JP2016224035A - Measurement device, system, article manufacturing method, calculation method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a measurement device advantageous for high-precision measurement of a shape of a to-be-measured object.SOLUTION: A measurement device for measuring a shape of a to-be-measure object, comprises a processing unit that obtains information on the shape of the to-be-measured object on the basis of an image obtained by imaging the to-be-measured object onto which pattern light that alternately contains bright parts and dark parts along a first direction is projected. The processing unit acquires, from regions of the image corresponding to the dark parts, a plurality of first signals different from each other indicating a light intensity distribution in a second direction orthogonal to the first direction, obtains an evaluation value for a quality of each of a plurality of correction signals each obtained by correcting second signals representing a light intensity distribution in the second direction acquired from regions of the image corresponding to the bright parts using the plurality of first signals, respectively, and obtains the information using the correction signal having the evaluation value within an allowable range.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a measuring apparatus, system, article manufacturing method, calculation method, and program for measuring the shape of an object to be measured.

  3D coordinates are projected from the principle of triangulation based on the position of the reflected light obtained by projecting the line pattern light represented by the spatial coding method onto the object to be measured through a projection unit such as a projector. There are known measuring devices for obtaining the above. In such a measuring apparatus, the measurement result tends to be easily influenced by the material of the object to be measured.

  For example, in the field of industrial production, a resin may be handled as an object to be measured. When the object to be measured is a resin, it is known that light projected onto the object to be measured enters the object to be measured and is scattered inside the object to be measured, so-called internal scattering. When internal scattering occurs, the reflected light from the object to be measured includes internal scattered light from the inside of the object to be measured in addition to the surface scattered light from the surface of the object to be measured. Since the internally scattered light includes scattered light from a different distance from the surface scattered light, the measurement device calculates a measurement value different from the surface position of the object to be measured. Accordingly, the internally scattered light appears as a systematic error in the measuring apparatus and becomes a factor that decreases the measurement accuracy.

  Therefore, a technique for reducing the influence of internal scattering has been proposed (see Non-Patent Document 1). In such a technique, a bright portion and a dark portion are included, and spatially high-frequency pattern light is projected onto a resin that is an object to be measured, and an internal scattering is obtained from an intensity distribution in a bright portion including a surface scattering component and an internal scattering component The intensity distribution in the dark part including the component is subtracted. As described above, in Non-Patent Document 1, by reducing the internal scattering component from the intensity distribution in the bright part, an error (systematic error) in which the three-dimensional coordinates obtained by the measurement device are systematically shifted in the internal direction of the measurement object. ) Can be reduced.

S.K.Nayer et al. Fast separation of Direct and Global Components ofa Scene using High Frequency Illumination. SIGGRAPH Jul, 2006.

  However, Non-Patent Document 1 does not specifically disclose the relationship between the spatial frequency of pattern light and internal scattering or surface scattering. For example, when the spatial frequency of the pattern light is low, the internal scattering component is not included in the intensity distribution in the dark part, and thus the internal scattering component included in the intensity distribution in the bright part cannot be appropriately removed. . On the other hand, when the spatial frequency of the pattern light is high, considering the optical point image intensity distribution including defocus, the bright part spreads spatially, so that the surface scattering component is included in the intensity distribution in the dark part. included. Therefore, if the intensity distribution in the dark part is subtracted from the intensity distribution in the bright part, the surface scattering component is also subtracted from the intensity distribution in the bright part, so that the internal scattering component cannot be appropriately removed. As described above, in Non-Patent Document 1, it is not always possible to optimally reduce the influence of internal scattering on the object to be measured, that is, the systematic error that is a factor that reduces the measurement accuracy of the measurement apparatus.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide a measurement device that is advantageous for measuring the shape of an object to be measured with high accuracy.

  In order to achieve the above object, a measuring device according to one aspect of the present invention is a measuring device that measures the shape of an object to be measured, and includes pattern light that alternately includes bright and dark portions along a first direction. Based on an image obtained by imaging the object to be measured, and a processing unit for obtaining information on the shape of the object to be measured, and the processing unit from the region of the image corresponding to the dark part The light intensity in the second direction obtained from a plurality of different first signals indicating the light intensity distribution in the second direction intersecting the first direction and obtained from the region of the image corresponding to the bright portion An evaluation value for each pass / fail of each of the plurality of correction signals obtained by correcting the second signal representing the distribution using each of the plurality of first signals is obtained, and the evaluation value falls within an allowable range. The information is obtained using a correction signal. And wherein the Rukoto.

  Further objects and other aspects of the present invention will become apparent from the preferred embodiments described below with reference to the accompanying drawings.

  According to the present invention, for example, a measuring apparatus that is advantageous for measuring the shape of an object to be measured with high accuracy is provided.

It is the schematic which shows the structure of the measuring device as 1 side surface of this invention. It is a figure which shows an example of the pattern light produced | generated by the mask of the measuring device shown in FIG. It is a figure which shows an example of the image acquired by imaging pattern light. It is a figure which shows an example of the intensity distribution acquired from the bright part of the image shown in FIG. It is a figure which shows an example of the measurement signal in a bright part, the surface scattering signal in a bright part, the internal scattering signal in a bright part, and the measurement signal in a dark part. It is a figure which shows an example of the measurement signal in a bright part, the surface scattering signal in a bright part, the internal scattering signal in a bright part, and the measurement signal in a dark part. It is a figure which shows an example of the measurement signal in a bright part, the surface scattering signal in a bright part, the internal scattering signal in a bright part, and the measurement signal in a dark part. It is a figure which shows the relationship between the length of the Y-axis direction of a dark part, the systematic error contained in a correction signal, and the symmetry of a correction signal. It is a figure which shows the relationship between the length of the Y-axis direction of a dark part, the systematic error contained in a correction signal, and the symmetry of a correction signal. It is a figure which shows the relationship between the length of the Y-axis direction of a dark part, the systematic error contained in a correction signal, and the symmetry of a correction signal. It is a flowchart for demonstrating the measurement process in the measuring device shown in FIG. It is a flowchart for demonstrating the measurement process in the measuring device shown in FIG. It is a figure for demonstrating the intensity distribution in the imaging surface of the light reflected by the to-be-measured object. It is a figure which shows the system containing a measuring device and a robot.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the accompanying drawings. In addition, in each figure, the same reference number is attached | subjected about the same member and the overlapping description is abbreviate | omitted.

  FIG. 1 is a schematic diagram showing a configuration of a measuring apparatus 100 as one aspect of the present invention. The measuring device 100 measures the shape of the measurement object 5 based on the principle of triangulation. As shown in FIG. 1, the measurement apparatus 100 includes a projection unit 1, an imaging unit 3, and a processing unit 4. The measuring apparatus 100 projects the light encoded from the projection unit 1, that is, the pattern light onto the measurement object 5, and captures the pattern light with the imaging unit 3 from the image acquired by the processing unit 4. Three-dimensional coordinate point group data (information on the shape of the measurement object 5) of the measurement object 5 is obtained. Further, the processing unit 4 has a function of obtaining the position or orientation of the measurement object 5 by fitting three-dimensional coordinate point group data to a CAD model of the measurement object 5 registered in advance.

  Here, with reference to FIG. 13, in a general measuring apparatus that measures the shape of an object to be measured based on the principle of triangulation, a system error that occurs when the object to be measured is resin will be described. When the object to be measured is a resin, the surface scattering light from the surface of the object to be measured and the internal scattered light from the inside of the object to be measured are imaged on the imaging unit (on the imaging surface), so the influence of internal scattering Therefore, systematic errors are included in the measurement results.

  FIG. 13 is a diagram for explaining the intensity distribution (light intensity distribution) on the imaging surface of the light reflected from the measurement object by projecting light from the projection unit onto the measurement object. Here, as an explanation of the reflected light from the object to be measured causing internal scattering being imaged on the imaging surface, the inside of the object to be measured is considered to be a multilayer structure, and the scattered light from each layer is imaged on the imaging surface. A model to be described will be described as an example.

  FIG. 13 shows a state in which light projected onto the measurement object along the optical axis of the projection unit is scattered and spread inside the measurement object. When light is reflected only on the surface of the object to be measured, that is, in the case of an object to be measured that does not cause internal scattering, for example, when light is projected on the object to be collected with a Gaussian distribution, the imaging surface The intensity distribution above is a symmetric intensity distribution. On the other hand, in the case of an object to be measured that causes internal scattering, as shown in FIG. 13, the scattered light from the surface of the object to be measured and each layer inside the object to be measured, that is, the first layer, the second layer, and the third layer. Are superimposed and imaged on the imaging surface. Therefore, when the reflected light from the surface of the object to be measured is strong and the reflected light due to internal scattering gradually weakens in each layer, the intensity distribution on the imaging surface is an asymmetric intensity distribution.

  Consider that the intensity distribution on the imaging surface is classified into surface scattering and internal scattering from the object to be measured. In the surface scattering, the light collected on the surface of the object to be measured is reflected and imaged on the imaging surface, so that the intensity distribution (width) on the imaging surface becomes narrow. On the other hand, in the internal scattering, there is a spread of light due to the internal scattering (that is, light is not condensed on each layer of the object to be measured), so that the intensity distribution on the imaging surface is widened. In addition, in the internal scattering, since the scattered light of the light entering the object to be measured is acquired on the imaging surface, the internal scattering peak appears at a position different from the surface scattering peak on the imaging surface. .

  For example, as shown in FIG. 13, the imaging position of the scattered light from each of the first layer, the second layer, and the third layer inside the object to be measured is from the surface of the object to be measured. The scattered light is gradually shifted from the imaging position on the imaging surface. Accordingly, since the light intensity distribution due to internal scattering and the light intensity distribution due to surface scattering are superimposed on the imaging surface, an asymmetric intensity distribution is obtained.

  On the other hand, when only surface scattering occurs, the intensity distribution obtained on the imaging surface is only the light intensity distribution due to surface scattering. The shape can be determined accurately. However, when internal scattering occurs, if the center of gravity is simply detected for an asymmetric intensity distribution, the shape of the position drawn into the object to be measured is required due to the asymmetry of the intensity distribution. . As described above, when internal scattering occurs, an error that statistically shifts in the internal direction of the object to be measured, that is, a systematic error occurs, so that the shape of the object to be measured cannot be obtained accurately.

  Therefore, in the measurement apparatus 100 of the present embodiment, the influence (systematic error) of the asymmetric intensity distribution caused by internal scattering of the measurement object 5 such as resin is optimally reduced, and the shape of the measurement object 5 is highly accurate. Realize to measure. In the measurement apparatus 100, the pattern light projected onto the measurement object 5 includes bright portions and dark portions alternately along the first direction. And among the images acquired by imaging the pattern light projected on the measurement object 5, from the region corresponding to the dark part of the pattern light, the second direction intersecting the first direction (for example, with respect to the first direction). A plurality of different first signals indicating intensity distributions in a vertical direction). In addition, among the images acquired by imaging the pattern light projected on the measurement object 5, a plurality of second signals representing the intensity distribution in the second direction acquired from the area corresponding to the bright part of the pattern light are provided. A plurality of correction signals are obtained by correcting each of the first signals. Next, evaluation values for the quality of each of the plurality of correction signals are obtained, and information on the shape of the object to be measured 5 is obtained (calculated) using the correction signal that makes the evaluation values within an allowable range. This makes it possible to optimally reduce the influence of internal scattering from the intensity distribution in the bright part of the pattern light.

  Hereinafter, a specific configuration of the measuring apparatus 100 will be described in detail. The projection unit 1 includes a light source 8, an illumination optical system 9, a mask 10, and a projection optical system 11. The illumination optical system 9 is an optical system for uniformly illuminating the mask 10 with the light emitted from the light source 8, and for example, the mask 10 is Koehler illuminated. In the mask 10, for example, a transmissive region and a light-shielding region for generating a pattern to be projected onto the measurement object 5 are formed by sputtering and etching chromium on a glass substrate. The projection optical system 11 is an optical system for projecting the pattern of the mask 10 onto the measurement object 5.

  FIG. 2 is a diagram illustrating an example of the pattern light PL generated by the mask 10. In this embodiment, the mask 10 generates pattern light PL in which lines that alternately include bright portions PLa and dark portions PLb along the Y-axis direction (first direction) are periodically arranged in the X-axis direction. Functions as a generation unit. The pattern light PL including the bright part PLa and the dark part PLb that is projected onto the measurement object 5 is generated by the light passing through the transmission region of the mask 10 and the light shielded by the light shielding region of the mask 10. In the present embodiment, the pattern light PL includes a plurality of dark portions PLb having different lengths Ly in the Y-axis direction. The dark portion PLb of the pattern light PL functions as an identification portion for identifying the bright portion PLa, and the identification portion is composed of a plurality of dots. Thus, the pattern light PL is a plurality of dark portions PLb that are randomly arranged, that is, dot line pattern light obtained by encoding a pattern with dots. The encoded dot line pattern light realizes a function as a code for identifying which line each line included in the image acquired by the imaging unit 3 is.

  The imaging unit 3 includes an imaging optical system 6 and an imaging element 7 and images the pattern light PL projected on the measurement object 5 to acquire an image. The imaging optical system 6 is an optical system for forming an image on the imaging element 7 with the pattern light PL projected on the measurement object 5. The imaging element 7 is an image sensor for imaging the pattern light PL formed on the imaging surface and converting it into an image. The image sensor 7 includes, for example, a CMOS sensor or a CCD sensor.

  The processing unit 4 obtains information on the shape of the measurement object 5 based on the image acquired by the imaging unit 3. In this embodiment, the processing unit 4 associates each line included in the image acquired by the imaging unit 3 and performs processing for reducing the influence of internal scattering, and then, based on the principle of triangulation. Then, the three-dimensional coordinate point group data of the measurement object 5 is obtained.

  A measurement process for measuring the shape of the measurement object 5 in the measurement apparatus 100 will be described in detail. First, it will be described that there is an optimum length for minimizing the systematic error due to internal scattering for the length Ly of the dark portion PLb of the pattern light PL.

  FIG. 3 is a diagram illustrating an example of an image acquired by imaging the pattern light PL projected onto the resin as the measurement object 5. In the image shown in FIG. 3, the black portion is a region having a low intensity, and the white portion is a region having a high intensity. A portion where the intensity on X = 0 is maximized is a bright portion, and a portion where the intensity on X = 0 is minimized is a dark portion. FIG. 4 is a diagram illustrating an example of an intensity distribution in the X-axis direction (second direction orthogonal to the first direction) acquired from the bright portion illustrated in FIG. 3. The intensity distribution shown in FIG. 4 spreads to the negative side with respect to X = 0 due to the influence of internal scattering, and is asymmetrical in the X-axis direction.

  FIG. 5, FIG. 6 and FIG. 7 show the measurement signal in the bright part and the surface in the bright part when the length in the Y-axis direction of the dark part, which is the interval of the bright part on X = 0, is changed. It is a figure which shows an example of a scattering signal, the internal scattering signal in a bright part, and the measurement signal in a dark part. Here, the measurement signal at the bright portion is a signal (second signal) representing an intensity distribution in the X-axis direction acquired from the region corresponding to the bright portion, specifically, the central portion of the region in the Y-axis direction. It is. Similarly, the measurement signal in the dark part is a signal (first signal) representing the intensity distribution in the X-axis direction acquired from the area corresponding to the dark part, specifically, the central part of the area in the Y-axis direction. . The surface scattering signal in the bright part is a signal representing the intensity distribution in the X-axis direction of the surface scattered light in the region corresponding to the bright part, and the internal scattering signal in the bright part corresponds to the bright part. It is a signal showing the intensity distribution in the X-axis direction of the internally scattered light in the region to be used.

  Referring to FIG. 5 to FIG. 7, when the dark part has a specific length in the Y-axis direction, it is included in the correction signal obtained by correcting the measurement signal in the bright part using the measurement signal in the dark part. Explain that the systematic error is minimized. Here, it is assumed that the correction signal is acquired by taking the difference between the measurement signal in the bright part and the measurement signal in the dark part. In addition, it is assumed that the length of the dark portion in the Y-axis direction becomes longer in the order of FIG. 5, FIG. 6, and FIG. In other words, the length of the dark portion in the Y-axis direction is the smallest in FIG. 5, the length of the dark portion in the Y-axis direction is the longest in FIG. 7, and the length of the dark portion in the Y-axis direction is the longest in FIG. It is halfway between the smallest length and the longest length.

  Referring to FIG. 5, in the measurement signal in the dark part, the length of the dark part in the Y-axis direction is small, so that in addition to the internal scattering component in the dark part, it spreads spatially by the point image distribution in the bright part. Surface scattering components. Therefore, when the measurement signal in the dark part is subtracted from the measurement signal in the bright part, not only the internal scattering component but also the surface scattering component is subtracted from the measurement signal in the bright part (that is, only the internal scattering component cannot be removed). Therefore, a systematic error occurs.

  Further, referring to FIG. 7, the measurement signal in the dark part does not become larger than the internal scattering signal in the bright part. This is because the length of the dark portion in the Y-axis direction is long, so that the internally scattered light spreading spatially from the bright portion does not enter the central portion of the dark portion. Therefore, the correction signal obtained by subtracting the measurement signal in the dark portion from the measurement signal in the bright portion does not match the surface scattering signal in the bright portion.

  On the other hand, referring to FIG. 6, since the internal scattering signal in the bright part and the measurement signal in the dark part substantially coincide, it is possible to appropriately remove the internal scattering component from the measurement signal in the bright part. is there. FIG. 8 shows the relationship between the length of the dark portion in the Y-axis direction and the systematic error included in the correction signal obtained by taking the difference between the measurement signal in the bright portion and the measurement signal in the dark portion. Referring to FIG. 8, it can be seen that the systematic error included in the correction signal is minimized when the length of the dark portion in FIG. 6 in the Y-axis direction, that is, the dark portion has a length LyA in the Y-axis direction. .

  In this way, the internal scattering component is optimally removed from the measurement signal in the bright part by correcting the measurement signal in the bright part using the measurement signal in the dark part having a specific length in the Y-axis direction. Is possible. This is because when the measurement signal in the bright part is corrected using the measurement signal in the dark part, in order to remove the internal scattering component from the measurement signal in the bright part, the optimum length of the dark part in the Y-axis direction is Because it exists.

  Next, a method for selecting a measurement signal for optimally correcting the measurement signal in the bright part from the measurement signals in the dark part having different lengths in the Y-axis direction will be described. When the pattern light PL is projected onto the object to be measured 5 that does not cause internal scattering and only the surface scattered light is imaged on the imaging unit 3, the intensity distribution obtained by the imaging unit 3 is symmetric because there is no internal scattered light. Intensity distribution.

  In the present embodiment, the brightness of the image is measured using a measurement signal representing an intensity distribution in a region corresponding to a dark portion of an image acquired by imaging the pattern light PL projected on the measurement object 5 that causes internal scattering. Consider a case where an asymmetric measurement signal representing an intensity distribution in a region corresponding to a portion is corrected. As described above, if the measurement signal in the bright part is corrected using the measurement signal in the dark part having a specific length in the Y-axis direction, the correction signal substantially represents the intensity distribution of only the surface scattered light. Therefore, the signal represents a highly symmetrical intensity distribution. Therefore, the correction signal obtained by taking the difference between the measurement signal in the bright part and the measurement signal in the dark part is evaluated using the symmetry as an evaluation value (index).

  There are various evaluation methods for evaluating the symmetry of the signal (waveform). For example, the symmetry of the correction signal may be evaluated from the amount of deviation between the position of the center of gravity of the correction signal and the position where the correction signal is the maximum value, or the midpoint between the two positions where the half value of the maximum value of the correction signal is The symmetry may be evaluated from the amount of deviation between the position and the position where the correction signal becomes the maximum value. Further, in probability theory and statistics, the symmetry of the correction signal may be evaluated using the skewness (third-order moment) that is an index of asymmetry.

  FIG. 8 shows the relationship between the length of the dark part in the Y-axis direction and the symmetry of the correction signal obtained by taking the difference between the measurement signal in the bright part and the measurement signal in the dark part. Here, the amount of deviation between the position of the center of gravity of the correction signal and the position where the correction signal becomes the maximum value is used as an index of symmetry. Referring to FIG. 8, it can be seen that the symmetry of the correction signal is the highest when the measurement signal in the dark part that minimizes the systematic error included in the correction signal is used.

  FIG. 9 and FIG. 10 are diagrams illustrating the relationship between the length of the dark portion in the Y-axis direction, the systematic error included in the correction signal, and the symmetry of the correction signal, for the objects to be measured that cause different internal scattering. . Referring to FIGS. 9 and 10, as in FIG. 8, when the measurement signal in the dark part that minimizes the systematic error included in the correction signal is used, the symmetry of the correction signal becomes the highest. . Thus, the tendency for the symmetry of the correction signal to increase when the systematic error included in the correction signal is minimized does not depend on the type of the object to be measured. Therefore, by evaluating the symmetry of the correction signal, it is possible to select the measurement signal in the dark part for optimally correcting the measurement signal in the bright part.

With reference to FIG. 11, the measurement process in the measurement apparatus 100 is demonstrated. Such measurement processing is performed by the processing unit 4 controlling the respective units of the measurement apparatus 100 in an integrated manner. Note that when the measurement apparatus 100 is activated, an initialization process is performed. The initialization process includes a process of starting the projection unit 1 and the imaging unit 3, a process of setting various parameters such as calibration data of the projection unit 1 and the imaging unit 3, and the like.
The signal processing of the measurement processing is executed by the computer of the processing unit 4 reading out the program. Note that software and programs that implement the functions of the present embodiment are supplied to an information processing apparatus including one or more computers via a network or various storage media. The processing unit of the information processing apparatus reads the program recorded or stored in the recording medium or the storage medium, so that the program is executed. A plurality of computers at distant locations may perform various processes of the program by transmitting and receiving data to each other by wired or wireless communication. The processing unit of the information processing apparatus constitutes each means for executing each step.

  In step S1102, the pattern light PL is projected from the projection unit 1 onto the measurement object 5. In step S <b> 1104, the pattern light PL projected on the measurement object 5 is imaged by the imaging unit 3 to acquire an image.

  In S1106, a correction signal is acquired based on the image acquired in S1104. Specifically, first, a measurement signal (first signal) representing an intensity distribution in the X-axis direction from each of a plurality of regions of the image corresponding to the central portion in the Y-axis direction of each of the plurality of dark portions PLb of the pattern light PL. ) To get. Similarly, a measurement signal (second signal) representing the intensity distribution in the X-axis direction is acquired from the region of the image corresponding to the central portion in the Y-axis direction of one bright part PLa of the pattern light PL. And a several correction signal is acquired by taking the difference of the measurement signal in bright part PLa, and each of the several measurement signal in several dark part PLb.

  In S1108, the symmetry of each of the plurality of correction signals is obtained as an evaluation value for the quality of each of the plurality of correction signals acquired in S1106. As described above, the symmetry of the correction signal may be obtained from the amount of deviation between the position of the center of gravity of the correction signal and the position that is the maximum value of the correction signal, or two positions that are half the maximum value of the correction signal. Symmetry may be obtained from the amount of deviation between the midpoint position and the position where the correction signal becomes the maximum value.

  In S1110, based on the symmetry obtained in S1108, a correction signal whose symmetry is within an allowable range is selected. In this embodiment, the measurement signal in the dark part PLb corresponding to the correction signal having the highest symmetry is selected.

  In S1112, using the measurement signal in the dark part PLb selected in S1110, the measurement signal in each bright part PLa along the Y-axis direction is corrected to generate a correction signal. Specifically, for each of the plurality of measurement signals acquired from the plurality of regions of the image corresponding to the plurality of bright portions PLa of the pattern light PL, the difference from the measurement signal in the dark portion PLb selected in S1110 is taken. Thus, a correction signal is generated.

  In S1114, the three-dimensional coordinate point group data of the measurement object 5 is obtained using the correction signal generated in S1112.

  As described above, in the present embodiment, the measurement signal for optimally correcting the measurement signal in the bright portion PLa is selected and corrected from the measurement signals in the plurality of dark portions PLb having different lengths in the Y-axis direction. To do. Thereby, the influence of internal scattering can be reduced from the measurement signal in the bright part PLa. Therefore, the measuring apparatus 100 can measure the shape of the measurement object 5 with high accuracy.

In the present embodiment, measurement signals (first signals) are acquired from a plurality of regions of an image corresponding to each of a plurality of dark portions PLb having different lengths in the Y-axis direction. However, the present invention is not limited to this. It is not something. For example, as shown in FIG. 2, each of a plurality of regions of the image corresponding to a plurality of portions of the dark part PLb having different distances Dt _{1 to} Dt ₄ along the Y-axis direction from the end Eg in the Y-axis direction of the dark part PLb. A measurement signal (first signal) may be obtained from

  In FIG. 11, the measurement signal (first signal) in the dark portion PLb used for generating the correction signal is selected based on the measurement signal (second signal) in one bright portion PLa of the pattern light PL. ing. However, even in one bright part PLa, the intensity distribution in the X-axis direction, that is, the measurement signal may differ depending on the position in the Y-axis direction. In such a case, in order to optimally correct the measurement signal in the bright part PLa, the dark part PLb used to generate a correction signal for the measurement signal at each position in the Y-axis direction of the bright part PLa. It is necessary to select and correct the measurement signal.

  With reference to FIG. 12, the measurement process in the case where the measurement signals at the respective positions in the Y-axis direction of one bright portion PLa of the pattern light PL will be described. Note that S1202 and S1204 illustrated in FIG. 12 are the same as S1102 and S1104 illustrated in FIG. 11, and thus detailed description thereof is omitted here.

  In S1206, based on the image acquired in S1204, a correction signal for each position in the Y-axis direction of one bright part PLa is acquired. Specifically, a plurality of measurement signals (from each of a plurality of regions of the image corresponding to a plurality of portions of the bright portion PLa having different distances along the Y-axis direction from the end in the Y-axis direction of one bright portion PLa) 2nd signal) is acquired. Further, a measurement signal (first signal) representing the intensity distribution in the X-axis direction is acquired from each of the plurality of regions of the image corresponding to the central portion in the Y-axis direction of each of the plurality of dark portions PLb of the pattern light PL. Then, the difference between each of the plurality of measurement signals (second signal) at the plurality of positions in the Y-axis direction of the bright part PLa and the plurality of measurement signals (first signal) at each of the plurality of dark parts PLb is taken. Thus, a plurality of correction signals are obtained.

  In S1208, the symmetry of each of the plurality of correction signals is obtained as an evaluation value for the quality of each of the plurality of correction signals acquired in S1106.

  In S1210, for each position in the Y-axis direction of one bright portion PLa, a correction signal whose symmetry is within an allowable range is selected from the plurality of correction signals acquired in S1106 based on the symmetry obtained in S1208. . In the present embodiment, the correction signal having the highest symmetry is selected.

  In S1212, three-dimensional coordinate point group data of the measurement object 5 is obtained using the correction signal selected in S1210.

  As described above, in one bright part PLa, even when the measurement signal differs depending on each position in the Y-axis direction, the measurement signal in the dark part PLb that is optimum for the measurement signal (second signal) at each position. By correcting using (first signal), the influence of internal scattering can be reduced.

<Other embodiments>
The above-described measuring device is used in a state of being supported by a certain support member. In the present embodiment, as an example, as shown in FIG. 14, a control system that is provided and used in a robot arm 300 (gripping device) will be described. The measuring apparatus 100 projects and images pattern light on the measurement object 210 placed on the support base 350, and acquires an image. Then, the control unit of the measurement apparatus 100 or the control unit 310 that has acquired the image data from the control unit of the measurement apparatus 100 obtains the position and orientation of the measurement object 210 and controls the obtained position and orientation information. Acquired by the unit 310. Based on the position and orientation information, control unit 310 sends a drive command to robot arm 300 to control robot arm 300. The robot arm 300 holds the object to be measured 210 with a robot hand or the like (gripping unit) at the tip, and moves it such as translation or rotation. Further, by assembling the measurement object 210 into other parts by the robot arm 300, an article composed of a plurality of parts, for example, an electronic circuit board or a machine can be manufactured. Further, an article can be manufactured by processing (processing) the moved measurement object 210. The control unit 310 includes an arithmetic device such as a CPU and a storage device such as a memory. Note that a control unit that controls the robot may be provided outside the control unit 310. In addition, measurement data measured by the measurement apparatus 100 and an obtained image may be displayed on the display unit 320 such as a display.

  As mentioned above, although preferable embodiment of this invention was described, it cannot be overemphasized that this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

100: Measuring device 1: Projection unit 10: Mask 3: Imaging unit 4: Processing unit 5: Object to be measured

Claims (18)

A measuring device for measuring the shape of an object to be measured,
A processing unit for obtaining information on the shape of the measurement object based on an image obtained by imaging the measurement object on which the pattern light including alternating bright and dark portions is projected along the first direction; And
The processor is
Obtaining a plurality of first signals different from each other indicating a light intensity distribution in a second direction intersecting the first direction from a region of the image corresponding to the dark portion;
A plurality of correction signals obtained by correcting, using each of the plurality of first signals, a second signal representing the light intensity distribution in the second direction acquired from the region of the image corresponding to the bright portion. The evaluation value about each quality is obtained,
The measurement apparatus characterized in that the information is obtained using a correction signal that makes the evaluation value within an allowable range. The pattern light includes a plurality of dark portions having different lengths in the first direction,
The measurement apparatus according to claim 1, wherein the processing unit acquires the plurality of first signals from each of a plurality of regions of the image corresponding to the plurality of dark portions.   The said process part acquires the said some 1st signal from each of the some area | region of the said image corresponding to the center part in the said 1st direction of each of these several dark parts. Measuring device.   The processing unit includes the plurality of first signals from each of the plurality of regions of the image corresponding to the plurality of portions of the dark part that are different from each other in the first direction from the end of the dark part in the first direction. The measurement apparatus according to claim 1, wherein The pattern light includes a plurality of bright portions along the first direction,
The processor is
The plurality of correction signals are acquired by taking a difference between each of the plurality of first signals and the second signal acquired from the image area corresponding to one of the plurality of bright portions. And
Selecting a first signal corresponding to the correction signal having the highest evaluation value from the plurality of correction signals;
For each of a plurality of second signals acquired from a plurality of regions of the image corresponding to the plurality of bright portions, a difference between the second signal and the first signal corresponding to the correction signal having the highest evaluation value is calculated. 5. The measuring apparatus according to claim 1, wherein a correction signal for obtaining the evaluation value within the allowable range is acquired.   The measurement apparatus according to claim 5, wherein the processing unit acquires the second signal from a region of the image corresponding to a central portion in the first direction of the one bright portion. The processor is
A plurality of second signals acquired from each of a plurality of regions of the image corresponding to a plurality of portions of the bright portion having different distances along the first direction from an end of the bright portion in the first direction; Obtaining the plurality of correction signals by taking the difference between each and the plurality of first signals,
2. The correction signal having the highest evaluation value from the plurality of correction signals is acquired as a correction signal for which the evaluation value is within the allowable range for each of the plurality of bright portions. 5. The measuring device according to any one of 4 to 4.   The measurement apparatus according to claim 1, wherein the dark part constitutes an identification part for identifying a line including the bright part in the pattern light.   The measuring device according to claim 8, wherein the identification unit includes a plurality of dots.   The measurement apparatus according to claim 1, wherein the evaluation value includes a value indicating symmetry of each waveform of the plurality of correction signals. A measuring device for measuring the shape of an object to be measured,
A processing unit for obtaining information on the shape of the measurement object based on an image obtained by imaging the measurement object on which the pattern light including alternating bright and dark portions is projected along the first direction; And
The pattern light includes a plurality of dark portions having different lengths in the first direction,
The processor is
Obtaining a plurality of different first signals indicating intensity distributions in a second direction intersecting the first direction from a plurality of regions of the image corresponding to the plurality of dark portions;
A measurement apparatus characterized by correcting the second signal representing the light intensity distribution in the second direction acquired from the image area corresponding to the bright portion using the first signal to obtain the information. .   The processing unit obtains the information by correcting a second signal representing an intensity distribution in the second direction acquired from the region of the image corresponding to the bright portion with the first signal. The measuring device according to claim 11. A projection unit that projects the pattern light onto the measurement object;
An image capturing unit that captures an image by capturing the object to be measured on which the pattern light is projected, and
The measurement apparatus according to claim 1, wherein the processing unit obtains information on a shape of the object to be measured based on an image acquired by the imaging unit. The measuring device according to any one of claims 1 to 13, which measures an object to be measured;
Based on the measurement result by the measurement device, a robot that holds and moves the object to be measured;
The system characterized by having. A step of measuring an object to be measured using the measuring device according to any one of claims 1 to 13,
And a step of manufacturing the article by processing the object to be measured based on the measurement result of the measuring device. A calculation method for calculating the shape of an object to be measured,
Obtaining an image obtained by imaging the object to be measured on which pattern light alternately including a bright part and a dark part is projected along the first direction;
Obtaining information on the shape of the object to be measured based on the image,
In the step of obtaining the information,
Obtaining a plurality of first signals different from each other indicating a light intensity distribution in a second direction intersecting the first direction from a region of the image corresponding to the dark portion;
A plurality of correction signals obtained by correcting, using each of the plurality of first signals, a second signal representing the light intensity distribution in the second direction acquired from the region of the image corresponding to the bright portion. The evaluation value about each quality is obtained,
A calculation method characterized in that the information is obtained by using a correction signal that makes the evaluation value within an allowable range. A calculation method for calculating the shape of an object to be measured,
Obtaining an image obtained by imaging the object to be measured on which pattern light alternately including a bright part and a dark part is projected along the first direction;
Obtaining information on the shape of the object to be measured based on the image,
The pattern light includes a plurality of dark portions having different lengths in the first direction,
In the step of obtaining the information,
Obtaining a plurality of different first signals indicating intensity distributions in a second direction intersecting the first direction from a plurality of regions of the image corresponding to the plurality of dark portions;
A calculation method comprising: correcting the second signal representing the light intensity distribution in the second direction acquired from the area of the image corresponding to the bright portion using the first signal to obtain the information. .   A program for causing an information processing apparatus to execute the calculation method according to claim 16 or 17.