JP3761301B2 - Application state judgment device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is the application state of the applicationJudgment deviceFor example, the application state is determined by irradiating laser slit light from above diagonally across the coating and obtaining information on the cross section of the coating.To doAbout.
[0002]
[Prior art]
For example, when manufacturing a sealed container, various resins are used as the sealing material. FIG. 5 shows an example of the sealed container, and the sealed container 53 is configured by attaching a lid 52 to the housing 51. When this sealed container 53 is manufactured, the coated material 55 is applied to the collar portion 54 of the casing 51, and then the lid body 52 is attached, so that the casing 51 and the lid body 52 are sealed with a silicon-based resin. The sealed container 53 can be obtained.
[0003]
At this time, in order to obtain a good sealed state, it is important that the coated material 55 is applied in an appropriate state. That is, in the case of the sealed container 53 as shown in FIG. 5, it is desirable that the area of the cross section of the coated application 55 is the same regardless of the portion. Therefore, before the cover body 52 is attached, the application state of the applied application material 55 is inspected or determined.
[0004]
Conventionally, as a method for determining the application state of an application, for example, there is a technique disclosed in Japanese Patent Application Laid-Open No. 5-256619. This prior art is a method for determining the amount of cream solder applied, and the outline of the method is as follows. That is, the applied cream solder is irradiated with light, the size of the shadow caused by the solder is detected by a line sensor, and the volume of the solder is determined based on the detection result.
[0005]
Further, when the sealed container is an oil pan used in an automobile, an inspection method as shown in FIG. 6 is used. In this method, a silicone resin coating 64 squeezed and applied from the dispenser 63 to the collar 62 of the oil pan 61 is captured as an image by the image input device 65, and the image is processed and determined. Yes.
[0006]
[Problems to be solved by the invention]
However, since the technique disclosed in Japanese Patent Laid-Open No. 5-256619 uses a line sensor, it is affected by secondary reflection from the light source, and is required for accurate and stable detection. Has become an unsuitable technology.
[0007]
Further, in the case of image processing as used in the conventional inspection of the oil pan 61, an attempt to increase accuracy increases the complexity and cost of the image processing circuit. In addition, since the oil pan 61 is metal, bright objects around the ceiling lighting and the like are regularly reflected by the oil pan, and a processing error tends to occur during image processing. For this reason, in many automobile manufacturers, the inspection of the coated material 64 applied to the oil pan 61 is often made by visual inspection without using the image input device 65.
[0008]
The present invention is a coating state of a coating material that can accurately determine the coating state of the coating material without being affected by light existing in the environment.Judgment deviceThe purpose is to provide.
[0009]
[Means for Solving the Problems]
To solve this purpose,The coating state determination apparatus for a coated product according to the present invention includes a laser projector that irradiates a colored product with a colored laser slit light in a specific wavelength region from above obliquely across the coated product, and a colored laser slit that is reflected by the coated product. Color image input means for capturing light as an image, and reflected light of only the colored laser slit light is extracted from image data output from the color image input means based on color data registered in advance, and the extracted colored laser Color extraction means for outputting image data corresponding to the reflected light of the slit light, and information processing means for performing processing for determining the application state of the application based on the image data from the color extraction means are provided.
[0010]
Also,The application state determination apparatus of the present invention includes an image of a laser projector that irradiates a colored laser slit light having a specific wavelength range from above obliquely across the coated material, and the colored laser slit light reflected by the coated material. Color image input means that captures the image data, and the reflected image of only the colored laser slit light is extracted from the image data output from the color image input means based on the color data registered in advance, and the extracted colored laser slit light Color extraction means for outputting image data corresponding to the reflected light, and information processing means for performing processing for determining the application state of the application based on the image data from the color extraction means are provided.
[0014]
Claims2In the described invention, the claims1When the color extraction unit is set to the color extraction mode by the mode setting unit in the application state determination device described in the above, the reflected light of the colored laser slit light irradiated so as to cross the application is From the image data output by the image input means and output from the color image input means, the reflected light of only the colored laser slit light is extracted based on the color data registered in advance, and the reflected light of the extracted colored laser slit light is extracted. Is output from the color image input means when the color setting means is set to the color data registration mode by the mode setting means. Using the color data of the colored laser slit light as a reference, color data within a predetermined range that approximates the color data for the reference color data Sent to the color extraction means from the information processing means information about, in this color extraction means, and registers the information relating to the color data transmitted as the information regarding the color data within the allowable range of colored laser slit light.
[0015]
And claims3In the described invention, the claims2In the application state determination apparatus for the applied product, the predetermined range is changed by changing the relative ratio of the amount of the same color as the color of the laser slit light.
[0016]
The present invention is applied, for example, when determining the application state of an application material such as a silicon-based resin applied in a rod shape having a circular cross section as a sealing material. In order to achieve this, the reflected light obtained by irradiating the colored laser slit light across the coating is extracted based on the color data registered in advance, and image data for the extracted reflected light is obtained. Based on the image data, for example, the application state is determined by calculating the cross-sectional area of the application using a calculation process of a light cutting method.
[0017]
Thus, the present invention uses colored laser slit light, and compares the color data for the colored laser slit light output from the color image input means with the color data registered in advance, so that only the laser slit light is obtained. To take out. Therefore, by selecting the color of the laser slit light that is unlikely to exist in the usage environment such as the production line and capturing it with the color image input means, it is not affected by secondary reflection due to illumination on the production line. Only the laser slit light can be extracted efficiently, and the application state can be determined with high accuracy.
[0018]
In addition, on the basis of the color data of the image in which the colored laser slit light is taken as a reference, it is possible to register information relating to color data in a predetermined range that approximates the color data, and the registered color The reflected light of colored laser slit light is extracted based on the information about the data. For example, when red laser slit light is used, the output depends on the characteristics of the color image input means and the state of the applied material. Even if the color condition of the image data is somewhat different, if it is an approximate color, it can be treated as laser slit light. Thereby, it is possible to reliably extract only the laser slit light without being influenced by the characteristics of the color image input means, the state of the coated material, or the like.
[0019]
Furthermore, by determining the predetermined range for determining the laser slit light by changing the relative ratio of the amount of the same color as the color of the laser slit light, the determination of the approximation of the laser slit light is made more accurate. It is possible to extract only the laser slit light as the processing target light.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. In addition, what is shown in this embodiment is a case where the coating material 4 is apply | coated to the oil pan 1 as shown in FIG.
[0021]
The oil pan 1 used in the present invention is attached to the lower part of the engine part of an automobile. As shown in FIG. After being applied in a substantially circular (see FIG. 3) rod shape, it is pressed and fixed to the main body side.
[0022]
The outline of the coating method of the coating 4 and the inspection method of the coating state is as shown in FIG. That is, an image input device (CCD) which is attached to a robot operable in the XYθ direction and moves together with the dispenser 11 to the rear of the traveling direction (arrow A direction) of the dispenser 11 for squeezing the coating 4 and an image input means. (Camera etc.) 13 is provided to irradiate the laser slit light 12a so as to cross the laser slit light 12a at right angles to the coating 4 applied by being squeezed out from the dispenser 11.
[0023]
Then, the reflected light of the laser slit light 12a is captured by the image input device 13, and the height value H related to the height of the coated material 4 and the width value W corresponding to the width are measured by a light cutting method. Then, the application state is determined by determining the cross-sectional area of the application 4. 4A is a side view, FIG. 4B is a plan view, FIG. 4C is a partially enlarged view of FIG. 4B, and the image input device 13 is omitted in the plan view of FIG. Has been.
[0024]
In the method using this laser slit light 12a, it is not so difficult to extract only the laser slit light 12a from the image data output from the image input device 13 in a normal case. However, in the case of the oil pan 1, since the casing 2 that is an object to be applied is a metal, there is a risk that light from the ceiling illumination is reflected on the metal surface and cannot be distinguished from the laser slit light 12a. The invention is devised as described below.
[0025]
In order to eliminate the above-described danger, it is conceivable to use the colored laser slit light 12a and extract only the color data having the same color as the laser slit light 12a. When the slit light 12a is used and a red transmission filter is provided in front of the black and white camera to extract the red color of the laser, the red color of the laser can certainly be extracted, but it is a composite color of RGB (red / green / blue). Even when certain white light is input to the red transmission filter, an R (red) component is emitted, and the problem arises that the white light is also processed as the laser slit light 12a. Therefore, it cannot be coped with by optical means combining a monochrome camera and a filter.
[0026]
FIG. 1 is a configuration diagram for explaining an embodiment of the present invention in which such a risk is removed. As a schematic configuration, an image extraction unit 20, a changeover switch unit 21, and a color extraction unit serving as a color extraction unit. The unit 22 includes an information processing unit (such as a personal computer) 23 serving as information processing means, a monitor display unit 24, a keyboard 25, and the like. Note that the information processing unit 23 incorporates mode setting means for setting a mode to be described later.
[0027]
Here, the image take-out portion 20 is the same as that shown in FIG. 4 described above, and the coating material 4 such as a silicon resin is squeezed out onto the flange portion 3 of the casing 2 (hereinafter referred to as application surface 3). The dispenser 11, the laser projector 12 that moves with the dispenser 11 to the rear of the dispenser 11 in the traveling direction (arrow A direction), and irradiates the coating material 4 with the laser slit light 12 a obliquely from above, and the CCD that serves as a color image input means An image input device 13 such as a camera is provided.
[0028]
In this case, the laser slit light 12a emitted from the laser projector 12 is a colored laser slit light 12a having a specific wavelength range, and here, red laser light is used. The reason why the laser slit light 12a is red is that there is not much red light on the production line of the factory, and that a diode that generates stable red light can be obtained at a low price.
[0029]
Then, the laser slit light 12a is irradiated to the coating material 4 squeezed from the dispenser 11 and applied to the coating surface 3 so as to cross the coating material 4 at a right angle obliquely from above, and the laser slit light 12a generated by the coating material 4 is applied. The reflected light is captured by the image input device 13 and the image data is output.
[0030]
The image data from the image input device 13 is input to one terminal t 1 of the changeover switch unit 21 and written to the color graphic board 26 of the information processing unit 23.
[0031]
The changeover switch unit 21 is a changeover switch having terminals t1 and t2. Then, under the control of the mode setting means of the information processing unit 23, the terminal t1 and the terminal t1 of these terminals t1 and t2 are set and the color extraction unit 22 is set to the color extraction mode. The operation mode of the object application state determination apparatus is a color extraction mode including application state determination. On the other hand, when the changeover switch is set on the terminal t2 side and the color extraction unit 22 is set to the registration mode, the operation mode of the application state determination apparatus for the applied product in the present invention is set to the color data registration mode. In normal times, the color extraction mode is set on the terminal t1 side.
[0032]
The color extraction unit 22 receives red laser slit light 12a (actually reflected light from the coating 4 based on color data registered in advance from image data input via the changeover switch unit 21. In the following, “reflected light” is omitted and simply referred to as laser slit light) is extracted. In this color extraction, the color data registered in advance and the color data in the image data from the image input device 13 are compared, such as a white image for the red laser slit light 12a and a black image otherwise. Color extraction. That is, a white image is output only for the same image (or an image within a predetermined range) as color data registered in advance, and a black image is output for the other images. As a result, only the laser slit light 12a can be extracted from the image data as processing target image data.
[0033]
In addition, the color extracting unit 22 has a function of registering information related to color data in a predetermined range so that color data that approximates the reference color data in a predetermined range can be allowed with reference to certain color data. have. This will be described later.
[0034]
The information processing unit 23 is configured by a computer, and includes the above-described color graphic board 26 and the frame memory 27, and includes various components necessary for information processing, such as a CPU and mode setting means. ing. However, illustration and description of these components are omitted.
[0035]
Next, the operation of the application state determination apparatus for an application with such a configuration will be described.
[0036]
In the normal application state determination process, the dispenser 11 moves in the advancing direction (arrow A direction) while squeezing the application material 4. With the movement of the dispenser 11, a laser projector 12 provided behind the dispenser 11 and The image input device 13 moves. At this time, the laser projector 12 moves while irradiating the coating 4 coated with the red laser slit light 12a, and the image input device 13 takes in the laser slit light 12a and outputs the image data. Go while moving.
[0037]
The image data from the image input device 13 is input to the color graphic board 26 of the information processing unit 23 and is sent to the color extraction unit 22 via the changeover switch unit 21.
[0038]
The color extraction unit 22 outputs a monochrome binary image based on the color data from the transmitted image data. That is, if the color data of the image data is within the range of color data registered in advance, the image data is output as a white image, and if it is other color data, the image data is output as a black image. This black and white binary image data is stored in the frame memory 26 of the information processing unit 23.
[0039]
Then, using the binary image data stored in the frame memory 26, the height and width of the coating 4 are calculated using a method called a light cutting method, and the processing result such as the cross-sectional area is obtained. Note that the method for obtaining the height and width of an object by this light cutting method is a generally well-known method, and therefore the description of the method (calculation processing) is omitted here.
[0040]
Image data from the image input device 13 is also input to the color graphic board 26, and the value of the application state calculation result (result calculated by the light cutting method) based on the binary image data stored in the frame memory 27. And the display of the determination result (pass or fail) are overwritten on the color image (image captured by the image input device 13) on the color graphic board 26 and displayed on the monitor display unit 24.
[0041]
In this embodiment, the image capturing from the image input device 13 is performed 60 times per second for a total of 2,000 points per oil pan 1. Then, the image determined to be unacceptable is stored in the information processing unit 23. The person in charge of manufacturing the oil pan 1 appropriately reproduces the stored NG image on the monitor display unit 24 and confirms a defective portion of the coated material 4 that is too thick or too thin. If the defect status can be corrected, it is repaired. If the defect status cannot be corrected, the oil pan 1 is rejected and removed from the coating 4 or disposed of. It should be noted that other values can be adopted as appropriate for the values such as the number of image captures.
[0042]
The above is the contents of the normal application state determination process. In the present invention, the color extraction unit 22 performs the following process in order to accurately extract a white image indicating the laser slit light 12a.
[0043]
That is, in this embodiment, the red laser slit light 12a is used as the laser slit light, but the image data output from the image input device 13 depends on the characteristics of the image input device 13 and the state of the coating 4 or the like. There is also a possibility that the color data is slightly different from the red color emitted from the laser projector 12, such as dark red or light red with the same red color, or red with a little other color component mixed. .
[0044]
In order to cope with this, the color extraction unit 22 performs a process of learning that, if the color data is in a pre-registered allowable range, it is regarded as the laser slit light 12a to be treated. This process is performed in the color data registration mode described above, and is performed by operating the mode setting means to set the changeover switch of the changeover switch unit 21 to the terminal t2 side and to set the color extraction unit 22 to the registration mode. . Hereinafter, the color data registration mode will be described.
[0045]
First, in the state where the changeover switch is set to the terminal t1 side, the image input device 13 performs an operation of capturing the laser slit light 12a, and the color graphic board of the information processing unit 23 displays the captured color image of the laser slit light 12a. 26, and the color data is stored as reference color data.
[0046]
Next, the selector switch is switched to the terminal t <b> 2 side of the selector switch unit 21, and the reference color data stored in the color graphic board 26 of the information processing unit 23 is transferred to the color extracting unit 22 via the selector switch unit 21. The information processing unit 23 controls the color data transfer timing and setting of the color extraction unit 22 to the registration mode.
[0047]
Then, the information processing unit 23, as color data that approximates the reference color data with respect to the reference color data, for example, the amount of the same color as the color of the laser slit light 12a, that is, the relative ratio of red in the color data is little by little. Different color data is generated, and the color is displayed on the monitor display unit 24 and sent to the color extraction unit 22 via the changeover switch unit 21, and information about the color data is registered in the color extraction unit 22.
[0048]
In other words, if the user sets a limit hue value within the allowable range in advance for the reference color data, the color data having the hue value within the allowable range is automatically generated one after another. For example, assuming that the range of the limit hue value set by the user is 5 gradations in the plus direction and up to 5 gradations in the minus direction with respect to the hue of the reference color data, the information processing unit 23 thereafter performs reference Color data having different hue values for each tone gradation is output with respect to the color data, and information relating to the color data of the hue is registered in the color extraction unit 22 and displayed on the monitor display unit 24.
[0049]
The process of registering information regarding the color data for each tone gradation in the color extraction unit 22 is automatically performed by a control signal issued to the color extraction unit 22 by the information processing unit 23. By performing such processing, information relating to color data having a hue in a range (allowable range) set in advance with respect to the hue of the reference color data is registered in the color extraction unit 22.
[0050]
Thereby, the color extraction unit 22 determines whether or not the color data of the image data is within the registered range for the image data from the image input device 13, and the color is within the registered range. Is output as a binary image data of a white image, otherwise it is a black image.
[0051]
It should be noted that the color data of the predetermined range of hues can be registered simply by setting the allowable range by the user, and then automatically registering the color extraction unit 22 with information relating to color data having different hues. However, the color data to be registered may be displayed on the monitor display unit 24 each time and registered while the user sees it. Furthermore, the color to be registered in the color extracting unit 22 may be continuous or may be registered with skipped gradations, instead of every gradation.
[0052]
As described above, color data having an allowable range of hue with respect to the reference color data is registered in the color extraction unit 22.
[0053]
In this way, registration of the color data is completed, and the application state determination process similar to that described above is performed by setting the changeover switch unit 21 and the color extraction unit 22 to the color extraction mode again. That is, while applying the laser slit light 12a (red) to the application material 4 squeezed from the dispenser 11, the reflected light is captured by the image input device 13 and output as image data, and the image data is output to the information processing unit 23. Are written to the color graphic board 26 and given to the color extracting unit 22.
[0054]
The color extraction unit 22 performs color extraction from the transmitted image data. At this time, the color extraction unit 22 supplies the reference color data, that is, red laser slit light used in the apparatus. The color data obtained by actually acquiring 12a by the image input device 13 is used as reference color data, and color data of shades in an allowable range registered in advance is registered.
[0055]
Therefore, when performing color extraction from actually sent image data, the color data in the image data is compared with some already registered color data or color data within a predetermined range. If the existing color data exists in some of the registered color data or is within the registered allowable range, even if it is not exactly the same as the reference color data, 12a, the corresponding white image data is output to the information processing unit 23. As a result, the image data from the image input device 13 is stored in the frame memory 27 as binary image data in which only the portion corresponding to the laser slit light 12a is a white image and the other portion is a black image.
[0056]
Then, the information processing unit 23 calculates the height and width of the coating 4 by the light cutting method based on the binary image data stored in the frame memory 27, obtains the area of the cross section, and compares it with a predetermined reference value. Thus, the application state is determined.
[0057]
As described above, according to this embodiment, the red laser slit light 12a is irradiated so as to cross the coating material 4, and the reflected light is reflected when the relative ratio of the red amount is within a predetermined range. Since the light is extracted, only the laser slit light 12a can be reliably extracted. In other words, by selecting the red laser slit light 12a that is unlikely to exist in the usage environment such as the production line, and taking in the reflected light by the color image input means, secondary reflection by illumination on the production line, etc. Thus, it is possible to efficiently extract only the laser slit light 12a without being influenced by the above, and thereby it is possible to determine the application state with high accuracy.
[0058]
The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the gist of the present invention. For example, in the above-described embodiment, the laser beam is red, but this is not limited to red, and other colors may be used. However, when actually selecting a color, for example, a color that is less likely to exist in the use environment such as on a production line of a factory is preferable.
[0059]
Further, when setting the allowable range, if the allowable range is too wide with respect to the hue of the reference color, light other than the laser slit light 12a may be regarded as the laser slit light 12a. Consideration such as setting an appropriate allowable range according to the surrounding situation is necessary.
[0060]
Furthermore, in the above-described embodiment, the color data for determining whether or not the laser slit light 12a is used is different from the reference color data (in this case, red) in hue based on the relative ratio of the color. Although the example in which the color data is registered and the laser slit light 12a is determined to be within the set relative ratio, that is, within a predetermined density value range has been described, not only the density value of the reference color is varied. For example, some color data considering the relative ratio (= density value) of other predetermined colored components may be prepared and registered as color data approximate to the reference color data.
[0061]
Further, in the above-described embodiment, a silicon resin material is used as the applied material 4, and the silicon resin material is squeezed out into a rod shape with a circular cross section, and an application state determination is performed when applied to the oil pan 1. However, the present invention is not limited to this. For example, as the side to be applied, it may be a glass body such as a door glass of an automobile or a resin container, etc., and the applied material may be a cream-like solder for mounting electronic components, The present invention can also be applied to application state determination when cream-like solder is applied in a straight line shape or a dot shape.
[0062]
【The invention's effect】
Application state determination of the application according to claim 1apparatusAccording toLaser projector that emits colored laser slit light in a specific wavelength range so as to cross the coating material, image input means for capturing the colored laser slit light reflected by the coating material as an image, color extraction means, and this color extraction means Since the application state determination device is configured by an information processing means that processes image data from the image, the applied material on a metal object such as an oil pan that could not be conventionally determined by secondary reflection or the like This can be easily determined.
[0063]
Furthermore, in the present invention, since the laser projector, the color image input means, and the dispenser for squeezing the application are integrally driven, the state of the application can be determined quickly and continuously. In addition, since once captured image data can be supplied to the color extracting means, reference data or the like can be created based on the captured image data and registered in the color extracting means.
[0067]
In addition, the claims2In the described invention, if the mode setting unit is set to the color data registration mode, the information on the color data in a predetermined range that approximates the reference color data with reference to the color data of the colored laser slit light output from the image input unit. As a result, the laser slit light as the processing target light can be reliably obtained without being influenced by the subtle difference in the color of the reflected light of the laser slit light by the coating material or the characteristics of the image input device. Can be extracted.
[0068]
Claims3According to the described invention, the predetermined range value for determination is changed by changing the relative ratio of the amount of the same color as the color of the laser slit light. The laser slit light as the processing target light can be more reliably extracted without being influenced by the color difference or the characteristics of the image input means.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a coating material application state determining apparatus according to an embodiment of the present invention.
FIG. 2 is a perspective view showing an oil pan targeted by the application state determination apparatus for application and the state of the application in FIG. 1;
FIG. 3 is a partial cross-sectional view taken along line III-III in FIG.
4A and 4B are diagrams for explaining an application state detection method by the application state determination apparatus of FIG. 1, wherein FIG. 4A is a side view of an image capturing unit, FIG. 4B is a plan view thereof, and FIG. ) Is a partially enlarged view of (B).
FIG. 5 is a perspective view showing an example of a sealed container targeted by a conventional application state determination apparatus for an applied product.
FIG. 6 is a side view showing a conventional apparatus for determining the state of a coating applied on an oil pan.
[Explanation of symbols]
1 Oil pan
4 Application
11 Dispenser
12 Laser projector
12a Laser slit light
13 Image input device (color image input means)
21 Changeover switch
22 Color extraction unit (color extraction means)
23 Information processing section (information processing means)
24 Monitor display section
26 color graphic board
27 frame memory

Claims (3)

A laser projector that irradiates the coating material with a colored slit laser beam in a specific wavelength region obliquely from above, and a color image input unit that captures the colored laser slit light reflected by the coating material as an image; Then, from the image data output from the color image input means, the reflected light of only the colored laser slit light is extracted based on the color data registered in advance, and the image data corresponding to the extracted reflected light of the colored laser slit light A color extracting means for outputting the information, and an information processing means for performing a process of determining the application state of the application based on the image data from the color extraction means, the dispenser for squeezing the application being the laser projector and the dispenser In addition to being provided so as to be operable with a color image input means, the information processing means can generate color data of a plurality of colors. An application state determination of an applied product, characterized in that a mode setting unit is provided that can selectively supply either the image data from the color image input unit or the color data from the information processing unit to the color extraction unit. apparatus.  When the color extraction unit is set to the color extraction mode by the mode setting unit, the color image input unit captures reflected light from the colored laser slit light irradiated so as to cross the coating, From the image data output from the color image input means, the reflected light of only the colored laser slit light is extracted based on the color data registered in advance, and the image data corresponding to the extracted reflected light of the colored laser slit light is obtained. The color laser output from the color image input means when the color extraction means is set to a color data registration mode by the mode setting means. Using the color data of the slit light as a reference, the color data used as a reference is related to a predetermined range of color data that approximates the color data. Information is sent from the information processing means to the color extracting means, and the color extracting means registers information relating to the transmitted color data as information relating to color data within the allowable range of the colored laser slit light. The application | coating state determination apparatus of the coating material of Claim 1 to do.  3. The application state determination apparatus for an applied product according to claim 2, wherein the predetermined range is changed by changing a relative ratio of an amount of the same color as the color of the laser slit light.

Images