JP2007309808A - Method and system for detecting position of object - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and device for detecting the position of an object capable of improving precision of pattern matching, and capable of precisely detecting the position of the object. <P>SOLUTION: The substrate 10 is photographed with a substrate recognition camera, part 10a of the image is registered as a template image A. If there exists difference between the fixing angles of the camera when the template image is taken photographed and when the substrate image for pattern matching is taken photographed, the registered template image A is corrected corresponding to the difference between the fixing angles so that the position detection may be performed by the pattern matching with the corrected template image. By this constitution, even in the case the fixing angle is including an error, the highly precise position detection by the pattern matching can be performed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a position detection method and apparatus for an object, and more specifically, registers a feature of an object such as a printed circuit board as a template, and detects the position of the object by pattern matching and Relates to the device.

  Conventionally, in an electronic component mounting machine, a printed circuit board is carried into the apparatus in order to mount the electronic component on the substrate with high accuracy, and the printed circuit board is fixed at the mounting position as a preparation before mounting, and printed on the substrate. Recognize the mark, correct the misalignment of the printed circuit board and print misalignment, and mounted the electronic components accurately. Also, if there is no reference mark on the printed circuit board, register a characteristic mark, pattern, etc. as a template, and detect the position of the board with high accuracy by performing pattern matching with the printed circuit board that is sequentially loaded using this image. Electronic parts were mounted (Patent Documents 1 and 2).

In addition, machines that position and work on printed boards such as screen printing machines and adhesive application devices other than electronic component mounting machines also use the same position detection method.
JP-A-11-337311 JP 2001-124518 A

  However, when registering a characteristic mark or pattern of a printed circuit board as a template, the registered template is used in an apparatus or station that uses another image pickup device due to an error in the field of view magnification caused by a camera mounting error or an inclination of the image pickup device. There is a problem that the pattern matching cannot be performed accurately because the size and inclination of the template image are different.

  In addition, registering a feature part template for each device or camera unit takes time and effort for the operator, and the image processing device must also register each template data, resulting in a large loss of cost and work time. there were. In Patent Document 2, the optical magnification of an image processing apparatus of a different machine is read and the registered pattern is converted. However, since the inclination information of each imaging apparatus is not taken into account, there is a problem that recognition accuracy causes a problem. It was.

  The present invention has been made in view of such problems, and provides an object position detection method and apparatus capable of improving the accuracy of pattern matching and accurately detecting the position of the object. Is an issue.

The present invention
An object position detection method for detecting the position of an object by pattern matching,
An object is imaged by an imaging device, a part of the captured image is registered as a template image,
When imaging a target and performing pattern matching based on the template image, the difference between the mounting angle of the imaging device when the template image is acquired and the mounting angle of the imaging device when imaging the target for pattern matching When there is, the registered template image is corrected according to the difference in the mounting angle, and the position of the object is detected by pattern matching with the corrected template image.

The present invention also provides:
An object position detection device for detecting the position of an object by pattern matching,
Storage means for storing a part of an image of the object imaged by the imaging device as a template image;
Storage means for storing the mounting angle of the imaging device;
When imaging a target and performing pattern matching based on the template image, the difference between the mounting angle of the imaging device when the template image is acquired and the mounting angle of the imaging device when imaging the target for pattern matching When there is, the stored template image is corrected according to the difference in the mounting angle, and the position of the object is detected by pattern matching with the corrected template image.

  According to the present invention, when there is a difference between the mounting angle of the imaging device when the template image is acquired and the mounting angle of the imaging device when capturing an object for pattern matching, the template image corresponding to the difference is displayed. Since correction is performed to perform pattern matching, even if there is an attachment angle error of the imaging device, good pattern matching can be performed and the position of the object can be detected with high accuracy.

  Further, since the template image can be shared by various devices, an effect that the management of the template image becomes easy can be obtained.

  Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

  FIG. 1 is a diagram schematically showing a component mounter (mounter) 1 for mounting electronic components (hereinafter referred to as components) on a printed circuit board. As shown in the figure, a suction head 13 having a suction nozzle 13a is attached to an X-axis movement mechanism 11 so that it can move in the X-axis direction, and the X-axis movement mechanism 11 can move in the Y-axis direction. In this way, the suction head 13 can be moved in the X and Y axis directions.

  The component 2 supplied from the component supply device 14 is sucked by the suction head 13 and mounted at a predetermined position of the substrate 10 that is transported along the transport path 15. A substrate recognition camera 17 is mounted on the suction head 13 to recognize the displacement of the substrate, and a component recognition camera 16 is attached to the bottom of the component mounting machine 1 to recognize the suction posture of the component. ing.

  In addition, an operation monitor 18 for displaying the operation state of the apparatus and the like is provided at the upper front of the component mounter 1, and a control unit 19 for controlling the entire apparatus and performing image processing is provided in the main body. Yes. The control unit 19 processes the image of the printed circuit board 10 taken by the board recognition camera 17 to calculate the board position deviation, and calculates the part suction deviation based on the part image taken by the part recognition camera 16. By correcting these deviations, the component 2 is mounted at a predetermined position on the printed circuit board 10 in a correct posture.

  FIG. 2 shows the configuration of the control system of the component mounting machine 1. The control unit 19 in FIG. 1 includes the controller 20, the image processing device 27, the storage device 30, and the like in FIG.

  The controller 20 includes a microcomputer (CPU) that controls the entire apparatus, a RAM, a ROM, and the like, and an X-axis motor 21 that is a drive source of the X-axis moving mechanism 11 and a Y-axis that is a drive source of the Y-axis moving mechanism 12. The motor 22 and the Z-axis motor 23 that moves the suction nozzle 13a up and down in the Z-axis direction (height direction) and the θ-axis motor 24 that rotates the suction nozzle 13a around the nozzle center axis (suction axis) are controlled.

  The controller 20 turns on the board illumination light source 25 to illuminate the board 10 when taking an image of the printed board 10 with the board recognition camera 17, and takes part illumination when taking an image of the component 2 sucked by the suction nozzle 13 a. The light source 26 is turned on to illuminate the component 2.

  The image processing device 27 includes an A / D converter 27a, a CPU 27b, and storage means such as an image memory 27c, a template memory 27d, and a data memory 27e. The image processing device 27 includes the substrate 10 captured by the substrate recognition camera 17 serving as an imaging device. The analog image signal is converted into a digital signal by the A / D converter 27a and stored in the image memory 27c. The CPU 27 b detects the position of the substrate 10 by detecting the position of the substrate mark formed on the substrate 10. When the substrate mark is not printed on the substrate 10, the position of the substrate 10 is recognized by pattern matching with the template image stored in the template memory 27d as will be described later.

  The analog image signal of the component 2 captured by the component recognition camera 16 is converted into a digital signal by the A / D converter 27a and stored in the image memory 27c, and the CPU 27b is sucked based on the component image data. The position shift of the component center and the shift of the suction angle with respect to the suction center of the component 2 are recognized.

  Note that, depending on the model, a laser unit including a laser light emitting unit 35 and a laser light receiving unit 36 is mounted on the suction nozzle 13 in order to recognize a component that does not require highly accurate recognition. The shadow of the component 2 irradiated with the laser light generated from the laser emitting unit 35 is received by the laser receiving unit 36, and the component center and the component suction angle are detected.

  The controller 20 corrects the mounting position of the component 2 based on the recognized positional deviation of the board and the suction displacement of the component, and moves the suction head 13 to the corrected mounting position to mount the component 2.

  The keyboard 28 and mouse 29 are used for inputting data such as component data. The storage device 30 is configured by a flash memory or the like, and is used to store component data input by the keyboard 28 and the mouse 29, component data supplied from a host computer (not shown), and the like.

  The display device 31 corresponds to the monitor 18 in FIG. 1 and displays, on a screen 31a, component data, calculation data, an image of the substrate 10 captured by the substrate recognition camera 17, an image of the component 2 captured by the component recognition camera 16, and the like. indicate.

  In order to avoid complication, the substrate illumination light source 25, the component illumination light source 26, the laser light emitting unit 35, the laser light receiving unit 36, the keyboard 28, the mouse 29, etc. shown in FIG. 2 are not shown in FIG. Yes.

  When the substrate 10 transported along the transport path 15 is transported to a predetermined component mounting position, the substrate 10 stops and is fixed at that position. At this time, since the substrate 10 is not necessarily fixed at the regular position, the substrate 10 is imaged by the substrate recognition camera 17 by moving the suction head 13 to the substrate position, and the substrate 10 is processed by processing the image. Positioning (substrate position detection) is performed, and when there is a positional deviation in the substrate, this positional deviation is corrected.

  In the present invention, the substrate is positioned by pattern matching. For this purpose, a positioning pattern is registered in advance in the template memory 27d of the image processing apparatus 27 as a template image. When a specific positioning mark is formed on the substrate, an image of the positioning mark is registered in the memory 27d as a template image. On the other hand, when there is no specific positioning mark, as shown in FIG. In addition, a circuit pattern or a characteristic circuit mark on the substrate included in an arbitrary region 10a in the substrate 10 is used as a positioning template. Therefore, the board 10 is imaged by the board recognition camera 17, an area 10a where a circuit pattern or a characteristic circuit mark exists is set, an image in the area 10a is cut out, and this is shown in FIG. The template image A is registered in the template memory 27d. At that time, the position data (coordinate values) of the area 10a from which the template image A was acquired, the optical and mechanical specifications of the substrate recognition camera 17 that captured the template image A, the imaging conditions such as the optical magnification (scaling), and Data such as the attachment angle of the substrate recognition camera 17 to the suction head 13 is registered in the data memory 27e in association with the template image A. These data may be stored in the storage device 30 and loaded into the data memory 27e.

  In such a configuration, the flow of detecting the position of the substrate will be described along the flow of FIGS.

  First, in the component mounter 1, the substrate 10 is fixed at the component mounting position (step S1), the suction head 13 is moved, and the substrate recognition camera 17 images the substrate 10. An image of the substrate 10 on the display device 31 at this time is shown in FIG. The operator sees this image and sets a region 10a having a characteristic part or a characteristic pattern (step S2), and the image in this region 10a is used as a template image A as shown in FIG. Capture (step S3) and store it in the template memory 27d (step S4). At this time, the optical magnification (scaling) of the board recognition camera 17 that images the board 10 and the mounting angle of the board recognition camera 17 are stored in the data memory 27e in association with the template image A.

  Here, the mounting angle of the substrate recognition camera 17 is such that the rectangular imaging surface is horizontal (imaging optical axis is vertical) and the substrate recognition camera 17 is attached to the suction head 13, and one side of the imaging surface is the X axis. Alternatively, it is an angle formed with respect to the Y axis. For example, the X axis or the Y axis is moved, the same part on a straight line parallel to the X axis or the Y axis is imaged, and the inclination of the straight line is detected by image processing. Thus, the mounting angle of the board recognition camera 17 can be obtained. Further, the mounting angle of the board recognition camera 17 may be obtained by moving the X axis or the Y axis to capture a circular mark or the like.

  Next, for example, when detecting the position of the same board with another component mounting machine having different or the same board recognition camera attached to the suction head, a template for positioning is not newly registered. The template image A stored in step S4, the optical magnification information of the camera at the time of image capturing, and the camera mounting angle are read (step S11 in FIG. 6), and the magnification and mounting angle of the board recognition camera in another component mounting machine. Based on the above, the template image A is converted to create a new template image.

  Specifically, for example, the template image A shown in FIG. 3B has a board position detection in a component mounter machine equipped with a board recognition camera having a visual field of 6 square mm and an attachment angle of −0.1 degrees. When the template matching is performed by another component mounting machine equipped with a board recognition camera having a visual field of 6.6 square mm and an attachment angle of 0.3 degrees, the template image A is 6.6. The template image is enlarged and rotated as shown in FIG. 4B by enlarging the image by 6 times and performing inclination correction of (0.3 − (− 0.1)) degree by a conversion method such as affine transformation. B is created (step S12).

  The template image B created in this way corresponds to the template image created from the area 10a of the image of the board 10 shown in FIG. 4A taken by the board photographing camera of the other component mounting machine. (Step S13), and using this template image B, the position of the board in another component mounter is detected by pattern matching between the board image shown in FIG. Positioning) is performed (step S14).

  As described above, by correcting the template image in consideration of the optical magnification information of the camera to be newly positioned and the mounting angle information of the camera, pattern matching between the image captured by the different camera and the corrected template image is performed. This makes it possible to maintain position detection accuracy by pattern matching on other component mounting machines and to share templates with various machines or devices, thus simplifying the template creation process. And the management of the template image becomes easy.

  In the above-described embodiment, the template image is corrected or converted in consideration of the optical magnification information of the camera and the mounting angle information of the camera. However, if the optical magnification is set to be the same, the camera is attached. The template image may be corrected or converted in consideration of only the angle information.

  In the above-described embodiment, the printed circuit board on which the component is mounted is exemplified as the object. However, the object is not limited to this, and the object can be a component mounted on the component mounting machine. It can also be applied to component recognition based on the above (component position detection). In this case, since the camera is a component recognition camera, based on the optical magnification and / or mounting angle of the component recognition camera 16 in the component mounter, the template image already created in another component execution machine is converted. And pattern matching is performed using the converted template image.

It is the perspective view which outlined the external appearance of the component mounting machine. It is the block diagram which showed the control system of the component mounting machine. It is explanatory drawing explaining the state which takes in a template image from the board | substrate image imaged with the component mounting machine. It is explanatory drawing which shows the image of the board | substrate imaged with the other component mounting machine. It is a flowchart explaining the flow of taking in a template image. It is a flowchart which shows the flow of the pattern matching by correction | amendment of a template image and the corrected template image.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Printed circuit board 13 Adsorption nozzle 16 Component recognition camera 17 Board | substrate recognition camera 27 Image processing apparatus

Claims (4)

An object position detection method for detecting the position of an object by pattern matching,
An object is imaged by an imaging device, a part of the captured image is registered as a template image,
When imaging a target and performing pattern matching based on the template image, the difference between the mounting angle of the imaging device when the template image is acquired and the mounting angle of the imaging device when imaging the target for pattern matching When there is a target object, the registered template image is corrected according to the difference in the mounting angle, and the target object position is detected by pattern matching with the corrected template image.   If there is a difference between the optical magnification of the imaging device when the template image is acquired and the optical magnification of the imaging device when imaging an object for pattern matching, further correction of the template image according to the difference in the optical magnification The method for detecting a position of an object according to claim 1, wherein: An object position detection device for detecting the position of an object by pattern matching,
Storage means for storing a part of an image of the object imaged by the imaging device as a template image;
Storage means for storing the mounting angle of the imaging device;
When imaging a target and performing pattern matching based on the template image, the difference between the mounting angle of the imaging device when the template image is acquired and the mounting angle of the imaging device when imaging the target for pattern matching An object position detecting apparatus that corrects the stored template image according to the difference in the attachment angle and detects the position of the object by pattern matching with the corrected template image.   If there is a difference between the optical magnification of the imaging device when the template image is acquired and the optical magnification of the imaging device when imaging an object for pattern matching, further correction of the template image according to the difference in the optical magnification The object position detection apparatus according to claim 3, wherein:

Images