Laser cleaning method for outer surface of automobile lampshade

Abstract

The invention relates to the field of laser cleaning, in particular to a laser cleaning method for the outer surface of an automobile lampshade. Comprising the following steps: S1, traversing and scanning an automobile lampshade image, and determining an automobile lampshade pollutant area; s2, performing traversal scanning on the pollutant area of the automobile lampshade to obtain a 3D morphology image of pollutants; s3, comparing to obtain an accurate pollutant area; s4, distance signals between all coordinate points of the accurate pollutant area and the pulse laser are measured, the focal length of the pulse laser is adjusted based on the distance signals so that the pulse laser can be gathered on the surface of the automobile lampshade, optimal laser cleaning parameters are determined according to pollutant parameters, and laser cleaning is conducted; s5, the automobile lampshade is blown or sucked; and S6, automobile lampshade pollutant parameters are obtained and compared with all parameters before current cleaning, whether the requirements are met or not is judged, and if not, the step S4 is executed again. In the cleaning process, proper laser cleaning parameters can be automatically selected, automatic focusing is achieved, and the cleaning effect and efficiency are improved.

Description

Technical Field

[0001] The invention relates to the field of laser cleaning, and in particular to a laser cleaning method for the outer surface of an automobile lamp cover. Background Art

[0002] The lampshade is an indispensable component of the car. However, the surface of the car lampshade will be oxidized or contaminated with dirt during long-term use, which will affect the light transmission and reduce the focusing ability. If it is not resolved in time, it will cause traffic accidents. Therefore, it is particularly important to maintain and clean the car lampshade.

[0003] Laser cleaning technology uses the high-frequency vibration generated by a laser of a certain wavelength to shatter pollutants attached to the surface of an object, and uses the instantaneous high temperature generated by the laser to peel off the attached objects from the surface of the object, thereby achieving the purpose of cleaning. Laser cleaning does not come into direct contact with the workpiece, can be cleaned remotely, and does not produce secondary pollution without chemical cleaning agents. It has gradually gained attention. For example, in the patent application number CN202211139366.8, the patent name is a laser cleaning device and method for automobile headlights. The laser light curtain forms a local high temperature on the surface of the headlight cover, so that the stain layer on the lampshade falls off.

[0004] However, this patent has two major disadvantages. First, the surface of the car headlight is a curved surface, and the laser cleaning may be inaccurate in focus, resulting in poor cleaning effect. Second, it is impossible to select appropriate cleaning parameters according to the specific stain situation. If the laser energy is too low, the cleaning efficiency will be low, and if the laser energy is too high, it will easily damage the lampshade substrate. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a laser cleaning method for the outer surface of a car lampshade, which can automatically select appropriate laser cleaning parameters and automatically focus during the cleaning process to improve the cleaning effect and cleaning efficiency.

[0006] In order to solve the above technical problems, the technical solution of the present invention is: a laser cleaning method for the outer surface of an automobile lampshade, comprising:

[0007] Step S1, traversing and scanning the image of the automobile lampshade, and measuring and quantifying the grayscale value of each pixel of the image to obtain a digital image of the automobile lampshade, determining the pollutant area of ​​the automobile lampshade based on the quantized grayscale value, and performing light and dark field processing on the digital image;

[0008] Step S2, scanning the pollutant area of ​​the automobile lampshade to obtain a 3D topographic image of the pollutant;

[0009] Step S3, comparing the 3D topographic image with the digital image after bright and dark field processing to obtain the precise pollutant area;

[0010] Step S4, measuring the distance signal between each coordinate point of the precise pollutant area of ​​the automobile lampshade and the pulse laser, adjusting the focal length of the pulse laser based on the distance signal to make it focus on the surface of the automobile lampshade, determining the optimal laser cleaning parameters according to the pollutant parameters, and performing laser scanning cleaning on the precise pollutant area;

[0011] Among them, the pollutant parameters include pollutant type and depth data, and the pollutant type and depth data are obtained based on the 3D topography image;

[0012] Step S5, blowing or vacuuming the car lamp cover;

[0013] Step S6, obtaining the precise pollutant area and depth data of the automobile lampshade, comparing with the parameters before the current cleaning, and judging whether the cleaning requirements are met. If not, returning to step S4.

[0014] Further, the digital image is processed by light and dark fields; specifically,

[0015] The polluted area in the digital image is processed as a bright image, and the part of the digital image other than the polluted area is processed as a dark image.

[0016] Further, step S4 also includes:

[0017] Monitor the cleaning temperature of the car lampshade surface in real time, and stop cleaning when the temperature reaches the set threshold.

[0018] Further, in step S4, the distance signal between each coordinate point of the precise pollutant area of ​​the automobile lampshade and the pulse laser is measured, and the focal length of the pulse laser is adjusted based on the distance signal so that it is focused on the surface of the automobile lampshade; specifically:

[0019] The instant distance signal of each coordinate of the surface of the precise contaminated area is measured by a rangefinder. The instant distance signal is delayed according to the distance between the rangefinder and the pulse laser and the laser cleaning speed. Based on the delayed distance signal, the focal length of the pulse laser is adjusted to focus on the surface of the car lampshade.

[0020] Further, in step S4, the optimal laser cleaning parameters are determined according to the contaminant parameters; specifically,

[0021] Build the relationship between pollutant parameters and optimal laser cleaning parameters based on previous experiments or deep learning algorithms and store them in the database;

[0022] The corresponding optimal laser cleaning parameters are called from the database according to the current pollutant parameters.

[0023] Further, in step S4, the laser cleaning parameters include power, scanning speed, pulse frequency and number of cleaning times.

[0024] Further, in step S1, the image of the automobile lampshade is traversed and scanned by a line scanner;

[0025] In step S2, the pollutant area of ​​the automobile lampshade is traversed and scanned using a dot matrix laser radar and a high-definition microscope camera;

[0026] In step S4, a distance meter is used to measure the distance signal between each coordinate point of the precise pollutant area of ​​the automobile lampshade and the pulse laser.

[0027] Furthermore, in the process of scanning the automobile lampshade in step S1, the motion platform drives the automobile lampshade to move, and the line scanner remains stationary;

[0028] In step S2, during the process of traversing and scanning the pollutant area, the motion platform drives the car lampshade to move, and the dot matrix laser radar and the high-definition microscope camera remain stationary;

[0029] Step S4 is a process of laser scanning and cleaning the precise pollutant area. The motion platform drives the car lampshade to move, and the pulse laser and the rangefinder remain stationary.

[0030] Furthermore, a line scanner, a dot-matrix lidar, a high-definition microscope camera, a pulse laser, and a rangefinder are integrated on the same carrying box.

[0031] After adopting the above technical scheme, the present invention determines the approximate pollutant area through the first traversal scan, and determines the 3D morphological image of the pollutants in the pollutant area through the second scan, thereby being able to obtain the precise pollutant area and pollutant parameters such as the type and thickness information of the pollutants. During the pulse laser scanning and cleaning of the precise pollutant area, the distance signal is measured and the focal length of the pulse laser is adjusted to make it focus on the surface of the automobile lampshade. The optimal laser cleaning parameters are determined according to the pollutant parameters, and the precise pollutant area is laser cleaned. The method of the present invention avoids the disadvantage of poor cleaning effect caused by the difficulty in controlling the focusing position of the laser beam due to the uneven surface (curved surface), effectively ensures the uniformity and quality of the surface of the laser-cleaned lampshade, and can call the optimal laser cleaning parameters according to the pollutant parameters, greatly improving the cleaning efficiency, and avoiding damage to the automobile lampshade substrate, and the cleaning cost is low, the pollution is small, and it is conducive to large-scale industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The present invention is a flow chart of the laser cleaning method for the outer surface of an automobile lamp cover. DETAILED DESCRIPTION

[0033] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments in conjunction with the accompanying drawings.

[0034] like Figure 1 As shown, a laser cleaning method for the outer surface of a car lampshade is based on a laser cleaning device. The laser cleaning device includes a carrying box and a line scanner, a dot matrix laser radar, a high-definition microscope camera, a pulse laser, a purging device, a temperature measuring device, a delay device, a focusing device and a laser rangefinder all integrated on the carrying box. The laser rangefinder is located on the right side of the pulse laser, the focusing device is coaxial with the laser rangefinder, and the purging device can be a fan device, etc.

[0035] Methods include:

[0036] Step S0, the car lampshade to be cleaned is installed on the motion platform, and the carrying box is hoisted above the car lampshade to be cleaned and kept stable;

[0037] Step S1, the motion platform drives the car lampshade to move. In this process, the line scanner is used to traverse and scan the image of the car lampshade, and its grayscale value is measured at each pixel position in the image. The grayscale value is converted into a discrete integer through an analog-to-digital converter, that is, quantization is achieved to obtain a digital image of the car lampshade. Based on the quantized grayscale value, the pollutant area of ​​the car lampshade is determined, and the digital image is processed by light and dark fields. Specifically, the light and dark field processing is to process the polluted area in the digital image as a bright image, and the part of the digital image other than the polluted area is processed as a dark image. At this time, the polluted area can be easily distinguished from other parts. The polluted area obtained in this step is the approximate pollutant range.

[0038] Step S2, the motion platform drives the car lampshade to move again. During this process, the pollutant area of ​​the car lampshade is traversed and scanned by using a dot matrix laser radar and a high-definition microscope camera to obtain a 3D morphological image of the pollutant;

[0039] Specifically, the dot matrix laser radar and the high-definition microscope camera work simultaneously, and after traversal scanning, a 3D morphology image and a two-dimensional microscopic image of the pollutant area are obtained respectively. The images taken by the two can be compared and fused. After processing, only the 3D morphology image of the pollutant is retained in the image, which is used for the subsequent training of deep learning models and comparison of database parameters, as well as for comparison with digital images after light and dark field processing.

[0040] Step S3, comparing the 3D topographic image of the pollutant with the digital image after bright and dark field processing to obtain the precise pollutant area;

[0041] Specifically, the approximate pollutant range obtained in step S1 is not accurate enough, but it can reduce the workload for the second dot matrix lidar scan (step S2). By comparing the image data of the two scans, the final accurate pollutant area can be obtained.

[0042] Step S4, the motion platform drives the car lampshade to move again. During this process, the rangefinder is used to measure the instantaneous distance signal of each coordinate of the surface of the precise contaminated area. The instantaneous distance signal is delayed according to the distance between the rangefinder and the pulse laser and the laser cleaning speed. The focal length of the pulse laser is adjusted based on the delayed distance signal to make it focus on the surface of the car lampshade. Then, the optimal laser cleaning parameters are determined according to the pollutant parameters, and the precise pollutant area is laser cleaned; and the cleaning temperature of the car lampshade surface is monitored in real time. When the temperature reaches the set threshold, the cleaning is stopped to prevent the power from being too large and damaging the substrate. The set threshold can be 150°C.

[0043] Among them, the pollutant parameters include pollutant type and pollutant depth data, and the pollutant type and depth data are obtained based on the 3D topography image;

[0044] More specifically, the thickness is calculated from the coordinate data in the 3D topographic image of the pollutant; the type of pollutant, such as sludge, dirt, dust, etc., is obtained by comparing the sample library or through a trained deep learning model.

[0045] Laser cleaning parameters include power, scanning speed, pulse frequency and number of cleanings. The specific steps to determine the optimal laser cleaning parameters are to construct the relationship between the pollutant parameters and the optimal laser cleaning parameters based on previous experiments or deep learning algorithms, and store them in the database; then call the corresponding optimal laser cleaning parameters from the database according to the current pollutant parameters. In a specific example, the optimal laser cleaning parameters called are: power range: 10W-2000W, scanning speed (cleaning speed): 500-10000mm / s, pulse frequency: 1000-1500kHz, number of cleanings: 5-10 times. Use a low-power and low-speed cleaning mode for multiple cleanings.

[0046] In this step, the delay device gives the pulse laser sufficient time to automatically adjust the focus. After the focusing device has adjusted the focus, the pulse laser continues to process, ensuring that the focus position conditions for curved surface laser cleaning are met, thereby perfectly solving the problem of focus offset for curved surface cleaning and avoiding the disadvantage of damaging the substrate surface due to the difficulty in controlling the laser beam focus position due to the uneven surface. The process of focusing the focusing device is to move the focus mirror position inside it in real time to automatically adjust the laser focus position.

[0047] Step S5, using dust removal equipment to blow or vacuum the automobile lampshade;

[0048] This step mainly uses high-speed airflow blowing or suction to deal with the oxide layer debris residues generated during the processing, and can even blow away the oxide layer that has been completely fluffy but not completely fallen off.

[0049] Step S6, obtain the precise pollutant area and depth data of the car lampshade (refer to step S2 and step S3 for the acquisition method), compare with the parameters before the current cleaning, and determine whether the cleaning requirements are met. If not, return to step S4.

[0050] The method in this embodiment avoids the disadvantage of poor cleaning effect caused by difficulty in controlling the focusing position of the laser beam due to uneven surface (curved surface), effectively ensures the uniformity and quality of the laser-cleaned lampshade surface, and can call the optimal laser cleaning parameters according to the pollutant parameters, greatly improving the cleaning efficiency and avoiding damage to the automobile lampshade substrate. The cleaning cost is low and the pollution is small, which is conducive to large-scale industrial application.

[0051] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A laser cleaning method for the outer surface of a car lampshade, characterized in that: include: Step S1, traversing and scanning the image of the automobile lampshade, and measuring and quantifying the grayscale value of each pixel of the image to obtain a digital image of the automobile lampshade, determining the pollutant area of ​​the automobile lampshade based on the quantized grayscale value, and performing light and dark field processing on the digital image; Step S2, scanning the pollutant area of ​​the automobile lampshade to obtain a 3D topographic image of the pollutant; Step S3, comparing the 3D topographic image with the digital image after bright and dark field processing to obtain the precise pollutant area; Step S4, measuring the distance signal between each coordinate point of the precise pollutant area of ​​the automobile lampshade and the pulse laser, adjusting the focal length of the pulse laser based on the distance signal to make it focus on the surface of the automobile lampshade, determining the optimal laser cleaning parameters according to the pollutant parameters, and performing laser scanning cleaning on the precise pollutant area; Among them, the pollutant parameters include pollutant type and depth data, and the pollutant type and depth data are obtained based on the 3D topography image; Step S5, blowing or vacuuming the car lamp cover; Step S6, obtaining the precise pollutant area and depth data of the automobile lampshade, comparing with the parameters before the current cleaning, and judging whether the cleaning requirements are met. If not, returning to step S4.

2. The laser cleaning method for the outer surface of a car lampshade according to claim 1, characterized in that: Perform light and dark field processing on digital images; specifically, The polluted area in the digital image is processed as a bright image, and the part of the digital image other than the polluted area is processed as a dark image.

3. The laser cleaning method for the outer surface of a car lampshade according to claim 1, characterized in that: Step S4 also includes: Monitor the cleaning temperature of the car lampshade surface in real time, and stop cleaning when the temperature reaches the set threshold.

4. The laser cleaning method for the outer surface of a car lampshade according to claim 1, characterized in that: In step S4, the distance signal between each coordinate point of the precise pollutant area of ​​the automobile lampshade and the pulse laser is measured, and the focal length of the pulse laser is adjusted based on the distance signal so that it is focused on the surface of the automobile lampshade; specifically: The instant distance signal of each coordinate of the surface of the precise contaminated area is measured by a rangefinder. The instant distance signal is delayed according to the distance between the rangefinder and the pulse laser and the laser cleaning speed. Based on the delayed distance signal, the focal length of the pulse laser is adjusted to focus on the surface of the car lampshade.

5. The laser cleaning method for the outer surface of a car lampshade according to claim 1, characterized in that: In step S4, the optimal laser cleaning parameters are determined according to the contaminant parameters; specifically, Build the relationship between pollutant parameters and optimal laser cleaning parameters based on previous experiments or deep learning algorithms and store them in the database; The corresponding optimal laser cleaning parameters are called from the database according to the current pollutant parameters.

6. The laser cleaning method for the outer surface of a car lampshade according to claim 1, characterized in that: In step S4, the laser cleaning parameters include power, scanning speed, pulse frequency and number of cleaning times.

7. The laser cleaning method for the outer surface of a car lampshade according to claim 1, characterized in that: In step S1, the image of the automobile lampshade is traversed and scanned by a line scanner; In step S2, the pollutant area of ​​the automobile lampshade is traversed and scanned using a dot matrix laser radar and a high-definition microscope camera; In step S4, a distance meter is used to measure the distance signal between each coordinate point of the precise pollutant area of ​​the automobile lampshade and the pulse laser.

8. The laser cleaning method for the outer surface of a car lampshade according to claim 7, characterized in that: In step S1, during the process of traversing and scanning the car lampshade, the motion platform drives the car lampshade to move, and the line scanner remains stationary; In step S2, during the process of traversing and scanning the pollutant area, the motion platform drives the car lampshade to move, and the dot matrix laser radar and the high-definition microscope camera remain stationary; Step S4 is a process of laser scanning and cleaning the precise pollutant area. The motion platform drives the car lampshade to move, and the pulse laser and the rangefinder remain stationary.

9. The laser cleaning method for the outer surface of a car lampshade according to claim 8, characterized in that: The line scanner, dot matrix lidar, high-definition microscope camera, pulse laser and rangefinder are integrated on the same carrying box.

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