JP4766839B2 - Measuring method, measuring system and program - Google Patents

Description

  The present invention relates to a measurement technique for measuring the shape of an object without contact.

  Three-dimensional shape measurement is used not only in industry but also in many areas of society, such as medical research, biology, archeology, and research and restoration of fine arts. In the three-dimensional measurement, non-contact type optical measurement using light is desired rather than the conventional contact type. Optical measurement area measurement is classified into the optical cutting method that measures the area by scanning one linear slit light in the direction perpendicular to the slit direction, and the measurement method that measures in a unit of plane. Is done. The latter is more advantageous from the viewpoint of measurement time.

  The light cutting method is already a well-established technique, and various aspects have been developed to enable highly reliable measurement. However, “Three Dimensional Measurement” edited by Toru Yoshizawa [New Technology Communications] p. As shown in FIG. 31, it is pointed out that a mechanical movement mechanism such as a projection unit of slit light is required, and this becomes a bottleneck and the measurement time cannot be shortened and the efficiency is poor. Therefore, it is not suitable for a field where the measurement time needs to be shortened, and is used separately from surface measurement such as moire method and lattice pattern projection method described later. In addition, the light cutting method is based on the principle of so-called triangulation, and there is a problem that a large amount of time is required to determine the measurement parameter in calibration.

  On the other hand, typical methods for processing the surfaces collectively are the moire method (“Three-dimensional optical measurement” Toru Yoshizawa [New Technology Communications] p. 65), which acquires contour lines by moire fringes, and a striped grid. There is a grid pattern projection method (“Three-dimensional optical measurement” edited by Toru Yoshizawa [New Technology Communications] p. 83). In particular, the latter is expected now in view of measurement accuracy and the price of the apparatus.

  As shown in FIG. 1, the grid pattern projection apparatus normally captures a projection system 1000 including a projection unit 1000, a projector lens 1002, and a grid 1001, and a deformed grid pattern 1003 projected on the measurement object 1004 via the lens 1006. It can be divided into two systems, an imaging system including the imaging unit 1005. The projection unit 1000 projects a striped grid formed by the grid 1001 onto the measurement object 1004 via the lens 1002. The lattice pattern generated by the projection is deformed by the unevenness of the measurement object 1004. The imaging unit 1005 captures the deformed lattice pattern 1003 from an angle different from the projection direction, converts it into an electrical signal via a light receiving element such as a CCD (Charge Coupled Device), and stores the electrical signal in a storage device. By analyzing this, the three-dimensional shape of the measured object 1004 is measured. Each light receiving element outputs an electrical signal such as a voltage corresponding to the light intensity at that point. The lattice 1001 was previously created and fixed on the surface of glass, but recently, a lattice made of liquid crystal or the like has been put into practical use, and a high-speed ON / OFF of a fringe lattice realized in a liquid crystal device by a computer is performed at high speed. It comes to control.

Usually, a reference plane orthogonal to the optical axis of the projection unit 1000 is set, and two axes of the stripe direction Y and the stripe orthogonal direction X are set thereon. For details, see Non-Patent Document 1 (H. Lu et al., “Automatic Measurement of 3-D Object Shapes Based on Computer-generated Reference Surface”, Bull. Japan Soc. Of Prec. Eng. Vol. 21, No. 4, p251 (1987)), but in this method, the lattice pattern is expressed as a wave of light intensity I with respect to a position on the axis X orthogonal to the stripe, and the measured object 1004 is placed on the reference plane. The difference ΔΦ (= Φ ₂ −) between the wave phase Φ (= Φ ₂ ) or the wave phase Φ ₁ about the reference plane and the wave phase Φ ₂ when the measured object 1004 is placed on the reference plane. Analyze using Φ ₁ ). Thus, the grating pattern projection method is also called “modulated grating phase method”. The reason why the wave phase difference ΔΦ is used here is that the systematic error in the measurement is eliminated by subtraction, so that the accuracy is improved. In this method, the number of fringe waves (a pair of bright stripes and dark stripes) can be arbitrarily set as long as they are relative. In general, the phase angle is calculated as 2π with respect to one wavelength of the fringe wave.

A detailed calculation formula is disclosed in Non-Patent Document 1, and detailed description is omitted here. However, in order to obtain ΔΦ as shown in FIG. 1, Φ ₁ is the distance between the grating 1001 and the lens 1002, and imaging. Calculated from the optical geometric positional relationship such as the distance between the intersection of the optical axis of the unit 1005 and the optical axis of the projection unit 1000 and the lens 1002, the lattice spacing, the angle of the optical axis of the imaging unit 1005 and the optical axis of the projection unit 1000, etc. Ask for. These geometric positions naturally include measurement errors.

  In addition, Non-Patent Document 3 (Ken Yamatani et al., 3D shape measurement by liquid crystal lattice pattern projection, Journal of Precision Engineering, vol.67, No.5, p.786, (2001)) and Non-Patent Document 4 (Mitsuo Takeda et al., Fourier transform profilometry for the automatic measurement of 3-D object shapes, Applied OPTICS, vol. 22, no. 4, p. 3977 (1983)). Although a method for calculating the thickness is disclosed, both are calculated using the measurement result of the optical geometric position.

Note that (Φ ₂ = 2π × banding wave number + banding internal phase angle), which is obtained by measurement. Thus, in the method described above, it is particularly necessary to specify the fringe wave number.

  In order to obtain the fringe internal phase angle, scanning is performed along the X axis (see FIG. 1) in the fringe orthogonal direction set with respect to the reference plane. Even in the case of a so-called Ronchi grating in which the fringe grating is binarized as well as the sine wave grating, the vicinity of the border between the bright and dark fringes is on the reference plane due to the light diffraction phenomenon and the discretization error by the light receiving element. The light intensity I of the lattice pattern along the X axis in the fringe orthogonal direction varies. The light intensity distribution is recognized as a wave, and the phase angle in the fringe wave starting from the base point of the sine wave is obtained. In addition to the method of setting wave peaks and valleys to π / 2 and 3π / 2 (non-patent document 1 mentioned above), the method of setting the point that becomes the median value of the section from the valley to the peak to 0 in the fringe wave phase angle, etc. Exists. Whichever method is used, the fringe wave number changes at the point of the fringe internal phase angle 0, and one fringe wave is divided there.

The light intensity when the grating is shifted by π / 2, π, and 3π / 2 under the condition that a sine wave grating is used to determine the fringe internal phase angle is I ₀ , I ₁ , I ₂ , I _3. Then, it is known that the fringe internal phase angle at an arbitrary point x can be calculated by the following equation (Non-Patent Document 1). This method is a “position-fixed fringe internal phase angle calculation method”.

  In addition to this, there are a method of setting the point that becomes the median value of the section from the valley to the mountain to a fringe wave internal phase angle of 0, a method of detecting the peak of the valley and the mountain, and the like. The positions of the internal phase angles 0, π / 2, π, 3π / 2 are obtained by shifting by 2, π, 3π / 2, which is a “phase angle fixed position calculation method”. Whichever method is used, the fringe wave number changes at the point of the fringe internal phase angle 0, and one fringe wave is divided there.

  As described above, since the projected grating pattern 1003 is recognized as a wave of light intensity I, the phase Φ is expressed as 2π × the fringe wave number + the fringe internal phase angle. Therefore, in the lattice pattern projection method or the like, three-dimensional measurement cannot be performed unless the fringe wave number is known. When the fringe wave is continuous, the fringe wave number increases or decreases by 1 along the X axis, so that the phase difference ΔΦ can be easily calculated. However, the stripes may be discontinuous. When the fringes become discontinuous in this way, the continuity of the fringe wave numbers cannot be used, and therefore it is not easy to calculate the phase difference. In addition, if the fringe wave number is erroneously recognized, a measurement error occurs.

  On the other hand, as a method for automatically acquiring fringe wave numbers corresponding to the discontinuity of fringes, many studies have been conducted on black and white fringe gratings as summarized in Non-Patent Document 3 described below. Has been made. In addition, a method using a color fringe lattice is known (Patent Document 1 and Non-Patent Document 2).

  Japanese Patent Laid-Open No. 2003-65738 (Patent Document 2) discloses the following technique. That is, in order to perform camera calibration, a plane plate with markers with known XY coordinates is imaged a plurality of times at different Z-direction positions. As a result, camera parameters are calculated from the position of the marker on the image that is not on the same plane and the world coordinate position of each marker. Next, in order to obtain the fringe plane equation, the fringe space position is measured. At this time, the fringe pattern is projected onto the flat plate by the projection unit. The plane plate is moved, and images are captured by the imaging unit at least twice at different Z-direction positions. Then, for each projected stripe, spatial coordinates are acquired for at least three points Pa, Pb, and Pc that are included in the optical plane (a plane intersecting the XY plane) and are not in a straight line. For this purpose, arbitrary two points Qa and Qb on the straight line image by one stripe are determined in the image farther from the imaging unit. Pixel coordinate positions Qa (ua, va), Qb (ub, vb) of these points Qa, Qb are obtained. Similarly, in the image closer to the imaging unit, an arbitrary point Qc on the straight line image with the same stripe is determined. A pixel coordinate position Qc (uc, vc) of the point Qc is obtained. Using the pixel coordinate positions of these points Qa, Qb, Qc, distances z1, z2, and camera parameters, the positions Pa (xa, ya, z1), Pb (xb, yb, z1) and Pc (xc, yc, z2) are obtained. Such processing is performed for all stripes of the stripe pattern. The obtained position (coordinate data) of each point is stored in the storage device as a fringe space position. Further, each fringe plane equation is obtained based on the fringe space position and stored in the storage device. The fringe plane equation is generally expressed by the following equation. ax + by + cz = d. As data of the fringe plane equation, for example, parameters a, b, c, and d of this equation are stored. In the above description, the coordinate positions of three points are obtained for one stripe, but the coordinate positions of four or more points may be obtained by densely setting the Z coordinate position of the flat plate or the position on the image. . In that case, when those points are not on one plane, an approximate fringe plane equation is obtained. Thereby, a more accurate fringe plane equation is obtained.

  In such a technique, the purpose is to obtain a fringe plane equation for each fringe, so the relationship between the fringes is not grasped and the entire space cannot be represented correctly. Therefore, there are cases where a correct measurement value cannot be obtained. In addition, the calculation result of the camera parameter is used to calculate the fringe plane equation, but what kind of data the camera parameter is and its calculation method are not specified, and the camera parameter is calculated with sufficient accuracy. If not, the accuracy of the fringe plane equation will be reduced.

  The grating pattern projection method realized by the above-mentioned conventional technology is based on the assumption of a sine grating in the case of the “fixed-position fringe internal phase angle calculation method”, and the measurement accuracy depends on the degree of realization. Studies have been made to improve the degree (Non-patent Document 3). However, since the liquid crystal is a discrete type, it is clear that there is a limit to the degree of realization of the sine grating, which limits the accuracy. Further, in the conventional method, an effort is made to improve the accuracy of the coefficient of the calculation formula, but it is difficult to obtain highly accurate values for all points in the measurement volume. Furthermore, in the case of the “phase angle fixed type position calculation method”, different points are referred to, but an error occurs due to the difference in the brightness of the background of the reference point, and this limits the accuracy.

  Moreover, although the calculation formula for calculating (DELTA) (PHI) shown by the nonpatent literature 1, the nonpatent literature 3, and the nonpatent literature 4 contains a calibration parameter, this also contains an error and gives a restriction | limiting in precision. For example, when an error of 0.2% is included in the calibration parameter, if there is an error due to non-linearity, an error of 0.4 mm is generated when an object having a width of 200 mm is measured.

  Furthermore, these calculation formulas also have a problem that the horizontality of the measured values on the horizontal plane, which is industrially important, is not guaranteed when there is a systematic error in the received light data. The expression in Non-Patent Document 4 guarantees horizontality if there is no incidental error only with respect to the reference plane, but there is no guarantee for other horizontal planes.

  Moreover, the lattice pattern projection lens and the lattice pattern photographing lens have distortion. For example, when an object having a width of 200 mm is measured using a lens having a distortion aberration of 0.5%, an error of 1.0 mm is caused by the distortion. Although correction to some extent is possible, it is clear that there is a limit.

  Furthermore, optical calibration is performed on the measurement coordinate system. However, when the measurement device is attached to a CNC (Computer Numerical Control) device such as an NC (Numerical Control) machine tool and measured, and the CNC device is to be controlled using the measurement data, the measurement device and the machine tool are Does not match and has an error. In this case, it is desired to calibrate the measuring device in the coordinate system of the machine tool, but the method is not known at present.

  In addition, calibrating the parameters of a conventional measuring device with high accuracy requires high technology and a long time, and recalibration requiring accuracy is usually requested from the measuring device manufacturer. When the measuring device is used for production of products, there are economical problems such as production stoppage.

  Further, the conventional lattice pattern projection type measuring instrument as described above is portable or has a structure that is fixed to a specific structure (for example, a frame structure, an arm structure, etc.). In the former case, the measuring instrument is calibrated alone, and in the latter case, the calibration is performed in a state of being fixed to a specific structure.

  However, when a measuring instrument and an object to be measured are attached to a CNC device such as a machine tool, when trying to measure the object to be measured in an actual coordinate system such as a machine tool coordinate system, chips etc. It is necessary to detach the measuring instrument for the purpose of preventing it from coming into contact with the instrument.

  In this case, there is a problem that the measurement accuracy is lowered due to remounting, specifically, the measured value is inconsistent with the coordinate system displayed on the control panel of the machine tool. In order to cope with this problem, a certain degree of accuracy can be achieved by mounting and fixing the measuring instrument to a CNC device such as a machine tool using pins. However, in consideration of workability, a certain amount of clearance must be given to the fitting hole. This clearance is enlarged as an error. In addition, errors such as distortion due to stress at the time of mounting and acceleration of the change over time of the measuring instrument due to desorption are inevitable.

  Therefore, it is only necessary to recalibrate the measuring instrument, but recalibration is not efficient. As mentioned above, the calibration takes a relatively long time. However, an efficient method for remounting the instrument was not known, and it was considered impossible without recalibration.

  Further, for example, when performing absolute value measurement using a grid pattern projection type measuring instrument in the coordinate system of a machine tool, there is also a problem that the measured value changes due to a temperature change of the measuring instrument itself or the environment / state. Normally, measuring instruments and objects to be measured are placed in a temperature-controlled room and measured. When measuring with a measuring instrument attached to a CNC device such as a machine tool, the environment / state such as temperature changes. There is no known way to deal with it efficiently.

Japanese Patent Laid-Open No. 3-192474 JP 2003-65738 A H. Lu et al., "Automatic Measurement of 3-D Object Shapes Based on Computer-generated Reference Surface", Bull. Japan Soc. Of Prec. Eng. Vol. 21, No. 4, p251 (1987) W. Liu et al., Color Coded Projection Grating Method for Shape Measurement with a Single Exposure, Applied Optics Vol.39, No.20, p3503 (2000) Ken Yamatani et al., 3D shape measurement by liquid crystal lattice pattern projection, Journal of Precision Engineering, vol.67, No.5, p.786, (2001) Mitsuo Takeda et al., Fourier transform profilometry for the automatic measurement of 3-D object shapes, Applied OPTICS, vol. 22, no. 4, p. 3977 (1983) By G. Farin, supervised by Fumihiko Kimura, translated by Yasushi Yamaguchi, “Curve and Surface Theory for CAGD”, Kyoritsu Shuppan, 1991 Shape Processing Engineering (II) Fujio Yamaguchi, Nikkan Kogyo Shimbun Berthold K. P. Horn, Closed-form Solution of Absolute Orientation using Unit Quaternions, Optical Society of America, vol. 4.No. 4, p. 629, (1987) Takehisa Kuramoto, Yoshihiro Takebo, Toshihiro Kato, Katsuhisa Kajikawa "Development of high-precision optical measurement technology (1st report) Three-dimensional measurement by optical cutting method" Hiroshima Prefectural Industrial Technology Center Research Report No. 15 (2002) Greg Turk, Re-Tiling Polygonal Surfaces, Computer Graphics, vol. 26, no.2, (SIGGRAPH '92), p. 55-64

  As described above, in the prior art, various problems occur when the CNC device and the measuring instrument are made to cooperate.

  Therefore, an object of the present invention is to re-calibrate a measuring instrument such as a grid pattern projection type measuring instrument, for example, such as a reattachment or a temperature change, without recalibrating, for example, a machine tool coordinate system. It is to provide a technique for enabling measurement with high accuracy in a coordinate system different from the measuring instrument coordinate system.

  Another object of the present invention is to provide a novel measurement technique for removing systematic errors in the grid pattern projection method.

According to the present invention, a measurement method in a computer numerical control apparatus capable of mounting a measuring instrument for measuring an object shape includes a calibration step for calibrating the measuring instrument in a state of being mounted on the computer numerical control apparatus, and a re-measurement of the measuring instrument. When a change in a predetermined state including mounting occurs, measurement data obtained by a measuring instrument for three or more reference positions is acquired without performing calibration again, and conversion data for converting the measurement results to the reference position is obtained. and conversion data calculation step of calculating, performs measurement of the measurement object based on the calibration by instrument, and a measurement step of converting the measurement result by the conversion data.

  In this way, once calibration is performed in the calibration step, when a predetermined state change including remounting of the measuring instrument occurs, conversion data is calculated without performing recalibration, and the conversion data is used. It corrects the measurement result of the measuring instrument. Since the conversion data calculation step can be performed in a shorter time than the calibration of the measuring instrument, the measurement can be performed more efficiently than when calibration is performed again. At this time, the coordinate system of the measuring instrument is adjusted to the coordinate system of the computer numerical control apparatus because the measuring instrument is calibrated while being mounted on the computer numerical control apparatus such as a machine tool. It becomes possible to measure with high accuracy in the coordinate system.

  In the conversion data calculation step described above, the relative position of the reference object is moved by the computer numerical control device, the predetermined position of the reference object after the movement is used as the reference position, and the reference after the movement by the measuring instrument is used. An object shape of the object may be measured, and a measurement result by a measuring instrument corresponding to a predetermined position of the reference object may be acquired based on the measurement result. This is because the coordinate system of the measuring instrument is matched with the coordinate system of the computer numerical control apparatus, and therefore it is necessary to match the coordinate system when calculating the conversion data.

  In addition, the change in the predetermined state may include detecting a temperature change or time lapse of a predetermined threshold value or more. For example, a temperature rise by a temperature sensor or a time lapse by a timer may be detected.

  Furthermore, the measurement step includes a step of measuring the first portion of the object to be measured by the measuring instrument, a step of moving the relative position of the object to be measured by the computer numerical control device, and a step of measuring after the movement by the measuring instrument. A step of measuring the second part of the measurement object, and moving the measurement result of the first part or the second part of the measurement object using the movement data of the measurement object; And a synthesis step for synthesis. This is processing when the object to be measured cannot be measured at a time.

  In addition, the measuring instrument described above can be a grid pattern projection type measuring instrument having a projection unit that projects a predetermined grid pattern onto a specific object and an imaging unit that captures the specific object. The above-described calibration step is performed by projecting the projected grid pattern projected onto the surface, which is a specific object, by the projecting unit for each of the plurality of height surfaces realized by the computer numerical control device. From the image, a first set including a set of coordinates (for example, (x, y)) of the number of points in the vertical direction and the horizontal number common to each of the light receiving surfaces of the photographing unit and the light intensity and height of the point. Generating a set of the first set of data and storing the data of the first set in a storage device; converting the light intensity into a phase angle of the projection grating pattern; And each pair It may include a step of storing the data of the second set for constructing a rectangular grid in the storage device as over de.

  In this way, by holding the second set including a plurality of sets of coordinates and heights on the light receiving surface of the imaging means and the phase angle of the projected grating pattern, the observation side of the coordinates on the light receiving surface and the phase angle of the projected grating pattern is maintained. Thus, the height of the object to be measured can be derived from the coordinates on the light receiving surface and the phase angle of the projected grating pattern at the time of measurement. As described above, since calibration is performed only with the measurement data, the systematic error disappears. A flat surface is more advantageous in terms of device manufacturing and accuracy maintenance, but even a curved surface has no problem in realizing the function.

  Further, it may further include a hypersurface generation step of generating data representing a tensor product type complex hypersurface from the second set of data and storing the data in a storage device. Thus, in the present invention, in the form of a tensor product type complex hypersurface in a four-dimensional space (four dimensions in total (coordinate (two-dimensional), phase angle (one-dimensional) and height (one-dimensional) on the light receiving surface)). The relationship between coordinates, phase angle and height on the light receiving surface is expressed. The tensor product type compound hypersurface in the four-dimensional space is obtained by increasing the dimension of the tensor product type compound hypersurface in the three-dimensional space by one.

  As described in detail in Non-Patent Document 5, the tensor product type compound curved surface in the three-dimensional space is “a curved surface that moves in space while changing its shape (hereinafter referred to as“ first curve ”). The first moving point is expressed using a control point (hereinafter referred to as “first control point”), and the first control point is a certain curve (hereinafter referred to as “first curve”). The first control point is expressed using a further different control point as the one that moves along the second curve).

Since the first curve moves along the second curve, the number of control points expressing the first curve is the same as the number of control points expressing the second curve. A rectangular grid is constructed from a common number of vertical and horizontal points.
The tensor product type compound hypersurface in four dimensions is regarded as “the hypersurface is a trajectory of a curved surface that moves in a space while changing its shape”. 2), and the second control point moves along a third coordinate (for example, time), and the second control point is further changed to a third control point. It can be obtained by using and expressing. The tensor product type complex hypersurface generated in this way is approximate, but sufficient accuracy can be obtained if the number of pairs included in the second set is sufficiently large.

  As an expression of this tensor product type composite hypersurface, a formula obtained by increasing the order of a Bezier surface or a B-Spline surface by one can be used. The tensor product type complex hypersurface in the present invention includes one obtained by increasing the degree of a rational Bezier surface or a rational B-Spline surface obtained by projective transformation of the tensor product type complex surface.

  In addition, the coordinates on the light receiving surface of the photographing unit are obtained from the photographed image of the projected grid pattern projected by the projecting unit and photographed by the photographing unit during measurement by the measuring instrument in the conversion data calculating step and the measuring step. And extracting the data of the set of light intensity and storing it in the storage device, converting the light intensity into the phase angle of the projection grating pattern, and storing the data of the set of coordinates and phase angle on the light receiving surface in the storage device And interpolating the height data corresponding to the coordinate and phase angle data on the light receiving surface using the data representing the tensor product type complex hypersurface, and further including an interpolation step of storing in the storage device Good.

  Interpolation data of measurement results can be obtained under the same conditions as during calibration except for the inclination of the measurement surface, so that the influence of the accuracy of the grid pattern and the accuracy of the calibration parameters can be reduced. In addition, since the measurement is performed on the flat surface at the same condition as that at the time of calibration, the horizontality and flatness can be guaranteed. The interpolation can be performed by giving a coordinate and a phase angle on the light receiving surface and referring to the hypersurface and solving the intersection problem between the hypersurface and the straight line. This can be solved, for example, by Jacobian inversion, which is a multidimensional Newton method.

  Furthermore, in the calibration step described above, each surface including a plurality of points having one or more heights and whose real coordinates are known was photographed by the photographing means without projection of the grid pattern by the projecting means. A third set including a plurality of sets of coordinates on the light-receiving surface of the photographing unit, the actual coordinates of the points, and the height is generated from a captured image of the surface that is a specific object, and the data of the third set is stored in the storage device The method may further include a step of storing in.

  In this way, not only the phase angle of the projected grating pattern but also the actual coordinates can be expressed appropriately by representing the set of coordinates and heights on the light receiving surface. A flat surface is more advantageous in terms of device manufacturing and accuracy maintenance, but even a curved surface has no problem in realizing the function.

  Then, it may further include a second hypersurface generation step of generating data representing the second tensor product type complex hypersurface from the third set and storing the data in the storage device.

  Further, by using the data representing the second tensor product type complex hypersurface, interpolation calculation is performed for real coordinate data corresponding to the data of the set of height data generated in the interpolation step and the corresponding coordinate on the light receiving surface, and stored. You may make it further contain the step stored in an apparatus.

  In this way, it becomes possible to remove lens distortion and the like. In addition, about the X-axis direction and Y-axis direction of a substance, space can be represented even if it uses a curved surface instead of a hypersurface.

  The measurement method of the present invention is implemented by a combination of a computer and a program, for example, and this program is stored in a storage medium or storage device such as a flexible disk, a CD-ROM, a magneto-optical disk, a semiconductor memory, or a hard disk. Moreover, it may be distributed as a digital signal via a network or the like. The intermediate processing result is temporarily stored in a storage device such as a main memory.

  According to the present invention, a measuring instrument coordinate such as a machine tool coordinate system can be used without recalibrating a measuring instrument such as a grid pattern projection type measuring instrument even if a state change such as remounting or temperature change occurs. It becomes possible to measure with high accuracy in a coordinate system different from the system.

  As another aspect, systematic errors can be removed in the grid pattern projection method.

FIG. 2 shows a functional block diagram in one embodiment of the present invention. A CNC device (for example, a machine tool, but not limited thereto) including a measurement unit in the present embodiment includes an image processing device 5 that performs the main processing in the present embodiment and is a computer, A liquid crystal projector 1 that is connected to the image processing device 5 and includes a projection unit 11 such as a lamp, a liquid crystal panel 12 for forming a lattice, and a lens 13, and a lens 41 that is connected to the image processing device 5. And a camera 4 having a CCD 42 and a memory (not shown), a reference plane 2 serving as a reference plane at the time of calibration (provided that the reference plane when the height Z = Z ₁ is 2a, and the reference plane when the height Z = Z ₂ is 2b), and a movement control unit that is connected to the image processing apparatus 5 and executes movement control such as movement of the reference plane 2 in at least the Z direction and translation / rotation / tilting of the object to be measured. It includes a control unit 6 and a temperature sensor 7 connected to the image processing device 5 and measuring the temperature in the CNC device. On the reference plane 2, the fringe orthogonal direction of the projected grating pattern is taken as the X axis, the fringe direction is taken as the Y axis, and the optical axis of the camera 4 is provided in the Z axis direction. On the other hand, also on the light receiving surface of the CCD 42, the fringe orthogonal direction of the projected grating pattern image is taken as the x axis and the fringe direction is taken as the y axis. Note that the uppercase XYZ represents an axis or coordinates in real space, and the lowercase xy represents an axis or coordinates of an image on the light receiving surface. In the present embodiment, the measurement unit including the liquid crystal projector 1, the camera 4, a power supply device (not shown), and the like can be detached from other parts of the CNC device. Incidentally, although the lattice pattern projection method with good measurement efficiency is illustrated here, it is not necessarily limited to this. In other words, other methods such as the light cutting method and the moire method can be realized by the same method.

  The image processing apparatus 5 includes a main control unit 500 that controls the entire image processing apparatus 5, a camera control unit 51 that controls the camera 4, a projection control unit 52 that controls the liquid crystal projector 1, and a calibration control unit. The calibration processing unit 53 that performs image processing and the like and the movement control unit 6 are caused to change the height Z of the reference plane, and rotate, tilt, and translate the reference object (for example, a sphere) and the object to be measured. CNC data setting unit 54 for setting CNC data for control, a control point generation unit 55 for generating a control point such as a tensor product type complex hypersurface, which is a part of processing performed at the time of calibration, and a measurement target at the time of measurement An actual coordinate calculation unit 56 that calculates the actual coordinates of the object, a synthesis processing unit 59 that performs processing necessary to synthesize measurement data for a plurality of times when the object to be measured is measured in multiple times, and measurement Part Temperature measured by the case and the temperature sensor 7 which is remounted to the CNC device contains a correction processor 60 which performs processing required for correction of the measurement data performed when a condition exists. The image processing apparatus 5 also stores a calibration data storage unit 57 that stores control point data such as a tensor product type complex hypersurface generated at the time of calibration, and actual coordinate data of the object to be measured that is generated at the time of measurement. A measurement data storage unit 58 for storing data, a synthesis data storage unit 61 for storing data for synthesis that is data for synthesis of measurement data, and correction data that is data for correction processing of measurement data. The correction data storage unit 62 is managed.

  Next, a processing flow of processing using the CNC device according to the present embodiment will be described with reference to FIG. First, a removable measuring unit is attached to the CNC device (step S100). Note that this step is not performed unless the measurement unit is removed from the CNC device, and is indicated by a dotted line block. In the case of a machine tool, the measuring unit is mounted on the blade attachment side. In the present embodiment, it is preferable that the pin can be fixed at the same position as much as possible. Next, calibration processing is performed (step S102).

Details of the calibration process will be described with reference to FIGS. For example, when the user instructs the image processing apparatus 5 to execute the calibration process, the main control unit 500 receives the instruction and instructs the CNC data setting unit 54 to perform a calibration process. In response to an instruction from the main control unit 500, the CNC data setting unit 54 outputs, for example, setting data of a preset height Z (= Z ₁ ) to the movement control unit 6, and the movement control unit 6 According to the setting data of the height Z (= Z ₁ ) received from the setting unit 54, the height of the reference plane 2 is controlled to become the height Z ₁ . In response to an instruction from the main control unit 500, the projection control unit 52 controls the liquid crystal projector 1 so as to project a predetermined lattice pattern onto the reference plane 2a. In response to an instruction from the projection control unit 52, the liquid crystal projector 1 forms a predetermined lattice pattern on the liquid crystal panel 12, and the projection unit 11 applies the predetermined lattice pattern formed by the liquid crystal panel 12 to the reference plane 2a. Project. In response to an instruction from the main control unit 500, the camera control unit 51 controls the camera 4 so as to capture the projection grid pattern. In response to an instruction from the camera control unit 51, the camera 4 performs imaging using the CCD 42. The captured image data obtained by the CCD 42 is temporarily stored in the memory in the camera 4 and then output to the image processing device 5. The image processing device 5 stores the captured image data in a storage device such as the calibration data storage unit 57, for example.

Next, the CNC data setting unit 54 outputs, for example, setting data for another preset height Z (= Z ₂ ) to the movement control unit 6, and the movement control unit 6 receives from the CNC data setting unit 54. According to the setting data of the height Z (= Z ₂ ), the height of the reference plane 2 is controlled to become the height Z ₂ . Then, the projection control unit 52 controls the liquid crystal projector 1 so as to project a predetermined lattice pattern onto the reference plane 2b. In response to an instruction from the projection control unit 52, the liquid crystal projector 1 forms a predetermined lattice pattern on the liquid crystal panel 12, and the projection unit 11 applies the predetermined lattice pattern formed by the liquid crystal panel 12 to the reference plane 2a. Project. Since the projection is performed once at the height Z ₁ , the process in the projection control unit 52 and the liquid crystal projector 1 is unnecessary if the projection is continued as it is. Then, the camera control unit 51 controls the camera 4 so as to capture the projection grid pattern. In response to an instruction from the camera control unit 51, the camera 4 performs imaging using the CCD 42. The captured image data obtained by the CCD 42 is temporarily stored in the memory in the camera 4 and then output to the image processing device 5. The image processing device 5 stores the captured image data in a storage device such as the calibration data storage unit 57, for example.

  The above process is repeated by changing the height Z of the reference plane 2 (step S1). At this time, the height Z of the reference plane 2 needs to be changed at least once, but is preferably changed twice or more. The larger the number, the more accurate the approximation.

A conceptual diagram of photographing in step S1 is shown in FIGS. FIG. 5A is a schematic diagram when the Z axis shown in FIG. 2 is perpendicular to the line of sight. The projection grid pattern is projected onto the reference plane 2 by irradiating light through the liquid crystal panel 12 provided in the liquid crystal projector 1 and having a predetermined grid pattern formed thereon. In FIG. 5A, the height that is the lower limit of measurement is indicated by a straight line 422, and the height that is the upper limit of measurement is indicated by a straight line 421. A straight line parallel to the straight lines 421 and 422 and having a constant height represents the reference plane 2. Here, four reference planes from Z ₁ to Z ₄ are shown. Further, in the projected grating pattern, for example, straight lines in which light is blocked in the liquid crystal panel 12 and the phase angle Φ is constant are represented by straight lines 411 to 416. That is, the phase angle Φ is constant on any one of the straight lines 411 to 416 and is represented by a black line on any of the reference planes 2. The imaging range is a range surrounded by straight lines 401 and 402, and a range further surrounded by a straight line 421 representing the upper limit of measurement and a straight line 422 representing the lower limit of measurement is a measurement range (measurement volume).

In such a situation, when the projection grid pattern projected on the reference plane 2 via the lens 41 in the CCD 42 is imaged, for example, as shown in FIGS. 5B and 5C. It is assumed that light is blocked only by the portions represented by the straight lines 411 to 416, and that there are 20 light receiving elements (represented by circles) in the x-axis direction and 10 light receiving elements in the y-axis direction of the CCD 42. . Further, FIG. 5 (b) the case is of Z = Z ₁ a reference plane 2a, FIG. 5 (c) shall be respectively show the case is of Z = Z ₂ a reference plane 2b. In FIG. 5B and FIG. 5C, a white circle indicates a light receiving element that detects light, and a black circle indicates a light receiving element that does not detect light. When the heights Z are different, the shadows represented by the straight line 412, the straight line 413, the straight line 414, and the straight line 415 are detected by different light receiving elements. That is, when the height of the reference plane 2 is different, the coordinates on the light receiving surface where the phase angle Φ in the projection grating pattern is the same are different. Here, a state is shown in which only the four rows of light receiving elements corresponding to the four straight lines 412 to 415 do not detect light, and the remaining light receiving elements all detect light in the same manner. The light intensity that sequentially changes in the direction perpendicular to the stripes of the grating is detected in each light receiving element.

  Returning to the description of the processing flow in FIG. 4, in response to an instruction from the main control unit 500, the calibration processing unit 53 captures the captured image data captured in step S <b> 1 and the height Z set by the CNC data setting unit 54. Is used to create a set of data of the height Z, the light receiving coordinate (x, y) on the light receiving surface, and the light intensity I, and store the set of data in the calibration data storage unit 57 ( Step S2). More specifically, a set is generated in association with the coordinates (x, y) of each pixel of the captured image at a specific height Z, the light intensity I, and the specific height Z, for example, a calibration data storage unit 57. To store.

  An example of a data table stored in the calibration data storage unit 57 is shown in FIG. In the example of FIG. 6, for example, a column 501 of i that represents a light receiving element number (also referred to as a lattice number) in the Z direction, a column 502 of j that represents a lattice number in the x direction, and a k that represents a lattice number in the y direction, for example. Column 503, light receiving element x coordinate column 504, light receiving element y coordinate column 505, height Z (also called Z coordinate) column 506, light intensity I column 507, phase angle A column 508 is provided. Thus, the coordinates (x, y) on the light receiving surface of the light receiving elements arranged in j columns and k rows on the light receiving surface and the light intensity I when shooting at the i-th height Z with that light receiving element are one record. It is supposed to be registered. At this stage, the phase angle is not yet registered.

  Next, the calibration processing unit 53 converts the light intensity I of the data stored in the calibration data storage unit 57 into the phase angle Φ, and stores it in, for example, the data table of FIG. Step S3). In the grating pattern projection method, the method of calculating the phase angle Φ from the light intensity I has already been devised in addition to the equation (1) described in the background art section, and can be calculated using this technique. No further explanation here.

  Then, the control point generation unit 55 generates a control point for representing the tensor product type complex hypersurface using each set of the light receiving coordinate (x, y), the height Z, and the phase angle Φ as an input point, and calibration. The data is stored in the data storage unit 57 (step S4). A hypersurface means a figure obtained by giving one constraint in an n-dimensional space. The composite indicates that a plurality of patches are connected. The tensor product represents a multilinear space. The space represented by the set of the light receiving coordinates (x, y), the height Z, and the phase angle Φ obtained in step S3 can be represented by a four-dimensional tensor product type complex hypersurface. Uses a Bezier curved surface, a B-Spline curved surface, a rational B-Spline curved surface, a NURBS curved surface, or the like with an order increased by one. By using such a tensor product type complex hypersurface, the relationship between the height in the measurement range, the coordinates of the light receiving surface, and the phase angle can be expressed more accurately. Note that the tensor product type complex hypersurface interpolates the entire measurement volume including the measurement points, and it becomes an approximation, but because there is continuity, it is sufficient if the control points can be specified with more data Accuracy can be obtained.

  Here, the input points are of a rectangular lattice type as shown in FIG. That is, it is a structure in which FIG. 5B or FIG. However, it is only necessary to form a rectangular lattice in terms of phase, and it is not limited to a rectangular lattice combining cubes. Each lattice point P is specified by three parameters ijk, and each lattice point P represents a set of coordinates (x, y), height Z, and phase angle Φ on the light receiving surface.

  In this way, the input point group has a rectangular lattice structure as shown in FIG. 7, and the connectivity in the sweep direction is guaranteed in any of i, j, and k directions. Therefore, the control points may be obtained by sweeping i, j, and k independently. That is, as shown in FIG. 8, the input point sequence is swept in the first direction (for example, i) to generate a control point, and the data of the control point is stored in, for example, the calibration data storage unit 57 (step S11). . For example, after j and k are fixed and the input point sequence is swept in the i direction to generate control points, j or k is changed and the input point sequence is swept in the i direction to generate control points. By repeating this, all the control points are generated for the input point sequence extending in the i direction. Further, the control point is generated by sweeping the input point sequence in the second direction (for example, j), and the data of the control point is stored in the calibration data storage unit 57 (step S13). Here, for example, after fixing the i and k and sweeping the input point sequence in the j direction to generate the control points, the control points are generated by changing the i or k and sweeping the input point sequence in the j direction. . By repeating this, all control points are generated for the input point sequence extending in the j direction. In addition, about the control point already produced | generated by step S11, a control point is produced | generated using it as an input point. Then, the control point is generated by sweeping the input point sequence in the third direction (for example, k), and the data of the control point is stored in the calibration data storage unit 57 (step S15). For example, after i and j are fixed and the input point sequence is swept in the k direction to generate a control point, i or j is changed and the input point sequence is swept in the k direction to generate a control point. By repeating this, all control points are generated for the input point sequence extending in the k direction. Again, the control points generated in steps S11 and S13 are used as input points to generate control points.

  In the calibration data storage 57, the control points are stored in a data table as shown in FIG. 9, for example. In the example of FIG. 9, a control point number column 800, an x coordinate column 801, a y coordinate column 802, a Z coordinate column 803, and a phase angle column 804 are provided.

Specifically, a method for generating control points from input points will be briefly described. A case where a relatively simple cubic Bezier curve is used will be described. FIG. 10A shows an example of the input point sequence. Thus, it is assumed that there are input point sequences P ¹ , P ² , P ³ and P ⁴ . In such a case, two adjacent input points (for example, P ¹ and P ² ) are selected, and the respective tangent vectors (for example, m ¹ and m ² ) are obtained. Then, intermediate control points (P ¹¹ and P ¹² ) are obtained as follows. For details, see Non-Patent Document 5.

By repeating this, a control point sequence as shown in FIG. 10B can be obtained. In the Bezier curve, the input point sequences P ¹ , P ² , P ³ , and P ⁴ are also control points and are represented as P ¹⁰ , P ²⁰ , P ³⁰ , and P ⁴⁰ for distinction. That is, between the P ¹⁰ and P ^20, is generated P ¹¹ and P ^12, between P ²⁰ and P ^30, it is generated P ²¹ and P ^22, between P ³⁰ and P ^40, P ³¹ and P ³² are generated.

但し、Ｂ_i ⁿ(t)＝_ｎＣ_ｉｔⁱ(１−ｔ）^n-i
であって、Bernstein多項式である。Bernstein多項式についても非特許文献５を参照されたい。なお、Ｐ_ijkは制御点である。（２）式は従来から知られているベジエ曲面（例えば非特許文献５記載）の以下の式に対して次元の拡張を行ったものである。

Based on the control points thus obtained, the Bezier hypersurface is represented by the following expression for each three-dimensional hyperpatch corresponding to a one-dimensional segment or a two-dimensional patch.

Where B _i ⁿ (t) = _n C _i t ⁱ (1−t) ⁿⁱ
And it is a Bernstein polynomial. See also Non-Patent Document 5 for Bernstein polynomials. P _ijk is a control point. Expression (2) is obtained by extending the dimension of the following expression of a conventionally known Bezier curved surface (for example, described in Non-Patent Document 5).

In this embodiment, not only a Bezier curve but also a uniform B-Spline curve can be used. A case of a cubic B-Spline curve will be described with reference to FIG. Here, P ¹ ,... P ⁱ , P ^{i + 1} ... P ⁿ are input point sequences. On the other hand, the control points of the B-Spline curve are Q ⁰ , Q ¹ ,... Q ⁱ⁻¹ , Q ⁱ , Q ^{i + 1} , Q ^{i + 2} , ... Q ⁿ , Q ^{n + 1} The input point sequence P and the control point sequence Q correspond to each other with the same superscript suffix, and only Q ⁰ and Q ^{n + 1} are additionally provided. That is, the number of control points is smaller than in the case of Bezier, and the memory capacity for holding control point data is small.

を計算し、δ_i＋Ｑⁱを、新たなＱⁱに設定する。なお、Ｑ⁰についてはＱ¹と同じに設定する。また、Ｑⁿ⁺¹をＱⁿと同じに設定する。 In order to generate a control point sequence as shown in FIG. 11, Q ⁱ is set equal to P ⁱ for i = 1 to n as the first step. Q ⁰ is set to be the same as Q ¹ . Q ^{n + 1} is set to be the same as Q ⁿ . For i = 1 to n as the second step,

And δ _i + Q ⁱ is set to a new Q ⁱ . Q ⁰ is set to be the same as Q ¹ . Q ^{n + 1} is set to be the same as Q ⁿ .

In the third step, it is determined whether max {δ _i }> δs (fixed value). If this condition is satisfied, the process returns to the second step. On the other hand, if this condition is not satisfied, the process is terminated. In this way, the control point sequence can be calculated. For details, see pages 69 to 72 of Non-Patent Document 6.

なお、Ｑ_ijkは制御点である。 Based on the control points thus obtained, the B-Spline hypersurface is expressed by the following equation for each three-dimensional hyperpatch corresponding to a one-dimensional segment or a two-dimensional patch.

Q _ijk is a control point.

  In addition, NURBS, rational B-Spline, and the like can be used, and are not limited to Bezier and B-Spline.

  By performing the processing as described above, it is possible to obtain data representing a tensor product type complex hypersurface called a control point, and to obtain the height Z at the time of measurement described below.

  In addition, although the example which comprises a grid point about the pixel of the form where the position of a picked-up image is fixed was shown above, it is not necessarily limited to this, For example, a grid point is comprised only about the pixel of a specific phase angle. You may make it do.

Returning to the description of FIG. 4, the CNC data setting unit 54 outputs, for example, setting data of a preset height Z (= Z ₁ ) to the movement control unit 6 in response to an instruction from the main control unit 500. The movement control unit 6 controls the height of the reference plane 2 to be the height Z ₁ according to the setting data of the height Z (= Z ₁ ) received from the CNC data setting unit 54.

  In this step, a solid grid pattern with a known X coordinate value, Y coordinate value, or X and Y coordinate values is drawn on the reference plane 2 (or an object on which the solid grid pattern is drawn is placed). Shall. For example, as shown in FIG. 12 (a), an actual lattice pattern that is parallel to the Y axis and has a known X coordinate, and as shown in FIG. 12 (b), an actual lattice pattern that is parallel to the X coordinate and has a known Y coordinate. Are prepared separately and the following processing is performed. Alternatively, as shown in FIG. 12C, an intersecting lattice pattern that is a combination of an actual lattice pattern that is parallel to the X axis and has a known Y coordinate and an actual lattice pattern that is parallel to the Y axis and has an known X coordinate is used. Anyway. In response to an instruction from the main control unit 500, the projection control unit 52 controls the liquid crystal projector 1 so that light is emitted as illumination instead of a lattice pattern. In response to an instruction from the projection control unit 52, the liquid crystal projector 1 irradiates the reference plane 2 a with light from the projection unit 11 without forming a lattice pattern on the liquid crystal panel 12.

  Then, in response to an instruction from the main control unit 500, the camera control unit 51 controls the camera 4 so as to photograph the actual lattice pattern. In response to an instruction from the camera control unit 51, the camera 4 performs imaging using the CCD 42. The captured image data obtained by the CCD 42 is temporarily stored in the memory in the camera 4 and then output to the image processing device 5. The image processing device 5 stores the captured image data in a storage device such as the calibration data storage unit 57, for example.

Next, the CNC data setting unit 54 outputs, for example, setting data for another preset height Z (= Z ₂ ) to the movement control unit 6, and the movement control unit 6 receives from the CNC data setting unit 54. According to the setting data of the height Z (= Z ₂ ), the height of the reference plane 2 is controlled to become the height Z ₂ . Then, the camera control unit 51 controls the camera 4 so as to photograph the actual lattice pattern. In response to an instruction from the camera control unit 51, the camera 4 performs imaging using the CCD 42. The captured image data obtained by the CCD 42 is temporarily stored in the memory in the camera 4 and then output to the image processing device 5. The image processing device 5 stores the captured image data in a storage device such as the calibration data storage unit 57, for example.

  The above process is repeated by changing the height Z of the reference plane 2 (step S5). At this time, the height Z of the reference plane 2 needs to be changed at least once, but is preferably changed twice or more. The larger the number, the more accurate the approximation.

  Next, in response to an instruction from the main control unit 500, the calibration processing unit 53 reads out the captured image data stored in, for example, the calibration data storage unit 57, extracts the light receiving pixels of the actual lattice pattern in the captured image, and Data of a set of the light receiving coordinates (x, y) and height Z of the light receiving pixels and the actual coordinate values (X coordinate, Y coordinate, or X coordinate and Y coordinate) of the actual grid, for example, calibration data storage unit 57 (Step S6). For example, if the solid lattice pattern is a black line and the other surfaces are white, pixels that are determined to be black based on the value of the light intensity I can be extracted. In addition, if it is possible to specify the entity grid pattern of which entity coordinate the black line corresponds to by using a method such as attaching a marker to the end of the line, the actual coordinate corresponding to the extracted pixel is changed. Can be identified.

  FIG. 13 shows an example of a data table stored in the calibration data storage unit 57. In the example of FIG. 13, for example, an i column 1501 that represents a light receiving element number (also referred to as a lattice number) in the Z direction, a j column 1502 that represents the lattice number in the x direction, and a k that represents the lattice number in the y direction, for example. Column 1503, x-coordinate column 1504 of the light-receiving element, y-coordinate column 1505 of the light-receiving element, X-coordinate column 1506 in real space, Y-coordinate column 1507 in real space, and height Z column 1508 and a column 1509 of light intensity I are provided. As described above, the coordinates (x, y) on the light receiving surface of the light receiving element extracted j-th in the x-direction and k-th in the y-direction on the light-receiving surface, the height Z and the light intensity I at that time, and the specified actual Coordinates (X coordinate, Y coordinate or X coordinate and Y coordinate) are registered as one record. The actual coordinate may be registered only in the X coordinate or only in the Y coordinate. In this example, only the X coordinate is specified.

  In this way, the first set of the set of the light receiving coordinate (x, y), the height Z and the real coordinate X, and the second set of the set of the received light coordinate (x, y), the height Z and the real coordinate Y are arranged. A set is obtained. Therefore, the control point generation unit 55 generates the control point by performing the processing described in relation to step S4 using each set included in the first set or the second set as an input point. The point data is stored, for example, in the calibration data storage unit 57 (step S7).

  For example, a data table for control points as shown in FIGS. 14 (a) and 14 (b) is stored in the calibration data storage unit 57. In the example of FIG. 14A, a control point number column 1601, an x coordinate column 1602, a y coordinate column 1603, a Z coordinate column 1604, and an X coordinate column 1605 are provided. In the example of FIG. 14B, a control point number column 1611, an x coordinate column 1612, a y coordinate column 1613, a Z coordinate column 1614, and a Y coordinate column 1615 are provided. Yes. Thus, the control point group for obtaining the X coordinate and the control point group for obtaining the Y coordinate are stored separately.

  As described above, since the data representing the tensor product type complex hypersurface is obtained for the X coordinate, the Y coordinate, and the Z coordinate, if the measurement process described below is performed, the coordinates of the point in the measured object are acquired. Will be able to.

  Note that in steps S1 and S5, the reference plane may be moved to the same height Z once by switching the presence / absence of the actual lattice pattern by photographing the reference plane having the same height Z.

  In any case, the height Z of the reference plane is 2 or more, but in order to increase the accuracy, the above processing should be performed at a higher height, and it takes a long time to perform the calibration processing. I understand that.

  Returning to the description of FIG. 3, next, the synthesis processing unit 59 performs a process of generating synthesis parameters necessary for performing the measurement data synthesis process in accordance with an instruction from the main control unit 500 (step S <b> 104). . The reason why this step is necessary will be outlined with reference to FIG. In FIG. 15, it is assumed that light from the liquid crystal projector 1 is irradiated from the right side to the left side. At this time, for example, when the object to be measured 160a, which is a sphere, is photographed by the camera 4 from the same direction as the liquid crystal projector 1, the A side of the object to be measured 160a can be photographed, so that measurement data can be obtained from the photographing result. However, measurement cannot be performed because the B side of the object 160a to be measured is shaded and cannot be photographed. Accordingly, the object to be measured 160a is moved by rotating (or inclining / translating) the rotating tilt base on which the object to be measured 160a is installed by the movement control unit 6, and the entire object to be measured 160a is moved multiple times. The entire image of the object to be measured 160a is measured by separately shooting with the camera 4. In the example of FIG. 15, the object to be measured 160a is moved to the position of the object to be measured 160b by rotating the rotary tilt table. Then, the light from the liquid crystal projector 1 is irradiated on the B side of the measured object 160a so that the camera 4 can take a picture. In other words, the B side of the measurement object 160b is photographed by the camera 4, and measurement data can be obtained from the photographing result.

  However, if the measurement data is generated only by photographing, the A side of the measured object 160a and the B side of the measured object 160b are only measured independently. Therefore, if this is not combined, the entire measured object is measured. I can't get results. In the case shown in FIG. 15, the measurement can be performed by rotating the measurement result of either the object to be measured 160a or the object to be measured 160b according to the rotation angle. However, when a 3-axis NC milling machine (machining center) is used, the measurement result cannot be rotated and combined even if the rotation angle is clear because the rotation axis is unknown. The same applies when tilting.

  Therefore, in the present embodiment, for example, a sphere is arranged on a rotary tilting table and rotated around the rotation axis, and the outer shape of the sphere is measured by the method described below at three or more positions. Next, the composition processing unit 59 calculates the center coordinates of the sphere using the measurement result of the outer shape of the sphere. There are many methods for calculating the center coordinates of the sphere from the measurement result of the outer shape of the sphere. For example, Non-Patent Document 8 also shows an example. Basically, an algorithm that finds a point that minimizes the sum of squares of distances to a large number of measurement points on the spherical surface is used. Then, an axis passing point is calculated as a point that minimizes the sum of squares of the distance from the centers of three or more spheres. Further, the rotation axis (vector) is calculated by setting the normal direction of the plane formed by the centers of three or more spheres as the axial direction. If this rotation axis and the actual rotation angle can be obtained, for example, a rotation matrix and its inverse matrix in the case of rotating around the rotation axis can be derived using the method described in well-known Non-Patent Document 7. . Therefore, the synthesis parameter here is a rotation axis (point and direction vector) and is stored in the synthesis data storage unit 61. The tilt axis is calculated in the same manner and stored in the synthesis data storage unit 61. It is not necessary to calculate in advance the data necessary for the transformation matrix for translation. It is also possible to obtain a plurality of axis passing points and calculate the axes using interpolation or the sum of squared distances.

  In addition, in order to simplify the explanation, the object to be measured 160a is divided into two surfaces A and B. However, in reality, the entire object to be measured cannot be covered twice with respect to the viewing angle of the camera 4. There are many. Further, since the axis data can be automatically obtained for the 5-axis NC milling machine, this step can be skipped.

  Next, the measurement object is measured (step S106). However, since it is not necessary to carry out the measurement at this stage, it is represented by a dotted line block in FIG. Since the measurement process will be described in detail in step S118, the description is omitted here.

  Then, the measuring unit is removed from the CNC device before performing the processing (step S108). However, in some cases, the measurement unit may not be removed, and therefore, it is represented by a dotted line block. Thereafter, processing is performed (step S110). In addition, since it is not necessary to implement a process, it has shown with the dotted line block. Steps S108 and S110 are not particularly different from those in the prior art, and will not be described.

  Then, the main control unit 500 determines whether or not a state change has occurred before measuring the object to be measured (step S112). Whether the measurement unit once removed is detected to be mounted again (when a signal is detected by connecting the camera 4 and the liquid crystal projector 1 or when a remounting instruction input by the user is received), or a temperature sensor When it is determined from the signal from 7 that the temperature change has exceeded a predetermined threshold value, for example, when it is determined that the predetermined threshold value has been exceeded in the timer that started counting at the end of the previous measurement, or the operator changes the state as necessary If it is input that the state has changed, it is determined that a state change has occurred.

  If it is determined that a state change has occurred, the correction processing unit 60 performs correction data acquisition processing according to an instruction from the main control unit 500 (step S114). The outline of this step will be described with reference to FIGS. FIG. 16A shows a state immediately after calibration. Here, the center coordinates P (X1, Y1, Z1) of the sphere are associated with the coordinates p (x1, y1) on the CCD 42 (light receiving surface) of the camera 4. In addition, the center coordinate Q (X2, Y2, Z2) of the sphere is associated with the coordinate q (x2, y2) in the CCD 42 of the camera 4. Further, the center coordinate R (X3, Y3, Z3) of the sphere is associated with the coordinate r (x3, y3) in the CCD 42 of the camera 4. Such a correspondence is established in the state immediately after calibration, and accurate measurement is performed.

  After that, when the measurement unit is removed and remounted, as shown in FIG. 16B, for example, the camera 4 is tilted and mounted to become the camera 4 ′. As a result, the CCD 42 (light receiving surface) also tilts to become the CCD 42 '. Therefore, even if a sphere is arranged at the same position as shown in FIG. 16A, it is measured as a different position. In other words, the center coordinate P (X1, Y1, Z1) of the sphere is not p (x1, y1) but p ′ (x1 ′, y1 ′) on the CCD 42 ′. P ′ (X1 ′, Y1 ′, Z1 ′) is measured. Similarly, since the coordinates of the center of the sphere Q (X2, Y2, Z2) on the CCD 42 'are not q (x2, y2) but q' (x2 ', y2'), The center coordinate is measured as Q ′ (X2 ′, Y2 ′, Z2 ′). Since the coordinates on the center of the sphere R (X3, Y3, Z3) are not r (x3, y3) but r ′ (x3 ′, y3 ′) on the CCD 42 ′, the center coordinates of the sphere are R ′. (X3 ′, Y3 ′, Z3 ′) is measured.

  In this step, in order to eliminate such inconvenience, first, the center coordinates of the sphere in the coordinate system of the CNC device are calculated in the state after the state change is detected. The center coordinates of the sphere in the coordinate system of the CNC device are obtained by measuring a large number of points on the spherical surface with, for example, a dial gauge, inputting the measurement result to the correction processing unit 60, and the measurement result input by the correction processing unit 60. The center coordinates of the sphere are calculated based on As described above, the calculation method is to obtain a point that minimizes the sum of squares of distances to a large number of measurement points on the spherical surface. Moreover, the measurement process in this Embodiment described below is implemented in the same state. The correction processing unit 60 similarly performs calculation of the center of the sphere. Thereby, the center of the sphere in the measurement coordinate system is calculated.

  Next, in response to an instruction from the main control unit 500, the CNC data setting unit 54 instructs the movement control unit 6 to move the ball by a predetermined amount, for example, translation, and the movement control unit 6 moves the ball according to the instruction. Here, the correction processing unit 60 calculates the center coordinates of the sphere in the coordinate system of the CNC device based on the movement amount. Moreover, the measurement process in this Embodiment described below is implemented in the same state. The correction processing unit 60 calculates the center coordinates of the sphere in the measurement coordinate system. This is repeated to calculate the center coordinates of the sphere at least at three locations.

  Then, the correction processing unit 60 converts P ′ (X1 ′, Y1 ′, Z1 ′) based on the measurement result by the measurement processing in the present embodiment to P (X1, Y1, Z1) based on the measurement result in the coordinate system of the CNC device. ), Q ′ (X2 ′, Y2 ′, Z2 ′) based on the measurement result by the measurement processing in this embodiment is changed to Q (X2, Y2, Z2) based on the measurement result in the coordinate system of the CNC device. A conversion matrix is calculated that converts R ′ (X3 ′, Y3 ′, Z3 ′) based on the measurement result of the measurement processing in the form into R (X3, Y3, Z3) based on the measurement result in the coordinate system of the CNC device. . A specific method for calculating this transformation matrix is disclosed in well-known Non-Patent Document 7. The calculated transformation matrix is stored in the correction data storage unit 62. If there is another known point without using a sphere, the process may be performed on that point. Further, since the relative position may be moved, the measuring unit may be moved without moving the sphere.

  When it is determined that there is no state change in step S112 or after step S114, the CNC data setting unit 54 captures the entire object to be measured by the camera 4 with respect to the movement control unit 6 in accordance with an instruction from the main control unit 500. The relative movement of the object to be measured is performed so as to be possible (step S116). In addition, you may make it implement relative motion of a measurement part and a to-be-measured object using a manual indexing apparatus. Further, movement data (rotation angle, inclination angle, translation vector) is stored in the composition data storage unit 61.

  And the measurement process of the to-be-measured object in this Embodiment is implemented (step S118). This process will be described with reference to FIG. The user first installs an object to be measured in the measurement volume. Then, a measurement instruction is issued to the main control unit 500 of the image processing apparatus 5. Then, the main control unit 500 instructs the projection control unit 52, and the projection control unit 52 controls the liquid crystal projector 1 so as to project a predetermined lattice pattern onto the object to be measured installed in the measurement volume. . In response to an instruction from the projection control unit 52, the liquid crystal projector 1 forms a predetermined lattice pattern on the liquid crystal panel 12, and the projection unit 11 forms the object to be measured on the reference plane 2 with the liquid crystal panel 12. A predetermined lattice pattern is projected. In addition, the camera control unit 51 controls the camera 4 so as to capture the projection grid pattern. In response to an instruction from the camera control unit 51, the camera 4 performs imaging using the CCD 42. The captured image data obtained by the CCD 42 is temporarily stored in the memory in the camera 4 and then output to the main control unit 500 of the image processing device 5. The image processing device 5 stores the captured image data in a storage device such as the measurement data storage unit 58 (FIG. 17: step S41).

  Next, in response to an instruction from the main control unit 500, the actual coordinate calculation unit 56 specifies a set of received light coordinates (x, y) and light intensity I based on, for example, photographed image data stored in the measurement data storage unit 58. For example, it is stored in the measurement data storage 58 (step S43). FIG. 18 shows an example of a data table stored in the measurement data storage unit 58. In the example of FIG. 18, a column 1801 of pixel (light receiving element) number, a column 1802 of the light receiving surface, a column of y coordinate 1803, a column of light intensity I 1804, a column of phase angle 1805, , Z coordinate column 1806, X coordinate column 1807, and Y coordinate column 1808. At this stage, only the x-coordinate, y-coordinate and light intensity I data are registered.

  Then, the actual coordinate calculation unit 56 converts the light intensity I into the phase angle Φ by referring to the data table (FIG. 18) stored in the measurement data storage unit 58 and the data in the measurement data storage unit 58. Store in the table (FIG. 18) (step S45). This process is the same as step S3 shown in FIG. 4, and is calculated using existing technology. Thereafter, the real coordinate calculation unit 56 calculates the height Z for each set of the received light coordinates (x, y) and the phase angle Φ by a multidimensional Newton method (for example, Jacobian inversion method). The data is stored in the stored data table (FIG. 18) (step S47).

The two-dimensional Jacobian inversion algorithm is described in Byoung K. Choi et al., Sculptured Surface Machining, Kluwer Academic Publishers, (1998). Here, a simple extension to three dimensions is applied. In the following, a simple explanation will be given. The calculation performed here is the parameter expression P (u, v, w) = (x (u, v, w), y (u, v) of the tensor product type complex hypersurface P. , w), Z (u, v, w), Φ (u, v, w)), Z corresponding to x ^* , y ^* and Φ ^* stored in the data table (FIG. 18) is obtained. It is a problem.

なお、ｘ_u(u₀,v₀,w₀)は、ｕ＝ｕ₀，ｖ＝ｖ₀，ｗ＝ｗ₀にて評価した偏導関数である。ｙ_u(u₀,v₀,w₀)及びΦ_u(u₀,v₀,w₀)についても同様である。 As a first step, initial estimated points u ₀ , v ₀ and w ₀ are given. Then, as a second step, δu, δv and δw are solved by the following three simultaneous equations.

X _u (u ₀ , v ₀ , w ₀ ) is a partial derivative evaluated with u = u ₀ , v = v ₀ , and w = w ₀ . The same applies to _yu (u ₀ , v ₀ , w ₀ ) and Φ _u (u ₀ , v ₀ , w ₀ ).

As a third step, u ₀ , v ₀ and w ₀ are updated as follows using δu, δv and δw obtained in this way.
u ₀ = u ₀ + δu
v ₀ = u ₀ + δv
w ₀ = w ₀ + δw

And as the fourth step,
(X ^* −x (u ₀ , v ₀ , w ₀ )) ² + (y ^* −y (u ₀ , v ₀ , w ₀ )) ² + (Φ ^* −Φ (u ₀ , v ₀ , w ₀₎ )) Evaluate ² and determine if this is small enough. In addition, the sum of absolute values may be used as the evaluation value. If it is sufficiently small, u = u ₀ , v = v ₀ , w = w ₀ obtained in the third step is the solution. On the other hand, if it is not sufficiently small, the process returns to the second step.

Finally, using the values u = u ₀ , v = v ₀ , and w = w ₀ obtained as solutions, for example, the height Z can be obtained by inputting into the equations (2) and (3). .

  If the above processing is performed, the height Z can be obtained. Further, the influence on the accuracy of the lattice pattern as a wave can be reduced. Further, the influence of the accuracy of the calibration parameter can be reduced. Further, with respect to the Z coordinate, the coordinate system of the measuring unit and the CNC device can be made uniform. In addition, since the measurement is performed under the same condition as that at the time of calibration on a plane having a constant height Z, horizontality can be guaranteed except for the accidental error.

  Next, the actual coordinate X is calculated by the multidimensional Newton method (for example, Jacobian inversion method) for each set of the received light coordinates (x, y) and the height Z, and the data table stored in the measurement data storage unit 58, for example. (FIG. 18) (step S49). In the description related to step S47, the portion that is Φ may be replaced with Z, and the same processing may be performed using the data of the control points shown in FIG. Then, the X coordinate of the real space can be obtained for each set of the light receiving coordinate (x, y) and the height Z.

  Similarly, the actual coordinate Y is calculated by the multidimensional Newton method (for example, Jacobian inversion method) for each set of the received light coordinates (x, y) and the height Z, and a data table stored in the measurement data storage unit 58, for example. (Step S51). In the description related to step S47, the portion Φ may be replaced with Z, and the same processing may be performed using the control point data shown in FIG. Then, the Y coordinate of the real space can be obtained for each set of the light receiving coordinate (x, y) and the height Z.

  By performing the processing as described above, the X coordinate value and the Y coordinate value of the object to be measured can be obtained. In addition, since the X coordinate and the Y coordinate can be calculated using the tensor product type complex hypersurface as described above, it is possible to reduce the influence of the distortion aberration of the photographing lens.

  Returning to the description of FIG. 3, in response to an instruction from the main control unit 500, the correction processing unit 60 uses the conversion matrix calculated in step S <b> 114 for the measurement result of the part to be measured that was included in the current measurement volume. Correction processing is performed (step S119). Since this process is only a matrix operation, it will not be described further. The result of the correction process is stored in the measurement data storage unit 58.

  Then, it is determined whether the end of measurement is instructed by the user (step S120). If it can be automatically determined whether the entire measured object or all necessary parts have been measured, the main control unit 500 determines. If the measurement is not finished, the process returns to step S112.

  On the other hand, when the necessary measurement processing is completed, the synthesis processing unit 59 performs measurement result synthesis processing in accordance with an instruction from the main control unit 500 (step S122). The synthesizing parameter generated in step S104 and the relative movement data stored in the synthesizing data storage unit 61 in step S116 are read, and a transformation matrix is calculated according to a method described in well-known Non-Patent Document 7. Since translation is relatively simple, an example thereof will be described with reference to FIG.

  In the example of FIG. 19, the entire object to be measured 180 a cannot be included in the measurement volume 182, so the measurement is performed in two steps. As a first step, measurement is performed on a portion of the measurement object 180a that has entered the measurement volume 182. Thereafter, correction processing is performed, and the corrected measurement result is stored in the measurement data storage unit 58. Then, as a second stage, the CNC data setting unit 54 sets data for moving the measured object 180a in translation by the vector V in FIG. The movement control unit 6 translates the measured object 180a by the vector V and places it at the position of the measured object 180b. Therefore, the measurement of the part entering the measurement volume 182 is performed. Thereafter, correction processing is performed, and the corrected measurement result is stored in the measurement data storage unit 58. Since P + V = P ′ at this time, the inverse transformation is P = P′−V. The synthesis processing unit 59 performs this processing for all the measurement points included in the measurement result in the second stage, and stores them in the measurement data storage unit 58.

  In order to finally combine the data, it is configured as data about one object to be measured by a method such as the highest point method or zippering, and is stored in the measurement data storage unit 58. This method is described in Non-Patent Document 9, for example.

  Then, the main control unit 500 determines whether the user has instructed that all the processes have been completed (step S124). If the process has not ended, the process returns to step S108. On the other hand, when the termination is instructed, the process is terminated.

  In this way, it is not necessary to repeatedly perform the calibration process shown in FIG. Further, it is possible to cope with errors due to remounting, errors due to temperature changes, passage of time, and the like. It is also possible to cope with changes with time other than temperature.

  In the measurement method described above (FIG. 17), the X coordinate and the Y coordinate are also obtained by the tensor product type complex hypersurface, but it is problematic even if the X coordinate and the Y coordinate are considered to be proportional to the height Z. Therefore, it can be calculated by a tensor product type compound curved surface. In the following description, processing when a tensor product type compound curved surface is used will be described.

  Processing at the time of calibration will be described with reference to FIG. First, calibration processing relating to the height Z is performed (step S60). Steps S1 to S4 in FIG. 4 are performed.

For example, when the user instructs the main control unit 500 of the image processing apparatus 5 to perform the calibration process, the main control unit 500 instructs the CNC data setting unit 54, and in response to this, the CNC data setting unit 54 The setting data of the preset height Z (= Z ₀ ) is output to the movement control unit 6, and the movement control unit 6 follows the setting data of the height Z (= Z ₀ ) received from the CNC data setting unit 54. The height of the reference plane 2 is controlled to be the height Z ₀ .

  At the time of this calibration, the reference plane 2 is provided with a solid grid pattern with known X-coordinate values, Y-coordinate values, or X and Y-coordinate values (or an object with the real grid pattern drawn). ) This is the same as step S5 in FIG. Further, the grid pattern is not projected by the liquid crystal projector 1.

  Then, in response to an instruction from the main control unit 500, the camera control unit 51 controls the camera 4 so as to photograph the actual lattice pattern. In response to an instruction from the camera control unit 51, the camera 4 performs imaging using the CCD 42. The captured image data obtained by the CCD 42 is temporarily stored in the memory in the camera 4 and then output to the image processing device 5. The image processing device 5 stores the captured image data in a storage device such as the calibration data storage unit 57 (step S61). In the above, shooting is to be performed for a plurality of reference planes 2 at a height, but it is sufficient here to capture a reference plane 2 having a single height.

  Next, in response to an instruction from the main control unit 500, the calibration processing unit 53 reads out the captured image data stored in, for example, the calibration data storage unit 57, extracts the light receiving pixels of the actual lattice pattern in the captured image, and Data of a set of a light receiving coordinate (x, y) of the light receiving pixel and a real coordinate value (X coordinate, Y coordinate or X coordinate and Y coordinate) of the actual lattice is stored in, for example, the calibration data storage unit 57 ( Step S63). This process is also almost the same as step S6 in FIG. 4, but since the height Z is the same in this step, the height Z may be stored separately. However, as shown in FIG. 13, the height Z may be stored in association with each other.

  In this way, a first set of sets of light receiving coordinates (x, y) and real coordinates X and a second set of sets of light receiving coordinates (x, y) and real coordinates Y are obtained. . Therefore, in response to an instruction from the main control unit 500, the control point generation unit 55 has been described in relation to step S4 (FIG. 4) using each set included in the first set or the second set as an input point. The control point is generated by performing the process, and the data of the control point is stored in, for example, the calibration data storage unit 57 (step S65). In step S7 in FIG. 4, the control points are calculated as data representing the tensor product type complex hypersurface. Here, the control points are calculated as data representing the tensor product type compound curved surface. The calculation method is basically the same, and the expressions (2) and (3) represented by u, v, and w are merely represented by u and v. The calibration data storage unit 57 stores control point data in the form shown in FIGS. 14 (a) and 14 (b). However, it is not necessary to store the height Z in association with each record.

  As described above, since the data representing the tensor product type compound curved surface is obtained for the X coordinate and the Y coordinate, the X coordinate and the Y coordinate can be acquired by performing the following measurement process. Become.

  At the time of measurement, the user first places an object to be measured in the measurement volume. Then, a measurement instruction is given to the main control unit 500 of the image processing apparatus 5. Then, in response to an instruction from the main control unit 500, the projection control unit 52 controls the liquid crystal projector 1 so as to project a predetermined lattice pattern onto the object to be measured installed in the measurement volume. In response to an instruction from the projection control unit 52, the liquid crystal projector 1 forms a predetermined lattice pattern on the liquid crystal panel 12, and the projection unit 11 forms the object to be measured on the reference plane 2 with the liquid crystal panel 12. A predetermined lattice pattern is projected. In response to an instruction from the main control unit 500, the camera control unit 51 controls the camera 4 so as to capture the projection grid pattern. In response to an instruction from the camera control unit 51, the camera 4 performs imaging using the CCD 42. The captured image data obtained by the CCD 42 is temporarily stored in the memory in the camera 4 and then output to the main control unit 500 of the image processing device 5. The main control unit 500 of the image processing apparatus 5 stores the captured image data in a storage device such as the measurement data storage unit 58 (FIG. 21: step S71). Same as step S41.

  Next, in response to an instruction from the main control unit 500, the actual coordinate calculation unit 56 specifies a set of received light coordinates (x, y) and light intensity I based on, for example, photographed image data stored in the measurement data storage unit 58. For example, it is stored in the measurement data storage 58 (step S73). Same as step S43.

  Then, the real coordinate calculation unit 56 refers to the data table stored in the measurement data storage unit 58, converts the light intensity I into the phase angle Φ, and stores it in the data table of the measurement data storage unit 58 ( Step S75). Same as step S3 and step S45. Thereafter, the real coordinate calculation unit 56 calculates the height Z for each set of the received light coordinates (x, y) and the phase angle Φ by a multidimensional Newton method (for example, Jacobian inversion method). Store in the stored data table (step S77). Same as step S47.

Next, the real coordinate calculation unit 56 calculates the actual coordinate X for each light receiving coordinate (x, y) by a multidimensional Newton method (for example, Jacobian inversion method), and further, height Z / height Z ₀ at the time of calibration. For example, the data is stored in the data table stored in the measurement data storage unit 58 (step S79). Processing of the first half, but can be calculated by two-dimensional Jacobian inversion method itself is written in the article mentioned above, wherein further, the X-coordinate values obtained by performing the Z / Z ₀ multiplied process , X coordinates corresponding to the light receiving coordinates (x, y). Since the X coordinate value is proportional to the height Z, it is corrected using the height Z ₀ at the time of calibration. In this way, the X coordinate of the real space is calculated for each set of the light receiving coordinate (x, y) and the height Z.

Similarly, the real coordinate calculation unit 56 calculates the actual coordinate Y by the multidimensional Newton method (for example, Jacobian inversion method) for each set of the received light coordinate (x, y) and the height Z, and further calculates the height Z / calibration. The height Z is multiplied by ₀ and stored in a data table stored in the measurement data storage unit 58, for example (step S81). Similar to step S79, the first half of the processing can be calculated by the two-dimensional Jacobi inversion method itself described in the above-mentioned paper, but here, the obtained Y coordinate is further multiplied by Z / Z _0. To obtain the Y coordinate corresponding to the light receiving coordinate (x, y). In this way, the Y coordinate of the physical space is calculated for each set of the light receiving coordinate (x, y) and the height Z.

  If the above processing is performed, the X coordinate and the Y coordinate can be calculated without using the tensor product type complex hypersurface. Since the order is low in one dimension, the calculation load can be kept low.

  Although one embodiment of the present invention has been described above, the present invention is not limited to this. That is, the functional block diagram shown in FIG. 2 is an example, and the functional blocks in the image processing apparatus 5 do not necessarily correspond to the program modules, and other functional divisions may be performed. Further, for the data storage unit, for example, a region in a storage device such as one hard disk may be used. Also, with respect to the processing flow, some steps can be executed at the same time or in a different order. For example, in FIG. 3, step S122 may be placed after step S119. Furthermore, step S114 may be executed immediately after step S100.

In addition, the description has been made using the tensor product type complex hypersurface or the tensor product type compound curved surface, but the same processing can be performed even if the projection transformation is performed, for example.
In the above description, the calibration and measurement processing using the hypersurface has been described as an example. However, the present invention is not necessarily limited to this, and other calibration methods of the lattice pattern projection method can be adopted. Furthermore, the above technical idea is not limited to the lattice pattern projection method, and can be applied to other measurement methods.

(Appendix 1)
A measurement method in a computer numerical control device capable of mounting a measuring instrument for measuring an object shape,
A calibration step for performing calibration of the measuring instrument in a state of being mounted on the computer numerical control device;
When a change in a predetermined state including remounting of the measuring instrument occurs, the measurement result by the measuring instrument for three or more reference positions is acquired without performing calibration again, and the measurement result is set to the reference position. A conversion data calculation step for calculating conversion data for conversion;
Measuring the object to be measured based on the calibration by the measuring instrument, and converting the measurement result by the conversion data;
Measuring method including

(Appendix 2)
In the conversion data calculation step,
The relative position of the reference object is moved by the computer numerical control device, and the predetermined position of the reference object after the movement is used as the reference position.
The object shape of the reference object after movement is measured by the measuring instrument, and the measurement result by the measuring instrument corresponding to a predetermined position of the reference object is acquired based on the measurement result. Measurement method.

(Appendix 3)
The measurement method according to appendix 1, wherein the change in the predetermined state includes detecting a temperature change or a time lapse exceeding a predetermined threshold.

(Appendix 4)
The measurement step includes
Performing measurement of the first portion of the object to be measured by the measuring instrument;
Moving the relative position of the object to be measured by the computer numerical control device;
Performing measurement of a second portion of the object to be measured after movement by the measuring instrument;
A synthesis step of moving the measurement result of the first part or the second part of the measurement object using the movement data of the measurement object, and combining the measurement result with another measurement result;
The measuring method of Additional remark 1 containing.

(Appendix 5)
In the synthesizing step, the measurement result of the first part or the second part of the object to be measured is moved by further using axis data relating to the rotation or tilt movement of the object executed by the computer numerical control device. The measuring method according to supplementary note 4, characterized by:

(Appendix 6)
After the calibration step,
The computer numerical control device rotates or tilts the reference object around a predetermined axis, and the measuring instrument measures the object shape of the reference object at three or more positions. Based on the measurement result, the predetermined reference object is determined. Identifying the position of
Calculating normal data of a plane including the predetermined position from the predetermined position of the identified reference object;
The measurement method according to appendix 5, further comprising:

(Appendix 7)
The measuring instrument is a grid pattern projection type measuring instrument having a projecting unit that projects a predetermined grid pattern onto a specific object and an imaging unit that captures the specific object,
The calibration step comprises
From the captured image of the projected lattice pattern projected onto the surface, which is the specific object, by the projecting means for each of a plurality of height surfaces realized by the computer numerical control device, A first set including a set of coordinates of the points in the vertical and horizontal numbers common to each of the light receiving surfaces of the photographing unit, the light intensity of the points, and the height is generated, and the first set is generated. Storing the data of the set in a storage device;
A second for converting the light intensity into a phase angle of the projection grating pattern, including a set of the coordinates of the point on the light receiving surface, the phase angle and the height, and forming a rectangular grid with each set as a node. Storing the set of data in a storage device;
The measurement method according to any one of appendices 1 to 6, including:

(Appendix 8)
A hypersurface generation step of generating data representing a tensor product type complex hypersurface from the data of the second set, and storing the data in a storage device;
The measurement method according to appendix 7, further including:

(Appendix 9)
The measurement method according to claim 8, wherein, in the hypersurface generation step, the control points of the tensor product type composite hypersurface are calculated using the data of the second set as input points.

(Appendix 10)
At the time of measurement by the measuring instrument in the conversion data calculation step and the measurement step,
A set of coordinates and light intensity on the light receiving surface of the photographing means is extracted from the photographed image of the projected grid pattern projected onto the measurement object by the projection means and photographed by the photographing means, and stored in a storage device. Storing, and
Converting the light intensity into a phase angle of the projected grating pattern, and storing data of a set of coordinates on the light receiving surface and the phase angle in a storage device;
Using the data representing the tensor product type complex hypersurface, an interpolation step is performed to interpolate and calculate height data corresponding to a set of coordinates and phase angle on the light receiving surface, and to store in a storage device;
The measurement method according to appendix 8, further comprising:

(Appendix 11)
In the calibration step,
The surface which is the specific object photographed by the photographing unit without projecting a lattice pattern by the projecting unit for each surface including a plurality of points having one or a plurality of heights and whose real coordinates are known. Generating a third set including a plurality of sets of coordinates on the light receiving surface of the imaging means, the actual coordinates of the points, and the height from the captured image of the imaging means, and storing the data of the third set in a storage device ,
The measurement method according to appendix 10, further comprising:

(Appendix 12)
A second hypersurface generation step of generating data representing a second tensor product type complex hypersurface from the third set and storing the data in a storage device;
The measurement method according to appendix 11, further comprising:

(Appendix 13)
A curved surface generation step of generating data representing a tensor product type complex curved surface using data other than the data of the height of each set of data included in the third set, and storing the data in a storage device;
The measurement method according to appendix 11, further comprising:

(Appendix 14)
Using the data representing the second tensor product type complex hypersurface, interpolation calculation is performed on real coordinate data corresponding to the set of height data generated in the interpolation step and the corresponding coordinate set on the light receiving surface, Storing in a storage device;
The measurement method according to appendix 12, further comprising:

(Appendix 15)
Using the data representing the tensor product type compound curved surface, interpolating the actual coordinate data before correction corresponding to the data of the corresponding coordinate on the light receiving surface, and storing in the storage device;
Correcting the actual coordinate data before correction based on the height data generated by the interpolation step and the height data at the time of calibration, and storing the corrected data in a storage device;
The measurement method according to appendix 13, further comprising:

(Appendix 16)
A measuring instrument for measuring the object shape;
A computer numerical controller capable of mounting the measuring device;
When a change in a predetermined state including remounting of the measuring instrument occurs after calibration of the measuring instrument is performed in the state of being mounted on the computer numerical control device, three or more reference positions are performed without performing calibration again. A conversion data calculation means for acquiring a measurement result by the measuring instrument and calculating conversion data for converting the measurement result to the reference position;
When measuring the measurement object based on the calibration by the measuring instrument, means for converting the measurement result by the conversion data;
Measuring system.

(Appendix 17)
A program for causing a measurement system including a measuring instrument for measuring an object and a computer numerical control device capable of mounting the measuring instrument to perform measurement,
When a change in a predetermined state including remounting of the measuring instrument occurs after calibration of the measuring instrument is performed in the state of being mounted on the computer numerical control device, three or more reference positions are performed without performing calibration again. A conversion data calculation step of acquiring a measurement result by the measuring instrument and calculating conversion data for converting the measurement result to the reference position;
When measuring the object to be measured based on the calibration by the measuring instrument, converting the measurement result by the conversion data;
A program for running

It is an apparatus block diagram in the lattice pattern projection method of a prior art. It is a functional block diagram of a CNC device including a measuring unit according to an embodiment of the present invention. It is a figure which shows an example of the processing flow which concerns on one embodiment of this invention. It is a figure which shows an example of the processing flow of a calibration process. (A) is a schematic diagram for demonstrating projection and imaging | photography of a lattice pattern. (B) And (c) is a figure which shows the example of an image of an imaging result. It is a figure which shows an example of the data stored in a calibration data storage part. It is a schematic diagram showing the structure of the input point used as the basis which produces | generates the control point of a tensor product type complex hypersurface. It is a figure which shows an example of the processing flow of a control point production | generation process. It is a figure which shows an example of the data stored in a calibration data storage part. (A) And (b) is a figure for demonstrating the production | generation process of the control point in a Bezier curve. It is a figure for demonstrating the production | generation process of the control point in a B-Spline curve. (A) thru | or (c) are figures which show an example of a real lattice pattern. It is a figure which shows an example of the data stored in a calibration data storage part. (A) And (b) is a figure which shows an example of the data stored in a calibration data storage part. It is a schematic diagram for demonstrating the synthesis | combination of measurement data. (A) And (b) is a schematic diagram for demonstrating the problem at the time of the reattachment of a measurement part. It is a figure which shows an example of the processing flow at the time of a measurement process. It is a figure which shows an example of the data stored in a measurement data storage part. It is a schematic diagram for demonstrating the synthesis | combination of measurement data. It is a figure which shows an example of the 2nd processing flow at the time of the calibration process for the measurement of X coordinate and Y coordinate. It is a figure which shows an example of the 2nd processing flow at the time of the measurement process of X coordinate and Y coordinate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid crystal projector 2 Reference plane 4 Camera 5 Image processing apparatus 6 Movement control part 7 Temperature sensor 11 Projection part 12 Liquid crystal panel 13 Lens 41 Lens 42 CCD 51 Camera control part 52 Projection control part 53 Calibration process part 54 CNC data setting part 55 Control point generation unit 56 Real coordinate calculation unit 57 Calibration data storage unit 58 Measurement data storage unit 59 Synthesis processing unit 60 Correction processing unit 61 Synthesis data storage unit 62 Correction data storage unit 500 Main control unit

Claims (5)

A measurement method in a computer numerical control device capable of mounting a measuring instrument for measuring an object shape,
A calibration step for performing calibration of the measuring instrument in a state of being mounted on the computer numerical control device;
If the variation of the predetermined conditions including remounting of the instrument has occurred, acquires a measurement result of the measuring instrument for three or more reference positions, calculates the conversion data to convert the measurement results into the reference position Conversion data calculation step to perform,
A measurement step of measuring an object to be measured based on the calibration by the measuring instrument, and converting the measurement result by the conversion data;
Only including,
The measuring instrument is a grid pattern projection type measuring instrument having a projecting unit that projects a predetermined grid pattern onto a specific object and an imaging unit that captures the specific object,
The calibration step comprises
From the captured image of the projected lattice pattern projected onto the surface, which is the specific object, by the projecting means for each of a plurality of height surfaces realized by the computer numerical control device, A first set including a set of coordinates of the points in the vertical and horizontal numbers common to each of the light receiving surfaces of the photographing unit, the light intensity of the points, and the height is generated, and the first set is generated. Storing the data of the set in a storage device;
A second for converting the light intensity into a phase angle of the projection grating pattern, including a set of the coordinates of the point on the light receiving surface, the phase angle and the height, and forming a rectangular grid with each set as a node. Storing the set of data in the storage device;
Generating data representing a tensor product type complex hypersurface from the data of the second set, and storing the data in the storage device;
Including
At the time of measurement by the measuring instrument in the conversion data calculation step and the measurement step,
Extracting data of a set of coordinates and light intensity on the light receiving surface of the photographing means from a photographed image of the projected grid pattern projected by the projecting means on the object to be measured and photographed by the photographing means, An extraction step for storing in a storage device;
Converting the light intensity extracted in the extraction step into a phase angle of the projection grating pattern and storing data of a set of coordinates and the phase angle on the light receiving surface in the storage device;
Using the data representing the tensor product type complex hypersurface, interpolation calculation is performed for the height data corresponding to the data of the set of coordinates and the phase angle on the light receiving surface, and stored in the storage device;
Measuring method including In the conversion data calculation step,
The relative position of the reference object is moved by the computer numerical control device, and the predetermined position of the reference object after the movement is used as the reference position.
The object shape of the reference object after movement is measured by the measuring instrument, and a measurement result by the measuring instrument corresponding to a predetermined position of the reference object is acquired based on the measurement result. The measurement method described.   The measurement method according to claim 1, wherein the change in the predetermined state includes detecting a temperature change or a time lapse exceeding a predetermined threshold. A measuring instrument for measuring the object shape;
A computer numerical controller capable of mounting the measuring device;
Calibration means for performing calibration of the measuring instrument;
If the variation of the predetermined conditions including remounting of the instrument after performing by said calibration means to calibrate the instrument in a state mounted on the computer numerical control device has occurred, the measuring instrument for three or more reference positions Conversion data calculation means for acquiring the measurement result by and calculating conversion data for converting the measurement result to the reference position;
When measuring the measurement object based on the calibration by the measuring instrument, means for converting the measurement result by the conversion data;
I have a,
The measuring instrument is a grid pattern projection type measuring instrument having a projecting unit that projects a predetermined grid pattern onto a specific object and an imaging unit that captures the specific object,
The calibration means is
From the captured image of the projected lattice pattern projected onto the surface, which is the specific object, by the projecting means for each of a plurality of height surfaces realized by the computer numerical control device, A first set including a set of coordinates of the points in the vertical and horizontal numbers common to each of the light receiving surfaces of the photographing unit, the light intensity of the points, and the height is generated, and the first set is generated. Store the data of the set in a storage device,
A second for converting the light intensity into a phase angle of the projection grating pattern, including a set of the coordinates of the point on the light receiving surface, the phase angle and the height, and forming a rectangular grid with each set as a node. Storing the set of data in the storage device,
Data representing a tensor product type complex hypersurface is generated from the data of the second set, and stored in the storage device.
The instrument is
Extracting data of a set of coordinates and light intensity on the light receiving surface of the photographing means from the photographed image of the projection grid pattern projected by the projecting means on the object to be measured and photographed by the photographing means, Storing in the storage device;
The extracted light intensity is converted into a phase angle of the projection grating pattern, and data of a set of coordinates and the phase angle on the light receiving surface is stored in the storage device,
Using data representing the tensor product type complex hypersurface, interpolation calculation of height data corresponding to data of a set of coordinates and the phase angle on the light receiving surface, and storing in the storage device,
Measuring system. A program for causing a measurement system including a measuring instrument for measuring an object and a computer numerical control device capable of mounting the measuring instrument to perform measurement,
If the variation of the predetermined conditions including remounting of the instrument after performing calibration of the instrument in a state mounted on the computer numerical control device has occurred, the measurement result of the measuring instrument for three or more reference positions A conversion data calculation step for acquiring and calculating conversion data for converting the measurement result to the reference position;
When measuring the measurement object based on the calibration by the measuring instrument, a measurement step of converting the measurement result by the conversion data,
Was executed,
The measuring instrument is a grid pattern projection type measuring instrument having a projecting unit that projects a predetermined grid pattern onto a specific object and an imaging unit that captures the specific object,
Calibration of the instrument is
From the captured image of the projected lattice pattern projected onto the surface, which is the specific object, by the projecting means for each of a plurality of height surfaces realized by the computer numerical control device, A first set including a set of coordinates of the points in the vertical and horizontal numbers common to each of the light receiving surfaces of the photographing unit, the light intensity of the points, and the height is generated, and the first set is generated. A process of storing the data of the set in a storage device;
A second for converting the light intensity into a phase angle of the projection grating pattern, including a set of the coordinates of the point on the light receiving surface, the phase angle and the height, and forming a rectangular grid with each set as a node. Storing the data of the set in the storage device;
Generating data representing a tensor product type complex hypersurface from the data of the second set, and storing the hypersurface in the storage device;
Including
At the time of measurement by the measuring instrument in the conversion data calculation step and the measurement step,
Extracting data of a set of coordinates and light intensity on the light receiving surface of the photographing means from a photographed image of the projected grid pattern projected by the projecting means on the object to be measured and photographed by the photographing means, An extraction step for storing in a storage device;
Converting the light intensity extracted in the extraction step into a phase angle of the projection grating pattern and storing data of a set of coordinates and the phase angle on the light receiving surface in the storage device;
Using the data representing the tensor product type complex hypersurface, interpolation calculation is performed for the height data corresponding to the data of the set of coordinates and the phase angle on the light receiving surface, and stored in the storage device;
A program for running

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