TW202126024A - An arched illumination device, an imaging system with the same and a method for imaging - Google Patents

Abstract

The present invention discloses an arched illumination device, an imaging system with the same and a method for imaging, the illumination device includes a shell with an arched structure and a plurality of LED light sources arranged on the inner side of the shell; the shell is provided with groove holes arranged along the length of the shell; the LED light sources are arranged in an array to form an LED light source array; the array includes a plurality of LED light source row units arranged along the length of the shell, and the luminous intensity and/or luminous color of each LED light source row unit could be adjusted independently. The illumination device has LED array on the inner side of an arched surface so that a measured object could be illuminated at every angle within the range of 180 degrees, and the luminous intensity and luminous color of each LED could be independently controlled to adjust an optimal light angle to cover surfaces of circuit boards with various shapes, textures and other conditions.

Description

Arch lighting device, imaging system and imaging method with the same

The invention relates to the field of circuit board detection, and in particular to an arched lighting device, an imaging system and an imaging method with the arch lighting device.

Nowadays, in the era of the highly developed electronics industry, the Printed Circuit Board (PCB) has become one of the indispensable and important components in products such as computers and electronic communications. After the PCB circuit board is completed, it needs to go through a testing process. Automated Optical Inspection (AOI) is commonly used in the industry. AOI can detect defects on the PCB, and then perform maintenance based on the defects detected by the AOI.

At present, the AOI inspection field mainly adopts the combination of CCD linear camera, zoom lens and linear light source to realize automatic optical inspection of printed circuit boards. As electronic factories introduce more and more types of circuit boards, different circuit board substrates will appear. , The shape of the circuit is different, and the color of the coating will be inconsistent. At this time, the ordinary linear light source cannot meet these conditions at the same time.

In this case, the light source plays an important role in the accuracy of the AOI inspection result, and the linear light source of the AOI in the prior art cannot meet the inspection tasks of various types of circuit boards.

In order to solve the problems of the prior art, the present invention provides an arched lighting device, an imaging system and an imaging method with the same, and optimizes the light coverage of linear camera scanning, so as to achieve the best light angle to cover various shapes and textures of scanning elements Unlike other surface conditions, the technical solution is as follows:

On the one hand, the present invention provides an arched lighting device, comprising a housing with an arched structure and a plurality of LED light sources arranged on the inner wall of the housing, and the housing is provided with the housing along the length direction of the housing. The slot through hole, the LED light sources are arranged in an array to form an LED light source array;

The LED light source array includes a plurality of LED light source array units arranged along the length direction of the housing, and the luminous intensity and/or luminous color of each LED light source array unit can be independently adjusted.

Preferably, the luminous intensity and/or luminous color of each LED light source can be independently adjusted, so that the optimal light angle can be adjusted and the flexibility is high.

Further, the slot through hole is arranged in the center of the arched structure of the housing, and the length of the slot through hole is smaller than the length of the housing, so that the light outlet is arranged in the center and the illumination is more uniform.

Optionally, the LED light sources are arranged in alignment in the arching direction of the housing, or the LED light sources are staggered arranged in the arching direction of the housing.

Further, the angle radian between adjacent LED light source column units is equal, and the LED light sources are evenly distributed, so that the uniformity of the illumination light is further improved.

In another aspect, the present invention provides an imaging system including a lens for zooming in and/or focusing, an image sensor for collecting image information, and the arched lighting device as described above, the lens being set at The image sensor is arranged above the lens of the arched surface of the housing of the arched illuminating device.

Further, the imaging system further includes a control unit for adjusting the luminous intensity and/or luminous color of the LED light source of the arch-shaped lighting device.

Further, the slot through holes on the housing of the arch-shaped lighting device have a structure of equal width, and the slot width of the slot through holes is greater than or equal to the width of the photosensitive sheet of the image sensor, which satisfies the image sensor Each time the detector is photosensitive and imaged.

Further, the light-incident side of the lens and the light-incident side of the image sensor are arranged directly opposite to the slot through hole on the housing of the arch-shaped illuminating device, so that the light from the slot through hole The light is magnifying and focusing on the incident lens, and the incident image sensor is being imaged and collected.

Further, the imaging system further includes a driving mechanism and a movable base set under the housing of the arch-shaped illuminating device. The base is used to place the target object to be imaged. Next, the base table carries the target object and moves horizontally relative to the housing of the arch-shaped lighting device. The base station can improve the smoothness of the horizontal movement of the target object. During the movement, the image sensor is used to perform line scan imaging of different parts of the target object multiple times, and finally the target is stitched by image processing. The overall imaging of the object.

Optionally, the image sensor is a CCD linear camera or CMOS.

In another aspect, the present invention provides an imaging method based on the above-mentioned imaging system, which includes the following steps:

S1. Turn on the pre-adjusted image sensor, lens, and the arched lighting device for adjusting the lighting parameters, and place the target object to be imaged under the arched lighting device;

S2. Move the target object horizontally, so that the target object moves from one side of the slot through hole on the housing of the arch-shaped lighting device to the other side;

S3. In the moving process of step S2, the image sensor images multiple times;

S4. Perform image processing on a plurality of images obtained by multiple imaging by the image sensor to obtain an image of the target object.

Preferably, each time the horizontal movement distance of the target object in step S2 is equal to the width of the photosensitive sheet of the image sensor, and each time the target object moves in step S3, the image sensor will image it once; In S4, multiple images obtained by multiple imaging of the image sensor are stitched according to the imaging time to obtain an imaging image of the target object.

Optionally, each time the horizontal movement distance of the target object in step S2 is less than or equal to the width of the photosensitive sheet of the image sensor, and each time the target object moves in step S3, the image sensor performs it once Imaging; the steps of image processing in step S4 include:

Compare the first image and the second image obtained by the image sensor twice in succession, and find the position of the edge of the first image in the second image as the stitching seam;

The first image and the second image are stitched according to the stitching seam, and the above image processing steps are repeated until all the images obtained by imaging are stitched into the image of the target object.

Further, the step of adjusting the lighting parameters of the arch-shaped lighting device includes:

Perform steps S1-S4 on the sample, and analyze each imaging parameter of the image sensor and/or the imaging image of the target object obtained by imaging. If the photosensitive flux of the image sensor is lower than The preset threshold of light flux or the brightness value and/or gray value of the local pixel block of the imaged image exceeds the preset qualification standard, then the luminous intensity and/or luminous color of the LED light source of the arch-shaped lighting device is adjusted.

Further, the pre-adjustment operation of the image sensor includes height adjustment of the image sensor, and the pre-adjustment operation of the lens includes height adjustment, magnification adjustment, and focus adjustment.

The present invention has the following beneficial effects:

a. The arched lighting device has an LED array on the inner side of the arched surface, so that the measured object can be illuminated at every angle within the range of 180°, which optimizes the light coverage of the linear camera scan;

b. The luminous intensity and color of each LED can be adjusted through software control, and the best light angle can be adjusted to cover the surface of the circuit board with various shapes, textures and other different conditions.

In the following detailed description, many specific details are set forth in order to provide a thorough explanation of the present invention. However, those skilled in the art will understand that the present invention can be practiced without these specific details. In other cases, well-known methods, procedures and components have not been described in detail so as not to obscure the present invention.

The subject matter deemed to be the present invention is specifically pointed out and clearly claimed in the concluding part of the specification. However, when referred to in conjunction with the accompanying drawings, the organization, operation method, subject, features, and advantages of the present invention can be best understood by referring to the following detailed description.

It should be understood that, for simplicity and clarity of description, the elements shown in the figures are not necessarily drawn to scale. For example, for clarity, the size of some components may be exaggerated relative to other components.

Since the illustrative embodiments of the present invention can be implemented using electronic components and circuits well known to those skilled in the art to a large extent, as described above, the details will not be explained in greater detail beyond the scope deemed necessary. , In order to understand and appreciate the basic concept of the present invention, so as not to confuse or distract the teaching of the present invention.

In one embodiment of the present invention, there is provided an arched lighting device, referring to Figures 1 to 5, the arched lighting device includes a housing 1 having an arched structure and a housing 1 arranged on the inner wall of the housing 1 A plurality of LED light sources 2, the arcuate line of the housing 1 can be a partial ellipse or a circular arc (the arc range is 150°-210°, preferably 150°-210°), the LED light source 2 Evenly distributed, the housing 1 is provided with slot through holes 11 along the length of the housing 1, the LED light sources 2 are arranged in an array to form an LED light source array (as shown in FIG. 3), and the grooves The through hole 11 is preferably arranged in the center of the arched structure of the housing 1, and the length of the slot through hole 11 is smaller than the length of the housing 1, as shown in FIG. 5.

Specifically, the LED light source array includes a plurality of LED light source array units arranged along the length direction of the housing 1, as shown in FIG. The units are evenly distributed on the inner arcuate surface of the arch-shaped lighting device, that is, the angular arcs between adjacent LED light source row units are equal (except for the two LED light source row units closest to the slot through hole 11), The luminous intensity and/or luminous color of each LED light source column unit can be adjusted independently.

The above-mentioned "the luminous intensity and/or luminous color of each LED light source column unit can be adjusted independently" means that the luminous intensity and/or luminous color can be adjusted with the LED light source column unit as an independent adjustment unit. In a more preferred embodiment of the present invention, the luminous intensity and/or luminous color of each LED light source 2 can be independently adjusted. That is to say, in this embodiment, not only a single LED light source column unit can perform light adjustment independently of other LED light source column units, different LED light sources 2 in the same LED light source column unit or in different LED light source column units The different LED light sources 2 can be adjusted individually.

In one embodiment of the present invention, the LED light source 2 is aligned in the arc direction of the housing 1, as shown in FIG. 3; in another embodiment of the present invention, the LED light source 2 is The housing 1 is staggered in the arching direction (not shown).

In one embodiment of the present invention, an imaging system is provided, see Fig. 6 and Fig. 7, including a lens 3 for magnification and/or focusing, an image sensor 4 for collecting image information, and the above implementation For the arch-shaped lighting device described in the example, the lens 3 is arranged above the arched surface of the housing 1 of the arch-shaped lighting device, the image sensor 4 is arranged above the lens 3, and the The image sensor 4 can be selected as a CCD linear camera or CMOS, and the light incident side of the lens 3 and the light incident side of the image sensor 4 are preferably the same as those on the housing 1 of the arch lighting device. The slot through hole 11 is arranged directly opposite to each other. The imaging system also includes a control unit for adjusting the luminous intensity and/or luminous color of the LED light source 2 of the arch-shaped lighting device.

As shown in FIG. 5, the slot through holes 11 on the housing 1 of the arch-shaped illuminating device are of equal width structure, and the slot width of the slot through holes 11 is greater than or equal to the width of the photosensitive film of the image sensor 4 , It satisfies the requirement of the image sensor every time for light-sensing and imaging, avoiding the phenomenon of insufficient light-sensitivity to cause part of the image to be blank.

As shown in Figures 6 and 7, the imaging system also includes a drive mechanism and a movable base 5 arranged below the housing 1 of the arched illuminating device. The base 5 is used to place the target to be imaged. Object 6, preferably, the housing 1 of the arch-shaped lighting device can be adjusted up and down according to the thickness of the target object 6, and the housing 1 of the arch-shaped lighting device does not hinder the horizontal movement of the target object 6 As mentioned earlier, the lower the height of the housing 1 of the arch-shaped lighting device, the better.

The light reflected by the LED light source 2 of the arch-shaped lighting device illuminates the target object 6 after passing through the slot hole 11 and then enters the lens 3 and finally enters the image sensor 4. Driven by the driving mechanism, the base 5 with the target object 6 moves horizontally with respect to the housing 1 of the arch-shaped lighting device. In the process of moving, the image sensor is used to perform line scan imaging of different parts of the target object multiple times. After image processing and splicing technology, the overall image acquisition of the target object 6 is finally realized, and the base station can be improved. The smoothness of the horizontal movement of the target object to improve the accuracy of imaging.

Refer to Figure 4, which shows the illuminating light path of the arched illuminating device to the target object 6 with irregular surface. The array of LED lights are installed on the inside of the arched housing 1 at equal angles, and the LED lights of different angles are emitted The light converging center coincides with the center of the arched housing 1, and is illuminated at every angle of the arc of the housing 1, to ensure that the measured object is in the center of the light source to obtain the best brightness of the light source, as shown in Figure 4 A kind of non-standard surface of the object to be measured. The schematic diagram shows that no matter what the surface of the object is to be measured, there is always a set of LED light sources in the arched lighting device that can radiate information on the surface of the object to the lens 3 and the image sensor. 4. In this way, there will be no missing detection points due to changes in the shape of the object to be detected. Secondly, due to the different substrates of printed circuit boards, which are divided into copper substrates, aluminum substrates, ceramic substrates, etc., the color of the light source lighting is very demanding. When testing objects of different colors, the color of the light source needs to be changed. , In order to enhance the contrast of the image collected in the image sensor 4 and improve the image quality. At this time, by individually controlling the RGB of each LED, and at the same time supporting the control of each LED's turn-on and brightness, in order to achieve the best The best illumination color and best illumination angle can cover the various shapes, textures and surface conditions of the scanned elements.

In an embodiment of the present invention, an imaging method based on the above-mentioned imaging system is provided. Referring to FIG. 8, the imaging method includes the following steps:

S1. Turn on the pre-adjusted image sensor, lens, and the arched lighting device for adjusting the lighting parameters, and place the target object to be imaged under the arched lighting device.

Specifically, the pre-adjustment operation of the image sensor includes height adjustment of the image sensor, and the pre-adjustment operation of the lens includes height adjustment, magnification adjustment, and focus adjustment.

Specifically, the step of adjusting the illumination parameters of the arch-shaped illumination device includes: performing steps S1-S4 on the sample, and performing each imaging parameter and/or imaging image of the sample obtained by the image sensor. Analyze, if the photosensitive flux of the image sensor is lower than the preset photosensitive flux threshold or the brightness value and/or gray value of the local pixel block of the imaged image exceeds the preset qualification standard, then the arch The LED light source of the illuminating device adjusts the luminous intensity and/or luminous color until the brightness value and gray value of the overall imaged image of the sample meet the qualification standard, or the photosensitive flux of each image of the image sensor is Meet the threshold standard.

S2. Move the target object horizontally, so that the target object moves from one side of the slot through hole on the housing of the arch-shaped lighting device to the other side.

S3. In the moving process of step S2, the image sensor images multiple times.

S4. Perform image processing on a plurality of images obtained by multiple imaging by the image sensor to obtain an image of the target object.

Specifically, in one embodiment, as shown in FIG. 9, each time the horizontal movement distance of the target object in step S2 is equal to the width of the photosensitive sheet of the image sensor, and each time the target object moves in step S3, the The image sensor images it once; in step S4, multiple images obtained by the image sensor multiple times are spliced according to the imaging time to obtain the imaged image of the target object.

In another embodiment, each time the horizontal movement distance of the target object in step S2 is less than or equal to the width of the photosensitive sheet of the image sensor, and each time the target object moves in step S3, the image sensor pairs It performs one imaging; because the distance of each horizontal movement is less than the width of the photosensitive film, there is an overlap in the front and back imaging. This overlapped part needs to be removed before image stitching, as shown in Figure 10, step S4 The steps of image processing include:

Compare the first image and the second image obtained by the image sensor twice in succession, and find the position of the edge of the first image in the second image as the stitching seam;

The first image and the second image are stitched according to the stitching seam, and the above image processing steps are repeated until all the images obtained by imaging are stitched into the image of the target object.

In addition, those skilled in the art will realize that the boundaries between the above operations are only exemplary. Multiple operations can be combined into a single operation, a single operation can be distributed in additional operations, and operations can be performed at least partially overlapping times. In addition, alternative embodiments may include multiple illustrations of specific operations, and the order of operations may be changed in various other embodiments.

However, other modifications, changes and substitutions are also possible. Therefore, the description and drawings should be viewed in an exemplary rather than restrictive sense.

In the scope of the patent application, any reference signs placed between parentheses shall not be regarded as restrictive claims. The word "comprising" does not exclude the existence of other elements or steps listed in the scope of the patent application. In addition, the term "a" or "an" as used herein is defined as one or more than one. Moreover, the use of introductory phrases such as "at least one" and "one or more" in the scope of the patent application should not be construed as implying that the indefinite article "a" or "an" introducing another element of the scope of the patent application will include such introduction. The scope of any particular application for patents is limited to inventions that contain only one such element, even if the scope of the same patent application includes the introductory phrase "one or more" or "at least one" and indefinite articles such as "one" or "One". The same is true for the use of definite articles. Unless otherwise stated, terms such as "first" and "second" are used to arbitrarily distinguish the elements described by these terms. Therefore, these terms are not necessarily intended to indicate the timing or other order of priority of these elements. The mere fact that certain measures are described in mutually different patent applications does not mean that the combination of these measures cannot be used.

Although certain features of the present invention have been illustrated and described herein, those of ordinary skill in the art will now think of many modifications, substitutions, changes and equivalents. Therefore, it should be understood that the scope of the attached patent application is intended to cover all these modifications and changes that fall within the true spirit of the present invention.

1: shell 2: LED light source 3: lens 4: Image sensor 5: Abutment 6: target object 11: Slot through hole

The subject matter deemed to be the present invention is specifically pointed out and clearly claimed in the concluding part of the specification. However, when referenced in conjunction with the accompanying drawings, the organization, operating methods, as well as themes, features and advantages of the present invention can be best understood by referring to the following detailed description, in which: Fig. 1 is a schematic structural diagram of an arch-shaped lighting device provided by an embodiment of the present invention; Figure 2 is a partial enlarged detail view of Figure 1; Figure 3 is an internal side view of an arched lighting device provided by an embodiment of the present invention; 4 is a cross-sectional view in the width direction of the arch-shaped lighting device provided by an embodiment of the present invention; Figure 5 is a top view of an arched lighting device provided by an embodiment of the present invention; 6 is a schematic diagram of the first state of the imaging system provided by the embodiment of the present invention; 7 is a schematic diagram of the second state of the imaging system provided by the embodiment of the present invention; FIG. 8 is a flowchart of an imaging method provided by an embodiment of the present invention; Figure 9 is a flowchart of the first image processing method provided by an embodiment of the present invention; FIG. 10 is a flowchart of a second image processing method provided by an embodiment of the present invention.

1: shell

2: LED light source

11: Slot through hole

Claims (16)

An arched lighting device, which is characterized in that it comprises a housing with an arched structure and a plurality of LED light sources arranged on the inner wall of the housing, and the housing is provided with grooves arranged along the length of the housing. Holes, the LED light sources are arranged in an array to form an LED light source array; The LED light source array includes a plurality of LED light source array units arranged along the length direction of the housing, and the luminous intensity and/or luminous color of each LED light source array unit can be independently adjusted. The arch-shaped lighting device according to claim 1, characterized in that the luminous intensity and/or luminous color of each LED light source can be independently adjusted. The arch-shaped lighting device according to claim 1, wherein the slot through hole is provided in the center of the arch structure of the housing, and the length of the slot through hole is less than the length of the housing. The arched lighting device according to claim 1, wherein the LED light sources are aligned in the arch direction of the housing, or the LED light sources are staggered in the arch direction of the housing set up. The arch-shaped lighting device according to claim 1, wherein the angle radian between adjacent LED light source column units is equal, and the LED light sources are evenly distributed. An imaging system, characterized by comprising a lens for zooming in and/or focusing, an image sensor for collecting image information, and the arched lighting device according to any one of claims 1-5, The lens is arranged above the arch surface of the housing of the arch-shaped illuminating device, and the image sensor is arranged above the lens. The imaging system according to claim 6, further comprising a control unit for adjusting the luminous intensity and/or luminous color of the LED light source of the arch-shaped lighting device. The imaging system according to claim 6, wherein the slot through hole on the housing of the arch-shaped illuminating device has a structure of equal width, and the slot width of the slot through hole is greater than or equal to the image sensor The width of the photosensitive film of the device. The imaging system according to claim 6, wherein the light incident side of the lens and the light incident side of the image sensor are both arranged directly opposite to the slot through hole on the housing of the arch-shaped illuminating device . The imaging system according to claim 6, characterized in that it further comprises a driving mechanism and a movable base provided under the housing of the arch-shaped illuminating device, the base is used to place the target object to be imaged, Driven by the driving mechanism, the base with the target object moves horizontally with respect to the housing of the arch-shaped lighting device. The imaging system according to claim 6, wherein the image sensor is a CCD linear camera or a CMOS. An imaging method based on the imaging system according to any one of Claims 6-11, characterized in that it comprises the following steps: S1. Turn on the pre-adjusted image sensor, lens, and the arched lighting device for adjusting the lighting parameters, and place the target object to be imaged under the arched lighting device; S2. Move the target object horizontally, so that the target object moves from one side of the slot through hole on the housing of the arch-shaped lighting device to the other side; S3. In the moving process of step S2, the image sensor images multiple times; S4. Perform image processing on a plurality of images obtained by multiple imaging by the image sensor to obtain an image of the target object. The imaging method according to claim 12, characterized in that, each time the horizontal movement distance of the target object in step S2 is equal to the width of the photosensitive sheet of the image sensor, and each time the target object moves in step S3, the image The image sensor images it once; in step S4, multiple images obtained by the image sensor multiple times are spliced according to the imaging time to obtain the imaged image of the target object. The imaging method according to claim 12, characterized in that each time the horizontal movement distance of the target object in step S2 is less than or equal to the width of the photosensitive sheet of the image sensor, and each time the target object moves in step S3, the The image sensor performs an imaging on it; the steps of image processing in step S4 include: Compare the first image and the second image obtained by the image sensor twice in succession, and find the position of the edge of the first image in the second image as the stitching seam; The first image and the second image are stitched according to the stitching seam, and the above image processing steps are repeated until all the images obtained by imaging are stitched into the image of the target object. The imaging method according to claim 12, wherein the step of adjusting the lighting parameters of the arch-shaped lighting device includes: Perform steps S1-S4 on the sample, and analyze each imaging parameter of the image sensor and/or the imaging image of the target object obtained by imaging. If the photosensitive flux of the image sensor is lower than The preset threshold of light flux or the brightness value and/or gray value of the local pixel block of the imaged image exceeds the preset qualification standard, then the luminous intensity and/or luminous color of the LED light source of the arch-shaped lighting device is adjusted. The imaging method according to claim 12, wherein the pre-adjustment operation of the image sensor includes height adjustment of the image sensor, and the pre-adjustment operation of the lens includes height adjustment, magnification adjustment, and Focus magnification adjustment.

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