Visual inspection system for foreign matter on the surface of seaweed

Abstract

To provide a visual inspection system of a foreign substance on the surface of laver which easily distinguishes and finds a foreign substance regardless of discoloration and unevenness, and simply and easily achieves the distinguishment and finding.SOLUTION: A visual inspection system S relates an auxiliary system used for visual inspection of a foreign substance, in work of removing a foreign matter attached to laver B. The visual inspection system S includes a light source 1, a light source side polarizing plate 2, and a visual inspection side polarizing plate 3. The light source 1 irradiates the laver B with light. The light source side polarizing plate 2 is annexed to the light source 1, and permeates irradiation only light of a constant polarization surface, out of the irradiation light L of the light source 1. The visual inspection side polarizing plate 3 is provided on the visual inspection side, has a polarization surface shifted by 90 degrees, and receives the irradiation light L of the light source 1 through the light source side polarizing plate 2 as reflection light R through the laver B. Therefore, foreign substance inspection is performed by visual inspection, on the basis of light permeation and light shielding of the visual inspection side polarizing plate 3. The light source 1 is arranged on the upper part on the visual inspection side, is formed into a line shape, and irradiates the laver B with light at an acute angle from one oblique direction with an angle.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a visual inspection system for foreign matter on the surface of laver, that is, to an auxiliary system used for visually inspecting foreign matter when removing foreign matter attached to laver. [Background technology]

[0002] 《Technical background》 On the nori (dried nori) production line, after the pre-processing lines of picking raw nori, washing with water, papering, dehydrating, and drying, the nori goes through post-processing lines of sorting for foreign objects, counting and accumulating, folding, and bundling before being produced and shipped. In the foreign matter sorting process, a foreign matter sorting machine sorts out seaweed B that has foreign matter A, such as various impurities and metals, attached to it, as shown in Figure 4 (1) and (2). After sorting, the seaweed B with foreign matter A attached is separated from the other good seaweed B, removed from the line, and collected in a defective bucket. After the incident, the seaweed was removed from the defective bucket and the foreign object A was removed from each piece by hand using a knife or other tool. The seaweed B from which the foreign object A had been removed was then returned to the line as a product.

[0003] Now, the work of removing such foreign object A is carried out while visually inspecting the seaweed B. Foreign object A is searched for, found, and its location determined by visual inspection, and foreign object A found during the visual inspection is then removed manually. However, large foreign objects A are already removed by a removal device that removes the raw seaweed before it is supplied to the production line. Therefore, most of the foreign objects A that are subjected to this removal process are small, and it is not easy to find them by visual inspection. Visual inspection of small foreign objects A is fraught with difficulties.

[0004] <<Prior Art>> In view of this situation, visual inspection systems have been developed in the past, that is, auxiliary systems used for visually inspecting foreign matter A during the work of removing foreign matter A. This system was based on the premise that the reflection characteristics of Nori B were almost total reflection, and was equipped with a light source, a light source side polarizing plate, and a viewing side polarizing plate. The light source illuminated Nori B from directly above. The light source side polarizing plate transmits only light with a certain polarization plane from the light source. The viewing side polarizing plate has a polarization plane shifted by 90 degrees, and receives the light from the light source as reflected light through Nori B. Therefore, if there is no foreign substance A, the light is blocked by the polarizing plate on the viewing side, and no light enters when viewed. In contrast, if foreign substance A is present, → the diffuse reflection from foreign substance A causes a shift in the polarization plane of the reflected light → so that the light is not blocked by the viewing-side polarizing plate → and → enters the image when viewed. Therefore, it is determined that foreign substance A is present. In this system, by giving brightness to foreign matter A in this way, visual inspection of foreign matter A was facilitated. [Prior art documents] [Patent documents]

[0005] An example of such a conventional technique is that shown in the following Non-Patent Document 1. [Non-Patent Document 1] "8. Inspection method for scratches and foreign matter in seaweed" on pages 291 to 293 of "Automation Technology for Visual Inspection" by Tadashi Nakajima, published by Techno System Co., Ltd., first published on January 6, 1995 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the following problems have been pointed out as issues with the conventional visual inspection system for foreign matter A on the surface of seaweed B described above. First, when the amount of nutrients in the seaweed B decreases, the color of the seaweed changes from black to light brown to gold, and then the color fades overall to C, as shown in Figure 4 (3). Furthermore, as shown in Figure 4 (4), unevenness D due to fuzzing occurs on the back surface of the nori B, although the degree of unevenness varies. Therefore, it has been pointed out that conventional visual inspection systems have a problem in that it is difficult to distinguish and detect foreign matter A in the case of seaweed B that has discoloration C and unevenness D. In particular, when the degree of discoloration C is severe or the degree of unevenness D is large, it can be difficult to distinguish and detect foreign matter A.

[0007] This will be explained in detail below. The unevenness D, like the foreign substance A, causes diffuse reflection in many directions. The discoloration C also reflects light not only in a predetermined direction but also in other directions. As a result, like the foreign substance A, a deviation occurs in the plane of polarization of the reflected light, and the light is not blocked by the viewing-side polarizing plate and enters the screen when viewed. In the conventional visual inspection system, the light source illuminated the seaweed B evenly from directly above in all directions, so in the case of seaweed B with discoloration C and unevenness D, the surface reflection was large and the polarization effect was reduced. That is, when visually inspected, as shown in the visual brightness distribution diagram in Figure 3 (2), the light and dark areas caused by the discoloration C and unevenness D of the seaweed B formed the overall background / backbone, and the number of light and dark areas was large and varied, and the brightness difference between the light and dark areas was also large, so the light and dark areas stood out and were easily noticed. Under these overall conditions, foreign matter A has the highest brightness due to diffuse reflection, but it is tiny and only a few in number are scattered around. Therefore, the inspection to find, discover, and identify foreign body A was not easy and took time. It was necessary to look over and observe the entire seaweed B and find the brightest spot, which also took time. In particular, depending on the degree of color fading C and the degree of unevenness D (fuzzing), it may be difficult to distinguish from foreign matter A. There is a risk of misdetection or failure to remove foreign matter A. In the past, such problems have been pointed out as issues.

[0008] About the present invention The visual inspection system for foreign matter on the surface of laver according to the present invention has been made in consideration of the above circumstances and to solve the problems of the prior art. The present invention aims to provide, first, a visual inspection system for foreign matter on the surface of seaweed that makes it easy to distinguish and detect foreign matter regardless of discoloration or unevenness of the seaweed, and second, that makes this possible simply and easily. [Means for solving the problem]

[0009] <<About each claim>> The technical means of the present invention for solving such problems are as follows, as set forth in the claims. Regarding claim 1, the following applies: The visual inspection system for foreign matter on the surface of laver according to claim 1 comprises: This auxiliary system is used for visually inspecting foreign matter adhering to the outer surface of laver during removal work, and includes a box whose side of the laver faces the viewer and is open, a light source, a light source-side polarizing plate, and a viewer-side polarizing plate provided in the box. The light source is a straight rod-shaped or line-shaped LED arranged outside and above the visible end of the nori seaweed, and illuminates the nori seaweed at an irradiation angle of 20 to 30 degrees toward the inside of the box, which is the back of the box, with respect to a perpendicular line extending from the top to the bottom of the box. the light source-side polarizing plate is attached to the light source and transmits only light of a certain polarization plane from the light source; The view-side polarizing plate is provided on the view side of the box body, and is inclined downward toward the outside of the box body at a set angle of 20 degrees to 45 degrees with respect to a perpendicular line extending from the top surface to the bottom surface of the box body, and its polarization plane is shifted by 90 degrees. Light emitted from the light source that has passed through the light-source-side polarizing plate is received as reflected light through the seaweed, and foreign matter inspection is performed visually based on the light transmission and light blocking of the view-side polarizing plate. When there is no foreign matter, the reflected light is blocked by the polarizing plate on the viewing side and does not pass through, so no light is incident upon viewing. If a foreign object is present, the plane of polarization of the reflected light is shifted due to diffuse reflection, and the reflected light is not blocked by the viewing-side polarizing plate but passes through, resulting in a light-entering state when viewed visually, which is determined to indicate the presence of a foreign object. It is characterized by:

[0010] Regarding claim 2, the following applies: The visual inspection system for foreign matter on the surface of laver according to claim 2 comprises: This auxiliary system is used for visual inspection of foreign matter adhering to the outer surface of laver during removal work, and includes a box whose side of the laver faces the viewer and is open, a light source provided in the box, a light source-side polarizing plate, and viewer-side polarized glasses. The light source is a straight rod-shaped or line-shaped LED arranged outside and above the visible end of the nori seaweed, and illuminates the nori seaweed at an irradiation angle of 20 to 30 degrees toward the inside of the box, which is the back of the box, with respect to a perpendicular line extending from the top to the bottom of the box. the light source-side polarizing plate is attached to the light source and transmits only light of a certain polarization plane from the light source; The viewer of the seaweed wears the viewer-side polarized glasses, and when worn, the polarization plane is shifted by 90 degrees. Light emitted from the light source that has passed through the light source-side polarizing plate is received as reflected light through the seaweed, and a foreign substance inspection is performed visually based on the light transmission and light blocking of the viewer-side polarized glasses. When there is no foreign matter, the reflected light is blocked by the polarized glasses on the viewing side and does not pass through, so no light enters when viewed visually. If a foreign object is present, the plane of polarization of the reflected light is shifted due to diffuse reflection, and the reflected light is not blocked by the polarized glasses on the viewing side but passes through, resulting in a light-entering state when viewed visually, which is determined to indicate the presence of a foreign object. It is characterized by: Regarding claim 3, the following applies: The visual inspection system for foreign matter on the surface of laver of claim 3 comprises the steps of claim 1 or 2, If the seaweed has discoloration or unevenness, the polarization plane of the reflected light will shift, and some of the reflected light will be transmitted without being blocked, resulting in light being incident when viewed visually. The aforementioned light source but The above setting Being an angle This reduces reflection, and the light is incident on the entire surface and the brightness of the incident light is low when visually inspected, so that foreign matter can be distinguished and found regardless of discoloration or unevenness.

[0011] Regarding claim 4, the following applies: The visual inspection system for foreign matter on the surface of laver of claim 4 comprises the steps of: The box has a seaweed stand on the bottom, which is inclined downward from the back side of the box to the viewing side.

[0012] <About the effects> The present invention comprises such means and is as follows: (1) The removal of foreign matter from seaweed is carried out through visual inspection, supplemented by the use of a visual inspection system. (2) In the visual inspection system, the light from the light source passes through the light source side polarizing plate, and light with a certain polarization plane is reflected by the seaweed and received as reflected light by the viewing side polarizing plate, whose polarization plane is shifted by 90 degrees. Thus, the presence or absence of foreign matter is determined and inspected based on whether the polarizing plate on the viewing side transmits or blocks light. Such a visual inspection system will be described in detail below. (3) First, if there is no foreign matter, the reflected light is blocked by the polarizing plate on the viewing side and does not pass through, so no light enters when viewed with the naked eye. This means that there is no foreign matter. (4) In contrast, if a foreign object is present, the diffuse reflection causes a shift in the polarization plane of the reflected light, and the reflected light is not blocked by the viewing-side polarizing plate but passes through, becoming incident upon visual inspection. This indicates the presence of a foreign object. (5) Now, if the seaweed has discoloration or unevenness, a shift in the polarization plane of the reflected light will occur, and some of the reflected light will pass through the polarizing plate on the viewing side without being blocked, resulting in light entering the viewing area. However, the reflection of discoloration and unevenness can be suppressed by adjusting the light source settings, and the light incident on the surface is uniform and the brightness is low when visually inspected. Therefore, foreign matter can be easily distinguished and detected regardless of discoloration or unevenness. This is explained in (6), (7), and (8) below. (6) Discoloration causes reflected light to be reflected not only in the intended direction but also in other directions, resulting in a slight deviation in the plane of polarization of the reflected light. Irregularities cause slight diffuse reflection in other directions, resulting in a slight deviation in the plane of polarization of the reflected light. Therefore, discoloration and irregularities appear as light entering the surface when viewed with the naked eye. (7) Therefore, in the present invention, the light source is linear and illuminates the seaweed at an acute angle from a diagonal direction above and outside the visible end of the seaweed. As a result, the surface reflection of the laver is suppressed to a low level, and the number of bright and dark areas is reduced when viewed visually, and the difference in brightness between the areas is also reduced. (8) The discoloration and unevenness form the overall background and backbone of the seaweed, but because the light intensity is low to begin with, the differences in brightness are not as noticeable as shown here. In contrast, foreign particles, although small in size, are the brightest and scattered, making them highly visible. This makes it easy to distinguish and detect foreign particles, regardless of discoloration or unevenness. [Effects of the Invention]

[0013] First effect First, it is easy to distinguish and detect foreign objects regardless of discoloration or unevenness of the seaweed. In the visual inspection system for foreign matter on the surface of seaweed according to the present invention, even if the seaweed has discoloration or unevenness, the reflection is kept low, thereby making the foreign matter visible and maintaining the polarization effect. In other words, when viewed visually, the number of light and dark areas and the difference in brightness between the discoloration and unevenness that make up the overall background / backbone of the seaweed are reduced, and the light and dark areas are also smaller. When viewed visually, there is little risk of the light and dark areas standing out and catching the eye, as in the prior art described above. In contrast, small but bright foreign particles scattered throughout the area stand out and become visible, making it easier to find, discover, and determine their location. By simply observing locally, rather than overlooking the entire area, it becomes possible to make a judgment and perform inspection in a short time. In particular, even in the case of laver with severe discoloration or unevenness, it is possible to distinguish and detect foreign matter regardless of these, eliminating the risk of missing or failing to remove foreign matter.

[0014] Second Effect Second, this is easy and straightforward to achieve. The visual inspection system for seaweed surface foreign matter of the present invention is characterized by the addition of a new configuration to a conventionally known system, i.e., a system equipped with a light source, a light source-side polarizing plate, and a viewing-side polarizing plate (see also non-patent document 1 listed in the prior art literature section). The light source is arranged above the viewing side, in a linear shape, and angled to illuminate from one oblique direction at an acute angle. With this simple configuration, foreign objects can be distinguished and detected regardless of discoloration or unevenness. In addition, if polarized glasses for the viewing side are used instead of the polarizing plate for the viewing side, the removal work can be performed without any hindrance and there is no reflection of the face or the like, which contributes to simplification. In this way, the effects of the present invention are remarkable and great, as all of the problems that existed in the prior art of this type are solved. [Brief explanation of the drawings]

[0015] [Figure 1] The following are cross-sectional side views of a visual inspection system for foreign matter on the surface of laver according to the present invention, which are provided for explaining an embodiment of the invention. Figure (1) shows Example 1, and Figure (2) shows Example 2. [Figure 2] FIG. 1 is a front view of a first embodiment of the present invention, illustrating an embodiment of the present invention. [Figure 3] 1A and 1B are explanatory diagrams of visual brightness distributions for explaining the embodiment of the present invention, in which (1) relates to the present invention and (2) relates to a conventional example. [Figure 4] To explain the seaweed with foreign matter attached, (1) is a plan view of the seaweed, (2) is an enlarged longitudinal cross section of the seaweed, (3) is a plan view of the discolored seaweed, and (4) is an enlarged longitudinal cross section of the seaweed with a fuzzy, uneven underside. DETAILED DESCRIPTION OF THE INVENTION

[0016] The present invention will be described in detail below with reference to the drawings of FIGS. 1 to 4 and Table 1. Overview of the Invention First, the outline of the present invention is as follows. The visual inspection system S for foreign matter A on the surface of seaweed B of the present invention relates to an auxiliary system used for visually inspecting foreign matter A when removing foreign matter A attached to the outer surface of seaweed B. The system includes a light source 1, a light source-side polarizing plate 2, and a viewing-side polarizing plate 3. The light source 1 irradiates the placed seaweed B. The light source-side polarizing plate 2 is attached to the light source 1 and transmits only light of a certain polarization plane out of the light L emitted from the light source 1. Viewing-side polarizing plate 3 is provided on the viewing side, with its polarization plane shifted by 90 degrees, and receives light L emitted from light source 1 that has passed through light source-side polarizing plate 2 as reflected light R via seaweed B. Thus, foreign matter inspection is performed visually based on the light transmission and light blocking of viewing-side polarizing plate 3 (see also Non-Patent Document 1). The present invention is characterized in that the light source 1 is arranged above the viewing side, is linear, and is set to irradiate the seaweed B at an acute angle from one oblique direction. The outline of the present invention is as above. The present invention will be described in further detail below.

[0017] [Table 1]

[0018] About Nori B First, the seaweed B will be described with reference to (1) and (2) in FIG. Nori B, which is harvested from the ocean and processed on a production line, is a roughly rectangular sheet measuring approximately 190 mm wide and 210 mm long. It contains a large amount of foreign matter A, including impurities and metals. That is, impurities such as pieces of vinyl, feathers, shells, paper, pieces of wood, sawdust, stone chips, sand, soil, fine stones, shrimp, insects, etc. are often found adhering as foreign matter A. Foreign matter A may also be chipped pieces, tiny pieces, wear particles, rust, fine powder, residue, etc. of iron, aluminum, copper, stainless steel, and other metals. The foreign substance A is attached to the outer surface of the laver B, i.e., the front and back surfaces of the laver B. When removing the foreign substance A, the back surface is turned upside down and used for the work (note that the term "surface" in the title of the invention of this application is used in a broad sense and has the same meaning as the "outer surface"). For details on the production line, foreign substance A sorting process, foreign substance A removal work, etc., please refer to the above mentioned technical background section. By the way, seaweed B is usually black, but when the nutrients in the sea are reduced in the fresh seaweed that is harvested, it fades to color C. The overall color changes from black to light brown (cardboard color) to gold. Furthermore, there is unevenness D on the backside of Nori B. Due to the paper-making process on the production line, unevenness D due to fuzzing occurs all over the surface, although the degree of unevenness varies. The above is the case for Nori B.

[0019] Visual Inspection System S The visual inspection system S of the present invention is used to visually inspect foreign matter A adhering to the outer surface of seaweed B during removal work of the foreign matter A. That is, it is used as an auxiliary tool during visual inspection of foreign matter A, and foreign matter A that is found, discovered, and located during visual inspection is manually removed by the inspector P each time. Thus, this visual inspection system S includes a light source 1, a light source side polarizing plate 2, and a viewer side polarizing plate 3, as shown in FIG. 1(1).

[0020] Visual inspection using the visual inspection system S is carried out using a box 4. The box 4 is open on the side facing the viewer P, and has a light source 1 located below the top of the interior and a plate stand 5 for seaweed B located above the bottom. The stand 5 is inclined downwards towards the viewer P to make it easier for the viewer P to remove the foreign matter A. Light source-side polarizing plate 2 is attached to the front side of light source 1. Viewer-side polarizing plate 3 is attached to the open side of box body 4 by a hinge or the like. The above is an overview of the visual inspection system S.

[0021] About Light Source 1 First, the light source 1 of the visual inspection system S will be described with reference to FIG. 1(1) and FIG. 2(1). The light source 1 is a linear LED (light emitting diode) that is located below the upper part of the box 4 and above and outside the visible end of the nori B. The light source 1 illuminates the nori B placed on the stand 5 at the bottom of the box 4. The light source 1 is set as follows: it is set to irradiate the seaweed B from one direction at an acute angle with a linear, angled oblique irradiation light L. The irradiation angle α is set to, for example, about 20 to 30 degrees, facing inward from the perpendicular line. That's all for light source 1.

[0022] <Light source side polarizing plate 2> Next, the light source side polarizing plate 2 of the visual inspection system S will be described with reference to FIG. 1(1). The light source-side polarizing plate 2 is attached to the front surface of the light source 1, and transmits only light of a certain polarization plane out of the light L emitted from the light source 1. That is, the irradiated light L emitted from the light source 1 is filtered by the light source-side polarizing plate 2, and only light with a certain polarization plane is transmitted. Of the irradiated light L, which is natural light from the light source 1, only the polarized component that enters linearly is transmitted as is. The light source side polarizing plate 2 is as described above.

[0023] <<About the viewing side polarizing plate 3>> Next, the viewer-side polarizing plate 3 of the visual inspection system S will be described with reference to FIG. 1(1) and FIG. 2(1). The viewer-side polarizing plate 3 is located on the viewer P side outside the box 4, with its polarization plane shifted by 90 degrees. Light L emitted from the light source 1 passes through the light source-side polarizing plate 2 and is received as reflected light R via the seaweed B. A foreign substance A inspection is then performed visually based on the light transmission and light blocking by the viewer-side polarizing plate 3. The viewer-side polarizing plate 3 is set at a plate angle β, for example, of about 20 to 45 degrees, facing outward from the perpendicular line, so that the viewer P can easily see the seaweed B in the box 4 from the outside. The viewer-side polarizing plate 3 has a polarization plane shifted by 90 degrees relative to the light source 1, i.e., the light having a constant polarization plane. The irradiated light L from the light source 1, passing through the light source-side polarizing plate 2, is reflected by the seaweed B and then received as reflected light R. Thus, based on the filter state of the viewer-side polarizing plate 3, that is, based on whether the received reflected light R is transmitted or blocked, the viewer P determines and inspects whether or not a foreign substance A is present. The viewing-side polarizing plate 3 is as described above.

[0024] <About polarized glasses for the viewing side 6> Next, the viewing-side polarized glasses 6 of the visual inspection system S will be described with reference to FIG. 1(2). In this visual inspection system S, the viewer-side polarizing plate 3 can be replaced with viewer-side polarizing glasses 6. The configuration, function, etc. of the viewer-side polarized glasses 6 are the same as those described for the viewer-side polarizing plate 3, except for whether they are attached to the box 4 or worn by the viewer P. That is, the viewing-side polarized glasses 6 are placed on the viewing side with the polarization plane shifted by 90 degrees, and the light L emitted from the light source 1 that passes through the light source-side polarizing plate 2 is received as reflected light R through the seaweed B, and foreign matter A is visually inspected based on the light transmission and light blocking of the viewing-side polarized glasses 6.

[0025] If there is no foreign substance A, the reflected light R is blocked by the viewing-side polarized glasses 6 and does not pass through, so no light enters when viewed. On the other hand, if foreign matter A is present, the diffuse reflection causes a shift in the polarization plane of the reflected light R, and the reflected light R is not blocked by the viewing-side polarized glasses 6 but passes through, becoming a light-entering state when viewed, which leads to the determination that foreign matter A is present. The following is a comparison between the view-side polarized glasses 6 and the view-side polarizer 3. Unlike the view-side polarizer 3, the view-side polarized glasses 6 do not get in the way or become an obstacle when manually removing foreign matter A, allowing manual work to be done without worry. Also, with the view-side polarizer 3, your face may be reflected, making it difficult to see foreign matter A, but this does not occur with the view-side polarizer 6. The above is the case with regard to the viewing side polarized glasses 6.

[0026] 《Effect, etc.》 The visual inspection system S for foreign substances on the surface of laver B of the present invention is configured as described above. (1) The work of removing foreign matter A attached to seaweed B is carried out while visually inspecting seaweed B. The visual inspection is performed with the assistance of visual inspection system S.

[0027] (2) The visual inspection system S is used under the assumption that the reflection characteristics of seaweed B are almost total reflection. As shown in Figure 1(1), light L emitted from light source 1 passes through light source-side polarizing plate 2, and light with a certain polarization plane is reflected by seaweed B and received as reflected light R by viewing-side polarizing plate 3. The viewing-side polarizing plate 3 has a polarization plane shifted by 90 degrees, and the presence or absence of foreign matter A is determined and inspected based on whether the light is transmitted or blocked (see also Non-Patent Document 1). The operation of the visual inspection system S will be described in detail below.

[0028] (3) First, if there is no foreign substance A attached to the seaweed B, the reflected light R is blocked by the viewing-side polarizing plate 3 and does not pass through, so no light enters when visually inspected. As a result, the viewer P, i.e., the worker, determines, inspects, and recognizes that there is no foreign substance A. That is, as shown in Table 1, in this case, the outer surface of the seaweed B is entirely black, and the reflected light R is in the desired fixed direction with no deviation in the polarization plane. Therefore, as expected, the light is blocked by the viewing-side polarizing plate 3, and no light enters when viewed visually.

[0029] (4) In contrast, as shown in Figures 4(1) and 4(2), if foreign substance A is present, its diffuse reflection causes a shift in the polarization plane of reflected light R, and reflected light R is not blocked by the viewing-side polarizing plate 3 but passes through, resulting in a light-entering state when viewed visually. The viewer P, i.e., the worker, determines, inspects, and recognizes that foreign substance A is present, and then performs the work of removing foreign substance A. That is, as shown in Table 1, foreign matter A is scattered on the outer surface of seaweed B, and each of them causes diffuse reflection in multiple directions, causing a deviation in the polarization plane of reflected light R. As a result, the light is not blocked by the viewer-side polarizing plate 3 and is transmitted, becoming visible to the naked eye. In the case of foreign matter A, which causes diffuse reflection, its brightness is extremely high. This visual inspection system S is first used in this manner.

[0030] (5) Now, as shown in Figures 4(3) and 4(4), if the seaweed B has discoloration C or unevenness D, a deviation occurs in the polarization plane of the reflected light R. As a result, some of the reflected light R is not blocked by the viewing-side polarizing plate 3 and is transmitted, resulting in an incident light state when viewed by the eye. However, the reflection of discoloration C and irregularities D is suppressed by the setting of light source 1, and the light incident on the surface is uniform and the brightness of the incident light is low when visually inspected. Therefore, foreign matter A can be easily distinguished and found regardless of discoloration C and irregularities D. As shown in Table 1, this is as follows (6), (7), and (8).

[0031] (6) First, discoloration C (e.g., light brown) and irregularity D (fuzziness) occur on the entire outer surface of Nori B (note that irregularity D occurs only on the entire reverse side of the outer surface). Discoloration C reflects light R not only in the intended direction but also in other directions, causing a slight deviation in the plane of polarization of reflected light R. Asperity D causes some diffuse reflection in other directions at the convex parts, causing a slight deviation in the plane of polarization of reflected light R. Therefore, both discoloration C and irregularities D are in a light-entering state when visually inspected. The light-entering brightness is not as high as that of foreign matter A, and is medium or low in brightness according to the level of reflected light R.

[0032] (7) Now, in the visual inspection system S of the present invention, the light source 1 is linear and is set to illuminate the seaweed B at an acute angle from a diagonal direction above and outside the visual end of the seaweed B. As a result, the surface reflection of the color faded areas C and unevenness D of the seaweed B is kept low. As a result, as shown in Figure 3(1), when visually inspected, the number of bright and dark areas caused by the color faded areas C and unevenness D is reduced. The brightness difference between the bright and dark areas is also reduced. Therefore, the bright and dark areas caused by the color faded areas C and unevenness D are not noticeable (compare with the conventional example in Figure 3(2)).

[0033] (8) In this way, the discoloration C and unevenness D that form the overall background / backbone of seaweed B have low light intensity to begin with, and the contrast between light and dark is not noticeable. In contrast, foreign substance A, although small in size, is the brightest and scattered, making it highly visible. This makes foreign substance A easy to distinguish and discover, regardless of discoloration C or unevenness D. The effects etc. are as described above. [Explanation of symbols]

[0034] A. Foreign body B Seaweed C. Color fading D Unevenness L irradiation light R Reflected light P Visual observer S Visual Inspection System α Irradiation angle β plate angle 1 light source 2 Light source side polarizing plate 3. Viewing side polarizer 4 box body 5 Stand 6 Polarized glasses for the viewing side

Claims

1. This auxiliary system is used for visual inspection of foreign matter when removing foreign matter attached to the outer surface of laver, and includes a box whose side of the laver facing the viewer is open, a light source, a light source side polarizing plate, and a viewer side polarizing plate provided in the box, The light source is a linear rod-shaped or line-shaped LED arranged above and outside the visible end of the nori seaweed, and illuminates the nori seaweed at an irradiation angle of 20 to 30 degrees toward the inside of the box, which is the back of the box, with respect to a perpendicular line extending from the top surface to the bottom surface of the box. the light source-side polarizing plate is attached to the light source and transmits only light of a certain polarization plane from the light source; The view-side polarizing plate is provided on the view side of the box body, is inclined downward toward the outside of the box body at a set angle of 20 degrees to 45 degrees with respect to a perpendicular line extending from the top surface to the bottom surface of the box body, and has a polarization plane shifted by 90 degrees, and receives light emitted from the light source that has passed through the light-source-side polarizing plate as reflected light through the seaweed, and visually inspects for foreign objects based on the light transmission and light blocking of the view-side polarizing plate, When there is no foreign matter, the reflected light is blocked by the polarizing plate on the viewing side and does not pass through, so no light is incident upon viewing. If a foreign object is present, the plane of polarization of the reflected light is shifted due to diffuse reflection, and the reflected light is not blocked by the viewing-side polarizing plate but passes through, resulting in a light-entering state when viewed visually, which is determined to indicate the presence of a foreign object. A visual inspection system for foreign matter on the surface of seaweed.

2. This auxiliary system is used for visual inspection of foreign matter adhering to the outer surface of laver during removal work, and includes a box whose side of the laver faces the viewer and is open, a light source provided in the box, a light source-side polarizing plate, and viewer-side polarized glasses. The light source is a linear rod-shaped or line-shaped LED arranged above and outside the visible end of the nori seaweed, and illuminates the nori seaweed at an irradiation angle of 20 to 30 degrees toward the inside of the box, which is the back of the box, with respect to a perpendicular line extending from the top surface to the bottom surface of the box. the light source-side polarizing plate is attached to the light source and transmits only light of a certain polarization plane from the light source; The viewer of the seaweed wears the viewer-side polarized glasses, and when worn, the polarization plane is shifted by 90 degrees. Light emitted from the light source that has passed through the light source-side polarizing plate is received as reflected light through the seaweed, and a foreign substance inspection is performed visually based on the light transmission and light blocking of the viewer-side polarized glasses. When there is no foreign matter, the reflected light is blocked by the polarized glasses on the viewing side and does not pass through, so no light enters when viewed visually. If a foreign object is present, the plane of polarization of the reflected light is shifted due to diffuse reflection, and the reflected light is not blocked by the polarized glasses on the viewing side but passes through, resulting in a light-entering state when viewed visually, which is determined to indicate the presence of a foreign object. A visual inspection system for foreign matter on the surface of seaweed.

3. If the seaweed has discoloration or unevenness, the polarization plane of the reflected light will shift, and some of the reflected light will be transmitted without being blocked, resulting in light being incident when viewed visually. The reflection of discoloration and unevenness is suppressed by the light source being set at the angle, and the light is incident on the entire surface and the brightness of the incident light is low when visually inspected, so foreign matter can be distinguished and found regardless of discoloration and unevenness. The visual inspection system for foreign matter on the surface of seaweed according to claim 1 or 2, characterized in that:

4. The box has a seaweed stand on the bottom, and the stand is inclined downward from the back side of the box to the viewing side. The visual inspection system for foreign matter on the surface of seaweed according to claim 1 or 2, characterized in that:

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