using the optical flow as described above in camera calibration and projector calibration considering the machine coordinate system, the algorithm for detecting corresponding points from the image before movement and the image after movement is very complicated. It has become.

  As a result, the calibration method considering the machine coordinate system has been commanded as a problem that it is very difficult to create an algorithm for detecting corresponding points, and the amount of calculation is increased.

For this reason, the proposal of the calibration method which can be calibrated without using an optical flow in the apparatus which measures a three-dimensional shape was strongly desired.

  In the three-dimensional processing apparatus, for example, when processing a workpiece to be processed into a desired shape, three-dimensional shape data can be created by scanning a model of the desired shape. Then, it can be used for a wider range of applications as a three-dimensional processing apparatus.

  In such a case, it is necessary to perform the calibration as described above before creating the three-dimensional shape data in the three-dimensional processing apparatus.

  However, when the optical flow is used, there are the problems described above.

  For this reason, it is possible to calibrate without using an optical flow, and there has been a strong demand for a three-dimensional processing apparatus capable of creating a three-dimensional shape data by scanning a model.

“Basics of Robot Vision” by Koichiro Deguchi 2000 Corona

  The present invention has been made in view of the above-described demands of the prior art, and an object of the present invention is to propose a calibration method that can be calibrated without using an optical flow. It is what.

  In addition, an object of the present invention is to provide a three-dimensional processing apparatus that can perform calibration without using an optical flow and that can create a three-dimensional shape data by scanning a model. It is something to try.

  In order to achieve the above object, the calibration method according to the present invention fixes the camera and the projector and moves the measurement object (or moves the camera and the projector and fixes the measurement object). When measuring a three-dimensional shape by the cutting method, camera calibration is performed at at least two points on a straight line to which the measurement object can move, and external parameters of the camera and projector corresponding to the amount of movement of the measurement object are set. It is to be calculated.

  Note that the internal parameters of the camera may be acquired in advance or may be acquired at one of the two points described above.

Further, since the measurement object is placed on a moving means such as a table and moved by the movement of the moving means, “at least two points on a straight line on which the measurement object can move” is in other words. Then, “at least two points on a straight line on which the moving means can move”. Similarly, the “external parameters of the camera and projector according to the movement amount of the measurement object” is, in other words, “external parameters of the camera and projector according to the movement amount of the moving means”.

  Here, the moving means is actually configured to move on a straight line, but when viewed from a predetermined point on the moving means, it can be considered that the camera is moving (FIGS. 3A and 3B). 3 (a) and 3 (b), the world coordinate origin is shown as a predetermined point.

  Therefore, in the present invention, although the camera (projector) is actually fixed and the moving means is moving, it is considered that the moving means is fixed and the camera (projector) moves. is there.

  That is, the movement amount of the moving means is regarded as the relative movement amount of the camera (projector).

  When calculating the camera external parameters according to the movement amount of the moving means, the camera external parameters (the rotation matrix and the translation vector) at at least two points on the straight line that the moving means can move are calculated. Then, based on the calculated external parameters at at least two points, the external parameters of the camera for each moving pitch of the moving means are obtained in proportion to the moving pitch of the moving means.

  Specifically, a calculation formula for calculating a camera external parameter (hereinafter referred to as “camera dynamic external parameter” as appropriate) according to the moving amount of the moving means is created, and the created calculation is performed. A dynamic external parameter of the camera (a translation vector indicating the camera position and a rotation matrix indicating the camera direction) is calculated from the equation.

Furthermore, from the calculated dynamic external parameters of the camera, the external parameters of the projector corresponding to the movement amount of the moving means (hereinafter referred to as “dynamic external parameters of the projector” as appropriate) are calculated. It is a thing.

  A method for calculating the dynamic external parameters of the camera and the dynamic external parameters of the projector will be described below.

  Here, in the following description, it is assumed that the moving means moves in the front-rear direction, and “the position of the most forward moving means where the checker seat (described later) can be photographed by the camera” is referred to as “front end”. , “The position of the most rearward moving means where the checker sheet (not shown) can be photographed by the camera” is referred to as “rear end”.

  Then, the moving means moves in a predetermined pitch width unit in the front-rear direction, the external parameters of the camera when the moving means is located at the front end are the translation vector “Tf”, the rotation matrix “Rf”, and the moving means Assume that the external parameters of the camera at the end are a translation vector “Tb” and a rotation matrix “Rb”.

Further, the total movement amount from the front end to the rear end of the moving means is “S”, the predetermined pitch width which is the minimum unit in which the moving means moves is “P”, and the movement count from the front end of the moving means is “C”. And When the moving means moves, the moving amount of the moving means is counted in a predetermined pitch width unit with the front end as a base point, and the movement count from the front end of the moving means is this count number. .

First, a method for calculating dynamic external parameters of the camera will be described. That is, a method for calculating a translation vector and a rotation matrix according to the amount of movement of the moving means will be described.

A translation vector “T” corresponding to the amount of movement of the moving means when the moving means moves from the front end to the rear end is expressed by the following equation (1).
T = Tf + (Tb−Tf) / S × P × C (1)

  Also, if the moving means is moving only in a straight line, it is ideally not necessary to consider the rotation matrix, but in reality it is necessary to consider changes in the rotation matrix.

Here, as with the translation vector, when the moving means moves from the front end to the rear end, the rotation matrix becomes
Rf → Rb
To change. This change is a rotation of the rotation matrix.

If the matrix that rotates the rotation matrix is “n”,
Rf × n = Rb
It becomes.

Therefore,
n = Rf ⁻¹ × Rb
It becomes. Rf ⁻¹ is an inverse matrix of Rf. Since Rf itself is a rotation matrix and an orthonormal matrix, an inverse matrix exists.

  Next, similarly to the translation vector, a change of “n” corresponding to the moving amount of the moving means is considered.

  Since “n” is a rotation matrix, the rotation amount (angle) corresponding to the movement amount of the moving means (according to the movement count from the front end of the moving means) cannot be directly acquired.

  Therefore, it is necessary to decompose “n” into the rotation axis and the rotation amount (angle), and the Rodriguez rotation formula is used. In addition, since it is a well-known technique about the rotation formula of Rodrigues, conversion to a rotating shaft, and rotation amount, the detailed description is abbreviate | omitted.

That is, “n” is Rodriguez's rotation formula,
n = θj
It becomes. Note that “θ” is a rotation amount, and “j” is a rotation axis (unit direction vector).

As a result, when the rotation amount according to the movement amount of the moving means is “θ ′”,
θ ′ = θ / S × P × C
It becomes.

  Therefore, the rotation vector corresponding to the movement amount of the moving means expressed by the Rodriguez rotation formula is “θ′j”.

  The rotation matrix “n ′” corresponding to the amount of movement of the moving means can be acquired by performing the inverse transformation of Rodrigues and returning this “θ′j” to the rotation matrix.

Thereby, the rotation matrix “Rb ′” corresponding to the movement amount of the moving means is expressed by the following equation (2).
Rb ′ = Rf × n ′ (2)

In this way, the dynamic external parameters of the camera (the translation vector “T” and the rotation matrix “Rb ′” corresponding to the amount of movement of the moving means are derived from the above equations (1) and (2) according to the movement count. )).

  Next, a method for calculating dynamic external parameters of the projector will be described.

  First, coefficients a, b, c, d (that is, external parameters of the projector) of a plane equation “ax + by + cz + d = 0” indicating a light plane emerging from the projector when the moving unit is located at the front end are calculated. To do.

  Since a known technique is used for the calculation method of the external parameters of the projector, detailed description thereof will be omitted.

Further, the relative positional relationship between the optical plane represented by the calculated plane equation and the camera does not change even when the moving means moves. That is, if the equation of the plane is expressed in the world coordinate system, it changes due to the movement of the moving means, but if the equation of the plane is expressed in the camera coordinate system, it does not change even if the moving means moves. .

That is, in order to obtain a dynamic external parameter of the projector, first, an equation of a plane indicating the light plane is expressed in the world coordinate system. That is, it is expressed as ax + by + cz + d = 0.

Next, arbitrary three points P _0W , P _1W , P _2W on “ax + by + cz + d = 0” (the arbitrary three points P _0W , P _1W , P _2W are, of course, world coordinates),
P _0W (X _0W , Y _0W , Z _0W )
P _1W (X _1W , Y _1W , Z _1W )
P _2W (X _2W , Y _2W , Z _2W )
And

Then, the points P _0W , P _1W , and P _2W are respectively expressed in the camera coordinate system using the external parameters (rotation matrix: Rf, translation vector: Tf) of the camera when the moving means is located at the front end.

That is, if the point corresponding to the point P _0W in the camera coordinate system is the point P _0C ,
P _0C = Rf × P _0W + Tf
To obtain P _0C (X _0C , Y _0C , Z _0C ).

Further, if a point corresponding to the point P _1W in the camera coordinate system is a point P _1C ,
P _1C = Rf × P _1W + Tf
To obtain P _1C (X _1C , Y _1C , Z _1C ).

Furthermore, if a point corresponding to the point P _2W in the camera coordinate system is a point P _2C ,
P _2C = Rf × P _2W + Tf
To obtain P _2C (X _2C , Y _2C , Z _2C ).

Thereafter, the points P _0C , P _1C , and P _2C are expressed in a dynamic world coordinate system using dynamic external parameters of the camera.

That is, if a point expressing the point P _0C in the dynamic world coordinate system is a point P ′ _0W ,
P ′ _0W = inv (Rb ′) × P _0C −inv (Rb ′) × T
To obtain P ′ _0W (X ′ _0W , Y ′ _0W , Z ′ _0W ).

Further, if a point expressing the point P _1C in the dynamic world coordinate system is a point P ′ _1W ,
P ′ _1W = inv (Rb ′) × P _1C −inv (Rb ′) × T
To obtain P ′ _1W (X ′ _1W , Y ′ _1W , Z ′ _1W ).

Furthermore, if a point expressing the point P _2C in the dynamic world coordinate system is a point P ′ _2W ,
P ′ _2W = inv (Rb ′) × P _2C −inv (Rb ′) × T
To obtain P ′ _2W (X ′ _2W , Y ′ _2W , Z ′ _2W ).

  Note that inv (Rb ′) is an inverse matrix of Rb ′.

A plane equation “a′x + b′y + c′z + d ′ = 0” is newly obtained from the three points P ′ _0W , P ′ _1W and P ′ _2W calculated in this way.

  The coefficients “a ′, b ′, c ′, d ′” thus determined are dynamic external parameters of the projector.

Therefore, the dynamic external parameter of the projector changes according to the dynamic external parameter of the camera that changes according to the movement count number.

Geometrically, “ax + by + cz + d = 0” (world coordinate system representation) is directly converted into “a′x + b′y + c′z + d ′ = 0” by dynamic external parameters “T” and “Rb ′” of the camera. You can also

Here, in the above description, the case where the camera calibration is performed at two points (front end and rear end) on the straight line to which the measurement object can move has been described. However, at least three points on the straight line to which the measurement object can move. When performing calibration at this point, the same processing as that when performing calibration at the two points (front end and rear end) on the straight line where the measurement object can move between two adjacent points is performed. Thus, the dynamic external parameters of the camera and projector may be calculated.

  After calculating the camera internal parameters and dynamic external parameters and the projector dynamic external parameters as described above, the calculated camera internal parameters and dynamic external parameters and projector dynamic external parameters Measure 3D shape using.

  That is, based on the dynamic external parameters of the camera and the dynamic external parameters of the projector according to the movement amount (that is, the movement count number) of the video imaged by the camera, the measurement formed by the slit light in the video image By measuring the three-dimensional shape of the object and repeating these processes, the entire three-dimensional shape of the measurement object is measured.

As described above, in the calibration method according to the present invention, a camera corresponding to the amount of movement of the measurement object (the measurement object placed on the table) can be easily obtained without using a complicated algorithm. Further, external parameters of the projector can be acquired, and calibration can be easily performed.

  In addition, the three-dimensional processing apparatus according to the present invention performs calibration using the calibration method described above, and then scans a model having a desired shape to measure the three-dimensional shape of the model. From the measurement results, three-dimensional shape data of a desired shape is created using dedicated software or the like.

Thereby, in the three-dimensional processing apparatus according to the present invention, three-dimensional shape data can be easily created, and the workpiece can be processed into a desired shape.

  That is, the calibration method according to the present invention includes a projector that measures the three-dimensional shape of an object to be measured by a light cutting method and projects slit light, and a camera that photographs slit light projected from the projector. Is fixedly arranged, and in the calibration method in the three-dimensional shape measuring apparatus in which the measuring object is moved by the moving means, at least two images can be taken by the camera and the moving means can be moved. The external parameter of the camera is calculated at the location, and the external parameter of the camera based on the moving amount of the moving means is obtained in proportion to the minimum moving unit of the moving means from the calculated external parameter of the camera. The projector external parameters are extracted from the camera external parameters based on the amount of movement. It is obtained by way.

  Further, in the calibration method according to the present invention, in the above-described invention, at least two positions where the moving means can move are front end portions which are the frontmost side capable of photographing the checker sheet placed on the moving means by the camera. And a rear end that is the rearmost side that can photograph the checker sheet placed on the moving means by the camera, and the camera is photographed by positioning the camera at the front end. Is positioned in the rear end portion, and the checker sheet is photographed from at least six different directions, the camera is again positioned in the front end portion, and the checker sheet is in a direction not yet photographed, and By shooting from at least 5 different directions, at least 6 Acquired images of checker sheets taken from different directions, acquired images of checker sheets taken from at least six different directions at the rear end, and taken from at least six different directions at the front end. Based on the image of the checker sheet, external parameters of the camera at the front end are obtained, and at the rear end, based on the images of the checker sheet taken from at least six different directions, The parameters are obtained.

  Further, the three-dimensional processing apparatus according to the present invention is a three-dimensional processing apparatus that performs three-dimensional processing on a workpiece based on three-dimensional shape data, and a measurement object formed in the workpiece or a desired shape. A moving means capable of placing an object and changing an inclination angle in at least six different directions, a projector that projects slit light on the moving means, and slit light projected from the projector A camera that controls the movement and tilt angle of the moving means, a control means that controls the timing of slit light projection of the projector and the timing of shooting of the camera, and the calibration according to the present invention described above. In addition to performing calibration by the method, the three-dimensional shape of the measurement object is measured by the light cutting method. It is obtained so as to have a three-dimensional shape measuring means for creating a three-dimensional shape data of the measuring object.

  In the three-dimensional processing apparatus according to the present invention, in the above-described invention, the camera and the projector are attached when the calibration and the three-dimensional shape data of the measurement object are created, It is removed when performing three-dimensional processing.

  Since the present invention is configured as described above, it has an excellent effect that calibration can be performed without using an optical flow.

  Further, since the present invention is configured as described above, it has an excellent effect that simple calibration can be performed and a model can be scanned to create three-dimensional shape data. Is.

FIG. 1 is an explanatory diagram showing a checker sheet used in the Zhang method. FIG. 2 is a schematic perspective view illustrating the main part of the three-dimensional processing apparatus according to the present invention. FIG. 3A is an explanatory diagram when the table is moved while the camera and the projector are fixed, and FIG. 3B is an explanatory diagram when the camera and the projector are moved while the table is fixed. FIG. FIG. 4 is a flowchart showing the detailed processing contents of the camera calibration processing.

Hereinafter, an example of an embodiment of a calibration method and a three-dimensional processing apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

  Here, FIG. 2 shows a schematic configuration explanation showing the main part of the three-dimensional processing apparatus according to the present invention.

  A three-dimensional processing apparatus 10 shown in FIG. 2 is a three-dimensional processing apparatus capable of measuring a three-dimensional shape and creating three-dimensional shape data. In FIG. 2, only the main part is shown. A structure such as a housing is provided so as to surround the main part shown in FIG.

Further, when creating the three-dimensional shape data, the three-dimensional processing apparatus 10 places a model on a table 14 to be described later, and moves the table 14, that is, moves the model that is a measurement object. By this, the three-dimensional shape of the measurement object is acquired.

  The three-dimensional processing apparatus 10 is mounted with a workpiece 100 to be processed and a measurement target 200 to be a model for creating three-dimensional shape data, and in the X-axis direction in the XYZ orthogonal coordinate system. A moving table 14 is disposed on the upper surface 12 a of the base member 12.

  Further, in the base member 12, a standing member 16 is erected at the left side end portion of the upper surface 12a, and is opposed to the standing member 16 at the right side end portion of the upper surface 12a. A standing member 18 is erected.

  In the standing members 16 and 18, a guide rail 20 extends in the Y-axis direction so as to connect the standing members 16 and 18, and the guide rail 20 is used for processing the workpiece 100. A head portion 24 that supports the processing tool 22 is slidably disposed.

  Further, in the standing members 16 and 18, a plate-like member 26 is provided so as to connect the upper end portion 16 a of the standing member 16 and the upper end portion 18 a of the standing member 18.

  On the upper surface 26 a of the plate-like member 26, a projector 28 that projects slit light onto the measurement object 200 placed on the table 14 is disposed, and the measurement placed on the table 14. A camera 30 for photographing the object 200 is provided. At this time, the camera 30 is disposed such that the angle at which the measurement object 200 is photographed is different from the angle at which the projector 28 projects slit light onto the measurement object 200.

Note that the entire operation of the three-dimensional processing apparatus 10 is controlled by a microcomputer (not shown).

  More specifically, guide grooves 32a and 32b extend in the X-axis direction on the upper surface 12a of the base member 12, and the table 14 is moved along the guide grooves 32a and 32b by a moving mechanism (not shown). It moves in the axial direction.

  The table 14 is inclined in, for example, six different directions by a moving mechanism (not shown). Each of the six different directions includes a horizontal state when the workpiece 100 is placed and processed, and does not include parallel movement and the same rotation.

  Further, this moving mechanism moves at a predetermined pitch width. When the table 14 moves, how many times the table 14 moves at a predetermined pitch width from the front end portion (described later) of the table 14 as a base point. The counted value is output to a microcomputer (not shown) and stored.

In addition, about the movement mechanism (not shown) in such a table 14, since a conventionally well-known technique is used, the detailed description shall be abbreviate | omitted.

The standing member 16 is provided with a drive member 34 that is driven based on control of a microcomputer (not shown), and the head member 24 moves in the Y-axis direction along the guide rail 20 by the drive of the drive member 34. .

  The head portion 24 is disposed on the moving member 24a slidably disposed on the guide rail 20, the moving member 24b provided on the front surface of the moving member 24a and movable in the Z-axis direction, and the moving member 24b. And a spindle unit 24c that supports the machining tool 22.

  As a result, the moving member 24 a can move in the Y-axis direction by driving the driving member 34 provided on the standing member 16.

  The moving member 24b is slidably disposed on a pair of guide rails 24ba extending in the Z-axis direction on the front side of the moving member 24b, and is driven by a driving means (not shown). It is possible to move in the direction.

Further, the spindle unit 24c supports the machining tool 22, and can rotate the machining tool 22 by a driving means (not shown).

  The projector 28 includes a light emitting diode (not shown) and a filter (not shown) in which slits of a predetermined size are formed.

  Then, the projector 28 converts the light from the light emitting diode (not shown) into slit light through a filter (not shown), and this slit light is applied to the measurement object 200 placed on the table 14. It is designed to flood.

The projector 28 is configured to control all operations such as the timing of light projection by a microcomputer (not shown).

  The camera 30 is arranged so that the surface of the measuring object 200 placed on the table 14 can be photographed from a direction different from the light projecting direction of the projector 28.

And the image | video image | photographed with the camera 30 is digitized and it is made to take in into a microcomputer (not shown).

  In the above configuration, when processing the workpiece 100 into a desired three-dimensional shape in the three-dimensional processing apparatus 10, the three-dimensional shape data necessary for processing the workpiece 100 is created and created. The workpiece 100 is processed using the three-dimensional shape data.

  First, creation of three-dimensional shape data necessary when processing the workpiece 100 will be described.

  In order to create such three-dimensional shape data, the camera 30 and the projector 28 are calibrated.

  To calibrate the camera 30 and the projector 28, first, a checker sheet 110 (see FIG. 3) on which a checkered pattern is drawn is fixed on the table 14. The checker sheet 110 is configured to be detachable from the table 14 with, for example, a tape so that the checker sheet 110 does not easily move on the table 14 when placed on the table 14. Has been made.

  Thereafter, the table 14 on which the checker sheet 110 is placed is moved, and camera calibration is performed in at least two places in the range in which the checker sheet 110 can be photographed by the camera 30.

Hereinafter, the camera calibration process will be described with reference to FIG. FIG. 4 shows a flowchart showing the processing procedure of the camera calibration process.

  First, the table 14 is moved to the foremost side where the checker seat 110 can be photographed by the camera 30 (step S402). At this time, the table 14 is in a horizontal state.

  That is, in the process of step S402, when the operator operates an operator (not shown) to move the table 14 via a microcomputer (not shown), the checker sheet 110 can be photographed most by the camera 30. Try to locate it on the front side.

  At this time, the microcomputer (not shown) stores the most forward position where the checker seat 110 can be photographed by the camera 30.

  In the following description, “the position of the table 14 when the checker seat 110 is located on the most front side that can be photographed by the camera 30” is referred to as “front end”.

Further, in the following description, the fact that the checker sheet 110 can be photographed by the camera 30 means that the entire checker sheet 110 can be photographed by the camera 30. The determination as to whether or not the entire checker sheet 110 can be photographed by the camera 30 is performed by, for example, displaying an image photographed by the camera 30 via an external display via a microcomputer (not shown). The information is displayed on a device or the like, and the operator judges it visually.

Then, with the table 14 positioned at the front end, the checker sheet 110 is photographed by the camera 30 (step S404). In addition, the image | video image | photographed in this way is memorize | stored in a microcomputer (not shown).

  Next, the table 14 is moved to the rearmost side where the checker sheet 110 can be photographed by the camera 30 (step S406). At this time, the table 14 is in a horizontal state.

  In the following description, “the position of the table 14 when the checker sheet 110 is located at the rearmost side where the camera 30 can shoot” is referred to as a “rear end”.

That is, in the process of step S406, when the operator operates an operator (not shown), the table 14 is moved to the rear end via a microcomputer (not shown).

  Then, with the table 14 positioned at the rear end, the checker sheet 110 is photographed by the camera 30 (step S408). In addition, the image | video image | photographed in this way is memorize | stored in a microcomputer (not shown).

That is, in the process of step S408, the horizontal checker sheet is photographed.

  Thereafter, with the table 14 positioned at the rear end, the table 14 is set to five states having different inclination angles, and the checker sheet 110 is photographed in each of the five states (step S410). The video shot in this way is stored in a microcomputer (not shown) in association with the video shot in the process of step S408.

  That is, in the process of step S410, the table 14 is set to five states having different inclination angles so that the table 14 is not in the parallel movement or the same rotation state with the table 14 positioned at the rear end portion. Each checker sheet 110 is photographed.

  Specifically, in the process of step S410, the table 14 is inclined from the horizontal state to the first state, and the checker sheet 110 is photographed in the first state. Further, the table 14 is inclined from the first state to the second state, and the checker sheet 110 is photographed in the second state. Further, the table 14 is inclined from the second state to the third state, and the checker sheet 110 is photographed in the third state. Further, the table 14 is inclined from the third state to the fourth state, and the checker sheet 110 is photographed in the fourth state. Further, the table 14 is inclined from the fourth state to the fifth state, and the checker sheet 110 is photographed in the fifth state.

  At this time, the table 14 is located at the rear end, and the first to fifth states are not in a horizontal state and are not at an inclination angle in the same direction. Further, the inclination angle of the table 14 for achieving the first to fifth states may be arbitrarily determined by the operator, or stored in advance in a microcomputer (not shown). May be.

By the processing in step S410 and the processing in step S408, images of six checker sheets 110 having different shooting directions when the table 14 is located at the rear end are acquired.

  Next, the table 14 is moved to the front end portion moved in step S402 (step S412).

That is, in the process of step S412, the table 14 is moved to the front end portion stored in the microcomputer under the control of the microcomputer (not shown).

  Then, with the table 14 positioned at the front end, the table 14 is set to five states having different inclination angles, and the checker sheet 110 is photographed in each of the five states (step S414). The video shot in this way is stored in a microcomputer (not shown) in association with the video shot in the process of step S404.

  That is, in the process of step S414, the table 14 is set to five states having different inclination angles so that the table 14 is not moved in parallel or rotated in the state where the table 14 is located at the front end portion. The checker sheet 110 is photographed.

  Specifically, in the process of step S414, the table 14 is inclined from the horizontal state to the sixth state, and the checker sheet 110 is photographed in the sixth state. Further, the table 14 is inclined from the sixth state to the seventh state, and the checker sheet 110 is photographed in the seventh state. Further, the table 14 is inclined from the seventh state to the eighth state, and the checker sheet 110 is photographed in the eighth state. Further, the table 14 is tilted from the eighth state to the ninth state, and the checker sheet 110 is photographed in the ninth state. Further, the table 14 is inclined from the ninth state to the tenth state, and the checker sheet 110 is photographed in the tenth state.

  At this time, the table 14 is located at the front end, and the sixth to tenth states are not in a horizontal state and are not at an inclination angle in the same direction. The sixth to tenth states may be arbitrarily determined by the operator, or may be stored in advance in a microcomputer (not shown). When the operator arbitrarily determines, the first to fifth states and the sixth to tenth states are stored in the microcomputer (not shown) in the process of step S410. The state may be set to the same inclination.

Through the processing in step S414 and the processing in step S404, images of six checker sheets 110 having different shooting directions when the table 14 is positioned at the front end are acquired.

  Thereafter, in a microcomputer (not shown), camera calibration is performed when the table 14 is located at the front end from the video imaged in step S404 and the video imaged in step S414 (step 414). S416).

  That is, the external parameters and internal parameters of the camera when the table 14 is located at the front end are acquired using six images stored in a microcomputer (not shown).

In addition, since it is a well-known technique about the method to acquire the external parameter and internal parameter of a camera, the detailed description is abbreviate | omitted.

  When the camera calibration when the table 14 is located at the front end is completed, the microcomputer (not shown) then uses the video imaged in step S408 and the video imaged in step S410. Then, camera calibration is performed when the table 14 is positioned at the rear end (step S418).

That is, the external parameters of the camera when the table 14 is located at the front end are acquired using six images stored in a microcomputer (not shown).

  Next, using the camera external parameters acquired in step S416 and the camera external parameters acquired in step S418, a calculation formula for calculating dynamic camera external parameters is acquired (step S420), and the movement count number is acquired. Each time a dynamic external parameter of the camera is acquired (step S422).

  That is, in the process of step S420, the expressions (1) and (2) are acquired as described above.

When the process of step S422 ends, the camera calibration process ends.

  When the camera calibration process ends, the dynamic external parameters of the projector are acquired based on the acquired dynamic external parameters of the camera.

Since the method for acquiring the dynamic external parameters of the projector has already been described above, the details thereof will be omitted.

  When calibration between the camera 30 and the projector 28 is completed, next, three-dimensional shape data is created.

  In the creation of the three-dimensional shape data, first, a measurement object 200 as a three-dimensional shape model to be created is prepared, and the measurement object 200 is placed on the table 14 from which the checker sheet 110 is removed.

Then, the table 14 is moved to a predetermined position, and the table 14 is moved from the predetermined position to the rear end portion with a predetermined pitch width. At this time, every time the table 14 moves with a predetermined pitch width, the measurement object 200 is placed, and the table 14 on which the slit light is projected by the projector 28 is photographed by the camera 30.

  In this way, the primary data of the three-dimensional shape of the measuring object 200 is acquired from the video captured at every predetermined pitch width while moving the table 14.

  The acquired primary data of the three-dimensional shape is output to, for example, a personal computer (not shown) connected to a microcomputer (not shown), and the secondary data of the three-dimensional shape is created on the personal computer. The secondary data of the three-dimensional shape is created from the primary data by using dedicated software or the like.

The secondary data created by a personal computer (not shown) is output to a microcomputer (not shown) and stored as three-dimensional shape data in the microcomputer.

  Then, secondary data of the three-dimensional shape data created by a personal computer (not shown) is converted into cutting data. Thereafter, the cutting data is output to a microcomputer (not shown) and stored as cutting data in the microcomputer.

In addition, about the process which converts 3D shape data into cutting data, since various well-known techniques are used, the detailed description is abbreviate | omitted.

  When the cutting data is created from the three-dimensional data, the operator places the workpiece 100 on the table 14 and supports the machining tool 22 on the spindle 24 c of the head portion 24.

Thereafter, when the operator gives an instruction to start machining via an operator (not shown), the table 14 is moved in the X-axis direction based on the created cutting data under the control of a microcomputer (not shown). Then, the head portion 24 is moved in the Y-axis direction, and the moving member 24b is further moved in the Z-axis direction, and the workpiece 100 is subjected to three-dimensional machining by the machining tool 22.

  As described above, in the calibration method according to the present invention, in the three-dimensional processing apparatus 10, the measurement target 200 is fixed when the camera 30 and the projector 28 are actually fixed and the measurement target 200 moves. The camera 30 and the projector 28 are considered to move, and the camera calibration is performed at least at two places where the table 14 as the moving means on which the measurement object 200 is placed can move.

  At this time, the location where the camera calibration is performed is a location where the checker sheet 110 can be photographed by the camera 30.

  Then, at the front end portion and the rear end portion of the table 14 for performing camera calibration, first, photographing is performed when the checker sheet 110 is in the horizontal state at the front end portion, and then, when the checker sheet is in the horizontal state at the rear end portion. 6 states (each having a different inclination angle) were photographed, and thereafter, five states of the checker sheet 110 (each having a different inclination angle) were photographed at the front end. .

  From the camera external parameters thus calculated, the camera's dynamic external parameters are calculated in proportion to each predetermined pitch, which is the minimum movement unit of the table 14.

  As a result, in the calibration method according to the present invention, the calibration can be easily performed.

In the three-dimensional processing apparatus 10 according to the present invention, three-dimensional shape data can be easily created, and three-dimensional processing of various shapes can be performed.

  The embodiment described above may be modified as shown in the following (1) to (8).

  (1) In the above-described embodiment, the projector 28 is configured to include a light emitting diode and a filter in which a slit is formed. However, the present invention is not limited to this, For example, a line laser may be used, and as the projector 28, various known techniques that can project slit light may be used.

  (2) In the above-described embodiment, the camera 30 and the projector 28 are provided above the head unit 24. For example, the head unit 24, the camera 30, and the projector 28 are separated. Also good.

  Specifically, the plate member 26 provided with the camera 30 and the projector 28 is configured to be removable, and is disposed on the upper end portions 16a and 18a of the standing members 16 and 18 only when three-dimensional shape data is created. It is good also as such a structure.

  Alternatively, the standing members 16 and 18 provided with the head member 24 can be tilted backward, and when the three-dimensional shape data is created, the standing members 16 and 18 are tilted. Tilt backwards to create a space above the table 14. Thereafter, the base member 12 is provided with a leg portion that can be fixed, the fixing member provided with the camera 30 and the projector 28 is fixed on the base member 12, and the camera 30 and the projector 28 provided on the fixing member are used. Calibration and creation of three-dimensional shape data may be performed.

  (3) In the above-described embodiment, at least two points on the straight line to which the moving means can be moved are the front end portion and the rear end portion of the table 14 as the locations where the camera calibration is performed. Of course, any two or more points may be selected as camera calibration locations as long as the camera 30 can be photographed and the table 14 is movable.

  (4) In the above-described embodiment, the camera internal parameters are acquired in the process of step S416. However, the camera internal parameters may be acquired in the process of step S418.

  (5) In the above-described embodiment, the checker sheet 110 is photographed from six different directions. However, the present invention is not limited to this. Of course, the checker sheet 110 is photographed from seven or more different directions. The sheet 110 may be photographed.

  (6) In the above-described embodiment, in the camera calibration process, captured video data and the like are stored in a microcomputer (not shown), and the external parameters, internal parameters, and dynamics of the camera are stored in the microcomputer. Although external parameters, projector external parameters, dynamic external parameters, and the like are acquired, the present invention is not limited to this.

  That is, a personal computer is connected to the three-dimensional processing apparatus 10 and the captured video data and the like are stored in the personal computer. In the personal computer, the camera external parameters, internal parameters, dynamic external parameters, and projector externals are stored. You may make it acquire a parameter, a dynamic external parameter, etc.

  (7) In the above-described embodiment, the table 14 is set in the horizontal state in the processing in step S402 and the processing in step S406. However, the present invention is not limited to this, and the table 14 is not in the horizontal state. A tilted state tilted in an arbitrary direction may be used.

  In this case, in the process of step S410, none of the first to fifth states is the tilted state in step S402, and is not in the tilt angle in the same direction.

  Further, in the process of step S414, the sixth to tenth states are not in the inclined state in the process of step S406, and are not in an inclination angle in the same direction.

  (8) You may make it combine suitably the embodiment shown above and the modification shown in said (1) thru | or (7).

  The present invention is suitable for use as a calibration method for processing a workpiece into a three-dimensional shape.

  DESCRIPTION OF SYMBOLS 10 Three-dimensional processing apparatus, 12 Base member, 14 Table, 16, 18 Standing member, 20 Guide rail, 22 Processing tool, 24 Head part, 26 Plate-shaped member, 28 Projector, 30 Camera, 100 Workpiece, 110 Checker sheet, 200 object to be measured

Claims (4)

A projector that measures the three-dimensional shape of an object to be measured by a light cutting method, and that projects slit light, and a camera that photographs slit light projected from the projector are fixedly disposed, and moving means In the calibration method in the three-dimensional shape measuring apparatus adapted to move the measurement object by
The external parameters of the camera are calculated in at least two places where the photographing by the camera is possible and the moving means is movable,
From the calculated external parameter of the camera, in proportion to the minimum movement unit of the moving means, to acquire the external parameter of the camera based on the moving amount of the moving means,
A calibration method, wherein external parameters of the projector are acquired from external parameters of the camera based on the acquired movement amount. The calibration method according to claim 1,
At least two places where the moving means can move are a front end portion which is the foremost side capable of photographing a checker sheet placed on the moving means by the camera, and the checker placed on the moving means by the camera. And the rear end, which is the rearmost side capable of photographing the seat,
The camera is positioned at the front end to capture the checker sheet, the camera is positioned at the rear end to capture the checker sheet from at least six different directions, and the camera is again positioned at the front end. By capturing the checker sheet in a direction that has not yet been photographed and photographed from at least five different directions, images of the checker sheet photographed from at least six different directions at the front end are obtained. And acquiring images of checker sheets taken from at least six different directions at the rear end,
Based on images of checker sheets taken from at least six different directions at the front end, external parameters of the camera at the front end are obtained, and checker sheets taken from at least six different directions at the rear end. A calibration method characterized in that an external parameter of the camera at the rear end portion is obtained based on an image. In the three-dimensional processing device that performs three-dimensional processing on the workpiece based on the three-dimensional shape data,
A moving means for placing the workpiece and the measurement object formed in a desired shape and capable of changing the inclination angle in at least six different directions,
A projector that projects slit light on the moving means;
A camera for photographing the slit light projected from the projector;
Control means for controlling the movement and tilt angle of the moving means, and the timing for projecting the slit light of the projector and the timing for photographing the camera;
A calibration is performed by the calibration method according to any one of claims 1 and 2, and a three-dimensional shape of the measurement object is measured by a light cutting method to measure the three-dimensional shape of the measurement object. A three-dimensional processing apparatus comprising: three-dimensional shape measuring means for creating data. In the three-dimensional processing apparatus according to claim 3,
The camera and the projector are attached when calibration and three-dimensional shape data of the measurement object are created, and are removed when performing three-dimensional machining on the workpiece. Original processing equipment.

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