JP2008180646A - Shape measuring device and shape measuring technique - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shape measuring device and a shape measuring technique capable of eliminating more effectively impact of reflected light due to secondary reflection. <P>SOLUTION: Laser beam is emitted to a measured object from a laser light source 12 and the reflected light at irradiation parts is received in optical receiving domain of a plurality of image sensors 24 and 26. The image sensors 24 and 26 output the optical receiving signal indicating amount of light received, which is in turn converted to digital data at drive circuits 42 and 44 to input into optical receiving position detecting sections 46a and 48a, and the optical receiving position detecting sections 46a and 48a detect optical receiving position with the peak value of amount of received light from optical receiving signal, to output it into distance calculating sections 46b and 48b. The distance calculation sections 46b and 48b calculate an estimate of inter-irradiation distance from the optical receiving position. When a plurality of estimates of inter-irradiation distance are computed at this time, while comparing those plurality estimates of inter-irradiation distance, values which agree each other within a predetermined allowable range are chosen as a formal inter-irradiation distance. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a shape measuring apparatus and a shape measuring method for irradiating a measurement target with laser light, detecting reflected light from the measurement target with a light receiving sensor, and measuring the shape of the measurement target based on the principle of triangulation. The present invention relates to a shape measuring apparatus and a shape measuring method capable of effectively excluding the influence of secondary reflection occurring on a measurement object.

  Laser light is irradiated to the measurement object, reflected light from the measurement object is detected by the light receiving sensor, and the external shape of the measurement object and the shape formed on the measurement object surface (for example, engraved characters, etc.) according to the principle of triangulation 2. Description of the Related Art A shape measuring device that measures a shape) is known. In this shape measuring device, the laser light irradiation site of the measurement target from the laser light source based on the position (light reception position) where the reflected light (part of the scattered light) of the laser light irradiated to the measurement target is received by the light receiving sensor This is a mechanism to calculate the three-dimensional coordinates of the laser light irradiation part by detecting the position vector that is the irradiation direction of the laser light and calculating the distance to the laser beam. Is reflected at another position (hereinafter referred to as secondary reflection), the secondary reflected light may be received by the light receiving sensor. Thus, when not only regular reflected light but also secondary reflected light is received by the light receiving sensor, a measurement error occurs due to the influence of the secondary reflected light.

For this reason, a shape measuring apparatus that excludes the influence of reflected light due to secondary reflection has been devised. For example, in Patent Document 1, when measuring the shape of a measurement object having a complicated shape such as a tooth model, the influences of secondary reflection on two light receiving sensors are contradictory (secondary reflection on one light receiving sensor). Is arranged so that the influence of the secondary reflection of the other light receiving sensor is small), and the area affected by the secondary reflection (this area is referred to as a multiple reflection area in Patent Document 1). When irradiating with laser light, the irradiation position of the laser light calculated from the light receiving position of the reflected light received by the two light receiving sensors is close to the coordinate axis origin set inside the measurement object. When the laser beam is selected as the position and the laser beam is irradiated outside the multiple reflection area, the laser beam received by the light receiving sensor with the larger light receiving signal output received by the two light receiving sensors. It means for selecting the irradiation position as the irradiation point of the normal is described.
JP 2004-257803 A

  According to the method described in Patent Document 1, it is considered that the tooth model and the like shown in the publication can exclude the influence of secondary reflection, but the inventor has various shapes and shapes of objects of materials. In the region affected by secondary reflection, there are two cases, the case where the regular reflection position is closer to the origin of the coordinate axis and the case farther from the origin of the coordinate axis, depending on the shape and material. Although the method described in Document 1 can be applied to shape measurement of a specific shape or material, it cannot be used for shape measurement of various shapes or materials. When measuring characters, symbols, and design shapes engraved on metal, there are two cases, the case where the normal reflection position is near the coordinate axis origin and the case far from the coordinate axis origin in the same measurement object. Therefore, the method described in Patent Document 1 cannot be applied.

  The present invention has been made in view of the above problems, and its purpose is to more effectively eliminate the influence of reflected light due to secondary reflection in the measurement of three-dimensional shapes of objects of various shapes and materials. And a shape measuring method are provided.

  In order to achieve the above object, the present invention is characterized by a laser beam irradiation device that irradiates a measurement target while scanning the laser beam, and a light receiving region, and a laser beam irradiated to the measurement target from the laser beam irradiation device. A plurality of light receiving sensors for receiving reflected light in the light receiving region and outputting a light receiving signal indicating the amount of light received in the light receiving region, and a shape of the measurement object based on the light receiving signals output from the plurality of light receiving sensors Data processing means for calculating shape data, wherein the data processing means receives light reception signals from the plurality of light receiving sensors, and determines the position in the light receiving area based on the received light reception signals. A light receiving position detecting means for detecting the light receiving position where the light receiving amount reaches a peak for each light receiving sensor, and a light receiving position detected by the light receiving position detecting means for each light receiving sensor. A distance calculating unit that calculates an estimated value of an inter-irradiation distance, which is a distance between the laser beam irradiation device corresponding to the laser beam irradiation site on the measurement target, for each light receiving position; and A normal distance selection unit that compares the estimated values of the inter-irradiation distances calculated for each of them and selects the estimated values of the inter-irradiation distances that match within a predetermined allowable range as normal inter-irradiation distances; There is to do.

  In this case, when the light receiving position detecting unit detects a plurality of light receiving positions from at least one light receiving signal, the normal distance selecting unit is configured to detect a plurality of light detected from the one light receiving signal calculated by the distance calculating unit. A plurality of estimated values of inter-irradiation distances corresponding to the light-receiving positions of the light-receiving positions are compared with estimated values of inter-irradiation distances corresponding to the light-receiving positions detected from other light-receiving signals calculated by the distance calculating means It is preferable to select an estimated value of the inter-irradiation distance that is the same as the inter-irradiation distance.

  According to the above-described shape measuring apparatus of the present invention, the laser light is irradiated from the laser light irradiation device onto the measurement target, and the reflected light at the irradiated portion is received by the light receiving regions of the plurality of light receiving sensors. The light receiving sensor outputs a light receiving signal representing the amount of light received in the light receiving region to the light receiving position detecting means, and the light receiving position detecting means detects the light receiving position where the peak value of the light receiving amount exists from the received light receiving signal.

  In this case, if secondary reflection occurs when the laser beam is irradiated from the laser beam irradiation device, the light receiving position detecting means detects a plurality of light receiving positions from the light receiving signal obtained from at least one light receiving sensor. There is a case. When a plurality of light receiving positions are detected, it is not possible to determine which light receiving position is the position where the regular reflected light (primary reflected light) is received. Therefore, in the shape measuring apparatus of the present invention, a distance calculating means and a normal distance selecting means are provided so that the light receiving position of the normal reflected light can be determined.

  In the present invention, by the distance calculation means, a laser beam irradiation device (more specifically, a laser light source in the laser beam irradiation device) and a portion (a laser beam emitted from the laser beam irradiation device is irradiated onto the surface of the measurement target ( An estimated value of the distance to the (irradiated part) (this distance is referred to as “inter-irradiation distance” in this specification) is calculated. The inter-irradiation distance can be determined based on the principle of triangulation from the position (light receiving position) at which the light receiving sensor receives the reflected light at the irradiated region within the light receiving region. However, if the received light is regular reflected light (primary reflected light), an accurate inter-irradiation distance can be obtained, but if it is secondary reflected light, a correct inter-irradiation distance cannot be obtained.

  In addition, when regular reflected light (primary reflected light) at a certain irradiation site is received by a plurality of light receiving sensors provided at different positions, the distances between the irradiations obtained from the light receiving positions of the respective light receiving sensors are substantially equal. Become. However, when secondary reflected light at a certain irradiation site is received by a plurality of light receiving sensors arranged at different positions, the distance between irradiations determined from the light receiving positions of the respective light receiving sensors is almost always different. In particular, when the two light receiving sensors are arranged symmetrically with respect to the laser light source in the plane perpendicular to the optical axis of the laser light emitted from the laser light irradiation device, the secondary reflection in each light receiving sensor. The distance between irradiations determined from the light receiving position is greatly different.

  For this reason, in the present invention, when the distance calculating means calculates the estimated values of the plurality of inter-irradiation distances, the normal distance selecting means compares the estimated values of the plurality of inter-irradiation distances to obtain a predetermined tolerance. The estimated inter-irradiation distance that matches within the range is selected as the normal inter-irradiation distance. Specifically, when a plurality of light receiving positions are detected from a light receiving signal output from one light receiving sensor, the normal distance selecting unit sets the plurality of light receiving positions output from the light receiving sensor calculated by the distance calculating unit. One or a plurality of inter-irradiation distances corresponding to one or a plurality of light receiving positions detected from a corresponding estimated value of a plurality of inter-irradiation distances and a light receiving signal output from another light receiving sensor calculated by the distance calculating means Are compared with the estimated value, and those that match within a predetermined allowable range are selected as normal inter-irradiation distances. The light receiving position corresponding to the selected regular inter-irradiation distance can be determined as the light receiving position where the regular reflected light is received.

  Thus, according to the present invention, when a plurality of light receiving positions are detected, the estimated values of the distances between the irradiations indicated by the light receiving positions are compared, and the estimated values of the distances between the irradiations that are substantially the same are compared with the normal distances between the irradiations. Have selected as. Since the light receiving position corresponding to the selected inter-irradiation distance is estimated to be the position where the primary reflected light that is not affected by the secondary reflection is received, the shape of the measurement object is determined based on the selected regular inter-irradiation distance. Accurately representing shape data can be created.

  The light receiving sensor applied to the present invention has a light receiving area, and when a certain pixel (pixel) in the light receiving area is irradiated with light, the pixel outputs a signal (light receiving signal) corresponding to the amount of received light. For example, a line sensor in which light receiving elements such as CCDs are arranged in a row, or an area sensor in which a matrix is arranged is used. The light receiving position detecting means can create a waveform curve of signal intensity from the light receiving signal output from the light receiving sensor, for example, and detect the peak position of the curve as the light receiving position.

  Moreover, the comparison of the estimated value of the inter-irradiation distance performed by the normal distance selection unit can be performed, for example, by calculating the difference between the two estimated values of the inter-irradiation distance and evaluating the difference. In this case, an estimated value of the inter-irradiation distance in which the difference is within a predetermined amount can be selected as the normal inter-irradiation distance. The predetermined amount can be appropriately changed according to the length of the estimated value of the inter-irradiation distance to be compared.

  In addition, the data processing means, when the normal distance selection means has selected a plurality of inter-irradiation distances, the previous distance selected by the normal distance selection means before the plurality of irradiation distances selected this time It is preferable to further include a normal distance determining means for comparing and determining a normal inter-irradiation distance based on the comparison result. According to this, even if a plurality of normal inter-irradiation distances are selected by the normal distance selection unit, the normal distance selection unit and the current normal distance selection previously selected by the normal distance selection unit by the normal distance selection unit By comparing the plurality of inter-irradiation distances selected by the means, the most suitable one of the plurality of inter-irradiation distances can be determined as the regular inter-irradiation distance. For this reason, the distance between irradiations can be determined more accurately, and in the case of performing many shape measurements, the influence of secondary reflection can be further eliminated than in the prior art.

  In this case, the normal distance determining means compares, for example, the average distance of the irradiation distances selected up to n times before by the normal distance selection means and the plurality of irradiation distances selected by the normal distance selection means this time, An inter-irradiation distance closest to the average distance can be determined as a regular inter-irradiation distance.

  The data processing means includes shape data creation means for creating shape data of a measurement object based on the distance between irradiations selected by the normal distance selection means or the distance between irradiations determined by the normal distance determination means. There should be. According to this, accurate shape data of a measurement object can be created. Further, the data processing means includes an abnormal data exclusion means for excluding data that does not correspond to the shape data of the measurement object by comparing each of the shape data created by the shape data creation means with the shape data of a neighboring position. Further, it may be provided. According to this, since the shape data affected by the secondary reflected light can be excluded as a result by deleting the data that does not correspond to the shape data by the abnormal data excluding means, the shape with higher accuracy is obtained. Data can be created.

  In this case, the abnormal data excluding means uses the shape data of the shape data created by the shape data creating means as inspection data, and the distance between the inspection data and the shape data adjacent thereto or the inspection data and the adjacent data. If the predetermined axial distance (the x-axis direction distance, the y-axis direction distance, the z-axis direction distance) with the shape data to be measured is equal to or greater than a predetermined amount, the inspection data may be excluded as abnormal data. it can. The predetermined axial distance may be an axial distance parallel to a direction from the laser beam irradiation device toward the measurement target. The abnormal data excluding means extracts a plurality of adjacent shape data from the shape data created by the shape data creating means, linearly approximates these shape data from the extracted shape data by the least square method, etc. When the angle formed with the predetermined axis is equal to or larger than the predetermined angle or smaller than the predetermined angle, the shape data whose distance from the approximate line is equal to or smaller than the predetermined value can be excluded as abnormal data. Further, when the shape data to be excluded is specified by some means, the abnormal data exclusion means can be means for excluding the neighboring data (for example, adjacent shape data) of the shape data as abnormal data.

  The plurality of light receiving sensors are preferably arranged in a plane perpendicular to the laser beam irradiated from the laser beam irradiation device and equidistant from the laser beam irradiation device (or laser light source). The plurality of light receiving sensors are preferably arranged at symmetrical positions with respect to the laser light irradiation device or the laser light source. By adopting such an arrangement form of the light receiving sensors, the estimated value of the inter-irradiation distance calculated from the light receiving position of the secondary reflected light is greatly different among the plurality of light receiving sensors, so that it is easy to specify the normal inter-irradiation distance. Thus, the normal distance between the irradiation can be more reliably selected by the normal distance selection means.

  Moreover, the measurement object to which the shape measuring apparatus of the present invention is applied may be a character, a symbol, or a design stamped on an object made of metal. If the cross-section is V-groove, such as a stamped letter, and is formed on a highly reflective member such as metal, the shape is accurately measured because it is more strongly affected by secondary reflected light when measuring the shape. Measurement cannot be performed. In such a case, the shape measurement can be accurately performed by using the shape measuring apparatus of the present invention.

  The measurement object to which the shape measuring apparatus of the present invention is applied includes a surface shape after forming a metal object, a surface shape of an object having a reflectance of a predetermined value or more, a surface shape having a recess, and a surface shape having a step. Any of the surface shapes may be used. In measuring the three-dimensional shape of an object, any of these shapes may be strongly influenced by secondary reflection. Therefore, the present invention is used when measuring the three-dimensional shape of an object having such a shape. By applying the shape measuring apparatus, it is possible to accurately measure the three-dimensional shape of the object.

  By the way, the above-mentioned present invention is based on the fact that the distance between irradiations obtained from the light receiving positions of the regular reflected light is equal among the plurality of light receiving sensors, and the distance between the irradiations from the light receiving positions of the reflected light in the plurality of light receiving sensors. An estimated value is obtained, and the obtained inter-irradiation distance estimated values are compared with each other to select a normal inter-irradiation distance. In this case, if the light receiving position of the reflected light from the same irradiation site in the light receiving area of the light receiving sensor is unified among the plurality of light receiving sensors, the light receiving position of the regular reflected light is substantially the same position between the light receiving sensors. Therefore, without obtaining the inter-irradiation distance, it is possible to select the light receiving position (normal light receiving position) of the regular reflected light by comparing the light receiving positions of the plurality of light receiving sensors.

  Therefore, another feature of the present invention based on the above knowledge is that a laser beam irradiation device that irradiates a measurement target while scanning the laser beam and a laser that has a light receiving region and is irradiated from the laser beam irradiation device to the measurement target. A plurality of light receiving sensors that receive reflected light of the light within the light receiving region and output a light receiving signal indicating the amount of light received in the light receiving region, and a shape of the measurement target based on the light receiving signals output by the plurality of light receiving sensors Data processing means for calculating shape data representing the position, and the data processing means receives light reception signals from the plurality of light receiving sensors, and positions in the light receiving area based on the received light reception signals. The light receiving position detecting means for detecting the light receiving position where the light receiving amount reaches a peak for each light receiving sensor, and the light receiving position detecting means for each light receiving sensor. The light receiving position compared respectively, it is to a shape measuring apparatus and a normal receiving position selecting means for selecting the light receiving position as the light receiving position of the regular match within a predetermined tolerance. According to this, the same effect as the above-described invention can be obtained without obtaining the estimated value of the distance between irradiation from the light receiving position.

  In this case, it is preferable that the two light receiving sensors are arranged in a plane perpendicular to the optical axis of the laser light emitted from the laser light source and in a symmetrical position with the laser light source as the center. By arranging the light receiving sensors in this way, when the respective light receiving sensors receive regular reflected light, the light receiving positions can be unified. That is, the regular reflected light receiving position can be made the same in all the light receiving sensors. In addition, when the regular light receiving position selecting means selects a plurality of light receiving positions, the data processing means compares the light receiving positions previously selected by the regular light receiving position selecting means with the plurality of light receiving positions selected this time. Further, it is possible to further include normal light receiving position determining means for determining a normal light receiving position based on the comparison result. Further, the data processing means obtains an inter-irradiation distance from the light-receiving position selected by the normal light-receiving position selecting means or the light-receiving position decided by the normal light-receiving position determining means, and obtains the shape data of the measurement object based on the obtained inter-irradiation distance. It may be provided with shape data creating means for creating. Further, the data processing means includes an abnormal data exclusion means for excluding data that does not correspond to the shape data to be measured by comparing each of the shape data created by the shape data creation means with the shape data at the neighboring position. It can also be.

  Another feature of the present invention is a shape measurement method for measuring the shape of a measurement object, which includes a laser light source that emits laser light and a scanning unit that scans the laser light emitted from the laser light source. A laser light irradiation step of irradiating the measurement target with laser light from the irradiation device; a light reception step of receiving reflected light of the laser light irradiated on the measurement target by a plurality of light receiving sensors having a light receiving region; Based on the reflected light received by each of the light receiving sensors, based on the light receiving position detecting step for detecting the light receiving position of the reflected light in the light receiving region of each light receiving sensor, and on the light receiving position detected in the light receiving position detecting step, Receives the estimated distance between the laser beam irradiation device and the laser beam irradiation site on the measurement target. The distance calculation step calculated for each position is compared with the estimated value of the inter-irradiation distance calculated for each light receiving position in the distance calculation step, and the estimated inter-irradiation distance that matches within a predetermined allowable range is A shape measurement method comprising: a normal distance selection step that is selected as an inter-irradiation distance; and a shape data creation step that creates shape data of a measurement object based on the inter-irradiation distance selected in the normal distance selection step. It is in. According to the above-described shape measuring method, like the above-described shape measuring apparatus of the present invention, the shape data of the measurement target can be accurately created based on the regular inter-irradiation distance.

(First embodiment)
The first embodiment of the present invention will be described below. FIG. 1 is an overall view of a shape measuring apparatus according to a first embodiment of the present invention. In the figure, a shape measuring apparatus 1 includes a flat measuring table 2, a support 3 attached on the measuring table 2, a measurement camera 10 movably attached to the support 3, and a measurement camera 10. And a feed motor 30 for moving.

  As shown in the figure, the measuring table 2 is formed in a rectangular shape with the left-right direction as the longitudinal direction. The support 3 has two legs 3a, 3a erected from the approximate center of each short side of the measuring table 2 and the longitudinal direction of the measuring table 2 so as to connect the upper portions of the two legs 3a, 3a. Is formed in a substantially U-shape as a whole. The support portion 3b extends so as to be substantially parallel to the upper surface of the measurement table 2. A long hole 3c is formed in the support portion 3b along the axial direction. A guide groove (not shown) is formed on the longitudinal side wall of the long hole 3c. The measurement camera 10 is fitted in the long hole 3c while being locked in the guide groove.

  The feed motor 30 is attached to one end side of the long hole 3c formed in the support portion 3b. The output shaft of the feed motor 30 is connected to the measurement camera 10 by power transmission means such as a belt (not shown). Therefore, the measurement camera 10 can be moved in the longitudinal direction of the support portion 3 b along the guide groove in the long hole 3 c by driving the feed motor 30. Moreover, the measurement camera 10 includes a laser light source therein, and laser light emitted from the laser light source is scanned in a direction perpendicular to the longitudinal direction of the support portion 3b. While the scanning of the laser beam is performed, the measurement camera 10 is moved in the long axis direction of the support portion 3b by driving the feed motor 30, so that the laser beam is emitted from the measurement camera 10 over almost the entire upper surface of the measurement table 2. Will be irradiated.

  A measurement object OB is placed on the measurement table 2. In the present embodiment, the shape measuring apparatus 1 performs a stamped shape measurement for measuring the shape of a character (a stamped character “ABC” in FIG. 1) stamped in a groove shape on the surface of the measurement object OB. In addition, in order to display the shape data as coordinate values, the moving direction in which the measurement camera 10 moves by driving the feed motor 30 is orthogonal to the y-axis direction and the y-axis direction, as shown in FIG. A direction in which the irradiated laser beam is scanned is defined as an x-axis direction, a direction orthogonal to the x-axis direction and the y-axis direction, that is, a direction perpendicular to the upper surface of the measurement table 2 is defined as a z-axis direction.

  FIG. 2 is an internal perspective view of the measurement camera 10 as viewed from the y-axis direction, and FIG. 3 is an internal perspective view of the measurement camera 10 as viewed from the z-axis direction. As shown in FIGS. 2 and 3, the measurement camera 10 is configured to include a case 11 and various components arranged in the case 11. The case 11 is formed in a rectangular parallelepiped shape, and is attached to a guide groove formed in the support portion 3b so that the longitudinal direction of the case 11 is parallel to the longitudinal direction of the support portion 3b as shown in FIG.

  The case 11 includes various components such as a laser light source 12, a collimator lens 14, a galvano mirror 16, a swing motor 18, a first condenser lens 20, a second condenser lens 22, a first image sensor 24, and a second image sensor. 26 is arranged. The laser light source 12 emits laser light to the outside based on a command from a laser light driving circuit 12a (see FIG. 4), and a laser diode or other light emitting element can be used. The collimating lens 14 is disposed facing the laser light source 12, and the laser light from the laser light source 12 is incident to make the laser light parallel light.

  The galvanometer mirror 16 has an elongated rectangular parallelepiped shape as well shown in FIG. 3, and its longitudinal direction is parallel to the longitudinal direction of the support portion 3b of the support 3 (that is, parallel to the longitudinal direction of the case 11). In the case 11. Laser light emitted from the laser light source 12 and converted into parallel light by the collimator lens 14 is incident on the galvanometer mirror 16 and is reflected with a reflection angle equal to the incident angle. At this time, the laser light is preferably incident on the galvanometer mirror 16 from a direction perpendicular to the longitudinal direction of the galvanometer mirror 16. The laser beam reflected by the galvanometer mirror 16 is irradiated to the outside from a window or opening (not shown) formed in the case 11.

  The output shaft 18a of the swing motor 18 is connected to one end in the longitudinal direction of the galvanometer mirror 16 (the right end in FIG. 3), and the galvanometer mirror 16 is rotated about the long axis by the swing motor 18 being driven to swing. Swing. By this swinging operation, the incident angle and the reflection angle of the laser light incident on the galvanometer mirror 16 are continuously changed. For this reason, as shown by arrows A, B, and C in FIG. 2, the irradiation direction of the laser light reflected by the galvano mirror 16 also oscillates in conjunction with the oscillating operation of the galvano mirror 16, and the laser in the irradiation direction is oscillated. Light is scanned in the x-axis direction. The laser light source 12, the collimating lens 14, the galvanometer mirror 16, and the swing motor 18 constitute a laser beam irradiation device that irradiates the measurement target while scanning the laser beam, and the galvanometer mirror 16 and the swing motor 18 emit the laser beam. A scanning means for scanning is configured.

  The first condensing lens 20 and the second condensing lens are convex lenses, and in particular, the light incident from the outside, in particular, the reflected light emitted from the laser light source 12 through the collimating lens 14 and the galvanometer mirror 16 and reflected by the measurement object. Are condensed and imaged on the first image sensor 24 and the second image sensor 26. Each of the first image sensor 24 and the second image sensor 26 is an image pickup device (light receiving sensor) having a line-shaped light receiving region in which photo sensors (for example, CCDs) are arranged in a line, and light received for each pixel (pixel). Is converted into an electrical signal (light reception signal) representing the amount of received light and output. The various parts in the case 11 described above are shown as parts related to the present invention, and other parts may be provided in an actual product.

  As shown in FIG. 3, the first image sensor 24 and the second image sensor 26 are arranged so as to be symmetrical with respect to the laser light source 12. Specifically, the first image sensor 24 and the second image sensor 26 are arranged at symmetrical positions around the laser light source 12 in a plane perpendicular to the optical axis of the laser light emitted from the laser light source 12. Has been. For this reason, the distance from the laser light source 12 to the first image sensor 24 and the distance from the laser light source 12 to the second image sensor 26 are made equal. The first image sensor 24 and the second image sensor 26 correspond to a plurality of light receiving sensors of the present invention.

  As shown in FIG. 1, the shape measuring apparatus 1 includes a three-dimensional image processing device 40, a controller 50, an input device 52, and a display device 54. The controller 50 controls a drive control command signal for controlling the drive state to the feed motor 30 based on an input command inputted from the input device 52, and controls the swing state of the galvano mirror 16 to the swing motor 18 of the measurement camera 10. An oscillation control command signal for controlling the emission of laser light to the laser light source 12 of the measurement camera 10 (specifically, a laser light driving circuit 12a connected to the laser light source 12). Such control information is input to the three-dimensional image processing apparatus 40. The three-dimensional image processing apparatus 40 receives a signal indicating a driving amount from a feed motor 30 (specifically, an encoder attached to the feed motor 30), and an oscillation motor 18 of the measurement camera 10 (specifically, an encoder attached to the oscillation motor 18). ) From the first and second image sensors 24 and 26, respectively, and signals indicating the amount of oscillation of the galvano mirror 16 are input, and the measurement object is based on these input signals and control information input from the controller 50. The shape data is calculated, and the calculated result is output to the display device 54.

  In the shape measuring apparatus 1 having the above configuration, when an operator inputs a measurement start command to the controller 50 via the input device 52, the controller 50 sends a laser beam emission control command and a laser beam scanning control command to the measurement camera 10. In addition to outputting, a drive control command is output to the feed motor 30. As a result, laser light is emitted from the laser light source 12, and the galvano mirror 16 is swung by driving the swing motor 18, so that the laser light is scanned in the x-axis direction. Along with this, the measurement camera 10 is moved along the longitudinal direction of the support portion 3b, that is, the y-axis direction by driving the feed motor 30. By simultaneously performing the scanning of the laser light and the movement of the measurement camera 10, the laser light is irradiated on the entire upper surface of the measurement object OB placed on the measurement table 2 (laser light irradiation step).

  The laser light irradiated on the upper surface of the measurement object OB is scattered at the irradiation site on the measurement object OB. A part of the scattered light is reflected by the galvanometer mirror 16 and received by the first image sensor 24 through the first condenser lens 20, and another part of the scattered light is reflected by the galvanometer mirror 16 and second condensed. Light is received by the second image sensor 26 via the lens 22 (light receiving step). Then, light reception signals are output from the first and second image sensors 24 and 26, and the light reception signals are input to the three-dimensional image processing device 40.

  FIG. 4 shows the reflected state of the laser light and the first and second image sensors 24 and 26 when the laser light emitted from the laser light source 12 is applied to the stamped character portion formed on the measurement object OB. It is a figure which shows collectively the internal circuit of the three-dimensional image processing apparatus 40 for processing the light reception signal of the received reflected light. As shown in FIG. 4, the three-dimensional image processing apparatus 40 includes a first image sensor drive circuit 42, a second image sensor drive circuit 44, and a data processing circuit 41 (data processing means). . The data processing circuit 41 includes a first signal processing unit 46, a second signal processing unit 48, and a comparison calculation unit 49. The first image sensor drive circuit 42 receives a light reception signal output from each pixel in the first image sensor 24, amplifies the light reception signal input, and uses the intensity of the amplified light reception signal as digital data for each pixel as a first signal. The data is output to the processing unit 46. The second image sensor drive circuit 44 receives a light reception signal output from each pixel of the second image sensor 26 and amplifies the received light reception signal, and performs second signal processing using the intensity of the amplified light reception signal as digital data for each pixel. To the unit 48.

  FIG. 5 is a graph in which digital data for each pixel output from the image sensor drive circuits 42 and 44 is arranged and represented as a waveform. FIG. 5A is a waveform of the digital data output from the first image sensor drive circuit 42. ) Is a waveform of digital data output from the second image sensor drive circuit 44. In both graphs, the horizontal axis is the position of each pixel in the light receiving region in the image sensor (light receiving position), and the vertical axis is the digital data indicating the signal intensity (light receiving intensity) proportional to the amount of laser light received by that pixel. is there. As can be seen from the figure, the presence of portions showing a plurality of peaks is confirmed in the digital data output by any of the image sensor drive circuits. This indicates that both the first and second image sensors 24 and 26 receive secondary reflected light and other light in addition to regular reflected light.

  Here, as shown in FIG. 4, it is assumed that a groove having a V-shaped cross section representing a stamped character is formed on the surface (measurement surface) of the measurement object OB, and laser light is irradiated into the groove. To do. When the laser light from the laser light source 12 is applied to, for example, a point a in the V-shaped groove, the laser light is scattered at this point a, and a part of the scattered light is reflected as reflected light to the first condenser lens 20. To the first image sensor 24 and to the second image sensor 26 via the second condenser lens 22. However, when the inside of the V-shaped groove is, for example, mirror-finished and has a high reflectance, the laser light incident on the point a is reflected with a strong directivity, and this reflected light is reflected at another location in the groove. (Point b shown in FIG. 4) is irradiated again, and then scattered light is generated again (this is called secondary reflection). The scattered light at the secondary reflection site is also input to the first image sensor 24 via the first condenser lens 20 and to the second image sensor 26 via the second condenser lens 22. That is, when secondary reflection occurs and the reflected light at the secondary reflection site is input to each image sensor, each image sensor receives the reflected light at two light receiving positions. Further, if the laser light is repeatedly reflected in the groove, each image sensor receives the reflected light at more light receiving positions. For this reason, as shown in FIG. 5, the peaks of the received light intensity exist at a plurality of light receiving positions.

  As shown in FIG. 4, the first and second signal processing units 46 and 48 have first and second light receiving position detection units 46a and 48a and first and second distance calculation units 46b and 48b, respectively. The first and second light receiving position detectors 46a and 46b capture the digital data of the signal intensity for each pixel output from the first and second image sensor drive circuits 42 and 44 at predetermined time intervals and the captured digital data. The light receiving position indicating the peak of the received light intensity in a region that is equal to or greater than a predetermined value is calculated, and the calculated light receiving position is output to the first and second distance calculating units 46b and 48b (light receiving position detecting step). ). In the example shown in FIGS. 5A and 5B, the first light receiving position detection unit 46a selects a region showing a signal intensity equal to or higher than the threshold indicated by the dotted line in FIG. 5 outputs the light receiving position where the peak values represented by the peak numbers P1, P2, and P3 are detected to the first distance calculating unit 46b, and the second light receiving position detecting unit 48a is indicated by a dotted line in FIG. A region showing a signal intensity equal to or higher than the threshold is selected, and the light receiving position where the peak value represented by the peak numbers P4, P5, P6, and P7 is detected in this region is output to the second distance calculator 48b. The first and second light receiving position detectors 46a and 48a correspond to the light receiving position detector of the present invention.

As described above, the first and second distance calculation units 46b and 48b respectively receive the light receiving positions indicating the signal intensity peaks from the first and second light receiving position detection units 46a and 48a. The first distance calculating unit 46b is an estimate of the irradiation distance is the distance between the irradiation site of the laser light on the measurement target and the laser light source 12 (the distance estimate) L _A calculated in accordance with the principles of triangulation the second distance calculating unit 48b calculates the estimated value (distance estimate) L _B irradiation distance by the principle of triangulation similar (distance calculation step). The first distance calculation unit 46b and the second distance calculation unit 48b output the calculated distance estimation values L _A and L _B to the comparison calculation unit 49, respectively. The first distance calculation unit 46b and the second distance calculation unit 48b correspond to the distance calculation means of the present invention.

The comparison calculation unit 49 receives distance estimation values L _A and L _B from the first and second distance calculation units 46b and 48b, and also receives a swing signal indicating the swing state of the galvanometer mirror 16 from the swing motor 18. Based on the inputted swing signal, the irradiation angle θ that is an angle formed by the laser light irradiation direction and the z-axis direction at the time of the input is calculated. In addition, the comparison calculation unit 49 also sequentially receives a movement signal indicating the movement state of the measurement camera 10 from the feed motor 30, and based on the input movement signal, the origin position (initial position) of the laser light source 12 at the input time point. ) Is calculated. Then, each time the distance estimation values L _A and L _B are input from the first and second distance calculation units 46b and 48b, the comparison calculation unit 49 uses the calculated irradiation angle θ and the movement distance Y as the distance estimation value L _A. in association with the L _B, are stored sequentially in memory.

Therefore, as shown in Table 1, a data set of the distance estimated values L _A and L _B , the irradiation angle θ, and the moving distance Y is accumulated in the memory of the comparison calculation unit 49 as shown in Table 1. .

Here, when only regular reflected light is incident on the first and second image sensors 24 and 26, the distance estimation values L _A and L _B input to the comparison calculation unit 49 are one by one. Since each value is substantially the same, the distance between irradiation can be obtained by selecting one of the two values or averaging the two values. However, when secondary reflected light is also incident on the first and second image sensors 24 and 26, there are a plurality of distance estimation values L _A and L _B input to the comparison calculation unit 49. distance that can not be determined, it is necessary to select plural distance estimate L _a, range estimates calculated from the receiving position of the regular reflected light L _a from the L _B, the L _B as an irradiation distance . Here, it will be described that the estimated distance values L _A and L _B calculated from the light receiving position of the secondary reflected light are not the correct distance between irradiations, and the values are also different. In the arrangement state of the laser light source 12 and the measurement object OB shown in FIG. 4, when the regular reflected lights L1 and L2 at the point a are respectively incident on the first and second image sensors 24 and 26, the triangulation is performed. Since one of the vertices of the triangle is the point a, the distance between the point a and the laser light source 12 (inter-irradiation distance) can be calculated based on the principle of triangulation. However, when the secondary reflected light at the point b is incident on the image sensors 24 and 26, the point b does not become the vertex of the triangle in the triangulation. In this case, the intersections c and d of the optical axis L0 of the laser light emitted from the laser light source 12 and the optical axes L1 ′ and L2 ′ of the secondary reflected light from the point b toward the image sensors 24 and 26 are triangular. It becomes the apex of the triangle in the survey. Therefore, the distance calculated by the principle of triangulation based on the light receiving position of the secondary reflected light in the first image sensor 24 is the distance from the laser light source 12 to the point c (a distance shorter than the normal inter-irradiation distance). Yes, the distance calculated by the principle of triangulation based on the light receiving position of the secondary reflected light in the second image sensor 26 is the distance from the laser light source 12 to the point d (a distance longer than the normal inter-irradiation distance). Become. As described above, when the first and second image sensors 24 and 26 receive the secondary reflected light, the distance estimation values L _A and L _B calculated based on the light receiving positions are not correct inter-irradiation distances.

Further, the distance estimated values L _A and L _B calculated from the light receiving position of the secondary reflected light do not become the same value. On the other hand, the distance estimated values L _A and L _B calculated from the light receiving position of the regular reflected light are substantially the same. Therefore, by comparing the estimated value of the inter-irradiation distance calculated from the light receiving position in the first image sensor 24 with the estimated value of the inter-irradiation distance calculated from the light receiving position in the second image sensor 26, the normal inter-irradiation distance is obtained. It can be seen that it can be judged. That is, the distance between the estimated value L _A laser light source 12 and the point c of the irradiation distance calculated based on the light receiving position in the case of receiving the secondary reflection beam at the point b of FIG. 4 in the first image sensor 24 , and the other hand, the estimated value L _B of the irradiation distance calculated based on the light receiving position in the case of receiving the secondary reflection beam at the point b of FIG. 4 in the second image sensor 26 of the laser light source 12 and the point d The distance between the two is greatly different. However, the estimated value L _A of the irradiation distance calculated based on the light receiving position in the case of receiving a regular reflected light at a point in FIG. 4 in the first image sensor 24, the regular reflected light at the point a second It becomes equal to the estimated value L _{B of the} inter-irradiation distance calculated based on the light receiving position when light is received by the image sensor 26. Therefore, calculated based on the light receiving position in the case of receiving the reflected light receiving position in the estimated value L _A and the second image sensor 26 of the irradiation distance calculated based on the case of receiving the reflected light by the first image sensor 24 the irradiation distance estimates _{L B} and the comparison, respectively, either _{L a} and _{L B} are equal, or _{L a} and _{L B} are matched within a predetermined allowable range (i.e., the difference between _{L a} and _{L B} Can be estimated that the inter-irradiation distance is the normal inter-irradiation distance, and the light receiving position corresponding to the inter-irradiation distance is the normal reflected light receiving position. .

Based on the above, the comparison calculation unit 49 executes the programs shown in FIGS. 6A and 6B. This program is intended to be executed after storing the data shown in Table 1 in the memory is compared with the distance estimated value L _A and L _B extracts the value to match within a tolerance, the irradiation distance of regular Is the process of selecting. This program is started in step S100, the data set counter N is initialized (N = 0) in step S102, and then the normal distance candidate counter s is initialized (s = 0) in step S104. The data set counter N is a counter indicating the order of the data sets shown in Table 1, and the normal distance candidate counter s is a value in which the distance estimated value L _A and the distance estimated value L _B coincide with each other within an allowable range by subsequent calculations. Is a counter representing the number of Next, the comparison calculation unit 49 extracts the distance estimated values L _A (N, 0) to L _A (N, m _N ) in the _Nth data set from the data sets stored in the memory in step S106. Then, these values are substituted into A (0) to A (m _N ). Further, in step S108, distance estimation values L _B (N, 0) to L _B (N, p _N ) in the same data set are extracted, and these values are substituted into B (0) to B (p _N ). To do. Thereafter, the comparison calculation unit 49 initializes the first distance estimated value counter m (m = 0) in step S110, and initializes the second distance estimated value counter p (p = 0) in step S112.

Next, in step S114, the comparison calculation unit 49 determines whether the absolute value of the difference between A (m) and B (p) is less than the tolerance α. When the absolute value is less than the tolerance α, the estimated value L _A represented by the value A (m) at that time (or the estimated value L _B represented by the value B (p)) is normal reflected light. There is a high possibility that the distance is calculated based on the light receiving position. Accordingly, in this case, the distance estimation value L _A represented by A (m) (or the distance estimation value L _B represented by B (p)) is stored as a normal distance candidate, and the process proceeds to step S116. In step S116, A (m) is substituted into the normal distance candidate C (s) and stored (in this case, B (p) may be substituted into the normal distance candidate C (s)). Next, the comparison calculation unit 49 proceeds to step S118, increments the normal distance candidate counter s in step S118, and further proceeds to step S120 to increment the second distance estimated value counter p.

On the other hand, if the absolute value of the difference between A (m) and B (p) is not less than the tolerance α in step S114, the estimated distance value L _A and the value B represented by the value A (m) at that time (p) distance estimate represented by L _B are not both irradiation distance calculated based on the light reception position of the normal, potentially calculated distance based on the light reception position, such as the secondary reflection beam Is expensive. In this case, there is a high possibility that these estimated distance values are not regular inter-irradiation distances. Therefore, the process proceeds directly to step S120 without executing steps S116 and S118, and the second distance estimated value counter p is incremented. Subsequently, the comparison operation unit 49, at step S122 the second distance estimate counter p determines whether there are less _{p N.} Here, p _N is the number representing the number of N-th distance estimate L _B stored in the data sets (the number obtained by subtracting 1 from the number). If p is p _N or less, it can be determined that no finished comparison of all B and (p) and A (m), in this case returns to the step S114, the updated increments B (p ) And A (m), it is determined whether or not the absolute value of the difference is less than the tolerance α. By repeating such determination, the values of A (m) and all B (p) are compared, and the value A (m) when the difference is less than the distance difference α is the normal distance candidate C (s). Remembered.

If the second distance estimate counter p is determined to be greater than p _N at step S122, since all the B (p) can be determined to have been compared with the A (m), the next step S124 in this case willing increments m, further first distance estimate counter m proceeds to step S126 to judges whether or not more than m _N. Here, m _N is the number representing the number of N-th distance estimate L _A stored in the data sets (the number obtained by subtracting 1 from the number). If m is less than or equal to m _N, so it can be determined that no finished comparison of all A and (m) and B (p), initialize p in this case returns to the step S112 (p = 0) In step S114, it is determined whether the absolute value of the difference between A (m) and all B (p) newly incremented and updated is less than the tolerance α.

In the processing from step S112 to step S126, the value of A (m) is fixed, the value of B (p) is changed one by one, the comparison determination in step S114 is performed, and all the determinations are completed. , A (m) is fixed to the next value, and the value of B (p) is changed one by one again and the determination in step S114 is performed. Thereby, the absolute value of the difference between A (m) and B (p) for all values of A (0) to A (m _N ) and all values of B (0) to B (p _N ). Is less than the tolerance α, and when the absolute value is less than the tolerance α, A (m) at that time is sequentially substituted into the normal distance candidate C (s). When the m is determined to be greater than m _N is the determination of step S126, it can be determined as the end of the determination of all combinations, in this case, the process proceeds to step S128.

In step S128, it is determined whether the normal distance candidate counter s is greater than 0, that is, whether the normal distance candidate counter s has been incremented at least once in step S118. When this determination is “No”, the normal distance candidate counter s has never been incremented, and there is no value stored as the normal distance candidate C (s), that is, in the Nth data set. The normal inter-irradiation distance could not be obtained from the distance estimate (when the intensity of reflected light due to secondary reflection is strong and the peak position of the regular reflected light is hidden in the waveform of reflected light due to secondary reflection, etc. In step S134, the data set counter N is incremented. Next, the comparison calculation unit 49 proceeds to step S136 and determines whether the data set counter N is n or less. Here, n is a number (number obtained by subtracting 1 from the number) representing the number of data sets stored in time series in the memory of the comparison operation unit 49. If the data set counter N is equal to or less than n because it can be determined that there remains a dataset not compare yet distance estimate L _A and L _B, in this case returns to step S104, again the And the extraction of the normal distance candidate C (s) is repeated. If the data set counter N is greater than n, since the comparison between the range estimates L _A and L _B in all data sets can be determined to be finished, in this case, the process proceeds to step S138, execution of the program Exit.

If the normal distance candidate counter s is larger than 0 in step S128, that is, if the normal distance candidate counter s is incremented at least once in step S118, the process proceeds to step S130, and the normal distance candidate counter s is normalized in step S130. It is determined whether the distance candidate counter s is 1. If the normal distance candidate counter s is 1, that is, if the normal distance candidate counter is incremented only once in step S118, the value stored in the normal distance candidate C (s) from the Nth data set is C This means only one of (0). In this case, the stored value C (0) is regarded as a normal inter-irradiation distance, the process proceeds to step S132, and the normal distance candidate C (0) is substituted into the normal inter-irradiation distance L _d (N). Store in memory. Next, the process proceeds to step S133 to clear C (0) to C (s), and the process proceeds to step S134 to increment the data set counter N. Thereafter, the process proceeds to step S136, where it is determined whether or not the data set counter N is n or less. If it is determined that the data set counter N is n or less, the process returns to step S104 and the above comparison and normal distance candidates are again obtained. Repeat extraction of C (s). If the data set counter N is larger than n, the process proceeds to step S138, and the execution of this program is terminated. Through the processes in steps S102 to S136, a normal inter-irradiation distance is selected from a plurality of estimated values of the inter-irradiation distance. These processes correspond to the normal distance selection means and the normal distance selection step of the present invention.

On the other hand, if it is determined in step S130 that s is not 1, that is, if s is incremented twice or more in step S118 and a plurality of normal distance candidates C (s) are selected, a plurality of normal distance candidates C It is necessary to determine a normal distance candidate representing a normal distance between irradiations from (s). Therefore, in such a case, the process proceeds to step S140, and the normal inter-irradiation distance L _d (N) is determined from the plurality of normal distance candidates C (s) by the processing of step S140 to step S162. The processes in steps S140 to S162 correspond to the normal distance determining means and the normal distance determining step of the present invention. Note that a case where a plurality of normal distance candidates C (s) are extracted occurs when the peak positions of reflected light and other light due to secondary reflection coincide.

In the comparison operation unit 49 step S140, the irradiation distance between regular chosen before three than the current data set counter _{N L d (N-3)} , L d (N-2), L d (N -1) is called and the number of called regular inter-irradiation distances L _d is substituted into F. In this case, if the current data set counter N is 0, F is 0 because there is no previous data set. If the current data set counter N is 1, F is 1 or less. If the current data set counter N is 2, F is 2 or less. If the current data set counter N is 3 or more, F is 3 or less. . Even if N is 3 or more, any or all of the inter-irradiation distances L _d (N-3), L _d (N-2), and L _d (N-1) may not be extracted. F is 2 or less.

Next, the comparison calculation unit 49 determines whether or not the number F is 0 in step S142. When F is 0, there is no comparison target for determining which of the plurality of normal distance candidates C (s) is the normal inter-irradiation distance, and therefore among the plurality of normal distance candidates C (s) From this, the regular inter-irradiation distance L _d (N) cannot be determined. Therefore, in this case, the determination of the normal inter-irradiation distance L _d (N) is stopped, and the process returns to step S134 to proceed to the determination in the next data set.

If the number F is not 0, the process proceeds to step S144, and the normal distance candidate counter s is initialized (s = 0) in step S144. Next, the comparison calculation unit 49 proceeds to step S146, calculates the average value of the called regular irradiation distances L _d (N−3), L _d (N−2), and L _d (N−1), The absolute value of the difference between this average value and the distance candidate C (s) (s = 0) extracted in the current data set N is obtained, and the obtained absolute value is substituted into the temporary reference value E. In addition, in the average value calculation of step S146, 0 is substituted for the normal inter-irradiation distance that has not been obtained. Next, the comparison calculation unit 49 substitutes 1 for the normal distance candidate counter s in step S148, and further substitutes 0 for the temporary normal distance counter value q in step S149. The temporary normal distance counter value q is a counter value of a distance candidate C (s) that is considered to represent a normal distance between irradiation (the normal distance of the normal distance candidate C (s) stored in the temporary reference value E). Candidate counter s).

Subsequently, the comparison calculation unit 49 proceeds to the process of step S150, and in this step S150, the normal inter-irradiation distances L _d (N−3), L _d (N−2), and L _d (N−1) are calculated. The absolute value of the difference between the average and the normal distance candidate C (s) (s = 1) extracted in the current data set N is obtained, and the obtained absolute value is used as the comparison value D (s) (s = 1). substitute. Thereafter, the process proceeds to step S152, where it is determined whether the comparison value D (s) is less than the temporary reference value E. That the comparison value D (s) is less than the temporary reference value E indicates that the comparison value D (s) is closer to the average value than the temporary reference value E. It can be estimated that D (s) is more suitable for the regular distance between irradiation. Therefore, in this case, the process proceeds to step S154, and the comparison value D (s) is substituted into the temporary reference value E. Further, in step S156, the normal distance candidate counter s (in this case, s = 1) of the comparison value D (s) is set. Substituting into the temporary normal distance counter value q proceeds to step S158. On the other hand, if it is determined in step S152 that the comparison value D (s) is not less than the temporary reference value E, the processing of steps S154 and S156 is not performed (that is, the temporary reference value E and the temporary normal distance counter value q Proceed to step S158 (without updating).

Next, the comparison calculation unit 49 increments the normal distance candidate counter s in step S158 and proceeds to step S160, and determines whether the normal distance candidate counter s is equal to or _smaller than s _{max in} step S160. Here, s _max is the value of the normal distance candidate counter when A (m) is finally substituted for the normal distance candidate C (s) in step S116 in the current data set N. Therefore, when the normal distance candidate counter s is equal to or _smaller than s _max , it can be determined that there are still normal distance candidates C (s) that have not been used for the calculation in step S150. In this case, the process returns to step S150 and is updated. The absolute value of the difference between the obtained normal distance candidate C (s) and the average value is substituted into the comparison value D (s), and the determination in step S152 is performed. In this way, the normal inter-irradiation distance L selected in the data set up to three times before the current data set N is obtained by performing the processing of steps S150 to S160 for all the normal distance candidates C (s). _A normal distance candidate C (s) closest to the average value of _d (N-3), L _d (N-2), and L _d (N-1) is extracted. When the determination in step S160 is “No” and the determination for all the normal distance candidates C (s) is completed, the process proceeds to step S162. In step S162, the provisional normal finally updated. A normal distance candidate C (q) having a distance counter value q is determined (assigned) as a normal inter-irradiation distance L _d (N). Thereafter, the process returns to step S133, the values of the normal distance candidates C (0) to C (s) are cleared, and the process proceeds to step S134 to proceed to the determination in the next data set.

By the above process, unless the distance estimate L _A and distance estimate L _B does not match at all values, normal irradiation distance L _{d (N)} is determined in all datasets N.

In this embodiment, the normal inter-irradiation distances L _d (N−3), L _d (N−2), and L _d (up to three before the current data set N in the processing of step S144 to step S160. N-1) is used to determine the regular inter-irradiation distance L _d (N) in the current data set N, but the number of previous inter-irradiation distances used can be appropriately changed. In the present embodiment, the previous inter-irradiation distance is averaged, and the normal inter-irradiation distance L _d (N) is determined from a plurality of normal distance candidates C (s) by comparison with this average value. A straight line or a quadratic curve may be calculated from the previous inter-irradiation distance by the least square method to calculate an estimated value of the normal inter-irradiation distance in the current data set N, and may be compared with this estimated value.

After the regular inter-irradiation distance L _d (N) is determined in all the data sets N, the comparison calculation unit 49 calculates all the data from the irradiation angle θ, the movement distance Y, and the regular inter-irradiation distance L _d (N). The coordinate values (x, y, z) of the surface to be measured in set N are calculated. Here, the y coordinate value is the movement distance Y, the x coordinate value is L _d (N) sin θ, and the z coordinate value is L _d (N) cos θ. As a result, the three-dimensional shape data of the measurement object is obtained, and the shape of the measurement object can be displayed on the display device 54 based on the shape data. This coordinate value calculation step corresponds to the shape data creation means and the shape data creation step of the present invention.

  Even if the shape data of the measurement target is determined as described above, the shape data may include a small amount of abnormal data that does not represent the original surface shape of the measurement target. Therefore, the comparison calculation unit 49 performs a process (abnormal data exclusion process) for excluding the shape data that does not appear to represent the shape data to be measured from the acquired shape data. This abnormal data excluding process corresponds to the abnormal data excluding means of the present invention.

  An example of the abnormal data exclusion process will be described. The comparison calculation unit 49 first arranges all the shape data in the order of x coordinate value or y coordinate value, extracts a point (inspection point) from the list, and extracts the extracted inspection point. And the difference in z-coordinate values between points adjacent to both sides of the inspection point. If both of the absolute values of the differences are larger than the predetermined value β, the comparison calculation unit 49 determines that the inspection point is abnormal data, and excludes the inspection point shape data. Such processing is performed for all shape data. FIG. 7 is a diagram showing shape data on the x (or y) -z plane, and shows a process of extracting abnormal data by the above method. In the figure, normal shape data is indicated by black dots, and abnormal data is indicated by white dots. In FIG. 7, when the shape data D1 is used as the inspection point, the difference in the z coordinate value between the inspection point and the adjacent shape data D0 is less than the predetermined value β. On the other hand, the difference in z-coordinate value between the inspection point and the adjacent shape data D2 is equal to or greater than a predetermined value β. In this case, it is determined that the data is normal because the difference in the z coordinate value between the adjacent shape data is less than the predetermined value β. Similarly, the shape data D3 and D4 are also determined to be normal data (the difference in z coordinate values between the shape data D4 and the adjacent shape data on both sides is less than the predetermined value β). However, when the shape data D2 is used as the inspection point, the difference in the z coordinate value from the shape data D1 adjacent to the inspection point is equal to or larger than the predetermined value β, and the shape data D3 adjacent to the inspection point is different from the shape data D3. The difference between the z-coordinate values is also equal to or greater than the predetermined value β. In this case, since the difference in the z coordinate value between any adjacent data is equal to or greater than the predetermined value β, the comparison calculation unit 49 determines that the shape data D2 is abnormal data and excludes it from the shape data.

  Since the z coordinate value represents the distance between the measurement target and the laser light source, it is considered that the difference in the z coordinate value between adjacent shape data is small. Therefore, when this difference is more than a predetermined value between adjacent data, the possibility of abnormal data in which the inspection point data does not represent shape data increases. Therefore, the shape of the measurement object can be represented only by the normal shape data by performing the above-described processing and excluding abnormal data in view of the above. In this case, as shown in FIG. 7, it is preferable to exclude the inspection point as abnormal data when any difference in z-coordinate values between the points on both sides adjacent to the inspection point is larger than a predetermined value β. The magnitude of the predetermined value β can be appropriately selected depending on the shape of the measurement target.

Explaining another example of the abnormal data exclusion processing, the comparison calculation unit 49 first arranges all the shape data in the order of the x coordinate value or the y coordinate value, selects a point (inspection point) from them, and selects the selected data. A plurality of continuous shape data are extracted so as to include an inspection point and shape data adjacent to the inspection point. The comparison calculation unit 49 linearly approximates these shape data by the least square method based on the extracted plurality of shape data. When the angle γ formed between the obtained approximate straight line and the z-axis is equal to or smaller than the predetermined angle γ ₀ , the distance from the approximate straight line in the shape data used to obtain the approximate straight line is predetermined. The following shape data is determined as abnormal data, and shape data determined as abnormal data is excluded. FIG. 8 is a diagram showing shape data on the x (or y) -z plane, and shows a process of extracting abnormal data by the above method. In the figure, normal shape data is indicated by black dots, and abnormal data is indicated by white dots. This process is applied when the measurement target is nearly perpendicular to the direction of laser light irradiation. When measuring the shape of the stamped character formed on the surface of the metal material, the V-shaped groove forming the stamped character may be formed with an inclination relatively close to the z-axis direction. . In such a case, the predetermined angle γ ₀ may be set to an angle smaller than the inclination angle of the V-shaped groove.

  Further, the comparison calculation unit 49 additionally calculates abnormal data from the shape data determined as abnormal data by the abnormal data excluding process, and excludes the abnormal data including the calculated additional abnormal data. FIG. 9 is a diagram showing the calculation of such additional abnormality data. This figure shows shape data on the xy coordinate system. In the figure, abnormal shape data is calculated by adding normal shape data as black dots and abnormal data as white dots. The outline is indicated by a white dot with a dotted line.

  In FIG. 9, the abnormality data is shape data D9. Of the shape data whose x-coordinate value matches the x-coordinate value of the abnormal data D9 within a predetermined range, the comparison calculation unit 49 converts the two shape data whose y-coordinate values are adjacent to the abnormal data D9 to the abnormal data D9. Is calculated as adjacent data in the y-axis direction. In the case of FIG. 9, D3 and D13 are y-axis direction adjacent data. Further, the comparison calculation unit 49 converts two shape data whose x coordinate values are adjacent to the abnormal data D9 out of the shape data whose y coordinate value matches the y coordinate value of the abnormal data D9 within a predetermined range, to the shape data D9. As x-axis direction adjacent data. In the case of FIG. 9, D8 and D10 are adjacent data in the x-axis direction. In this embodiment, since the shape of the measurement target is measured while the laser light source is scanned in the x-axis direction and moved in the y-axis direction, the measurement points on the measurement target are arranged in a sequence of measurement points in FIG. As shown, the zigzag route is followed along the y-axis direction on the xy plane. Therefore, since the x-axis direction adjacent data is the shape data D8 and D10 measured and stored before and after the abnormal data D9, the x-axis direction adjacent data may be calculated as shape data stored before and after the abnormal data.

  The comparison calculation unit 49 regards the y-axis direction adjacent data D3 and D13 and the x-axis direction adjacent data D8 and D10 calculated as described above as abnormal data, and sets the abnormal data D3, D8, D9, D10, and D13 including these data as abnormal data. exclude. As a result, the shape of the measurement object can be represented more reliably only by the shape data representing the regular shape.

  As described above, the shape measuring apparatus 1 of the present embodiment includes the plurality of image sensors 24 and 26, and the irradiation distance corresponding to the light receiving position where the plurality of image sensors 24 and 26 receive the reflected light. An estimated value is calculated for each light receiving position, and the calculated estimated values of the inter-irradiation distances are compared, and an estimated value of the inter-irradiation distance that matches within a predetermined allowable range is selected as the normal inter-irradiation distance. This is based on the fact that when regular reflected light is received by a plurality of image sensors (light receiving sensors), the irradiation distances calculated from the respective light receiving positions are substantially equal. Therefore, according to the shape measuring apparatus 1 of the present embodiment, the normal light receiving position and the normal inter-irradiation distance can be accurately calculated, and accurate shape data can be created based on this.

(Second Embodiment)
In the above embodiment, the estimated value of the inter-irradiation distance is compared for each light receiving sensor, and the estimated inter-irradiation distance that matches within the allowable range is selected as the normal inter-irradiation distance. The light receiving positions themselves in the respective light receiving sensors may be compared, a light receiving position that matches within an allowable range may be selected as a normal light receiving position, and a normal inter-irradiation distance may be calculated based on the selected light receiving position. . In this case, the first and second image sensors 24 and 26 can be suitably applied when they are arranged symmetrically to the laser light source 12 in a plane perpendicular to the optical axis of the laser light. When the image sensors 24 and 26 are arranged as described above, the relationship between the waveform of the signal intensity output from one light receiving sensor and the waveform of the signal intensity output from the other light receiving sensor is shown in FIG. And the relationship shown in FIG. In this case, the peak at which the light receiving positions match in both waveforms (in the case of FIG. 5, peak positions P3 and P4) is a peak representing the amount of normal reflected light received, and the light receiving position at which this peak is generated is normal. This is the light receiving position.

The shape measuring apparatus of the second embodiment is basically the same as the shape measuring apparatus 1 described in the first embodiment, but the first signal processing unit 46 and the second signal processing unit 48 shown in FIG. The light receiving positions detected by the first and second light receiving position detectors 46 a and 48 a are directly output to the comparison calculator 49 without calculating the estimated distance. Therefore, the comparison calculation unit 49 stores the data sets shown in Table 2 in order in the memory instead of the data sets shown in Table 1 above.

The comparison calculation unit 49 executes the programs shown in FIGS. 10A and 10B instead of the programs shown in FIGS. 6A and 6B. About the program shown to FIG. 10A and FIG. 10B, the part which performs the same process as the program shown to FIG. 6A and FIG. 6B is shown with the same step number. In this program, the comparison target in step S114 is not the estimated values L _A and L _{B of the} irradiation distance as shown in FIG. 6, but the light receiving positions J _A and J _B. Further, what is selected in step S132 is not the regular inter-irradiation distance L _d as shown in FIG. 6, but the regular light receiving position J _d . Further, the calculation in step S148 and step S150 is not a calculation for calculating the difference between the normal average distance between irradiations in the nearby data set and the normal distance candidates in the current data set as shown in FIG. This is a calculation for calculating the difference between the normal light receiving position average at and the normal light receiving position candidate in the current data set. Also, what is determined in step S162 is not the regular inter-irradiation distance L _d as shown in FIG. 6, but the regular light receiving position J _d . In the processing from step S102 to S138 of this program, the light receiving positions detected by the light receiving position detection means for each light receiving sensor are compared, and the light receiving positions that coincide with each other within a predetermined allowable range are selected as the normal light receiving positions. This corresponds to normal light receiving position selection means. Further, the processing from step S140 to S162 of this program is performed when the normal light receiving position selecting means selects a plurality of light receiving positions and the light receiving positions previously selected by the normal light receiving position selecting means and the currently selected light receiving positions. It corresponds to a normal light receiving position determining means for comparing the position and determining a normal light receiving position based on the comparison result. Since the flow of processing of this program is basically the same as that of the program shown in FIGS. 6A and 6B, its detailed description is omitted. According to the present embodiment, since a regular light receiving position is selected or determined, an inter-irradiation distance is calculated from the selected or determined regular light receiving position, and shape data is created using the calculated inter-irradiation distance. Can do.

  The present invention is not limited to the above embodiment, and various modifications can be made. In the above embodiment, the measurement camera 10 is moved linearly by the moving mechanism (feed motor 30) while scanning the laser light by the galvanometer mirror 16 and the swing motor 18, but the laser light is scanned by the scanning means. In addition, any form may be used as long as the reflected light from the measurement object is received by the light receiver via the scanning means. For example, the measurement camera 10 may scan laser light in two directions with two galvanometer mirrors or polygon mirrors, scan in one direction with one galvanometer mirror or polygon mirror, etc. The housing provided may be rotated. Further, without using a galvano mirror or a polygon mirror, a housing provided with a laser light source or a light receiver may be rotated in two directions, or may be moved linearly by a moving mechanism while rotating in one direction. Good.

  Further, in the above embodiment, two image sensors are arranged at opposite positions (symmetric positions) that are diametrically opposite with respect to the laser light source, but three or more image sensors are arranged at equal distances with the laser light source as the center. Then, the regular distance between irradiations may be calculated from a common distance in signals output by three or more image sensors. In the case of the first embodiment, the image sensor does not necessarily have to be equidistant from the laser light source. Since the distance from the signal output from each image sensor to the laser beam irradiation point is calculated and compared, a plurality of image sensors may be arranged at different distances from the respective laser light sources.

1 is an overall view of a shape measuring apparatus according to an embodiment of the present invention. It is the internal perspective view which looked at the measuring camera concerning this embodiment from the y-axis direction. It is the internal perspective view which looked at the measuring camera concerning this embodiment from the z-axis direction. The reflected state of the laser beam when the laser beam irradiated from the laser beam irradiation apparatus according to the present embodiment is irradiated onto the stamped character portion formed on the measurement object, and the first and second image sensors receive the reflected light. It is a figure which shows the internal circuit of the three-dimensional image processing apparatus for processing the light reception signal showing the emitted light. 4 is a graph in which digital data for each pixel output from the image sensor drive circuit according to the present embodiment is arranged and represented as a waveform, where (a) is a waveform of digital data output from the first image sensor drive circuit, and (b) is a waveform. It is a waveform of digital data output from the second image sensor drive circuit. It is a flowchart of the program for calculating | requiring the normal distance between irradiation which the comparison calculating part which concerns on 1st Embodiment performs. It is a flowchart of the program for calculating | requiring the normal distance between irradiation which the comparison calculating part which concerns on 1st Embodiment performs. It is the figure which displayed the shape data calculated | required in this embodiment on x (or y) -z coordinate system, and shows an example of the abnormal data exclusion process which excludes abnormal data from shape data. It is the figure which displayed the shape data calculated | required in this embodiment in x (or y) -z coordinate system, and shows the other example of the abnormal data exclusion process which excludes abnormal data from shape data. The figure which displayed the shape data calculated | required in this embodiment on an xy coordinate system, and shows the calculation process of additional abnormality data based on abnormality data. It is a flowchart of the program for calculating | requiring the normal light reception position which the comparison calculating part which concerns on 2nd Embodiment performs. It is a flowchart of the program for calculating | requiring the normal light reception position which the comparison calculating part which concerns on 2nd Embodiment performs.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Shape measuring apparatus, 10 ... Measuring camera, 12 ... Laser light source, 12a ... Laser light drive circuit, 14 ... Collimating lens, 16 ... Galvano mirror, 18 ... Swing motor, 24 ... 1st image sensor (light receiving sensor), 26 ... 2nd image sensor (light receiving sensor), 30 ... Feed motor, 40 ... 3D image processing device, 41 ... Data processing circuit (data processing means), 46 ... 1st signal processing part, 46a ... 1st light receiving position detection Part (light receiving position detecting means), 46b ... first distance calculating part (distance calculating means), 48 ... second signal processing part, 48a ... second light receiving position detecting part (light receiving position detecting means), 48b ... second distance calculating Part (distance calculation means), 49 ... comparison calculation part (normal distance selection means, normal light receiving position selection means, normal distance determination means, abnormal data exclusion means), 50 ... controller, 52 ... input device , 54 ... display unit, _{J A,} J B _... light receiving position, the light receiving position of J d _... regular, _{L A,} L B _... distance estimate, irradiation distance of L d _... regular

Claims (14)

A laser beam irradiation device that irradiates a measurement object while scanning the laser beam;
A plurality of light receiving sensors having a light receiving region, receiving reflected light of the laser light irradiated to the measurement object from the laser light irradiation device in the light receiving region, and outputting a light receiving signal representing the amount of light received in the light receiving region; ,
Data processing means for calculating shape data representing the shape of the measurement object based on the light reception signals output by the plurality of light receiving sensors,
The data processing means includes
A light receiving position that receives a light receiving signal from the plurality of light receiving sensors and detects a light receiving position that is a position in the light receiving region and has a peak light receiving amount for each light receiving sensor based on the input light receiving signal. Detection means;
An estimated value of an inter-irradiation distance, which is a distance between the laser light irradiation device corresponding to the light receiving position detected by the light receiving position detection unit for each light receiving sensor and a laser light irradiation site on the measurement target, is received for each light receiving position. A distance calculating means for calculating
A normal distance selection unit that compares the estimated values of the inter-irradiation distances calculated for each light receiving position by the distance calculation unit, and selects the estimated values of the inter-irradiation distances that match within a predetermined allowable range as normal inter-irradiation distances; A shape measuring device comprising: In the shape measuring apparatus according to claim 1,
When the light receiving position detecting unit detects a plurality of light receiving positions from at least one light receiving signal, the normal distance selecting unit is configured to detect a plurality of light receiving positions detected from the one light receiving signal calculated by the distance calculating unit. Are compared with the estimated values of the inter-irradiation distances corresponding to the light-receiving positions detected from the other light-receiving signals calculated by the distance calculation means, and matched within a predetermined allowable range. An estimated value of an inter-irradiation distance is selected as a normal inter-irradiation distance. In the shape measuring device according to claim 1 or 2,
When the regular distance selection unit selects a plurality of inter-irradiation distances, the data processing unit compares the inter-irradiation distances previously selected by the normal distance selection unit with the plurality of inter-irradiation distances selected this time. The shape measuring apparatus further comprises normal distance determining means for determining a normal distance between irradiations based on the comparison result. In the shape measuring device according to any one of claims 1 to 3,
The data processing means includes shape data creation means for creating shape data of a measurement object based on the distance between irradiations selected by the normal distance selection means or the distance between irradiations determined by the normal distance determination means; and the shape data creation A shape measuring apparatus, further comprising: an abnormal data excluding unit that excludes data not corresponding to the shape data of the measurement target by comparing each of the shape data created by the unit with the shape data at a neighboring position. A laser beam irradiation device that irradiates a measurement object while scanning the laser beam;
A plurality of light receiving sensors having a light receiving region, receiving reflected light of the laser light irradiated to the measurement object from the laser light irradiation device in the light receiving region, and outputting a light receiving signal representing the amount of light received in the light receiving region; ,
Data processing means for calculating shape data representing the shape of the measurement object based on the light reception signals output by the plurality of light receiving sensors,
The data processing means includes
A light receiving position that receives a light receiving signal from the plurality of light receiving sensors and detects a light receiving position that is a position in the light receiving region and has a peak light receiving amount for each light receiving sensor based on the input light receiving signal. Detection means;
A normal light receiving position selecting means for comparing the light receiving positions detected by the light receiving position for each of the light receiving sensors and selecting a light receiving position that coincides within a predetermined allowable range as a normal light receiving position. A shape measuring device. In the shape measuring apparatus according to claim 5,
When the light receiving position detecting unit detects a plurality of light receiving positions from at least one light receiving signal, the regular light receiving position selecting unit detects a plurality of light detected from the one light receiving signal detected by the light receiving position detecting unit. The light receiving position is compared with a light receiving position detected from another light receiving signal detected by the light receiving position detecting means, and a light receiving position that coincides within a predetermined allowable range is selected as a normal light receiving position. Shape measuring device. In the shape measuring device according to claim 5 or 6,
The data processing means, when the regular light reception position selection means has selected a plurality of light reception positions, compares the light reception positions previously selected by the regular light reception position selection means and the plurality of light reception positions selected this time, A shape measuring apparatus, further comprising: a normal light receiving position determining unit that determines a normal light receiving position based on the comparison result. The shape measuring apparatus according to any one of claims 5 to 7,
The data processing means includes shape data creation means for creating shape data of a measurement object based on a light receiving position selected by the normal light receiving position selecting means or a light receiving position determined by the normal light receiving position determining means; and the shape data creating A shape measuring apparatus, further comprising: an abnormal data excluding unit that excludes data not corresponding to the shape data of the measurement target by comparing each of the shape data created by the unit with the shape data at a neighboring position. In the shape measuring device according to any one of claims 1 to 8,
The shape measuring device, wherein the plurality of light receiving sensors are arranged in a plane perpendicular to the laser beam irradiated from the laser beam irradiation device and equidistant from the laser beam irradiation device. The shape measuring device according to any one of claims 1 to 9,
The shape measuring device, wherein the plurality of light receiving sensors are arranged at symmetrical positions with respect to the laser beam irradiation device. In the shape measuring device according to any one of claims 1 to 10,
A shape measuring apparatus, wherein the object to be measured is a character, a symbol, or a design stamped on an object made of metal. In the shape measuring device according to any one of claims 1 to 10,
The object to be measured is a surface shape after molding of an object made of metal, a surface shape of an object having a reflectance of a predetermined value or more, a surface shape having a recess, or a surface shape having a step. A feature measuring device. A shape measuring method for measuring the shape of a measurement object,
A laser light irradiation step of irradiating a laser beam to a measurement object while scanning the laser light from a laser light irradiation device having a laser light source that emits laser light and a scanning unit that scans the laser light emitted from the laser light source;
A light receiving step of receiving reflected light of the laser light irradiated to the measurement object by a plurality of light receiving sensors having a light receiving area;
A light receiving position detecting step for detecting a light receiving position of the reflected light in a light receiving region of each light receiving sensor based on the reflected light received by the plurality of light receiving sensors;
Based on the light receiving position detected in the light receiving position detecting step, an estimated value of an inter-irradiation distance that is a distance between the laser light irradiation device and a laser light irradiation portion on the measurement target is calculated for each light receiving position. A distance calculation step;
Normal distance selection step of comparing the estimated value of the distance between irradiations calculated for each light receiving position in the distance calculating step, and selecting the estimated value of the distance between irradiations within a predetermined allowable range as the normal distance between irradiations When,
Shape data creation step for creating shape data of a measurement object based on the distance between irradiation selected in the regular distance selection step;
The shape measuring method characterized by including. The shape measuring method according to claim 13,
When a plurality of inter-irradiation distances are selected in the regular distance selection step, the inter-irradiation distances previously selected by the regular distance selection means are compared with the plurality of inter-irradiation distances selected this time, A shape measuring method, further comprising a normal distance determining step for determining a normal inter-irradiation distance from the comparison result.

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