JP2009058311A - Marking inspection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a marking inspection device capable of shortening the measuring time, and measuring the depth of a marked character formed with a V-groove shape or a U-groove shape, and having less influence on measurement accuracy, even with a mirror-reflecting marked surface. <P>SOLUTION: Laser slit light sources 41-45 are supported on a moving stage 72 of a scanning unit 71 and can be moved in the Y-direction 73. Irradiation position of a slit light 31 from each laser slit light source 41-45 is imaged from the oblique upside by a corresponding CCD camera 81-85. The relation between each laser slit light source 41-45 and each CCD camera 81-85 is set so that regularly reflected light 91 of the slit light 31, reflected regularly by the marked plane 2, is not input directly into the corresponding CCD camera 81-85. An image acquired by each of CCD cameras 81-85 is analyzed by a control device 101. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a marking inspection apparatus for inspecting a stamped character or the like.

  Conventionally, when engraved characters are engraved on metal parts, metal plates, etc., the engraved characters are copied on paper to form a paper pioneer, and the depth is determined from the width dimension of the imprinted characters copied by this paper pioneer. I was expecting.

  In addition, as a method of actually measuring the depth of the marking, sampling inspection can be cited. In this sampling inspection, the stamped plate is cut and the depth is measured from the cross section, or a special gauge equipped with an extra fine measuring element. Was used to measure.

  However, in the method of assuming the depth from the width dimension of the engraved character described above, it takes time and the width dimension and the depth do not always coincide with each other.

  In addition, the method using a dedicated gauge takes time and is difficult to perform a complete inspection, and the method of cutting a stamped plate cannot perform a complete inspection.

  Therefore, the applicant of the present application has come up with a marking inspection device that solves these problems (for example, Patent Document 1).

  As shown in FIG. 6, the marking inspection apparatus includes a stage 801 that moves in the direction of the character string of the marking character. The stage 801 includes a laser device 804 that irradiates the marking surface 802 with slit light 803, and A camera 806 that images the regular reflected light 805 of the irradiated slit light 803 is provided. The camera 806 is disposed so as to face the laser device 804 and is configured so that the specularly reflected light 805 specularly reflected by the marking surface 802 can be input to the camera 806.

Thus, the marking character on the marking surface 802 can be inspected by a light cutting method in which the laser device 804 and the camera 806 are moved simultaneously.
Japanese Patent Application No. 2006-235367

  However, in such a conventional engraving inspection apparatus, inspection is performed by moving the laser device 804 and the camera 806 in the direction of the character string on the stage 801, so that it takes time when the number of arranged characters is large. There was a problem.

  In addition, due to the structure in which the depth of the stamped character is measured using the specularly reflected regular light 805, when the V-shaped stamped character having no bottom surface is stamped by the worn stamping head, the slit light 803 is generated. The regular reflected light 805 cannot be acquired by the camera 806 because it is not reflected by the groove bottom surface of the stamped character. As a result, there is a problem that measurement becomes impossible.

  Further, when the marking surface 802 is mirror-like, the specularly reflected light 805 specularly reflected by the marking surface 802 becomes thick when input to the camera 806, and there is a possibility that the measurement accuracy may deteriorate.

  The present invention has been made in view of such a conventional problem, and can shorten the measurement time and enable the depth measurement of a stamped character formed in a V-shaped groove or a U-shaped groove shape. At the same time, it is an object of the present invention to provide a marking inspection apparatus that has little influence on measurement accuracy even with a mirror-reflected marking surface.

  In order to solve the above-mentioned problem, in the marking inspection apparatus according to claim 1 of the present invention, in the marking inspection apparatus for inspecting the inspected character stamped on the marking surface, along the character string direction of the inspected character. A plurality of laser slit light sources that are arranged in parallel and irradiate line-shaped slit light extending in the character string direction with respect to the marking surface including the character to be inspected, and provided corresponding to each of the laser slit light sources. A camera that images the irradiation position of the slit light emitted from a corresponding laser slit light source, a moving stage that moves each laser slit light source and camera in an orthogonal direction perpendicular to the character string direction, and each camera A processing device that obtains the height from the slit light position of the captured slit light image and obtains the three-dimensional information of the marking surface, With shifting the timing, in synchronism with the irradiation timing of the slit light from the camera imaging timing and the laser slit light source in correspondence.

  That is, when inspecting the inspected character engraved on the engraved surface, the character is arranged on the engraved surface including the inspected character from a laser slit light source arranged in parallel along the character string direction of the inspected character. While irradiating line-shaped slit light extending in the column direction and imaging the position of irradiation of slit light from the corresponding laser slit light source by a camera provided corresponding to each of the laser slit light sources, Each laser slit light source is moved in the orthogonal direction orthogonal to the character string direction by the moving stage.

  Thereby, the inspected characters arranged in the character string direction are simultaneously scanned and inspected by a plurality of cameras. Therefore, the measurement time can be shortened.

  In addition, the imaging timings of the adjacent cameras are set so as to be shifted, and the imaging timings of the cameras having a corresponding relationship and the irradiation timing of the slit light from the laser slit light source are configured to be synchronized.

  For this reason, interference such as reflection of slit light from the laser slit light source corresponding to the adjacent camera is prevented.

  In the marking inspection apparatus according to claim 2 of the present invention, in the marking inspection apparatus for inspecting a character to be inspected on a marking surface, a plurality of the marking inspection devices are arranged in parallel along a character string direction of the character to be inspected. A laser slit light source that irradiates the slit surface including the inspection character with a line-shaped slit light extending in the character string direction, and a laser slit light source provided corresponding to each of the laser slit light sources. A fixed camera that images the irradiation position of the irradiated slit light, a moving stage that moves each laser slit light source in an orthogonal direction orthogonal to the character string direction, and each camera while moving the slit light The moving stage position that gives the maximum luminance is obtained for each pixel of the image captured in step (3), and the three-dimensional information on the marking surface is obtained based on the stage position and the pixel position. Comprising a processing unit Tokusuru, and with shifting the image capturing timing in the adjacent camera, synchronized with the irradiation timing of the slit light from the camera imaging timing and the laser slit light source in correspondence.

  According to this method, even when the reflected light of the laser, such as the groove bottom, is weak, the luminance when the laser hits is surely higher than the luminance when the laser is not irradiated. Therefore, by obtaining the stage position having the maximum luminance at each pixel in the image and obtaining the height from the position, the height can be measured even with weak reflected light. For this reason, even if it is a case where the to-be-inspected character is formed with a V-shaped groove or a U-shaped groove and regular reflection light from the groove bottom surface cannot be obtained, measurement is possible.

  In addition, the imaging timings of the adjacent cameras are set so as to be shifted, and the imaging timings of the cameras having a corresponding relationship and the irradiation timing of the slit light from the laser slit light source are configured to be synchronized.

  For this reason, interference such as reflection of slit light from the laser slit light source corresponding to the adjacent camera is prevented.

  In the marking inspection apparatus according to claim 3, the laser slit light sources are arranged on one side of the orthogonal direction with the character to be inspected as a boundary, and the cameras are arranged on the other side, while the slit light The positions of the laser slit light sources are shifted in the character string direction with respect to the corresponding camera so that the regular reflected light does not directly enter the field of view of the corresponding camera.

  That is, each laser slit light source is disposed on one side with the character to be inspected as a boundary, and each camera is disposed on the other side. Each camera is arranged so as to be shifted in the character string direction with respect to the corresponding laser slit light source, and the regular reflection light of the slit light from each laser slit light source does not directly enter the field of view of the corresponding camera. It is configured as follows.

  For this reason, even if the said marking surface is mirror-like, the influence which it has on measurement accuracy is suppressed.

  As described above, in the marking inspection apparatus according to claim 1 and claim 2 of the present invention, each laser slit light source is moved in an orthogonal direction orthogonal to the character string direction on the moving stage. The scanning time can be shortened as compared with the case where the character to be inspected is moved by scanning in the direction of the character string. Further, the inspected characters arranged in the direction of the character string can be inspected at a time by a plurality of cameras.

  For this reason, even when the number of arranged characters is large, the inspection time can be shortened.

  In addition, the setting is made so that the imaging timings of the adjacent cameras are shifted, and the imaging timing of the cameras in correspondence with each other is synchronized with the irradiation timing of the slit light from the laser slit light source. It is possible to reliably eliminate erroneous measurement due to interference of slit light from the laser slit light source.

  In particular, in the marking inspection apparatus according to claim 2, a camera is fixed, a plurality of images are captured by each camera while moving a laser slit light source on a moving stage, and a plurality of images are obtained at each pixel (one xy). The moving stage position (corresponding to the time or Y position) having the maximum luminance is obtained in the image of the sheet (the stage position is different because the time is different), and the marking is performed based on the stage position and the pixel position (xy coordinates). The 3D information of the surface was acquired.

  Therefore, it is possible to measure the depth of a V-shaped groove or a U-shaped groove-shaped engraved character, and it is possible to reduce the measurement time and the measurement time even if the engraved surface is mirror-reflected. It can be a stamp inspection device.

  Further, in the marking inspection apparatus according to claim 3, the respective laser slit light sources are arranged so as to be shifted in the character string direction with respect to the corresponding cameras, whereby the regular reflection light of the slit light from each of the laser slit light sources. Can be prevented from entering directly into the field of view of the corresponding camera.

  For this reason, the slit light reflected regularly on the marking surface becomes thicker when it is input to the camera and the measurement accuracy deteriorates. Can be increased.

  Thereby, even if the said marking surface is mirror surface shape, the influence which it has on measurement accuracy can be prevented.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a marking inspection apparatus 1 according to the present embodiment. The marking inspection apparatus 1 is an apparatus for inspecting a character 3 to be inspected that is imprinted on a flat marking surface 2, and an example thereof is an inspection of a strip-shaped plate on which a chassis number is imprinted.

  The work 11 made of this plate is made of a rectangular metal plate, and the inspected character 3 made up of the chassis number is stamped on the marking surface 2 thereof. A plurality of characters 3 to be inspected are arranged in the length direction of the workpiece 11, and each character 3 to be inspected is formed by a groove stamped by a marking head. This groove usually has a flat bottom surface, but may be formed in a V-shaped or U-shaped cross-section without a bottom surface when stamped with a worn marking head.

  The marking inspection apparatus 1 includes first to fifth laser slit light sources 41 to 45 that irradiate the slit light 31 obliquely from above the marking surface 2 of the workpiece 11 placed on the placement table 21. The slit lights 31,... From the laser slit light sources 41 to 45 are in the direction of the character strings of the inspected characters 3,... With respect to the marking surface 2 including the inspected characters 3,. It is configured to irradiate in a line extending in a certain X direction 51. The laser slit light sources 41 to 45 are juxtaposed in the X direction 51 and configured to simultaneously irradiate the plurality of characters to be inspected 3,... Arranged in the X direction 51.

  Each of the laser slit light sources 41 to 45 is composed of first to fifth laser devices 61 to 65 and a light shielding plate 66 that passes the laser slit light 31 from the laser devices 61 to 65. As shown in FIG. 2, the slit light beams 31,... From the laser devices 61 to 65 pass through an opening 67 provided in the light shielding plate 66 and are applied to the marking surface 2. It is configured.

  Further, as shown in FIG. 1, the marking inspection apparatus 1 is provided with a scanning unit 71, and the scanning unit 71 moves the moving stage 72 in the Y direction that is orthogonal to the character string direction. 73 to move to 73. The laser devices 61 to 65 and the light shielding plate 66 constituting the laser slit light sources 41 to 45 are supported by the moving stage 72, and the laser slit light sources 41 to 45 are supported by the scanning unit 71. It is configured to move in the Y direction 73.

  The marking inspection apparatus 1 includes first to fifth CCD cameras 81 to 85 provided corresponding to the laser slit light sources 41 to 45, and the CCD cameras 81 to 85 correspond to the corresponding laser slits. .. Are fixed to the marking inspection apparatus 1 or fixed to the moving stage 72 so that the irradiation positions of the slit light beams 31... Irradiated from the light sources 41 to 45 can be imaged obliquely from above.

  Each of the laser slit light sources 41 to 45 is disposed on one side (upper side in FIG. 1) of the Y direction 73 with the character to be inspected 3,. Are arranged on the other side (lower side in FIG. 1) of the Y direction 73 with the character to be inspected 3,.

  As shown in FIG. 2, the laser slit light sources 41 to 45 and the CCD cameras 81 to 85 correspond to the CCD camera 81 corresponding to the specularly reflected light 91 of the slit light 31 that is specularly reflected by the marking surface 2. The relationship between the corresponding laser slit light sources 41 to 45 and the CCD cameras 81 to 85 is set so as not to be directly input to .about.85.

  That is, as shown in FIG. 2, the CCD cameras 81 to 85 are arranged at positions shifted in the X direction 51 with respect to the corresponding laser slit light sources 41 to 45. ˜45 are configured to irradiate the slit light beams 31,... Obliquely from above toward the field of view of the corresponding CCD cameras 81 to 85.

  At this time, as shown in FIG. 4A, each of the CCD cameras 81 to 85 is configured to be able to move and be fixed slightly in the X direction 51, as shown in FIG. 4B. As described above, the slit light beams 31 to 45 from the adjacent laser slit light sources 41 to 45 that have passed through the light shielding plate 66 have the arrangement of the laser slit light sources 41 to 45 or the The length of the opening 67 of the light shielding plate 66 is set. Therefore, the regular reflection light 91 is not directly input to the CCD cameras 81 to 85.

  As shown in FIG. 3, the angle α formed by the slit light 31 from the laser slit light sources 41 to 45 and the marking surface 2, the optical axes of the CCD cameras 81 to 85, and the The directions of the laser devices 61 to 65 of the laser slit light sources 41 to 45 and the directions of the CCD cameras 81 to 85 are set so that the angle β formed by the marking surface 2 is different.

  As shown in FIG. 1, the marking inspection apparatus 1 includes a control device 101 that also serves as an image processing device configured by a personal computer or the like, and the control device 101 includes the first to first components. The laser devices 61 to 65 of the 5 laser slit light sources 41 to 45, the scanning unit 71, and the CCD cameras 81 to 85 are connected.

  Thereby, when the control device 101 operates according to the program, the scanning unit 71 moves the laser slit light sources 41 to 45 and the slit light beams 31 to 45 from the laser slit light sources 41 to 45. Irradiation and imaging by the CCD cameras 81 to 85 can be controlled. At this time, the imaging timings of the adjacent CCD cameras 81 to 85 are set so as to deviate from each other. The imaging timings of the CCD cameras 81 to 85 and the slit light beams 31 to 45 from the laser slit light sources 41 to 45 are in a corresponding relationship. ··· The irradiation timing is configured to be synchronized.

  FIG. 5 is a timing chart showing the camera imaging timing, and in the upper stage, irradiation of the slit light beams 31,... From the first laser slit light source 41, the third laser slit light source 43, and the fifth laser slit light source 45. Timing 111, shutter timing 112 of the first CCD camera 81, third CCD camera 83, and fifth CCD camera 85, external synchronization signal VD113 for synchronizing the shutter timing 112 and the irradiation timing 111, the first CCD camera 81, Input of imaging data from the third CCD camera 83 and the fifth CCD camera 85 and processing timing 114 are shown.

  In the lower part of this timing chart, the irradiation timing 121 of the slit lights 31 and 31 from the second laser slit light source 42 and the fourth laser slit light source 44, the shutter timing 122 of the second CCD camera 82 and the fourth CCD camera 84, An external synchronization signal VD123 for synchronizing the shutter timing 122 and the irradiation timing 121, and input and processing timing 124 of imaging data from the second CCD camera 82 and the fourth CCD camera 84 are shown.

  As can be seen from this figure, at the shutter timing 112 of the first CCD camera 81, the third CCD camera 83, and the fifth CCD camera 85, the first laser slit light source 41, the third laser slit light source 43, and the fifth laser slit light source 45 Are only illuminated, and the slit light 31 from the first laser slit light source 41, the slit light 31 from the third laser slit light source 43, and the slit light from the fifth laser slit light source 45 are illuminated. Only 31 is input.

  At the shutter timing 112 of the first CCD camera 81, the third CCD camera 83, and the fifth CCD camera 85, the slit lights 31, 31 are not emitted from the second laser slit light source 42 and the fourth laser slit light source 44. Are not input.

  On the other hand, at the shutter timing 122 of the second CCD camera 82 and the fourth CCD camera 84, only the slit lights 31, 31 from the second laser slit light source 42 and the fourth laser slit light source 44 are illuminated, and the second laser is illuminated. Only the slit light 31 from the slit light source 42 and the slit light 31 from the fourth laser slit light source 44 are input.

  At the shutter timing 122 of the second CCD camera 82 and the fourth CCD camera 84, the first laser slit light source 41, the third laser slit light source 43, and the fifth laser slit light source 45 emit the slit light 31,. There is no input of the slit lights 31,.

  Further, the control device 101 is configured to perform image processing of images captured by the CCD cameras 81 to 85.

  There are two possible image processing methods.

  The first method is a method in a configuration in which the cameras 81 to 85 are moved together with the laser slit light sources 41 to 45 on the moving stage 72.

  In this image processing, several hundred images are input by the CCD cameras 81 to 85 while moving the moving stage 72, and slit light images are acquired. In each slit light image, a slit light coordinate is obtained and converted into a height. Thereby, the three-dimensional information of the marking surface 2 is acquired.

  The second method is a method in a configuration in which the cameras 81 to 85 are fixed and only the laser slit light sources 41 to 45 are moved by the moving stage 72.

  In this image processing, several hundred images are input by the CCD cameras 81 to 85 while moving the moving stage 72, and slit light images are acquired. The moving stage position (corresponding to the time or stage Y position) having the maximum luminance in the image of several hundred images (the stage position is different because the time is different) is obtained for each pixel (one xy), and the stage position and Based on the pixel position (xy coordinates), the height is converted into the marking height. Thereby, the three-dimensional information of the marking surface 2 is acquired.

  Then, based on this three-dimensional information, the shape of the character to be inspected 3,... Is obtained, and compared with the master data stored in advance. It can be inspected.

  In the above configuration, when inspecting the inspected characters 3,... Imprinted on the marking surface 2 of the workpiece 11, along the X direction 51 which is the character string direction of the inspected characters 3,. Are irradiated side by side with the slit light sources 41 to 45, which are irradiated with line-shaped slit light beams 31,. In addition, the CCD camera 81 to 85 provided corresponding to each of the laser slit light sources 41 to 45 captures the irradiation position of the slit light 31 from the corresponding laser slit light sources 41 to 45. However, the laser slit light sources 41 to 45 are moved in the Y direction 73 that is orthogonal to the character string direction by the moving stage 72 of the scanning unit 71.

  Thus, the inspected characters 3... Arranged in the X direction 51 can be simultaneously scanned and inspected by the first to fifth CCD cameras 81 to 85.

  For this reason, compared with the case where each said laser slit light sources 41-45 and each said CCD camera 81-85 are moved to the X direction 51 which is a character string direction, and the said to-be-inspected character 3, ... is scanned, The scanning time can be shortened. Further, the inspected characters 3,... Arranged in the character string direction can be inspected at a time by the first to fifth CCD cameras 81-85.

  Therefore, even when the number of arranged characters is large, the inspection time can be shortened.

  In the second image processing method, the height based on the stage position where the luminance is maximum in each pixel is obtained, and the three-dimensional information of the marking surface 2 is acquired. 3,... Are formed by V-shaped grooves or U-shaped grooves, and even if it is not possible to obtain regular reflection light from the bottom surface of the groove, it is possible to measure the depth of the inspected characters 3,. .

  Because even if the reflected light of the laser is weak, the brightness at the time of the laser hit is certainly higher than the brightness at the time when the laser is not irradiated, so each pixel in the image If the stage position with the maximum brightness is found and the height is found from that position, the height can be measured even with weak reflected light (that is, even if the maximum brightness is weak). is there.

  Thereby, even the inspected characters 3,... Imprinted with the engraving head worn by long-term use can be inspected.

  In addition, the imaging timings 112 and 122 of the adjacent CCD cameras 81 to 85 are set so as to be shifted, and the imaging timings 112 and 122 of the CCD cameras 81 to 85 and the slits from the laser slit light sources 41 to 45 are in a corresponding relationship. By synchronizing the irradiation timings 111 and 121 of the lights 31 and so on, the slit lights 31 and so on from the laser slit light sources 41 to 45 corresponding to the adjacent CCD cameras 81 to 85 are imaged. It is possible to reliably eliminate erroneous measurement caused by such interference.

  In the marking inspection apparatus 1, the CCD cameras 81 to 85 are arranged so as to be shifted from the corresponding laser slit light sources 41 to 45 in the X direction 51 that is the character string direction. The specularly reflected light 91,... Of the slit light 31,... From the slit light sources 41-45 can be prevented from directly entering the field of view of the corresponding CCD cameras 81-85.

  For this reason, it is unnecessary compared with the conventional technique in which each slit light 31,... Specularly reflected by the engraving surface 2 becomes thicker when the CCD cameras 81 to 85 are input to the CCD camera 81 to 85, and the measurement accuracy deteriorates. It is possible to eliminate problems such as taking in a large amount of light and increase the inspection accuracy.

  Thereby, even if the said marking surface 2 is mirror surface shape, the influence which it has on measurement accuracy can be prevented.

It is a figure which shows one embodiment of this invention. It is explanatory drawing which shows the principal part of the embodiment. It is explanatory drawing which shows the other principal part of the embodiment. (A) is explanatory drawing which shows each CCD camera of the embodiment, (b) is explanatory drawing which shows each laser slit light source. It is a timing chart which shows the camera imaging timing of the embodiment. It is a figure which shows the conventional marking inspection apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Marking inspection apparatus 2 Marking surface 3 Character to be inspected 31 Slit light 41 1st laser slit light source 42 2nd laser slit light source 43 3rd laser slit light source 44 4th laser slit light source 45 5th laser slit light source 51 X direction 72 Moving stage 73 Y direction 81 1st CCD camera 82 2nd CCD camera 83 3rd CCD camera 84 4th CCD camera 85 5th CCD camera 91 Regular reflection light 101 Control device

Claims (3)

In a marking inspection device that inspects characters to be inspected on the marking surface,
A plurality of laser slit light sources that are arranged in parallel along the character string direction of the character to be inspected and irradiate the slit surface including the character to be inspected with a line-shaped slit light extending in the character string direction;
A camera that is provided corresponding to each of the laser slit light sources, and that captures the irradiation position of the slit light irradiated from the corresponding laser slit light source,
A moving stage for moving each laser slit light source and camera in an orthogonal direction orthogonal to the character string direction;
A processing device that obtains the three-dimensional information of the marking surface by obtaining the height from the slit light image of the slit light imaged by each camera, and
An engraving inspection apparatus characterized in that the imaging timing of adjacent cameras is shifted, and the imaging timing of cameras in correspondence with each other is synchronized with the irradiation timing of the slit light from a laser slit light source. In a marking inspection device that inspects characters to be inspected on the marking surface,
A plurality of laser slit light sources that are arranged in parallel along the character string direction of the character to be inspected and irradiate the slit surface including the character to be inspected with a line-shaped slit light extending in the character string direction;
A fixed camera that is provided corresponding to each of the laser slit light sources and images the irradiation position of the slit light irradiated from the corresponding laser slit light source,
A moving stage for moving each laser slit light source in an orthogonal direction orthogonal to the character string direction;
The moving stage position that gives the maximum brightness is obtained for each pixel of the image captured by each camera while moving the slit light, and the three-dimensional information on the marking surface is obtained based on the stage position and the pixel position. And a processing device for
An engraving inspection apparatus characterized in that the imaging timing of adjacent cameras is shifted, and the imaging timing of cameras in correspondence with each other is synchronized with the irradiation timing of the slit light from a laser slit light source. While arranging each laser slit light source on one side of the orthogonal direction with the character to be inspected as a boundary, and arranging each camera on the other side,
The arrangement position of each laser slit light source is shifted in the character string direction with respect to the corresponding camera so that the specularly reflected light of the slit light does not directly enter the field of view of the corresponding camera. The marking inspection apparatus according to claim 1 or claim 2.

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