CN112858312B - Pen cap silicon bead installation visual detection device and method - Google Patents

Abstract

The invention relates to a visual detection device and method for installing a silicon bead on a pen cap. The device comprises a camera, a host computer, a fixing bracket for installing the camera, and a workbench for installing and fixing a pen cap to be tested. The light source is located at the pen cap installation position on the worktable, the camera is connected to the upper computer through a transmission line, and the upper computer is configured to perform the following steps: when the ring light source is lit, receive the axial image of the pen cap to be tested collected by the camera; The image is processed by grayscale and binary value in turn; the area of the silicon bead area of the pen cap is calculated, and if it is less than the threshold, the abnormal value is output. Compared with the prior art, the present invention illuminates the pen cap from the end of the pen cap through a ring light source, then collects the axial image of the pen cap from the opening of the pen cap, and performs grayscale and binary processing in turn to realize the silicon bead by the area of the silicon bead part. Visual detection of whether the installation angle is correct greatly improves the detection efficiency of silicon beads.

Description

A visual detection device and method for the installation of silicon beads in a pen cap

technical field

The invention relates to the field of stationery manufacture and detection, in particular to a visual detection device and method for the installation of silicon beads on a pen cap.

Background technique

In the production of gel pens, the installation of the cap silicon bead is one of the necessary processes, and the cap silicon bead is an important part to protect the pen head. The silicon beads of the pen cap are installed at an inclination, and the silicon beads are very easy to fall off during subsequent use, which will make the fragile pen tip lose its protection, and will be bruised by impact, which will seriously affect the writing life of the gel pen.

At present, in the process of installing the silicone beads of the gel cap, the installation of the silicone beads of the pen cap is generally detected by manual inspection, so as to screen out the defective products. However, the manual screening method has large workload, low work efficiency and low accuracy, and the detection speed is difficult to meet the production requirements. Moreover, the existing detection methods also have problems such as ambiguous criteria for judging eligibility, inaccurate detection due to observation angle and clarity, and low accuracy and efficiency caused by uncontrollable human factors.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a visual detection device and method for the installation of silicon beads in a pen cap, which illuminates the pen cap from the end of the pen cap through a ring light source, and then collects the axial image of the pen cap from the opening of the pen cap, and undergoes grayscale and binary processing in turn. , The visual inspection of whether the installation angle of the silicon beads is correct is realized through the area of the silicon bead part, which greatly improves the detection efficiency of the silicon beads.

The object of the present invention can be realized through the following technical solutions:

A pen cap silicon bead installation visual inspection device, comprising a camera, a host computer, a fixing bracket for installing the camera, and a worktable for installing and fixing the pen cap to be tested, the worktable is provided with a ring light source, and the ring light source is located on the worktable. At the installation position of the pen cap on the upper computer, the camera is connected to the upper computer through a transmission line, and the upper computer is configured to perform the following steps:

When the ring light source is lit, an axial image of the pen cap to be tested collected by the camera is received, wherein the image is captured from the direction of the opening of the pen cap;

Perform grayscale processing and binarization processing on the collected images in turn;

Based on the binarized image, the area of the silicon bead region of the pen cap is calculated, and if it is less than the threshold, an abnormal value is output.

The threshold is specifically:

为所有硅珠安装正常的情况下的笔帽硅珠区域的面积的平均值，α为比例系数，取0.9-1。Where: ST is the threshold,

It is the average value of the area of the silicon bead area of the pen cap under normal conditions for all silicon beads, and α is the scale factor, which is 0.9-1.

The α is 0.95.

The axial image contains all the regions of the cap silicon beads.

The worktable is an annular rotatable worktable, and a plurality of pen cap installation positions are arranged on the annular rotatable worktable, and each pen cap installation position is provided with an annular light source.

The upper computer is a PC.

An automatic detection method for the installation of silicon beads in a pen cap, comprising:

When the ring light source is lit and axially illuminates the cap to be tested from the closed end of the cap to be tested, receiving an axial image of the cap to be tested collected by the camera, wherein the image is captured from the direction of the opening of the cap;

Perform grayscale processing and binarization processing on the collected images in turn;

Based on the binarized image, the area of the silicon bead region of the pen cap is calculated, and if it is less than the threshold, an abnormal value is output.

Compared with the prior art, the present invention has the following beneficial effects:

1) The pen cap is illuminated from the end of the pen cap by a ring light source, and then the axial image of the pen cap is collected from the opening of the pen cap. After grayscale and binary processing in turn, the area of the silicon bead part is used to realize the visual inspection of whether the installation angle of the silicon bead is correct. , greatly improving the detection efficiency of silica beads.

2) The threshold is dynamically generated, which can realize self-learning and improve detection accuracy.

3) Cut a part of the area for area calculation, reduce the amount of calculation and reduce performance requirements

4) The annular rotatable worktable is adopted to improve the detection efficiency.

Description of drawings

1 is a schematic structural diagram of an embodiment of the present invention;

Fig. 2 is an image grayscale processing effect diagram in the embodiment;

Fig. 3 is the image binarization processing effect diagram in the embodiment;

Fig. 4 is the actual collection diagram in the embodiment;

Among them: 1. Fixed bracket, 2. Pen cap to be tested, 3. Ring light source, 4. Ring-shaped rotatable worktable, 5. Camera, 6. Host computer.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. This embodiment is implemented on the premise of the technical solution of the present invention, and provides a detailed implementation manner and a specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

A pen cap silicon bead installation visual detection device, as shown in Figure 1, includes a camera 5, a host computer 6, a fixing bracket 1 for installing the camera 5, and a workbench for installing and fixing the pen cap to be tested, and a ring-shaped ring is arranged on the workbench. Light source 3, the ring light source 3 is located at the pen cap installation position on the worktable, and the camera 5 is connected to the host computer 6 through a transmission line. As shown in Figures 2 to 4, the host computer is configured to perform the following steps:

When the ring light source 3 is lit, the axial image of the pen cap 2 to be tested collected by the camera 5 is received, wherein the image is captured from the opening direction of the pen cap;

Perform grayscale processing and binarization processing on the collected images in turn. After binarization, the silicon bead part is black and the rest is white;

Based on the binarized image, the area of the silicon bead region of the pen cap is calculated, and if it is less than the threshold, an abnormal value is output.

When the silicon bead is installed obliquely, its projected area on the axial section will be reduced. Therefore, in the present application, the pen cap is illuminated from the end of the pen cap by a ring light source, and then the axial image of the pen cap is collected from the opening of the pen cap, and the grayscale and Binary processing, through the area of the silicon bead part, realizes the visual detection of whether the installation angle of the silicon bead is correct, which greatly improves the detection efficiency of the silicon bead.

In some embodiments, the threshold is dynamically generated, which can realize self-learning and improve detection accuracy. The specific threshold is:

为所有硅珠安装正常的情况下的笔帽硅珠区域的面积的平均值，α为比例系数，取0.9-1。Where: ST is the threshold,

It is the average value of the area of the silicon bead area of the pen cap under normal conditions for all silicon beads, and α is the scale factor, which is 0.9-1.

For example, in one embodiment, α is determined to be 0.95 based on the variance and standard deviation.

The ring light source 3 can evenly generate light with strong brightness and radiate outward, and the light intensity is uniform within a certain horizontal range. In some embodiments, the focal length of the lens of the camera 5 is 16mm. Of course, in other embodiments, it can also be greater than 16mm. ;The image processing part in the host computer is mainly written by the open source algorithm OpenCV; the transmission line has conventional data interface and trigger device interface, the data interface is connected with the host computer 6, the trigger device is connected with the external trigger signal, and the fixed bracket 1 is similar to the general camera bracket .

After the image is grayscaled, the grayscale values of the pixels on the image are between 0 and 255. This type of image usually presents a clear black and white effect, with 0 representing the lowest brightness and a black tail, and 255 representing the brightest and white. By changing the height and angle of the light source, any pixel with a pixel value within this range can theoretically be displayed to form images of different gray levels. After the binarization process is adopted, the area of the image formed by the different inclination angles of the silicon beads on the pen cap will also be different. The image is subjected to grayscale processing, and the collected image is converted into a grayscale image. Due to the uniform radiation ring light source, there is a significant difference in brightness between the silicon bead part and the non-silicon bead part. After converting to a grayscale image, the brightness of the silicon bead part is obvious. lower.

In some embodiments, the region of interest includes all the silicon beads of the pen cap. According to the difference in brightness between the silicon bead part and the non-silicon bead part, a pen cap is selected to frame the entire silicon bead part, and the frame also includes a little non-silicon bead part. Bead part, adjust the size of the frame to ensure the complete acquisition of the silicon bead image, which can reduce the amount of calculation and performance requirements

In some embodiments, the worktable is an annular rotatable worktable 4 , and a plurality of pen cap installation positions are provided on the annular rotatable worktable 4 , and each pen cap installation position is provided with an annular light source 3 .

In some embodiments, the host computer 6 is a PC, which is easier to implement.

When using this application, the steps are as follows:

1) Fix the camera. Adjust the size of the fixture of the fixing bracket 1, and fix the camera 5 to the bracket vertically, with the lens downward, according to the position of the pen cap and the distance between the pen caps, adjust the height of the camera and adjust the focal length of the camera by moving the bracket fixture up and down, so that the camera The silicon bead part of the pen cap can be photographed at the same time and clearly displayed on the LCD monitor;

2) Fixed light source. Keep the height of the camera 5 and the position of the pen cap 2 to be tested unchanged, illuminate the end of the pen cap with a light source, so that the brightness of the silicon bead part and the non-silicon bead part displayed on the display screen is different, so that the silicon bead part is brighter than the non-silicon bead part. Lower, adjust the height and angle of the light source to make the difference more obvious, and fix the light source at this time;

3) Transfer the photographed picture to the host computer 6, firstly, the grayscale processing of the picture is performed by the grayscale image processing system. The grayscale image was converted to a binarized image (the silicon bead part is black and the rest is white). According to the binarized image, the area of the black silicon bead part (the area is represented by the number of pixels) is calculated. The black silicon bead part of the pixels is larger than 96212, that is, the qualified pen cap is installed.

4) Connect the trigger signal of the pen cap transmission device to the camera through the transmission line. When a trigger signal is transmitted, it means that there is a new pen cap sample. At the same time, the camera takes a picture, completes a signal acquisition, and then transmits it to the grayscale image in the industrial computer. The processing system performs processing and sets the standard silicon bead installation image area range according to the sample pen cap. If the image area is larger than 212 pixels, the logic value "1" will be output, otherwise, the logic value "0" will be output, and the "invalid" value will be output if no image is detected. , so repeatedly;

5) The processed result is then transmitted to the pen cap transmission device, the pen caps whose output logic result is "1" are retained, and the pen caps whose output logic result is "0" are rejected.

Claims (9)

1. The utility model provides a pen cap silica bead installation visual detection device, its characterized in that includes camera (5), host computer (6), is used for installing fixed bolster (1) of camera (5) to and the fixed workstation of the pen cap that awaits measuring of installation, be equipped with annular light source (3) on the workstation, this annular light source (3) are located the pen cap installation position department on the workstation, camera (5) pass through transmission line connection with host computer (6), the host computer is configured to carry out following step:

when the annular light source (3) is lightened, receiving an axial image of the pen cap (2) to be detected, which is acquired by a camera (5), wherein the image is shot from the opening direction of the pen cap, and the axial image contains a region of pen cap silica beads;

carrying out gray level processing and binarization processing on the acquired image in sequence;

and calculating the area of the pen cap silica bead region based on the image after the binarization processing, and outputting an abnormal value if the area is smaller than a threshold value.

2. The pen cap silica bead mounting visual inspection device of claim 1, wherein the threshold is specifically:

wherein: ST is a threshold value and is used as a threshold value,

the average value of the areas of the pen cap silica bead areas under the condition that all silica beads are normally installed is shown, alpha is a proportionality coefficient, and the proportionality coefficient is 0.9-1.

3. The pen-cap silica bead mounted visual inspection device of claim 2, wherein said α is 0.95.

4. The pen cap silicon bead installation visual inspection device according to claim 1, wherein the workbench is an annular rotatable workbench (4), a plurality of pen cap installation positions are arranged on the annular rotatable workbench (4), and an annular light source (3) is arranged at each pen cap installation position.

5. The pen cap silica bead mounting visual inspection device according to claim 1, wherein the upper computer (6) is a PC.

6. An automatic detection method for pen cap silicon bead installation is characterized by comprising the following steps:

when the annular light source (3) is lightened and the pen cap (2) to be detected is axially irradiated from the closed end part of the pen cap (2) to be detected, an axial image of the pen cap (2) to be detected, acquired by a camera (5), is received, wherein the image is obtained by shooting from the opening direction of the pen cap, and the axial image contains a region of pen cap silica beads;

carrying out gray level processing and binarization processing on the acquired image in sequence;

and calculating the area of the pen cap silica bead region based on the image after the binarization processing, and outputting an abnormal value if the area is smaller than a threshold value.

7. The automatic detection method for installation of the pen cap silicon bead as claimed in claim 6, wherein the threshold specifically is:

wherein: ST is a threshold value and is a threshold value,

the average value of the areas of the pen cap silica bead areas under the condition that all silica beads are normally installed is shown, alpha is a proportionality coefficient, and the proportionality coefficient is 0.9-1.

8. The automatic detection method for pen cap silica bead installation according to claim 7, wherein α is 0.95.

9. The method according to claim 6, wherein the axial image contains all areas of the pen cap silica beads.

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