JP2006234465A - Visual inspection device and visual inspection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for correcting a deteriorated image generated, after specular reflection is generated, at imaging of inspection image for visually inspecting a printed circuit board. <P>SOLUTION: This device is provided with a sensor part 1 for scanning a light beam polarized by a polygon mirror 3 along an S-axial direction on an inspected object 8, and for receiving the reflected beam by a light-receiving element 7; an image buffer part 17 for storing rectangular image data, obtained by conducting sequentially one-line scans output from the sensor part 1; a mirror face detecting part 22 for outputting a specular reflection generating signal, when the generation of the specular reflection of making the reflected beam of a prescribed light intensity incident into the light receiving element is detected; and a specular reflection part recording part 25 for recording an image data, obtained by scanning an imaging part generated by the specular reflection along a direction reverse to the S-axial direction, and composites the image data from the image buffer part 17 with the image data from the specular reflection part recording part 25, when the specular reflection generating signal for indication the generation of the specular reflection exists. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an appearance inspection apparatus and an appearance inspection method, and more particularly to an appearance inspection that corrects a deteriorated image that occurs after occurrence of specular reflection when an inspection image is captured in a printed circuit board appearance inspection.

  In conventional visual inspection equipment, when specular reflection occurs due to factors such as the material, state, angle, etc. of the light beam and the surface of the inspection object and the positional relationship of the light receiving element when imaging the inspection object, In some cases, light exceeding the processing capacity may suddenly enter. In such a case, the processing speed of the sensor circuit cannot sufficiently catch up, and image deterioration occurs not only in the specular reflection corresponding part but also in the subsequent pixels. In order to avoid excessive incident light on the element, efforts are being made to reduce image degradation even when specular reflection occurs by introducing an ND filter or the like.

  In addition, two illumination devices that can irradiate illumination light from different angles to an inspection object that easily causes specular reflection, and a plurality of imaging devices that are arranged with different viewpoints with respect to the inspection object Prepare and irradiate illumination light sequentially from the two lighting devices, and even if specular reflection occurs, use the fact that the position of the specular reflection on the captured image differs depending on which lighting device is on Thus, a method for removing the influence is disclosed (for example, see Patent Document 1).

  Furthermore, as a method for correcting the generated tailing phenomenon, the degraded pixel region is defined as a pixel between adjacent pixels against the degradation of the image caused by tailing due to the afterglow characteristic when the light emitter emits light. A method is disclosed in which detection is performed from a difference value obtained by comparing values, and correction is performed for each pixel using a correction coefficient based on the difference value at the detection position (see, for example, Patent Document 2).

Furthermore, when there is a strong reflector that reflects ultrasonic waves well in an ultrasonic diagnostic apparatus, the signal level of the received signal becomes higher and may be accompanied by a tail signal, so that the tail signal is attenuated. Extract only the part of the received signal that exceeds the reference voltage, branch it into two, and attenuate the original signal level by multiplying the other received signal by the attenuation control signal generated by inputting one to the integrator. A method for suppressing the level of the trailing signal is disclosed (for example, see Patent Document 3).
JP 2002-260017 A JP-A-7-129964 Japanese Patent Laid-Open No. 7-303014

  However, in the situation where specular reflection occurs, even when electrical measures are taken to insert a clamp diode, sufficient improvements cannot be expected within the specifications of current electronic components such as light receiving elements, amplifiers, and diodes, and ND filters In the case of taking an optical measure to introduce the light, there is a problem that the incident light to the light receiving element at the time of non-specular reflection is also filtered and the dynamic range of the entire image information is reduced.

  Further, in the configuration of the above-mentioned Patent Document 1 that tackles against specular reflection, a plurality of illumination devices and imaging devices are required, so that the capacity of the sensor is increased, and in the printed circuit board visual inspection device, information on the surface of the inspection object Therefore, it is desirable to obtain reflected light information in the vertical direction. However, when the method of Patent Document 1 is used, there is a problem that the reflected light information in the vertical direction cannot be sufficiently obtained. is doing.

  Further, in the above-mentioned Patent Document 2, which has been working on correcting the generated tailing phenomenon, the correction coefficient necessary for correcting the image degradation due to the tailing phenomenon needs to be experimentally obtained and tabulated. Therefore, the printed circuit board appearance inspection apparatus has a problem in that it may be reflected in the variation in inspection accuracy during mass production.

  Furthermore, the configuration of the above-mentioned Patent Document 3 that has worked on correcting the tailing phenomenon in the ultrasonic diagnostic apparatus extracts only the portion exceeding the reference voltage in a series of received signals and multiplies the attenuation control signal to attenuate the original signal level. In order to suppress the level of the trailing signal, there is a problem in the correlation with the signals before and after the trailing generator.

  The present invention solves the above-described conventional problems, and is caused by specular reflection when a light receiving element receives reflected light in a vertical direction with respect to a light beam irradiated from a vertical direction on an object to be inspected. An object of the present invention is to provide an appearance inspection apparatus capable of correcting an inspection image on the basis of data obtained by imaging the inspection object in a state where the inspection object is rotated by 180 degrees against deterioration of the inspection image.

  In order to solve the above-described conventional problems, an appearance inspection apparatus according to the present invention is an appearance inspection apparatus that measures the shape of an inspection object by irradiating the inspection object with a light beam. A sensor unit that scans the deflected light beam in the S-axis direction substantially coincident with the X-axis direction with respect to the inspection object and receives reflected light from the inspection object by a light receiving element, and is output from the sensor unit An image buffer unit for storing strip-shaped image data of the inspection object having a predetermined length in the Y-axis direction obtained by sequentially performing one line scanning in the S-axis direction, and a signal voltage obtained from the reflected light And a reference voltage, and when it is detected that reflected light having a predetermined light intensity or more is incident on the light receiving element, a specular reflection generating signal is output, and based on the specular reflection generating signal Specular reflection A specular reflection unit recording unit that records image data by performing rescanning of the line of the generated imaging position in the direction opposite to the normal S-axis direction, and indicates that the specular reflection has occurred When a reflection generation signal exists, the inspection image is generated by synthesizing the image data from the image buffer unit and the image data from the specular reflection unit recording unit.

  Further, the appearance inspection method of the present invention is an appearance inspection method for measuring the shape of an inspection object by irradiating the inspection object with a light beam. A sensor unit that scans the deflected light beam in a substantially coincident S-axis direction and receives reflected light from the object to be inspected by a light receiving element, and that is output from the sensor unit in the S-axis direction. The strip-shaped image data of the inspection object having a predetermined length in the Y-axis direction obtained by sequentially performing one-line scanning is stored in the image buffer unit, and the signal voltage obtained from the reflected light is compared with the reference voltage. When it is detected that specular reflection occurs when reflected light of a predetermined light intensity or more is incident on the light receiving element, a specular reflection generation signal is output, and the line of the imaging position where the specular reflection has occurred is output based on the specular reflection generation signal. Normal rescan Scanning is performed in the direction opposite to the S-axis direction, image data is recorded in the specular reflection unit recording unit, and when the specular reflection generation signal indicating that the specular reflection has occurred, an image from the image buffer unit is present. The inspection image is generated by combining the data and the image data from the specular reflection unit recording unit.

  According to the appearance inspection apparatus of the present invention, the present invention relates to an apparatus that scans a light beam irradiated from a vertical direction onto an inspection object and detects reflected light incident on a light receiving element to form an image. Two types of light beam scanning directions on the object to be inspected are provided for the deterioration of the inspection image caused by the occurrence of specular reflection when the light receiving element receives the vertical component of light. By performing the correction using the image obtained in (1), it becomes possible to obtain a more precise inspection image.

  In the following, when using the appearance inspection apparatus of the present invention to receive the reflected light in the vertical direction of the light beam irradiated from the vertical direction on the inspection object, it is caused by specular reflection. The inspection image is corrected on the basis of data obtained by imaging in the scanning direction in which the inspection object is rotated 180 degrees in the opposite direction with respect to the normal scanning direction with respect to the deterioration of the inspection image. The details will be described with reference to the drawings.

  FIG. 1 is a flowchart showing a procedure from inspection image capturing to appearance inspection in the appearance inspection apparatus according to the present invention. First, a brief description of each process shown in S1 to S9 in the figure will be given. When a start command for appearance inspection is issued in S1, imaging of the inspection image is performed by receiving, in the inspection image capturing of S2, vertical reflected light from the inspection object of the light beam irradiated from the vertical direction by the light receiving element. Is done. At this time, in S3, specular reflection may occur when the reflection coefficient of the lead portion of the component mounted on the inspection object is large. When specular reflection occurs, the inspection image deteriorates accordingly. Therefore, it is necessary to detect the occurrence of specular reflection and to record the occurrence of specular reflection in order to suppress the deterioration of the appearance inspection accuracy due to the image deterioration. . In S4, the output voltage from the light receiving element is compared with the reference voltage, and a flag signal is output to a dedicated recording unit corresponding to the specular reflection occurrence position. Further, in S5, the scan direction is changed by 180 degrees with respect to the inspected object in which the specular reflection has occurred, and then the range indicated by the flag signal is imaged in S6, and the image data in the range is recorded in S7.

  The image data stored in S7 is read out in the direction opposite to the normal S-axis direction, and is combined with the image data of the portion where the specular reflection is obtained in the imaging in S2.

  Through such steps, it is possible to obtain image data of a specular reflection occurrence portion that minimizes image degradation due to specular reflection. Further, by combining the image data of the part where the specular reflection did not occur and the image data obtained in the procedure of S7 into an inspection image corresponding to the inspection object in S8, a more accurate appearance inspection is performed in S9. It becomes possible to carry out. In the appearance inspection apparatus and the appearance inspection method of the present invention, the above process is performed as one cycle.

  In the following, each step in FIG. 1 will be described in more detail. FIG. 2 schematically shows the configuration of the sensor unit, and FIG. 3 schematically shows the overall configuration of the appearance inspection apparatus including the sensor unit.

  First, the structure of the sensor unit will be described with reference to FIG.

  The sensor unit 1 includes a scanning optical system including a light source 2 (laser light source), a polygon mirror 3, and a scanning lens 4, and a light receiving optical system including a half mirror 5, a condensing lens 6, and a light receiving element 7. The scanning optical system deflects the light beam (laser) from the laser light source 2 by the polygon mirror 3 and irradiates the inspection object 8 with the laser from the vertical direction via the scanning lens 4. Further, the laser deflected by the rotation of the polygon mirror 3 sequentially changes the incident position with respect to the scanning lens 4 and sequentially performs one-line scanning on the inspection object 8 to perform imaging. The one-line imaging width is 30 mm, and the scanning direction is the S-axis direction that substantially matches the X-axis direction. One light receiving optical system obtains an image signal of the inspection object 8 by deflecting the reflected light in the vertical direction from the inspection object 8 by the half mirror 5 and condensing it on the light receiving element 7 by the condenser lens 6. .

Next, imaging of each axis driving unit and the inspection object 8 will be described with reference to FIG.
When an instruction to start imaging is output from the CPU 10, the Y-axis position detection unit 9 generates an imaging start desired position arrival signal A2 from the laser scanning position, the position of the inspection object 8, and the Y coordinate of the imaging start desired position of the inspection object 8. Output to the imaging control unit 11. The placement table 12 of the inspection object 8 is moved in the Y-axis direction by a distance necessary for imaging the inspection object 8 by the Y-axis direction driving unit 13.

  On the other hand, the polygon mirror driving unit 14 rotates the polygon mirror 3 in order to scan the deflected laser on the inspection object 8 in the S-axis direction substantially perpendicular to the Y-axis direction. 4 and 5 schematically show the relationship between the polygon mirror 3 and the S-axis imaging start position notification signal A1. In FIG. 4 showing the case where the surface boundary of the polygon mirror 3 is irradiated with the laser, the deflected laser cannot scan the inspection object 8, and the S-axis imaging start position notification signal A1 at this time Corresponds to signal position 1 in FIG.

  However, when the polygon mirror is further rotated and then irradiated with laser, the deflected laser reaches the S-axis imaging start possible position on the inspection object 8 as shown in FIG. At this time, the S-axis position detection unit 15 outputs an S-axis imaging start position notification signal A1 corresponding to the signal position 2 in FIG. As described above, the S-axis imaging start position notification signal A1 is output to the imaging control unit 11 every time the polygon mirror 3 that rotates at an angle at which the laser is irradiated is positioned at the S-axis imaging start possible position. .

  The imaging control unit 11 enters a trigger waiting state when the desired imaging start position arrival signal A2 is input, and one-line imaging is started when the S-axis imaging start position notification signal A1 is input. Here, the placement direction of the inspection object 8 during the normal inspection is referred to as a 0-degree imaging direction, and at this time, the sensor circuit output switching unit 16 selects the image buffer unit 17 side.

  In this apparatus, a polygon mirror 3 having a 12-surface structure and rotating at 40000 rpm is used, and the cycle of the S-axis imaging start position notification signal A1 is 125 μs. The scan width in the S-axis direction (one line imaging width) that can be scanned on one surface of the polygon mirror is 30 mm, and imaging is performed with a resolution of 1500 points, that is, 20 μm, and the reflected light is input to the light receiving element 7 after being sensor Amplification, A / D conversion, and the like are performed by the circuit unit 18 and temporarily stored in the image buffer unit 17. Furthermore, the strip table image data is obtained by moving the mounting table 12 of the inspection object 8 in the Y-axis direction by a predetermined length at a constant speed (resolution 20 μm / 1 line imaging cycle) during imaging execution. When the imaging of one strip-shaped image is completed, the X-axis direction driving unit 19 moves the sensor unit 1 by 30 mm in the X-axis direction substantially perpendicular to the Y-axis direction, and the sensor unit 1 starts imaging again. This operation is repeated until the entire inspection object 8 can be imaged, and after the strip-shaped images are pasted together in the image composition unit 20, the inspection unit 21 inspects the inspection object 8.

  However, as described above, since the laser incident on the light receiving element 7 is reflected light in the vertical direction of the inspection object 8, in a component having a large reflection coefficient such as an IC or a lead portion of a connector arranged on the inspection object 8. Specular reflection occurs depending on the positional relationship between the optical axis and the light receiving element 7. The specular reflection causes sudden and intense incident light to the light receiving element 7, and the light receiving element 7 and the sensor circuit unit 18 are saturated, and the one-line imaging data is specularly reflected from the occurrence of the specular reflection until several pixels later as shown in FIG. 6. Therefore, the inspection unit 21 cannot perform normal inspection and needs to be improved. The deterioration of the image after the occurrence of the specular reflection caused by the specular reflection shown in FIG. 6 is referred to as a tailing phenomenon.

  That is, when specular reflection occurs, the deterioration after the occurrence of the specular reflection becomes a tailing phenomenon, so that the deteriorated portion of the image data after the occurrence becomes long. In order to remove the image data of the portion where the tailing phenomenon occurs, scanning is performed in the direction opposite to the normal S-axis direction, and image data before and after the portion where the specular reflection does not occur is used. Of course, the image data of the portion where the specular reflection occurs cannot be removed and remains deteriorated, but the deteriorated portion of the image data due to the specular reflection can be reduced.

  In addition, instead of generating the S-axis imaging start position notification signal by the S-axis position detection unit 15 every time the polygon mirror 3 reaches the S-axis imaging start possible position, a separate light receiving element for detecting the laser scanning position is provided. It is also possible to generate an S-axis imaging start position notification signal and output it to the imaging control unit 11.

  In this apparatus, the mounting table 12 of the inspection object 8 is moved in the Y-axis direction by a predetermined length to acquire strip-shaped image data, and the sensor unit 1 is further moved in the X-axis direction. The entire inspection object 8 is imaged, but instead, the sensor unit 1 is moved by a predetermined length in the Y-axis direction to acquire strip-shaped image data, and the placement table 12 of the inspection object 8 is further moved to the X-axis. It is also possible to realize imaging of the entire inspection object 8 by moving in the direction.

  Subsequently, the correction when the tailing phenomenon occurs will be described in more detail. When specular reflection occurs, normally, as shown in FIG. 7, a tailing phenomenon caused by specular reflection appears in the traveling direction of one-line imaging, and the inspection image is deteriorated. Here, in order to clearly indicate the positions of the four corners of the strip-shaped image, the letters A to D are given. The mirror surface detection unit 22 compares the intensity of the image signal output from the light receiving element 7 with a reference voltage, and determines that mirror reflection has occurred when the output of the image signal is greater than the reference voltage, as shown in FIG. As described above, the specular reflection occurrence position is recorded by inputting the flag signal (specular reflection occurrence signal) to the specular reflection occurrence recording unit 23 corresponding to the one-line imaging position of the strip-like image in which the specular reflection occurs. Even when specular reflection occurs, the inspection image is picked up until the entire image of the inspection object 8 is completed. When there is specular reflection in addition to the specular reflection portion, one line is obtained each time. The specular reflection occurrence position is recorded in the specular reflection occurrence recording unit 23 corresponding to the imaging position.

After the imaging in the 0 degree imaging direction with respect to the inspection object 8 is completed, when the specular reflection generation signal is recorded in the specular reflection generation recording unit 23, the inspection object 8 in which the specular reflection occurs is taken out from the mounting table 12 180. Then, the image is captured within the range derived by the specular reflection position detection unit 24 from the recording position of the specular reflection occurrence signal. Of course, the entire inspection object 8 may be re-scanned after re-mounting. Here, the direction in which the inspection object 8 is placed on the placement table 12 while being rotated 180 degrees and the imaging is performed is referred to as a 180-degree imaging direction. Here, the size of the inspection object 8 is X (mm) × Y (mm), the margin from the end of the inspection object 8 to the imaging start position is A (mm) in the X-axis direction, and B ( mm), the position where the specular reflection occurs is counted from the imaging start position and detected at the y-th line constituting the xth strip-shaped image, and given coordinates as shown in FIG. 1 line imaging width is 30 (mm) and the resolution in the Y-axis direction is 20 (μm).
a (mm) = 30 (x−1) + A to 30x + A (1)
b (μm) = 20 (y−1) + B to 20y + B (2)
It becomes clear that the specular reflection occurrence position exists within the range of. Furthermore, the imaging range of the inspection object 8 by the 180-degree imaging direction is
A ′ (MM) = X− (30X + A) to X− {30 (X−1) + A} (3)
B ′ (μM) = Y− (20Y + B) to Y− {20 (Y−1) + B} (4)
It can be expressed as When the imaging command is output from the CPU 10, imaging in the range derived by the equations (3) and (4) is performed. Of course, the imaging range in the 180-degree imaging direction can be designated by changing the values of x and y.

  The sensor circuit output switching unit 16 selects the specular reflection unit recording unit 25 side when imaging the inspection object 8 in the 180-degree imaging direction, and remains in the direction opposite to that when the pixel array is in the 0-degree imaging direction. The image data at the time of 180-degree imaging is recorded in the specular reflection unit recording unit 25. FIG. 10 is obtained by adding the letters A to D to the strip-like image of FIG. 7 taken in the 180-degree imaging direction, and the positions indicated by the letters A to D are shown in FIGS. It is assumed that 10 corresponds. As can be seen from FIG. 10, in the imaging in the 180 degree imaging direction, the tailing phenomenon appears in the traveling direction of the one-line imaging with respect to the specular reflection generation unit. Therefore, the pixel portion affected by the tailing phenomenon in the 0 degree imaging direction. Therefore, it is possible to obtain accurate pixel information that is not affected by the tailing phenomenon. Of course, even in the 180 degree imaging direction, it can be predicted that specular reflection will occur in the same part as the specular reflection part in the 0 degree imaging direction, but the tailing phenomenon caused by the specular reflection occurs in the traveling direction of one line imaging. Therefore, the part where the tailing phenomenon occurs is also different between the 0-degree imaging direction and the 180-degree imaging direction.

  The specular reflection unit recording unit 25, when the H level indicating the occurrence of specular reflection exists in the specular reflection generation recording unit 23 in the strip-shaped image, the entire strip-shaped image data captured in the corresponding 0-degree imaging direction. Reading is performed from the image buffer unit 17. As shown in FIG. 11, the one-line imaging data in the 180-degree imaging direction recorded in the specular reflection unit recording unit 25 is in the opposite direction to the image data in the 0-degree imaging, so that reading in the opposite direction is performed. A strip-like image having less influence of the tailing phenomenon than the strip-like image data including the one-line imaging data in which specular reflection occurs in the 0-degree imaging direction read from the image buffer unit 17 is generated.

  On the other hand, when the H level of the specular reflection occurrence signal does not exist in the strip image, the image composition unit 20 reads the strip image data directly from the image buffer unit 17.

  That is, when there is no specular reflection, the image composition unit 20 reads the image data from the image buffer unit 17 and synthesizes the strip-shaped image. When there is specular reflection, the image composition unit 20 once stores the specular reflection in the specular reflection unit recording unit 25. A strip-shaped image in which specular reflection has occurred is read out, corrected so that the one-line imaging data portion deteriorated by the specular reflection is minimized, and then synthesized by the image synthesis unit 20 with strip-shaped image data that is not affected by the specular reflection. Thus, an inspection image corresponding to the inspection object 8 is obtained. In this case, the entire strip-shaped image may be corrected, or only the line portion where the specular reflection exists may be corrected and combined with the image data by the image combining unit 20.

  In addition, instead of re-mounting the inspection object 8 on the mounting table 12 in a state where the inspection object 8 is rotated 180 degrees, the same image is obtained by rotating the table on which the inspection object 8 is rotated 180 degrees. Is also possible.

  In addition, by rotating the object to be inspected 180 degrees and performing imaging, instead of changing the one-line imaging direction in which the same part is imaged by 180 degrees, the polygon mirror 3 is rotated in the opposite direction to rotate one line. It is also possible to change the imaging direction by 180 degrees.

  Further, the appearance inspection apparatus and the appearance inspection method of the present apparatus are applied to the inspection object instead of the sensor that receives the reflected light in the vertical direction of the laser irradiated from the vertical direction to the inspection object 8 by the light receiving element. It is also possible to carry out with a sensor that receives reflected light of a laser irradiated from a direction having an angle that is not perpendicular to a light receiving element installed in an arbitrary direction.

  When the reflected light in the vertical direction from the inspection object 8 is received by the light receiving element 7 using the appearance inspection apparatus and the appearance inspection method according to the present invention, the tailing phenomenon of the inspection image caused by the specular reflection is caused. On the other hand, it is possible to obtain an inspection image with little influence on the tailing phenomenon by correcting the inspection image based on data obtained by imaging the inspection object 8 in a state of being rotated 180 degrees. As a result, it is possible to obtain a high-accuracy inspection image and to carry out a high-accuracy inspection, and it is possible to further enhance the performance of an appearance inspection apparatus that needs to cope with a printed circuit board whose density is increasing. .

  An appearance inspection apparatus according to the present invention occurs on an inspection object in an appearance inspection apparatus that images the surface state of the inspection object by irradiating the inspection object with a laser and receiving reflected light in the vertical direction. This is useful as a means for correcting a tailing phenomenon caused by specular reflection.

1 is a flowchart showing an imaging method of an appearance inspection apparatus in Embodiment 1 of the present invention. The figure which shows the structure of the optical system of the external appearance inspection apparatus in Example 1 of this invention. The figure which shows the whole structure of the external appearance inspection apparatus in Example 1 of this invention. The figure showing the relationship between the surface of the polygon mirror in a visual inspection apparatus, and an S-axis position detection part output The figure showing the relationship between the surface of the polygon mirror in a visual inspection apparatus, and an S-axis imaging start position notification signal The figure which shows the case where 1 line of the to-be-inspected object which a specular reflection generate | occur | produces by the conventional method is imaged The figure which shows the strip-shaped image which imaged the to-be-inspected object which specular reflection generate | occur | produces in the 0 degree imaging direction in Example 1 of this invention. The figure which shows the recording of the 1 line imaging location where the specular reflection generate | occur | produced in Example 1 of this invention The figure which shows the identification method of the place on the to-be-inspected object which specular reflection generate | occur | produced in the 0 degree imaging direction in Example 1 of this invention. The figure which shows the strip-shaped image which imaged the to-be-inspected object which specular reflection generate | occur | produces in the 180 degree | times imaging direction in Example 1 of this invention. The figure which shows converting 1 line imaging data imaged in the 180 degree | times imaging direction in Example 1 of this invention into 1 line imaging data of 0 degree | times imaging direction.

Explanation of symbols

1 Sensor part 2 Light source (laser)
3 Polygon mirror 7 Light receiving element 8 Inspected object 17 Image buffer unit 22 Mirror surface detection unit 25 Specular reflection unit recording unit

Claims (5)

In the appearance inspection apparatus that measures the shape of the inspection object by irradiating the inspection object with a light beam,
A sensor that deflects a light beam by a polygon mirror, scans the deflected light beam in the S-axis direction substantially coincident with the X-axis direction with respect to the inspection object, and receives reflected light from the inspection object by a light receiving element. And
An image buffer unit for storing strip-shaped image data of the inspection object having a predetermined length in the Y-axis direction obtained by sequentially performing one-line scanning in the S-axis direction output from the sensor unit;
A specular detection unit that compares a signal voltage obtained from the reflected light with a reference voltage and detects that specular reflection occurs when reflected light having a predetermined light intensity or more is incident on the light receiving element; ,
A specular reflection unit recording unit that records image data by performing rescanning of a line at an imaging position where specular reflection has occurred based on the specular reflection generation signal in a direction opposite to the normal S-axis direction;
With
When the specular reflection occurrence signal indicating that the specular reflection has occurred, the inspection data is generated by combining the image data from the image buffer unit and the image data from the specular reflection unit recording unit. A visual inspection device. The appearance inspection apparatus according to claim 1, wherein the image data from the specular reflection unit recording unit is read in a direction opposite to that during recording in the specular reflection unit recording unit. 2. The appearance inspection apparatus according to claim 1, wherein the reverse S-axis scanning scans the inspection object by rotating the polygon mirror in the reverse direction. In the appearance inspection method for measuring the shape of the inspection object by irradiating the inspection object with a light beam,
A sensor that deflects a light beam by a polygon mirror, scans the deflected light beam in the S-axis direction substantially coincident with the X-axis direction with respect to the inspection object, and receives reflected light from the inspection object by a light receiving element. Part
The strip-shaped image data of the inspection object having a predetermined length in the Y-axis direction obtained by sequentially performing the one-line scanning in the S-axis direction output from the sensor unit is stored in the image buffer unit,
A comparison between the signal voltage obtained from the reflected light and a reference voltage is performed, and when it is detected that specular reflection occurs when reflected light having a predetermined light intensity or more is incident on the light receiving element, a specular reflection generation signal is output,
Based on the specular reflection generation signal, rescanning the line at the imaging position where the specular reflection has occurred is scanned in the direction opposite to the normal S-axis direction, and image data is recorded in the specular reflection unit recording unit,
When the specular reflection occurrence signal indicating that the specular reflection has occurred, the inspection data is generated by combining the image data from the image buffer unit and the image data from the specular reflection unit recording unit. Characteristic visual inspection method. 5. The appearance inspection method according to claim 4, wherein the image data from the specular reflection unit recording unit is read in a direction opposite to that when recording to the specular reflection unit recording unit.

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