KR20190096666A - Metal sorting system using laser induced breakdown spectroscopy and operating method thereof - Google Patents

Abstract

According to the present invention, an operation method of a metal sorting system can comprise the following steps of: detecting colors of waste metal from a sensor; detecting a shape of the waste metal from a laser light and ranging (LIDAR) sensor; and selecting an irradiation location of a laser induced breakdown spectroscopy (LIBS) signal by using detected color information and detected shape information.

Description

Metal sorting system using laser induced collapse spectroscopy and its operation method TECHNICAL SORTING SYSTEM USING LASER INDUCED BREAKDOWN SPECTROSCOPY AND OPERATING METHOD THEREOF

The present invention relates to a metal classification system using laser induced collapse spectroscopy and a method of operation thereof.

Recently, recycling is a national focus project in terms of resource conservation and is being promoted not only in Korea but also worldwide. Existing waste resource screening technologies include plastic classification using near infrared ray, color classification using visible light, and metal classification using X-ray. In the case of electromagnetic sensors, metals and nonmetals can be classified, but not by metal. In order to replace this, there is a growing interest in a system that accurately and quickly classifies automatic sorting waste resources based on Laser Induced Breakdown Spectroscopy (LIBS) in real time. Laser Induced Breakdown Spectroscopy (LIBS) -based technology uses a spectrometer to collect plasma spectroscopy, since the spectral signal of plasma generated when irradiating nanosecond pulsed laser to the resource depends on the composition of the metal. It is a technique to find out the type and composition of metal by analyzing. However, when the surface of a resource to be irradiated with pulsed laser is contaminated or a part of other resources is different, the spectral signal is weakened or changed, which causes the classification accuracy to be deteriorated. In addition, some resources may not have enough space for laser irradiation.

Korean Patent Publication No. 10-2012-0063166, Publication Date: June 15, 2012 Name of the Invention: Separation and Collection Device for Metal Scrap Patent Publication: 10-2009-0095459, Publication date: September 08, 2009, the title of the invention: scrap automatic sorting device International Publication: WO / 2008/122622, Publication Date: October 16, 2008, Title: DEVICE AND METHOD FOR ANALYZING A HETEROGENEOUS MATERIAL BY MEANS OF LASER-INDUCED PLASMA SPECTROSCOPY

SUMMARY OF THE INVENTION An object of the present invention is to provide a metal classification system using laser induced collapse spectroscopy and a method of operating the same that improve the accuracy of metal classification.

An operation method of a metal classification system according to an embodiment of the present invention includes: detecting a color of waste metal from a detection sensor; Detecting the shape of the waste metal from a laser light and ranging (LIDAR) sensor; And selecting an irradiation position of a laser induced breakdown spectroscopy (LIBS) signal using the detected color information and the detected shape information.

In an embodiment, the detection sensor may include a 2D detection sensor.

In an embodiment, the LIDAR sensor may include a 2D sensor and a line laser, and may detect the shape of the waste metal by triangulation.

In example embodiments, the method may further include converting the 2D image plane detected by the 2D sensing sensor into a corresponding line laser image of the line laser.

The selecting of the irradiation position of the LIBS signal may include: receiving color profiles of the waste metal from the detection sensor; And receiving height profiles of the waste metal from the LIDAR sensor.

The selecting of the irradiation position of the LIBS signal may include: separating an object using the height profiles; Searching for a flat-high region from the separated object; And searching for a non-contaminated area from the color profiles.

In an embodiment, the searching of the flat-high region may include calculating a slope of each coordinate axis; And calculating an area larger than the average height.

The selecting of the irradiation position of the LIBS signal may include: matching the flat-high region with the non-contaminated region; Selecting the optimal irradiation position from the matched data; And detecting and determining the selected irradiation position.

The matching may include: resizing an image corresponding to the height profiles and an image corresponding to the color profiles; And performing image correlation on the height profiles data and the color profiles data.

In an embodiment, the method may further include classifying the iron or the magnetic material by the magnet.

Metal sorting system according to an embodiment of the present invention, the transfer device for transferring the waste metal; A sensing device for detecting the color and shape of the waste metal on a transfer device; A LIBS device for irradiating the waste metal with a LIBS signal using the detected color information and shape information and analyzing a component of the waste metal; A discharge device for discharging the waste metal classified using the component analysis information by the LIBS device; And an integrated controller for controlling the sensing device, the LIBS device, and the discharge device.

The sensing device may include: a first sensing sensor configured to output the color information of the waste metal; It may include a LIDAR sensor for outputting the shape information of the waste metal.

In an embodiment, the LIDAR sensor may include a second detection sensor and a line laser for detecting the height of the waste metal according to a triangulation method.

In an embodiment, the integrated controller may select an irradiation position of the LIBS signal using the color information and the shape information.

In an embodiment, the integrated controller may be configured to receive color profiles corresponding to the color information, height profiles corresponding to the shape information, separate an object from the height props, and flat-separate from the separated object. The irradiation position of the LIBS signal may be selected by searching for a high region, searching for a non-contaminated region from the color profiles, and matching the flat-high region with the non-contaminated region.

Metal sorting system and its operation method according to an embodiment of the present invention, it is possible to more accurately classify the waste metal by optimizing the LIBS irradiation location using color information and shape information.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings are provided to facilitate understanding of the present embodiment, and provide embodiments with a detailed description. However, the technical features of the present embodiment are not limited to the specific drawings, and the features disclosed in the drawings may be combined with each other to constitute a new embodiment.
1 is a block diagram illustrating a metal sorting system 100 according to an exemplary embodiment of the present invention.
FIG. 2 is a diagram illustrating an exemplary embodiment of the metal sorting system 100 illustrated in FIG. 1.
3 is a diagram illustrating a sensing device 120 according to an embodiment of the present invention.
4 is a diagram illustrating an exemplary operation principle of a general triangulation LIDAR.
5 is a view for explaining the physical meaning of the projection conversion of the integrated controller 150 according to an embodiment of the present invention.
FIG. 6 is a diagram for explaining a projection conversion principle of the integrated controller 150 according to an exemplary embodiment of the present invention.
7 is a diagram illustrating a process of selecting a laser irradiation position of the integrated controller 150 according to an embodiment of the present invention.
8 is a view for explaining the reason for separating the object according to an embodiment of the present invention.
9 is a diagram illustrating a process of calculating a flat-high area according to an embodiment of the present invention.
10 is a diagram illustrating a process of matching height profile data and color profile data according to an embodiment of the present disclosure.
FIG. 11 is a diagram illustrating a process of finally selecting and verifying measurement points in selected non-contaminated and flat high regions.
12 is a flowchart illustrating a method of operating a waste metal classification system 100 according to an embodiment of the present invention.

DETAILED DESCRIPTION Hereinafter, the contents of the present invention will be described clearly and in detail so that those skilled in the art can easily implement the drawings.

As the inventive concept allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to a specific disclosed form, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. Terms such as first and second may be used to describe various components, but the components should not be limited by the terms.

The terms may be used for the purpose of distinguishing one component from another component. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component. When a component is referred to as being "connected" or "connected" to another component, it may be directly connected to or connected to that other component, but it may be understood that another component may be present in the middle. Should be. On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that there is no other component in between.

Other expressions describing the relationship between components, such as "between" and "immediately between" or "neighboring to" and "directly neighboring", should be interpreted as well. The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise.

In this application, the terms "comprise" or "having" are intended to indicate that there is a feature, number, step, action, component, part, or combination thereof that is implemented, and that one or more other features or numbers are present. It should be understood that it does not exclude in advance the possibility of the presence or addition of steps, actions, components, parts or combinations thereof. Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as meanings consistent with the meanings in the context of the related art and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. .

For laser induced breakdown spectroscopy (LIBS) analysis of moving shapes and sizes and moving samples such as scrap metal scrap, it is advantageous to use a scanning mirror that can irradiate the laser beam at the desired location at high speed. Also, if the sample size is different, the focal size of the laser beam on the surface of each sample is changed and ultimately, the characteristics of the acquired signal are changed. Accordingly, the present invention discloses a real-time high-speed focal length control system for allowing a laser focus to always be located on a sample surface based on height information of each scrap.

1 is a block diagram illustrating a metal sorting system 100 according to an exemplary embodiment of the present invention. Referring to FIG. 1, the metal sorting system 100 may include a transfer device 110, a sensing device 120, a LIBS device 130, a discharge device 140, and an integrated controller 150.

The transfer device 110 may be implemented to transfer waste metal. In an embodiment, the conveying device 110 may comprise a conveyor belt.

The sensing device 120 may be implemented to detect the position, shape, and color of the waste metal on the belt.

The LIBS device 130 may be implemented to identify each metal component by irradiating the LIBS laser to the conveyed waste metal. The LIBS device 130 may be implemented by a focus control driving technique (auto-focus) and a scanning driving technique (Galvano). The focus control drive technique uses the principle that the distance between two lenses changes at high speed so that the focal length finally reaching the sample surface changes. Scanning drive technology utilizes the principle that the direction of laser irradiation is changed by the high-speed rotating motion of the mirror, which has two rotating motions. In addition, the LIBS device 130 may apply surface decontamination drive technology. Surface decontamination drive technology includes self-cleaning optimization and process technology that removes contaminants through high-power laser ablation of heavily contaminated surfaces and then measures LIBS signals.

The discharge device 140 may be implemented to discharge the waste metal into different collection boxes by type. For example, the discharge system 140 may include an air knife, kicker, or the like. In an embodiment, the waste metal may include copper, aluminum, stainless steel, or the like.

Integrated controller 150 may be implemented to control the overall operation of metal sorting system 100. In an embodiment, the integrated controller 150 may command a sample measurement to the sensing device 120 and receive information such as a sample input time, a sample position, a shape, and a color from the sensing device 120. In an embodiment, the integrated controller 150 may provide information about the irradiation position to the LIBS device 130 and receive spectroscopic information about the sample from the LIBS device 130. In an embodiment, the integrated controller 150 may transmit the sample discharge time and the selection result to the discharge device 140.

In an embodiment, the integrated controller 150 may be implemented in hardware / software / firmware.

Although not shown in FIG. 1, the metal classification system 100 may further include a magnet for primarily classifying iron and magnetic materials.

In the actual field, the color surface, shape, pollution degree, etc. are generated by mixing various kinds of resources.

FIG. 2 is a diagram illustrating an exemplary embodiment of the metal sorting system 100 illustrated in FIG. 1. The sensing device 120 and the LIBS device 130 may be connected to a fixed support and detect and analyze waste metal moving on the belt of the transport device 110. In an embodiment, the waste metal may be a nonferrous metal.

3 is a diagram illustrating a sensing device 120 according to an embodiment of the present invention. Referring to FIG. 3, the sensing device 120 may include a first image sensor 121, a first image sensor 122, a line laser 123, and a control unit 124.

The first image sensor 121 may include a 2D image sensor capable of acquiring color information at the front end. The first image sensor 121 may acquire an RGB value of the color of the resource. The vision algorithm can search for relatively high polluted parts of the resource surface based on the average or RGB distribution value of the resource surface. By irradiating the laser by avoiding the high contamination part found in this way, the classification accuracy of the resources can be improved. In addition, the 2D image sensor 121 may improve classification accuracy by developing an algorithm (eg, copper orange) that classifies resources based on the RGB distribution of the resource surface.

In addition, the first image sensor 121 may be implemented to combine the shape information of the waste metal with the color information in real time by controlling the measurement speed of the color sensor.

The line laser 122 may be implemented to irradiate the laser at any location.

The second image sensor 122 may include a 2D image sensor.

The control unit 123 may be part of the integrated controller 150 of FIG. 1.

The line laser 122, the second image sensor 123, and the control unit 123 may acquire height information and position information of the waste metal on the belt. The line laser 122 and the second image sensor 123 may be configured as triangulation LIDAR sensors. That is, the line laser 122 and the second image sensor 123 may acquire real-time shape information of the moving metal in movement using a triangulation principle.

4 is a diagram illustrating an exemplary operation principle of a general triangulation LIDAR. From the initial optical design, α, d, l, θ can be known. Where α is the angle from the object to the lens, d is the distance from the origin to the lens, l is the height profile of the object, and θ is the angle from the origin to the lens. At this time, the height h of the object satisfies the following equation.

Where f is the focal length and s is the pixel distance.

On the other hand, according to triangulation LIDAR, an optical problem (lens distortion) on the adjustment of height and width may be caused.

5 is a view for explaining the physical meaning of the projection conversion of the integrated controller 150 according to an embodiment of the present invention. W is a scale factor, x and y are coordinates to transform, and x 'and y' are transformed coordinates. h ₁ , h ₂ , h ₃ and h ₄ are rotation, scaling, shearing, reflection, h3 and h6 are translations, h7 and h8 are perspectives ) Coefficient.

FIG. 6 is a diagram for explaining a projection conversion principle of the integrated controller 150 according to an exemplary embodiment of the present invention. Referring to FIG. 6, projection conversion between a 2D image plane of an image sensor and a line laser plane of a line laser may be performed using a calibration board plate. As a result, the accuracy of the measurement of the object can be improved.

7 is a diagram illustrating a process of selecting a laser irradiation position of the integrated controller 150 according to an embodiment of the present invention. The process of selecting the laser irradiation position may be largely divided into receiving a height profile and a color profile for an object, calculating a search area, matching, and determining.

The height profile and the color profile for the object measured from the sensing device 110 may be received by the integrated controller 150.

The integrated controller 150 may receive a height profile for the object, separate the object, and then calculate a flat-high area. The integrated controller 150 may receive a color profile for the object and calculate an uncontaminated area.

The flat-high region and the non-contaminated region can then be matched. The optimal laser irradiation position can be selected from the matched data. Contamination verification for the selected irradiation position is performed and the result can be finally output.

8 is a view for explaining the reason for separating the object according to an embodiment of the present invention. In the case of recognizing a plurality of objects, the measurement time for the same object is long, and as a result, the object sorting speed can be reduced. Because of this, objects must be separated from each other. Labeling algorithms can be used to move an object into a chunk of the object as the window moves around the image.

FIG. 9 is a diagram illustrating a process of calculating flat high and uncontinuous areas according to an exemplary embodiment of the present invention.

Optically flat points should be selected and blind spots avoided to improve LIBS measurement signals. After separation of the objects is made, the slopes of the X and Y axes can be calculated from the height map. Slope areas smaller than 20 ° can be calculated. At the same time an area larger than the average height can be calculated from the height map. From the calculated results, a flat-high region can be calculated.

10 is a diagram illustrating a process of matching height profile data and color profile data according to an embodiment of the present disclosure. Referring to FIG. 10, resizing may be performed for optical error correction, and image correlation may be performed for encoder correction.

FIG. 11 is a diagram illustrating a process of performing final selection verification on selected non-contaminated and flat high regions. Referring to FIG. 11, the final selection is a process of finding peak points by weighting after normalizing RGB values, height values, and slope values.

12 is a flowchart illustrating a method of operating a waste metal classification system 100 according to an embodiment of the present invention. 1 to 12, an operation method of the waste metal classification system 100 is as follows.

The sensing device 120 may detect the color of the waste metal (S110). In addition, the sensing device 120 may detect the shape of the waste metal (S120). The LIBS irradiation position may be selected using the color information and the shape information of the detected waste metal (S130). Thereafter, component analysis of the waste metal is performed from the LIBS device 130, and based on this, the waste metal classification may be determined.

The steps and / or actions according to the invention may occur simultaneously in different embodiments in different order, in parallel, or for other epochs, etc., as would be understood by one of ordinary skill in the art. Can be.

In some embodiments, some or all of the steps and / or actions may be directed to instructions, programs, interactive data structures, clients, and / or servers stored on one or more non-transitory computer-readable media. At least some may be implemented or performed using one or more processors. One or more non-transitory computer-readable media may be illustratively software, firmware, hardware, and / or any combination thereof. In addition, the functionality of the "module" discussed herein may be implemented in software, firmware, hardware, and / or any combination thereof.

One or more non-transitory computer-readable media and / or means for implementing / performing one or more operations / steps / modules of embodiments of the present invention may be used in application-specific integrated circuits (ASICs), standard integrated circuits, A controller that performs appropriate instructions, including a microcontroller, and / or an embedded controller, field-programmable gate arrays (FPGAs), complex programmable logic devices (CPLDs), and the like. Does not.

On the other hand, the content of the present invention described above is only specific embodiments for carrying out the invention. The invention will include not only specific and practically available means per se, but also technical ideas as abstract and conceptual ideas that may be utilized in future technology.

100: metal sorting system
110: transfer device
120: sensing device
130: LIBS device
140: discharge device
150: integrated controller

Claims (15)

In the method of operating the metal sorting system:
Detecting the color of the waste metal from the detection sensor;
Detecting the shape of the waste metal from a laser light and ranging (LIDAR) sensor; And
And selecting an irradiation position of a laser induced breakdown spectroscopy (LIBS) signal using the detected color information and the detected shape information. The method of claim 1,
The sensing sensor comprises a 2D sensing sensor. The method of claim 1,
And the LIDAR sensor comprises a 2D sensing sensor and a line laser, and detecting the shape of the waste metal by triangulation. The method of claim 3, wherein
Projection converting the 2D image plane detected by the 2D sensing sensor into a corresponding line laser image of the line laser. The method of claim 1,
Selecting the irradiation position of the LIBS signal,
Receiving color profiles of the waste metal from the detection sensor; And
Receiving height profiles of the waste metal from the LIDAR sensor. The method of claim 5,
Selecting the irradiation position of the LIBS signal,
Separating the object using the height profiles;
Searching for a flat-high region from the separated object; And
Searching for a non-contaminated area from the color profiles. The method of claim 6,
Navigating the flat-high region,
Calculating slopes for each coordinate axis; And
Calculating an area greater than the average height. The method of claim 6,
Selecting the irradiation position of the LIBS signal,
Matching the flat-high region with the non-contaminated region;
Selecting the optimal irradiation position from the matched data; And
Detecting and determining the selected irradiation position. The method of claim 8,
The matching step,
Resizing an image corresponding to the height profiles and an image corresponding to the color profiles; And
Performing image correlation on the height profiles data and the color profiles data. The method of claim 1,
And classifying the iron or the magnetic substance by a magnet. A conveying device for conveying waste metal;
A sensing device for detecting the color and shape of the waste metal on a transfer device;
A LIBS device for irradiating a laser induced breakdown spectroscopy (LIBS) signal to the waste metal using the detected color information and shape information, and analyzing the components of the waste metal;
A discharge device for discharging the waste metal classified using the component analysis information by the LIBS device; And
And an integrated controller for controlling said sensing device, said LIBS device, and said discharge device. The method of claim 11,
The sensing device,
A first sensor for outputting the color information of the waste metal;
And a LIDAR sensor for outputting the shape information of the waste metal. The method of claim 12
The LIDAR sensor comprises a second detection sensor and a line laser for detecting the height of the waste metal according to a triangulation method. The method of claim 11,
The integrated controller,
And the irradiation position of the LIBS signal is selected using the color information and the shape information. The method of claim 14,
The integrated controller,
Receive color profiles corresponding to the color information, height profiles corresponding to the shape information, separate an object from the height props, search a flat-high region from the separated object, and color profiles Search for a non-contaminated area from the device and select an irradiation position of the LIBS signal by matching the flat-high area with the non-contaminated area.

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