JP4350553B2 - Tablet inspection system - Google Patents

Description

The present invention relates to a technique for inspecting defects such as black spots and chips that may occur on the surface of a tablet by imaging, for example, a tablet having a substantially disc shape, and particularly, a front surface or a back surface of a tablet or the like. The present invention relates to a novel tablet inspection system in which the side surface is imaged at the same time as the surface image so that the quality of the tablet can be judged at low cost and high efficiency.

In pharmaceuticals, dietary supplements, and the like, tablets are known in which raw materials and ingredients are mechanically compressed by a mold or the like and formed into an easy-to-drink shape. This is also called a tablet, and generally flat discs are widely distributed.
By the way, due to the manufacturing method described above, such a tablet may cause chipping or cracking in a corner portion or the like, or dirt or black spot foreign matters may adhere to the surface during compression molding. For this reason, in order to receive such a defect inspection, the appearance of a tablet that has finished the actual manufacturing process is generally imaged by a camera.

In this imaging, it is necessary to copy the entire surface of the tablet, and a conventional imaging method will be described below. First, the imaging method shown in FIG. 21A is a method of imaging from a total of six directions, for example, front and rear, left and right, and top and bottom of the tablet W. At this time, six cameras C may be installed in each direction in advance, and images may be taken simultaneously from the six directions, or one camera C may be moved as appropriate to move the front surface F and the back surface B of the tablet W. It is also possible to sequentially image the side surfaces S. Of course, in such a case, it is preferable to image the side S from at least three directions or four directions.
21B, for example, when the tablet W has a shape that is easy to roll, such as a disk shape, the tablet W is transferred while rolling using the shape, and the front surface F, The back surface B and the side surface S are imaged.
Furthermore, the imaging method shown in FIG. 21 (c) is a method in which, for example, the tablet W is continuously imaged from above while the tablet W placed on the transparent turntable T is rotated. In this method, when the tablet W is rotated once, the photographing of the front surface F and the side surface S is completed. In this case, naturally, the back surface B is imaged by another camera C, or after the front surface F and the side surface S are imaged, the position of the camera C is changed.

The methods described above are conventional imaging methods. However, all of these conventional methods have a problem in that there is a large amount of information (data amount) for determination. That is, for example, in FIGS. 21 (a) and 21 (b), five or six image processes have to be performed for one tablet W even if the photographing is performed once in each direction, and FIG. 21 (c). In this case, the amount of information handled is enormous because it is a video process. For this reason, not only the imaging apparatus but also the apparatus that performs subsequent image processing and determination, naturally, an ability to meet the enormous amount of information is required, and it is inevitable that the imaging apparatus and the entire system are increased in cost and size. The processing time was accordingly increased.
In the imaging method shown in FIG. 21 (b), the tablet W is assumed to roll, but for example, some tablets W are not suitable for rolling, such as a triangle or a quadrangle. Therefore, the imaging technique is not necessarily suitable for all tablets W.

Also, since tablets W are taken directly by humans and taken into the body, not only the related devices and the surrounding environment are clean (hygienic), but also all inspections (imaging) are essential. In the determination, high accuracy (accuracy) is required, and this tends to further increase the cost of the entire inspection system including the imaging device.
In addition to this situation, in recent years, health orientation has become a social boom, and tablet-type nutritional supplements and health foods are actively developed and supplied to the market. For this reason, there has been a strong demand for a new technique capable of constructing an apparatus and a system at the lowest possible cost while performing 100% inspection of tablets with high accuracy and high efficiency.

The present invention was made by recognizing such a background, and the tablet is an inspection object, and by simultaneously imaging the side surface that becomes the non-direct viewing surface simultaneously with the front and back surfaces that become the direct viewing surface, This is an attempt to develop a new tablet inspection system that minimizes the amount of input data, makes it possible to make good / bad judgments quickly and extremely accurately, and that allows an imaging device and system to be constructed at low cost.

That is, the tablet inspection system according to claim 1 comprises:
An imaging unit (6) for imaging the surface of the tablet (W) to be taken, a transport unit (7) for sending tablets (W) to the imaging unit (6) one by one, and taking the captured images on the tablet surface An image processing unit (8) for determining whether there is a defect such as a chip or a foreign object, and a system for inspecting and determining whether the tablet (W) is good or bad,
The imaging unit (6) includes a special optical unit (3) mainly including a convex lens (13) and an illumination unit (4) for illuminating a tablet (W) to be inspected (W) . The camera unit (2) is a main component, and the camera unit (2) images the surface of the tablet (W) .
Also, the camera unit (2) is a convex lens (13), tablets front surface of the (W) (F) or rear surface (B) provided so as to face the tablets front surface of the (W) (F) Or the back surface (B) is the main imaging surface (M) ,
When imaging the tablet (W), the illumination unit (4) causes both the main imaging surface (M) as the direct viewing surface (V ) and the side surface (S) as the non-direct viewing surface (NV) of the tablet (W). While illuminating the light, the main imaging surface (M) and the side surface (S) of the tablet (W) are imaged almost entirely,
In addition, for the side image of the tablet (W) , taking into account that the entire outer periphery of the main imaging surface (M) is imaged with a substantially constant width and includes more aberration toward the outer side, during front side imaging and back side imaging The side (S) of the tablet (W) is imaged twice in
In determining whether the side of the tablet is good or not, the image data on the front side (F) and the side (S) taken at the same time, and the back side (B) and the side (S) taken simultaneously on the back side are taken. It is characterized in that the tablet (W) having no defect in both of the imaging data with the image data is judged as a non-defective product .

The tablet inspection system according to claim 2 is characterized in that, in addition to the requirement according to claim 1, the camera unit (2) images a defect having a minimum size of about 60 μm. is there.

Furthermore, the tablet inspection system according to claim 3 is one-shot imaging in which the camera unit (2) images the tablet (W) once in an extremely short time in addition to the requirements of claim 1 or 2. It is characterized by this.

Further, in the tablet inspection system according to claim 4 , in addition to the requirement according to claim 1, 2, or 3 , the transport unit (7) holds the tablet (W) in an upright position in an upright position. It is characterized by being transported to the imaging unit (6) .

Further, in the tablet inspection system according to claim 5 , in addition to the requirement according to claim 4 , the transport section (7) includes a transport conveyor (28) having a transport surface formed substantially vertically, and the tablet (W) The front surface (F) or the back surface (B) is adsorbed to the transport surface, so that the tablet (W) is sent to the imaging unit (6) in a standing state.

Further, in the tablet inspection system according to claim 6 , in addition to the requirement according to claim 1, 2, 3, 4, or 5 , the transport unit (7) is configured to arrange the aligned tablets (W) at substantially the same pitch. those made be characterized by and is intended to transfer timing.

The above-described problems can be solved by using the configuration of the invention described in each of the claims. That is, according to the first or second aspect of the invention, in general, only images taken from two directions, the front side and the back side, of tablets that are often imaged and determined from the six directions of front and rear, left and right, and top and bottom. Since the inspection can be carried out at a very low cost, the inspection can be carried out very efficiently, and the entire system can be constructed very simply and inexpensively. Further, since the side image is taken twice on the front side and the back side, the inspection accuracy of the side surface including distortion (aberration) can be remarkably improved.
In addition, a non-direct viewing surface that does not normally enter the field of view and cannot be clearly seen can be imaged at the same time as the direct viewing surface, so that a camera is required when imaging the entire surface of a three-dimensional object (tablet). The number of images and the number of times of imaging can be reduced, and imaging can be performed easily. In addition, since the imaging data (input information) for inspecting the surface of the object to be inspected is small, the time required for the processing can be shortened and the inspection can be performed quickly.
In addition, since the special optical unit can be formed by using a commercially available general convex lens as a main member, the special optical unit, and thus the imaging device can be manufactured at a relatively low cost.

  Furthermore, according to the third aspect of the invention, since the imaging of the object to be inspected (tablet) is one-shot imaging in an extremely short time, for example, much less data compared to moving image processing using a video camera. The surface of the object to be inspected can be inspected by the amount, and a simpler form can be adopted in terms of both cost and structure.

According to the fourth aspect of the invention, since the tablet is fed into the imaging unit (camera field of view) without rolling the tablet, imaging and inspection can be performed efficiently regardless of the shape of the tablet. In other words, even a tablet with a shape unsuitable for rolling can be inspected very smoothly.

According to the fifth aspect of the present invention, since the tablets are sucked and transported to the transport surface formed substantially vertically, the tablets can be stably fed in a state of standing substantially vertically.

According to the sixth aspect of the invention, since the aligned tablets are fed to the imaging unit (camera field of view) at a constant pitch and timing, the tablets can always be fed to the center position of the camera field of view, and imaging can be reliably performed. Yes. Therefore, it is easy to synchronize, and management (tracking synthesis) in which the front side image and the back side image are combined with each other from the same tablet is extremely easy.

  The best mode of the present invention is as described in the following examples. In this embodiment, a disk-shaped tablet W is mainly described as an example of an inspection target (imaging target). However, as an object to be inspected (same reference numeral W as a tablet), a disk-shaped tablet W is used. The tablet W is not limited to the tablet W, and may be a tablet W that is relatively unsuitable for rolling, such as a substantially triangular shape or a rectangular shape (see FIG. 19).

  Further, in the present invention, in the tablet W, the circumferential side surface S that is difficult to see as it is while being viewed straight from the front while the front surface F and the back surface B that are substantially circular is viewed straight from the front is simultaneously imaged. The direct view surface of the inspection object W is V, and the non-direct view surface is NV. That is, in the tablet W, the front surface F and the back surface B become the direct viewing surface V, and the side surface S becomes the non-direct viewing surface NV. In the present embodiment, the front surface F and the back surface B of the tablet W are generally collectively referred to as the main surface F and the back surface B of the tablet W. The imaging surface M is assumed. Incidentally, the distinction between the “front side” and the “back side” in the tablet W is not necessarily clear. In this embodiment, for convenience, the first image is taken as “front” and the opposite side is taken as “back”.

Moreover, since the tablet W is formed by mechanically compression-molding raw materials and compositions, defects may occur on the surface thereof. Specifically, dirt or sunspot foreign matter may adhere to the tablet surface, or chipping or the like may occur at the corner or the like. In this embodiment, in order to remove such defects from the production line, the entire surface of the tablet W is imaged and inspected. Hereinafter, after describing the imaging device 1 that simultaneously captures the direct-viewing surface and the non-direct-viewing surface, the tablet inspection system A of the present invention to which this device is applied will be described.

  As shown in FIGS. 1 and 2, the imaging device 1 has a side surface S formed in the depth direction from the main imaging surface M at the same time as the main imaging surface M (front surface F or back surface B) of the tablet W. The camera unit 2 is a main component for imaging. The camera unit 2 integrally includes a special optical unit 3 that simultaneously images the main imaging surface M (direct viewing surface V) and the side surface S (non-direct viewing surface NV) and an illumination unit 4 that illuminates the tablets W almost uniformly. However, since it has the same basic structure as a normal camera, it has a monochrome type CCD area sensor camera 11 and a lens 12 as shown in FIG. 2A, for example. Here, reference numeral 12 a in the drawing denotes a close-up ring attached to the lens 12.

In order to simultaneously image the front side F and the side S of the tablet W, for example, if the camera unit 2 is installed obliquely upward with respect to the front side F of the tablet W (see FIG. 21C), the front side F In the present invention, the camera unit 2 is provided so as to be substantially opposed to the main imaging surface M of the tablet W, and normally only the main imaging surface M can be imaged. However, it is a great feature that the side surface S is imaged at the same time. Moreover, the imaging of the side surface S is to take an image of the entire circumference. Such imaging is one-shot photography for a very short time, for example, at a shutter speed of about 1/8000 second (125 μs).
Moreover, in FIG. 1, although the form which imaged the tablet W of the state stood substantially perpendicular | vertical was shown from substantially horizontal, the imaging form can take the various form corresponding to the conveyance form etc. of the tablet W, For example, in Fig.2 (a), the tablet W in the laid state is imaged from a substantially vertical direction. Hereinafter, the special optical unit 3 and the illumination unit 4 incorporated in the camera unit 2 will be described.

  First, the special optical unit 3 will be described. As shown in FIG. 2A as an example, the special optical unit 3 includes a convex lens 13 as a main constituent member, and the convex lens 13 is installed facing the tablet W. That is, the convex lens 13 and the tablet W are installed so as to be substantially parallel to each other, and the tablet W is placed within the focal distance of the convex lens 13. In an actual inspection, there is almost no form in which the tablets W are imaged one by one with the tablets W kept stationary, and the images are generally taken while the tablets W are being transported constantly. Means to convey in such a state to the convex lens 13 (camera unit 2). Here, symbol AR in the figure is a camera field of view showing an imaging area on the transport line, and the tablet W is transported at a substantially constant timing so as to pass through a substantially center position of the camera field of view AR. Then, when the tablet W comes to substantially the center position of the camera visual field AR, the imaging is performed in synchronization, and reference numeral 14 in the figure is a synchronization sensor for achieving this synchronization.

Hereinafter, the principle by which the main imaging surface M and the side surface S of the tablet W can be simultaneously imaged by the convex lens 13 will be described.
A thin line (light beam) shown in the camera unit 2 in FIG. 2A shows what image the main imaging surface M and side surface S of the tablet W form with the convex lens 13, thereby It can be understood that a substantially circular image is formed while the main imaging surface M is enlarged, and that the side surface S forms an image with a substantially constant width on the outer periphery thereof. That is, when the tablet W is viewed through the convex lens 13, the main imaging surface M and the side surface S of the tablet W appear three-dimensionally as a substantially truncated cone shape, and this is captured as a two-dimensional planar image. This is an image in which the side surface S is formed as a double concentric circle on the entire outer periphery of the imaging surface M (circular image).

Therefore, in practice, the side surface S of the tablet W having substantially the same diameter (the upper and lower sides of the side surface in FIG. 2A are denoted by U and D) has a lower side surface D that appears on the outermost side in the image. The image is formed as a concentric circle larger than the upper side U. Therefore, the image of the side surface S tends to include more distortion (so-called aberration) than the side surface upper portion U, as it goes to the side surface lower portion D. In the present invention , in consideration of such aberration, the side surface S is imaged twice in both the front surface imaging and the back surface imaging.

  Further, as a reference example for simultaneously imaging the main imaging surface M and the side surface S, FIG. 2B shows a front side image and a back side image when a cube is an inspection target. In this drawing, in order to easily understand how the planar image of the cube that has passed through the special optical unit 3 looks, the cube is expressed as a dice with eyes on each surface. Incidentally, if the dice has a total of seven eyes on the two opposing faces, and thus a solid (tablet W) that has some relationship between the two opposing faces that cannot be normally viewed is a subject of inspection. The method of the present invention that simultaneously images and inspects such two surfaces is considered to be particularly effective.

Next, the illumination unit 4 that illuminates the tablet W during imaging will be described. As shown in FIG. 2A as an example, the illumination unit 4 includes a side ring illumination 15 that illuminates the side S of the tablet W almost uniformly, and a coaxial that illuminates the main imaging surface M of the tablet W from the front. The epi-illumination 16 is provided.
The side ring illumination 15 includes, for example, a plurality of white LEDs 17 and is equally arranged so as to surround a tablet W to be imaged (approximately the center position of the camera visual field AR).

On the other hand, the coaxial epi-illumination 16 includes a half mirror 18 and a white LED 19 as an example, and reflects the light emitted from the white LED 19 to the half mirror 18 to illuminate the tablet W from the front. . By these, the surface of the tablet W, that is, the main imaging surface M and the side surface S is illuminated as a whole, and the tablet W is imaged by the camera unit 2 through the half mirror 18.
In addition, when imaging of the tablet W requires a larger amount of light, the side-ring illumination 15 and the coaxial epi-illumination 16 may be applied with pulsed illumination that matches the shutter speed of the camera. Is possible.

  In addition, when examining tablet color in addition to burrs, cracks, etc., that is, when examining tablet color differences (color differences) or mixing of different varieties based on tablet color differences, etc. It is possible to attach a color filter 20 of an appropriate color to match the tablet color and determine the tablet color by pseudo color processing using two colors.

  Further, as a method for simultaneously imaging the main imaging surface M and the side surface S of the tablet W, a method using a mirror is possible in addition to the method using the convex lens 13, but the method using a mirror is included in the present invention. It is a related reference form. In the method using a mirror, for example, as shown in FIG. 3, a cylindrical mirror having a substantially truncated cone shape is arranged inside and outside instead of the convex lens 13. In other words, two cone-side mirrors 23 each having a substantially truncated cone shape are doubled with an appropriate interval. Here, when the two mirrors are distinguished between the inner side and the outer side, the inner one is the cone side mirror 23A and the outer one is the cone side mirror 23B. In addition, when installing the cone side mirror 23, it installs so that the substantially frustoconical expansion part (expansion part) may face the tablet W, and the tablet W is on the central axis of the two cone side mirrors 23. On the other hand, the main imaging surface M is placed in a substantially orthogonal state. The special optical unit 3 using a mirror is, for example, composed of two cone side mirrors 23 as main members as described above. Hereinafter, the principle that the main imaging surface M and the side surface S of the tablet W can be simultaneously imaged by this. Will be described.

  The light rays (lines with arrows) shown in FIG. 3 above show how the main imaging surface M and the side surface S of the tablet W form an image by the cone side mirror 23. Thus, it can be seen that the main imaging surface M of the tablet W can be directly viewed from the front (viewpoint), while the side S can be viewed indirectly by the reflection of the cone side mirror 23. That is, when the tablet W is viewed straight from the direction of the main imaging surface M through the cone side mirror 23, the main imaging surface M can be directly viewed from the inner opening of the cone side mirror 23A. On the other hand, the side surface S is sequentially reflected on the inner surface of the cone side mirror 23B and the outer surface of the cone side mirror 23A, and an image is formed on the front side (viewpoint position).

As can be understood from such a principle, by appropriately adjusting the inclination angle (taper angle) of the cone side mirror 23, it is possible to suppress distortion (aberration) of the image obtained by imaging the side surface S as much as possible. Of course, in order to suppress such aberration as much as possible, it is also conceivable that the mirror shape is appropriately a truncated pyramid shape instead of a cone shape (substantially truncated cone shape) according to the shape of the tablet W, for example.
Note that the above description merely describes the principle of the special optical unit 3 using a mirror. Even in such a method, naturally, the surface of the tablet W, that is, the main imaging surface M and the side surface is used for imaging. The lighting which illuminates S uniformly is required.

The imaging device 1 that takes the main imaging surface M and the side surface S of the tablet W at the same time, that is, the imaging device 1 that can simultaneously image the non-direct viewing surface NV that does not enter the visual field as it is, as described above. The tablet inspection system A according to the present invention, which adopts the configuration and which comprehensively performs a series of operations from the surface imaging of the tablet W to the determination by applying the imaging apparatus 1 as described above, will be described below.
As an example, as shown in FIG. 1, the tablet inspection system A is an inspection target in the imaging unit 6 that simultaneously images the main imaging surface M and the side surface S of the tablet W, and mainly in the imaging unit 6 (camera visual field AR). It comprises a transport unit 7 that feeds tablets W one by one, and an image processing unit 8 that takes in mainly captured information (image) and determines whether the target tablet W is good or bad. Hereinafter, each component will be described.

  The imaging unit 6 is substantially configured by the imaging device 1 described above, and the camera unit 2 is a main component. Here, for one tablet W, one camera unit 2F that simultaneously images the front side F and the side S and one camera unit 2B that simultaneously images the back side B and the side S are used. The tablet W is imaged. That is, the side surface S of the tablet W is imaged twice by the front side imaging camera unit 2F and the back side imaging camera unit 2B. This is because the image of the side surface S includes aberrations. As a result, it is possible to determine whether the product is good or not with high accuracy and to more reliably select the good product and the defective product. When the tablets W are flowed in a plurality of rows, two cameras are provided for each line. For example, in this embodiment, the tablets W are sent in five rows, so a total of ten camera units 2 are installed. ing.

Next, the transport unit 7 will be described. The transport unit 7 transports the tablets W one by one so as to pass through the camera visual field AR. As shown in FIG. 1, as an example, the transport unit 7 stores the tablets W to be inspected and removes them almost quantitatively. The apparatus includes a fixed amount supply device 26, an alignment device 27 for aligning the taken-out tablets W in an appropriate posture (here, standing), and a transport conveyor 28 for feeding the tablets W to the camera visual field AR in this posture. .
The fixed amount supply device 26 includes a hopper 29 that temporarily stores the tablets W, and a supply conveyor 30 that takes out the tablets W from the hopper 29 in a substantially constant amount and sends them to the aligning device 27 in a separated state.
Further, the alignment device 27 supplies the tablets W sent by the quantitative supply device 26 to the transport conveyor 28 by arranging them in a row in an appropriate regulation posture, such as standing upright. In the present embodiment, the aligning device 27 is constituted by the cylindrical member 31 having substantially the same cross-sectional shape as the tablet W, and the tablets W are arranged in a regulated posture while passing through the inside thereof, and are also transport conveyors. Sent to the position facing 28.

The transport conveyor 28 mainly feeds the tablets W to the center position of the camera visual field AR while maintaining the regulated posture, and the tablets W are preferably sent at equal intervals and at the same timing. This is because imaging is performed in a timely manner when the tablet W is sent to substantially the center of the camera field of view AR, so that it is easy to synchronize.
In this embodiment, the management of regularly sending the tablets W, such as the pitch and timing at which the tablets W are sent, is managed by a line computer (not shown) that controls the transport conveyor 28. In this sense, the transport unit 7 or It can be said that the transport conveyor 28 is a part that feeds the tablets W while synchronizing with the camera visual field AR.

In the present embodiment, when the tablets W are sent to the camera visual field AR, the tablets W are transported in an upright state. For this reason, the transport conveyor 28 transports the tablets W while the transport surface is formed substantially vertically. A suction mechanism (not shown) for sucking on the surface is incorporated. Furthermore, on such a structure, the conveyance conveyor 28 adsorbs the back surface B of the tablet W, the front side imaging conveyor 28F which images the front surface F and the side surface S in the meantime, and the front surface F of the tablet W are arranged. A back side imaging conveyor 28B for picking up and imaging the back surface B and the side surface S in the meantime is provided. In this embodiment, the front side imaging conveyor 28F as shown in FIG. 4A is formed in the first half of the transport line, and the back side imaging as shown in FIG. 4C is formed in the second half of the transport line. Conveyors 28B are formed, and these conveyors are formed so as to overlap somewhat as shown in FIG. 4B. This is because the suction surface of the tablet W is switched from the back surface B to the front surface F, and the tablet W is smoothly transferred from the front side imaging conveyor 28F to the back side imaging conveyor 28B.
At the end of the conveyor 28, there are provided discharge gates 32 for separating the tablets W that have been judged as good or defective.

  According to such a transport mode, the tablets W are fed on the transport conveyor 28 in a non-rotating state, and during that time, imaging is performed from both the front side and the back side. For this reason, it is easy to align (superimpose) the captured front side image and back side image, and even if the tablet W itself is a triangle or the like that is not suitable for rolling, the entire surface can be easily inspected. .

  Next, the image processing unit 8 will be described. The image processing unit 8 is a part that processes the captured image of the tablet W to inspect for the presence or absence of a defect and determines whether the tablet W that has been inspected is good or bad. As an example, as shown in FIG. An image computer 35 for inspecting the front side image and the back side image in the same tablet W, a host computer 36 for comprehensively managing the type and detection parameters of the tablets W to be inspected, the results of inspection by the image computer 35, and the like The monitor 37 that displays the image and the determination result is used as a main component.

  The image computer 35 processes the image data captured by the camera unit 2 to extract defects. The image computer 35 includes a camera unit 2F that images the same tablet W from the front side and the back side. 2B is connected as a pair, and defects are efficiently extracted by comparing the front side image and the back side image captured in the same tablet W or by superimposing them. Here, five image computers 35 are also provided to convey the tablets W at a time in five rows.

The host computer 36 performs product type information management of tablets W, setting information management such as inspection condition values and device setting parameters, tabulation management of inspection results, device status information management, and the like.
The monitor 37 displays the inspection state, inspection results, and the like in real time.
Furthermore, reference numerals 38 and 39 in the figure denote a keyboard and a mouse attached to the host computer 36, which are mainly used for inputting information such as numerical input and selection of inspection items.
Reference numeral 40 in the figure denotes a video switcher that selects, for example, which image computer 35 video is to be displayed on the monitor 37, and also serves as a network connecting the image computer 35 and the host computer 36. .

  In this embodiment, the tablets W are transported by the transport conveyor 28 so as to pass through the camera visual field AR at substantially the same pitch, the same timing, and the same posture. For this reason, the management of combining the front side image and the back side image with those of the same tablet W, so-called tracking synthesis, is substantially managed by the line computer of the transport conveyor 28 described above. Of course, the tracking control by the line computer is not limited to combining images of the same tablet W, but is continued until the tablet W reaches the discharge gate 32. That is, the tracking control by the line computer is continuously performed until the tablets W that have been judged as good or bad are accurately distributed to the correct discharge gates 32 respectively.

As described above, in the tablet inspection system A of the present invention, the surface of the tablet W can be inspected with very little image data imaged from the front side and the back side, whereby the tablet W can be inspected with high efficiency, and the imaging apparatus 1 The entire system including can be constructed at a very low cost. The imaging of distortion (aberration) including the side surfaces S, since performed twice during the imaging of the front side F and the back side B, it causes comparison or superimposing e.g. front side image and the back side image, with higher precision Defects can be extracted, and the reliability of the pass / fail judgment can be made more reliable.

The tablet inspection system A of the present invention has the basic structure as described above. Hereinafter, a test image obtained by taking an image of the tablet W by this system will be described (see FIGS. 5 to 15).
In addition, since these test images imaged the tablet W without using the coaxial epi-illumination 16, the main imaging surface M (particularly the central portion) is an image that is somewhat dark. Moreover, the defect of the tablet W used for this test is a pseudo defect which processed the actual tablet W and made it adhere intentionally.
Incidentally, the defects (inspection items) of tablets W that can be detected by this system include surface contamination, foreign matter adhesion (black spot foreign matter), chipping (cracking), cracks (cracking), different colors, different sizes, different shapes, and missing prints. (When there is printing on the tablet surface), the score line is missing, and mixing of different varieties can be inspected by the size, shape and color of the tablet W. For example, a foreign matter or chip that can be detected can be detected with a minimum size of about 30 μm, but is about 60 μm or more in view of the safety factor.

  First, as an example, the test image shown in FIG. 5 has a black spot defect on the side S of a white tablet having a diameter of about 8 mm and a thickness of about 3.5 mm. Here, “1” of the signs “1F”, “1B”, and “1S” attached to the test image indicates a sample number, and “F”, “B”, and “S” are sequentially viewed from the front side. Means an image (front side image), an image viewed from the back side (back side image), and an image viewed from the side (side view image) (sample numbers and display of each image are the same in the test image described later) ). Of course, this side view image “1S” is not taken in actual inspection, and here, how the defect on the side surface S appears in the front side image “1F” and the back side image “1B”. This is for easy understanding. Incidentally, the side view image is two-cut imaged, and is distinguished by attaching branch numbers such as “1S-1” and “1S-2”.

  Here, the defects (A) and (B) of the front side image “1F”, the back side image “1B”, and the side view image “1S” are the same. As described above, the tablet W appears three-dimensionally in the shape of a truncated cone by the special optical unit 3 as described above. However, since the images taken on a plane are the front side image and the back side image, the image is mainly used as the image. The side surface S is formed as a double concentric circle around the imaging surface M. For this reason, the defect on the side surface S, for example, the defect (A) located near the outside of the double concentric circle at the time of imaging on the front surface side appears so as to be located near the inside of the double concentric circle at the time of imaging on the back surface side. Conversely, the defect (B) located near the inner side of the double concentric circle at the time of imaging on the front surface side appears to be located near the outer side of the double concentric circle at the time of imaging on the back surface side. Note that the defect of the side surface S appears in the front side image “1F” and the back side image “1B” in the same manner in other test images described later.

  Further, the test image shown in FIG. 6 has a chip defect on the side surface S of a white tablet having the same size as that of sample number 1 as an example. Here, the defects (A), (B), (C) of the front side image “2F”, the back side image “2B”, and the side view image “2S” are the same.

  Furthermore, the test image shown in FIG. 7 has a black spot defect on the side surface S of a yellow tablet having a diameter of about 8 mm and a thickness of about 6 mm as an example. Here, the defects (A) and (B) of the front side image “3F”, the back side image “3B”, and the side view image “3S” are the same. Incidentally, this yellow tablet is thicker (thickness) than the white tablets of sample numbers 1 and 2 above.

  Further, the test image shown in FIG. 8 has a chip defect on the side surface S of a yellow tablet having the same size as the sample number 3 as an example. Here, the defects (A), (B), (C), and (D) of the front side image “4F”, the back side image “4B”, and the side view image “4S” are the same.

  Further, the test image shown in FIG. 9 is an image of the tablet W of sample number 1, that is, “tablet (white) 1”, with the focus of the camera unit 2 slightly changed. The test image shown in FIG. 10 is an image of the tablet W of sample number 2, that is, “tablet (white) 2”, with the focus of the camera unit 2 slightly changed. Furthermore, the test image shown in FIG. 11 is an image of the tablet W of sample number 3, that is, “tablet (yellow) 3”, with the focus of the camera unit 2 slightly changed. The test image shown in FIG. 12 is an image of the tablet W of sample number 4, that is, “tablet (yellow) 4”, with the focus of the camera unit 2 slightly changed.

  When these are compared, for example, in the case of a black spot defect (sample number 1) of a white tablet W having a relatively thin thickness (wall thickness), the visibility of the defect is that of an image in which the width of the side portion is wide (FIG. 5). It is easier to see, or it seems to be the same level in FIGS. Further, in the case of a chip defect (sample number 2) of the tablet W, an image with a narrow side surface (FIG. 10) tends to be somewhat easier to see because the defect is captured as a clear white color on the image. (Especially a chip defect (B)). Furthermore, in the case of a black spot defect (sample number 3) of a relatively thick (thickness) yellow tablet, an image in which the width of the side surface portion is wide (depending on the brightness on the image of the side surface portion). Figure 7) seems to be easier to see. In addition, in the case of a chip defect (sample number 4) of the tablet W, it seems that an image having a narrow side portion (FIG. 12) tends to be easier to see (particularly, a chip defect (B)).

  Therefore, even if the tablet W is relatively thick (wall thickness) or the inspection items are different, the entire side S of the tablet W is adjusted by adjusting the focus accordingly. The image can be taken clearly around the circumference. Note that the viewability of the above-described defect is the view when the captured image is viewed with the eyes (naked eye) as it is, and in fact, such image data can be further processed by a computer ( For example, it is conceivable that even an image that is difficult to distinguish by human eyes can be easily distinguished by computer processing.

  Further, the image shown in FIG. 13 is a test image obtained by taking an image of the tablet W having a black spot defect by applying the cone side mirror 23 (prototype). FIGS. (A) and (b) of FIG. It is the image which imaged the yellow tablet and the white tablet. In these images, the tablet W (main imaging surface M) is shown in the center, and the image of the side S is shown all over the outer periphery, where black spot defects are shown. I can see that. The reference form of the special optical unit 3 related to the present invention to which the cone side mirror 23 is applied as described above can also capture the entire side surface S simultaneously with the main imaging surface M.

  FIG. 14 shows a front side image and a back side image obtained by imaging a tablet W having a substantially triangular shape in plan view, and (A), (B), and (C) in the figure represent black spot defects. FIG. 15 shows a front side image and a back side image (both sides are one side) obtained by imaging a tablet W having a substantially elongated or spindle shape. From these test images, it can be seen that the side S can be imaged all around the main imaging surface M even when the tablet W is not substantially circular.

Thus, in the present invention, since the side surface S is imaged simultaneously with the main imaging surface M, the surface inspection of the tablet W can be performed with only two images of the front side image and the back side image. The enormous amount of information required for the determination can be greatly reduced, and even the inspected object W that performs 100% inspection like the tablet W can perform inspection with extremely high efficiency and high accuracy. Can do. Further, since the inspection of the side surface S can be performed twice with the two images of the front side image and the back side image, the accuracy of the inspection can be further increased and the reliability of the determination can be further improved.
[Other Examples]

  The present invention is based on the embodiment described above as a basic technical idea, but the following modifications can be considered. That is, in the embodiment described above, by holding the tablet W by air adsorption, the tablet W is sent to the imaging unit 6 (camera visual field AR) in a substantially vertical posture, and images are taken from both sides. . However, the tablet W can be transported in various ways, and an appropriate imaging mode can be employed. Specifically, for example, after placing the tablet W on a transparent plate, it is possible to first image the front side from above, and then invert the tablet W to image the back side. In such a case, a transport device having a reversing mechanism is required, but only one camera unit 2 is required for one tablet W. Further, if the object W to be inspected is a tablet W that is easy to roll, for example, as shown in FIG. 16, while rolling on the inclined surface K by using gravity, the front side and the back side are viewed from the horizontal direction. It is also possible to perform imaging. In this case, the inclined surface K may be formed using a transparent material such as glass or acrylic so as to have a slit having a thickness of the tablet W, and the tablet W may be inserted between the slits and slid down.

  Further, when transporting the tablet W to the imaging unit 6, for example, as shown in FIGS. 17 and 18, the tablet W can be transported using a rotating drum 43. In this case, for example, since the front side and the back side can be imaged while the tablets W are adsorbed and transferred to the surface of the rotating drum 43, here, the two rotating drums 43 are provided in a circumscribed state, and the tablet is formed at the contact portion. W is transferred (replaced). When the two rotating drums 43 are distinguished from each other, they are referred to as a vacuum drum 43F and a vacuum drum 43B. That is, the vacuum drum 43F is a front side imaging drum corresponding to the front side imaging conveyor 28F, and the vacuum drum 43B is a back side imaging drum corresponding to the back side imaging conveyor 28B. Due to such a configuration, suction holes 44 for adsorbing tablets W are formed on the drum surface. Here, as an example, five rows of suction holes 44 are formed along the rotation axis of the rotary drum 43, and Tablets W are transported and imaged five at a time.

  In addition, adsorption | suction of the tablet W is performed in a suitable angle range, and hereafter, an example of this mechanism is demonstrated roughly. For example, a suction path 45 along the rotation axis of the drum is formed inside the rotary drum 43, and suction holes 44 (here, five) in the same row formed in the longitudinal direction of the drum are connected thereto. The suction path 45 is closed at one end side and opened at the other end side so as to penetrate to the end of the rotating drum 43, and a non-rotating suction body 46 is fixedly installed at the opening end side. The suction body 46 is formed with a suction groove 47 that acts on the opening side of the suction passage 45 at an appropriate angle. With such a configuration, the suction body 46 continuously sucks during operation. Also, the suction action is caused only in the suction passage 45 (suction hole 44) that enters the area of the suction groove 47.

  In the above-described embodiment, the defective product discharge gate 32 is provided only at the end of the transport conveyor 28, and the tablet W that has become NG in the inspection of the front side image or the back side image is transferred to the end of the transport line. It was a form that discharged together. This is based on the premise that the tablets W being conveyed are synchronized, that is, the tracking control of the tablets W is accurately performed. However, for example, when it is difficult to synchronize the tablets W due to the shape or the conveyance form of the tablets W, that is, when it is difficult to feed the tablets W with substantially the same pitch, the same timing, and the same posture, the front side After the image inspection and the back side image inspection, it is possible to provide a discharge gate 32 for defective products.

  Furthermore, in the embodiment described above, the determination of the tablet W was completely divided into either a non-defective product or a defective product. However, depending on the inspection item (contents), it is difficult to discriminate between non-defective products and defective products. In such a case, a so-called re-inspection product discharge gate 32 is provided, and for the re-inspection product, it is possible to leave the final judgment to, for example, a visual inspection of an operator who has mastered the inspection.

  In the above-described embodiment, the disk-shaped tablet W is mainly described as an example of the inspected body W (see FIG. 19A), but the inspection target is limited to the disk-shaped tablet W. For example, as shown in FIGS. 19B and 19C, the tablet W may be relatively unsuitable for rolling, such as a substantially triangular shape or a substantially square shape, or FIG. 19D. As shown in Fig. 5, a tablet W having an elongated shape or a spindle shape can be used as an inspection object. Incidentally, in the test conducted by the present applicant, the side surface S is the front surface F (back surface B) of the substantially triangular tablet W or the elongated tablet W by the special optical unit 3 having the convex lens 13 as a main member. It has been confirmed that imaging can be performed simultaneously (see FIGS. 14 and 15).

  Moreover, as a reference form of the inspected object W related to the present invention, for example, a prismatic member or a columnar member as shown in FIG. 20A, a truncated pyramid member or a cone as shown in FIG. A solid member such as a trapezoidal member or a pyramidal member or a conical member as shown in FIG.

It is a perspective view which shows an example of the tablet inspection system of this invention. It is explanatory drawing (a) which shows an example of the imaging device which image | photographs a direct-view surface and a non-direct-view surface simultaneously, and explanatory drawing (b) which shows the front side image and back side image in case a cube is a to-be-inspected object. It is a perspective view which shows the reference form of the special optical part relevant to this invention using a cone side mirror. It is explanatory drawing which showed gradually a mode that the front side and back side of a tablet were imaged alternately, conveying a tablet in the state stood substantially perpendicularly. It is the photograph image (sample number 1) which imaged each white tablet with a black spot defect from the front side, the back side, and the side. It is the photograph image (sample number 2) which imaged the white tablet with a chip defect from the front side, the back side, and the side, respectively. It is the photograph image (sample number 3) which imaged each yellow tablet with a black spot defect from the front side, the back side, and the side. It is the photograph image (sample number 4) which imaged the yellow tablet with a chip defect from the front side, the back side, and the side, respectively. It is the photograph image of the front side and back side which imaged the tablet of the said sample number 1 changing focus. It is the photograph image of the front side and back side which imaged the tablet of the said sample number 2 changing focus. It is the photograph image of the front side and back side which imaged the tablet of the said sample number 3 changing focus. It is the photograph image of the front side and back side which imaged the tablet of the said sample number 4 changing focus. It is the photographic image which imaged the tablet by applying a cone side mirror. It is the photograph image of the front side and back side which imaged the tablet which comprises a substantially triangular shape in planar view. It is the photograph image of the front side and back side which imaged the substantially elongated tablet. It is a perspective view which shows the form which imaged the front side and the back surface of a tablet while rolling on an inclined surface. It is explanatory drawing which shows the conveyance form of the tablet to which a pair of rotation drum is applied. It is a perspective view which shows the conveyance form of the tablet to which a pair of rotation drum is applied. It is explanatory drawing which shows the various shapes of the tablet which can become a test object. It is a perspective view which shows the reference form of the to-be-inspected object relevant to this invention. It is a perspective view which shows various conventional methods of carrying out imaging inspection of all the tablet surfaces.

1. Imaging device (imaging device that captures both direct and non-direct viewing surfaces)
2 Camera unit 2F Camera unit (for front side imaging)
2B Camera unit (for back side imaging)
DESCRIPTION OF SYMBOLS 3 Special optical part 4 Illumination part 6 Imaging part 7 Conveyance part 8 Image processing part 11 CCD area sensor camera 12 Lens 12a Close-up ring 13 Convex lens 14 Synchronous sensor 15 Side ring illumination 16 Coaxial epi-illumination 17 White LED (side side)
18 Half mirror 19 White LED (coaxial side)
20 Color filter 23 Cone side mirror 23A Cone side mirror (inside)
23B Cone side mirror (outside)
26 Quantitative supply device 27 Alignment device 28 Transport conveyor 28F Front side imaging conveyor 28B Back side imaging conveyor 29 Hopper 30 Supply conveyor 31 Cylindrical member 32 Discharge gate 35 Image computer 36 Host computer 37 Monitor 38 Keyboard 39 Mouse 40 Video switcher 43 Rotating drum 43F vacuum drum (for front side imaging)
43B vacuum drum (for back side imaging)
44 Suction hole 45 Suction path 46 Suction body 47 Suction groove A Tablet inspection system AR Camera view B Back surface C Camera D Lower side surface F Front surface K Inclined surface M Main imaging surface NV Non-direct viewing surface S Side surface T Turntable U Upper side surface V Direct view surface W Tablet (inspection object)

Claims (6)

An imaging unit (6) for imaging the surface of the tablet (W) to be taken, a transport unit (7) for sending tablets (W) to the imaging unit (6) one by one, and taking the captured images on the tablet surface An image processing unit (8) for determining whether there is a defect such as a chip or a foreign object, and a system for inspecting and determining whether the tablet (W) is good or bad,
The imaging unit (6) includes a special optical unit (3) mainly including a convex lens (13) and an illumination unit (4) for illuminating a tablet (W) to be inspected (W) . The camera unit (2) is a main component, and the camera unit (2) images the surface of the tablet (W) .
Also, the camera unit (2) is a convex lens (13), tablets front surface of the (W) (F) or rear surface (B) provided so as to face the tablets front surface of the (W) (F) Or the back surface (B) is the main imaging surface (M) ,
When imaging the tablet (W), the illumination unit (4) causes both the main imaging surface (M) as the direct viewing surface (V ) and the side surface (S) as the non-direct viewing surface (NV) of the tablet (W). While illuminating the light, the main imaging surface (M) and the side surface (S) of the tablet (W) are imaged almost entirely,
In addition, for the side image of the tablet (W) , taking into account that the entire outer periphery of the main imaging surface (M) is imaged with a substantially constant width and includes more aberration toward the outer side, during front side imaging and back side imaging The side (S) of the tablet (W) is imaged twice in
In determining whether the side of the tablet is good or not, the image data on the front side (F) and the side (S) taken at the same time, and the back side (B) and the side (S) taken simultaneously on the back side are taken. A tablet inspection system characterized in that a tablet (W) having no defect in both image data and image data is judged as a non-defective product .
2. The tablet inspection system according to claim 1, wherein the camera unit (2) images a defect having a minimum size of about 60 [mu] m.
The tablet inspection system according to claim 1 or 2, wherein the camera unit (2) is one-shot imaging that images the tablet (W) once in an extremely short time.
The conveying section (7), the tablets upright substantially perpendicularly (W), according to claim 1, 2 or 3, wherein the is intended to convey as it posture to the imaging unit (6) Tablet inspection system .
The transport unit (7) includes a transport conveyor (28) having a transport surface formed substantially vertically, and the tablet (W) has a front surface (F) or a back surface (B) adsorbed to the transport surface, thereby 5. The tablet inspection system according to claim 4 , wherein the tablet inspection system is sent to the imaging unit (6) in a state where (W) is raised.
The conveying section (7), tablet inspection system according to claim 1, 2, 3, 4 or 5, wherein the aligned so tablets (W), is to transfer at substantially the same pitch and timing .