Welding visualization system and welding mask having the welding visualization system

Abstract

To provide a welding visualization system that can respond to various types of welding.SOLUTION: A welding visualization system includes a camera unit including a plurality of bandpass filters that transmit light in different wavelength bands, and an imaging device that captures images for each different wavelength band of the plurality of bandpass filters, an image processing unit that synthesizes images captured in different wavelength bands, and a display unit that displays the images synthesized by the image processing unit. The plurality of bandpass filters may include a first bandpass filter that transmits light in the ultraviolet band, a second bandpass filter that transmits light in the visible light band, and a third bandpass filter that transmits light in the infrared band.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] One embodiment of the present invention relates to a system for photographing and visualizing the state of welding, and a welding mask having the system.

Background Art

[0002] Welding includes arc welding in which an arc discharge is generated between a base material and a welding rod (wire), and gas welding in which a combustible gas such as acetylene and oxygen are burned to melt the base material by the flame. Since these weldings emit light rays accompanied by radiant heat, the welded part cannot be directly visually recognized. Usually, an operator performs welding while applying a welding mask to the face and observing the welded part through a light-shielding glass. However, since the visibility is poor through the light-shielding glass, it is difficult to know the state of welding, and in fact, the judgment of the quality of welding depends on the experience of the operator.

[0003] On the other hand, a system has been disclosed in which, instead of an operator observing the welded part through a light-shielding glass, a camera is used to photograph the welded part and the welding state is visualized in real time (see Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Since the arcs and gas flames generated during welding are highly luminous, attempting to capture them with a normal camera poses a problem as the dynamic range is insufficient and the video signal saturates. The welding visualization system disclosed in Patent Document 1 addresses this problem by using a neutral density filter for imaging. However, since the emission spectrum of the welding location changes depending on the material being welded and the type of arc welding or gas welding, simply reducing the light intensity may cause a change in visibility. As a result, there is a problem that an appropriate image cannot be obtained and the quality control of welding cannot be adequately performed.

[0006] In view of such problems, an embodiment of the present invention aims to provide a welding visualization system that can respond to various types of welding. Another object is to provide a welding mask having such a welding visualization system.

Means for Solving the Problems

[0007] A welding visualization system according to an embodiment of the present invention includes a camera unit including a plurality of band-pass filters that transmit light in different wavelength bands and an image sensor that captures images for each different wavelength band of the plurality of band-pass filters, an image processing unit that synthesizes the images captured for each different wavelength band, and a display unit that displays the image synthesized by the image processing unit.

[0008] The plurality of band-pass filters may include a first band-pass filter that transmits light in the ultraviolet band, a second band-pass filter that transmits light in the visible light band, and a third band-pass filter that transmits light in the infrared light band. The camera unit may have a wavelength conversion unit that converts light in the ultraviolet band into light in the visible light band, and the wavelength conversion unit may be configured to convert the transmitted light of the first band-pass filter into visible light so that the image sensor can capture images. A filter control unit that sequentially switches a plurality of filter units may be included.

[0009] A welding visualization system according to an embodiment of the present invention includes a plurality of camera units each including a band-pass filter and an image pickup device corresponding to each band-pass filter, an image processing unit that synthesizes images captured by the plurality of camera units, and a display unit that displays the image synthesized by the image processing unit.

[0010] The plurality of camera units may include a first camera unit including a first band-pass filter that transmits light in the ultraviolet band and a first image pickup device, a second camera unit including a second band-pass filter that transmits light in the visible light band and a second image pickup device, and a third camera unit including a third band-pass filter that transmits light in the infrared band and a third image pickup device. The first camera unit may have a wavelength conversion unit that converts light in the ultraviolet band into light in the visible light band, the wavelength conversion unit converts the transmitted light of the first band-pass filter into visible light, and the first image pickup device may be configured to perform imaging.

[0011] The welding visualization system may be configured such that the image processing unit binarizes the image with a predetermined threshold value and weights the data values of the binarized pixels.

[0012] The welding visualization system can be mounted on a welding mask.

Advantages of the Invention

[0013] According to an embodiment of the present invention, by photographing a welded portion by combining a plurality of optical filters that pass light in a specific wavelength band, it is possible to provide a welding visualization system that can respond to various welding conditions.

Brief Description of the Drawings

[0014]

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Embodiments for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present invention will be described with reference to the drawings and the like. However, the present invention can be implemented in many different modes and is not to be construed as being limited to the description of the embodiments exemplified below. The drawings may be schematically represented in terms of the width, thickness, shape, etc. of each part compared to the actual mode in order to make the explanation clearer, but this is merely an example and does not limit the interpretation of the present invention. Also, in this specification and each figure, the same reference numerals may be given to the same elements as those described above with respect to the already shown figures, and detailed explanations may be omitted as appropriate. Furthermore, the letters "first" and "second" appended to each element are for convenience of distinguishing each element and have no further meaning unless otherwise specified.

[0016] [First Embodiment] FIG. 1 shows a block diagram for explaining the configuration of a welding visualization system 100a according to an embodiment of the present invention. The welding visualization system 100a includes a camera unit 102, an image processing unit 104, a display unit 106, a filter control unit 108, and a data storage unit 110. The camera unit 102 includes an imaging device 112, a filter unit 118, a wavelength conversion unit 116, and a lens unit 114. Further, the filter unit 118 includes a band-pass filter 1181. The filter unit 118 may also include an ND filter (neutral density filter) 1182.

[0017] In the welding visualization system 100a, the camera unit 102 photographs the welding part 200, the image processing unit 104 performs image processing on the photographed data, and the image is displayed on the display unit 106. The camera unit 102 can photograph both the moving image and the still image of the welding part 200. The display unit 106 includes a display for displaying the image photographed by the camera unit 102. The display may be a normal direct-view display or a VR (Virtual Reality) display (head-mounted display). The image processing unit 104 also has a function of storing the image data in the data storage unit 110. The filter control unit 108 performs control to appropriately switch the band-pass filter 1181 and the ND filter 1182 when the camera unit 102 takes a photograph. The filter control unit 108 performs control to switch the insertion / non-insertion operation of the wavelength conversion unit in synchronization with the switching operation of the band-pass filter 1181.

[0018] The imaging device 112 used in the camera unit 102 is, for example, a CMOS image sensor. The lens unit 114 has an optical system that projects an image onto the imaging surface of the imaging device 112, and preferably has a zoom optical system in order to enlarge and photograph the welded portion 200. In order for the camera unit 102 to photograph the arc of welding, the image will be saturated with only the combination of the imaging device 112 and the lens unit 114. Since the band-pass filter 1181 transmits light in a specific band, the light emission of the welded portion 200 is attenuated. An ND filter 1182 may be used to further attenuate the light incident on the imaging device 112.

[0019] The camera unit 102 does not simply photograph the welded portion 200, but photographs an image in a specific wavelength band. It is known that the arc or gas flame generated during welding has a wide spectrum ranging from the ultraviolet band to the visible light and infrared bands. The welding visualization system 100 visualizes the state of welding by photographing an image in a specific wavelength band with the band-pass filter 1181, and also enables the state of welding to be observed in more detail.

[0020] The filter unit 118 includes a band-pass filter 1181 that can select a plurality of wavelength bands. The band-pass filter 1181 includes, for example, a first band-pass filter 1181a that transmits a specific band within the ultraviolet band (wavelength 380 nm or less), a second band-pass filter 1181b that transmits a specific band within the visible light band (roughly 380 nm to 780 nm), and a third band-pass filter 1181c that transmits a specific band within the infrared light band (780 nm or more). The band-pass filter 1181 is not limited to this example, and may include a plurality of band-pass filters having different transmission wavelength bands within each band.

[0021] The imaging element 112 is provided with a filter for capturing color images and is normally configured such that it cannot directly capture ultraviolet light. Therefore, when the aforementioned first band-pass filter 1181a is selected as the band-pass filter 1181, the camera unit 102 is configured such that a wavelength conversion unit is inserted between the imaging element 112. The wavelength conversion unit 116 is configured using a scintillator or a phosphor. The filter unit 118 and the wavelength conversion unit 116 are controlled in operation by the filter control unit 108, and when the first band-pass filter 1181a is selected, the wavelength conversion unit 116 is inserted in front of the imaging element 112 in synchronization therewith.

[0022] Figure 2 schematically shows the configuration of the camera unit 102. The camera unit 102 has a configuration in which a filter unit 118, a wavelength conversion unit 116, a lens unit, and an imaging element 112 are arranged from the light incident side.

[0023] The filter unit 118 includes a plurality of band-pass filters 1181. Figure 2 shows that the plurality of band-pass filters 1181 include a first band-pass filter 1181a, a second band-pass filter 1181b, and a third band-pass filter 1181c. The plurality of band-pass filters 1181 each have a different transmission wavelength band. For example, the first band-pass filter 1181a transmits light in the ultraviolet band, the second band-pass filter 1181b transmits light in the visible light band, and the third band-pass filter 1181c transmits light in the infrared light band. The filter unit 118 includes a drive mechanism such that the first band-pass filter 1181a, the second band-pass filter 1181b, and the third band-pass filter 1181c are arranged to be switched on the optical path of the incident light. Note that although Figure 2 shows three band-pass filters with different transmission light bands, the present invention is not limited to this example, and the filter unit 118 may further include more types of band-pass filters.

[0024] The wavelength conversion unit 116 includes a wavelength conversion element 1161. As described above, the wavelength conversion element 1161 is composed of a scintillator or a phosphor. When irradiated with ultraviolet light, the wavelength conversion element 1161 has the property of converting it into light in the visible light band and emitting it. The wavelength conversion unit 116 includes a drive mechanism that enables the wavelength conversion element 1161 to be moved in and out of the optical path of the incident light. When the first band-pass filter 1181a is installed on the optical path, the wavelength conversion unit 116 arranges the wavelength conversion element 1161 on the optical path in synchronization with this. The switching of such a band-pass filter 1181 and the operation of the wavelength conversion unit 116 are controlled by the filter control unit 108 shown in FIG. 1.

[0025] When the camera unit 102 photographs the welded part, when the first band-pass filter 1181a is arranged on the optical path of the incident light, light in the ultraviolet band passes through and enters the wavelength conversion element 1161. The wavelength conversion element 1161 converts the light in the ultraviolet band into light in the visible light band, and the converted light enters the imaging element 112 through the lens unit 114. The camera unit: does not directly photograph the ultraviolet component of the arc or gas flame generated during welding, but photographs it after converting it into visible light. As a result, the welding situation that could not be seen conventionally can be visually recognized.

[0026] FIG. 3 shows the configuration of the image processing unit 104. The image processing unit 104 includes a processor 120 (first processor 120a, second processor 120b), a system memory 122, a cache memory 124, an input / output interface 126, and a network interface 128.

[0027] The system memory 122 is configured to store programs accessible by the first processor 120a. The program describes an instruction set that implements the functions of the welding visualization system. The system memory 122 is composed of non-volatile memory. The first processor 120a reads the program from the system memory 122 and controls the operations of the camera unit 102 and the filter unit 118. Also, as will be described later, the first processor 120a processes the image data output from the camera unit 102. The image processing unit 104 may be provided with a dedicated second processor (GPU) 120b for performing image processing at high speed. The cache memory 124 is used for temporarily storing image data.

[0028] The input / output interface 126 has a function of transmitting or receiving data and transmitting control commands between the display unit 106, the camera unit 102, the filter control unit 108, and the data storage unit 110. For example, image data is input from the camera unit 102 to the input / output interface 126. The image data is temporarily stored in the cache memory 124, and image processing is performed by the second processor 120b. The image data after image processing is output to the display unit 106 via the input / output interface 126. Also, the image data after image processing is stored in the data storage unit 110 via the input / output interface 126.

[0029] The image processing unit 104 may include a network interface 128. The network interface 128 is used for connection to a communication network (telecommunication line) such as the Internet. The image processing unit 104 has a function of transmitting image data to the terminal device 130 via the communication network. The image processing unit 104 can output, via the communication network, an image captured by the camera unit 102 and processed by the second processor 120b to the terminal device 130. In other words, the terminal device 130 can view in real time an image captured by the camera unit 102 via the image processing unit 104. Further, the image processing unit 104 has a function of reading out image data from the data storage unit 110 and transmitting the image data to the terminal device 130 via the communication network.

[0030] The terminal device 130 is a computer device capable of screen display such as a personal computer, a desktop computer, a laptop computer, a notebook computer, a tablet terminal, a smartphone, etc. The welding visualization system 100a can also transmit a command from such a terminal device 130 and capture an image of the welded part with the camera unit 102.

[0031] Incidentally, the emission spectrum of the welded part varies depending on the type and conditions of the welding. FIG. 4(A) shows a schematic example of the emission spectrum in arc welding (for example, MAG (Metal Active Gas) welding using an active gas as a shielding gas). In arc welding, the emission spectrum is large at wavelengths of 550 nm or less, and in particular, a strong emission spectrum is observed in the ultraviolet band with wavelengths of 400 nm or less. On the other hand, FIG. 4(B) schematically shows the spectrum of argon-hydrogen mixed gas arc welding, and characteristic spectra are observed around 480 nm and around 660 nm.

[0032] The welding visualization system 100a of this embodiment does not simply reduce the light intensity of the light emission of the soluble part having the spectrum shown in FIGS. 4(A) and 4(B) and then take a photograph. Instead, one or more specific wavelength bands are selected by a band-pass filter, and preferably, image data is generated by synthesizing images taken in a plurality of wavelength bands. For example, as shown in FIG. 4(A), the camera unit 102 includes first image data taken by filtering light (ultraviolet light) with a wavelength of 275 to 325 nm by the first band-pass filter 1181a, converting it into visible light by the wavelength conversion element 1161, second image data taken by filtering light (visible light) with a wavelength of 550 to 600 nm by the second band-pass filter 1181b, and third image data taken by filtering light (near-infrared light) with a wavelength of 775 - 825 nm by the third band-pass filter 1181c. In this embodiment, since there is one camera unit 102, the band-pass filter 1181 is switched at high speed to sequentially photograph each wavelength band.

[0033] Also, in the example shown in FIG. 4(B), since the emission spectrum is concentrated in the visible light band, a plurality of band-pass filters are used in the visible light band. For example, in the camera unit 102, photographing is performed using a band-pass filter that filters light in the wavelength band of 475 - 500 nm, a band-pass filter that filters light in the wavelength band of 560 - 575 nm, and a band-pass filter that filters light in the wavelength band of 650 - 675 nm.

[0034] In this way, by photographing light in a specific wavelength band with a band-pass filter, the amount of light incident on the imaging element can be suppressed, and the lack of dynamic range can be eliminated.

[0035] Note that FIGS. 4(A) and 4(B) are examples. In the band-pass filter 1181, there is no limitation on the wavelength band to be selected and the number of selected wavelength bands, but it is preferable to take a plurality of images in different wavelength bands.

[0036] Figures 5(A) and (B) show an overview of the image processing performed by the image processing unit 104. The first image data 132 shown in Figure 5(A) is image data captured with light in the ultraviolet band, the second image data 134 is image data captured with light in the visible band, and the third image data 136 is image data captured with light in the infrared band. The image processing unit 104 reads these image data and performs image processing (S201). Then, the three image data are combined (S202), and the image is displayed on the display unit (S203). The image data includes both still images and moving images. Note that Figure 5(A) illustrates image data in three bands as image data, but there is no limitation on the type and number of image data. For example, there may be multiple image data in the visible band, or the image data in the ultraviolet band may be omitted.

[0037] Figure 5(B) shows an example of the image processing in step S201. The image processing first binarizes the image data with a predetermined threshold value to detect the range of the welding area in the image (S2011). Then, the data within the detected range is multiplied by a weight count (S2012). For example, for the image data obtained by photographing a welded part having a spectrum as shown in Figure 4(A) in three bands of the ultraviolet band, visible light band, and infrared band, the brightness of the image data in the visible light band and infrared band is lower than that of the image data in the ultraviolet band. Therefore, by performing a process of increasing the brightness of the image data in the visible light band as weighting, it is possible to generate image data with a clear contour after synthesis.

[0038] Also, as shown in Figures 4(A) and (B), since the brightness varies depending on the wavelength band to be photographed, as weighting, the brightness of the image data with low brightness may be adjusted to become brighter so that the brightness is leveled, and the data with high brightness may be weighted to become darker. By performing such adjustment, even when the arc of welding does not occur, the state of the welded part can be continuously visualized through the camera unit.

[0039] The welding visualization system 100a according to this embodiment can visualize the welding state by photographing the welded part by combining a plurality of optical filters that transmit light in a specific wavelength band, and selecting and photographing light in a narrow wavelength band according to the emission spectrum of the welded part.

[0040] [Second Embodiment] This embodiment shows an example of a welding visualization system 100b in which the configuration of the camera unit 102 is different from that of the first embodiment. In the following description, the description will focus on the differences from the first embodiment.

[0041] FIG. 6 shows the configuration of the welding visualization system 100b according to this embodiment. This welding visualization system 100b includes a first camera unit 102a, a second camera unit 102b, and a third camera unit 102c. The first camera unit 102a includes a first imaging device 112a, a first lens unit 114a, a wavelength conversion unit 116, and a first filter unit 118a. The first filter unit 118a includes a first band-pass filter 1181a having a transmission wavelength band in the ultraviolet band. Further, the first filter unit 118a may include a first ND filter 1182a. The first imaging device 112a photographs an image that has passed through the first band-pass filter 1181a and has been wavelength-converted to visible light by the wavelength conversion unit.

[0042] The second camera unit 102b includes a second imaging device 112b, a second lens unit 114b, and a second filter unit 118b. The second filter unit 118b includes a second band-pass filter 1181b having a transmission wavelength band in the visible light band. Further, the second filter unit 118b may include a second ND filter 1182b. The third camera unit 102c includes a third imaging device 112c, a third lens unit 114c, and a third filter unit 118c. The third filter unit 118c includes a third band-pass filter 1181c having a transmission wavelength band in the infrared band. Further, the third filter unit 118c may include a third ND filter 1182c.

[0043] As described above, the welding visualization system 100b according to this embodiment includes a camera unit that captures images in each wavelength band of the ultraviolet band, visible light band, and infrared band. As a result, it becomes possible to simultaneously capture images in each wavelength band, and images (still images and moving images) of the welded portion 200 can be obtained in a clearer state. Further, since the optical filters of the first camera unit 102a, the second camera unit 102b, and the third camera unit 102c are fixed, the filter switching unit can be omitted.

[0044] The welding visualization system 100b according to this embodiment is the same as the welding visualization system 100a according to the first embodiment except for the configuration of the camera unit, and the same operational effects can be obtained.

[0045] [Third Embodiment] This embodiment shows an example of a welding mask 150 having a welding visualization system. In this embodiment, as an example, a welding mask 150 equipped with the welding visualization system 100b shown in the second embodiment is shown.

[0046] FIG. 7(A) shows the welding mask 150 according to this embodiment. The welding mask 150 has a welding visualization system 100b attached to the protective surface 152. The welding mask 150 has a camera unit 102 (first camera unit 102a, second camera unit 102b, third camera unit 102c) attached at a position corresponding to the height of the eyes when worn on the face. Since the camera unit 102 can capture moving images in real time, the operator can perform work with a normal line of sight.

[0047] FIG. 7(B) shows the configuration of the welding visualization system 100c attached to the welding mask 150. The welding visualization system 100b includes a first camera unit 102a, a second camera unit 102b, and a third camera unit 102c disposed on the front side of the welding mask 150, an image processing unit 104 installed at a position lower than the head, the back of the head, the side of the head, or the jaw of the welding mask 150, and a display unit 106 installed at the height of the eyes inside the welding mask 150. Since the display unit 106 is disposed close to the face, it is preferably a goggle-type display (VR display). Further, the display unit 106 may be fixed inside the welding mask 150, or may be separate from the welding mask 150, and a head-mounted display directly worn by the operator may be used.

[0048] By using the welding mask 150 according to the present embodiment, the operator can visually confirm the welding state in real time. Further, by capturing an image in real time with the camera unit 102 and displaying it on the display system, the operator does not need to put on and take off the welding mask every time of welding work (work of actually generating an arc and welding), so that welding can be continuously performed and workability can be improved.

[0049] In addition, although this embodiment shows an example in which the welding visualization system 100b according to the second embodiment is attached to the welding mask 150, the welding visualization system 100a according to the first embodiment can be similarly applied.

Industrial Applicability

[0050] The welding visualization system 100a according to the first embodiment and the welding visualization system 100b according to the second embodiment can be applied to a welding robot. That is, by analyzing a clear image captured by the camera unit 102, precise control of the welding robot can be performed. Further, by mounting an artificial intelligence on the welding robot and making it learn the images when a skilled worker welds, the welding robot can inherit the welding technique of the skilled worker.

Explanation of Signs

[0051] 100: Welding visualization system, 102: Camera unit, 102a: First camera unit, 102b: Second camera unit, 102c: Third camera unit, 104: Image processing unit, 106: Display unit, 108: Filter control unit, 110: Data storage unit, 112: Image sensor, 112a: First image sensor, 112b: Second image sensor, 112c: Third image sensor, 114: Lens unit, 114a: First lens unit, 114b: Second lens unit, 114c: Third lens unit, 116: Wavelength conversion unit, 1161: Wavelength conversion element, 118: Filter unit, 118a: First filter unit, 118b: Second filter unit, 118c: Third filter unit, 1181: Band-pass filter, 1181a: First band-pass filter, 1181b: Second band-pass filter, 1181c: Third band-pass filter, 1182: ND filter, 1182a: First ND filter, 1182b: Second ND filter, 1182c: Third ND filter, 120: Processor, 122: System memory, 124: Cache memory, 126: Input / output interface, 128: Network interface, 130: Terminal device, 132: First image data, 134: Second image data, 136: Third image data, 150: Welding mask, 152: Protective face, 200: Weld joint

Claims

1. A camera unit including a plurality of band-pass filters that transmit light in different wavelength bands, and an image sensor that performs imaging for each different wavelength band of the plurality of band-pass filters; An image processing unit that synthesizes the images captured for each of the different wavelength bands; A display unit that displays the image synthesized by the image processing unit; comprising: The plurality of band-pass filters include a first band-pass filter that transmits light in the ultraviolet band, a second band-pass filter that transmits light in the visible light band, and a third band-pass filter that transmits light in the infrared light band, and a welding visualization system characterized by this.

2. The camera unit has a wavelength conversion unit that converts light in the ultraviolet band into light in the visible light band; The welding visualization system according to claim 1, wherein the wavelength conversion unit converts the transmitted light of the first band-pass filter into visible light, and the image sensor performs imaging.

3. The welding visualization system according to claim 1, further comprising a filter control unit that sequentially switches the first band-pass filter, the second band-pass filter, and the third band-pass filter.

4. A plurality of camera units each including a band-pass filter and an image sensor corresponding to each of the band-pass filters; An image processing unit that synthesizes the images captured by the plurality of camera units; A display unit that displays the image synthesized by the image processing unit; comprising: The plurality of camera units are: A first camera unit including a first band-pass filter that transmits light in the ultraviolet band and a first image sensor; A second camera unit including a second band-pass filter that transmits light in the visible light band and a second image sensor; A third camera unit including a third band-pass filter that transmits light in the infrared light band and a third image sensor, and a welding visualization system characterized by this.

5. The first camera unit has a wavelength conversion unit that converts light in the ultraviolet band into light in the visible light band; The welding visualization system according to claim 4, wherein the wavelength conversion unit converts the transmitted light of the first band-pass filter into visible light, and the first image sensor performs imaging.

6. The welding visualization system according to claim 4 or 5, wherein the display unit displays the images captured by the plurality of camera units in real time.

7. The welding visualization system according to any one of claims 1 to 6, wherein the image processing unit binarizes the image with a predetermined threshold value and weights the data values of the binarized pixels.

8. A welding mask having the welding visualization system according to any one of claims 1 to 7.

Images