JP2018189562A - Image inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce variations in results of image inspection by reducing a burden on a user related to designation of extraction colors.SOLUTION: An image forming apparatus acquires and displays a spectral image, and receives designation of a region including a plurality of pixels. The image forming apparatus clusters the plurality of pixels included in the designated region, determines representative colors of the clusters, and converts the colors of the pixels forming the spectral image into the representative colors to create a false color image. The image forming apparatus receives designation of extraction colors in the false color image, and creates a gray image on the basis of the distances between the extraction colors and the colors of the pixels of the spectral image of an inspection object. The image forming apparatus executes image inspection by using the gray image.SELECTED DRAWING: Figure 14

Description

  The present invention relates to an image inspection apparatus.

  An image inspection apparatus that inspects an image obtained by imaging a workpiece in order to determine whether or not a product (work) is produced as designed is very useful. In such image inspection, the shape, dimensions, color, etc. of the workpiece are inspected. According to Patent Document 1, a color inspection apparatus that captures color information by imaging an inspection object such as a printed matter and performs color inspection with high accuracy has been proposed.

JP 09-126890 A

  In an image inspection device such as a color inspection device, a user selects a color to be extracted from a color image displayed on a display device by clicking or the like. In order to facilitate user selection, the image inspection apparatus may provide a dropper tool or the like. The image inspection device converts the color image into a gray image (grayscale image) according to the distance between the color selected by the dropper tool and the color of each pixel in the color image, and executes the image inspection of the workpiece using the gray image There are things to do. In addition, the image inspection apparatus may accept the designation by the user of the foreground region including the feature to be image-inspected on the surface of the workpiece and the background region not including such a feature, and extract the colors respectively. . In these cases, since the color of one pixel selected by the user becomes the extracted color, the gray image differs depending on the pixel designated by the user, and the result of the image inspection varies. Accordingly, an object of the present invention is to reduce variations in the results of image inspection by reducing the burden on the user regarding the designation of an extracted color.

The image inspection apparatus of the present invention is, for example,
An acquisition unit for acquiring a spectral image of the inspection object;
A display unit for displaying the spectral image acquired by the acquisition unit;
An area designating unit that accepts designation of an area including a plurality of pixels in the spectral image displayed on the display unit;
Clustering in which each pixel constituting the spectral image belongs to any one of a plurality of clusters according to positions in color space coordinates of a plurality of pixels included in each region specified by the region specifying unit. And
A false color image generating unit that determines a representative color for each of the plurality of clusters and generates a false color image by converting the color of each pixel constituting the spectral image into a representative color of the cluster to which each pixel belongs; ,
An extraction color designation unit that accepts designation of an extraction color to be extracted in the false color image displayed on the display unit;
A conversion unit that converts the spectral image into a gray image based on a distance in a color space between the color of each pixel of the spectral image and the extracted color;
And an inspection unit that performs an image inspection using the gray image generated by the conversion unit.

  According to the present invention, the burden on the user regarding the designation of the extracted color is reduced, and the variation in the results of the image inspection is also reduced.

Diagram showing an image inspection device The figure which shows a lighting device The figure which shows the components which comprise an illuminating device The figure which shows the electrical structure of an illuminating device The figure which shows the function of the image processing system Diagram showing the principle of color tone conversion in multispectral imaging Diagram showing color extraction method by specifying free shape The figure which shows UI which assists the setting of the clustering area The figure which shows UI which assists the setting of the clustering area The figure which shows UI which assists specification of an extraction color The figure which shows UI which assists adjustment of an extraction color The figure which shows UI which assists adjustment of an extraction color The figure which shows UI which assists adjustment of an extraction color Flow chart showing image inspection including color extraction processing The figure which shows the function of the image processing system The figure which shows the function of the image processing system The figure which shows the function of the image processing system

  An embodiment of the present invention is shown below. The individual embodiments described below will help to understand various concepts, such as the superordinate concept, intermediate concept and subordinate concept of the present invention. Further, the technical scope of the present invention is determined by the scope of the claims, and is not limited by the following individual embodiments.

  FIG. 1 is a diagram showing an example of an appearance inspection system (image inspection apparatus 8). A line 1 is a conveyance belt that conveys a workpiece 2 that is an inspection object. The illuminating device 3 is an example of an illuminating unit that has a plurality of light emitting elements that generate inspection light (illumination light) having different wavelengths and irradiates an object with illumination light of each wavelength individually. In order to irradiate the workpiece 2 with illumination light simultaneously or sequentially from a plurality of directions, a plurality of light emitting elements having the same wavelength may be provided. The camera 4 is an example of an imaging unit that receives reflected light from an inspection object illuminated by illumination light and generates a luminance image (spectral image). The image processing device 5 illuminates the inspection target that is the subject of the image inspection by sequentially turning on the light emitting elements with the illumination intensity set for each wavelength, and uses the plurality of inspection images acquired by the imaging unit. An inspection unit that performs image inspection is included. The display unit 7 is a display device that displays a user interface for setting control parameters related to the inspection, an inspection image, and the like. The input unit 6 is a console, a pointing device, a keyboard, or the like, and is used for setting control parameters.

<Configuration of lighting device>
FIG. 2A is a perspective view of the lighting device 3. FIG. 2B is a top view of the lighting device 3. FIG. 2C is a bottom view of the lighting device 3. FIG. 2D is a side view of the lighting device 3. The housing of the lighting device 3 has an upper case 21 and a lower case 22. A light diffusion member 23 for diffusing light output from each of a plurality of light sources (light emitting elements such as LEDs) is disposed below the lower case 22. As shown in FIGS. 2A and 2C, the light diffusion member 23 has an annular shape as in the upper case 21 and the lower case 22. As shown in FIGS. 2B and 2D, a connector 24 is provided on the upper surface of the upper case 21. Connected to the connector 24 is a cable for communication between the illumination control board stored in the illumination device 3 and the image processing device 5. Some functions mounted on the lighting control board may be provided outside the lighting device 3 as a lighting controller. That is, an illumination controller may be interposed between the illumination device 3 and the image processing device 5.

  FIG. 3A is a side view showing the control board 31 and the LED board 32 stored in the lighting device 3. The control board 31 is an example of a second board on which a lighting control unit is mounted. The LED substrate 32 is an example of a first substrate on which a plurality of light sources are mounted. FIG. 3B is a top view of the LED substrate 32. FIG. 3C is an enlarged cross-sectional view of the vicinity of the LED 33 in the illumination device 3. FIG. 3D is a bottom view of the LED substrate 32. FIG. 3E is an enlarged side view of the vicinity of the LED 33 in the LED substrate 32.

  An illumination control board and a connector 24 are disposed on the control board 31. Light emitting elements such as LEDs constituting the light source group are mounted on the LED substrate 32. As shown in FIG. 3B, in this embodiment, four LED substrates 32 are provided to irradiate illumination light from four directions. That is, one LED substrate 32 forms one illumination block. By enabling illumination light from four directions, an image for photometric stereo can be acquired. That is, the illumination device 3 may be used not only for multispectral imaging (MSI) but also for photometric stereo. When four LEDs 33 are arranged on one LED substrate 32, the light source group is composed of 16 light emitting elements. However, a larger number of light emitting elements may be provided. For example, eight LEDs 33 are arranged on one LED substrate 32, and the wavelengths of light emitted by the eight LEDs 33 may be different from each other. As shown in FIGS. 3C, 3 </ b> D, and 3 </ b> E, a light shielding member 35 is disposed between two adjacent LEDs 33 among the plurality of LEDs 33. When a large number of LEDs 33 are arranged closely, illumination light emitted from two adjacent LEDs 33 may pass through the same region of the light diffusion member 23 in some cases. In this case, depending on the lighting pattern, one LED 33 is not lit and the other LED 33 is lit, and the other LED 33 is not lit and one LED 33 is lit. The surface is irradiated with illumination light with the same amount of light from the same illumination direction. This makes it difficult to generate an inspection image with high accuracy. Therefore, by arranging the light shielding member 35 between the two adjacent LEDs 33, a balance between the uniformity of the light amount and the independence of the light source is obtained for the two adjacent LEDs 33. As shown in FIG. 3C, the light emission direction A1 of the LED 33 does not coincide with the main illumination direction A2. Therefore, by arranging the reflecting mirror 34, the light emitted from the LED 33 is deflected in the direction of the light diffusion member 23. Thereby, the light emitted from the LED 33 can be efficiently irradiated onto the workpiece 2. In this example, the emission direction A1 and the reflection direction of the reflecting mirror 34 are substantially perpendicular to each other, but this is because the cross-sectional shape of the light diffusing member 23 forms an arc (FIG. 3C), and the angle ( This is because the central angle is about 90 degrees. By increasing the central angle in this way, it becomes easy to irradiate the surface of the work 2 with substantially uniform parallel light even if the illumination device 3 is moved away from or closer to the work 2. According to the above drawings, the plurality of LEDs 33 are arranged on a certain circumference, but the plurality of LEDs 33 may be arranged on another circumference having different radii. Thereby, since the number of LED33 for every wavelength increases, it becomes possible to increase illumination light quantity. Further, an LED 33 for multispectral imaging may be arranged on the first circumference, and a white LED may be arranged on the second circumference. The radius of the first circumference is different from the radius of the second circumference.

<Circuit configuration of lighting device>
FIG. 4 shows an example of the circuit configuration of the illumination device 3. In this example, one illumination block is shown among the four illumination blocks constituting the light source group. The four LEDs 33a to 33d are connected in series. The variable power supply 41 having a variable voltage generates and outputs a voltage having a voltage value (for example, 2V to 20V) designated by the illumination control board 40. The variable constant current source 42 adjusts the current flowing through the illumination block so that the current value (for example, 0A to 1A) specified by the illumination control board 40 is obtained. By adopting such a current control method, it becomes easy to realize dimming with high linearity. The variable constant current source 42 detects the value of the voltage applied to the variable constant current source 42 and feeds it back to the illumination control board 40 to protect the variable constant current source 42 from overvoltage. A switch 43a to a switch 43d are connected in parallel to each of the LEDs 33a to 33d. The lighting control unit 45 of the illumination control board 40 can individually switch between lighting and non-lighting of the LEDs 33a to 33d by individually opening and closing these switches 43a to 43d. As described above, by connecting the switches 43a to 43d in parallel to the LEDs 33a to 33d, individual lighting such as lighting any one of the LEDs 33a to 33d or lighting all of them can be performed. This is useful for realizing various lighting patterns. The lighting control unit 45 performs lighting control in units of one lighting block by switching on / off a main switch 43e inserted between the variable constant current source 42 and the ground. The communication unit 44 receives a control signal for instructing a lighting pattern and a trigger signal for instructing start of lighting from the illumination control unit of the image processing device 5, and passes them to the lighting control unit 45. The lighting control unit 45 reads the lighting pattern data 47 corresponding to the control signal from the storage unit 46, and controls the switches 43 a to 43 d according to the lighting pattern data 47. In addition, when one illumination block is configured by eight LEDs 33, eight switches 43 are provided, and the eight switches 43 are controlled by the lighting control unit 45. The eight LEDs 33 correspond to, for example, eight wavelengths from UV to IR2. UV indicates a spectral image acquired by illumination light having an ultraviolet wavelength. B shows a spectral image acquired by the blue wavelength illumination light. G indicates a spectral image acquired by illumination light having a green wavelength. AM indicates a spectral image acquired by illumination light having an amber wavelength. OR indicates a spectral image obtained by illumination light having an orange wavelength. R indicates a spectral image acquired by the illumination light having a red wavelength. IR1 and IR2 represent spectral images acquired by illumination light having infrared wavelengths. However, the wavelength of IR1 is shorter than the wavelength of IR2.

<Functional block>
FIG. 5 is a block diagram of the inspection apparatus. In this example, the illumination device 3, the camera 4, and the image processing device 5 are each housed in separate housings, but this is only an example and may be appropriately integrated. The illuminating device 3 is an illuminating device that realizes multispectral imaging. However, the illuminating device 3 may be used as an illuminating unit that illuminates an inspection object according to a photometric stereo method. The illumination apparatus 3 includes a light source group 501 and an illumination control board 40 that controls the light source group 501. As shown in FIG. 3, one illumination block may be configured by a plurality of light emitting elements, and the light source group 501 may be configured by a plurality of illumination blocks. The number of lighting blocks is generally four, but may be three or more. This is because if the work 2 can be irradiated with illumination light from three or more illumination directions, an inspection image can be generated by the photometric stereo method. Each illumination block is provided with a plurality of light emitting elements (LEDs 33) that output illumination light having different wavelengths. The plurality of light emitting elements may include white LEDs. The white LED is not used for multispectral imaging, and is used to create another inspection image or an image for correcting the movement of the work 2. As shown in FIGS. 1 and 3, the outer shape of the illumination device 3 may be ring-shaped. Moreover, the illuminating device 3 may be comprised by the some illumination unit each isolate | separated. The illumination control board 40 controls the lighting timing and illumination pattern (lighting pattern) of the light source group 501 according to the control command received from the image processing device 5. In order to obtain a spectral image by multispectral imaging, the illumination light with an alternatively selected wavelength is irradiated onto the work 2, but when a technique other than multispectral imaging is adopted, illumination light with a plurality of wavelengths is emitted. It may be irradiated at the same time. Although the illumination control board 40 will be described as being built in the lighting device 3, it may be built in the camera 4, or may be built in the image processing device 5, or a housing independent from these. It may be accommodated in.

  The lighting device 3 has a built-in storage device 502, which stores the lighting timing and lighting pattern of the light source group 501 set by the user. The illumination control board 40 can receive the trigger signal from the image processing device 5 and control the light source group 501 in accordance with the contents stored in the storage device 502. With such a configuration, the image processing device 5 can control the illumination device 3 only by transmitting a trigger signal, and therefore the number of signal lines connecting the image processing device 5 and the illumination device 3 can be reduced. And better cable handling.

  The camera 4 is an example of an imaging unit that receives reflected light from an inspection object illuminated by the illumination device 3 and generates a luminance image, and executes an imaging process in accordance with a control command from the image processing device 5. The camera 4 may create a luminance image of the work 2 and transfer it to the image processing device 5, or transfer a luminance signal obtained from the image sensor of the camera 4 to the image processing device 5. May be generated. Since the luminance signal is a signal from which the luminance image is based, the luminance signal is also a luminance image in a broad sense. The camera 4 functions as an imaging unit that receives reflected light from the object for each illumination light of each wavelength output from the illumination device 3 and generates an image (spectral image) of the object.

  The image processing device 5 is a kind of computer, and a processor 510 such as a CPU or ASIC, a storage device 520 such as a RAM, a ROM, or a portable storage medium, an image processing unit 530 such as an ASIC, and a communication such as a network interface. Part 550. The processor 510 is in charge of setting an inspection tool, adjusting control parameters, generating an inspection image, and the like. In particular, the MSI processing unit 511 creates a gray image of the work 2 from a plurality of luminance images (spectral images) acquired by the camera 4 according to multispectral imaging (MSI), or creates an inspection image from the gray image. To do. The gray image itself may be an inspection image. The MSI processing unit 511 may create one color image from a plurality of spectral images. The illumination control unit 512 controls a lighting pattern, illumination switching timing, illumination intensity, and the like by transmitting a control command to the illumination control board 40. The imaging control unit 513 controls the camera 4 according to imaging conditions (exposure time, gain, etc.).

  The UI management unit 514 displays a user interface (UI) for setting an inspection tool, a UI for setting parameters necessary for generating an inspection image, and the like on the display unit 7 and inputs from the input unit 6. Inspection tools and parameters are set according to the information provided. The inspection tool includes a tool for measuring the length of a specific feature (eg pin) of the workpiece 2, a tool for measuring the area of the feature, and a distance from one feature to another feature (eg pin spacing). A tool for measuring, a tool for measuring the number of specific features, a tool for inspecting whether a specific feature is flawed, or the like may be included. In particular, the UI management unit 514 displays a UI for setting control parameters relating to color extraction on the display unit 7. The image selection unit 515 reads the image data of the image selected by the user through the UI from the storage device 520 and displays it in the image display area in the UI. For example, the image selection unit 515 acquires color image data that is a target of color extraction from the storage device 520 through the UI. The area designating unit 516 accepts designation of an inspection tool inspection area IW and the like from the user for the displayed image. In addition, the area designation unit 516 receives designation of a clustered area including a plurality of pixels on which color clustering is performed in the displayed color image. The extraction color designation unit 517 receives designation of an extraction color to be extracted in the false color image displayed on the display unit 7. The extracted color designation unit 517 may include a foreground / background designation unit that accepts designation of at least one of the foreground color that is the color of the foreground area and the background color that is the color of the background area in the false color image. Note that the area designating unit 516 may accept designation of the foreground area and the background area from the user for the displayed image. The foreground area is an area including a feature to be subjected to color extraction in the surface area of the work 2. The background area is an area that exists around the foreground area and does not include a feature to be subjected to color extraction. Note that the foreground area often includes at least a part of the inspection area IW because it includes a feature to be subjected to color extraction. Since areas such as the inspection area, foreground area, and background area are often designated by the user, they may be referred to as designated areas. Further, the area designating unit 516 may accept selection of the shape of these designated areas (eg, rectangle, circle, ellipse, arbitrary shape) and reflect the shape of the frame line indicating the designated area on the UI. The extracted color specifying unit 517 may include an extracted color specifying unit that receives a specification for setting a representative color of any one of a plurality of clusters in the false color image displayed on the display unit 7 as a target color. Good. A cluster is a pixel group composed of a plurality of pixels, and may be called a group. The false color image is an image created from the spectral image and is an image for assisting the user in specifying the extraction color. The cluster number designation unit 518 accepts designation of the number of clusters. The color of each pixel belonging to the clustered area belongs to one of the designated number of clusters. The adjustment unit 519 adjusts at least one of the major axis, the minor axis, and the central coordinates of the distribution surrounding the distribution of the target color projected on the two-dimensional or three-dimensional color space displayed on the display unit 7. Accept according to user instructions.

  The inspection image generation unit 560 generates an inspection image for image inspection from the spectral image of the inspection object (such as the workpiece 2 conveyed on the line 1). The inspection image may be a gray image or an image obtained by further applying image processing (eg, binarization) to the gray image. The inspection image generation unit 560 has various functions. The acquisition unit 561 acquires an image designated by the user through the image selection unit 515 from the storage device 520 or the camera 4. That is, the image selection unit 515 acquires image data through the acquisition unit 561. The clustering unit 562 converts each pixel constituting the spectral image into one of the plurality of clusters according to the position in the color space coordinates of the plurality of pixels included in each region specified by the region specifying unit 516. Make them belong. For example, the clustering unit 562 causes each pixel to belong to one of the clusters using a method such as color clustering. Further, the clustering unit 562 may cause each pixel constituting the spectral image to belong to the number of clusters designated by the cluster number designation unit 518. The false color image generation unit 563 determines a representative color for each of the plurality of clusters, and generates a false color image by converting the color of each pixel constituting the spectral image into the representative color of the cluster to which each pixel belongs. . The conversion unit 564 converts the color information of each pixel of the spectral image into one-dimensional color information based on the distance in the color space between the color of each pixel of the spectral image of the inspection object and the extracted color. Generate an image. For example, the conversion unit 564 may generate an inspection image or a gray image that is the basis of the inspection image by performing color gray conversion. Note that the spectral image to be clustered is generally a spectral image group composed of a plurality of spectral images (eg, UV image, R image, G image, B image, IR image, etc.).

  The UI management unit 514 stores these control parameters set by the user in the setting information 523. The UI management unit 514 may function as a setting unit that sets illumination conditions and imaging conditions, or may function as a setting unit that sets inspection tools.

  The image processing unit 530 includes an inspection unit 531 that performs various measurements by applying an inspection tool to the inspection image. The search unit 532 searches a feature set before the image inspection or a feature dynamically set during the image inspection in the search area SW arranged in the inspection image, and obtains the position of the found feature. The inspection unit 531 corrects the position of the inspection area (measurement area) according to the position of the found feature. The function of the image processing unit 530 may be implemented in the processor 510. Alternatively, the function of the processor 510 may be implemented in the image processing unit 530. Further, the processor 510 and the processor 510 may cooperate to realize a single function or a plurality of functions.

  The determination unit 540 functions as a determination unit that determines the quality of the workpiece 2 using the inspection image. For example, the determination unit 540 receives the result of the inspection performed using the inspection image in the image processing unit 530 and determines whether the inspection result satisfies a non-defective product condition (tolerance or the like).

  The storage device 520 includes spectral image data 521 that is spectral image data acquired by the camera 4, false color image data 522 that is false color image data generated by the false color image generation unit 563, and image data of an inspection image. The inspection image data 524 and setting information 523 for holding various control parameters are stored. The storage device 520 also stores various setting data, a program code for generating a user interface, and the like. The storage device 520 may also store and hold an inspection image generated from a gray image.

  15 to 17 are diagrams showing other configuration examples according to the image processing apparatus of the present invention. FIG. 15 is a diagram illustrating an example in which the illumination device 3 and the camera 4 are integrated, and the camera 4 is provided with an illumination control board 40 for controlling the illumination device 3. In this configuration, since the illumination device 3 and the camera 4 are provided integrally, it is not necessary to align the positions when installing the illumination device 3 and the camera 4. Further, the illumination control board 40 and the storage device 502 for controlling the light source group 501 are not necessary on the illumination device 3 side, and a general-purpose illumination device 3 that does not have these can also be used. The user can remove the lighting device 3 connected to the camera 4 and replace it with another type of lighting device. For example, instead of the illumination device 3 used for multispectral imaging in the present invention, other types of illumination devices such as ring illumination that irradiates only white light can be appropriately selected. It is preferable that the camera 4 recognizes the type of the connected lighting device 3 and reflects it in the setting user interface. Thereby, the user can set illumination on the user interface corresponding to the items that can be set in the connected lighting device 3. As a recognition method, a method in which the illumination device 3 stores illumination type information and the camera 4 refers to the information can be considered. Further, the illumination control unit 512 and the imaging control unit 513 included in the image processing device 5 may be provided inside the camera 4, and the imaging / illumination system may be controlled independently of the image processing device 5. .

  FIG. 16 shows a configuration example in which some functions of the image processing apparatus 5 are provided on the camera 4 side. The camera 4 includes a storage device 520 for storing spectral image data 521, false color image data 522, inspection image data 524, and setting information 523, and processing for generating false color image data 522 from the spectral image data 521 inside the camera 4. Are executed by the MSI processing unit 511, the inspection image generation unit 560, and the like. Also, the inspection image generation unit 560 provided in the camera 4 creates inspection image data 524. The illumination device 3 is controlled by the illumination control unit 512 of the camera 4. At the time of inspection setting, the camera 4 uses the spectral image data 521 captured by the image processing device 4 at each wavelength, false color image data 522 generated by the MSI processing unit 511, and inspection image data created by the inspection image generation unit 560. 524 is transmitted to the image processing apparatus 5. At the time of setting, the image processing apparatus 5 acquires the spectral image data 521 from the camera 4 in order for the user to confirm whether the illumination intensity of each wavelength and the spectral image data 521 of each wavelength are necessary for the inspection, and the display unit 7 is displayed. On the other hand, during the inspection operation, the spectral image data 521 may not be transmitted from the camera 4 to the image processing device 5, and only the inspection image data 524 that is the inspection target may be transmitted to the image processing device 5. In this way, by causing the camera 4 to bear a part of the functions of the image processing device 5, the communication load between the camera 4 and the image processing device 5 is reduced, and the processing speed is increased by distributed processing.

  FIG. 17 shows a configuration example in which all functions of the image processing apparatus 5 are built in the camera 4. Since the user only needs to install the camera 4 and the lighting device 3, it does not take time for installation. For example, this configuration may be advantageous when an increase in the size of the camera 4 is allowed and advanced image calculation processing is not required.

<Multispectral imaging>
In multispectral imaging, illumination light having different lighting colors (wavelengths) is irradiated onto the workpiece 2 one by one in order, and an image (spectral image) for each wavelength is acquired. For example, when illumination light with eight types of wavelengths is irradiated, eight images (spectral images) are acquired. Note that when there are four illumination blocks, the four illumination blocks are lit simultaneously. That is, since the four LEDs 33 having the same wavelength are turned on simultaneously, the illumination light having the same wavelength is irradiated onto the work 2 from the four directions. The eight types of wavelengths are, for example, eight types of narrow band wavelengths from the ultraviolet wavelength to the near infrared wavelength. The narrow band wavelength means a wavelength narrower than the width of the wavelength of light emitted from the white LED (broadband wavelength). For example, the wavelength of the light emitted by the blue LED is much narrower than the wavelength of the light emitted by the white LED, so the wavelength of the light emitted by the blue LED is a narrow band wavelength. It should be noted that some image inspections do not require all eight spectral images. In this case, only the illumination light having a necessary wavelength is irradiated onto the workpiece 2. In general, eight images are rarely used for image inspection as they are, and one gray image is created from the eight images (color shading conversion), and this gray image (color shading image) is used for image inspection. The The color shading conversion is sometimes called color gray conversion. For example, a binarization process, an edge detection process, or a blob process is performed on a color grayscale image, and the position and dimensions (length, Area) and color are checked to see if they are within tolerance.

  An example of color shading conversion will be described with reference to FIG. In order to create a gray image of the work 2 that is the inspection object, a registered color of a good product (model) is required. This is because a gray image is created by converting eight spectral images based on color information of registered colors.

  First, in the setting mode, color information of registered colors is extracted from image regions (designated regions) designated by the user in eight spectral images acquired from non-defective products. For example, when the non-defective product is an instant food (eg, ramen) and the number of certain ingredients (eg, shrimp) is counted by image inspection, the user displays an image of the non-defective product, and the relevant material is displayed in the non-defective image. Is specified, and color information of the registered color is extracted from the pixels included in the specified area. The color information of the registered color includes an average pixel matrix, a variance covariance matrix, and the number of pixels included in the designated area. Note that the color information may be extracted by a so-called dropper tool. The UI of the eyedropper tool may be mounted on the area specifying unit 516.

  Next, in the inspection mode, eight spectral images are acquired for the workpiece 2 that is the inspection object. The distance d (x) with respect to the registered color is obtained for all the pixels included in each spectral image (x is an 8-dimensional vector whose elements are the pixel values of the eight spectral images). Further, the product is obtained by multiplying the distance d (x) by a predetermined gain g, adding the offset a as necessary, and subtracting the product from the maximum gradation Gmax that each pixel can take. G is the gray gradation of the target pixel x. This is expressed as G = Gmax− (g · d (x) + a).

  When there are a plurality of registered colors, a plurality of gray images may be created based on each registered color, or a single gray image may be created.

  The above-described color gray conversion can also be employed when converting a color image such as an RGB image into a gray image. Also in this case, the color information of each pixel is converted into light / dark information based on a certain registered color (color designated by the user), and a gray image is generated. The variance-covariance matrix may be decomposed into a matrix indicating brightness and a matrix indicating chromaticity. In addition, the brightness matrix may be multiplied by a brightness scale (coefficient Sy) for adjusting the brightness matrix. Similarly, the chromaticity matrix may be multiplied by a chromaticity scale (coefficient Sz) for adjusting the chromaticity matrix. These scales may be changed by adjusting the distribution of the extracted colors.

<Specify extraction color>
FIG. 7A shows a color image (example: RGB image) including the feature f on the surface of the work 2. In order for the user to inspect the image of the feature f, first, it is necessary to extract the color of the feature f. Although the color of the feature f may appear to be the same color at any position to the human eye, the pixels constituting the image of the feature f do not necessarily have the exact same color.

  For example, the color of the pixel p1 and the color of the pixel p2 are different. Even if the pixel p1 is selected with the pointer 706 and the color of the pixel p1 is extracted, the pixel p1 is only one of the many pixels constituting the feature f. For this reason, even if the color image of the workpiece 2 is converted into an inspection image such as a gray image based on the color of the pixel p1, the inspection image may not accurately represent the color or shape of the feature f.

  FIG. 7B shows that a free-form area is drawn by the pointer 706 so as to surround almost the entire feature f. The image inspection apparatus 8 obtains an average value of pixel values in a free-form area, and converts a color image into an inspection image based on the average value. Thereby, the dispersion | variation in a test | inspection image becomes small. However, as the shape of the feature f becomes more complicated, the burden on the user to draw a free shape increases.

  Therefore, in the present embodiment, by adopting color extraction by color clustering, the burden on the user is reduced and the variation in the inspection image is reduced.

User Interface for Aiding Color Extraction FIG. 8 shows a UI 800 that the UI management unit 514 displays on the display unit 7 to assist color extraction by the user. The UI 800 has an image display area 801 and setting tabs for performing various settings. In FIG. 8, a clustering tab 810 for setting parameters relating to color clustering (color plane division) is selected. The extraction tab 820 is a tab for assisting color extraction by the user using the clustering result. The adjustment tab 830 is a tab for adjusting the extracted color.

  The image display area 801 is an area for displaying the image selected by the pull-down menu 811. The pull-down menu 811 is a UI for designating a plurality of spectral images stored in the storage device 520, a plurality of spectral images acquired by the camera 4, and the like. Here, a color image or a gray image generated by combining one spectral image or a plurality of spectral images among the plurality of spectral images may be selected.

  An image that is not registered in the pull-down menu 811 can be specified by selecting “Reference” in the pull-down menu 811. The image selection unit 515 displays the image selected by the pull-down menu 811 in the image display area 801. The clustering region 802 is a region having a predetermined shape such as a rectangle, a circle, or an ellipse on which color clustering (classification) is performed. The shape of the clustered region 802 is selected by operating a pull-down menu 812 for the user to select a region shape. An edit button 813 is a button for editing the size (eg, vertical, horizontal, radius, etc.) and position of the clustered area 802. When the edit button 813 is operated, the area specifying unit 516 of the UI management unit 514 receives a change in the size of the clustered area 802 by the pointer 706. A text box 814 receives an input of the number of clusters. The cluster number designating unit 518 receives the numerical value input in the text box 814 as the cluster number. The number of clusters indicates how many colors (clusters) the color in the clustered area 802 is divided into. The clustering button 815 is a button for instructing execution of color clustering for an image surrounded by the clustering region 802. The confirmation button 816 is a button for instructing confirmation of the color extraction result. A cancel button 817 is a button for discarding the color extraction result.

  FIG. 9 shows the UI 800 after color clustering has been performed. When the processor 510 (clustering unit 562) detects that the clustering button 815 is pressed by the pointer 706, the processor 510 (clustering unit 562) analyzes each pixel surrounded by the clustering region 802 and selects one of N clusters designated by the user. Each pixel belongs to the cluster. N is the number of clusters. Further, the processor 510 (the false color image generation unit 563) replaces the color of each pixel in the clustered region 802 in the original spectral image with the representative color of the cluster to which each pixel belongs, and thereby the false color image. Is generated.

  Further, the processor 510 (false color image generation unit 563) updates the image displayed in the clustered area 802 to a false color image. A false color image is an image to which color clustering is applied. If the number of clusters is 2, the color of each pixel in the clustered region 802 is one of the representative color of the first cluster and the representative color of the second cluster. The colors of all the pixels classified into the first cluster are replaced with the representative colors of the first cluster. The colors of all the pixels classified into the second cluster are replaced with the representative colors of the second cluster. As a result, the image in the clustered area 802 is divided into two colors. Since the clustered area 802 is thus divided into a plurality of areas (planes), clustering may be referred to as color plane division.

  In the false color image displayed in the clustered area 802 shown in FIG. 9, the feature f is represented by the representative color of the first cluster, and the periphery of the feature f is represented by the representative color of the second cluster. The representative color of each cluster is an average color, an emphasized average color, an index color, or the like of a plurality of pixels belonging to the cluster. The false color image may be called a divided image, a clustered image, or an index image.

FIG. 10 shows the extraction tab 820. Note that the clustering tab 810 and the extraction tab 820 may be integrated into one tab, but for convenience of explanation, these are described as two tabs. When the UI management unit 514 detects selection of the extraction tab 820 with the pointer 706, the UI management unit 514 displays the content of the extraction tab 820 on the UI 800. A pull-down menu 1011 is a UI for assisting selection of a color extraction method. Here, foreground / background extraction is selected as an example of the color extraction method. Foreground / background extraction refers to extracting the color of the foreground area (foreground color) and the color of the background area (background color). Extracted colors such as the foreground color and background color may be referred to as registered colors. The radio button 1012 is a button for designating which foreground color is registered when there are a plurality of foreground colors. In this example, since there are two foreground radio buttons 1012, a maximum of two foreground colors can be registered. If the number of foreground areas is limited to one, the radio button 1012 is not necessary. The extracted color designation unit 517 determines the color of the pixel designated by the pointer 706 as the foreground color and displays the foreground color in the foreground color display area 1013. The radio button 1014 is a button for designating which background color is registered when there are a plurality of background colors. The extracted color designation unit 517 determines the color of the pixel designated by the pointer 706 as the background color, and displays the background color in the background color display area 1015.

A check box 1016 is a check box for enabling automatic selection of neighboring colors (comparison colors). When the check box 1016 is checked, the processor 510 (extracted color specifying unit 517) selects a background color close to the foreground color in the color space. Note that, when a background color is designated by the user, the processor 510 (extracted color designation unit 517) selects a foreground color close to this background color in the color space. When one background color is designated by the user as described above, the extracted color designation unit 517 designates (selects) one foreground color from the plurality of foreground colors. When one foreground color (specified color) is specified by the user from among a plurality of foreground colors, the extracted color specifying unit 517 selects one background color (neighboring color) closest to the specified color among the plurality of background colors. Specify (select). The neighborhood color is selected in this way because the purpose of adjustment is to separate the target color (foreground color / background color) and the comparison color (background color / foreground color) that are nearby in the color space. .

  The extracted color designation unit 517 may include a neighborhood color determination unit that calculates a neighborhood color (background color / foreground color) for the designated color (foreground color / background color). As a result, the user's burden of specifying neighboring colors is reduced. When the processor 510 (the conversion unit 564) detects that the confirmation button 816 provided on the extraction tab 820 is pressed, the processor 510 (the conversion unit 564) creates an inspection image according to the extracted color. The inspection unit 531 performs an image inspection on the feature f of the workpiece 2.

  11 and 12 are diagrams showing the adjustment tab 830. When the adjustment tab 830 is selected by the pointer 706, the UI management unit 514 displays the contents of the adjustment tab 830 on the UI 800 and displays two images in the image display area 801. The left image is a color image (false color image) that has been subjected to color clustering. The image on the right side is a distribution image indicating the degree of separation between the distribution of the target color and the distribution of the comparative color in the color space of the color image.

  The attention color is a color selected by the radio buttons 1012 and 1014 among the foreground color and the background color. The extracted color designation unit 517 determines a color selected by the radio buttons 1012, 1014 from among a plurality of foreground colors and a plurality of background colors as a target color. The comparison color is a color selected from the false color image by the user operating the pointer 706. When automatic selection of neighboring colors (comparison colors) is enabled, the extraction color designation unit 517 automatically selects a comparison color.

  As described above, the extraction color designation unit 517 may accept designation of a comparison color. In general, the user selects a color to be separated from the target color as a comparison color. For example, in the case where the clustered region 802 is divided into five clusters, the cluster having the closest Euclidean distance in the color space to the cluster including the target color is selected. The processor 510 (extracted color designation unit 517) obtains the distance between the representative color of the cluster including the target color and the representative colors of a plurality of other clusters, and becomes the minimum distance among the obtained distances. Alternatively, a representative color of another cluster may be selected as a comparison color (neighboring color). The distance is, for example, the distance between the center positions (center of gravity positions) of each cluster.

  The processor 510 (the adjustment unit 519 or the inspection image generation unit 560) creates a distribution image by projecting the distribution of the target color and the distribution of the comparison color into a two-dimensional color space. Note that the processor 510 (the adjustment unit 519 or the inspection image generation unit 560) may create a distribution image by projecting the distribution of the target color and the distribution of the comparison color into a three-dimensional color space. Reference numeral 1111 indicates the distribution of the target color. The adjustment unit 519 arranges an elliptical frame 1112 so as to surround the distribution 1111 of the target color. A frame 1112 is a frame whose major axis and minor axis can be changed by a pointer 706. The major axis corresponds to the major axis (brightness axis), and the minor axis corresponds to the minor axis (chromaticity axis). In general, the longest axis among a plurality of axes is called a main axis, and the axis other than the longest axis is called a sub-axis.

  The adjustment unit 519 changes the lightness scale and the chromaticity scale that affect the distribution of the target color in accordance with the change in the size of the frame 1112 by the user.

  Reference numeral 1113 indicates a distribution of comparative colors. The adjustment unit 519 arranges an elliptical frame 1114 so as to surround the comparison color distribution 1113. The oval frame 1114 may be a frame whose major axis and minor axis can be changed by the pointer 706. By changing the size of the frame 1114, the lightness scale and the chromaticity scale that affect the distribution of the comparison colors are changed. Alternatively, the comparison color distribution 1113 may not be changed and may be fixed.

  The adjustment tab 830 is provided with a display area 1121 indicating the target color and a display area 1122 indicating the comparative color. When the UI management unit 514 (comparison color designation unit) detects that a right-click has been made at an arbitrary position in the false color image displayed in the image display area 801, the color (registered color) at that position is used as a comparison color. May be specified. Alternatively, the UI management unit 514 (comparison color designation unit) may select the registered color selected by the radio button as the comparison color. As described above, the UI management unit 514 (comparison color designation unit) may register a color located near the target color in the color space as the comparison color.

  A text box 1123 indicates a scale by which the brightness of the target color is multiplied. The adjustment unit 519 changes the brightness scale of the target color according to the adjustment of the elliptical frame 1112. A text box 1124 indicates a scale by which the chromaticity of the target color is multiplied. The adjustment unit 519 changes the chromaticity scale of the target color in accordance with the adjustment of the elliptical frame 1112. These scales may be linked with the scale of the brightness matrix and the scale of the chromaticity matrix obtained by decomposing the above-described variance-covariance matrix. A text box 1125 indicates the center coordinates of the color distribution of the target color. The user may adjust the center coordinates of the color distribution of the target color by dragging the vicinity of the center of the color distribution of the target color with the pointer 706. The adjustment unit 519 updates the center coordinate of the color distribution of the target color according to the drag amount of the pointer 706 and reflects it in the text box 1125.

  In the example shown in FIG. 11, it can be seen that the target color and the comparative color are sufficiently separated. If the target color is the foreground color and the comparative color is the background color, the feature f is sufficiently separated from the surrounding area by ensuring a sufficient distance (degree of separation) between the foreground color and the background color. An image is created. On the other hand, in the example shown in FIG. 12, the target color (foreground color) and the comparative color (background color) are not sufficiently separated. Therefore, as shown by the dotted line in FIG. 13, when the brightness is changed by adjusting the size of the frame 1112 linked to the distribution of the target color, the color distribution of the target color is changed, and the target color and the comparison color are separated. The extent of In this example, the brightness of the attention color is changed.

Flowchart FIG. 14 is a flowchart showing image inspection including color extraction processing. The processing from S1401 to S1407 can be executed in the setting mode, and the processing from S1408 to S1410 can be executed in the operation mode (inspection mode).

  In S1401, the processor 510 (acquisition unit 561) acquires a color image of the setting object. The acquisition unit 561 sets illumination conditions (light emitting elements to be turned on, illumination intensity, etc.) on the illumination control board 40 through the illumination control unit 512, turns on the light source group 501, and irradiates the setting object with illumination light. The acquisition unit 561 sets an imaging condition (exposure time, aperture, etc.) to the camera 4 through the imaging control unit 513 and instructs imaging. The camera 4 stores the image data of the color image of the setting object in the storage device 520. The processor 510 reads out image data of a color image from the storage device 520. The acquisition unit 561 may acquire a color image designated by the user from the storage device 520.

  In S1402, the processor 510 (area specifying unit 516) receives the specification of the clustered area 802 from the user. The UI management unit 514 displays the UI 800 on the display unit 7 and accepts designation of the clustered area 802. A color image acquired from the storage device 520 is displayed in the image display area 801.

  In S1403, the processor 510 (cluster number designating unit 518) accepts designation of the cluster number N from the user. The cluster number N is a numerical value input in the text box 814. The text box may be another type of control object such as a pull-down menu.

  In S1404, the processor 510 (clustering unit 562) classifies each pixel in the clustered region set in the color image into N clusters. Here, a known color clustering algorithm such as K-means or GMM (Gaussian mixture model) can be employed.

  In step S1405, the processor 510 (a representative color determination unit provided in the clustering unit 562 or the false color image generation unit 563) determines a representative color of each cluster. The representative color is an average color, an emphasized average color, an index color, or the like for the colors of the pixels belonging to each cluster.

  In S1406, the processor 510 (false color image generation unit 563) creates a false color image by converting the color image into a false color image based on the representative color of each cluster. For example, the processor 510 replaces the color of each pixel belonging to a certain cluster with the representative color of that cluster. This replacement process is executed in all clusters.

  In step S1407, the processor 510 (extraction color designation unit 517) accepts designation of a registered color. As shown in FIG. 10 and the like, the UI management unit 514 displays a false color image in the image display area 801, and sets the pixel color (representative color) designated by the pointer 706 as a registered color. Registered colors include one or more foreground colors and one or more background colors. Note that the color extracted by color clustering may be different from the user's intention. In this case, the user may finely adjust the color distribution of the extracted color by opening an adjustment tab 830 as shown in FIGS.

  In S1408, the processor 510 (acquisition unit 561) acquires a color image of the inspection object. The illumination control unit 512 of the processor 510 sets illumination conditions (such as a light emitting element to be turned on and illumination intensity) on the illumination control board 40, turns on the light source group 501, and irradiates the inspection object with illumination light. The imaging control unit 513 of the processor 510 sets imaging conditions (such as exposure time and aperture) in the camera 4 and instructs imaging. The camera 4 stores the image data of the color image of the inspection object in the storage device 520. The processor 510 reads out image data of a color image from the storage device 520.

  In S1409, the processor 510 (conversion unit 564) creates an inspection image based on the registered color and the color image of the inspection object. The inspection image may be different for each inspection tool. For example, the conversion unit 564 may convert the color image into a gray image (foreground image) according to the Mahalanobis distance between the registered color (foreground color) of the foreground region in the color space and the color of each pixel of the color image. The conversion unit 564 may convert the color image into a gray image (background image) according to the Mahalanobis distance between the registered color (background color) of the background region in the color space and the color of each pixel of the color image. These images may be further subjected to further image processing such as binarization. In addition, the processor 510 (the conversion unit 564) may create a difference image between the foreground image and the background image as an inspection image.

  In step S1410, the processor 510 (inspection unit 531) executes an image inspection by applying an inspection tool to the inspection image. As an example, it is assumed that the inspection object is a metal terminal provided on a resin plate, and the area of the metal terminal and the surrounding area are obtained by an area inspection tool provided in the inspection unit 531. The foreground color is the representative color of the metal terminal, and the background color is the representative color of the resin plate. The inspection unit 531 converts the color of the resin plate to white by binarizing the foreground image, converts the color of the metal terminal to black, and calculates the area of the metal terminal by counting the number of black pixels. To do. Similarly, the inspection unit 531 converts the color of the resin plate to black by binarizing the background image, converts the color of the metal terminal to white, and counts the number of black pixels to count the metal terminals. Calculate the area of the surrounding resin plate. The determination unit 540 determines pass / fail by comparing the area of the metal terminal with a threshold value such as tolerance. The determination unit 540 determines pass / fail by comparing the area around the metal terminal with a threshold such as tolerance.

<Summary>
As described above, the acquisition unit 561 and the image selection unit 515 are examples of an acquisition unit that acquires a color image in which each pixel has multidimensional color information. Further, the acquisition unit 561 and the image selection unit 515 are an example of an acquisition unit that acquires a spectral image of an inspection target. The color image is, for example, an image of an inspection object (work 2 conveyed on the line 1) or a setting object (non-defective product or reference product of the work 2), and one spectral image (eg, a plurality of spectral images) : A UV image), or a true color image or a gray image generated by combining a plurality of spectral images. The UI management unit 514 and the display unit 7 are examples of a display unit that displays a spectral image acquired by the acquisition unit 561 and the like. The region designation unit 516 receives designation of a region including a plurality of pixels in the spectral image displayed on the display unit 7. The clustering unit 562 converts each pixel constituting the spectral image into one of the plurality of clusters according to the position in the color space coordinates of the plurality of pixels included in each region specified by the region specifying unit 516. Make them belong. Although only one clustered area 802 is designated in FIG. 8, a plurality of clustered areas 802 may be designated. In this case, the clustering unit 562 performs clustering for each of the plurality of clustered regions 802. The false color image generation unit 563 determines a representative color for each of the plurality of clusters, and generates a false color image by converting the color of each pixel constituting the spectral image into the representative color of the cluster to which each pixel belongs. The representative color may be a color that represents the color of a plurality of pixels constituting the cluster, such as an average color. The extraction color designation unit 517 receives designation of an extraction color to be extracted in the false color image displayed on the display unit 7. The color of each pixel in the cluster in the original color image is often not uniform. For this reason, the extracted color varies depending on which pixel the user selects with the dropper. On the other hand, since the colors of the pixels belonging to the cluster in the false color image are the same, there is no variation in extraction power. The conversion unit 564 converts the color information of each pixel of the spectral image into one-dimensional color information based on the distance in the color space between the color of each pixel of the spectral image of the inspection object and the extracted color. An image (inspection image) is generated. For example, the color information in the RGB color space is converted into color information in a color space of only gray (shading). Depending on the inspection tool, image processing such as binarization processing and edge extraction processing may be additionally executed. The inspection unit 531 performs image inspection using the inspection image generated by the conversion unit 564. According to the present embodiment, by using a false color image, the burden on the user regarding the designation of the extracted color is reduced. In addition, since variation in color extraction is reduced, variation in image inspection results is also reduced.

  The image inspection apparatus 8 may further include a cluster number designation unit 518 that accepts designation of the number of clusters. The clustering unit 562 causes each pixel constituting the spectral image to belong to one of the number of clusters designated by the cluster number designation unit 518. Thereby, it becomes possible to reflect a user's intention about the number of clusters.

  As described with reference to FIG. 10 and the like, the extracted color designation unit 517 accepts designation of at least one of the foreground color that is the color of the foreground area and the background color that is the color of the background area in the false color image. You may have a background designation | designated part. The conversion unit 564 may convert the spectral image based on the foreground color into a foreground image that is one of the inspection images. The conversion unit 564 may convert the spectral image into a background image that is one of the inspection images based on the background color. The inspection unit 531 may be configured to determine pass / fail of the inspection object using the foreground image and the background image. Depending on the inspection tool, the image of the workpiece 2 may be divided into a foreground image and a background image, and a difference image between the foreground image and the background image may be obtained to perform image inspection. In this case, the extraction color designation unit 517 may accept designation of the foreground area and extract the foreground color from the foreground area, or may accept designation of the foreground color for the displayed image. The same applies to the background color. For example, as shown in FIG. 10, the foreground / background designation unit may individually accept foreground designation and background color designation. The foreground / background designation unit may set a representative color close to the foreground color in the color space among the representative colors of the plurality of clusters as the background color. In general, the background color is often a color separated from the foreground color, and the background color is often a color near the foreground color. That is, the representative color of the cluster located in the vicinity of the foreground cluster in the color space is often the background color. Therefore, the foreground / background designation unit may automatically determine the background color of the foreground color by obtaining and comparing the Euclidean distance between the clusters in the color space. As shown in FIG. 10, the foreground / background designation unit may accept designation of a plurality of foreground colors. For example, a plurality of shrimp colors included in the work 2 may be slightly different for each individual. In this case, by specifying a plurality of shrimp colors as a plurality of foreground colors, various shrimp individuals can be extracted by image inspection. Similarly, a plurality of background colors may be designated. As illustrated in FIG. 10, the foreground / background designation unit may accept designation of a plurality of background colors.

As shown in FIG. 11 and the like, the UI management unit 514 and the display unit 7 project the foreground color distribution and the background color distribution in the false color image into a two-dimensional or three-dimensional color space, thereby providing a foreground color. The degree of separation between the color and the background color may be displayed. Thereby, the user can confirm whether the foreground color and the background color are sufficiently separated. As illustrated in FIG. 13 and the like, the adjustment unit 519 may adjust the major axis and the minor axis of the ellipse surrounding the foreground color distribution in the two-dimensional color space according to a user operation. Thereby, the degree of separation between the foreground color and the background color can be increased. For example, the adjustment unit 519 adjusts the lightness scale and chromaticity scale in the variance-covariance matrix Σ, which is one of the color information of registered colors, according to the adjustment amount of the straight axis and the short axis. Variance-covariance matrix Σ can be decomposed into a matrix YY ^T and the chromaticity matrix ZZ ^T lightness. Furthermore, if a scale is introduced, it can be expressed as Σ = sy · YY ^T + sz · ZZ ^T. Therefore, by individually adjusting the coefficient sy that is the brightness scale and the coefficient sz that is the chromaticity scale, it is possible to individually adjust the brightness and chromaticity in the variance-covariance matrix Σ.

  The false color image generation unit 563 regenerates a gray image according to the adjustment amount of the long axis and the adjustment amount of the short axis of the ellipse adjusted by the adjustment unit 519. The adjustment unit 519 may display the regenerated (updated) gray image in the image display area 801. As a result, the user can determine the adjustment amount while checking the gray image.

  As described with reference to FIGS. 10 and 11, the radio buttons 1012, 1014, the pointer 706, and the like pay attention to the representative color of one of a plurality of clusters in the false color image displayed on the display unit 7. It is an example of the attention color designation | designated part designated as a color. For example, a radio button 1012, 1014, a pointer 706, or the like is an attention color designation unit that designates an attention color from a plurality of registered colors including the foreground color that is the color of the foreground area and the background color that is the color of the background area in the false color image. It is an example. As a result, the user can designate any registered color as the target color or comparison color. The adjustment unit 519 adjusts at least one of the major axis, the minor axis, and the center coordinates of the distribution surrounding the distribution of the target color projected on the two-dimensional or three-dimensional color space displayed on the display unit 7. To do. The display unit 7 may also display a color distribution of a comparative color to be compared with the target color along with the color distribution of the target color. The attention color designation unit may be configured to accept the designation of the background color as the comparison color when the foreground color is designated as the attention color. Further, the attention color designation unit may be configured to accept the designation of the foreground color as the comparison color when the background color is designated as the attention color. As described above, the comparison color may be automatically selected based on the target color.

  2 ... work, 3 ... lighting device, 4 ... camera, 5 ... image processing device, 510 ... processor, 511 ... MSI processing unit, 512 ... lighting control unit, 513 ... Imaging control unit, 531 ... Inspection unit

Claims (13)

An acquisition unit for acquiring a spectral image of the inspection object;
A display unit for displaying the spectral image acquired by the acquisition unit;
An area designating unit that accepts designation of an area including a plurality of pixels in the spectral image displayed on the display unit;
Clustering in which each pixel constituting the spectral image belongs to any one of a plurality of clusters according to positions in color space coordinates of a plurality of pixels included in each region specified by the region specifying unit. And
A false color image generating unit that determines a representative color for each of the plurality of clusters and generates a false color image by converting the color of each pixel constituting the spectral image into a representative color of the cluster to which each pixel belongs; ,
An extraction color designation unit that accepts designation of an extraction color to be extracted in the false color image displayed on the display unit;
A conversion unit that converts the spectral image into a gray image based on a distance in a color space between the color of each pixel of the spectral image and the extracted color;
An image inspection apparatus comprising: an inspection unit that performs an image inspection using the gray image generated by the conversion unit. A cluster number designating unit for accepting designation of the number of the plurality of clusters;
The image inspection apparatus according to claim 1, wherein the clustering unit causes each pixel constituting the spectral image to belong to one of the number of clusters designated by the cluster number designation unit. The extracted color designation unit includes a foreground / background designation unit that accepts designation of at least one of a foreground color that is a color of a foreground area and a background color that is a color of a background area in the false color image;
The conversion unit is configured to convert the spectral image to a foreground image based on the foreground color, and to convert the spectral image to a background image based on the background color,
The image inspection apparatus according to claim 1, wherein the inspection unit is configured to determine pass / fail of the inspection object using the foreground image and the background image.   The image inspection apparatus according to claim 3, wherein the foreground / background designation unit individually accepts designation of the foreground color and designation of the background color.   The image inspection apparatus according to claim 3, wherein the foreground / background designation unit sets a representative color close to the foreground in a color space among the representative colors of the plurality of clusters as the background color.   The image inspection apparatus according to claim 3, wherein the foreground / background designation unit accepts designation of a plurality of foreground colors.   The image inspection apparatus according to claim 3 or 4, wherein the foreground / background designation unit accepts designation of a plurality of background colors.   The display unit projects the foreground color distribution and the background color distribution in the false color image into a two-dimensional or three-dimensional color space, thereby separating the foreground color from the background color. The image inspection apparatus according to claim 3, wherein:   The image inspection apparatus according to claim 8, further comprising an adjustment unit that adjusts a major axis and a minor axis of an ellipse surrounding the foreground color distribution in the two-dimensional color space.   The image inspection according to claim 9, wherein the conversion unit regenerates the gray image according to an adjustment amount of a major axis and an adjustment amount of a minor axis of the ellipse adjusted by the adjustment unit. apparatus. An attention color designating unit that designates an attention color from a plurality of registered colors including a foreground color that is a color of a foreground area and a background color that is a color of a background area in the false color image;
The display unit displays a color distribution of a comparative color to be compared with the target color together with a color distribution of the target color projected in a two-dimensional or three-dimensional color space. Image inspection equipment.   The image inspection according to claim 11, wherein the attention color designation unit is configured to accept designation of the background color as the comparison color when the foreground color is designated as the attention color. apparatus.   The image inspection according to claim 11, wherein the attention color designation unit is configured to accept designation of the foreground color as the comparison color when the background color is designated as the attention color. apparatus.