JP2010256313A - Seal defect inspection apparatus of light shielding thermal seal wrapping material and method of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To overcome a difficulty in an image inspection, due to a warpage and a bend of a retort pouch. <P>SOLUTION: A seal defect detector 1 of the pouch 2 is provided with: a carrying section 3 for carrying the pouch 2 filled with a filler; a first illuminating section 4 disposed on one side of the carrying section 3, and obliquely and downwardly illuminating the pouch 2 in the first direction X so set as to cross the carrying section 3; a first imaging section 5 for imaging a seal section 2a when the seal section 2a of the carried pouch 2 passes through the first illuminating section 4; a second illuminating section 6 disposed on the downstream side of the first illuminating section 4 in the carrying direction, and illuminating the pouch 2 in the second direction Y axisymmetric to the first direction X relative to a vertical line; a second imaging section 7 for imaging the seal section 2a when the seal section 2a of the carried pouch 2 passes through the second illuminating section 6; a seal defect detecting section 8 for processing images captured by the first and second imaging sections 5, 7, and detecting seal defects in the images; and a discharging section 9 for discharging the corresponding pouch as a defective product. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a seal failure inspection apparatus method for detecting a seal failure in a seal portion in which a filling port is heat-welded after filling a content in a heat seal packaging material and the method.

  In heat-sealing packaging materials that hermetically wrap foods with fluidity, etc., after filling the required filling material in a heat-sealing packaging material that is sealed (sealed) on three sides, the filling port is hermetically sealed (sealed) )is doing. In this sealing process, there may be a sealing failure on the heat-welded surface (seal surface) such as a seal flaw, pinholes, air bubbles, contamination, and water droplet adhesion due to filling vapor due to poor adhesion. Since such a sealing failure causes decay of the filling, it is necessary to reliably determine the presence or absence of the sealing failure after the filling process.

  First, there is an inspection apparatus called a leak tester that puts a heat seal packaging material into a chamber, depressurizes the air in the chamber, and detects a seal failure by a pressure difference before and after the depressurization. This is a device for inspecting the heat-sealed packaging material without conveying it. First, put a package to be inspected such as a glass or plastic sealed container in a confidential chamber with a perforated window that can be optically visualized and observed by the shadow graph method, Schlieren method, etc. Then, there is an apparatus that optically observes an airflow ejection state of a package to be inspected, inspects an image, compares states before and after decompression, and automatically inspects a defective state (Patent Document 1).

  Next, a sealed body filled with the contents in advance is put in the chamber to generate a differential pressure between the pressure inside the sealed body and the pressure in the chamber, and the contents or oxygen contained in the chamber is sealed. There is a sealing body leakage inspection method characterized in that it is detected in a chamber internal space outside the body or guided from the space, and the presence or absence of leakage of the sealing body is determined based on the concentration difference (Patent Document 2).

.
Next, there is an electrostatic seal defect inspection device that inspects a defective seal while conveying a heat seal packaging material (Patent Documents 3 to 5). This is to inspect the defective portion by detecting the total thickness of the portion where the thermal welding is defective. That is, this seal failure inspection device is applied to a heat-sealing packaging material in which a plurality of types of sheet members including a conductive layer are laminated and a heat-welding sheet member is disposed inside the conductive layer on the opposite surface, respectively. Each distance between the conductive layer and each detection electrode is measured from each capacitance between each conductive layer of the heat seal wrapping material, and conduction is determined from these distances and the distance between the two detection electrodes. In this method, the thickness between the sex layers is calculated, and if the calculated thickness is equal to or greater than a predetermined value, it is detected that the heat-sealed packaging material is determined to have a sealing failure.

  There is a defect inspection method using a pinhole checker (Patent Documents 6 and 7). This is a voltage-applied high-speed line sensor that detects non-destructively pinholes and seal defects in resin-packaged products such as conductive foods and pharmaceuticals using infrared temperature distribution difference images. Since it is a method that detects the flow of electrons, it can inspect minute pinholes that allow bacteria to enter at high speed.

The sealing failure inspection device for heat seal packaging material performs extraction processing of a binarized image of the retort pouch 2 to be inspected (S1), identifies a portion surrounded by an outline as a defective region (S2), and determines the defective image as an area. was measured to determine the total area S (S3), determines whether the total area S exceeds the reference area S ₀ (S4), it generates a corresponding defective discharge command signal positive determination at S4, the discharge It outputs to the apparatus 10 (S5) and discharges defective products. The contact inspection device 14 applies a voltage to the subject while continuously contacting the surface of the retort pouch 2 that is the subject passing through the first electrode 11 with the second electrode 12 receiving the applied voltage. There has been proposed an invention for detecting and inspecting pinholes and other seal failures by capturing electrical changes in the circuits constituting them (Patent Document 8).

JP-A-63-273031 JP-A-10-185552 JP-A-6-345062 JP-A-7-120426 JP-A-8-301241 JP 2000-88781 A JP 2000-227407 A JP2005-241302

However, Patent Documents 1 and 2 require a large apparatus for gas pressure control, and Patent Document 1 complicates image inspection and makes it difficult to perform simple inspection. In addition, the leak tester, Patent Documents 1 and 2, and the pinhole checker inspect the inspection object without conveying it, so the inspection efficiency is poor. Furthermore, the electrostatic heat seal packaging material inspection apparatus can be applied to conductive heat seal packaging materials, but cannot be applied to inspection of insulating heat seal packaging materials (for example, transparent plastic materials) (patent) Literature 3-6). Since patent document 7 is infrared rays, there exists a problem that an application range is narrow. In Patent Document 8, the inspection efficiency and accuracy are good, but in the case of light-shielding heat-sealing packaging materials such as aluminum retort packs and laminate pouches, the aluminum surface is light-shielding and detects reflected light, resulting in poor heat sealing. Although the inspection is being performed, there are situations where the direction of the reflected light changes due to warpage, undulation, unevenness, etc. on the surface of the packaging material, resulting in a difference in brightness, which makes it difficult to capture images. Therefore, although the bright part of the image can be processed, the shadow part cannot be processed, and there is a problem that the inspection omission cannot be overcome.
In particular, when a packaging material or liquid bite occurs, bacteria are transmitted from there and enter the contents to rot the contents, so that it is desired to effectively eliminate the defective seal.

  In view of the above points, the present invention realizes a simple and cost-effective inspection method and inspection apparatus in seal defect inspection by image inspection of a light-shielding heat-sealing packaging material made of a material that reflects light such as an aluminum retort pack. This is a problem.

  In view of the above problems, the invention according to claim 1 is configured such that a light-shielding heat-sealing packaging material filled with a filling material is conveyed, and the heat-sealing packaging material is disposed on one side of the conveying portion from above obliquely. A first illumination unit that illuminates from a first direction that is set to cross the conveyance unit, and the seal portion of the heat-sealed packaging material that is being conveyed images the seal unit when passing through the first illumination unit The first imaging unit and the first illumination unit are arranged on the downstream side in the transport direction, and the heat seal packaging material is illuminated from a second direction set symmetrically with respect to the first direction and a vertical line. A second illumination unit that performs imaging, a second imaging unit that images the seal unit when the seal unit of the heat-sealed packaging material being conveyed passes through the second illumination unit, and an image that is captured by the imaging unit A seal failure detection unit that detects a seal failure in the image and A discharge portion for discharging the appropriate heat sealing packaging material as a defective product, is sealed fault detection apparatus of heat-seal packaging material, characterized in that it comprises a. Thereby, the said subject can be solved suitably.

  The light-shielding heat-sealing packaging material mentioned here includes airtight and light-shielding materials such as retort pouches such as retort foods, pharmaceuticals, and chemicals. A pouch is generally made of a laminated film made of synthetic resin or aluminum foil, and is a laminated film made of laminated PP / AL / PET (polypropylene sheet, aluminum sheet and two layers of polyethylene terephthalate sheet). is there. It is a device for blocking air, moisture and light and sealing foods inside.

  The sealing failure here includes no bottom opening, bending, position failure, biting, wrinkles and the like. In particular, it is preferable to detect biting of the contents.

  The invention according to claim 2 is set so that the heat-sealing packaging material is traversed from the diagonally upward direction while the light-shielding heat-sealing packaging material is filled and sealed by heat sealing. A first imaging step of imaging the seal portion of the heat-sealing packaging material while illuminating from the first direction; and after being imaged in the first imaging step and conveyed downstream from the imaging position, the heat-sealing packaging material is A second imaging step of imaging the seal portion of the heat-sealing packaging material while illuminating from a second direction set symmetrically with respect to the first direction and a vertical line; the first imaging step and the second imaging step A processing step for processing an image picked up in step, a determination step for detecting a sealing failure with reference to the processed image, and a discharging step for discharging the corresponding heat seal packaging material as a defective product, A sealing failure detecting method of the light-shielding heat sealing packaging material, characterized in that it comprises a.

  According to the first and second aspects of the present invention, the lightness difference caused by the reflection of illumination light caused by warpage, unevenness, wrinkles, bending, etc. on the surface of the packaging material is overcome, and it is not affected by poor photographing. Inspection accuracy and inspection efficiency can be greatly improved.

  A light-shielding heat seal packaging material seal failure detection device 1 (hereinafter simply referred to as a seal failure inspection device) is a retort food pouch 2 (hereinafter referred to as a pouch 2) that is a light-shielding heat seal packaging material filled with a filler. .), A first illumination unit 4 that is arranged on one side of the conveyance unit 3 and illuminates the pouch 2 from a first direction X set across the conveyance unit 3 obliquely from above. The first imaging unit 5 that images the seal unit 2a when the seal unit 2a (see FIG. 2) of the pouch 2 that passes through the first illumination unit 4 is disposed on the downstream side in the transport direction of the first illumination unit 4 In addition, the second illumination unit 6 that illuminates the pouch 2 from the second direction Y that is set symmetrically with respect to the first direction X and the vertical line, and the seal unit 2a of the pouch 2 being conveyed are second. 2nd image picking up image of seal part 2a when passing illumination part 6 Processing unit 7, images picked up by first image pickup unit 5 and second image pickup unit 7, seal failure detection unit 8 for detecting a seal failure in the image, and discharging the corresponding heat seal packaging material as a defective product And a discharge unit 9 that performs the above operation. In addition, an electrical control panel 11 that communicates bidirectionally with the seal failure detection unit 8 to control electrical control, an operation panel 12 connected to the seal failure detection unit 8 and the electrical control panel 11, and a photoelectric sensor that detects passage of the pouch 2. 13, an image processing encoder 14 that detects the position of the imaging timing, a discharge position encoder 15 that detects the position of the discharge timing, a connected pouch discharge nozzle 16 that performs a discharge operation when the pouch 2 is detected to be connected, and A liquid leakage detection sensor 17 is provided. Hereinafter, each element will be described in detail.

  This sealing failure inspection apparatus 1 inspects a pouch 2 which is a light-shielding and air-tight heat-sealing packaging material including a metal sheet (aluminum foil or the like) as a subject as a constituent element. The pouch 2 for determining whether or not there is a sealing failure is a pre-made bag-like one in which a predetermined number of sheet members are laminated and are air-tightly bonded in advance leaving only one of the contents. After filling, the other one is heat-treated with a heat bar or the like, and the opening is thermally welded to be sealed. The pouch 2 here is mainly a retort pouch, but includes other forms. Examples of the sealing failure in the embodiment include no bottom opening, bending, position failure, biting, and wrinkles. The pouch 2 may be, for example, an outer dimension of W110 mm × H140 mm. The inspection capability is set to, for example, 80 pieces / minute (up to 150 pieces). The pouch 2 transported by the transport unit 3 is illuminated obliquely from above by the first illumination unit 4 and the second illumination unit 6, respectively, and a seal inspection is performed based on images captured by the first imaging unit 5 and the second imaging unit 7. I do. Based on the image from the diagonally upward left side and the image from the diagonally upward right side with respect to the conveyor traveling direction, biting or breaking of the seal portion is detected to determine pass / fail, and the pass / fail determination result is output. Thereby, the stable test | inspection can be performed, without being influenced by the curvature and bending of the seal | sticker part 2a.

  As shown in FIGS. 1 to 3, the transport unit 3 includes a belt conveyor 30 that transports the pouch 2 and that is anti-slip processed, a support unit 31 that supports the belt conveyor, and a drive motor 32. is there. The conveyance speed is set so that the pouches 2 conveyed by the conveyance unit 3 are inspected at 80 pieces per minute (1.3 pieces per second).

  Note that the pouch 2 is supplied to the transport unit 3 from a feeder (not shown) arranged on the upstream side.

  As shown in FIG. 1 to FIG. 4A, the arrangement of the first illumination unit 4 and the second illumination unit 6 is one of the characteristic configurations. The two illumination units 4 and 6 are transported by the transport unit 3. The positions are biased back and forth along the direction C, and complementary illumination from the left and right by these two units is configured. First, the 1st illumination part 4 is installed in the side surface right side of the conveyance part 3 toward the conveyance direction C downstream, and it illuminates in the 1st direction X. The first illumination unit 4 includes a plurality of light emitters 40 formed of LEDs (may be halogen lamps), a casing 41 that fixes the light emitters 40 and that has an opening on the transport unit 3 side, And a fixture 42 to which the casing 41 is attached. As shown in FIG. 4A, the light emitter 40 is mounted so that the body axis is at an inclination angle θ with respect to the horizontal, and the body shaft mounting angle α of the casing 41 is (90 ° − θ).

  In addition, the second illumination unit 6 is disposed at a predetermined distance downstream from the first illumination unit 4 in the transport direction C, and is disposed on the left side surface toward the downstream in the transport direction C, and illuminates in the second direction Y. To do. The second illumination unit 6 includes a light emitter 60, a casing 61 having an opening formed on the cylindrical conveyance unit 3 side that fixes the light emitter 60, and a fixture 62 to which the casing 61 is attached. The Similar to the first illumination unit 4, the light emitter 60 is attached at an inclination angle θ, and the axis of the casing 61 is provided with an attachment angle α, which is (90 ° −θ).

  The inclination angle θ is preferably set in the range of 25 to 45 ° according to the type of the pouch 2 and the like. In the figure, the inclination angle θ is set to 30 degrees and α is set to 60 degrees. The mounting angles of the casings 41 and 61 can be changed.

  A first illuminating unit 4 'and a second illuminating unit 6' in the modified form shown in FIG. 4B are also possible. In this modification, both the body axes of the light emitters 40 ′ and 60 ′ and the axial direction of the casings 41 ′ and 61 ′ have an inclination angle θ.

  The light emitters 40 and 60 of the first illumination units 4 and 6 may be single or plural, surface light emission, or point light emission. The first illumination unit 4 and the second illumination unit 6 are preferably a halogen lamp, a light emitting element (LED), or an infrared light emitting element (IR-LED). In the case of a halogen lamp, since it includes infrared rays, it can be used for both black-and-white photography and infrared photography. On the other hand, in the case of an LED, infrared light is not emitted unless it is an IR-LED. is there. Although direct illumination is preferred, indirect illumination may be used.

  The reason for illuminating from two symmetrical directions obliquely above the side of the transport unit 3 is to make it easier to detect biting such as vertical streaks entering the seal portion 2a of the pouch 2. In FIG. 2, it is exemplified that light is emitted from the first illumination unit 4 and the second illumination unit 6 to the pouch 2 in a direction orthogonal to the conveyance direction C of the pouch 2, but the angle is changed from 90 °. The angle is appropriately set according to conditions such as providing.

  If color printing is included on the inspection surface, processing at the lightness level becomes difficult, so it is preferable to erase the color by infrared imaging. That is, black and white photography is preferred when there is no color printing, and infrared illumination photography is preferred when there is color printing. The illumination is preferably a halogen or an LED, but when performing infrared imaging, the LED is preferably an IR-LED.

  The first imaging unit 5 includes a black and white area camera fixed to the upper part of the transport unit 3, and the shooting direction is set vertically downward. The first imaging unit 5 is fixed next to the first illumination unit 4 with respect to the transport direction C. Further, as shown in FIG. 2, the second image pickup unit 7 is installed at the same height as the first image pickup unit 5 and is located at an upper portion of the transport unit 3 at a position separated by a predetermined distance downstream (for example, at intervals of 4 cm to 15 cm). The black and white area camera is fixed to the camera, and the shooting direction is set vertically downward. A line connecting the first imaging unit 5 and the second imaging unit 7 is parallel to the conveyance direction C. Further, the second imaging unit 7 is fixed next to the second illumination unit 6 with respect to the transport direction C. The first imaging unit 5 and the second imaging unit 7 are progressive scan systems and are area sensors. The camera may be either a black and white camera or a color camera, but normally a black and white camera is used. The detection resolution capability of the camera is 0.2 to 0.25 mm / pixel, which is 640 × 480 pixels, and a field of view of about 160 mm is observed on the conveyor, but is not limited thereto. The pouch 2 that flows at about 57 m / min under the camera is imaged with an electronic shutter in 1/1000 second, the image is captured in about 0.03 second, and the appearance is measured within about 0.3 second. The two cameras are IR-LED illuminated separately on the left and right sides and attached at intervals of about 0.5 seconds, and when the two measurements on the left and right are finished, the captured images are output. Examples of imaging are shown in FIGS. As shown in these drawings, the image captured by the first imaging unit 5 on the right side and the image captured by the second imaging unit 7 on the left side supplement each other's dark portions. As a result, appropriate imaging can be performed even if the seal portion 2a has swell or warpage.

  The seal failure detection unit 8 shown in FIG. 5 performs binarization processing on the image signals imaged and created by the first imaging unit 5 and the second imaging unit 7, and the binarized image has a predetermined reference regarding the inspection region. Those that do not satisfy the above are determined as poor seals. As shown in FIG. 6, the seal failure detection unit 8 is a microcomputer that controls processing of image signals from the imaging unit 5 and the imaging unit 7, and includes a CPU 80, a RAM 81, a ROM 82, a counter 83, a timer 84, a hard disk, and the like. A storage device 85 and an input / output interface 86 are connected to each other by a bus 87. The seal failure detection unit 8 normally inputs a black and white image from the imaging units 5 and 7 and binarizes it, but receives R, G, and B (red, green, and blue luminance) signals from the imaging units 5 and 7. It may be input and black and white binarized. Then, the presence / absence of a seal failure is determined according to a predetermined determination criterion, a failure discharge command signal is transmitted to the discharge unit 9 with reference to this determination data, and defective products are selectively discharged. The discharge unit 9 receives the defective discharge command signal from the seal failure detection unit 8, and in response to the signal, the discharge unit 9 discharges the corresponding pouch 2 at the defective discharge point.

  The seal failure detection unit 8 incorporates an image capture board (not shown). The image processing unit makes a pass / fail determination by inspecting the biting or bending of the seal portion at the top of the retort pouch. Illumination from different angles on the left and right sides can avoid the influence of warping or bending of the seal portion. By using infrared light, a stable inspection can be performed regardless of the pattern of the pouch 2. Clearly printed black characters are masked out of the inspection range.

  A predetermined inspection standard for performing an appearance inspection by image analysis processing is set. In addition, product-specific parameters are arbitrarily set. As the seal inspection items, it is determined whether or not “seal breakage”, “sealing tool / foreign matter biting”, “seal position”, “wrinkle of adhesive part”, “bottom opening failure”. Mainly for biting, other inspection items can be omitted as appropriate.

(1) No bottom opening When there is no bottom opening, the side of the seal part 2a of the pouch 2 is inspected for dents. This utilizes the property that when the bottom of the pouch 2 is not sufficiently open, the contents are concentrated and forcibly packed in the vicinity of the center of the pouch 2 so that the side surface is distorted. When there is a dent exceeding the reference value (horizontal width) on both the left and right sides, and when there is a dent exceeding the reference value over a wide range on either the left or right side, it is detected that there is no bottom opening. The reference value (horizontal width) can be changed on the setting screen as an auxiliary parameter.

(2) Folding Folding is detected when there is a difference greater than the reference value (bending amount) by examining how far the unevenness on the top of the pouch 2 is from the reference position. At this time, since R (R) is attached to both left and right ends, it is necessary to exclude this portion from the bending inspection. For this reason, a fixed range (folding range offset) is not inspected from the left and right ends. The reference value (folding amount) can be changed from the operation panel 12 as a basic parameter, and the fixed range (folding range offset) can be changed from the setting screen as an auxiliary parameter.

(3) Poor position For the poor position, first measure the seal position and hook hole position, and inspect the distance from the top of the pouch 2 to the center of the seal and the distance from the bottom of the hole to the center of the seal. When the difference between the distance from the upper end of the pouch 2 to the seal and the reference value (seal position) exceeds the reference error (seal position error), a position failure is detected. If the upper hole can be measured, the distance from the lower end of the hole to the center of the seal is also compared with the reference value (hole position), and if it is less than the reference value (hole position), it is detected as a position defect. Furthermore, when the seal part 2a cannot be measured accurately, it is detected as a position defect. The reference value (seal position) can be changed from the operation panel 12 as a basic parameter, and the reference value (hole position) and reference error (seal position error) can be changed as auxiliary parameters from the setting screen.

(4) Biting Biting measures the periphery of the seal position measured in the position defect inspection, and inspects the thickness and continuity of the seal portion 2a.

(5) 皺 皺 identifies the upper / lower shade difference from the seal position measured in the position defect inspection, and is detected when the shade of shade exceeds the reference value (皺 detection size). The reference value (wrinkle detection size) can be changed from the operation panel as a basic parameter.

  The parameters of the seal inspection item will be described.

(1) Folding amount Judge that the unevenness at the top edge is severe. The tolerance of this unevenness is specified in mm as the amount of bending. If the fold amount threshold is lowered too much, the distortion of the pouch 2 and noise during photographing may be erroneously detected as folds. If the threshold is raised too much, there is a possibility of overlooking an external abnormality that should be recognized as a fold.

(2) Biting level Adjust the level of contrast for recognizing the seal part. Decreasing the threshold value of the difference in density reduces the recognition of the seal, and increasing the threshold value makes it difficult to recognize.

(3) Seal position Set the position of the center of the seal position from the top of the pouch 2 in mm.

(4) Wrinkle detection size In the wrinkle inspection, the difference in shading is detected, and the size is judged to be acceptable. When the threshold value is lowered, the recognition of wrinkles becomes severe, and when the threshold value is lowered, the recognition becomes sweet.

  When the seal part 2a of the pouch 2 is a color, a visible light cut filter is attached to the image pickup part 7 to cut visible light into a black-and-white image using only infrared rays, which may be converted into a binary image.

  The discharge unit 9 is composed of an air cylinder or the like, and can discharge the pouch 2 that is poorly sealed at a defective discharge point.

  The electrical control panel 11 shown in FIG. 5 includes a transport unit 3, a first illumination unit 4, a first imaging unit 5, a second illumination unit 6, a second imaging unit 7, a discharge unit 9, a photoelectric sensor 13, and an image processing encoder. 14, connected to the connected pouch discharge nozzle 16 and the tool / liquid leak detection sensor 17, and bidirectionally connected to the seal failure detection unit 8 so that various input signals and output signals can be input and output. ing.

  The touch panel type operation panel 12 performs general operations such as starting and stopping of the inspection apparatus, and is used for storing inspection result data.

  The photoelectric sensor 13 detects the passage of the pouch 2. It is used for detecting the inspection quantity of the pouch 2.

  The image processing encoder 14 is a rotary encoder and measures the moving distance of the pouch 2 from the first imaging unit 5.

  The discharge position encoder 15 is a rotary encoder, and measures the moving distance of the pouch 2 from the second imaging unit 7.

  The connected pouch discharge nozzle 16 discharges the connected pouch 2 by an air blow method.

  The tool / liquid leak detection sensor 17 detects the pouch 1 that has leaked the tool / liquid in advance, and is installed upstream of the transport unit 3 or at the inlet of the apparatus 1.

  As described above, the pouch 2 is illuminated from two directions on the left and right sides, and each is photographed to obtain two images to comprehensively determine a seal failure.

  Next, the operation of the seal defect inspection apparatus 1 will be described. The general operation is as follows. When the pouch 2 is supplied from the feeder (not shown) to the transport unit 3, the pouch 2 is transported in the transport direction C, and the pouch 2 is illuminated with the first illumination unit 4 in the middle of the pouch 2. 2a is imaged by the first imaging unit 5. In addition, the second imaging unit 7 images the seal portion 2 a of the pouch 2 while illuminating the pouch 2 with the second illumination unit 6. The image picked up in this way is binarized by the seal defect detection unit 8, an area corresponding to one of the black and white values in the binarized image is specified, and the seal defect area is determined according to a predetermined criterion. If it is determined that the product is defective, the discharge unit 9 discharges it as a defective product.

  Hereinafter, the details of the image processing by the seal failure detection unit 8 will be described with reference to the flowchart of the image processing shown in FIG. The image inspection program of this embodiment is stored in the ROM 82, and a predetermined image inspection is executed in accordance with a command from the CPU 80.

  First, when processing is started, the CPU 80 performs a series of initial settings such as resetting a counter 83 and a flag. Here, the various count values and the initial value of the flag are both “0”. In the following flowcharts and descriptions thereof, “step” is simply abbreviated as “S”.

  The seal part 2a of the pouch 2 is imaged while illuminating the pouch 2 from the first direction X set so as to cross the conveyance direction C of the conveyance part 3 from obliquely above, and the image is captured (S1).

The position L that has advanced downstream from the imaging position imaged in the first imaging step (S1) is detected based on the image processing encoder 14, and the pouch 2 is conveyed downstream to a position of a predetermined distance L ₀ (15 cm in this case). It is determined whether it has been done (S2). If the determination is negative, the process returns to S1, and if the determination is affirmative, the process proceeds to S3.

  In S3, the seal part 2a is imaged while illuminating the pouch 2 from the second direction Y, and the image is captured (S3).

  Binarization processing is performed on the images captured in S1 and S3 based on a predetermined threshold (S4). Since the background is always white, the external binarization level processes how much whiteness is regarded as the background. When the threshold value of the outer shape binarization level is lowered, the outer shape recognition becomes narrower, and when the threshold value is raised, the outer shape recognition becomes wider. If the threshold is lowered too much, a portion that has become bright due to light diffraction or the like is omitted from the outer shape recognition, and a non-defective product is likely to be erroneously detected as a broken or poor position. If the threshold is raised too much, it will be easier to pick up shooting noise in the vicinity of the outer shape, and it will be easier to falsely detect it as a break.

  Referring to the image processed in S4, a defective image of the binarized image is specified (extraction process), and a process of determining whether or not the seal is defective is performed according to a predetermined standard (S5). . Here, an inspection frame (a frame surrounded by a rectangle in FIGS. 8 and 9) is always provided, and the inspection is performed therein. Even with infrared shooting, the red, green and blue parts can be erased, but the black part cannot be erased. In addition, a portion having a hook hole or the like, a portion having a character, or a pattern portion usually has no influence on the seal. Therefore, it is preferable to mask the portion and remove it from the processing range. In FIGS. 8 and 9, the rectangular frame is a seal location inspection area, and the other is a content filling area (non-inspection area). In FIGS. 8 and 9, the excellent portion is white (“0”), and the defective area is black (“1”) (monochrome may be set in reverse). The seal defect inspection unit 8 displays the inspection result and stores it in the memory.

  Imaging by the first imaging unit 5 and the second imaging unit 7 is performed twice under illumination from line symmetry with respect to the vertical line at different locations. That is, the first imaging unit 5 images the pouch 2 once under the illumination of the first illumination unit 4, and further under the illumination of the illumination unit 6 on the left side surface that is now symmetrical with respect to the vertical line on the downstream side. To take one image. That is, complementary illumination and complementary imaging are performed. Further, since the irradiation inclination angle θ is set from the horizontal to the upper direction in the irradiation direction, the brightness difference is increased and more effective imaging can be performed.

  When the discharge unit 9 receives the defective discharge command signal from the defective seal detection unit 8, the discharge unit 9 discharges the pouch 2 determined to be defective at the defective discharge point (S6). The imaging results of the two images are determined, and the pouch 2 is allowed to pass if there is no seal failure in either the image by the first imaging unit 5 or the image by the first imaging unit 7. When there is a seal failure in either one or both, the defective product discharge cylinder of the discharge unit 9 selectively discharges it as a defective product each time. An air cylinder (not shown) bends a part of the conveyance unit 3 to drop the pouch 2 into a box with a defective seal below.

  Further, when the connection detection setting is made and the pouch 2 is inspected within an interval that can be processed by the seal defect inspection unit 8, it is determined that the connection is abnormal. In the case of the above setting, when a 140 mm pouch passes at a pitch of 200 mm or less (60 mm between pouches), the discharge position detecting encoder 15 discharges two pouches having a narrow interval by the connected pouch discharge nozzle 16 after 630 pulses.

  Inspection result display is performed (S7). The non-defective product is displayed as OK, and the defective product is displayed as “no bottom open”, “break”, “position defect”, “engagement”, and “皺” for each state. An error is displayed if measurement cannot be performed correctly due to poor lighting adjustment, sample rotation, or connection. As the measurement numerical value display, the folding amount of the currently displayed image, the seal position, the maximum wrinkle size, and the like are displayed. When no bottom opening or breakage is detected, the seal position is not displayed because other measurements are difficult.

  An example of the inspection result is shown in FIGS. Samples 1 to 4 show two images when imaged with right-side illumination and when imaged with left-side illumination, and the captured image of the camera and the image of abnormality detected after image processing are shown above and below, respectively. . The inspection result is displayed every time one pouch is inspected, and the number of inspection processes and the number of defects are added. The quantity for each inspection result is added to the inspection result screen. Each time product switching is completed, the inspection result data is stored and one inspection processing number is added. Save test results in memory.

  The preferred embodiments of the present invention have been described above. However, it is needless to say that the present invention is not limited to the above-described embodiments, and many modifications can be made without departing from the technical idea of the present invention. Those skilled in the art will appreciate that additions, substitutions, deletions, and the like can be made.

  According to the present invention, since it is possible to accurately and efficiently inspect a sealing failure such as a light-shielding retort pouch, it is possible to contribute to the inspection of a sealing failure such as a retort pouch. The utility value of the present invention for retort pouches for foods, confectionery, pharmaceuticals, etc. is extremely high.

1 is a front view of a seal defect inspection device 1 according to an embodiment of the present invention. It is also a plan view. It is also the right side. (A) (b) is detail drawing of a 1st illumination part and a 2nd illumination part. It is a block diagram which similarly shows the electric constitution of the sealing defect inspection apparatus 1. It is a block diagram which similarly shows the electric constitution of the seal defect detection part 8. FIG. It is a flowchart of the process which the seal defect detection part 8 similarly performs. It is an image which shows the samples 1 and 2 of the retort pouch image | photographed with the camera and image-processed. It is an image which shows the sample 3 and 4 of the retort pouch image | photographed with the camera and image-processed.

DESCRIPTION OF SYMBOLS 1 ... Seal defect inspection apparatus 2 ... Retort pouch 2a ... Seal part 3 ... Conveyance part 4 ... 1st illumination part 5 ... 1st imaging part 6 ... 2nd illumination part DESCRIPTION OF SYMBOLS 7 ... 2nd imaging part 8 ... Seal defect detection part 9 ... Discharge part 11 ... Electric control panel 12 ... Operation panel 13 ... Photoelectric sensor 14 ... Encoder 16 for image processing ... Connected pouch discharge nozzle 17 ... Tool / Liquid leak detection sensor C ... Conveying direction X ... First direction Y ... Second direction 80 ... CPU 81 ... RAM 82 ... ROM 83 ... Counter 84 ... Timer 85 ... Storage device 86 ... I / O interface 87 ... Bus

Claims (2)

A transport unit for transporting the light-shielding heat-sealed packaging material filled with the filling,
A first illuminating unit that is arranged on one side of the conveying unit and that illuminates the heat-sealed packaging material from a first direction that is set to cross the conveying unit obliquely from above;
A first imaging unit that images the seal part when the seal part of the heat-sealed packaging material being conveyed passes through the first illumination unit;
2nd illumination which is arrange | positioned in the conveyance direction of the said 1st illumination part, and illuminates the said heat-sealing packaging material from the 2nd direction set in the direction of line symmetry with respect to the said 1st direction and a perpendicular line. And
A second imaging unit that images the seal part when the seal part of the heat-sealed packaging material being conveyed passes through the second illumination part;
A seal failure detection unit that processes an image captured by the imaging unit and detects a seal failure in the image;
A discharge part for discharging the relevant heat-sealing packaging material as a defective product;
An apparatus for detecting a sealing failure of a light-shielding heat-sealing packaging material, comprising: While the light-shielding heat-sealing packaging material filled with the filler and sealed by heat fusion is being conveyed, the heat-sealing packaging material is illuminated from a first direction set across the conveying portion from above obliquely while the light-shielding heat-sealing packaging material is illuminated. A first imaging step of imaging the seal portion of the heat seal packaging material;
After being imaged in the first imaging step and transported downstream from the imaging position, the heat seal wrapping material is irradiated with the heat from a second direction set in line symmetry with respect to the first direction and a vertical line. A second imaging step for imaging the seal portion of the seal packaging material;
Processing steps for processing the images imaged in the first imaging step and the second imaging step;
A determination step of detecting a seal failure with reference to the processed image;
A discharge step for discharging the applicable heat-sealing packaging material as a defective product;
A sealing failure detection method for a light-shielding heat-sealing packaging material, comprising: