JP4371883B2 - Illumination light source unit for inspection and surface defect inspection apparatus using the light source unit - Google Patents

Description

  The present invention relates to an inspection illumination light source unit having a plurality of light emitting elements arranged in a predetermined layout pattern, and an output signal from an imaging camera that images a surface to be inspected illuminated by the irradiation light of the inspection illumination unit It is related with the surface defect inspection apparatus provided with the defect evaluation means which evaluates and detects the defect in the said to-be-inspected surface.

  A typical example of this type of inspection apparatus is a technique used for inspecting the painted surface of an automobile body. In such a surface inspection, unevenness, scratches, etc. existing on the painted surface as the surface to be inspected are the inspection objects. As an inspection technique using pattern-shaped inspection light, so-called stripes, that is, illuminating illumination light creating vertical stripes of light and darkness on the painted surface, and imaging the painted surface in an irradiated state with an imaging camera, There is a technique for performing a surface inspection using the obtained captured image. (Technology disclosed in Patent Document 1 and Patent Document 2).

  For example, when the painted surface is moved in a predetermined direction (for example, the X direction), an image portion of a defect such as an uneven surface on the painted surface has coordinates in a direction orthogonal to the moving direction (for example, the Y direction). There is one that detects defects by using the image while changing the direction coordinate (X coordinate) without changing, and in the captured image of the defect area, the light stripe portion is dark and dark stripes. Since the defect is identified using the fact that it is brightly imaged at the part, the defect is captured as an intermediate gradation image of a bright part and a dark part of the stripe (see Patent Document 1).

  In order to detect a defect called "Yuzu skin" that is a periodic unevenness of the surface, it tries to find a group of coating thickness by fluctuation on the captured image of the boundary line of light and dark stripes as inspection light There is a thing (refer patent document 2). In this inspection method, it is not necessary to move the surface to be inspected, but in general, there is a paint surface on which a disturbance that causes displacement in the boundary image of the stripe occurs over a relatively wide range of the paint surface. It becomes a detection target.

JP-A-8-145906 (FIGS. 5, 9, and 15) JP-A-9-126744 (FIG. 13)

  In the above-described conventional surface inspection methods such as Patent Documents 1 and 2, the illumination unit that illuminates the surface to be inspected irradiates the painted surface with a stripe-shaped light / dark pattern, but a highly reliable inspection result is obtained. For this purpose, it is important that the brightness of the bright and dark pattern created by the illumination unit is uniform at a high level at least in the field of view of the imaging camera. However, there arises a problem that the brightness of the light and dark pattern varies within the field of view of the imaging camera depending on the condition of the painted surface that is the surface to be inspected, the imaging angle and surface state of the imaging camera. In addition, when an image is captured using the entire field of view of the imaging camera, there may be a luminance difference that cannot be ignored due to peripheral dimming and lens aberration at the central portion and the peripheral portion.

In particular, in the operation of detecting surface defects while scanning the surface to be inspected by the illumination unit, whether automatically or visually, fluctuations in brightness of the light and dark pattern on the surface to be inspected scanned by the illumination unit are detected as defects. Significant negative impact on reliability.
In view of the above situation, an object of the present invention is to provide an inspection illumination light source unit capable of creating a light and dark pattern as uniform as possible on a surface to be inspected, and a surface defect inspection apparatus using the light source unit. It is.

In order to solve the above-mentioned problems, an illumination light source unit for inspection according to the present invention includes a plurality of light emitting elements arranged continuously so as to repeat a predetermined layout pattern , and a surface to be inspected illuminated by irradiation light of the light emitting elements. configuration and luminance measurement means for obtaining a measured luminance value of the irradiation light of the light emitting element to be reflected, and a light emitting element control unit for controlling the light emission amount of the light emitting element, the brightness measuring means, the brightness measuring means from the The area of the luminescent image corresponding to each light emitting element based on the relationship between the size of the luminescent image on the imaging screen preset for each imaging distance and the coordinate position of each light emitting element based on the output signal from the imaging camera Further, a pixel group corresponding to the region of the emission image is determined, pixel values of pixels included in the pixel group are averaged, and the measurement brightness corresponding to each light emitting element is determined. The light emitting element control means is configured to control the light emission amount of each light emitting element so that the measured luminance value obtained by the luminance measuring means follows a predetermined value. The layout pattern is such that the light emitting elements are continuously arranged in a net shape so as to leave a plate surface of a predetermined shape inside the plurality of light emitting elements, and the plate surface is black or dark is configured, it is arranged such that at least one of said image pickup camera to the plate surface for receiving the illumination light of the respective light emitting element to be reflected from the surface to be inspected.

In this configuration, a measurement luminance value of irradiation light reflected from a surface to be inspected illuminated by a number of light emitting elements arranged continuously so as to repeat a predetermined layout pattern is obtained, and the measurement luminance value is a predetermined value. The amount of light emitted from the light-emitting element is controlled so as to follow the surface of the light-emitting element. The brightness of the reflected reflected light can always be kept constant regardless of the fluctuations in the angle and the peripheral dimming and lens aberrations when using an imaging camera for automatic defect detection. The reliability of the surface defect inspection performed using the pattern can be increased.

In addition, in order to create an efficient light and dark pattern, when the light emitting elements are continuously arranged so as to leave a plate surface of a predetermined shape inside a plurality of light emitting elements , the luminance measurement of irradiation light is performed on one plate surface. By arranging an imaging camera to perform the irradiation, the light emitted from the light emitting element group is reflected by the surface to be inspected and is captured by the imaging camera at a uniform imaging angle. This is convenient for feedback control of the light amount of the element.

Further, as a preferred embodiment of the present invention, the luminance of the light emitted from the light emitting element reflected from a normal normal inspection surface is tabulated as a reference luminance value , and the reference luminance value is obtained by the luminance measuring means . If the light emission amount of each light emitting element is controlled so that the measured luminance value follows, even if there are various test surfaces having different reflection characteristics, etc., each normal test surface Since the brightness of the irradiation light reflected from the table is tabulated as a reference brightness value , it is possible to always create an optimal illumination state for any surface to be inspected by using an appropriate table. .

Furthermore, in order to solve the above-described problems, a surface defect inspection apparatus according to the present invention includes a large number of light emitting elements arranged continuously so as to repeat a predetermined layout pattern, and an object to be inspected illuminated by irradiation light of the light emitting elements. An imaging camera for imaging a surface; defect evaluation means for evaluating an output signal from the imaging camera to detect a defect on the surface to be inspected; and an output light from the imaging camera to evaluate irradiation light of the light emitting element It includes a luminance calculating section for obtaining the measured luminance value of the irradiation light of the light emitting element to be reflected from the test surface which is illuminated, and a light emitting element control unit for controlling the light emission amount of the light emitting element by the brightness calculating section Based on the output signal from the imaging camera, the relationship between the size of the luminescent image on the imaging screen set in advance for each imaging distance and the coordinate position of each light emitting element A region of a light emitting image corresponding to the light emitting element is determined, a pixel group corresponding to the region of the light emitting image is determined, and pixel values of pixels included in the pixel group are averaged to correspond to each light emitting element. And the light emitting element control means controls the light emission amount of each light emitting element so that the measured brightness value obtained by the brightness calculating unit follows a predetermined value. The light emitting elements are continuously arranged in a net shape so that a predetermined shape of the plate surface is left inside the plurality of light emitting elements. The imaging camera is arranged in black or dark color, and the imaging camera is disposed on at least one of the plate surfaces so as to receive irradiation light of each light emitting element reflected from the surface to be inspected.

Since the surface defect inspection apparatus according to this configuration substantially incorporates the above-described inspection illumination light source unit according to the present invention, it is possible to provide all the operational effects of the above-described inspection illumination light source unit. It has a rational configuration that can be used both as an imaging camera for measuring the brightness of reflected illumination light of a light emitting element and an imaging camera for acquiring an image of a surface to be inspected used for detecting a surface defect. Become.
Other features and advantages of the present invention will become apparent from the following description of embodiments using the drawings.

  In FIG. 1, using the illumination light source unit for inspection according to the present invention, a coating surface defect is visually inspected while illuminating the painted surface of the automobile body 1 after the painting process being conveyed to the left by the conveyor 2. The schematic block diagram which shows a form is shown. The inspection illumination light source unit includes an illumination unit 3 that irradiates illumination light as inspection light to a painted surface of an automobile body 1 that is a surface to be inspected, and an imaging camera that images the surface to be inspected illuminated by the illumination unit 3 4 and a controller 5 configured to perform light amount control of the illumination unit 3 using an output signal from the imaging camera 4.

  The imaging camera 4 is assembled to the illumination unit 3 and is suspended from the ceiling so as to be movable by an inspector. The light emitting surface 3a of the illumination unit 3 and the lens surface 4a of the imaging camera 4 serve as the surface to be inspected. Is inspected by the inspector so as to face the painted surface of the automobile body 1 conveyed by.

  As shown in FIG. 2, the illuminating unit 3 has a net-like layout pattern in which a large number of light emitting elements (in this embodiment, LED elements are used and hence referred to as LED elements) 30 leaving a hexagonal space. And it has the structure arrange | positioned continuously (it pinches between the LED elements 30 adjacent) so that this hexagonal layout pattern may be repeated. The space left by the LED elements 30 arranged in a hexagonal mesh shape is referred to herein as a dark surface 31 and is a black or dark plate surface. Although many dark surfaces 31 appear by the LED elements 30 arranged in a net shape, the imaging camera 4 illuminates so that the lens surface 4a of the imaging camera 4 is positioned on the dark surface 31 that is located at the most center among them. Part 3 is incorporated.

  The controller 5 uses a CPU as a core member, and constructs a functional unit for performing various operations of the surface defect inspection apparatus by hardware and / or software. As is apparent from FIG. As a functional unit particularly related to the invention, an input from the imaging camera 4 that takes in an output signal from the imaging camera 4 and develops it in the memory 8 as digital image data (hereinafter simply referred to as an input image) via the image input unit 7. Based on the image, luminance measuring means 70 for measuring the luminance of the irradiation light reflected from the coating surface illuminated by the irradiation light of the LED element 30 of the illuminating unit 3, and the light emitting element measured by the luminance measuring means 70 There is a light emitting element control means 80 for controlling the light emission amount of the LED element 30 so that the luminance of the irradiation light follows a predetermined value.

  The luminance measuring unit 70 includes a luminance calculating unit 71 that calculates the reflection luminance of the irradiation light on the painted surface of each LED element 30 of the illumination unit 3 from the pixel value (luminance value) of the input image read from the memory 8. In accordance with the predetermined coordinate position of each LED element 30 in the input image and the number of pixels in the size of the light emission image which is an image of the reflection point on the painted surface of the light irradiated by each LED element 30 in the input image The luminance value of the light emission image of each LED element 30 is accurately calculated from the averaged pixel values.

  The light emitting element control means 80 is for each painted surface having various painting characteristics that differ depending on the paint color, the painted location, etc., and the brightness of the light emitted from each LED element reflected from the normal painted surface as a reference (pixels of the light emitting image). Value) as a reference luminance in a table and registered in the LUT (look-up table) 82, the calculated luminance value of each LED element 30 calculated by the luminance calculator 71, and the LUT 82. A comparison unit 83 that compares reference luminances for the corresponding LED elements 30 and generates a difference value thereof, and each light emission in the input image based on the difference value of each LED element 30 sent from the comparison unit 83 A light emitting element control unit 84 that determines the power supplied to each LED element 30 of the illumination unit 30 by a PWM control method or the like so that the luminance of the image is a predetermined value, that is, the whole is uniform. There.

  In the illumination light source unit for inspection having the above-described configuration, the light / dark pattern on the painted surface by the irradiation light from the LED elements 30 arranged in a repeated layout pattern of the hexagonal ring that illuminates the painted surface as the surface to be inspected. Has a predetermined uniform luminance distribution over the entire inspection region corresponding to the size of the light emitting surface 3a of the illuminating unit 3, which is convenient for surface defect inspection using a patterned inspection light.

  FIG. 3 shows, as an example of the surface defect inspection apparatus incorporating the inspection illumination light source unit according to the present invention as described above, the painted surface of the automobile body 1 after completion of the painting process which is being conveyed to the left by the conveyor 2. A schematic configuration diagram of an apparatus for inspecting the above is shown. The surface defect inspection apparatus includes an illumination unit 3 that irradiates a painted surface of an automobile body 1 that is an inspection surface with illumination light as inspection light, and an imaging camera 4 that images the inspection surface illuminated by the illumination unit 3. A controller 5 for controlling the light emission amount of the illumination unit 3 using the output signal from the imaging camera 4, evaluating the presence of defects on the surface to be inspected, and outputting the evaluation defects, and an output unit 10 of the controller 5. A monitor 12 and a printer 13 are connected as output devices to be connected.

  In addition to the luminance measuring means 70 and the light emitting element control means 80 described above, the controller 5 in this surface defect inspection apparatus takes in an output signal from the imaging camera 4 via the image input unit 7 and develops it in the memory 8. Defect evaluation means 6 for performing defect evaluation using an input image is provided. Further, the controller 5 is connected to the host computer 14 as a host controller of the surface defect inspection apparatus via the communication unit 11 so as to be able to transmit data. The host computer 14 stores information on the automobile body 1 to be inspected and operation information on the conveyor 2 that are downloaded to the controller 5 as necessary. Further, defect information on the painted surface generated by the controller 5 is also stored. Is also uploaded from the controller 5 to the host computer 14 and stored therein. Further, a projector 15 or a printer controlled by a terminal connected to the host computer 14 via a network is provided in the inspection / verification station, and defect information sent from the controller 5 of the surface defect inspection apparatus via the host computer 14 is included. Based on this, it also has a function to point out the defect location to the inspector.

  The light emitting surface 3a of the illumination unit 3 and the lens surface 4a of the imaging camera 4 that are substantially the same as those shown in FIG. 2 are arranged so as to face the surface to be inspected of the automobile body 1 conveyed by the conveyor 2. If necessary, follow-up control is performed with respect to the surface to be inspected so that the vertical lines of the light emitting surface 3a and the lens surface 4a and the vertical lines of the surface to be inspected are as coincident or parallel as possible.

The illuminating unit 3 has a number of light emitting elements (hereinafter referred to as LED elements since LED elements are used in this embodiment, but in the present invention, the light emitting elements are not limited to LED elements, and other elements may be used depending on the specifications. 30 may be used in a net-like layout pattern that leaves a hexagonal space, and the hexagonal layout pattern is continuously repeated (between adjacent LED elements 30). It has a configuration that is arranged. The space left by the LED elements 30 arranged in a hexagonal mesh shape is referred to herein as a dark surface 31 and is a black or dark plate surface.

  Although many dark surfaces 31 appear by the LED elements 30 arranged in a net shape, the imaging camera 4 illuminates so that the lens surface 4a of the imaging camera 4 is positioned on the dark surface 31 that is located at the most center among them. Part 3 is incorporated. The number of imaging cameras 4 is appropriately determined depending on the size of the light emitting surface 3a of the illumination unit 3.

  The controller 5 uses a CPU as a core member, and constructs a functional unit for performing various operations of the surface defect inspection apparatus by hardware and / or software, as shown in FIGS. 3 and 4. As described above, as a functional unit particularly related to the present invention, in addition to the luminance measuring unit 70 and the light emitting element control unit 80 described above, a preprocessing unit 60A that converts an input image developed in the memory 8 into a form suitable for defect detection. And a defect determination unit 60B that finds a defect on the surface to be inspected using the preprocessed input image.

  The preprocessing unit 60A includes a binarization processing unit 62 that binarizes the input image. The binarization processing unit 62 applies a smoothing filter to the binarization threshold value determination unit 62a for determining the binarization threshold value from the density histogram of the input image by a statistical method and the input image for noise elimination. An image feature extraction unit 62b that applies an edge enhancement filter such as a Sobel filter in order to enhance the outline of a light emission image or a defect image is provided, and image feature extraction is performed using the binarization threshold value determined by the binarization threshold value determination unit 62a. The input image emphasized by the unit 62b is converted into a binarized image.

  An example of the input image binarized by the binarization processing unit 62 is shown in FIG. In this binarized bright and dark image, areas with high luminance are displayed in white, but LED element groups, which are light-emitting images continuously arranged in a hexagonal layout pattern, are continuously connected in a hexagonal shape. Displayed as a white outline, the painted surface area facing the dark surface 31 is displayed as a dark region, and in some cases, an existing coating defect is displayed as a white independent region that floats in the dark region due to diffuse reflection from the surrounding light. Is done. For this reason, in the defect detection, it is only necessary to find an area where luminance is protruding (a white area in this embodiment) and is not continuous in a predetermined pattern, that is, an isolated point in the binarized image. Become. A well-known image processing algorithm for searching for a continuous pixel or an isolated area while having a luminance value (density value) of a predetermined level can be used.

  However, due to the variation of the reflection characteristics with respect to the irradiated light due to the shape of the surface to be inspected here, as shown in an enlarged view in FIG. 6, the light emission image of the LED element 30 that originally appears as a continuous line is interrupted. May occur, and the interrupted portion may be erroneously detected as a defect. The defect determination unit 60B is substantially constituted by a program so as to appropriately avoid such erroneous detection. In other words, the defect determining unit 60B includes a defect candidate extracting unit 63 that detects a discontinuous independent pixel region composed of a predetermined number of pixels as an isolated point to be a defect candidate, and LED elements that are continuously arranged. The defect candidate selection unit 64 that excludes defect candidates included in the region showing the 30 light emission images from the defect candidates, and the unnecessary image regions such as isolated point regions and backgrounds excluded from the defect candidates by the defect candidate selection unit 64 are integrated. Then, an image mask generation unit 65 that performs mask processing as a non-defect determination target region, and a labeling process that assigns different labels (numbers) to different defect candidate regions in order to identify a plurality of defect candidate regions located outside the image mask. Based on the area information from the area calculation unit 67, the label setting unit 66 to be performed, the area calculation unit 67 for calculating the area of each labeled defect candidate area, And a defect determination unit 68 for writing the defect map to determine the candidate true defect. The defect candidate selection unit 64 checks whether or not a defect candidate has been extracted a predetermined number of times from images sequentially sent from the imaging camera 4 in order to select the defect candidate extracted by the defect candidate extraction unit 63. A defect candidate time-series determination unit 64a that prevents a suddenly occurring bright region from being recognized as a defect candidate, and a light emission image in which defect candidates (isolated points) extracted as shown in FIG. 5 are continuous. A light emission image non-continuous portion search unit 64b is provided that prevents the discontinuity of the light emission image from being recognized as a defect candidate by checking whether it is located on the extension line. This search for the non-continuous portion of the luminescent image can be performed using a shape feature extraction algorithm or the like that extracts a dark region located in the extended line region of the discontinuity while tracing the continuous luminescent image pixels, An isolated point existing in this discontinuous region is excluded from defect candidates.

  A defect inspection procedure using the surface defect inspection apparatus configured as described above will be described below with reference to the flowchart of FIG. 7. This defect inspection procedure includes a defect evaluation routine by the defect evaluation means 6 and a luminance measurement means. 70 and the light emission amount control routine for the light emitting element 30 by the light emitting element control means 80 are executed simultaneously.

  In the defect evaluation routine, first, frame images sequentially sent from the imaging camera 4 via the image input unit 7 are taken into the memory 8 (# 02). A binarization threshold value is determined by the binarization threshold value determination unit 62a (# 03) and the image feature extraction unit 62b performs image smoothing and edge enhancement (# 04). The input image is binarized to become a binarized image (# 05).

  From the binarized input image, the defect candidate extraction unit 63 extracts an isolated bright pixel region having the number of pixels within a predetermined number (predetermined from image resolution or the like) as a defect candidate (# 06). . Of the extracted defect candidates, defect candidates belonging to isolated points that are instantaneously and locally generated by disturbance light or the like are excluded from the defect candidates by the defect candidate time-series determination unit 64a (# 07), and further extracted defect candidates. Among these, defect candidates belonging to isolated points located in the discontinuous region of the light emission image are excluded from the defect candidates by the light emission image discontinuous portion searching unit 64b (# 08). The peripheral region including the discontinuous region of the light emission image found by the light emission image discontinuous portion searching unit 64b is the shape information of the vehicle body 1 as the inspection object transmitted from the host computer 14 and the conveyance position information by the conveyor 2 The image mask generation unit 65 performs mask processing as an unnecessary pixel area together with the background area other than the painted surface as the surface to be inspected determined based on (# 09). In this embodiment, since the transport position information obtained from the host computer 14 may be different from the actual position, the positional deviation of the vehicle body 1 in real time is checked using a laser sensor or the like, The position of the image mask is corrected (# 10). After selecting defect candidates and removing the background image in this way, the remaining defect candidates (isolated points) are labeled (# 11), and the area of the isolated points to which each label is assigned is calculated ( # 12) Only isolated points satisfying a preset area condition (whether or not having an area equal to or greater than the threshold) are determined as true defects (# 13), and their coordinate positions and sizes are stored in the defect map. Write (# 14).

  The coating surface defect evaluation routine by the defect evaluation means 6 in steps # 1 to # 14 described above is repeated until the defect inspection is completed, but when all the coating surface defect inspections are completed, this processing routine is completed.

  In the light emission amount control routine for the light emitting element 30 that is executed simultaneously with the defect evaluation routine, first, the input image captured in the memory 8 is (# 02), and the light emission image on the imaging screen set in advance for each imaging distance. The region of the light emission image corresponding to each LED element 30 is determined from the relationship between the LED element 30 and each LED element 30 (# 21), and the pixel group assigned to each LED element 30 is determined (# 22). The luminance calculation unit 71 performs processing steps such as averaging the pixel values (luminance values) of the pixels included in the group to obtain the measured luminance value corresponding to each LED element 30 (# 23). Subsequently, the comparison unit 83 selects a corresponding reference luminance table from the LUT 82, reads a reference luminance value for each LED element 30 (# 24), compares the measured luminance value with the reference luminance value, and obtains a difference value thereof. (# 25). The light emitting element control unit 84 calculates a light emission control amount based on the difference value sent from the comparison unit 83 (# 26), and supplies it to each LED element 30 using the obtained light emission control amount. The power is controlled, and as a result, the light emission amount is controlled (# 27).

  The light emission amount control routine from steps # 20 to # 27 described above is repeated until the defect inspection is completed, but when the defect inspection of all painted surfaces is completed, this processing routine is completed (# 100 Yes branch).

  After that, in the painted surface inspection / verification station, an ID that matches the ID of the automobile body carried into the painted surface inspection / verification station out of the defect map sent from the controller 5 of the surface defect inspection device via the host computer 14. Defect collation is performed using the assigned defect map. At this time, it is advantageous to operate the projector 15 so as to point out the defect location based on the corresponding defect map in order to facilitate the collation work by the inspector. Of course, the defect information based on such a defect map may be output to paper by the printer 13 connected to the output unit of the surface defect inspection apparatus, and the output paper may be directly attached to the automobile body 1.

In the embodiment described above, the illumination unit 3 is configured by the LED element group continuously arranged in a hexagonal mesh shape. However, the mesh shape may be other than the hexagonal shape, and the LED element may be used as the light emitting element 30. Other than these may be adopted .

  In the embodiment described above, each LED element 30 of the illumination unit 3 is controlled by the luminance measurement means 70 and the light emitting element control means 80 so that the amount of light emission is controlled so that the light emission image in the input image has uniform luminance. However, instead of performing feedback control of each LED element 30 independently, the LED elements 30 arranged in the illumination unit 3 may be grouped and feedback controlled in units of groups. In the latter case, there is an advantage that the power control circuit for the LED element 30 is simplified.

The block diagram which shows typically the illumination light source unit for a test | inspection by this invention Schematic diagram showing the illumination unit and imaging camera Configuration diagram schematically showing a surface defect inspection apparatus according to the present invention Functional block diagram showing the configuration of the defect evaluation means mounted on the surface defect inspection apparatus Explanatory drawing explaining the binarized input image Explanatory drawing explaining the isolated point which exists in the discontinuous part of a light emission image Flow chart showing defect evaluation routine and light emission amount control routine executed simultaneously

3: Illumination unit 4: Imaging camera 5: Controller 6: Defect evaluation means 30: Light emitting element (LED element)
31: Dark surface (plate surface)
60A: Pre-processing unit 60B: Defect determining unit 70: Luminance measuring unit 71: Luminance calculating unit 80: Light emission amount controlling unit 81: LUT generating unit 82: LUT
83: Comparison unit 84: Light emitting element control unit

Claims (4)

A number of light emitting elements arranged continuously so as to repeat a predetermined layout pattern , and a luminance for obtaining a measured luminance value of the irradiation light of the light emitting element reflected from a surface to be inspected illuminated by the irradiation light of the light emitting element comprising a measuring means, and a light emitting element control unit for controlling the light emission amount of the light emitting element,
The luminance measuring means is based on an output signal from an imaging camera constituting the luminance measuring means, and the relationship between the size of the light emission image on the imaging screen set in advance for each imaging distance and the coordinate position of each light emitting element To determine a region of a light emission image corresponding to each of the light emitting elements, further determine a pixel group corresponding to the region of the light emission image, and average the pixel values of the pixels included in the pixel group, thereby The light emitting element control unit is configured to obtain the measured luminance value corresponding to an element, and the light emitting element control unit emits light of each light emitting element so that the measured luminance value obtained by the luminance measuring unit follows a predetermined value. Is configured to control
In the layout pattern, the light emitting elements are continuously arranged in a net shape so as to leave a plate surface of a predetermined shape inside the plurality of light emitting elements, and the plate surface is configured in black or dark color. An inspection illumination light source unit, wherein the imaging camera is disposed on at least one plate surface so as to receive irradiation light of each light emitting element reflected from the surface to be inspected. It tabled the brightness of the irradiation light of the light emitting element to be reflected from a normal test surface as a reference as the reference luminance value, so that the measured luminance value determined by the luminance measuring means to the reference luminance value to follow The illumination light source unit for inspection according to claim 1, wherein the light emission amount of each light emitting element is controlled. Evaluating output signals from the imaging camera, a number of light emitting elements arranged continuously so as to repeat a predetermined layout pattern , an imaging camera that images a surface to be inspected illuminated by light emitted from the light emitting element, and Defect evaluation means for detecting defects on the surface to be inspected, evaluation of an output signal from the imaging camera, and irradiation light of the light emitting element reflected from the surface to be inspected illuminated by the light irradiated by the light emitting element includes a luminance calculating section for obtaining the measured luminance value, and a light emitting element control unit for controlling the light emission amount of the light emitting element,
The brightness calculation unit determines whether each light emitting element is based on the relationship between the size of the light emitting image on the imaging screen set in advance for each imaging distance and the coordinate position of each light emitting element, based on the output signal from the imaging camera. The corresponding light emitting image region is determined, the pixel group corresponding to the light emitting image region is determined, the pixel values of the pixels included in the pixel group are averaged, and the measurement corresponding to each light emitting element is performed. It is configured to obtain a luminance value, and the light emitting element control means is configured to control the light emission amount of each light emitting element so that the measured luminance value obtained by the luminance calculating unit follows a predetermined value. Has been
In the layout pattern, the light emitting elements are continuously arranged in a net shape so as to leave a plate surface of a predetermined shape inside the plurality of light emitting elements, and the plate surface is configured in black or dark color. A surface defect inspection apparatus, wherein the imaging camera is arranged on at least one plate surface so as to receive irradiation light of each light emitting element reflected from the surface to be inspected. The brightness of the light emitted from the light emitting element reflected from a normal normal inspection surface is tabulated as a reference brightness value , and the measured brightness value obtained by the brightness calculating unit follows this reference brightness value. The surface defect inspection apparatus according to claim 3, wherein the light emission amount of each light emitting element is controlled.

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