A capturing device and a capturing method for defect shadow images of a transparent board

Abstract

The application discloses a kind of capturing device and capturing method of transparent board defect shadow image, capturing device is installed in the conveying system for transparent board, capturing device includes: acquisition device, point light source system, curtain, controller;Point light source system and curtain are provided with transparent board to be obtained shadow image between, point light source system and acquisition device are located in the same side of the transparent board to be obtained shadow image, acquisition device is connected with the controller communication;Acquisition device includes multiple area array camera, the field of view of all area array camera covers the width of the transparent board to be obtained shadow image, controller is used to control the exposure timing of acquisition device according to the parameter information of transparent board, and any adjacent area array camera is not exposed simultaneously.The method provided by the application controls the timing of exposure through program, ensures that any two adjacent cameras are at least spaced apart the exposure time required by camera to take a photo to obtain clear defect shadow image.

Description

Technical Field

[0001] This invention relates to the field of image technology, and specifically to a device and method for capturing shadow images of defects in transparent sheet materials. Background Technology

[0002] With the continuous development of my country's economy and the continuous improvement of people's living standards, transparent sheets such as glass are widely used in industries such as construction, furniture, home appliances, and automobiles. Therefore, it is necessary to detect micro-defects (e.g., 0.08mm) in transparent sheets. In reality, a shadow is a dark area formed when an object blocks the propagation of light, preventing it from passing through an opaque object. It consists of the umbra and penumbra. The umbra is the shadow formed when the light emitted by a luminous body is completely blocked by a non-transparent object, while the penumbra is a shadow formed by partial obstruction, also known as a blurred shadow. With the light source and object shape remaining constant, the farther the object is from the light source, the smaller the penumbra and the clearer the shadow; conversely, the closer the object is to the light source, the larger the penumbra and the blurrier the shadow.

[0003] For industrial area scan cameras, if a clear image of a moving object is required, the smaller the object, the shorter the exposure time is needed; the faster the speed, the shorter the exposure time is also needed. Otherwise, a trailing phenomenon will occur, and a clear image cannot be formed.

[0004] In practical applications, the transparent panels to be inspected are often quite large, sometimes even requiring the inspection of a single giant panel measuring 3.66 meters wide and 18 meters long. Conventional techniques would require arranging multiple industrial area scan cameras along the width of the panel, taking a series of photos at regular intervals along the panel's movement direction, and then processing all the photos to stitch them together into a computer-readable image.

[0005] When photographing actual objects, a strip-shaped surface light source with sufficient intensity is required to obtain a clear image. However, when photographing the shadows of minute defects, using a strip-shaped surface light source will result in a lack of a clear shadow, or even an invisible shadow, because the penumbra area formed by the point defect is much larger than the umbra area. If a single point light source with a small luminous area is used, then all cameras across the entire width of the board will not have sufficient light intensity to form an image suitable for computer processing. If each camera is equipped with only one light source, the point defect will create multiple interfering shadows, and the acquired images cannot be used for image processing. Therefore, how to obtain clear images of defect shadows is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] Therefore, the present invention provides a device and method for capturing shadow images of defects in transparent sheet materials, which overcomes the shortcomings of the prior art in that it cannot obtain clear shadow images of defects in transparent sheet materials.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] In a first aspect, embodiments of the present invention provide a device for capturing shadow images of defects in transparent sheet materials. The capturing device is installed in a conveying system for transparent sheet materials, the conveying system including at least one processing station and one or more conveyors for conveying the transparent sheet material from one station to another during processing. The capturing device includes: an acquisition device, a point light source system, a screen, and a controller.

[0009] A transparent plate for acquiring shadow images is disposed between the point light source system and the screen. The point light source system and the acquisition device are located on the same side of the transparent plate for acquiring shadow images. The acquisition device is communicatively connected to the controller.

[0010] The acquisition device includes multiple area scan cameras, the field of view of all the area scan cameras covers the entire width of the transparent plate to be acquired shadow image, and the controller is used to control the exposure sequence of the acquisition device according to the parameter information of the transparent plate. Any adjacent area scan cameras are not exposed at the same time. The parameter information includes: the moving speed, position and thickness of the transparent plate.

[0011] In one embodiment, when the point light source system and the acquisition device are located on the same side of the transparent plate to which the shadow image is to be acquired, the screen is an opaque screen; when the point light source system and the acquisition device are located on opposite sides of the transparent plate to which the shadow image is to be acquired, the screen is a semi-transparent screen.

[0012] In one embodiment, the point light source system is composed of multiple point light sources, which are turned on and off according to a preset lighting pattern.

[0013] In one embodiment, the plurality of point light sources are spaced apart by a preset distance.

[0014] In one embodiment, the number and spatial distribution of the acquisition devices vary according to different needs, with each area array camera combined with a preset number of point light sources.

[0015] In one embodiment, each area array camera activates its associated point light source before exposure and deactivates it after exposure.

[0016] In one embodiment, after all the area scan cameras have been exposed, the transparent plate is transferred from the current station to the next station, and subsequent acquisition of the transparent plate shadow image continues.

[0017] Secondly, embodiments of the present invention provide a method for capturing shadow images of defects in transparent sheet materials, based on the device for capturing shadow images of defects in transparent sheet materials according to the first aspect, the capturing method comprising:

[0018] Step 1: When the transparent sheet is in the current processing station, the point light source starts working according to the preset lighting mode;

[0019] Step 2: Before exposure, the point light source combined with the acquisition device starts to emit light, and after exposure, the point light source combined with it is turned off;

[0020] Step 3: After all the area array cameras in the acquisition device have been exposed, the shadow image of the target area of ​​the transparent plate at the current processing station is obtained;

[0021] Step 4: The transparent sheet is transferred from the current processing station to the next processing station, and then proceeds to Step 1.

[0022] In one embodiment, the preset lighting mode includes: the point light source combined with the area scan camera starts to emit light before the area scan camera is exposed, and the point light source combined with the area scan camera is turned off after the exposure is completed. Based on the fact that adjacent area scan cameras cannot be exposed at the same time, the two combined light sources of adjacent area scan cameras cannot emit light at the same time during the camera exposure.

[0023] In one embodiment, the preset lighting mode further includes: controlling the point light source to turn on and off at different times and in different spaces, and the plurality of area array cameras respectively capturing the shadow image of the transparent plate when the point light source in combination with them emits light.

[0024] The technical solution of this invention has the following advantages:

[0025] 1. This invention discloses a device and method for capturing shadow images of defects in transparent sheet materials. The field of view of all area array cameras covers the entire width of the transparent sheet material whose shadow image is to be acquired. The number of cameras can be increased or decreased according to the width of the transparent sheet material, so that the width of the transparent sheet material to be detected can be arbitrarily selected.

[0026] 2. This invention discloses a device and method for capturing shadow images of defects in transparent sheet materials. Since two adjacent cameras cannot be exposed and photographed simultaneously, the light sources of adjacent cameras will not form interfering shadows in the camera area. The defect images obtained at this time are beneficial for computer processing.

[0027] 3. This invention discloses a device and method for capturing shadow images of defects in transparent sheet materials. Because the camera exposure time is very short and the light source illumination time is shortened, the heat generated is also very little. Compared with the constant light mode, the heat dissipation measures are relatively less and the power consumption is also less. Attached Figure Description

[0028] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0029] Figure 1 This is a front view of a device for capturing shadow images of defects in transparent sheet metal, provided in an embodiment of the present invention.

[0030] Figure 2 This is a top view of a device for capturing shadow images of defects in transparent sheet metal, provided in an embodiment of the present invention.

[0031] Figure 3 This is a flowchart illustrating a specific example of a method for capturing shadow images of defects in transparent sheet materials, as provided in an embodiment of the present invention. Detailed Implementation

[0032] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0034] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can also refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0035] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0036] Example 1

[0037] This invention provides an apparatus for capturing shadow images of defects in transparent sheet materials. The capturing apparatus is installed in a conveying system for transparent sheet materials. The conveying system includes at least one processing station and one or more conveyors for transferring the transparent sheet material from one station to another during processing. This invention uses a large glass plate as an example of a transparent sheet material; the size of the sheet material is not limited here and can be selected according to actual conditions.

[0038] In embodiments of the present invention, such as Figure 1 As shown, the capture device includes: a data acquisition unit, a point light source system, a screen, and a controller. The data acquisition unit is communicatively connected to the controller. A transparent panel with the shadow image to be acquired is placed between the point light source system and the screen. The data acquisition unit includes multiple area scan cameras. The field of view of all area scan cameras covers the entire width of the transparent panel with the shadow image to be acquired. There is a slight overlap in the imaging areas between the cameras, and the imaging width of all cameras exceeds the maximum width of the transparent panel. Each area scan camera has an independent light source system. Cameras can be added or removed according to the width of the transparent panel, so that the width of the transparent panel to be detected can be arbitrarily selected without being limited by the panel width.

[0039] The controller is used to control the exposure sequence of the acquisition device based on the parameter information of the transparent sheet. No two adjacent area array cameras can be exposed simultaneously. This ensures that the point light sources of adjacent cameras will not create interfering shadows in their respective camera areas. The acquired defect shadow images are beneficial for computer image processing to avoid interference. The parameter information includes: the moving speed, position, and thickness of the transparent sheet.

[0040] In practical applications, when the point light source system and the acquisition device can be located on the same side or opposite side of the transparent plate on which the shadow image is to be acquired, Figure 1 Using the example of being on the same side, when the point light source system and the acquisition device are on the same side of the transparent panel from which the shadow image is to be acquired, the screen is opaque, such as a white diffuse reflective screen. When the point light source system and the acquisition device are on opposite sides of the transparent panel from which the shadow image is to be acquired, the screen is semi-transparent so that the shadow can be captured from the back of the screen. The choice between opaque and semi-transparent screens is not limited here; the appropriate choice should be made based on the actual situation.

[0041] In this embodiment of the invention, the field of view of all area array cameras covers the entire width of the transparent plate to which the shadow image is to be acquired. Cameras can be added or removed according to the width of the transparent plate, so that the width of the transparent plate to be detected can be arbitrarily selected.

[0042] In this embodiment of the invention, the point light source system is composed of multiple point light sources. These point light sources are switched on and off according to a preset lighting pattern. The multiple point light sources are spaced apart by a preset distance. They are arranged in different spatial configurations; this is merely an example and not a limitation. In practice, the appropriate preset distance should be selected based on the actual situation. Since the camera light source is only responsible for illuminating a single camera, and the illuminated area is relatively small, the required light intensity is also relatively small. Therefore, a point light source with a small luminous area is selected. The smaller the luminous area of ​​the light source, the smaller the penumbra formed by the point defect, and the clearer the shadow image.

[0043] In this embodiment of the invention, the number and spatial distribution of the acquisition devices vary according to different needs, with each area scan camera combined with a preset number of point light sources. The number of point light sources combined with each area scan camera is not limited here; it is selected according to the actual situation. One or more point light sources will form corresponding shadow images. These shadow images have obvious and regular characteristics, which is beneficial for computer processing of images to match defect features. Before each area scan camera is exposed, the point light sources combined with it start emitting light; after exposure, the point light sources combined with it turn off. Because the camera's exposure time is very short, the illumination time of the point light sources is also shortened, and the heat generated is reduced. Compared to the constant-on mode, fewer heat dissipation measures are taken, and less electrical energy is consumed.

[0044] In one specific embodiment, such as Figure 2 The image shown is a top view of a device for capturing shadow images of defects in transparent panels. Each area array camera is equipped with a preset number of point light sources. The spatial and positional information of the point light sources is not limited here; this is just an example.

[0045] In this embodiment of the invention, after all the area scan cameras have been exposed, the transparent plate is transferred from the current station to the next station, and subsequent acquisition of the transparent plate shadow image continues.

[0046] In one specific embodiment, in order to acquire an image of the entire glass panel, the controller controls the exposure of the area array camera based on parameters such as the glass's moving speed, position, and thickness. A preferred exposure sequence is that when the glass moves to the camera position, it is divided into two groups according to the odd and even numbers of the camera numbers. The two groups of cameras are exposed sequentially, and the time interval between exposures is greater than the camera exposure time. After all cameras have been exposed once, another round of exposure is started after a certain time interval, until the glass panel leaves the camera's imaging area.

[0047] When the cameras are spaced close together, another exposure sequence is to divide them into three groups according to their camera numbers (1#4#7#..., 2#5#8#..., 3#6#9#...) as the glass moves to the camera position. These groups are then exposed sequentially at intervals. After all cameras have completed one exposure cycle, another cycle of exposures is initiated at intervals until the glass plate leaves the camera's imaging area. The camera exposure sequence is again not restricted and can be adjusted according to the actual situation.

[0048] The transparent sheet defect shadow image capture device provided in this embodiment of the invention uses one or more bright spot light sources as exposure light sources for each area array camera. The exposure timing is controlled by a program to ensure that any two adjacent cameras take pictures at least once the required exposure time, thereby obtaining a clear shadow image.

[0049] Example 2

[0050] This invention provides a method for capturing shadow images of defects in transparent sheet materials, such as... Figure 3 As shown, the device for capturing shadow images of defects in transparent sheet metal based on Embodiment 1 includes a capture method comprising:

[0051] Step 1: When the transparent sheet is in the current processing station, the point light source starts working according to the preset lighting mode.

[0052] Step 2: Before exposure, the point light source combined with the acquisition device starts to emit light, and after exposure, the point light source combined with it is turned off.

[0053] Step 3: After all the area array cameras in the acquisition device have been exposed, the shadow image of the target area of ​​the transparent plate of the current processing station is obtained.

[0054] Step 4: The transparent sheet is transferred from the current processing station to the next processing station, and then proceeds to Step 1.

[0055] In this embodiment of the invention, the preset illumination mode includes: the point light source combined with the area scan camera starts emitting light before exposure and turns off after exposure. Since adjacent area scan cameras cannot be exposed simultaneously, the exposure time interval can be set to be longer than the camera exposure time. The two combined light sources of adjacent area scan cameras cannot emit light simultaneously during the exposure period of adjacent cameras. The point light sources are controlled to illuminate and turn off at different times and in different spaces, and multiple area scan cameras acquire shadow images of the transparent sheet material when the point light sources they are combined with are emitting light.

[0056] In this embodiment of the invention, the preset lighting mode can be set in advance according to the camera's exposure sequence, or the point light source system can be connected to a controller for control. The connection method of the point light source system is not limited here; it can be connected according to the actual situation.

[0057] The method for capturing shadow images of defects in transparent sheet materials provided in this embodiment of the invention is not limited in the width of the sheet material to be captured. Since the camera exposure time is very short and the light source illumination time is shortened, the heat generated is also very little. Compared with the constant light mode, the heat dissipation measures are relatively less and the power consumption is also less.

[0058] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A device for capturing shadow images of defects in transparent sheet materials, said capturing device being installed in a conveying system for transparent sheet materials, said conveying system comprising at least one processing station and one or more conveyors for conveying the transparent sheet material from one station to another during processing, characterized in that, The capture device includes: a data acquisition device, a point light source system, a screen, and a controller; A transparent plate for acquiring shadow images is disposed between the point light source system and the screen. When the point light source system and the acquisition device are located on the same side of the transparent plate for acquiring shadow images, the screen is opaque; when the point light source system and the acquisition device are located on opposite sides of the transparent plate for acquiring shadow images, the screen is semi-transparent. The acquisition device is communicatively connected to the controller. The point light source system is composed of multiple point light sources, which are turned on and off according to a preset lighting mode. The multiple point light sources are spaced at a preset distance. The number and spatial distribution of the acquisition devices vary according to different needs. Each area scan camera is combined with a preset number of point light sources. Before each area scan camera is exposed, the point light sources combined with it start to emit light, and after the exposure is completed, the point light sources combined with it turn off. The acquisition device includes multiple area array cameras, the field of view of all the area array cameras covering the entire width of the transparent plate to be acquired for the shadow image. The controller is used to control the exposure sequence of the acquisition device according to the parameter information of the transparent plate, and any adjacent area array cameras are not exposed at the same time. The parameter information includes: the moving speed, position and thickness of the transparent plate. Controlling the exposure sequence of the acquisition device according to the parameter information of the transparent plate, and any adjacent area array cameras are not exposed at the same time, includes: dividing the cameras into two groups according to the odd and even numbers of the camera numbers, and exposing the two groups of cameras sequentially, with the exposure time interval being greater than the camera exposure time; or, dividing the cameras into three groups according to the camera numbers, and exposing the three groups of cameras sequentially, with the exposure time interval being greater than the camera exposure time.

2. The device for capturing shadow images of defects in transparent sheet metal according to claim 1, characterized in that, Once all the area scan cameras have been exposed, the transparent panel is transferred from the current station to the next station, and subsequent acquisition of the transparent panel's shadow image continues.

3. A method for capturing shadow images of defects in transparent sheet materials, characterized in that, Based on the device for capturing shadow images of defects in transparent sheet metal according to any one of claims 1-2, the capturing method includes: Step 1: When the transparent sheet is in the current processing station, the point light source starts working according to the preset lighting mode; Step 2: Before exposure, the point light source combined with the acquisition device starts to emit light, and after exposure, the point light source combined with it is turned off; Step 3: After all the area array cameras in the acquisition device have been exposed, the shadow image of the target area of ​​the transparent plate at the current processing station is obtained; Step 4: The transparent sheet is transferred from the current processing station to the next processing station, and then proceeds to Step 1.

4. The method for capturing shadow images of defects in transparent sheet metal according to claim 3, characterized in that, The preset lighting mode includes: the point light source combined with the area scan camera starts to emit light before the area scan camera is exposed, and the point light source combined with the area scan camera is turned off after the exposure is completed. Based on the premise that adjacent area scan cameras cannot be exposed at the same time, the combined light source of adjacent area scan cameras cannot emit light at the same time during the camera exposure.

5. The method for capturing shadow images of defects in transparent sheet metal according to claim 4, characterized in that, The preset lighting mode also includes: controlling the point light source to turn on and off at different times and in different spaces, and the multiple area array cameras to capture the shadow image of the transparent plate when the point light source they are combined with emits light.

Images