Weft detection device for looms

Abstract

The present invention provides a weft detection device for a loom that can easily identify the weft thread from images obtained by camera photography. [Solution] The weft detection device 20 is used in a loom 10 that weaves a fabric C consisting of weft yarn Y and warp yarn T by reeding weft yarn Y, which is inserted weft into the opening Ta of the warp yarn T in the left-right direction A1 of the loom 10, with a reed 15. The weft detection device 20 comprises an illumination unit 21 and a camera 22. The illumination unit 21 irradiates light onto the warp yarn T and the weft yarn Y. The illumination unit 21 irradiates light onto the weft yarn Y while interposing the warp yarn T between the illumination unit 21 and the weft yarn Y. The camera 22 photographs the weft yarn Y while interposing the warp yarn T and the weft yarn Y between the camera 22 and the illumination unit 21.

Description

Technical Field

[0001] The present invention relates to a weft yarn detection device for a loom.

Background Art

[0002] There is known a weft yarn detection device for a loom that detects the state of a weft yarn based on an image obtained by photographing with a camera. For example, a monitoring device which is a weft yarn detection device for a loom described in Patent Document 1 has a camera device and an irradiation device which is an irradiation unit. The camera device and the irradiation device are fixed to a frame forming a reed frame. The camera device photographs the weft yarn through a plurality of warp yarns. The irradiation device irradiates light along the direction from the camera device toward the weft yarn and the warp yarn. The monitoring device monitors the warp yarns and the weft yarns using the image data generated by the camera device.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When light is irradiated along the direction from the camera toward the weft yarn and the warp yarn, the camera photographs a region including the light reflected by the warp yarn. In this case, depending on the color of the warp yarn and the density of the warp yarn in the region to be photographed, it may be difficult to identify the weft yarn in the image obtained by photographing with the camera.

Means for Solving the Problems

[0005] The weft detection device for a loom that solves the above problems is used in a loom that weaves a fabric consisting of weft threads and warp threads by beating weft threads inserted weft in the left-right direction of the loom into the openings of the warp threads with a reed, and comprises an irradiation unit that irradiates light onto the warp threads and weft threads, wherein the irradiation unit irradiates the light onto the weft threads while interposing the warp threads between the irradiation unit and the weft threads, and a camera that photographs the weft threads while interposing the warp threads and weft threads between the irradiation unit and the weft threads.

[0006] According to this method, the camera photographs the weft threads located between the illuminating unit and the warp threads. Therefore, the camera photographs the weft threads with the light illuminated by the illuminating unit and the light transmitted through the warp and weft threads as the background. For example, compared to the case where light is illuminated from the illuminating unit in the direction from the camera toward the weft threads, the contrast between the weft threads and the background, which includes the light transmitted through the weft threads, is strengthened in the captured image. In other words, the camera can photograph the weft threads while emphasizing the boundary between the weft threads and the background. As a result, the weft threads can be easily identified from the image obtained by the camera.

[0007] In a weft detection device for a loom, it is preferable to include an image processing unit that processes images captured by the camera, and the image processing unit generates a frequency display image by performing a Fourier transform on the captured image, masks the region related to the warp threads in the frequency display image, and generates a processed image with enhanced representation of the weft threads by performing an inverse Fourier transform on the masked frequency display image.

[0008] According to this, the warp component removal unit filters out the warp-related displays from the captured image, thereby generating a processed image in which the weft threads are relatively emphasized relative to the warp threads in the captured image. In other words, by including a warp component removal unit, the weft detection device of a loom can easily identify the weft threads from the processed image obtained by image processing of the captured image.

[0009] In a weft detection device for a loom, the image processing unit may include a weft component enhancement unit that extracts a boundary extending along the weft in the captured image, between the weft and a portion of the captured image that is different from the weft, and generates a processed image in which the boundary is emphasized in the captured image.

[0010] According to this, the weft component enhancement unit extracts the boundary between the weft and parts other than the weft from the captured image, and generates a processed image in which the extracted boundary is enhanced in the captured image. As a result, the flight position of the weft and the shape of the flying weft can be easily determined from the processed image obtained by image processing the captured image. In other words, by including a weft component enhancement unit in the weft detection device of a loom, it is possible to easily understand the state of the flying weft.

[0011] In a weft detection device for a loom, the weft component enhancement unit may extract the boundary using a Gabor filter. The weft component enhancement unit extracts boundaries using a Gabor filter, enabling accurate boundary extraction even when, for example, the weft in the captured image meanders relative to its direction of flight. In other words, the weft detection device for a loom can extract the boundaries of the weft in the captured image with greater accuracy by using a Gabor filter for boundary extraction by the weft component enhancement unit.

[0012] In a weft detection device for a loom, the device is provided with an opening device that opens the warp threads and is positioned in the front-to-back direction of the loom, with one of the irradiation unit and the camera positioned between the opening device and the reed in the front-to-back direction, and the other of the irradiation unit and the camera positioned in front of the reed.

[0013] According to this design, the light emitted by the illumination unit is not blocked by the aperture device, but passes through the weft thread and reaches the camera. As a result, compared to, for example, a case where the aperture device is interposed between the illumination unit and the camera, the camera can capture the weft thread while emphasizing the boundary between the weft thread and the background.

[0014] In a weft thread detection device for a loom, it is preferable to further include a display unit that displays a processed image in which the display related to the weft thread is emphasized by the warp thread component removal unit, or a processed image in which the boundary is emphasized by the weft thread component emphasis unit.

[0015] According to this, a user who manages the operation of the loom can easily grasp the state of the weft thread from the processed image displayed on the display unit.

Effects of the Invention

[0016] According to the present invention, the weft thread can be easily identified from an image obtained by photographing with a camera.

Brief Description of the Drawings

[0017] [ [Figure 1] FIG. 1 is a plan view showing a loom and a weft thread detection device. [Figure 2] FIG. 2 is a side view showing a loom and a weft thread detection device. [Figure 3] FIG. 3 is a block diagram showing a weft thread detection device. [Figure 4] FIG. 4 is a view showing a photographed image. [Figure 5] FIG. 5 is a view showing a frequency display image. [Figure 6] FIG. 6 is a view showing a masked frequency display image. [Figure 7] FIG. 7 is a view showing a processed image generated by a warp thread component removal unit. [Figure 8] FIG. 8 is a view showing a processed image generated by a weft thread component emphasis unit. [Figure 9] FIG. 9 is a view showing a processed image generated by a contour extraction unit.

Modes for Carrying Out the Invention

[0018] Hereinafter, an embodiment of a weft detector for a loom will be described. The weft detector for a loom is used in a loom. In the following description, the weft detector for a loom is simply referred to as a "weft detector". In this embodiment, the loom is an air jet loom.

[0019] <loom> As shown in FIGS. 1 and 2, the loom 10 includes a side frame 11 as a frame, a supply roll 12, a shedding device 13, a weft insertion device 14, a reed 15, and a weft detector 20.

[0020] The frame of the loom 10 is a part of the loom that does not operate during reed beating. The loom 10 includes a pair of side frames 11. The pair of side frames 11 are arranged at both ends in the left - right direction A1 of the loom 10. Each side frame 11 extends in the front - rear direction A2 of the loom 10. On the side frame 11 arranged on the right side of the loom 10 among the pair of side frames 11, two brackets 11a are attached. The two brackets 11a are arranged in the front - rear direction A2 of the loom 10. Each bracket 11a is attached to the right - hand side frame 11 such that the base end is connected to the side frame 11 and the tip end is located between the pair of side frames 11. The bracket 11a is, for example, a magnet arm.

[0021] In the left - right direction A1 of the loom 10, a plurality of warp threads T are arranged. The plurality of warp threads T extend in the front - rear direction A2 of the loom 10. The supply roll 12 is provided at the rear part of the loom 10. A plurality of warp threads T are wound around the supply roll 12. The plurality of warp threads T are supplied forward from the supply roll 12. [[ID=??]] [[ID=??]]

[0022] [[ID=??]] The opening device 13 is provided on the loom 10. The opening device 13 comprises, for example, two heddle frames 13a. The two heddle frames 13a are arranged in the front-to-back direction A2. Each heddle frame 13a is provided with multiple heddles 13b as shown in Figure 2. Note that in Figure 2, only one heddle 13b is shown for each heddle frame 13a. The multiple heddles 13b on each heddle frame 13a are arranged in the left-to-right direction A1. Of the multiple warp threads T, some warp threads T are inserted through the heddles 13b provided on one heddle frame 13a, while other warp threads T are inserted through the heddles 13b provided on the other heddle frame 13a.

[0023] The opening device 13 opens the warp threads T. The opening device 13 reciprocates each heddle frame 13a in the vertical direction of the loom 10, thereby causing each warp thread T to reciprocate. When the opening device 13 moves one heddle frame 13a upward, it moves the other heddle frame 13a downward. As a result, the multiple warp threads T form an opening Ta as some warp threads T and other warp threads T are aligned in the vertical direction. In this way, the warp threads T are opened by the reciprocating motion of the heddle frames 13a by the opening device 13. The opening Ta extends in the left-right direction A1.

[0024] The weft insertion device 14 is installed on the loom 10. The weft insertion device 14 comprises a main nozzle 14a and a plurality of sub-nozzles 14b. The main nozzle 14a is installed on the left side of the loom 10 in the left-right direction A1. The plurality of sub-nozzles 14b are arranged in the left-right direction A1. The main nozzle 14a inserts the weft yarn Y into the opening Ta of the warp yarn T shown in Figure 2 by injecting air in the left-right direction A1 from the left side of the loom 10 toward the right side. The plurality of sub-nozzles 14b assist the flight of the weft yarn Y in the left-right direction A1 by injecting air onto the weft yarn Y inserted into the opening Ta.

[0025] The reed 15 is positioned between the opening device 13 and the multiple sub-nozzles 14b in the front-to-back direction A2. In other words, the opening device 13 is located in the same position as the reed 15 in the front-to-back direction A2 of the loom 10. The reed 15 is positioned to the right of the main nozzle 14a in the left-to-right direction A1.

[0026] The reed 15 has multiple reed blades 16. The multiple reed blades 16 are arranged in the left-right direction A1. The warp threads T pass between adjacent reed blades 16 in the left-right direction A1. As shown in Figure 2, a recess 16a is provided on the front surface of each reed 16. The reed 15 has a weft flight passage 15a. The weft flight passage 15a is formed by a plurality of recesses 16a connected in the left-right direction A1. The weft insertion device 14 shoots the weft Y into the weft flight passage 15a located inside the opening Ta. As a result, the inserted weft Y flies in the left-right direction A1 through the weft flight passage 15a inside the opening Ta.

[0027] The loom 10 is equipped with a slay 17. The slay 17 extends in the left-right direction A1. The slay 17 is attached to the side frame 11 via a locking shaft (not shown). (Not shown) The locking shaft is connected to a pair of side frames 11 at both ends. The locking shaft is rotatably supported relative to the side frame 11. The slay 17 can reciprocate in the front-rear direction A2 relative to the side frame 11 by the rotation of the locking shaft.

[0028] The slay 17 has a reed 15, a main nozzle 14a, and several sub-nozzles 14b fixed to it. The reed 15, the main nozzle 14a, and the several sub-nozzles 14b reciprocate in the forward / backward direction A2 of the loom 10 by the slay 17.

[0029] The reed 15 moves forward of the loom 10 by the sleigh 17, thereby beating the weft yarn Y that has been inserted into the opening Ta of the warp yarn T. In other words, the loom 10 beats the weft yarn Y that has been inserted in the left-right direction A1 relative to the opening Ta of the warp yarn T. The loom 10 weaves a fabric C consisting of weft yarn Y and warp yarn T by beating the reed. The woven fabric C is located in front of the sleigh 17.

[0030] <Weft detection device> As shown in Figure 3, the weft detection device 20 includes an illumination unit 21, a camera 22, a display unit 23, and an image processing unit 40.

[0031] As shown in Figures 1 and 2, the illumination unit 21 is installed between the opening device 13 and the reed 15 in the front-rear direction A2. The illumination unit 21 is, for example, an LED light. The illumination unit 21 is fixed to the side frame 11 of the loom 10. In other words, the illumination unit 21 is fixed to the part of the loom 10 that does not move during reed beating. Therefore, the illumination unit 21 does not move during reed beating. The illumination unit 21 is installed on the side frame 11 by the bracket 11a, which is located towards the rear of the loom 10, of the two brackets 11a. The illumination unit 21 is held at the tip of the bracket 11a. In other words, the illumination unit 21 is located between the pair of side frames 11 in the left-right direction A1 of the loom 10.

[0032] The irradiation unit 21 irradiates light onto the weft thread Y. More specifically, the irradiation unit 21 irradiates light onto the weft thread Y as it travels along the weft thread flight path 15a. In Figure 2, the area irradiated by the irradiation unit 21 is schematically shown by a dashed line.

[0033] The irradiation unit 21 is positioned in a location aligned with the woven fabric C in the front-to-back direction A2. As shown in Figure 1, the irradiation unit 21 is located in the right-hand portion of the loom 10 in the left-to-right direction A1. More specifically, the irradiation unit 21 is located near the end of the woven fabric C opposite to the main nozzle 14a in the left-to-right direction A1.

[0034] As shown in Figure 2, the irradiation unit 21 is positioned below the warp threads T in the vertical direction of the loom 10. More specifically, the irradiation unit 21 is fixed to the side frame 11 such that it is positioned below the range in which the warp threads T move vertically by the opening device 13. In other words, the irradiation unit 21 is fixed to the side frame 11 at a position below the weft thread passage 15a and behind the weft thread passage 15a. Therefore, the irradiation unit 21 irradiates the weft threads Y with light while the warp threads T are interposed between the irradiation unit 21 and the weft threads Y.

[0035] The irradiation unit 21 irradiates light onto the weft yarn Y from behind the weft yarn flight path 15a. In other words, the light irradiated from the irradiation unit 21 passes through the warp yarn T, which has been moved downward by the aperture device 13, and the reed 15 in that order, and then passes through the weft yarn Y and the warp yarn T, which has been moved upward by the aperture device 13, in that order. In this way, the light irradiated by the irradiation unit 21 passes through multiple warp yarns T, the reed 15, and the weft yarn Y before reaching the front of the loom 10. The irradiation unit 21 is configured to allow adjustment of the amount of light irradiated onto the weft yarn Y. The user managing the loom 10 adjusts the amount of light from the irradiation unit 21 according to the thickness of the woven fabric C to be produced.

[0036] Camera 22 is installed on the loom 10. Camera 22 is installed on the right side of the loom 10 in the left-right direction A1. More specifically, camera 22 is installed on the end of the woven fabric C opposite to the main nozzle 14a in the left-right direction A1.

[0037] Camera 22 has an image sensor. Examples of image sensors include CCD image sensors and CMOS image sensors. Camera 22 is installed on the loom 10 in front of the reed 15. Camera 22 is mounted on the side frame 11 by the bracket 11a, which is positioned towards the front of the loom 10, of the two brackets 11a. Camera 22 is held at the tip of the bracket 11a. In other words, camera 22 is fixed to a part of the loom 10 that does not move during reed beating. For this reason, camera 22 does not move during reed beating. Camera 22 is held by the bracket 11a at a position where it photographs the weft Y flying along the weft flight path 15a.

[0038] As described above, one of the illumination unit 21 and the camera 22 is installed between the aperture device 13 and the reed 15 in the front-rear direction A2, and the other of the illumination unit 21 and the camera 22 is positioned in front of the reed 15. In this embodiment, the illumination unit 21 is positioned between the aperture device 13 and the reed 15, while the camera 22 is positioned in front of the reed 15.

[0039] The camera 22 is positioned where it is illuminated by light from the illumination unit 21. As shown in Figure 1, the camera 22 is positioned in front of the illumination unit 21 in the front-to-back direction A2 when viewed from the top-to-bottom direction of the loom 10, and is positioned in front of the illumination unit 21. The camera 22 may also be positioned slightly to the right or slightly to the left of the illumination unit 21 in the left-to-right direction A1 of the loom 10.

[0040] As shown in Figure 2, the camera 22 is positioned so that it is illuminated by light that has passed through multiple warp threads T while passing through the weft thread Y. For this reason, the camera 22 is fixed to the side frame 11 at a position above and in front of the weft thread passage 15a. Furthermore, the camera 22 is positioned above the woven fabric C.

[0041] Camera 22 photographs the weft thread Y while the warp thread T and weft thread Y are interposed between Camera 22 and the illumination unit 21. Through this photography, Camera 22 acquires the captured image 30 shown in Figure 4 as image data.

[0042] As shown in Figure 4, the captured image 30 displays multiple warp threads T and weft threads Y. The captured image 30 is composed of image data of multiple warp threads T and weft threads Y flying along the weft thread flight path 15a. The captured image 30 is composed of color image data, but it is shown in grayscale in Figure 4. The camera 22 may acquire the captured image 30 as grayscale image data.

[0043] Hereafter, the direction in which the main axis of the weft thread Y extends in the captured image 30 will be referred to as the horizontal direction of the captured image 30, and the direction in which the main axis of the warp thread T extends in the captured image 30 will be referred to as the vertical direction of the captured image 30. In the captured image 30, the vertical direction is the direction perpendicular to the horizontal direction.

[0044] Camera 22 takes a photograph at the timing when a desired portion of the flying weft yarn Y is included in the camera's shooting area, based on a command from a control device (not shown). In this embodiment, the desired portion is the leading edge of the weft yarn Y. The desired portion may be any part of the weft yarn Y. The timing at which the desired portion is included in the camera's shooting area is determined, for example, based on the distance between the main nozzle 14a and camera 22 in the left-right direction A1 of the loom 10, and the time calculated from the flying speed of the weft yarn Y.

[0045] <Image Processing> As shown in Figure 2, the image processing unit 40 comprises a preprocessing unit 41, a warp component removal unit 42, a weft component enhancement unit 43, and a contour extraction unit 44.

[0046] The image processing unit 40 includes a processor and a memory unit. The processor may be, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), or a DSP (Digital Signal Processor). The memory unit includes RAM (Random Access Memory) and ROM (Read Only Memory). The memory unit stores program code or instructions configured to cause the processor to execute processing. The processor in the image processing unit 40 functions as a preprocessing unit 41, a warp component removal unit 42, a weft component enhancement unit 43, and a contour extraction unit 44 by executing the program code or instructions in the memory unit. The memory unit, i.e., the computer-readable medium, includes any available medium accessible by a general-purpose or dedicated computer. The image processing unit 40 may also be composed of hardware circuits such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array). The image processing unit 40, being a processing circuit, may include one or more processors operating according to a computer program, one or more hardware circuits such as an ASIC or FPGA, or a combination thereof.

[0047] The image processing unit 40 is connected to the camera 22. The image processing unit 40 receives the captured image 30 acquired by the camera 22 as image data. The image processing unit 40 then processes the input image data using the preprocessing unit 41, the warp component removal unit 42, the weft component enhancement unit 43, and the contour extraction unit 44, which will be described below. In this way, the image processing unit 40 processes the captured image 30 taken by the camera 22.

[0048] The image processing unit 40 may, for example, be connected to a control device (not shown) that controls the operation of the loom 10, and transmit information about the weft yarn Y identified in the captured image 30 to the control device. In this case, the control device controls the operation of the loom 10 based on the information about the weft yarn Y transmitted from the image processing unit 40. For example, if the control device detects an unacceptable degree of bending or meandering in the weft yarn Y identified by the image processing unit 40, it will perform a process to stop the operation of the loom 10. Alternatively, the image processing unit 40 may not be connected to the control device, but simply display the shape of the identified weft yarn Y using the display unit 23, which will be described later.

[0049] The image processing unit 40 generates a processed image 32, described later, using the warp component removal unit 42, the weft component enhancement unit 43, and the contour extraction unit 44, respectively. Hereafter, the processed image 32 generated by the warp component removal unit 42 will be referred to as the first processed image 321, the processed image 32 generated by the weft component enhancement unit 43 will be referred to as the second processed image 322, and the processed image 32 generated by the contour extraction unit 44 will be referred to as the third processed image 323.

[0050] <Pre-processing> The preprocessor 41 receives the captured image 30 as image data. The preprocessor 41 converts the captured image 30, which was acquired as color image data, to grayscale. However, if the camera 22 acquires the captured image 30 as grayscale image data, the preprocessor 41 does not need to perform this conversion.

[0051] The preprocessing unit 41 deletes a portion of the captured image 30 that does not contain the weft thread Y. As a result, the preprocessing unit 41 increases the proportion of the captured image 30 that is occupied by the area where the weft thread Y is displayed.

[0052] The preprocessing unit 41 outputs the image data on which the above processing has been performed. <Warp component removal section> The warp component removal unit 42 receives image data output from the preprocessing unit 41. In other words, the captured image 30 is input as image data to the warp component removal unit 42.

[0053] The warp component removal unit 42 performs smoothing on the input image data using a Gaussian filter. The warp component removal unit 42 reduces the noise contained in the captured image 30 using the Gaussian filter.

[0054] The warp component removal unit 42 performs processing on the image data of the input captured image 30 to enhance the display of the weft threads Y. By removing a portion of the frequency components related to multiple warp threads T from the captured image 30, the warp component removal unit 42 generates the first processed image 321 shown in Figure 7, in which the display of the weft threads Y is relatively enhanced relative to the warp threads T. The method by which the warp component removal unit 42 generates the first processed image 321 will be described in more detail below.

[0055] Figure 5 schematically shows the frequency display image 31 generated by the warp component removal unit 42. The warp component removal unit 42 generates the frequency display image 31 by performing a Fourier transform on the captured image 30. The frequency display image 31 is grayscale image data. The frequency display image 31 displays the amplitude spectrum related to the low-frequency components of the captured image 30 in the center. The frequency display image 31 also displays the amplitude spectrum related to the high-frequency components of the captured image 30 in the parts near the edges. In other words, the frequency display image 31 displays the distribution of the amplitude spectrum in frequency space related to the captured image 30. Each point on the frequency display image 31 corresponds to a frequency component contained in the captured image 30.

[0056] The frequency display image 31 shows the magnitude of the amplitude spectrum for each frequency component using shades of gray. The area of ​​the frequency display image 31 corresponding to the frequency component with the largest amplitude spectrum is shown in the lightest shade of gray. The area of ​​the frequency display image 31 corresponding to the frequency component with the smallest amplitude spectrum is shown in the darkest shade of gray. In other words, the frequency display image 31 shows the parts of the frequency display image corresponding to larger amplitude components in lighter shades of gray.

[0057] The frequency display image 31 is simplified by using a first region R1, which is the lightest gray; a second region R2, which is a darker gray than the first region R1; and a third region R3, which is a darker gray than the second region R2 and the darkest gray. In the unsimplified frequency display image 31, the gray density changes continuously according to the grayscale gradation between the first region R1 and the second region R2, and between the second region R2 and the third region R3. The first region R1 represents the region with the largest amplitude spectrum, and the third region R3 represents the region with the smallest amplitude spectrum.

[0058] In Figure 5, two orthogonal axes at the center of the frequency display image 31 are superimposed on the frequency display image 31. Hereafter, one axis of the frequency display image 31 will be referred to as the first axis 311, and the other axis as the second axis 312. In Figure 5, the first axis 311 extends horizontally, and the second axis 312 extends vertically. The intersection of the first axis 311 and the second axis 312 is denoted as the origin O. The intensity of each point on the first axis 311 indicates the magnitude of the amplitude spectrum of the frequency components related to the horizontally repeating pattern in the captured image 30. The intensity of each point on the second axis 312 indicates the magnitude of the amplitude spectrum of the frequency components related to the vertically repeating pattern in the captured image 30.

[0059] Figure 6 schematically shows a frequency display image 31 in which the region containing frequency components related to warp threads T has been masked by the warp component removal unit 42. The warp component removal unit 42 masks the region related to warp threads T in the frequency display image 31. Hereafter, the region related to warp threads T will be referred to as the masked region M.

[0060] More specifically, the mask region M is the portion of the frequency display image 31 excluding the vicinity of the origin O in the direction in which the first axis 311 extends. There are two mask regions M in the frequency display image 31. The mask region M contains frequency components related to a pattern that is repeated horizontally in the captured image 30. In other words, the warp component removal unit 42 masks the region of the frequency display image 31 that contains frequency components related to the pattern that is repeated horizontally in the captured image 30. This pattern in the captured image 30 is formed by warp threads T.

[0061] Figure 7 shows the first processed image 321 generated by the warp component removal unit 42. The first processed image 321 is generated by the warp component removal unit 42 performing an inverse Fourier transform on the frequency display image 31 in which the mask region M is masked. By performing an inverse Fourier transform on the frequency display image 31 in which the mask region M is masked, a processed image 32 is obtained in which the horizontally repeating pattern formed by the warp threads T is removed. In other words, the warp component removal unit 42 generates a processed image 32 in which the representation related to the weft threads Y is emphasized by performing an inverse Fourier transform on the masked frequency display image 31. More specifically, the warp component removal unit 42 generates the first processed image 321 in which the representation related to the weft threads Y is relatively emphasized compared to the representation related to the warp threads T by performing an inverse Fourier transform on the masked frequency display image 31.

[0062] The warp component removal unit 42 outputs image data relating to the first processed image 321. <Weft component emphasis section> The weft component enhancement unit 43 receives image data output from the warp component removal unit 42. In other words, the first processed image 321 is input as image data to the weft component enhancement unit 43.

[0063] The weft component enhancement unit 43 extracts the boundary L between the weft Y and the portion of the captured image 30 that is not the weft Y. The weft component enhancement unit 43 extracts the boundary L in the captured image 30 by performing processing on the first processed image 321. The boundary L extends along the weft Y in the captured image 30. More specifically, the boundary L is a curved shape that extends along the weft Y and the portion of the captured image 30 that is not the weft Y. The weft component enhancement unit 43 generates a processed image 32 in which the boundary L in the captured image 30 is enhanced. The weft component enhancement unit 43 enhances the boundary L by, for example, increasing the difference in gray intensity between the pixel corresponding to the boundary L in the captured image 30 and the adjacent pixel that does not correspond to the weft Y.

[0064] Figure 8 shows the second processed image 322 generated by the weft component enhancement unit 43. The second processed image 322 enhances the display of the weft Y by emphasizing the boundary L extracted by the weft component enhancement unit 43. In Figure 8, the boundary L is shown by two dashed lines. Note that in Figure 8, the boundary L is shown slightly separated from the weft Y and exaggerated in order to show the position and shape of the boundary L on the second processed image 322. The weft component enhancement unit 43 extracts the boundary L related to the weft Y from the input image data by applying a Gabor filter to the image data. In other words, the weft component enhancement unit 43 extracts the boundary L using a Gabor filter. In this embodiment, the parameters of the Gabor filter are set so that it can extract lines extending horizontally in the captured image 30.

[0065] The weft component enhancement unit 43 outputs the image data generated by the above processing. <Contour extraction section> The contour extraction unit 44 receives image data output from the weft component enhancement unit 43. In other words, the contour extraction unit 44 receives the second processed image 322 as image data.

[0066] The contour extraction unit 44 performs smoothing on the input image data using a Gaussian filter. The contour extraction unit 44 reduces the noise contained in the second processed image 322 using the Gaussian filter.

[0067] The contour extraction unit 44 extracts edges extending along the boundary L in the second processed image 322 as multiple curves extending along the boundary L. The contour extraction unit 44 extracts the boundary line, for example, using the Canny method. Note that the boundary line extraction by the contour extraction unit 44 may be performed using edge detection methods other than the Canny method, such as the Sobel method or the Previtt method.

[0068] The contour extraction unit 44 identifies closed curves connecting multiple edges by performing a closing process on the image data including the extracted edges. The contour extraction unit 44 identifies the region enclosed by the identified closed curves as the weft region. The contour extraction unit 44 generates a third processed image 323 by superimposing the weft region onto the captured image 30.

[0069] Figure 9 shows the third processed image 323. In the third processed image 323, the closed curve identified by the contour extraction unit 44 is shown by a dashed line and superimposed on the captured image 30. Note that the area of ​​the closed curve shown in Figure 9 is exaggerated compared to reality for ease of illustration. The region enclosed by the dashed line in Figure 9 is the weft region of this embodiment.

[0070] The contour extraction unit 44 outputs the image data generated by the above process. <Display section> The display unit 23 is a display connected to the image processing unit 40. Image data is input to the display unit 23 from the image processing unit 40. The display unit 23 is configured to display the input image data.

[0071] The display unit 23 displays the processed image 32. The display unit 23 displays either the first processed image 321 or the second processed image 322. In other words, the display unit 23 displays either the processed image 32 in which the representation related to the weft Y is emphasized by the warp component removal unit 42, or the processed image 32 in which the boundary L is emphasized by the weft component emphasis unit 43. In this embodiment, the display unit 23 displays the second processed image 322. In other words, the weft detection device 20 displays the second processed image 322 shown in Figure 8 on the display unit 23.

[0072] Furthermore, the display unit 23 displays the third processed image 323. The weft detection device 20 of this embodiment displays the processed images 32 shown in Figures 8 and 9 side by side on the display unit 23. In Figure 9, the weft region identified by the contour extraction unit 44 is displayed wider than the portion of the weft Y that has not been identified as a weft region. When the display unit 23 overlays the weft region on the captured image 30, the weft region may be colored differently from the other areas of the captured image 30.

[0073] [Effects of this embodiment] The effects of this embodiment will be explained along with their operation. (1) Camera 22 photographs the weft thread Y located between itself and the illumination unit 21. For this reason, camera 22 photographs the weft thread Y with the light that is illuminated by the illumination unit 21 and has passed through the weft thread Y and warp thread T as the background. For example, consider the case where light is illuminated from the illumination unit 21 in the direction from camera 22 toward the weft thread Y. In this case, camera 22 photographs the weft thread Y with the light reflected by the weft thread Y and warp thread T as the background. Compared to this case, by camera 22 photographing the weft thread Y with the light that has passed through the weft thread Y and warp thread T as the background, the contrast between the weft thread Y and the parts that are not the weft thread Y in the captured image 30 is strengthened. In other words, camera 22 can photograph the weft thread Y while emphasizing the boundary L between the weft thread Y and the background.

[0074] (2) The light emitted by the illumination unit 21 is not obstructed by the aperture device 13, and after passing through the weft Y, it reaches the camera 22. As a result, for example, compared to the case where the aperture device 13 is interposed between the illumination unit 21 and the camera 22, the camera 22 can photograph the weft Y while emphasizing the boundary L between the weft Y and the background.

[0075] (3) The camera 22 and the illumination unit 21 are mounted on the side frame 11 of the loom 10. Therefore, compared to the case where the camera 22 and the illumination unit 21 are mounted on the reed 15, for example, movement of the camera 22 and the illumination unit 21 during reed beating is suppressed. Accordingly, the weft detection device 20 of the loom 10 can reduce the influence of the loom 10's movement on the captured image 30 by fixing the illumination unit 21 and the camera 22 to the side frame 11 of the loom 10.

[0076] (4) The warp component removal unit 42 generates a processed image 32 in which the weft Y in the captured image 30 is relatively emphasized with respect to the warp T. In other words, the weft detection device 20 of the loom 10 is equipped with a warp component removal unit 42 so that the weft Y can be easily identified from the processed image 32 obtained by image processing the captured image 30.

[0077] (5) The weft component enhancement unit 43 extracts the boundary L between the weft Y and the portion that is different from the weft Y from the captured image 30, and generates a processed image 32 in which the extracted boundary L is enhanced in the captured image 30. This makes it easy to understand the flight position of the weft Y and the shape of the flight weft Y from the processed image 32 obtained by image processing the captured image 30. In other words, by including the weft component enhancement unit 43 in the weft detection device 20 of the loom 10, it is possible to easily understand the state of the flight weft Y.

[0078] (6) The weft component enhancement unit 43 extracts the boundary L using a Gabor filter, so that even if the weft Y in the captured image 30 is meandering with respect to the direction of flight of the weft Y, the boundary L can be extracted with high accuracy. In other words, the weft detection device 20 of the loom 10 can extract the boundary L of the weft Y in the captured image 30 with higher accuracy by using a Gabor filter for the extraction of the boundary L by the weft component enhancement unit 43.

[0079] (7) The processed image 32 generated by the image processing unit 40 is displayed by the display unit 23. This allows the user who manages the operation of the loom 10 to easily understand the state of the weft yarn Y from the processed image 32 displayed on the display unit 23.

[0080] (8) The irradiation unit 21 is configured to allow adjustment of the light intensity. This makes it possible to reduce the light intensity according to the thickness of the fabric C, even when weaving a thin woven fabric C, thereby suppressing a decrease in the identification performance of the weft yarn Y due to the amount of light.

[0081] (9) The image processing unit 40 processes the captured image 30 in which the weft Y is emphasized by light transmitted through the weft Y and warp T. For example, consider the case where the captured image 30 is photographed with the weft Y against a background of light reflected from the weft Y and warp T. Compared to this case, the image processing unit 40 can perform image processing of the captured image 30 with greater accuracy.

[0082] [Example of changes] The above embodiment can be implemented with the following modifications. The above embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0083] ○ The weft detection device 20 does not need to have a display unit 23. In this case, the weft detection device 20 may output a signal to a control device (not shown) to control the operation of the loom 10 based on the processed image 32 generated by the image processing unit 40, without displaying information about the weft Y to the user.

[0084] ○ The display unit 23 does not have to display the second processed image 322. In this case, the display unit 23 displays the first processed image 321. Alternatively, the display unit 23 may display the first processed image 321 and the second processed image 322 side by side. In short, the display unit 23 only needs to display at least one of the first processed image 321 and the second processed image 322.

[0085] ○ The display unit 23 does not have to display the third processed image 323. For example, the display unit 23 may display only one of the first processed image 321 and the second processed image 322.

[0086] ○ The weft component enhancement unit 43 does not have to be a Gabor filter. The weft component enhancement unit 43 may, for example, extract the boundary L by performing a Hough transform on the input image data. In other words, the shape of the extracted boundary L does not have to be curved. Also, the weft component enhancement unit 43 does not have to extract the boundary L in a linear form. In short, the weft component enhancement unit 43 only needs to be able to extract a set of pixels corresponding to the boundary L.

[0087] ○ The image processing unit 40 does not necessarily have to include a weft component enhancement unit 43. In this case, the image processing unit 40 may, for example, generate a third processed image 323 from the image data relating to the first processed image 321 generated by the warp component removal unit 42 using a contour extraction unit 44.

[0088] ○ The warp component removal section 42 does not necessarily have to perform smoothing using a Gaussian filter. For example, the warp component removal section 42 may perform smoothing using a median filter instead of a Gaussian filter.

[0089] ○ The warp component removal unit 42 does not need to perform smoothing on the input image data. ○ The image processing unit 40 does not necessarily have to include a warp component removal unit 42. In this case, the image processing unit 40 may generate a second processed image 322 by, for example, processing the captured image 30 with a weft component enhancement unit 43.

[0090] ○ In the image processing unit 40, the order in which the warp component removal unit 42 and the weft component enhancement unit 43 are executed is not limited to the embodiment. In other words, the warp component removal unit 42 may perform processing on the image data output by the weft component enhancement unit 43.

[0091] ○ The image processing unit 40 does not necessarily have to include the preprocessing unit 41. For example, the camera 22 may be pre-configured to capture only the vicinity of the weft thread Y. Also, for example, the camera 22 may be pre-configured to acquire the captured image 30 as grayscale image data.

[0092] ○ The weft detection device 20 does not necessarily have to include an image processing unit 40. For example, the weft detection device 20 may display the captured image 30 obtained by the camera 22 on the display unit 23. Alternatively, the weft detection device 20 may output image data related to the captured image 30 to a storage medium provided outside the loom 10.

[0093] The illumination unit 21 and the camera 22 do not necessarily have to be fixed to the side frame 11 of the loom 10. For example, the illumination unit 21 and the camera 22 may be fixed to a frame of the loom 10 other than the side frame 11.

[0094] ○ The illumination unit 21 does not have to be installed on the side frame 11 of the loom 10 so as to be between the opening device 13 and the reed 15 in the front-rear direction A2. Also, the camera 22 does not have to be installed on the side frame 11 of the loom 10 in front of the reed 15. For example, in the weft detection device 20, the illumination unit 21 may be installed on the slay 17 and irradiate light upwards, and the camera 22 may be installed on the upper end of the reed 15 and photograph downwards. In this case, the weft Y will travel at a position above the illumination unit 21 and below the camera 22.

[0095] ○ In the front-to-back direction A2 of the loom 10, the order in which the illumination unit 21 and the camera 22 are arranged is not limited to that of the embodiment. For example, the camera 22 may be installed on the bracket 11a where the illumination unit 21 was installed in the embodiment, and the illumination unit 21 may be installed on the bracket 11a where the camera 22 was installed in the embodiment.

[0096] [Note] The technical concepts that can be understood from the above embodiments and modified examples are described below. <Note 1> The irradiation unit is configured to allow adjustment of the amount of light irradiated onto the weft thread, and is a weft thread detection device for a loom.

[0097] <Note 2> A weft detection device for a loom, comprising an image processing unit for processing images captured by the camera, the image processing unit extracts a boundary in the captured image that extends along the weft, between the weft and a portion of the captured image that is different from the weft, and a weft component enhancement unit that generates a processed image in which the boundary is emphasized in the captured image. [Explanation of symbols]

[0098] 10...Loom, 13...Opening device, 15...Reed, 20...Weft detection device, 21...Irradiation unit, 22...Camera, 23...Display unit, 30...Captured image, 31...Frequency display image, 32...Processed image, 40...Image processing unit, 42...Warp component removal unit, 43...Weft component enhancement unit, A1...Left-right direction, A2...Front-back direction, C...Woven fabric, L...Boundary, T...Warp, Ta...Opening, Y...Weft.

Claims

1. Used in a loom that weaves a fabric consisting of the weft threads and warp threads by beating the weft threads, which are inserted into the openings of the warp threads in the left-right direction of the loom, with a reed. An irradiation unit that irradiates light onto the warp threads and the weft threads, wherein the irradiation unit irradiates light onto the weft threads while interposing the warp threads between the irradiation unit and the weft threads, A weft detection device for a loom, comprising a camera that photographs the weft while interposing the warp and weft threads between itself and the irradiation unit.

2. The system includes an image processing unit that processes the captured image taken by the aforementioned camera, The weft detection device for a loom according to claim 1, wherein the image processing unit generates a frequency display image by performing a Fourier transform on the captured image, masks the region relating to the warp threads in the frequency display image, and generates a processed image with enhanced representation of the weft threads by performing an inverse Fourier transform on the masked frequency display image.

3. The weft detection device for a loom according to claim 2, wherein the image processing unit includes a weft component enhancement unit that extracts a boundary extending along the weft in the captured image, between the weft and a portion of the captured image that is different from the weft, and generates a processed image in which the boundary is emphasized in the captured image.

4. The weft component enhancement unit extracts the boundary using a Gabor filter, as described in claim 3, for the weft detection device for a loom.

5. The loom is provided with an opening device that is positioned in the front-to-back direction of the loom, adjacent to the reed, and opens the warp threads. The irradiation unit and the camera are installed between the aperture device and the reed in the front-rear direction. The weft detection device for a loom according to any one of claims 1 to 4, wherein the other of the irradiation unit and the camera is installed in front of the reed.

6. The weft detection device for a loom according to claim 3 or claim 4, further comprising a display unit that displays a processed image in which the representation relating to the weft is emphasized by the warp component removal unit, or a processed image in which the boundary is emphasized by the weft component emphasis unit.

Images