JP2006086451A - Substrate-inspection device, and method and device for setting parameter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique for automatically generating the parameters to be used for a substrate inspection device. <P>SOLUTION: A device for setting a parameter maps the color of each pixel in a soldering region at a good-quality picture where the mounting position of a component is normal as an objective point and the color of each pixel in the soldering region at a defective image where the mounting position of the component is not normal as an exception point respectively in a color space (color histogram). Then, the device obtains a color range, which divides the color space and in which a difference between the number of objective points included in it and the number of exceptional points (frequency total value) is maximized, and sets the obtained color range as a color condition (color parameter) to be used for substrate inspection. Thus, the color condition, being one of parameters for the inspection is, generated automatically. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a technique for automatically generating parameters used in a substrate inspection apparatus.

  Conventionally, there has been proposed a board inspection apparatus for inspecting the mounting quality of a printed circuit board on which a large number of electronic components are mounted. In this type of printed circuit board, “the shape of the solder pile when the electrode part of the electronic component and the land are soldered” is called a solder fillet. However, depending on the wetting of the electrode part of the electronic component, a solder fillet is formed. In some cases, the electronic component and the solder fillet are not in contact with each other. Therefore, in order to inspect the soldering quality, it is necessary to accurately grasp the shape of the solder fillet made of a free curve.

  However, in the conventional board inspection apparatus, since monochrome (single color) single illumination is used as a light source, it is difficult to perform image analysis of the three-dimensional shape of the solder fillet. Therefore, the quality of soldering cannot be determined, and the board inspection apparatus cannot be used practically.

  In order to solve such a problem, the present applicant has proposed a substrate inspection apparatus of the type shown in FIG. 28 (see Patent Document 1). This method is called the three-color light source color highlight method (or simply the color highlight method), and is a technology that obtains the three-dimensional shape of the solder fillet as a pseudo-color image by illuminating the inspection object with light sources of multiple colors. is there.

  It is said that the practical use of automatic inspection of printed circuit boards is practically after the advent of this color highlighting technology. In particular, at the present time when electronic components are miniaturized, it is difficult to visually determine the solder fillet shape, and it can be said that board inspection cannot be realized without a color highlight type substrate inspection apparatus.

  As shown in FIG. 28, the color highlight type substrate inspection apparatus images the light projection unit 105 that irradiates the inspection target 107 on the substrate 110 with the three primary color lights at different incident angles, and the reflected light from the inspection target 107. An imaging unit 106. The light projecting unit 105 includes three annular light sources 111, 112, and 113 that have different diameters and that simultaneously emit red light, green light, and blue light based on a control signal from the control processing unit. Yes. The light sources 111, 112, and 113 are arranged in directions corresponding to different elevation angles when viewed from the inspection target 107 while being centered on the position directly above the inspection target 107.

  When the inspection target (solder fillet) 107 is irradiated by the light projecting unit 105 having such a configuration, light of a color corresponding to the inclination of the surface of the inspection target 107 enters the imaging unit 106. Therefore, as shown in FIG. 29, when the soldering of the electronic component is good / when the component is missing / when the solder is insufficient, the color pattern of the captured image depends on the shape of the solder fillet. A clear difference appears. This facilitates image analysis of the three-dimensional shape of the solder fillet, and makes it possible to accurately determine the presence / absence of electronic components and the quality of soldering.

In the color highlight type substrate inspection system, color parameters (color conditions) representing “the color of a good product that should be” and “the color of a defective product that should be” are set in advance, and the corresponding color parameter is selected from the inspection image. The color area to be extracted is extracted, and the quality is determined based on various feature amounts (for example, area and length) of the extracted area. Therefore, prior to the actual inspection, it is necessary to set the color parameters used for the inspection, the types of feature amounts, the determination conditions (for example, threshold values) for separating good products from defective products, and the like. The color parameters, feature amounts, and determination conditions are collectively referred to as inspection logic or inspection parameters, and setting and adjusting the inspection logic is generally referred to as teaching.

  In order to improve the inspection accuracy, it is important to set the color parameter so that a significant and clear difference appears between the feature quantity indicated by the non-defective product and the feature quantity indicated by the defective product. That is, it can be said that the quality of teaching of color parameters directly affects the inspection accuracy.

Therefore, as shown in FIG. 30, the present applicant has proposed a tool for supporting the setting of color parameters in the color highlight method (see Patent Document 2). In this tool, it is possible to set the upper limit value and the lower limit value of each of the hue ratios ROP, GOP, BOP and lightness data BRT of red, green, and blue as color parameters. The input screen of FIG. 30 is provided with a color parameter setting unit 127 for inputting color parameter setting values, and a setting range display unit 128 for displaying the color range extracted by each set color parameter. ing. The setting range display section 128 displays a hue diagram 134 showing all colors obtained under a predetermined brightness. When the operator sets the upper limit value and lower limit value of each color parameter, Displays a confirmation area 135 surrounding the color extracted by the set color parameter. When the binarization display button 129 is pressed, the extraction result based on the current color parameter is displayed as a binary image. According to this tool, the operator can track the color parameters until an appropriate extraction result is obtained while viewing the confirmation area 135 and the binary image.
Japanese Patent Laid-Open No. 2-78937 JP 9-145633 A

  The board inspection apparatus has an advantage that a plurality of inspection items can be inspected at high speed and accurately at once for the mounting quality of the printed board. However, in actual operation of the board inspection device, the over logic that teaches each inspection logic according to the individual inspection object, does not miss the defective product, and determines that the non-defective product is a defective product is an allowable value ( Judgment accuracy must be sufficiently increased until the value can be kept below the value assumed in advance.

  Complementing the oversight and overdetection of defective products, the outflow of defective products is never allowed in any inspection. If it is difficult to judge defective products and non-defective products, it is better to judge non-defective products as defective products. However, excessive detection increases the loss cost of discarding non-defective products as defective products or requires re-inspection of defective products. The merit of automating the inspection is lost.

  However, in the color highlight type substrate inspection apparatus, although advanced substrate inspection that can withstand practical use is possible, teaching to suppress oversight and overdetection of defective products to a target value is difficult. Even if the color parameter setting support tool described above is used, it is inevitable that the setting of a color parameter will depend on the experience and intuition of the operator. In addition, no matter how good the operator is, the adjustment must be repeated on a trial and error basis, which is inefficient and requires a lot of labor and adjustment time.

  Recently, the use of lead-free solder (lead-free solder) has been increasing due to consideration of environmental issues, but lead-free solder has the property of diffusing and reflecting light, so it can be used as a conventional lead solder (substantially mirror-reflected). There is also a problem that the color pattern becomes unclear.

  In a manufacturing environment where the product life cycle is shortening and the manufacturing environment is changing rapidly, it is strongly desired to reduce teaching work and to further automate teaching.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a technique capable of automatically generating parameters used in a substrate inspection apparatus.

  More specifically, an object of the present invention is to provide a technique capable of automatically generating parameters used for part missing inspection.

  In the present invention, an information processing device (parameter setting device) is obtained by first imaging a plurality of target images obtained by imaging a component to be detected by inspection and a component to be excluded by inspection. Acquire multiple excluded images. For example, in the case of a non-defective product inspection for detecting a non-defective product, an image of a component with a good mounting state is a target image, and an image of a component with a poor mounting state is an excluded image. Conversely, in the case of a defect inspection for detecting a defect, an image of a part having the defect is a target image, and other images are excluded images.

  In the first aspect of the present invention, the information processing apparatus acquires, as the target image, a solder area in a non-defective product image in which a component mounting position is normal, and a solder area in a defective product image in which the component mounting position is not normal. Get as. The information processing apparatus maps the color of each pixel of the target image as a target point, maps the color of each pixel of the excluded image as an excluded point, and maps the color space, and divides the color space. Then, a color range that maximizes the difference between the number of target points and the number of exclusion points included therein is obtained, and the obtained color range is set as a color condition (color parameter) used in substrate inspection.

  Thereby, a color condition which is one of inspection parameters is automatically generated. In the first aspect, the solder in the non-defective product image in which the component mounting position is normal and the solder in the defective product image in which the component mounting position is not normal (that is, the component is misaligned or missing) are color patterns. This is based on the fact that there is a clear difference.

  The color space used in the present invention may be a multidimensional color space including at least three axes of brightness, hue, and saturation. For example, the color space tends to be included in the target image and hardly included in the excluded image. It is also preferable to use a two-dimensional color space consisting of a saturation axis and a lightness axis for a certain hue. Employing the two-dimensional color space simplifies the color range search process. In the two-dimensional color space, if the color condition is composed of a lower limit and an upper limit of saturation and a lower limit and an upper limit of lightness, the color range becomes a rectangular area, and the color range search process is further simplified.

  In the second aspect of the present invention, the information processing apparatus maps the color of each pixel of the target image as a target point and the color of each pixel of the excluded image as a excluded point in the color space. Then, the information processing apparatus sets a color range that divides the color space, extracts a pixel area that satisfies the color range from each of the target image and the excluded image, and extracts a feature amount of the pixel area. A color range in which the degree of separation is maximized by creating a feature amount histogram and repeating a color range search process for calculating the degree of separation between the frequency distribution of the target image and the frequency distribution of the excluded image in the feature amount histogram. Ask for. Then, the obtained color range is set as a color condition used in the substrate inspection.

  Also with this configuration, a color condition, which is one of inspection parameters, is automatically generated. The second aspect utilizes the fact that the color range in which the degree of separation of the feature amount histogram is maximized is the optimal solution for the color condition to be obtained.

  In the color range search process, it is preferable to obtain a color range that maximizes the degree of separation by fixing the saturation range and changing only the brightness range. This simplifies the color range search process.

  In the third aspect of the present invention, the information processing apparatus acquires, as the target image, a component mounting area in a non-defective product image in which a component mounting position is normal, and the component mounting area in a defective product image in which the component mounting position is not normal. Acquired as an excluded image. Then, the information processing apparatus maps the color of each pixel of the target image as a target point and the color of each pixel of the exclusion image as an exclusion point to a color space, and divides the color space. Thus, a color range that maximizes the difference between the number of target points and the number of exclusion points included therein is obtained, and the obtained color range is set as a color condition used in substrate inspection.

  Also with this configuration, a color condition, which is one of inspection parameters, is automatically generated. The component mounting area refers to an area where the part should be placed. For example, in the case of a part to be soldered at both ends, the middle part of the solder area (or land area where the solder is placed) at both ends corresponds. To do. In other words, in the non-defective product image where the component mounting position is normal, the component body is shown in the component mounting area, whereas in the defective product image where the component mounting position is not normal, it is The board is reflected. The third aspect utilizes the fact that there is a clear difference between the color patterns of the component main body and the board.

  The method of using the difference in the color pattern of the component mounting area can perform component missing inspection with high accuracy even when solder having the property of diffusing and reflecting light, such as lead-free solder, is used. Therefore, it is also preferable to switch processing depending on the type of solder used for the substrate.

  That is, in the fourth aspect of the present invention, when the information processing apparatus uses solder having the property of diffusing and reflecting light, the component mounting area in the non-defective image in which the component mounting position is normal is the target image. And acquiring a component mounting region in a defective product image where the mounting position of the component is not normal as the exclusion image, otherwise acquiring the solder region in the good product image as the target image, and The solder area in the defective product image is acquired as the exclusion image.

  In the third aspect and the fourth aspect described above, the information processing apparatus captures the board area around the component in the non-defective image and the bare board before component mounting in addition to the component mounting area in the defective product image. It is also preferable to acquire the substrate area in the above as the exclusion area.

  In the non-defective image, the board area around the component and the board area of the bare board have a high probability that the board surface is clearly exposed. Therefore, by using these in the excluded image, the “board color” can be grasped more accurately. Therefore, the color of the target image (the color of the component main body) and the color of the excluded image (the color of the board) can be accurately determined, and the reliability of the color condition is improved.

  After the color condition is set as described above, the information processing apparatus extracts a pixel area that satisfies the color condition from each of the target image and the excluded image, and calculates a feature amount of the pixel area. Creating a feature amount histogram, calculating a threshold value for separating the feature amount of the target image and the feature amount of the excluded image based on the frequency distribution of the feature amount histogram, and calculating the calculated threshold value May be set as a determination condition used in substrate inspection. Thereby, a determination condition (threshold value), which is one of inspection parameters, is also automatically generated.

  Here, various features such as the area, area ratio, length, maximum width, center of gravity, and shape of the pixel region are assumed as the feature amount. What is necessary is just to employ | adopt one or two or more preferable feature-values according to the object which should be detected by test | inspection.

Each of the above processes is executed by a program of the information processing apparatus. The automatically generated parameters (color conditions and determination conditions) are stored in the storage unit of the substrate inspection apparatus and used for substrate inspection processing.

  The board inspection apparatus irradiates a mounting component on the board with light of a plurality of colors at different incident angles, and extracts an area that satisfies the color condition from an image obtained by imaging the reflected light. The mounting state of the component is inspected based on whether or not the feature quantity of the region satisfies the determination condition.

  Note that the present invention can be understood as a parameter setting method for a substrate inspection apparatus including at least a part of the above processing, or a program for realizing the method. The present invention can also be understood as a parameter setting device of a substrate inspection apparatus having at least a part of the means for executing the above processing, or a substrate inspection apparatus equipped with such a device. Each of the above means and processes can be combined with each other as much as possible to constitute the present invention.

  According to the present invention, it is possible to automatically generate parameters used in the board inspection apparatus, in particular, parameters used for component missing inspection, and it is possible to reduce teaching work and further to automate teaching.

  Exemplary embodiments of the present invention will be described in detail below with reference to the drawings.

<First Embodiment>
(Configuration of board inspection system)
FIG. 1 shows a hardware configuration of a board inspection system according to an embodiment of the present invention.

  The substrate inspection system includes a substrate inspection device 1 that executes substrate inspection processing and a parameter setting device 2 that automatically generates parameters used in the substrate inspection processing of the substrate inspection device 1. The board inspection apparatus 1 and the parameter setting apparatus 2 can exchange electronic data such as images and parameters via a wired or wireless network, or a recording medium such as an MO or a DVD. In the present embodiment, the board inspection apparatus 1 and the parameter setting apparatus 2 are configured separately, but it is also possible to integrate the function of the parameter setting apparatus into the board inspection apparatus main body.

(Configuration of board inspection equipment)
The board inspection apparatus 1 is an apparatus for automatically inspecting the mounting quality (soldering state, etc.) of the mounting component 21 on the board 20 by a color highlight method. The substrate inspection apparatus 1 generally includes an X stage 22, a Y stage 23, a light projecting unit 24, an imaging unit 25, and a control processing unit 26.

  Each of the X stage 22 and the Y stage 23 includes a motor (not shown) that operates based on a control signal from the control processing unit 26. By driving these motors, the X stage 22 moves the light projecting unit 24 and the imaging unit 25 in the X axis direction, and the Y stage 23 moves the conveyor 27 that supports the substrate 20 in the Y axis direction.

  The light projecting unit 24 includes three annular light sources 28, 29, and 30 that have different diameters and that simultaneously emit red light, green light, and blue light based on a control signal from the control processing unit 26. . The light sources 28, 29, and 30 are arranged in directions corresponding to different elevation angles when centered on the position directly above the observation position and viewed from the observation position. With this arrangement, the light projecting unit 24 irradiates the mounting component 21 on the substrate 20 with light of a plurality of colors (in this embodiment, three colors of R, G, and B) at different incident angles.

  The imaging unit 25 is a color camera, and is positioned downward at a position directly above the observation position. As a result, the reflected light on the substrate surface is imaged by the imaging unit 25, converted into color signals R, G, and B of the three primary colors and supplied to the control processing unit 26.

  The control processing unit 26 includes an A / D conversion unit 33, an image processing unit 34, an inspection logic storage unit 35, a determination unit 36, an imaging controller 31, an XY stage controller 37, a memory 38, a control unit (CPU) 39, and a storage unit 32. , An input unit 40, a display unit 41, a printer 42, a communication I / F 43, and the like.

  The A / D conversion unit 33 is a circuit that receives the color signals R, G, and B from the imaging unit 25 and converts them into digital signals. The digital grayscale image data for each hue is transferred to the image data storage area in the memory 38.

  The imaging controller 31 is a circuit including an interface for connecting the control unit 39 to the light projecting unit 24 and the image capturing unit 25, and the light amount of each light source 28, 29, 30 of the light projecting unit 24 based on the output of the control unit 39. And control such as maintaining the mutual balance of the hue light outputs of the imaging unit 25 is performed.

  The XY stage controller 37 is a circuit including an interface for connecting the control unit 39 to the X stage 22 and the Y stage 23, and controls driving of the X stage 22 and the Y stage 23 based on the output of the control unit 39.

  The inspection logic storage unit 35 is a storage unit that stores inspection logic used for substrate inspection processing. The board inspection apparatus 1 can perform a plurality of types of inspection processes such as a fillet inspection for inspecting a solder shape and a lack inspection for inspecting a missing part. The inspection logic is prepared for each type of inspection, and includes color parameters (color conditions) for extracting a predetermined color pattern (pixel area) from the image, types of feature values extracted from the color pattern, Consists of pass / fail judgment conditions related to the feature amount.

  The image processing unit 34 performs a process of extracting a region satisfying the color parameter from an image obtained by imaging the component 21 on the substrate 20 and a process of calculating a predetermined feature amount from the extracted region. It is. The determination unit 36 is a circuit that receives the feature amount calculated by the image processing unit 34 and executes processing for determining whether the component mounting state is good or not based on whether or not the feature amount satisfies a predetermined determination condition.

  The input unit 40 includes a keyboard, a mouse, and the like necessary for inputting operation information and data related to the substrate 20. The input data is supplied to the control unit 39. The communication I / F 43 is for transmitting and receiving data to and from the parameter setting device 2 and other external devices.

  The control unit (CPU) 39 is a circuit that executes various arithmetic processes and control processes. The storage unit 32 is a storage device composed of a hard disk and a memory, and stores the CAD information of the substrate, the determination result of the substrate inspection process, and the like in addition to the program executed by the control unit 39.

FIG. 2 shows a functional configuration of the substrate inspection apparatus 1. The board inspection apparatus 1 includes an instruction information reception function 10, a board carry-in function 11, a CAD information reading function 12, a stage operation function 13, an imaging function 14, an inspection logic reading function 15, an inspection function 16, a determination result writing function 17, and a board. An unloading function 18 is provided. These functions are realized by the control unit 39 controlling the hardware according to a program stored in the storage unit 32. In addition, in the storage unit 32, a CAD information storage unit 32a that stores CAD information and a determination result storage unit 3 that stores determination results.
2b is provided.

(Board inspection processing)
Next, substrate inspection processing in the substrate inspection apparatus 1 will be described. Here, component missing inspection will be described as an example of board inspection processing. The component missing inspection is a process for determining whether or not the mounting position of the component is normal, and is performed in order to find missing defects such as component misalignment and missing.

  As shown in the upper part of FIG. 3, when the component is mounted at a normal position (design position), the solder fillet shape has a wide inclined surface like a mountain skirt from the component 21 to the land on the substrate 20. It becomes. On the other hand, in the defective defective product, the solder spreads over the entire land, and the solder fillet shape at the center of the land becomes flat.

  When these solder fillets are imaged by the substrate inspection apparatus 1, images as shown in the middle of FIG. 3 are obtained. Since the red, green, and blue irradiation lights are incident on the solder fillet at different angles, the hue of the reflected light that is incident on the imaging unit 25 changes according to the inclination of the solder fillet. That is, the reflected light of the blue light having the shallowest incident angle is dominant in the steep portion, whereas the reflected light of the red light is dominant in the portion having almost no inclination. Therefore, a blue hue region is large in a non-defective solder fillet, and a red hue region is large in a defective solder fillet.

  In the missing inspection according to the present embodiment, such a tendency of the color pattern is used to determine whether or not the component is mounted based on the size (area) of the blue region. Hereinafter, the flow of the missing inspection process will be described in detail with reference to the flowchart of FIG.

  The instruction information receiving function 10 is in a waiting state until instruction information for instructing execution of substrate inspection is input (step S100; NO, step S101). When instruction information is input from an external device by operating the input unit 40 or via the communication I / F 43, the instruction information receiving function 10 receives the instruction information, the board carry-in function 11, the CAD information reading function 12, and the inspection logic. The data is sent to the reading function 15 (step S100; YES). The instruction information includes information (model number, etc.) of the board to be inspected.

  The inspection logic reading function 15 reads the inspection logic corresponding to the model number of the board from the inspection logic storage unit 35 (step S102). Here, inspection logic for missing inspection is read. The inspection logic includes a color parameter (color condition) and a threshold value (determination condition).

  The board carry-in function 11 carries the board 20 to be inspected from the printed board carry-in section onto the conveyor 27 based on the instruction information (step S103), and the CAD information reading function 12 loads the CAD corresponding to the board model number. Information is read from the CAD information storage unit 32a (step S104).

  Next, the stage operation function 13 obtains information such as the dimensions, shape, and component arrangement of the substrate 20 from the read CAD information, and the plurality of components 21 mounted on the substrate 20 are sequentially observed positions (imaging positions). The X stage 22 and the Y stage 23 are operated via the XY stage controller 37 (step S105).

On the other hand, the imaging function 14 causes the three light sources 28, 29, and 30 of the light projecting unit 24 to emit light via the imaging controller 31, and simultaneously irradiates red, green, and blue light onto the substrate 20. In addition, the imaging function 14 controls the imaging unit 25 via the imaging controller 31, and the stages 22 and 23.
The component 21 on the substrate 20 is imaged in synchronization with the above operation (step S106). The captured image is taken into the memory 38.

  Next, the inspection function 16 extracts a solder region from the captured image by the image processing unit 34 (step S107). The extraction of the solder region can be automatically performed by template matching, for example.

  Subsequently, the inspection function 16 binarizes the extracted solder region using the color parameter (step S108). The color parameters used here are composed of four values: a lower limit and an upper limit of blue saturation, and a lower limit and an upper limit of lightness. In the binarization process, pixels included in the color range defined by the color parameter are converted to white pixels, and other pixels are converted to black pixels.

  The lower part of FIG. 3 shows the solder area after binarization. By binarizing with the color parameter, it can be seen that only the blue color region in the solder region is extracted as a white pixel, and the difference (feature) between the non-defective image and the defective product image is clarified.

  Subsequently, the inspection function 16 uses the image processing unit 34 to extract the feature amount of the white pixel region. Here, the area (number of pixels) of the white pixel region is calculated as the feature amount. Then, the inspection function 16 passes the area value of the white pixel region to the determination unit 36, and the determination unit 36 compares the area value of the white pixel region with a threshold value (step S109). When the area value exceeds the threshold value (step S109; YES), it is determined that the mounting quality of the component 21 is good (step S110), and when the area value is equal to or less than the threshold value (step S109; NO), it is determined that the mounting quality of the component 21 is defective (step S111).

  The determination result writing function 17 writes the determination result together with the location ID (information for specifying a part) in the determination result storage unit 32b (step S112).

  When all the components on the board 20 have been inspected, the board carry-out function 18 carries out the board 20 by the printed board carrying section, and the board inspection process is finished (step S113).

  According to the board inspection process described above, it is possible to accurately grasp the three-dimensional shape of the solder fillet from the color pattern appearing in the two-dimensional image, and to accurately determine the presence or absence of a defect.

  By the way, in order to achieve high determination accuracy so that defective products are not overlooked and overdetection is less than an allowable value, the color parameters (color conditions) and threshold values (determination conditions) of the inspection logic are set in advance. It is necessary to set the optimum value according to the inspection object. In the present embodiment, the generation (teaching) of these parameters is automatically performed by the parameter setting device 2. This will be described in detail below.

(Configuration of parameter setting device)
As shown in FIG. 1, the parameter setting device 2 is a general-purpose device including a CPU, a memory, a hard disk, an I / O control unit, a communication I / F, a display unit, an information input unit (keyboard and mouse), etc. as basic hardware. It is composed of a computer (information processing device).

FIG. 5 shows a functional configuration of the parameter setting device 2. The parameter setting device 2 includes an instruction information reception function 50, a teacher image information reading function 51, an image acquisition function 52, a distribution function 53, a mapping function 54, a color range search function 55, a binarization function 56, and a feature amount histogram generation function. 57, a threshold value determination function 58, an inspection logic generation function 59, and an inspection logic writing function 60. These functions are realized by a program stored in a memory or a hard disk being read and executed by a CPU.

  In addition, a teacher image information DB 61 for storing teacher image information used for teaching is provided in the hard disk. The teacher image information includes an image of the mounted component imaged by the board inspection apparatus 1 and teacher information (teaching data) indicating whether the image should be detected (non-defective product) or excluded (defective product). In order to increase the reliability of teaching, it is preferable to prepare dozens to thousands of teacher image information for each of the non-defective product and the defective product.

(Parameter setting process)
The flow of parameter setting processing will be described with reference to the flowchart of FIG. In the present embodiment, an example in which inspection parameters used in the above-described missing inspection are generated will be described.

  The instruction information receiving function 50 is in a waiting state until instruction information for instructing automatic generation of inspection logic is input (step S200; NO, step S201). When the instruction information is input from the information input unit, the instruction information receiving function 50 transmits the instruction information to the teacher image information reading function 51 (step S200; YES). This instruction information includes information for specifying teacher image information to be subjected to inspection logic generation, the type of inspection logic, and the like.

  The teacher image information reading function 51 reads teacher image information corresponding to the examination logic to be created from the teacher image information DB 61 in accordance with the instruction information (step S202). The teacher image information includes a non-defective image (an image in which the component mounting position is normal) and a defective product image (an image in which the component mounting position is not normal). Teacher information is given to these images.

  FIG. 7 shows an example of a good product image and a defective product image. In the non-defective image, the component 62 is mounted at the designed position, and good solder fillets are formed in the land regions 63 and 63 at both ends of the component 62. The teacher information “good” is given to this image. On the other hand, in the defective product image, parts are missing, and flat solder fillets are formed in the land regions 65 and 65. The teacher information “bad” is given to this image.

  When the teacher image information is read, the image acquisition function 52 extracts a solder area from the image to which the teacher information is added (step S203). As shown in FIG. 8, the image acquisition function 52 has a template composed of a land window 70 and a component main body window 71, and enlarges / reduces the template, or relative to the land window 70 and the component main body window 71. The windows 70 and 71 are aligned with the land areas 63 and 65 and the part 62 in the image while shifting the position. If a part is missing as in the defective product image of FIG. 8, a part main body window 71 is temporarily placed in the middle of the land windows 70 at both ends. For example, a method such as template matching may be used for matching the windows. Thereby, the land areas 63 and 65 are specified for the non-defective product image and the defective product image, respectively. And the area | region except the overlap part with the component main body window 71 from the land window 70 is extracted as a solder area | region (refer the shaded part of FIG. 8). Note that the land area itself (the entire land window 70) may be handled as a solder area.

  Next, the distribution function 53 distributes the extracted solder area into the target image and the excluded image based on the teacher information (step S204). In this example, since the purpose is non-defective product detection, the solder area of the image to which the teacher information “good” is assigned is the target image, and the solder area of the image to which the teacher information “bad” is assigned is the excluded image.

The target image extracted here represents a good solder fillet when the component mounting position is normal, and the excluded image represents a bad solder fillet when a missing defect occurs. Therefore, creating an optimal color parameter for missing inspection involves finding an optimal solution in a color range that includes as many pixels as possible in the target image and that can eliminate almost all the colors of pixels in the excluded image. Is equivalent to

  Therefore, first, the mapping function 54 maps the colors of all pixels of the target image and the excluded image to the color histogram (step S205). At this time, the pixel of the target image is “target point”, and the pixel of the excluded image is “excluded point”, and the mapping is performed in a mutually distinguishable format. The color histogram is obtained by recording the frequency (number) of pixels at each point in the color space. The color histogram can grasp the color distribution of the pixels constituting the solder area. Note that the pixel referred to here is the minimum resolution of an image. When the mapping process is executed collectively for a plurality of pixels, color mixing occurs, and therefore the process for each pixel is preferable.

  In general, the color space is composed of a multidimensional space of at least hue, saturation, and brightness. Therefore, in order to accurately grasp the color distribution of the pixel, it is preferable to use a multidimensional color histogram in which the color of the pixel is mapped in the multidimensional color space.

  However, in the color highlight method, since red and blue are used for the light source, a red or blue color tends to appear strongly in the solder area (this causes reflection close to specular reflection on the solder surface). Because.) Further, as described above, it is also known that most pixels have a blue color in a good solder region, and most pixels have a red color in a defective solder region.

  Therefore, if the purpose is to determine the color parameters for separating the non-defective product color (target point) and the defective product color (exclusion point), one color (for example, blue) or two colors (for example, blue and red) are considered. This is enough. Therefore, in the present embodiment, blue is selected as a hue that is included in the target image and tends to be hardly included in the excluded image, and the pixel is placed in a two-dimensional color space including a blue saturation axis and a brightness axis. A two-dimensional color histogram in which colors are mapped is used. This greatly simplifies the algorithm for finding the optimal color parameter solution.

  FIG. 9 shows an example of a two-dimensional color histogram. The horizontal axis represents blue saturation. The larger the positive value, the stronger the blue component, and the larger the negative value, the stronger the yellow component, which is the complementary color of blue. The vertical axis represents the brightness, and the brightness increases as the value increases. White circles (◯) in the histogram represent target points, and black triangles (▲) represent exclusion points. It can be seen that there is a difference in color distribution between the target point and the excluded point.

  Next, the color range search function 55 searches for a color range that optimally divides the color distribution of the target point and the color distribution of the exclusion point based on the two-dimensional color histogram (step S206). In this embodiment, for simplification of the algorithm, as shown in FIG. 10A, the lower limit (BInf) and upper limit (BSup) of saturation, and the lower limit (LInf) and upper limit (LSup) of lightness are included. Consider a rectangular color range. The optimum solution to be obtained here is a color range that includes as many target points (◯) as possible and hardly includes exclusion points (（).

Specifically, the color range search function 55 calculates the frequency total value E for each color range while changing the values of BInf, BSup, LInf, and LSup (see Equation 1), and the frequency total value E is maximized. Find the color range. The frequency total value E is an index representing the difference between the number of target points (frequency) included in the color range and the number of excluded points (frequency). FIG. 10B shows a color range in which the frequency total value E is maximum.

  Then, the color range search function 55 sets a color range in which the frequency total value E is maximized as an inspection color parameter (color condition). As described above, according to the present embodiment, it is possible to automatically generate color parameters for appropriately separating the target image (target point) and the excluded image (excluded point).

  Next, processing for automatically generating an inspection threshold value (determination condition) is executed using the color parameter.

  First, the binarization function 56 binarizes all the solder areas of the non-defective product image and the defective product image using the color parameter (step S207). In this binarization processing, pixels included in the color range defined by the color parameter are converted to white pixels, and other pixels are converted to black pixels.

  As shown in FIG. 11, the white pixel region is very large in the non-defective image, and the white pixel region is extremely small in the defective image. Therefore, when such a binarized image is used, it becomes easy to quantitatively calculate a feature amount for identifying a non-defective product or a defective product. Examples of the feature amount include the area, area ratio, center of gravity, length, maximum width, and shape of the white pixel region. Here, the area is selected as the feature amount.

  The feature amount histogram generation function 57 grasps the difference between the distribution trend of the feature amount of the non-defective image and the distribution trend of the feature amount of the non-defective image, and thus the area value of the white pixel region for each of the non-defective image and the defective product image. An area histogram is created for step S208. FIG. 12 shows an example of an area histogram of a non-defective product image and a defective product image (hereinafter simply referred to as “good product histogram” or “defective product histogram”). It can be seen that a clear difference appears between the feature quantity distribution of the non-defective image and the feature quantity distribution of the defective product image.

  Next, the threshold value determination function 58 calculates a threshold value for optimally separating the feature quantity of the non-defective product image and the feature quantity of the defective product image based on the frequency distribution of the non-defective product histogram and the defective product histogram ( Step S209). Various methods for optimally separating the two peaks appearing in the feature amount histogram have been proposed, and any method may be adopted here. For example, Otsu's discriminant analysis method may be used, or a point separated by 3σ from the edge of a non-defective image peak may be determined as a threshold based on experience. In this way, a threshold value for discriminating between non-defective products and defective products is generated.

Then, the inspection logic generation function 59 generates inspection logic from the color parameter, the type of feature amount (area in this example), and the threshold value (step S210), and the inspection logic writing function 60 generates the inspection logic on the substrate. The data is written in the inspection logic storage unit 35 of the inspection device 1 (step S211).

  According to the present embodiment described above, since the inspection logic (parameter) used in the component missing inspection is automatically generated, the time and load required for teaching can be greatly reduced.

  In addition, since the optimum color parameter and threshold value are calculated by the above-described algorithm, it is possible to perform pass / fail judgment by the color highlight method with high accuracy. Note that the reliability of the color parameter and the threshold value is improved as the number of teacher image information to be given first increases.

Second Embodiment
In the missing inspection process of the first embodiment, the presence or absence of a missing defect is determined based on the area of the blue color pixel in the solder area (non-defective product inspection). Conversely, the red color pixel in the solder area It is also possible to determine the presence or absence of missing defects (inspection of defective products) by examining the area of each. This is because attention is paid to the fact that many reddish colors appear in the center of the land in the defective defective image, whereas red colors tend to hardly appear in the centered land of the non-defective image.

  The general flow of the inspection process is the same as that of the first embodiment (FIG. 4). However, (1) the color parameter (color condition) used is composed of four values, the lower limit and upper limit of the saturation of red, and the lower limit and upper limit of brightness, and (2) after binarization The difference is that when the area value of the white pixel region exceeds the threshold value, the mounting quality of the component is determined to be poor, and when the area value is equal to or less than the threshold value, the mounting quality is determined to be good.

  Such color parameters and threshold values can be automatically generated by setting a missing defective product image as a target image and a non-defective product image as an excluded image in the parameter setting process of the first embodiment. In the form, another method is adopted. This will be described in detail below.

  FIG. 13 shows a functional configuration of the parameter setting device 2. The parameter setting device 2 of the present embodiment has the same functional configuration as that of the first embodiment. However, the parameter setting device 2 newly includes a color range setting function 80 and a separation degree calculation function 81. The color range search function is configured by the conversion function 56, the feature amount histogram generation function 57, and the separation degree calculation function 81. These functions are also realized by a program stored in a memory or a hard disk being read and executed by the CPU.

  A flow of parameter setting processing in the second embodiment will be described along the flowchart of FIG. Note that the same steps as those in the first embodiment are denoted by the same step numbers.

  In the parameter setting device 2, the teacher image information is read and the solder region to which the teacher information is added is extracted according to the same process as in the first embodiment (steps S200 to S203). An image of a solder fillet with an inclined surface from a non-defective image (an image with a normal component mounting position), and an image of a flat solder fillet from a defective product image (an image with an incorrect component mounting position) Extracted.

  Next, the distribution function 53 distributes the extracted solder area into the target image and the excluded image based on the teacher information (step S204). In this example, since the purpose is to detect defective products, the solder area to which the teacher information “defective” is assigned is the target image, and the solder area to which the teacher information “good” is assigned is the excluded image. The solder area to which the teacher information “ignore” is given is ignored.

The mapping function 54 maps the colors of all pixels of the target image and the excluded image to the color histogram (step S205). At this time, the pixel of the target image is “target point”, and the pixel of the excluded image is “excluded point”, and the mapping is performed in a mutually distinguishable format.

  In the present embodiment, red is selected as a hue that is included in a large amount in the target image (defective product solder region) and hardly included in the excluded image (non-defective product solder region). A two-dimensional color histogram is used in which pixel colors are mapped in a two-dimensional color space consisting of lightness axes.

  FIG. 15 shows an example of a two-dimensional color histogram. The horizontal axis represents the saturation of red. The larger the positive value, the stronger the red component, and the larger the negative value, the stronger the cyan component that is the complementary color of red. The vertical axis represents the brightness, and the brightness increases as the value increases. White circles (◯) in the histogram represent target points, and black triangles (▲) represent exclusion points. It can be seen that there is a difference in color distribution between the target point and the excluded point.

  Subsequently, in the present embodiment, the color range search function sets a color range for dividing the color histogram, extracts a pixel region that satisfies the color range from each of the target image and the excluded image, and has the pixel region Separation by repeating a series of color range search processes, such as creating an area histogram for feature quantities (area values) and calculating the degree of separation between the frequency distribution of the target image and the frequency distribution of the excluded image in the area histogram Find the color range that maximizes the degree.

  Specifically, first, the color range setting function 80 sets an initial value of the color range (step S300). Here, as shown in FIG. 16A, the initial value of the color range is set so as to cover the entire range of red saturation and include the intermediate brightness to the maximum brightness. That is, the lower limit of saturation RInf = 0, the upper limit of saturation RSup = maximum saturation (170), the lower limit of brightness LInf = intermediate brightness, and the upper limit of brightness LSup = maximum brightness (255). The initial value of the intermediate brightness may be selected appropriately. For example, it may be set to a value of about 50% to 70% of the maximum brightness or set to the brightness of the target point having the maximum power.

  Next, the binarization function 56 binarizes all solder areas of the non-defective product image and the defective product image using the color range (step S301). In this binarization processing, pixels included in the color range are converted into white pixels, and other pixels are converted into black pixels. Since this color range includes a red color, the white pixel area is larger in the solder area of the defective image than in the non-defective image.

  Similar to the first embodiment, the feature amount histogram generation function 57 selects an area value as the feature amount of the white pixel region, and creates a non-defective product histogram and a defective product histogram related to the area value (step S302). As shown in FIG. 16A, the non-defective product histogram and the defective product histogram are overlapped with each other because the target point and the excluded point are not properly separated in the initial color range.

  Next, the separation degree calculation function 81 calculates the separation degree between the non-defective product histogram and the defective product histogram (step S303). Here, “distance (difference) between the upper limit value of the non-defective product histogram and the lower limit value of the defective product histogram” is defined as the degree of separation. A degree of separation other than this definition (for example, the peak-to-peak distance between a good product histogram and a defective product histogram) may be employed. The calculated separation degree is stored in the memory together with each value of the color range.

Thereafter, the color range is sequentially updated by the color range setting function 80 (step S305), and the degree of separation in each color range is calculated and stored in the memory (steps S301 to S304; NO). At this time, the color range setting function 80 changes only the lightness range by fixing the saturation range and reducing only the lightness lower limit LInf by a predetermined amount. Then, as shown in FIGS. 16A to 16C, the frequency distribution of the non-defective product histogram and the defective product histogram changes according to the color range. Usually, as the color range is widened, the separation degree between the non-defective product histogram and the defective product histogram is increased and becomes a maximum at a certain point, and when the color range is exceeded, the separation degree is decreased.

  When the lightness lower limit LInf of the color range reaches the minimum value (0 or the minimum lightness of the exclusion point), the color range search function ends the color range search process (step S304; YES). Then, the degree of separation in each color range stored in the memory is compared, and the color range having the maximum degree of separation is set as an inspection color parameter (color condition) (step S306).

  Subsequently, the threshold value determination function 58 optimally separates the feature quantity of the non-defective image and the feature quantity of the defective product image based on the frequency distribution of the non-defective product histogram and the defective product histogram in the area histogram having the maximum degree of separation. A threshold value for calculating the threshold is calculated (step S307).

  Thereafter, the inspection logic is generated and recorded in the same manner as in the first embodiment (steps S210 to S211), and the parameter setting process ends.

  Also according to the present embodiment described above, the inspection logic (parameter) used in the component missing inspection is automatically generated, so that the time and load required for teaching can be greatly reduced.

<Third Embodiment>
In recent years, the use of lead-free solder (lead-free solder) that does not contain lead has been increasing in consideration of environmental issues. However, since lead-free solder has a property that the surface becomes rough, there is a problem in that irradiation light is diffusely reflected on the surface of the solder, and color mixture of red, green, and blue light tends to occur (see FIG. 17).

  Therefore, in the image of the defective defective product, the red color in the center of the land is weakened and the hue of blue and green is increased. On the other hand, in the good product image, the blue color is weakened and the hue of red and green is increased. The difference in the color pattern of the defective product becomes extremely small. For example, when a color histogram is created for a component image using lead-free solder in the same procedure as in the second embodiment, the result is as shown in FIG. In the figure, the white circle (◯) represents the color of the pixel in the solder area of the defective defective product image, and the black triangle (▲) represents the color of the pixel in the solder area of the non-defective product image. As can be seen from this color histogram, it is difficult to clearly distinguish good products from defective products even if attention is paid to the color of the solder region. In the missing inspection processing in the first embodiment and the second embodiment, the pass / fail judgment is performed. It cannot be performed with high accuracy.

  Therefore, in the third embodiment of the present invention, in order to determine the missing defect of a component using lead-free solder, the color of the component mounting region (that is, the presence / absence of the component) is used instead of the color of the solder region. Pay attention. The component mounting area refers to an area where a component should be originally arranged. For example, as shown in FIG. 19, in the case of a component to which both ends are soldered, the central portion of the solder area (or land area on which the solder is placed) at both ends corresponds to the component mounting area. “Part color” appears in the component mounting area in the non-defective product image where the component mounting position is normal, whereas “Board” appears in the component mounting area in the defective product image where the component mounting position is not normal (misalignment or missing). Appears. " Since the color and material are different between the component surface and the substrate surface, a clear difference appears between the colors. In the present embodiment, the missing defect is determined based on the difference.

The general flow of the inspection process is the same as that of the first embodiment (FIG. 4). However, (1) it is not the solder area but the component mounting area that is extracted from the captured image as the inspection target area, and (2) the color parameter (color condition) used is the lower limit of the saturation of red. And the upper limit, and the difference between the lower limit and the upper limit of the brightness. Information (inspection area information) for specifying a location to be extracted as an inspection area is defined in the inspection logic. The reason why the red saturation is adopted as the color parameter is based on the knowledge that the component generally appears reddish and the substrate tends to appear blackish. When different tendencies appear depending on the material and color of the component or board, the content of the color parameter may be changed as appropriate.

  Now, a method for generating color parameters and threshold values used in the inspection process will be described. Since the functional configuration of the parameter setting device 2 is the same as that of the first embodiment (FIG. 5), description thereof is omitted.

  The flow of the parameter setting process will be described along the flowchart of FIG. Note that the same steps as those in the first embodiment are denoted by the same step numbers.

  In the parameter setting device 2, the teacher image information is read according to the same processing as in the first embodiment (steps S201 to S202).

  Next, the image acquisition function 52 extracts a component mounting area from the image to which teacher information is added (step S310). As shown in FIG. 21, the image acquisition function 52 has a template including a land window 70, a component main body window 71, and a mounting window 72. The template can be enlarged / reduced or the land window 70 and the component can be enlarged. While shifting the relative position of the main body window 71, the windows 70 and 71 are aligned with the land areas 63 and 65 and the part 62 in the image, as in the first embodiment. The mounting window 72 is arranged between the two land windows 70. An area surrounded by the mounting window 72 is extracted as a component mounting area.

  Next, the distribution function 53 distributes the extracted component mounting area into the target image and the excluded image based on the teacher information (step S311). In this example, because the purpose is non-defective product detection, the component mounting area of the image with the teacher information “good” is set as the target image, and the component mounting area of the image with the teacher information “bad” is set as the excluded image. The The target image is an image of the component main body, and the excluded image is an image of the board surface.

  Thereafter, according to the same process as in the first embodiment, a color histogram (consisting of a red saturation axis and a brightness axis) is created for the target image and the excluded image, a color parameter is determined by color range search, and the color A feature amount histogram is created based on the parameters, threshold values for discriminating between non-defective products and defective products are determined, and inspection logic is generated and recorded (steps S205 to S211).

  According to the present embodiment described above, since the inspection logic (parameter) used in the component missing inspection is automatically generated, the time and load required for teaching can be greatly reduced.

  In addition, since this embodiment uses the difference in the color pattern of the component mounting area, even when solder having the property of diffusing and reflecting light, such as lead-free solder, is used, it is possible to eliminate defective parts with high accuracy. Can be determined. Note that it is also preferable to apply the inspection processing of this embodiment to conventional lead solder.

<Fourth embodiment>
In the component mounting area of the defective product image, a part of the land, the solder, or a part of the displaced component may be reflected. In such a case, the parameter setting method of the third embodiment cannot accurately extract the color of the substrate, and the reliability of the color parameters and threshold values may be lowered. Therefore, in order to accurately grasp the color of the board, it is preferable to obtain the color of the board from other than the component mounting area of the defective product image. Therefore, in the fourth embodiment of the present invention, the color of the board is extracted from the board area around the component in the non-defective image.

  The flow of parameter setting processing in the fourth embodiment will be described along the flowchart of FIG. In addition, the same step number is attached | subjected about the same process as the said embodiment.

  In the parameter setting device 2, the teacher image information is read according to the same processing as in the first embodiment (steps S201 to S202).

  As shown in FIG. 23, the image acquisition function 52 has a template including a land window 70, a component main body window 71, a mounting window 72, and a peripheral window 73. The template can be enlarged / reduced, While shifting the relative positions of the window 70 and the component main body window 71, the windows 70 and 71 are aligned with the land regions 63 and 65 and the component 62 in the image, as in the first embodiment. The mounting window 72 is arranged between the two land windows 70, and the peripheral window 73 is arranged so as to surround the land window 70 and the component main body window 71.

  Then, the image acquisition function 52 extracts a component mounting area (area surrounded by the mounting window 72) and a board area (area excluding the component main body window 71 from the peripheral window 73) from the non-defective image. Further, only the component mounting area is extracted from the defective product image (step S320).

  Next, based on the teacher information, the distribution function 53 allocates the non-defective component mounting area to the target image and the defective component image mounting area and the non-defective image board area to the exclusion image (step S321). The subsequent processing is the same as in the above embodiment.

  In the non-defective image, there is a high probability that the substrate surface is clearly exposed in the substrate area around the component. Therefore, by using this as an excluded image, the “substrate color” can be grasped more accurately. Therefore, in the color range search process (steps S205 and S206), the color of the target image (the color of the component main body) and the color of the excluded image (the color of the board) can be accurately determined, and the reliability of the color parameters. Will improve.

<Fifth Embodiment>
In the fourth embodiment, in order to acquire the color of the board, the region around the component in the non-defective image is extracted. However, depending on the board, as shown in FIG. 24, a wiring pattern may be formed in the board area (shaded area) around the component, or a part of the solder may protrude. In such a case, since the wiring pattern and the solder color are extracted together with the substrate color as noise, the color parameter for separating the component color and the substrate color may not be set appropriately. FIG. 24 shows an example in which the color parameter is set wider due to the influence of noise.

  Therefore, in the fifth embodiment of the present invention, the color of the board is extracted from the component mounting area in the bare board image (image obtained by imaging the board before the component is mounted).

  The flow of parameter setting processing in the fifth embodiment will be described along the flowchart of FIG. In addition, the same step number is attached | subjected about the same process as the said embodiment.

  In the parameter setting device 2, the teacher image information is read according to the same processing as in the first embodiment (steps S201 to S202). This teacher image information includes a bare board image.

  As shown in FIG. 26, the image acquisition function 52 extracts a component mounting area from each of the non-defective product image, the defective product image, and the bare board image by template matching (step S330). Next, the distribution function 53 distributes the non-defective component mounting area to the target image and the defective product image and the bare board image component mounting area to the exclusion image based on the teacher information (step S331). The subsequent processing is the same as in the third embodiment.

  In the component mounting area of the bare board, the substrate surface is completely exposed, and elements such as wiring patterns and solder are not included. Therefore, according to the present embodiment, it is possible to extract a substrate area without noise by using the bare board image, and to grasp the color of the substrate more accurately. Therefore, the reliability of the color parameter can be further improved.

<Sixth Embodiment>
In the sixth embodiment of the present invention, a method for changing inspection logic to be generated according to the type of solder will be described.

  The parameter setting device 2 of the present embodiment includes a solder type determination function (not shown) that determines the type of solder and switches processing. The other functional configuration is the same as that of the first embodiment (FIG. 5).

  As shown in the flowchart of FIG. 27, when the instruction information is input from the information input unit, the instruction information reception function 50 transmits the instruction information to the solder type determination function (step S200; YES). This instruction information includes solder type information regarding the type of solder.

  Based on the solder type information, the solder type determining function determines whether or not the substrate to be processed uses lead-free solder (step S340). In the case of lead-free solder, the solder type determination function shifts the processing to step S202 in any of the third to fifth embodiments (step S340; YES). Conversely, if it is not lead-free solder, the process proceeds to step S202 in the first or second embodiment (step S340; NO).

  When the color parameter and the threshold value are calculated, the inspection logic generation function 59 generates the inspection logic from the color parameter, the feature amount type, the threshold value, and the inspection target area information. The inspection target area is set in the component mounting area in the case of lead-free solder, and is set in the solder area in other cases.

  According to the processing of this embodiment, appropriate inspection logic is generated according to the type of solder. Therefore, in the case of lead solder and lead-free solder, it is possible to inspect the missing parts with high accuracy.

<Modification>
The first to sixth embodiments described above are merely examples of the present invention. The scope of the present invention is not limited to the above embodiment, and various modifications can be made within the scope of the technical idea.

  For example, in the above embodiment, a two-dimensional color histogram (color space) is used, but a multi-dimensional (hue, saturation, brightness) color histogram may be used. Also for the two-dimensional color histogram, the saturation axis of other hues such as red, green, and yellow may be used instead of the blue saturation axis, or the hue axis may be used instead of the saturation axis. The selection of the axis of the color histogram may be determined according to the tendency of the color pattern of the component image captured by the board inspection apparatus.

  Further, the color range is not limited to a rectangle, and a circle, a polygon, a free curve figure, or the like may be used. Furthermore, when the color histogram is multidimensional, the color range may be multidimensional.

  In the above embodiment, the missing inspection has been described as an example. However, the present invention performs region extraction based on color parameters (color conditions), and determines some feature amount of the extracted region based on the determination condition. If so, the present invention can be applied to other substrate inspection processes.

  In the above embodiment, the area is used as the feature amount. However, as the feature amount used for the pass / fail judgment, an area ratio, a length, a maximum width, a center of gravity, and the like can be preferably used. The area ratio is the occupation ratio of the binarized area in the land window. For example, if a component is soldered with a deviation from the land area, the area of the solder area increases and the area ratio changes. If this is regarded as a feature amount, it is effective for inspection of component displacement. The length is the length in the vertical direction or the horizontal direction of the white pixel region, and the maximum length is the maximum value among the lengths of the white pixel region. The center of gravity is a relative position of the center of gravity of the white pixel region with respect to the land window.

  Any feature amount may be used as long as it can accurately determine pass / fail, and it is also preferable to combine a plurality of types of feature amounts to improve accuracy. It is also possible to extract a plurality of types of feature amounts in the parameter setting process, and to adopt a feature amount that best separates non-defective products and defective products among them. In the above embodiment, an area histogram (area value histogram) is used to determine the determination condition (threshold value). However, if the type of feature amount is different, a feature amount histogram (area ratio histogram, length histogram, Maximum width histogram, centroid histogram, etc.). For example, if an area ratio histogram is used instead of the area value histogram, the pass / fail judgment is executed based on the pixel occupation rate binarized by the color parameter in the land window. Even when the size becomes smaller or larger, a determination process that is not affected by the size of the land window is possible.

  It is also preferable to combine the processes of the first to sixth embodiments as appropriate. For example, by combining the inspection process of the first embodiment (a process for detecting a non-defective product) and the inspection process of the second embodiment (a process for detecting a defective product), the determination accuracy is further improved. A highly reliable missing inspection with almost no over-detection can be performed. It is also preferable to combine the fourth embodiment and the fifth embodiment and extract the non-defective image substrate region and the bare board image substrate region as the excluded images. Further, a method of searching for a color range based on the degree of separation of the feature amount histogram as in the second embodiment may be applied to the third to sixth embodiments.

The figure which shows the hardware constitutions of the board | substrate inspection system which concerns on embodiment of this invention. The figure which shows the function structure of a board | substrate inspection apparatus. The figure which shows the relationship between the shape of a solder fillet, an imaging pattern, and a binarized image. The flowchart which shows the flow of a board | substrate inspection process. The figure which shows the function structure of the parameter setting apparatus which concerns on 1st Embodiment. The flowchart which shows the flow of the parameter setting process which concerns on 1st Embodiment. The figure which shows an example of a quality product image and a defective product image. The figure which shows the extraction process of a solder area | region. The figure which shows an example of a two-dimensional color histogram. The figure which shows the search process of a color range. The figure which shows an example of the binarization result of a non-defective product image and a defective product image. The figure which shows the area histogram and threshold value determination process of a good article and inferior goods. The figure which shows the function structure of the parameter setting apparatus which concerns on 2nd Embodiment. The flowchart which shows the flow of the parameter setting process which concerns on 2nd Embodiment. The figure which shows an example of the two-dimensional color histogram in 2nd Embodiment. The figure which shows the flow of a color range search process. The figure which shows the mode of the diffuse reflection which arises with lead-free solder. The figure which shows an example of the two-dimensional color histogram regarding the component image using lead-free solder. The figure which shows an example of a component mounting area | region. The flowchart which shows the flow of the parameter setting process which concerns on 3rd Embodiment. The figure which shows the extraction process of the components mounting area | region in 3rd Embodiment. The flowchart which shows the flow of the parameter setting process which concerns on 4th Embodiment. The figure which shows the extraction process of the component mounting area | region and board | substrate area | region in 4th Embodiment. The figure which shows the problem when noise is contained in a board | substrate area | region. The flowchart which shows the flow of the parameter setting process which concerns on 5th Embodiment. The figure which shows the extraction process of the component mounting area | region and board | substrate area | region in 5th Embodiment. 10 is a flowchart showing a flow of parameter setting processing according to a sixth embodiment. The figure which shows the structure of the board | substrate inspection apparatus of a color highlight system. The figure which shows an example of the color pattern which appears in a captured image. The figure which shows the setting support tool of a color parameter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Board | substrate inspection apparatus 2 Parameter setting apparatus 10 Instruction information reception function 11 Board | substrate carrying-in function 12 CAD information reading function 13 Stage operation function 14 Imaging function 15 Inspection logic reading function 16 Inspection function 17 Judgment result writing function 18 Board | substrate unloading function 20 Board | substrate 21 Mounted parts 22 X stage 23 Y stage 24 Projection unit 25 Imaging unit 26 Control processing unit 27 Conveyor 28 Red light source 29 Green light source 30 Blue light source 31 Imaging controller 32 Storage unit 32a CAD information storage unit 32b Judgment result storage unit 33 A / D Conversion unit 34 Image processing unit 35 Inspection logic storage unit 36 Determination unit 37 XY stage controller 38 Memory 39 Control unit 40 Input unit 41 Display unit 42 Printer 50 Instruction information reception function 51 Teacher image information reading function 52 Image acquisition function 53 Distribution function 4 Mapping Function 55 Color Range Search Function 56 Binarization Function 57 Feature Quantity Histogram Generation Function 58 Threshold Determination Function 59 Inspection Logic Generation Function 60 Inspection Logic Write Function 62 Parts 63, 65 Land Area 70 Land Window 71 Parts Body Window 72 Mounting window 73 Peripheral window 80 Color range setting function 81 Separation degree calculation function

Claims (17)

A region satisfying a predetermined color condition is extracted from an image obtained by irradiating a component mounted on the board with light of multiple colors at different angles of incidence and imaging the reflected light, and the features of the extracted region Is a method of automatically generating parameters used in a board inspection apparatus that inspects the mounting state of the component depending on whether or not a predetermined determination condition is satisfied,
Information processing device
Obtaining a plurality of target images obtained by imaging the parts to be detected by the inspection and a plurality of exclusion images obtained by imaging the parts to be excluded by the inspection;
Mapping the color of each pixel of the target image as a target point and the color of each pixel of the excluded image as an exclusion point, respectively, and mapping them to a color space,
A color range that divides the color space, and obtaining a color range that maximizes the difference between the number of target points included therein and the number of excluded points;
In the parameter setting method of the substrate inspection apparatus for setting the obtained color range as a color condition used in the substrate inspection,
The information processing apparatus acquires a solder region in a non-defective image with a normal component mounting position as the target image, and acquires a solder region in a defective product image with a non-normal component mounting position as the exclusion image. Parameter setting method. A region satisfying a predetermined color condition is extracted from an image obtained by irradiating a component mounted on the board with light of multiple colors at different angles of incidence and imaging the reflected light, and the features of the extracted region Is a method of automatically generating parameters used in a board inspection apparatus that inspects the mounting state of the component depending on whether or not a predetermined determination condition is satisfied,
Information processing device
Obtaining a plurality of target images obtained by imaging the parts to be detected by the inspection and a plurality of exclusion images obtained by imaging the parts to be excluded by the inspection;
Mapping the color of each pixel of the target image as a target point and the color of each pixel of the excluded image as an exclusion point, respectively, and mapping them to a color space,
Set a color range that divides the color space, extract a pixel region that satisfies the color range from each of the target image and the excluded image, and create a feature amount histogram for the feature amount of the pixel region, By repeating the color range search process for calculating the degree of separation between the frequency distribution of the target image and the frequency distribution of the excluded image in the feature amount histogram, a color range that maximizes the degree of separation is obtained,
A parameter setting method for a substrate inspection apparatus, wherein the obtained color range is set as a color condition used in substrate inspection. The color space is a multidimensional color space consisting of at least a saturation axis and a lightness axis for hues that are included in the target image and tend to be hardly included in the excluded image,
3. The parameter setting method for a substrate inspection apparatus according to claim 2, wherein in the color range search process, a saturation range is fixed and only a brightness range is changed to obtain a color range in which the degree of separation is maximized. A region satisfying a predetermined color condition is extracted from an image obtained by irradiating a component mounted on the board with light of multiple colors at different angles of incidence and imaging the reflected light, and the features of the extracted region Is a method of automatically generating parameters used in a board inspection apparatus that inspects the mounting state of the component depending on whether or not a predetermined determination condition is satisfied,
Information processing device
Obtaining a plurality of target images obtained by imaging the parts to be detected by the inspection and a plurality of exclusion images obtained by imaging the parts to be excluded by the inspection;
Mapping the color of each pixel of the target image as a target point and the color of each pixel of the excluded image as an exclusion point, respectively, and mapping them to a color space,
A color range that divides the color space, and obtaining a color range that maximizes the difference between the number of target points included therein and the number of excluded points;
In the parameter setting method of the substrate inspection apparatus for setting the obtained color range as a color condition used in the substrate inspection,
The information processing apparatus acquires a component mounting area in a non-defective image with a normal component mounting position as the target image, and acquires a component mounting area in a defective product image with a non-normal component mounting position as the exclusion image. Device parameter setting method. A region satisfying a predetermined color condition is extracted from an image obtained by irradiating a component mounted on the board with light of multiple colors at different angles of incidence and imaging the reflected light, and the features of the extracted region Is a method of automatically generating parameters used in a board inspection apparatus that inspects the mounting state of the component depending on whether or not a predetermined determination condition is satisfied,
Information processing device
Obtaining a plurality of target images obtained by imaging the parts to be detected by the inspection and a plurality of exclusion images obtained by imaging the parts to be excluded by the inspection;
Mapping the color of each pixel of the target image as a target point and the color of each pixel of the excluded image as an exclusion point, respectively, and mapping them to a color space,
A color range that divides the color space, and obtaining a color range that maximizes the difference between the number of target points included therein and the number of excluded points;
In the parameter setting method of the substrate inspection apparatus for setting the obtained color range as a color condition used in the substrate inspection,
The information processing apparatus includes:
When solder having the property of diffusing and reflecting light is used, a component mounting area in a non-defective product image in which the component mounting position is normal is acquired as the target image, and a defective product image in which the component mounting position is not normal The component mounting area at is acquired as the exclusion image,
In other cases, the parameter setting method of the board inspection apparatus that acquires the solder area in the non-defective image as the target image and acquires the solder area in the defective image as the exclusion image. 6. The parameter setting method for a board inspection apparatus according to claim 4, wherein the information processing apparatus acquires a board area around a part in the non-defective image in addition to a part mounting area in the defective product image as the exclusion image. 6. The board inspection according to claim 4, wherein the information processing apparatus acquires, as the exclusion area, a board area in a bare board image obtained by imaging a bare board before component mounting in addition to a part mounting area in the defective product image. Device parameter setting method. The information processing apparatus is
Extracting a pixel region that satisfies the color condition from each of the target image and the excluded image, and creating a feature amount histogram for the feature amount of the pixel region,
Calculating a threshold for separating the feature amount of the target image and the feature amount of the excluded image based on the frequency distribution of the feature amount histogram;
The parameter setting method for a substrate inspection apparatus according to claim 1, wherein the calculated threshold value is set as a determination condition used in substrate inspection. A region satisfying a predetermined color condition is extracted from an image obtained by irradiating a component mounted on the board with light of multiple colors at different angles of incidence and imaging the reflected light, and the features of the extracted region Is an apparatus for automatically generating parameters used in a board inspection apparatus that inspects the mounting state of the component depending on whether or not a predetermined determination condition is satisfied,
Image acquisition means for acquiring a plurality of target images obtained by imaging components to be detected by inspection and a plurality of exclusion images obtained by imaging components to be excluded by inspection;
Mapping means for mapping the color of each pixel of the target image as a target point and mapping the color of each pixel of the exclusion image as a excluded point, respectively, in a color space;
Color range search means for obtaining a color range that divides the color space and that maximizes the difference between the number of target points included therein and the number of excluded points;
Color condition setting means for setting the obtained color range as a color condition used in substrate inspection,
The image acquisition means acquires a solder region in a non-defective product image with a normal component mounting position as the target image, and acquires a solder region in a defective product image with a non-normal component mounting position as the exclusion image. Parameter setting device. A region satisfying a predetermined color condition is extracted from an image obtained by irradiating a component mounted on the board with light of multiple colors at different angles of incidence and imaging the reflected light, and the features of the extracted region Is an apparatus for automatically generating parameters used in a board inspection apparatus that inspects the mounting state of the component depending on whether or not a predetermined determination condition is satisfied,
Image acquisition means for acquiring a plurality of target images obtained by imaging components to be detected by inspection and a plurality of exclusion images obtained by imaging components to be excluded by inspection;
Mapping means for mapping the color of each pixel of the target image as a target point and mapping the color of each pixel of the exclusion image as a excluded point, respectively, in a color space;
Set a color range that divides the color space, extract a pixel region that satisfies the color range from each of the target image and the excluded image, and create a feature amount histogram for the feature amount of the pixel region, Color range search means for obtaining a color range that maximizes the degree of separation by repeating a color range search process for calculating the degree of separation between the frequency distribution of the target image and the frequency distribution of the excluded image in the feature amount histogram; ,
Color condition setting means for setting the obtained color range as a color condition used in substrate inspection;
A parameter setting device for a substrate inspection apparatus comprising: The color space is a multidimensional color space consisting of at least a saturation axis and a lightness axis for hues that are included in the target image and tend to be hardly included in the excluded image,
11. The parameter setting device for a substrate inspection apparatus according to claim 10, wherein, in the color range search process, a saturation range is fixed and only a brightness range is changed to obtain a color range in which the degree of separation is maximized. A region satisfying a predetermined color condition is extracted from an image obtained by irradiating a component mounted on the board with light of multiple colors at different angles of incidence and imaging the reflected light, and the features of the extracted region Is an apparatus for automatically generating parameters used in a board inspection apparatus that inspects the mounting state of the component depending on whether or not a predetermined determination condition is satisfied,
Image acquisition means for acquiring a plurality of target images obtained by imaging components to be detected by inspection and a plurality of exclusion images obtained by imaging components to be excluded by inspection;
Mapping means for mapping the color of each pixel of the target image as a target point and mapping the color of each pixel of the exclusion image as a excluded point, respectively, in a color space;
Color range search means for obtaining a color range that divides the color space and that maximizes the difference between the number of target points included therein and the number of excluded points;
Color condition setting means for setting the obtained color range as a color condition used in substrate inspection,
The image acquisition means acquires a component mounting region in a non-defective image with a normal component mounting position as the target image, and acquires a component mounting region in a defective product image with a non-normal component mounting position as the exclusion image. Device parameter setting device. A region satisfying a predetermined color condition is extracted from an image obtained by irradiating a component mounted on the board with light of multiple colors at different angles of incidence and imaging the reflected light, and the features of the extracted region Is an apparatus for automatically generating parameters used in a board inspection apparatus that inspects the mounting state of the component depending on whether or not a predetermined determination condition is satisfied,
Image acquisition means for acquiring a plurality of target images obtained by imaging components to be detected by inspection and a plurality of exclusion images obtained by imaging components to be excluded by inspection;
Mapping means for mapping the color of each pixel of the target image as a target point and mapping the color of each pixel of the exclusion image as a excluded point, respectively, in a color space;
Color range search means for obtaining a color range that divides the color space and that maximizes the difference between the number of target points included therein and the number of excluded points;
Color condition setting means for setting the obtained color range as a color condition used in substrate inspection,
The image acquisition means includes
When solder having the property of diffusing and reflecting light is used, a component mounting area in a non-defective product image in which the component mounting position is normal is acquired as the target image, and a defective product image in which the component mounting position is not normal The component mounting area at is acquired as the exclusion image,
In other cases, the parameter setting device of the board inspection apparatus acquires the solder area in the non-defective product image as the target image and acquires the solder area in the defective product image as the exclusion image. 14. The parameter setting device for a board inspection apparatus according to claim 12, wherein the image acquisition means acquires a board area around a part in the non-defective image in addition to a part mounting area in the defective product image as the exclusion image. 14. The board inspection according to claim 12 or 13, wherein the image acquisition means acquires, as the exclusion area, a board area in a bare board image obtained by imaging a bare board before component mounting in addition to a part mounting area in the defective product image. Device parameter setting device. A feature amount histogram generating means for extracting a pixel region that satisfies the color condition from each of the target image and the excluded image and creating a feature amount histogram for a feature amount of the pixel region;
Threshold determination means for calculating a threshold for separating the feature amount of the target image and the feature amount of the excluded image based on the frequency distribution of the feature amount histogram;
16. The parameter setting device for a substrate inspection apparatus according to claim 9, further comprising determination condition setting means for setting the calculated threshold value as a determination condition used in substrate inspection. A storage unit for storing color conditions and determination conditions set by the parameter setting device according to claim 16;
A light projecting means for irradiating light of a plurality of colors at different incident angles on a mounting component on the substrate;
A region extracting means for extracting a region that satisfies the color condition from an image obtained by imaging the reflected light;
An inspection means for inspecting the mounting state of the component based on whether or not the feature value of the extracted region satisfies the determination condition;
A board inspection apparatus comprising:

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