WO2017080294A1

WO2017080294A1 - Board card image splicing method and processing apparatus and system

Info

Publication number: WO2017080294A1
Application number: PCT/CN2016/098225
Authority: WO
Inventors: 廖明熙
Original assignee: 广州视源电子科技股份有限公司
Priority date: 2015-11-09
Filing date: 2016-09-06
Publication date: 2017-05-18
Also published as: CN105335931A

Abstract

Disclosed are a board card image splicing method and processing apparatus and system. The method comprises: acquiring a local image of a board card collected by a camera apparatus (S100); after distortion correction is performed on various local images, respectively tailoring various edges of each of the partial images, so as to obtain standard partial images corresponding to the various partial images (S110); and according to the relative position relationship of the various standard local images on the board card, splicing the standard partial images to form a board card image (S120). The board card image splicing method is not limited by the size of a board card, and a tailored standard local image can be directly spliced according to the relative position relationship thereof on the board card so as to form a board card image, so that the image splicing is simpler and more efficient.

Description

Card image splicing method, processing device and system

Technical field

The invention relates to the field of automatic optical detection, in particular to a card image splicing method, a processing device and a system.

Background technique

The board is an important device with data acquisition function and integrated data input/output. It is widely used in many fields such as automation machinery, electronics industry, security monitoring and computer, and the placement and solder joints of components on the board. The quality of the board will affect the overall performance of the board. Therefore, in actual industrial production, the components and solder joints of the board must be tested to eliminate defective or faulty boards. In the field of board detection technology, the automatic optical detection system acquires the image of the detected board through a high-precision camera, and combines the image processing technology to analyze the difference between the image of the detected board and the standard board image, thereby detecting the board. The defect is that the system has the advantages of high degree of automation, high accuracy, easy operation, no damage to the board being tested, and thus is widely used for the detection of boards. However, for the automatic optical detection system, when the size of some detected boards is large, if the camera is still used for framing, the overall image of the detected board may not be obtained due to the limited field of view of the camera. It even causes the obtained image of the detected board to be distorted, and thus loses more detailed information of the board image, which is not conducive to efficient and accurate detection and analysis of the board.

Summary of the invention

Based on this, it is necessary to provide a card image splicing method, processing device and system for the overall and undistorted image problem of the large-sized card in the automatic optical detection system.

The embodiment of the invention provides a card image splicing method, a processing device and a system, which are respectively:

A method for stitching a card image, comprising the following steps:

Acquiring a partial image of the card acquired by the camera device, wherein the partial image is acquired by the camera device at a fixed distance interval in the same direction, and the partial images adjacent in the same direction have a coincident region;

After performing distortion correction on each of the partial images, each side of each of the partial images is separately cropped to obtain a standard partial image corresponding to each of the partial images;

The standard partial images are spliced to form a card image according to the relative positional relationship of each of the standard partial images on the card.

A processing device for stitching a card image, comprising:

An acquiring unit, configured to acquire a partial image of a card acquired by the camera device, where the partial image is acquired by the camera device at a fixed distance interval in the same direction, and the partial images adjacent in the same direction have coincidence region;

a processing unit, configured to perform distortion correction on each of the partial images, and perform trimming on each side of each of the partial images to obtain a standard partial image corresponding to each of the partial images;

a splicing unit for splicing the standard partial images to form a card image according to the relative positions of the respective partial partial images.

A card image splicing system, comprising: a platform device, an imaging device, a control device for controlling relative movement of the camera device and the platform device, and the above-mentioned processing device for splicing a card image, the camera device Connected to the processing device,

The platform device is configured to carry a board;

The camera device is configured to collect a partial image of the card;

The control device is configured to control the camera device to acquire partial images of the card according to a fixed distance interval in the same direction, and the partial images adjacent in the same direction have overlapping regions.

The board image splicing method, processing device and system, the partial image of the board is collected by the camera device, and the collected adjacent partial images have overlapping regions in the same direction, and each partial image is separately corrected for distortion, for each The edges of a partial image are cropped, and since the edge portion of the partial image after the distortion correction still has distortion, when the cropping is performed, the edge portion of the partial image overlapping region where the distortion occurs is trimmed, and the standard portion obtained after the clipping is obtained. The image just happens to be stitched together to form a complete board image. Since the distortion of each standard partial image constituting the image of the board is corrected, the board image formed according to the standard partial image splicing has high precision, and the board image splicing method and processing device proposed by the present invention and The system is not limited by the size of the board, and for larger boards it is still possible to obtain higher precision images for inspection. In addition, the mark obtained after cutting The quasi-local image can be directly spliced to form the card image according to the relative positional relationship on the board without complicated image feature point matching analysis process, and the image cutting process and the splicing process are more simple and efficient, so the present invention The proposed card image splicing method, processing device and system have high image splicing speed and efficiency.

DRAWINGS

1 is a schematic flow chart of a method for stitching a card image in one embodiment;

2 is a schematic diagram of a partial image of a board of a camera device;

3 is a schematic diagram of a partial image of a rectangular board captured by a camera device;

4 is a partial image diagram of a board before and after distortion correction;

FIG. 5 is a schematic diagram of cropping of a partial image in one embodiment; FIG.

6 is a schematic diagram of cropping of a partial image in one embodiment;

7 is a schematic diagram of a camera device collecting partial images of boards at different positions;

Figure 8 is a schematic view showing a partial image mosaic of the card;

9 is a schematic flow chart of a method for stitching a card image in one embodiment;

Figure 10 is a schematic view of the position of the marked point;

FIG. 11 is a schematic structural diagram of a processing apparatus for board image stitching in one embodiment; FIG.

12 is a schematic structural diagram of a processing apparatus for board image stitching in one embodiment;

FIG. 13 is a schematic structural diagram of a card image splicing system in one embodiment.

detailed description

The technical solutions of the present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments.

In one embodiment, referring to FIG. 1, a method for stitching a card image includes the following steps:

S100 acquires a partial image of a card acquired by the camera device;

In this step, referring to the schematic diagram of the partial image of the board captured by the camera device shown in FIG. 2, the camera device is located directly above the card, and the camera device collects the obtained partial images at a fixed distance interval in the same direction. To illustrate this step in detail, taking the rectangular board shown in Figure 3 as an example, in a direction parallel to one side of the board (such as the AB side), the camera captures a partial image of the board every other fixed distance interval. Each part of the captured board of the camera is aligned with the partial image of the board acquired last time and along the direction of the AB side of the board until all partial images of the board are collected, such as Figure 3. The partial image a ₁ b ₁ c ₁ d ₁ and the partial image a ₂ b ₂ c ₂ d ₂ shown therein are aligned with each other and are along the direction of the AB side of the card; meanwhile, the camera is fixed in the same direction The partial images of the distances collected in the same direction have overlapping areas. Still taking the rectangular board shown in FIG. 3 as an example, the camera device collects the boards in the direction parallel to the AB side of the board. a partial image, and two adjacent partial images have a certain overlapping area, as shown in the coincident area a ₂ b ₁ c ₁ d ₂ in FIG. ₃ , the size of the overlapping area is the same as that used by the camera when acquiring a partial image. Fixed distance interval Related to the size, the smaller the distance interval, the greater the overlap region of the partial image. Similarly, when the camera captures a partial image of the card along the AD side of the card, the acquisition mode is the same as that of the AB side of the card, and is collected according to the fixed distance interval in the same direction. The fixed distance interval used by the camera to collect partial images along the AB side and the AD side of the card may be different.

After performing the distortion correction on each of the partial images, S110 separately trims each side of each of the partial images to obtain a standard partial image corresponding to each of the partial images;

In the actual working process of the camera device, due to the optical design of the camera lens itself, the optical system of the camera device does not work accurately on the principle of idealized aperture imaging, so that the object point in the object space is in the image space. There is an optical aberration between the actual image point and the ideal image point, which causes image distortion. When the local image is corrected for distortion, the gray interpolation method can be adopted. The basic idea is to first establish a mathematical model of geometric correction, then determine the model parameters by using known conditions, and finally correct the image containing the distortion according to the model. It is usually divided into two steps: image space coordinate transformation. Firstly, the mapping relationship between image pixel coordinates and object space corresponding point coordinates is established, the unknown parameters in the mapping relationship are solved, and then the pixel coordinates of the image are corrected according to the mapping relationship; The gray value is used to assign the corresponding gray value to the pixel after the spatial transformation, so as to restore the gray value of the original position, thereby realizing the distortion correction of the image. Partial image display of the board before and after distortion correction as shown in Figure 4. Intention, after the distortion correction, the partial image of the board is closer to the real board image.

Each side of each partial image after the distortion correction is separately cropped to obtain a standard partial image corresponding to each partial image. After each partial image of the board is corrected for distortion, the edge portion of the partial image will have a large distortion, and the edge portion with distortion is not conducive to the detection and analysis of the board, so each part of the partial image corrected by the distortion is corrected. The cropping is performed separately to remove the edge portion of the partial image, thereby improving the accuracy of the partial image for board detection. In the case of cropping the partial image after distortion correction, in order to ensure that the selected crop width is both in line with actual needs and can improve the efficiency of board image stitching, different crop widths can be selected according to different lens parameters of the camera device, because they have different The distortion coefficient of the lens device of the lens parameter is different. After the distortion correction of the partial image, the size of the edge portion of the distortion may be different, so that the size of the standard partial image obtained by cropping the partial image is different, so the lens parameter of the camera device is used. As a reference and basis for the cutting width, the processing method of the partial image of the board with different distortion conditions is fully considered.

As a specific implementation manner, when each side of each partial image is separately cut, the cutting width of each side is half of the width of the overlapping area corresponding to each side. Here, only two partial images acquired by the imaging device, the partial image a ₁ b ₁ c ₁ d ₁ and the partial image a ₂ b ₂ c ₂ d ₂ will be described as an example. Referring to FIG. 5, the partial image a ₁ b ₁ c ₁ d ₁ After cropping, a corresponding standard partial image 1256 is obtained, and after the partial image a ₂ b ₂ c ₂ d ₂ is cropped, a corresponding standard partial image 2345 is obtained, and the area a shown in FIG. ₂ b ₁ c ₁ d ₂ is a coincident region of the partial image a ₁ b ₁ c ₁ d ₁ and the partial image a ₂ b ₂ c ₂ d ₂ when the partial image a ₁ b ₁ c ₁ d ₁ and the partial image a ₂ b _When the clipping width of ₂ c ₂ d ₂ is half of the width of the coincident region (ie, the length of a ₂ b ₁ or d ₂ c ₁ ), the standard partial image 1256 and the standard partial image 2345 can be seamlessly stitched. There is no coincident portion between the standard partial image 1256 and the standard partial image 2345. Similarly, for the cropping of the other edges of the partial image a ₁ b ₁ c ₁ d ₁ and the partial image a ₂ b ₂ c ₂ d ₂ , the half of the width of the overlapping area of the partial image and the other partial images are respectively cut as the corresponding edges. width. In the present embodiment, the width of the partial image overlap region is used as the width of each partial image for cropping, which not only ensures that the corresponding standard partial image can form a complete board image, and does not miss any image information of the card, and avoids The image information is repeatedly displayed due to the coincidence between standard partial images, thereby improving the stitching efficiency of the board image.

As a specific implementation manner, when the partial image of the board acquired by the image capturing apparatus is cropped, the cutting width of each side of each partial image is the same. Referring to the partial image cropping diagram of the card shown in FIG. 6, the overlapping area of the partial image a ₁ b ₁ c ₁ d ₁ and the partial image a ₂ b ₂ c ₂ d ₂ is the area a ₂ b ₁ c ₁ d ₂ . The overlapping area of the partial image a ₁ b ₁ c ₁ d ₁ and the partial image a ₄ b ₄ c ₄ d ₄ is the area a ₄ b ₄ c ₁ d ₁ , the partial image a ₂ b ₂ c ₂ d ₂ and the partial image a ₃ The overlapping region of b ₃ c ₃ d ₃ is the region a ₃ b ₃ c ₂ d ₂ , and the overlapping region of the partial image a ₃ b ₃ c ₃ d ₃ with the partial image a ₄ b ₄ c ₄ d ₄ is the region a ₃ b ₄ c ₄ d ₃ , the widths of the respective overlapping regions are the same, that is, the lengths of a ₄ d ₁ , a ₂ b ₁ , b ₃ c ₂ and c ₄ d ₃ are the same. In the embodiment, each partial image is cropped with the same cutting width, which facilitates processing all partial images of the card collected by the imaging device, and conveniently controls the distance interval adopted by the imaging device, which is beneficial to improve The efficiency of board image stitching.

S120 splices the standard partial images into a card image according to the relative positions of the respective partial partial images.

Since the camera device collects partial images of the card, it is collected according to a certain order rule. As shown in FIG. 7, after the camera device collects a partial image of the card at a certain position, it moves to the next position and continues to collect. The partial images of the board, so the local images obtained by the acquisition have a certain positional relationship with each other, and since each partial image corresponds to only one standard partial image, each standard partial image also has a relative position relationship with each other. When the image is spliced, the standard partial image may be spliced according to the relative positions of the respective partial partial images, and finally the card image is formed, as shown in FIG. 8 , the partial image splicing diagram of the card, the card image can reflect the card Information on all components, solder joints, etc.

Since the distortion of each standard partial image constituting the board image in the above embodiment is corrected, the board image formed according to the standard partial image stitching has high precision, and the board image stitching method has no board. The advantage of card size limitation is that for larger size boards it is still possible to obtain higher precision images for inspection. In addition, the standard partial images obtained after cutting can be directly spliced to form the board image according to their relative positions on the board, without complicated image feature point matching analysis process, and the partial image cutting process and the splicing process are more simple. It is efficient, so the board image stitching method proposed in this embodiment has higher image stitching speed and efficiency.

Generally, the boards have a regular shape, so that the board can be aligned with the field of view of the camera to prevent the partial image captured by the camera from being tilted, thereby facilitating image acquisition and simplifying image acquisition. The process of processing, and therefore, in one of the embodiments of the card image splicing method proposed by the present invention, before the step of acquiring the partial image of the card acquired by the camera device, referring to the flow diagram shown in FIG. 9, the method may further include The following steps for image alignment:

S900 acquires an image of the marked point on the board and performs distortion correction on the image to obtain a first image;

The board used in this step can be a common board with components. In this case, the components on the board are used as marking points. The board used can also be designed with marking points specially designed for this method. Board. The first image of the marked point is a distortion corrected image including the image of the marked point, for example, before the first image of the marked point on the board is acquired by the camera, the image acquired by the camera is first corrected by the camera calibration technique. Distortion, the acquired image is restored to a real plane, thereby providing an undistorted image for board image calibration, improving the accuracy of board image alignment.

After the position of the board is changed, the S910 acquires the image of the marked point again and performs distortion correction on the image to obtain a second image.

After acquiring the first image of the marked point on the board, changing the position of the board, that is, changing the position of the marked point, acquiring the image of the marked point again and performing distortion correction on the image to obtain a second image, that is, the second image includes the mark Distorted image after the image of the point. When changing the position of the board, the xy coordinate system is established with the two adjacent sides of the board. Referring to FIG. 10, it is assumed that the first image S ₀ of the marked point is located at the origin O(0, 0) of the coordinate system, and is changed. After the position of the board, the second image S _{1 of the} marked point moves to the point (x1, y1), and the moving distance of the marked point is

S920: Obtain an offset trajectory of the marker point according to the first image and the second image, and calculate an angle between the offset trajectory and an edge of the first image or the second image;

Taking the second image of the marked point shown in FIG. 10 as an example, AB, BC, CD, and DA are respectively four sides of the second image, and the actual offset of the marked point can be obtained in the coordinate system established in step S910. The track is a line segment

Since it is difficult to move the marker point completely parallel along the x-axis of the card, in practice

There may be a certain angle α with the x-axis, and the angle α is the angle between the offset track of the mark point and the AB side of the second image, and the angle α can be calculated according to the specific coordinates of the mark points S ₀ and S ₁ . It is numerically equal to α=arctan(y ₁ /x ₁ ). Here, only the AB side of the second image is taken as an example. Based on the same principle, the offset trajectory of the marker point is calculated in the same manner as the angle between the other sides of the second image.

S930 adjusts the position of the camera device or the card according to the angle to make the offset The trajectory is parallel or perpendicular to the sides of the first image or the second image.

After calculating the angle α between the offset trajectory of the marker point and the AB edge of the second image, the position of the camera or the card is adjusted according to the angle, so that the offset trajectory of the marker point is parallel to the AB edge of the second image or the DA side Vertically, for example, by rotating the board to reduce y ₁ or the like, the board is finally aligned with the camera. In the detailed description of each step in the embodiment, only the x-axis direction of the alignment card and the second image of the marked point are taken as an example, but it should be noted that the above method is also fully applicable to the board y. The axial direction or the alignment of the first image using the marked points.

Correspondingly, the present invention provides a processing apparatus for board image stitching. In one embodiment, referring to FIG. 11, the processing apparatus for board image stitching includes an acquisition unit 1100 connected in sequence, and processing. Unit 1110 and splicing unit 1120,

The acquiring unit 1100 is configured to acquire a partial image of a card acquired by the camera device, where the partial image is acquired by the camera device at a fixed distance interval in the same direction, and the partial image adjacent in the same direction has Coincident area

The processing unit 1110 is configured to perform, after performing distortion correction on each of the partial images, performing trimming on each side of each of the partial images to obtain a standard partial image corresponding to each of the partial images;

The splicing unit 1120 is configured to splicing the standard partial images to form a card image according to the relative positions of the respective partial partial images.

Each unit will be described in detail below:

(1) The acquiring unit 1100 acquires a partial image of the card acquired by the camera device, and the partial image is acquired by the imaging device at a fixed distance interval in the same direction, and the adjacent partial images in the same direction have overlapping regions. The camera device collects a partial image of the card according to a fixed distance interval in the same direction. The partial image of the card captured by the camera device is a partial image obtained by the camera device at a fixed distance interval in the same direction. To illustrate this step in detail, taking the rectangular board shown in Figure 3 as an example, in a direction parallel to one side of the board (such as the AB side), the camera captures a partial image of the board every other fixed distance interval. Each part of the captured board of the camera is aligned with the partial image of the board acquired last time and along the direction of the AB side of the board until all partial images of the board are collected, such as Figure 3. a partial image shown in FIG. _{_{_₁}} b ₁ c ₁ d ₁ and the partial image _{_{_{_{a 2 b 2 c 2 d 2}}}} , and both are aligned with one another along the direction of the edge AB of the board; while fixing an imaging apparatus according to the same direction The partial images of the distances collected in the same direction have overlapping areas. Still taking the rectangular board shown in FIG. 3 as an example, the camera device collects the boards in the direction parallel to the AB side of the board. a partial image, and two adjacent partial images have a certain overlapping area, as shown in the coincident area a ₂ b ₁ c ₁ d ₂ in FIG. ₃ , the size of the overlapping area is the same as that used by the camera when acquiring a partial image. Fixed distance interval The size is related, and the smaller the distance interval, the larger the overlapping area of the partial image. Similarly, when the camera captures a partial image of the card along the AD side of the card, the acquisition mode is the same as that of the AB side of the card, and is collected according to the fixed distance interval in the same direction. The fixed distance interval used by the camera to collect partial images along the AB side and the AD side of the card may be different.

(2) The processing unit 1110 performs distortion correction on the partial image of the board acquired by the acquiring unit 1100, and then trims each side of each partial image to obtain a standard partial image corresponding to each partial image. In the actual working process of the camera device, due to the optical design of the camera lens itself, the optical system of the camera device does not work accurately on the principle of idealized aperture imaging, so that the object point in the object space is in the image space. There is an optical aberration between the actual image point and the ideal image point, which causes image distortion. When the processing unit 1110 performs distortion correction on the partial image, the gray interpolation method may be adopted. The basic idea is to first establish a mathematical model of the geometric correction, then determine the model parameters by using known conditions, and finally correct the image containing the distortion according to the model. The method is generally divided into two steps: image space coordinate transformation. Firstly, the mapping relationship between the pixel coordinates of the image and the coordinate of the object corresponding point is established, the unknown parameters in the mapping relationship are solved, and then the coordinates of each pixel of the image are corrected according to the mapping relationship; The gray value of each pixel is determined, and the spatially transformed pixel is given a corresponding gray value to restore the gray value of the original position, thereby realizing distortion correction of the image.

The processing unit 1110 respectively trims each side of each partial image after the distortion correction to obtain a standard partial image corresponding to each partial image. After each partial image of the card is subjected to distortion correction, the edge portion of the partial image may have a large distortion, and the edge portion with distortion may be disadvantageous for detecting and analyzing the card, so the processing unit 1110 passes the distortion corrected portion. Each side of the image is cropped separately to remove the edge portion of the partial image, thereby improving the partial image for board detection. accuracy. When the processing unit 1110 performs the cropping of the distortion-corrected partial image, the processing unit 1110 may select different according to different lens parameters of the camera device, in order to ensure that the selected cropping width meets the actual requirements and the board image image splicing efficiency is improved. The clipping width is different because the distortion coefficient of the camera device with different lens parameters is different. After the distortion correction of the partial image, the size of the edge portion of the distortion may be different, so that the size of the standard partial image obtained by cropping the partial image is different, so Taking the lens parameters of the camera as the reference and basis of the cutting width, the processing method of the partial image of the board with different distortion conditions is fully considered.

As a specific implementation manner, when the processing unit 1110 separately trims each side of each partial image, the cutting width of each side of the processing unit 1110 is half of the width of the overlapping area corresponding to each side. Here, only two partial images acquired by the imaging device, the partial image a ₁ b ₁ c ₁ d ₁ and the partial image a ₂ b ₂ c ₂ d ₂ will be described as an example. Referring to FIG. 5, the processing unit 1110 is After the partial image a ₁ b ₁ c ₁ d ₁ is cropped, a corresponding standard partial image 1256 is obtained, and after the partial image a ₂ b ₂ c ₂ d ₂ is cropped, a corresponding standard partial image 2345 is obtained, as shown in FIG. 5 . The area a ₂ b ₁ c ₁ d ₂ is a coincident region of the partial image a ₁ b ₁ c ₁ d ₁ and the partial image a ₂ b ₂ c ₂ d ₂ when the partial image a ₁ b ₁ c ₁ d ₁ and the partial image When the cutting width of a ₂ b ₂ c ₂ d ₂ is half of the width of the overlapping area (ie, the length of a ₂ b ₁ or d ₂ c ₁ ), the standard partial image 1256 and the standard partial image 2345 can be seamlessly stitched. At this time, there is no coincident portion between the standard partial image 1256 and the standard partial image 2345. Similarly, for the cropping of the other edges of the partial image a ₁ b ₁ c ₁ d ₁ and the partial image a ₂ b ₂ c ₂ d ₂ , the half of the width of the overlapping area of the partial image and the other partial images are respectively cut as the corresponding edges. width. In the present embodiment, the processing unit 1110 uses the half of the width of the partial image overlap region as the width of the cropping of each partial image, which not only ensures that the corresponding standard partial image can form a complete board image, and does not miss any image information of the board. At the same time, the repeated display of image information due to coincidence between standard partial images is avoided, thereby improving the stitching efficiency of the board image.

As a specific implementation manner, when the processing unit 1110 cuts a partial image of the board acquired by the camera, the cutting width of each side of each partial image is the same. Referring to the partial image cropping diagram of the card shown in FIG. 4, the overlapping area of the partial image a ₁ b ₁ c ₁ d ₁ and the partial image a ₂ b ₂ c ₂ d ₂ is the area a ₂ b ₁ c ₁ d ₂ . The overlapping area of the partial image a ₁ b ₁ c ₁ d ₁ and the partial image a ₄ b ₄ c ₄ d ₄ is the area a ₄ b ₄ c ₁ d ₁ , the partial image a ₂ b ₂ c ₂ d ₂ and the partial image a ₃ The overlapping region of b ₃ c ₃ d ₃ is the region a ₃ b ₃ c ₂ d ₂ , and the overlapping region of the partial image a ₃ b ₃ c ₃ d ₃ with the partial image a ₄ b ₄ c ₄ d ₄ is the region a ₃ b ₄ c ₄ d ₃ , the widths of the respective overlapping regions are the same, that is, the lengths of a ₄ d ₁ , a ₂ b ₁ , b ₃ c ₂ and c ₄ d ₃ are the same. In the embodiment, the processing unit 1110 cuts each partial image with the same cropping width, so as to facilitate processing all the partial images of the card captured by the camera device, and at the same time, conveniently control the distance interval adopted by the camera device. It is beneficial to improve the efficiency of board image stitching.

(3) The splicing unit 1120 splices the standard partial images into a card image according to the relative positions of the respective partial partial images. Since the camera device collects partial images of the card, it is collected according to a certain order rule, so the partial images obtained by the camera have a certain positional relationship with each other, and each partial image corresponds to only one standard part. The image, and thus the standard partial images also have a relative positional relationship with each other. When the image splicing is performed, the splicing unit 1120 can splicing the standard partial images according to the relative positions of the respective partial partial images, and finally forming a card image, the card The image can reflect all the components, solder joints and other information on the board.

In the above embodiment of the processing apparatus for board image stitching, since the distortion of each standard partial image constituting the board image is corrected, the board image formed according to the standard partial image stitching has high precision. At the same time, the card image splicing system has the advantage that it is not limited by the size of the board, and a higher-precision image can still obtain a higher-precision image for detection. In addition, the standard partial images obtained after cutting can be directly spliced to form the board image according to their relative positions on the board, without complicated image feature point matching analysis process, and the image cutting process and the splicing process are more convenient and efficient. Therefore, the processing device for board image stitching proposed in this embodiment has higher image stitching speed and better image stitching effect.

Generally, the boards have a regular shape, so that the board can be aligned with the field of view of the camera to prevent the partial image captured by the camera from being tilted, thereby facilitating the process of image acquisition and processing. In the processing apparatus for board image stitching proposed by the present invention, as shown in FIG. 12, a marker point image acquisition unit 1200, an operation unit 1210, and an adjustment unit 1220, which are sequentially connected for image alignment, are further included. among them

The point image acquiring unit 1200 is configured to acquire an image of the mark on the board and perform distortion correction on the image to obtain a first image. After the position of the board is changed, the image of the point is acquired again and The image is corrected for distortion to obtain a second image;

The operation unit 1210 is configured to obtain an offset trajectory of the marker point according to the first image and the second image, and calculate a clip of the offset trajectory and an edge of the first image or the second image. angle;

The adjusting unit 1220 is configured to adjust a position of the camera device or the board according to the angle, so that the offset track is parallel or perpendicular to an edge of the first image or the second image.

Each unit will be described in detail below:

(1) The marker point image acquisition unit 1200 acquires an image of the marker point on the acquisition card and performs distortion correction on the image to obtain a first image, and after the position of the card is changed, acquires the image of the marker point again and the image is Perform distortion correction to obtain a second image. Here, the first image and the second image are both distortion-corrected images including the image of the marker point, except that the specific positions of the marker points in the first image and the second image are different. The board can be a regular board with components. In this case, the components on the board are used as marking points. The board can also be a test board with a specific marking point designed for this device. For example, before the first image of the marked point on the board is acquired by the camera, the distortion of the image acquired by the camera is first corrected by the camera calibration technique, and the acquired image is restored to a real plane, thereby providing distortion-free calibration of the board image. The image improves the accuracy of the board image alignment. After obtaining the first image of the board mark point, changing the position of the board point changes the position of the mark point, and then acquiring the second image of the mark point. When changing the position of the board, the xy coordinate system is established with two adjacent sides of the board. Referring to FIG. 6, it is assumed that the first image S ₀ of the marked point is located at the origin O(0, 0) of the coordinate system, and is changed. After the position of the board, the second image S _{1 of the} marked point moves to the point (x ₁ , y ₁ ), and the moving distance of the marked point is

(2) The arithmetic unit 1210 obtains an offset trajectory of the marker point from the first image and the second image, and calculates an angle between the offset trajectory and the side of the first image or the second image. Taking the second image of the marked point shown in FIG. 10 as an example, AB, BC, CD, and DA are respectively four sides of the second image, and in the above xy coordinate system, the actual offset trajectory of the marked point is obtained as a line segment.

(3) The adjusting unit 1220 adjusts the position of the imaging device or the card according to the angle, so that the offset trajectory is parallel or perpendicular to the side of the first image or the second image. After calculating the angle α between the offset trajectory of the marker point and the AB edge of the second image, the position of the camera or the card is adjusted according to the angle, so that the offset trajectory of the marker point is parallel to the AB edge of the second image or the DA side Vertically, for example, by rotating the board to reduce y ₁ or the like, the board is finally aligned with the camera. In the detailed description of each step in the embodiment, only the x-axis direction of the alignment card and the second image of the marked point are taken as an example, but it should be noted that the method used by the card image alignment device It is also fully applicable to the y-axis direction of the board or the alignment of the first image using the marked points. Through the synergy of the above-mentioned marker point image acquisition unit 1200, the operation unit 1210, and the adjustment unit 1220, the offset trajectory of the front and rear marker points can be changed according to the position of the card, and the corresponding offset trajectory and the first image of the marker point can be calculated or The angle between the sides of the second image, and then adjust the position of the camera or the card according to the angle, and finally align the board with the field of view of the camera to prevent the partial image captured by the camera from being tilted, thereby facilitating Simplify the process of image acquisition and processing.

Meanwhile, the present invention further provides a card image splicing system. In one embodiment, the card image splicing system includes a platform device, a camera device, a control device for controlling relative motion of the camera device and the platform device, and a processing device for splicing a card image, wherein the camera device is connected to the processing device, and the control device can be connected to the camera device and the platform device at the same time or only to any one of the two, or can be disposed on the camera device or Above the platform device, therefore, only the control device is connected to the camera device and the platform device at the same time as an example, as shown in FIG.

a platform device 1300, configured to carry a board;

The camera device 1310 is configured to collect a partial image of the card;

The control device 1320 is configured to control the camera device to collect partial images of the card in a distance interval fixed in the same direction, and the partial images adjacent in the same direction have overlapping regions;

The processing device 1330 is configured to form a card image according to the partial image stitching of the card card collected by the camera device 1310.

In this embodiment, the card is placed on the platform device 1300, the camera device 1310 is opposite to the position of the platform device 1300, and both can perform relative motion under the control of the control device 1320. Specifically, the control device 1320 enables the camera. The device 1310 collects boards according to distances fixed in the same direction. The partial image of the card, that is, the distance between the center points of each of the two adjacent partial images in the same direction is the same, and the adjacent partial images in the same direction have coincident regions. The processing device 1320 obtains a partial image of the card collected by the camera 1300, performs distortion correction and cropping on each partial image, and obtains a corresponding standard partial image, and then splicing each standard partial image to form a card image, the card The image can reflect information of all components, solder joints, and the like on the card; at the same time, the processing device 1320 in this embodiment may further include a point image acquiring unit, an arithmetic unit, and an adjustment for aligning the card with the camera. a unit, wherein the marker point image acquisition unit obtains an offset trajectory of the marker point before and after the change of the board position, and after the calculation unit calculates the angle between the corresponding offset trajectory and the edge of the first image or the second image of the marker point, The adjusting unit adjusts the position of the camera device or the card according to the angle, and finally aligns the card with the field of view of the camera device, thereby preventing the partial image captured by the camera device from being tilted, and aligning the card with the field of view of the camera device. After that, under the control of the control device 1320, the camera 1310 collects various partial images of the board and collects the collected boards. The image processing apparatus 1320 is transmitted to the processing device 1320 is completed respective partial images into the standard images board. In the present embodiment, the image pickup device 1300 can be realized by an industrial area array CCD having a megapixel, and the platform device 1310 can be realized by a mechanical motion mechanism such as a mechanical stage, etc., and the control device 1330 can utilize a servo control system or the like. The system implementation of tracking mechanical displacement, because of the high stability and accuracy of the servo control system, can control the platform device 1300 and the camera device 1310 to achieve high-precision relative motion, thereby achieving high-precision image stitching. As an optional implementation manner, before the camera device 1310 acquires a partial image of the card, the camera device may be calibrated to extract the internal parameters and external parameters of the camera device, thereby obtaining an image between the imaging plane and the real plane. The corresponding relationship provides a reference for the subsequent image distortion correction of the system. Since the distortion of each standard partial image constituting the card image in the embodiment is corrected, the card image formed according to the standard partial image splicing has high precision, and the card image splicing system is not affected by the board. The size of the card is limited, and a larger-sized card can still obtain a higher-precision image for detection. In addition, the standard partial image obtained by the processing device 1320 after cropping the partial image can be directly spliced to form the card image according to the relative position on the card, without complicated image feature point matching analysis process, partial image clipping process and The splicing process is simpler and more efficient. Therefore, the card image splicing system proposed in this embodiment has high image splicing speed and efficiency, and is of great significance for actual industrial production.

As a specific implementation manner, the board image splicing system further includes a control device disposed on the camera device or the platform device to keep the platform device stationary, and the control device controls the camera device according to a fixed distance interval when the camera device collects a partial image. Movement relative to the platform device. In the present embodiment, the motion of the imaging device is dominant, and the advantage is that the card placed on the platform device can be prevented from randomly moving or slipping. At the same time, since the control device can achieve accurate movement, the camera device can be captured. The accuracy of the partial image.

As another specific implementation manner, the board image splicing system further includes a control device disposed on the camera device or the platform device to keep the camera device stationary, and the control device controls the platform according to a fixed distance interval when the camera device collects a partial image. The device moves relative to the camera. Since the camera device in general should try to avoid the jitter caused by the external force, so as to avoid blurring of the image, and the movement of the platform device relative to the camera device is not only technically easier to implement, for example, using a servo control system, and moving. The stability and accuracy are good, so that the control device controls the platform device to perform motion, which is more beneficial to improve the quality of the partial image captured by the camera device.

The technical features of the above-described embodiments may be arbitrarily combined. For the sake of brevity of description, all possible combinations of the technical features in the above embodiments are not described. However, as long as there is no contradiction between the combinations of these technical features, All should be considered as the scope of this manual.

The above-described embodiments are merely illustrative of several embodiments of the present invention, and the description thereof is more specific and detailed, but is not to be construed as limiting the scope of the invention. It should be noted that a number of variations and modifications may be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, the scope of the invention should be determined by the appended claims.

Claims

A card image splicing method, comprising the steps of:

Acquiring a partial image of the card acquired by the camera device, wherein the partial image is acquired by the camera device at a fixed distance interval in the same direction, and the partial images adjacent in the same direction have a coincident region;

After performing distortion correction on each of the partial images, each side of each of the partial images is separately cropped to obtain a standard partial image corresponding to each of the partial images;

The standard partial images are spliced to form a card image according to the relative positional relationship of each of the standard partial images on the card.
The board image splicing method according to claim 1, wherein

When each side of each of the partial images is cropped, the cutting width of each side is half of the width of the overlapping area corresponding to each side.
The card image splicing method according to claim 1 or 2, wherein

The trim widths of the respective sides of the partial image are the same.
The card image splicing method according to claim 1 or 2, further comprising the following steps before the step of acquiring a partial image of the card acquired by the camera device:

Obtaining an image of the marked point on the board and performing distortion correction on the image to obtain a first image;

After the position of the board is changed, acquiring an image of the marked point and performing distortion correction on the image to obtain a second image;

Obtaining an offset trajectory of the marker point according to the first image and the second image, and calculating an angle between the offset trajectory and an edge of the first image or the second image;

Adjusting a position of the imaging device or the card according to the included angle such that the offset trajectory is parallel or perpendicular to an edge of the first image or the second image.
A processing device for splicing a card image, comprising:

An acquiring unit, configured to acquire a partial image of a card acquired by the camera device, where the partial image is acquired by the camera device at a fixed distance interval in the same direction, and the partial images adjacent in the same direction have coincidence region;

a processing unit, configured to perform distortion correction on each of the partial images, for each of the partial maps Each side of the image is separately cropped to obtain a standard partial image corresponding to each of the partial images;

a splicing unit for splicing the standard partial images to form a card image according to the relative positions of the respective partial partial images.
A processing apparatus for board image stitching according to claim 5, wherein

The processing unit makes the cutting width of each side half of the width of the overlapping area corresponding to each side.
The processing device for stitching a card image according to claim 5 or 6, further comprising a point image acquiring unit, an arithmetic unit and an adjusting unit connected in sequence,

The marker point image acquisition unit is configured to acquire an image of a marker point on the card and perform distortion correction on the image to obtain a first image, and acquire an image of the marker point again after the position of the card is changed. And performing distortion correction on the image to obtain a second image;

The operation unit is configured to obtain an offset trajectory of the marker point according to the first image and the second image, and calculate the offset trajectory and an edge of the first image or the second image Angle

The adjusting unit is configured to adjust a position of the camera device or the board according to the angle, so that the offset track is parallel or perpendicular to an edge of the first image or the second image.
A card image splicing system, comprising: a platform device, an imaging device, a control device for controlling relative movement of the camera device and the platform device, and the method of any one of claims 5 to 7 a processing device for stitching a card image, the camera device being connected to the processing device,

The platform device is configured to carry a board;

The camera device is configured to collect a partial image of the card;

The control device is configured to control the camera device to acquire partial images of the card according to a fixed distance interval in the same direction, and the partial images adjacent in the same direction have overlapping regions.
The card image splicing system according to claim 8, wherein

The platform device remains stationary, and the control device controls movement of the camera device relative to the platform device in accordance with the distance interval.
The card image splicing system according to claim 8, wherein

The camera device remains stationary, and the control device controls movement of the platform device relative to the camera device according to the distance interval.