TW201530121A - Panel defective pixel detection method and system - Google Patents

Abstract

A panel defective pixel detection method, applicable to detecting defective pixels of a panel, includes the following steps: capturing a transmission image representing a position where defective pixels and foreign matters situate by an image capturing module; capturing a reflection image by the image capturing module, wherein a position of higher brightness in the reflection image are generated as lights reflected by the foreign matters on a surface of the panel are captured through a polarizer, and the reflected lights are linearly polarized lights along a first direction when there are no foreign matters in the surface of the panel and the polarizer has an optical axis perpendicular to the first direction so as to block the linearly polarized lights; performing image subtraction, by a processing module, by subtracting pixel values of the reflection image from the pixel values of the transmission image to form a resulting image where the positions with higher brightness in the resulting image stands for the positions of the defective pixels.

Description

Panel bright spot detection method and system

The invention relates to a detection method, in particular to a panel bright point detection method and system.

There is a panel bright spot detection technology for detecting light by using image recognition mode; that is, light is taken from one side of one panel and image is captured on the other side. If there is an internal defect in the panel that causes a bright spot, the internal defect cannot block the passage of light, and the other normal part blocks the light, the brightness of the corresponding defect in the captured image is higher than the surrounding area, thereby detecting The panel is highlighted.

However, in the prior art, when there is foreign matter such as particles or dust on the surface of the panel, if light penetrates the panel, the foreign matter may reflect the light, and the image captured may correspond to the brightness of the foreign object being higher than the surrounding area, thereby causing Misjudgment. In this case, the inspector cannot distinguish which bright spots in the image are caused by bright spots, and which bright parts are caused by foreign matter on the surface.

Therefore, the object of the present invention is to provide a distinguishable image A method of detecting a bright spot of a panel in a bright place due to the presence of foreign matter on the surface.

Accordingly, it is another object of the present invention to provide a panel highlight detection system that is capable of distinguishing bright areas due to the presence of foreign matter on a surface in an image.

Therefore, the panel bright spot detecting method of the present invention is implemented by a panel bright spot detecting system and is suitable for detecting a panel. The system comprises an image capturing module, a processing module, a light source module, and a polarization having an optical axis. The method includes the following steps: the image capturing module captures a transmitted image, and the transmitted image is formed by the image capturing module after the light emitted by the light source module is penetrated by the image capturing module.

The image capturing module captures a reflected image, and the reflected image is captured by the image capturing module when the light emitted by the light source module is reflected to form a reflected light, and the reflected light passes through the polarizing lens. Forming, the reflected light is linearly polarized light polarized in a first direction when there is no foreign matter on the surface of the panel, and the optical axis of the polarizer is perpendicular to the first direction, and the reflected light has foreign matter on the surface of the panel. In the case of foreign matter reflection, it is an unpolarized light that partially passes through the polarizer.

The processing module performs image subtraction, and subtracts each pixel value of the reflected image from each pixel value of the transmitted image to form a resultant image.

Preferably, the method further includes: performing the following steps before capturing the reflected image: erecting the light source module, the polarizer, and the image capturing module, so that the light emitted by the light source module is incident on the panel at a Brewster angle. And phase The same angle reflection also causes the polarizer and the image capturing module to be sequentially located on the path of the reflected light, and the optical axis of the polarizer is perpendicular to the first direction, and the image capturing module is taken toward the light reflecting portion. Like, the reflected light passing through the polarizer is captured.

Preferably, the image capturing module is imaged by line scanning.

Preferably, the processing module further determines, by using the image processing method, the position of the pixel whose brightness is higher than four weeks or whose brightness value exceeds a threshold value.

Therefore, the panel bright spot detecting system of the present invention is suitable for detecting a panel, comprising: a transmitting light source and a first image capturing unit on opposite sides of the panel, the light emitted by the transmitting light source is penetrated by the panel The first image capturing unit captures a transmission image.

a reflective light source located on the same side of the panel, a second image capturing unit, and a polarizer disposed before the second image capturing unit and having an optical axis, and the light emitted by the reflected light source is incident at a Brewster angle. And reflecting at a same angle to form a reflected light, wherein the polarizer and the second image capturing unit are sequentially located on the path of the reflected light, and the second image capturing unit takes an image toward the light reflecting portion, and the image is taken through the polarization The reflected light of the mirror forms a reflected image, and the reflected light is linearly polarized light polarized in a first direction when there is no foreign matter on the surface of the panel, and the optical axis of the polarizer is perpendicular to the first direction, and the reflected light is reflected In the case where there is a foreign matter on the surface of the panel and is reflected by the foreign matter, it is an unpolarized light that partially passes through the polarizer.

The processing module performs image subtraction, and subtracts each pixel value of the reflected image from each pixel value of the transmitted image to form a resultant image.

Preferably, the first image capturing unit and the second image capturing unit are respectively a line scan camera.

Preferably, the processing module determines, by using the image processing method, the position of the pixel whose brightness is higher than four weeks or whose brightness value exceeds a threshold value.

The effect of the invention is that by capturing the transmitted image and the reflected image, and by subtracting the image, the position of the bright spot defect can be obtained more accurately, and the probability of false detection is reduced, so the object of the invention can be achieved.

1‧‧‧ Panel Highlight Detection System

11‧‧‧Image capture module

111‧‧‧First image capture unit

112‧‧‧Second image taking unit

12‧‧‧Processing module

13‧‧‧Light source module

131‧‧‧transmitted light source

132‧‧‧Reflective light source

14‧‧‧Polarizer

2‧‧‧ panel

21‧‧‧ Highlight defects

22‧‧‧ Foreign objects

3‧‧‧ Vehicles

N1‧‧‧air refractive index

N2‧‧‧ panel refractive index

θ _B ‧‧‧ Brewster Point

S1-S2, S20‧‧‧ steps

The other features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments of the invention, wherein: FIG. 2 is a flow chart illustrating a preferred embodiment of the method for detecting a bright spot of the panel of the present invention; FIG. 3 is a partial schematic view of the system for illustrating the transmission image; FIG. 4 is a schematic view of the image. The image captured in the transmission mode of the embodiment; FIG. 5 is a partial schematic view of the system, illustrating the preferred embodiment capturing the reflected image; 6 is a partial schematic view of a system for illustrating a reflected image in the case of a foreign object; FIG. 7 is a schematic view showing an image of a foreign object captured by the preferred embodiment in the reflective mode; FIG. 8 is a schematic diagram showing the result of image processing in the preferred embodiment.

Referring to FIG. 1, a preferred embodiment of the method for detecting a bright spot of a panel of the present invention is performed by a panel bright spot detecting system 1 and is suitable for detecting a panel 2. The panel spot detection system 1 includes a camera module 11 and a processing module 12 , a light source module 13 , and a polarizer 14 . The light source module 13 includes a transmission light source 131 and a reflection light source 132. The image capturing module 11 includes a first image capturing unit 111 that cooperates with the light source 131 and a second image capturing unit 112 that cooperates with the light source 132. The first image capturing unit 111 and the second image capturing unit 112 are respectively line scan cameras having a photosensitive coupling element and a lens, and all are taken by line scanning. The polarizer 14 is disposed before the second image capturing unit 112. The panel 2 is placed on a carrier 3 such as a conveyor belt, but the carrier 3 is reserved with a portion (not shown) through which light can pass. Referring to Figures 2 and 3, the method includes the following steps: Step S1 - The first image capturing unit 111 captures a transmission image. The positions of the transmission light source 131, the panel 2, and the first image capturing unit 111 are substantially in line. The transmitted light source 131 and the first image capturing unit 111 are located on opposite sides of the panel 2, so that the light emitted by the transmitted light source 131 is penetrated. The panel 2 is then captured by the first image capturing unit 111.

The panel 2 desirably blocks the passage of light, but as described in the prior art, if the captured image is partially bright, it may be caused by a bright spot defect 21 or a foreign object 22. For example, the image obtained in this step is shown in FIG. 4, and there are three groups of bright pixels P11, P12, and P13 in the image, and each group of bright pixels represents (usually multiple) adjacent brightness is higher than four weeks. A pixel, or a pixel whose brightness exceeds a threshold. Referring to FIGS. 2 and 5, steps S20 and S2 are described below. It should be noted that steps S1 and S2 do not need to be performed in a specific order, as long as both are performed, then step S3 is performed, and step S20 is only required. It can be executed before step S2.

Step S20 - erecting the reflected light source 132 and the second image capturing unit 112. The reflective light source 132 and the second image capturing unit 112 are located on the same side of the panel 2, and the reflected light source 132 is disposed such that the emitted light is incident on the panel 2 at a Brewster's angle θ _B and is reflected at the same angle θ _B And the second image capturing unit 112 is located on the path of the reflected light, and takes an image toward the light reflection surface, thereby capturing the reflected light, wherein In the present embodiment, n1 refers to the refractive index of air, and n2 refers to the refractive index of the outermost layer of the panel 2, which may be glass or polarizer. Since the polarizer 14 is disposed before the second image capturing unit 112, the reflected light must pass through the polarizer 14 before entering the second image capturing unit 112.

The incident light emitted by the reflective light source 132 is unpolarized, but is reflected by the Brewster angle to be converted into linearly polarized light polarized in a first direction, and the polarizer 14 disposed before the second image capturing unit 112 has An optical axis, and the step is further arranged such that the optical axis of the polarizer 14 is perpendicular to the first direction.

In this embodiment, two light sources and two image capturing units are used, but not limited thereto, or only one light source and one image capturing unit may be used, and the light source and the image capturing are adjusted when different steps are performed. The position and angle of the unit can be to the desired position and angle.

Step S2 - The second image capturing unit 112 captures a reflected image. In the case where the image taken by the second image capturing unit 112 has no foreign matter, the incident light is converted into linearly polarized light polarized in the first direction after being reflected, and then the optical axis is perpendicular to the polarization in the first direction. The mirror 14 is filtered out, so that the image taken by the second image capturing unit 112 has a low brightness.

Referring to FIG. 6, when the foreign object 22 appears at the position taken by the second image capturing unit 112, since the incident light is reflected by the foreign object 22 in different directions, the reflected light is not converted into linearly polarized light, but is Unpolarized light, so that the unpolarized light will become light polarized along the optical axis after passing through the polarizer 14, in other words, a bright pixel P21 of FIG. 7 will be generated, representing the position of the foreign object 22. Referring now to Figure 2, steps S3, S4 are illustrated.

Step S3: The processing module 12 performs image subtraction to obtain a result image as shown in FIG. Image subtraction refers to subtracting the pixel values of the pixels of the two images, and the obtained values form another image. In this step, the pixel value of the transmitted image is subtracted from the pixel value of the reflected image to obtain the pixel value of the resulting image. If in some cases the reflected image has a bright pixel but the transmitted image does not, so that the result of the subtraction is negative, the pixel value of the resulting image is defined as zero. For example, the transmitted image has bright pixels P11, P12, and P13 as shown in FIG. 4, and the reflected image has a bright color as shown in FIG. Pixel P21, and P21 and P12 are in the same position, so the bright pixels will disappear after the image is subtracted, and the bright pixels P31 and P32 in Fig. 8 are left. However, the foregoing is only an example, and the definition of the pixel value is defined by the actual needs.

Step S4 - The processing module 12 determines the true bright spot of the panel 2 for the resulting image. The method of judging is to analyze the position of the bright pixels P31 and P32 in the result image by using the image processing method, where the true bright point of the panel 2 is, and then output the position and the result image. This step can also be omitted, and the result image is directly output in step S3.

In summary, the bright pixel of the position representing the bright spot defect 21 and the foreign object 22 is obtained by capturing the transmitted image, and then the reflected image is captured to obtain a bright pixel representing the position of the foreign object 22, and can be excluded by image subtraction. The bright pixel representing the position of the foreign object 22 can further obtain the position of the bright spot defect 21, and the probability of false detection is reduced, so that the object of the present invention can be achieved.

The above is only the preferred embodiment of the present invention, and the scope of the present invention is not limited thereto, that is, the simple equivalent changes and modifications made by the patent application scope and patent specification content of the present invention, All remain within the scope of the invention patent.

1‧‧‧ Panel Highlight Detection System

11‧‧‧Image capture module

111‧‧‧First image capture unit

112‧‧‧Second image taking unit

12‧‧‧Processing module

13‧‧‧Light source module

131‧‧‧transmitted light source

132‧‧‧Reflective light source

14‧‧‧Polarizer

2‧‧‧ panel

21‧‧‧ Highlight defects

22‧‧‧ Foreign objects

3‧‧‧ Vehicles

Claims (7)

A panel bright spot detecting method is implemented by a panel bright spot detecting system and is suitable for detecting a panel. The system comprises an image capturing module, a processing module, a light source module, and a polarizer having an optical axis. The method includes the following steps: the image capturing module captures a transmitted image, and the transmitted image is formed by the image capturing module after the light emitted by the light source module is penetrated by the image capturing module; the image capturing module is formed by the image capturing module; And capturing a reflected image, wherein the reflected light is formed by the image capturing module when the light emitted by the light source module is reflected to form a reflected light, and the reflected light passes through the polarizing lens, and the reflected image is formed by the image capturing module. The light is linearly polarized light polarized in a first direction when there is no foreign matter on the surface of the panel, and the optical axis of the polarizer is perpendicular to the first direction, and the reflected light has foreign matter on the surface of the panel and is reflected by the foreign matter. Is a non-polarized light, the unpolarized light partially passes through the polarizer; and the processing module performs image subtraction, subtracting each pixel value of the reflected image from the pixel values of the transmitted image to form a result image. The method for detecting a bright spot of the panel according to claim 1, further comprising the following steps performed before capturing the reflected image: erecting the light source module, the polarizer and the image capturing module, so that the light emitted by the light source module is The Brewster angle is incident on the panel and reflected at the same angle, and the polarizer and the image capturing module are sequentially located on the path of the reflected light, and the optical axis of the polarizer is perpendicular to the first direction. The image taking module takes an image toward the light reflection and extracts the reflected light passing through the polarizer. The panel bright spot detecting method according to claim 1, wherein the image capturing module takes an image by line scanning. The panel bright spot detection system of claim 1, wherein the processing module further determines, by using the image processing method, a position of a pixel whose brightness is higher than four weeks or whose brightness value exceeds a threshold value by using the image processing method. . A panel bright spot detecting system is suitable for detecting a panel, comprising: a transmitting light source on a opposite side of the panel and a first image capturing unit, the light emitted by the transmitting light source is subjected to the first taking after penetrating the panel Forming a transmission image by the image unit; a reflection light source on the same side of the panel, a second image capturing unit, and a polarizer disposed before the second image capturing unit and having an optical axis, the reflection The light emitted by the light source is incident at a Brewster angle and is reflected at the same angle to form a reflected light, and the polarizer and the second image capturing unit are sequentially located on the path of the reflected light, and the second image capturing unit faces the light. Obtaining an image at the reflection, and extracting the reflected light passing through the polarizer to form a reflection image, wherein the reflected light is linearly polarized light polarized in a first direction without foreign matter on the surface of the panel, the polarized light of the polarizer The optical axis is perpendicular to the first direction, and the reflected light is a non-polarized light when the surface of the panel has a foreign object and is reflected by the foreign object, and the unpolarized light partially passes through the polarizer; and a processing module Performing a subtraction image, each pixel value of the transmission image by subtracting each pixel value of the reflected image to form a result image. The panel bright spot detection system of claim 5, wherein the first image is captured The unit and the second image capturing unit are respectively a line scan camera. The panel bright spot detection system of claim 5, wherein the processing module determines, by the image processing method, a position of a pixel whose brightness is higher than four weeks or whose brightness value exceeds a threshold value.