JP2009162685A - Apparatus for inspecting packaged food with near-infrared light - Google Patents

Abstract

To provide an inspection apparatus capable of inspecting all products with high accuracy and low cost for the presence or absence of foreign substances contained in food in a packaging material in an inspection process before shipment of packaged food. Conveying means composed of a member that transmits near infrared rays, or conveying means for placing and conveying packaged food on a conveyor connecting portion or conveyor having an opening corresponding to an imaging area of the packaged food, and a line that emits near infrared rays The near-infrared irradiation means for irradiating the packaged food with near-infrared light from the shaped light source, and the line sensor disposed opposite to the line-shaped light source across the conveyor conveyance surface, and near the packaged food illuminated by the line sensor Based on the image signal of the near-infrared transmission image output from the imaging means, the imaging means for imaging the infrared transmission image, and the presence or absence of foreign matter attached to the front and back surfaces of each thin plate food in the packaging material Comprising an inspection means for inspecting the presence or absence of foreign matter contained in the interior of the thin plate food simultaneously, the.
[Selection] Figure 1

Description

  The present invention relates to an apparatus for inspecting the presence or absence of foreign substances contained in a thin plate-like food in a packaging material in an inspection process before shipment, with a packaged food in which at least one thin plate-like food is packaged being inspected, Packaged foods that can be inspected for the presence or absence of foreign matter regardless of the front or back side or the number of many sheets, even for packaged foods that are packaged in a state where multiple sheets of food are stacked on top of each other The present invention relates to a foreign substance inspection apparatus.

In the last few years, food safety has been increasingly demanded, and as always, foreign object detection has become a major theme without a universal method. For detecting foreign matter on thin workpieces such as rice crackers and seaweed, metal detectors and image processing based on visible light are used, but non-metal such as paint adheres to the back of the workpiece and the second and subsequent layers. Alternatively, it was difficult to detect when it was mixed inside the workpiece. In addition, detection by image processing using X-rays can detect foreign matter in the case of relatively thick workpieces, but because the wavelength is too short and the transmission power is too strong, thin workpieces such as rice crackers and laver In the case of, the current situation is no use. In addition, there are many foods that wrap food in packaging materials such as synthetic resin films and Japanese paper for hygiene considerations, but it is difficult to detect foreign objects because of the fact that visible light is not reflected and the visible light does not pass through the packaging material. (Refer to Non-Patent Documents 1 and 2, for example, regarding packaged food inspection systems)
Kazuya Kanda, Kazuo Ito, Tokuji Okada, “Method for detecting foreign substances in food dough based on light transmission”, Transactions of the Society of Instrument and Control Engineers, October 2001, Vol. 37, No. 10, p916-925 Kanda Kazuya, Okada Tokuji, Ito Kazuo, “Packaged Food Quality Judgment System Using Transmitted Light Amount”, Proceedings of the Society of Instrument and Control Engineers, October 2001, Vol. 37, No. 10, p926-933

  The present invention has been made for the above-mentioned circumstances, and an object of the present invention is to accurately and inexpensively determine the presence or absence of foreign substances contained in food in a packaging material in an inspection process before shipment of packaged food. An object of the present invention is to provide an inspection apparatus capable of inspecting all products with a simple configuration. Specifically, in the inspection process before shipment of packaged food that is continuously transported on a conveyor, when the object is to be inspected that is packaged in a state where a plurality of thin plate foods such as plate seaweed and rice crackers are stacked It is another object of the present invention to provide an inspection apparatus capable of inspecting all articles in real time for the presence or absence of foreign matter regardless of the front and back sides and the number of sheets.

  The present invention includes a packaged food in which at least one sheet-shaped food is packaged by a packaging material such as Japanese paper or synthetic resin film, and is included in each sheet-shaped food in the packaging material in an inspection process before shipment. The object of the present invention is to provide a conveyor formed of a member that transmits near infrared rays, or an opening corresponding to the imaging area of the packaged food in a conveyor connecting portion or a conveyance surface. A conveyor means for placing and transporting the packaged food on a conveyor, and a line-shaped light source in which a large number of small light sources emitting near infrared rays are arranged in a substantially straight line, and below or above the conveyor and on the packaged food. Near-infrared illumination that irradiates the near-infrared rays to the packaged food conveyed by the conveying means from the line-shaped light source arranged in a direction orthogonal to the conveying direction. And a line sensor disposed opposite to and parallel to the line of the line-shaped light source across the conveying surface of the conveyor, and the line sensor receives near infrared rays from the line-shaped light source that has passed through the packaged food. And an image pickup means for picking up a near-infrared transmission image of the packaged food, and an image signal of the near-infrared transmission image output from the image pickup means, attached to the front and back surfaces of each thin plate food in the packaging material This is achieved by providing inspection means for simultaneously inspecting the presence or absence of foreign matter and the presence or absence of foreign matter contained in each thin plate food.

Furthermore, the above object of the present invention is to
The near-infrared ray is a near-infrared ray including a part of a specific wavelength region in a wavelength region of 780 nm to 1100 nm,
The lamellar food is a lamellar solid food containing rice crackers and laver,
The inspection object is a packaged food that is sealed by the packaging material in a state in which a plurality of the thin plate foods are stacked,
The inspection means inspects the presence or absence of the foreign matter and inspects the shape defect of the thin plate food based on the image signal of the near infrared transmission image output from the imaging means,
Is achieved more effectively by each.

Furthermore, the above object of the present invention is to
The line-shaped light source is configured by arranging the LEDs emitting the near infrared rays without any gaps;
The illumination unit circuit as the near-infrared irradiation means includes an LED parallel circuit in which LEDs emitting near-infrared rays are connected in parallel, a switching element that controls on / off of the lighting operation of the LED, and the LED parallel circuit via the switching element A smoothing circuit and a constant current circuit connected in series to
A diffusion plate is provided above the light emitting surface of the line light source;
The inspection means binarizes a multi-gradation density level obtained by sampling the near-infrared transmission image in pixel units with a foreign substance determination threshold value, and a count value of pixels exceeding the threshold value exceeds a predetermined allowable range. Determining that there is a foreign substance on either the front surface, the back surface, or the food interior of each thin plate food in the packaging material,
Is achieved more effectively by each.

  According to the present invention, the near-infrared rays that pass through the packaged food are used as illumination light, and the foreign matter is detected based on the near-infrared transmission image that has passed through the packaged food. Even in the case where an object to be inspected is packaged in a state where a plurality of sheets are overlapped, it is possible to inspect for the presence or absence of foreign matter regardless of the front, back, inside, and the number of many sheets. In addition, because the packaged food to be transported is inspected using a line light source and line sensor, the presence or absence of foreign substances contained in the food in the packaging material can be checked with high accuracy in the inspection process before shipment of the packaged food. In addition, all products can be inspected with an inexpensive configuration. Furthermore, it is possible to provide an apparatus having an inspection function for foreign matter and defective shape at low cost by adopting a form for inspecting both the presence and absence of foreign matter and defective shape based on the information of the near infrared transmission image from the imaging means. It becomes possible.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic configuration diagram showing an example of the overall configuration of a foreign object inspection apparatus for packaged food according to the present invention (hereinafter referred to as “food inspection apparatus”). The food inspection apparatus shown in FIG. 1 uses a thin plate-like solid food such as rice cracker or laver (hereinafter referred to as “thin plate food”) as an inspection target, and foreign substances adhering to the front and back surfaces of the food and inside the food. It is a device that optically inspects the presence or absence of contained foreign substances, especially in the packaging material of packaged food that is transported on a conveyor for thin plate foods that have been packed with packaging material such as Japanese paper or synthetic resin film. It is suitably applied as an apparatus for inspecting all products for the presence or absence of foreign substances contained in each food.

  In this embodiment, a near infrared light source 10 is arranged on one side and a line sensor 20 such as a line scan camera is arranged on the other side of the conveying surface of the conveyor 30 operating continuously, and the packaged food 1 to be inspected is arranged. After obtaining the timing of imaging with the trigger signal from the sensors (2a, 2b) to be detected, a continuous transmission image by near infrared rays is acquired, and the image processing unit 40 performs inspections such as foreign matter inspection and chipping. In addition, without providing the sensors (2a, 2b), a continuous image captured continuously by the line sensor 20 is acquired, and the threshold value of the image itself (threshold value for determining the presence or absence of packaged food) is used as a trigger signal. Thus, it is also possible to perform a foreign object inspection, a defect inspection, or the like on an image obtained by adding several frames before and after.

  Hereinafter, a case where a multi-layered plate nori (hereinafter simply referred to as “nori”) encapsulated with a packaging material is used as an inspection object will be described in detail.

  In FIG. 1, the food inspection apparatus is a diagram in which an illumination unit 10 that illuminates a packaged food 1 to be inspected, an imaging unit 20 that captures a transmission image of the packaged food 1, and the packaged food 1 are placed on a conveyor. 1 includes a transport unit 30 for transporting in the direction of arrow X in FIG. 1 and an image processing unit 40 for processing the transmission image of the packaged food 1 to inspect for the presence or absence of foreign matter.

  The illumination part 10 is comprised from the illumination unit which irradiates the near-infrared luminous flux L with respect to the packaged food 1, As the light source, the linear light source of the structure which has arrange | positioned many small light sources which emit near-infrared substantially linearly is used. Used. As the light emitting element of the line light source constituting the illumination unit (hereinafter referred to as “near infrared irradiation unit”) 10, a near infrared light emitting diode (hereinafter referred to as “near red”) having a peak wavelength in the near infrared region that transmits the packaged food 1. It is preferred to use an "outside LED".

  The imaging unit 20 includes a line sensor such as a color line scan camera. In this embodiment, a color CCD (Charge Coupled Device) linear sensor is used as a line sensor for capturing a near-infrared transmission image of the packaged food 1. Used. A CMOS (Complementary Metal Oxide Semiconductor) linear sensor capable of receiving near-infrared light may be used. The reason why the line sensor is used for the image pickup unit (hereinafter simply referred to as “camera”) 20 is that the line sensor has a higher resolution than the area sensor, and when inspecting the packaged food 1 to be conveyed, This is because an image signal is output for each scan, so that continuous image processing can be easily performed.

  The conveyance unit 30 includes conveyance means (hereinafter referred to as “conveyance conveyor”) including a conveyor (round belt in this example), a pulley, a drive motor, and the like, and a member of the conveyance conveyor 30 transmits near infrared rays. A translucent member is used. In addition, as a structure of the conveyance part 30, although it is preferable to set it as the structure using the conveyor which consists of a member which permeate | transmits a near infrared ray like this example, the opening corresponding to the imaging area | region of the packaged food 1 is made into a conveyor connection part. It is good also as a structure which uses the conveyor provided between the conveyor surface (between a conveyor and a conveyor).

  The image processing unit 40 is configured by a computer such as a PC on which an image processing board 41, image processing software 42, an input / output board, and the like are mounted. In addition to the near-infrared irradiation unit 10 and the camera 20, the input / output board 41 of the image processing unit 40 includes a light emitting / receiving sensor (hereinafter referred to as “food detection sensor”) for detecting the arrival of the packaged food 1 to the foreign substance inspection stage. 2a and 2b are connected via a PLC (Programmable Logic Controller) 3.

  As shown in FIG. 1, the food detection sensors 2a and 2b are attached to the upper and lower ends of one end of the conveyor 30, and the image processing unit 40 operates the camera 20 in response to the output signal of the light receiving sensor 2b. Sampling of the image data of the infrared transmission image is started, and a foreign matter inspection process and an appearance quality inspection process to be described later are executed based on the image data.

  Next, the arrangement configuration of the near infrared irradiation unit 10 and the camera 20 will be described.

  FIG. 2 is a plan view showing an example of the configuration of the conveyance unit 30 and the arrangement of the near infrared irradiation unit 10 of the food inspection apparatus shown in FIG. FIG. 3 is a rear view of the transport unit 30 of FIG. 2 as viewed from the direction of the arrow X, and shows the arrangement of the near infrared irradiation unit 10 and the camera 20.

  In the example of the conveyance unit 30 shown in FIG. 2, N transparent round belts 31 having a radius Rmm are arranged at intervals of Wmm in the width direction of the conveyance path so that laver having a length of 190 mm and a width of 100 mm can be mounted. (For example, W = 50, N = 3, R = 2.5). The members 32 provided on both sides of the transport unit 30 are guide members, and the laver packaging 1 placed on the transparent round belt 31 is transported in the arrow X direction at a predetermined speed. In addition, it is good also as a structure which feeds back and controls a speed to an image receiving side with an encoder or a servo so that the conveyance speed of the package 1 may become a target speed. In this example, the conveying speed of the conveying unit 30 is 10 to 100 m / min so that it can be driven in conjunction with the speed of the conveying system of the production line (for example, the conveying conveyor connected to the upstream end of the conveying conveyor). It is variable within the range.

  In the present embodiment, as shown in FIG. 2, the near-infrared irradiation unit 10 is disposed below the conveyor (transparent round belt 31) and in a direction orthogonal to the conveyance direction X of the packaged food 1, and the near-infrared irradiation unit 10 The linear light source 11 of the irradiation unit 10 is configured to irradiate a linear near-infrared light flux over the entire width direction of the packaged food 1. The line light source 11 may be configured to irradiate the packaged food 1 with near-infrared light fluxes L that are substantially parallel to each other, as shown in FIG. A diffusing plate 11B (for example, a diffusing plate made of milky white resin material) is provided above the light emitting surface, and the packaged food 1 is irradiated with near-infrared diffused light through the diffusing plate 11B.

  As shown in FIG. 3, the line sensor 21 constituting the camera 20 is disposed in parallel with the line of the linear light source 11 of the near-infrared irradiation unit 10 with the conveyer (transparent round belt 31) interposed therebetween, and the packaged food 1 The near-infrared light L from the line-shaped light source 11 that has passed through is received by the line sensor 21 and a near-infrared transmitted image of the packaged food 1 is captured. In the present embodiment, the line light source 11 is arranged below the conveyor, and the line sensor 21 is arranged above the conveyor (in this example, about 300 to 600 mm above the conveyor surface). It is also possible to arrange the line sensor 21 at the top and arrange the line light source 11 above the conveyor. In addition, the conveyance part 30 is designed so that three sets of illumination and a camera can be installed. In order to be able to inspect various products, a configuration in which a line light source 11 that emits different wavelengths in the near infrared region and a line sensor 21 that can receive the wavelengths may be further added. Further, the inspection of the shape defect (the appearance quality including a chip) may be performed by using a surface light source using a red LED and a two-dimensional CMOS camera.

  As shown in FIG. 3, the packaged food 1 to be inspected in this example is a rectangular laver 1b laminated on a multilayer sheet, which is packaged with a packaging material 1a. However, the packaging material 1a made of Japanese paper or a resin film is used. Since the transmittance of near infrared rays is high, it does not affect the inspection of foreign matters and inspection of shape defects (appearance quality such as chips and holes). However, when the packaged food 1 having a film pattern with a low near-infrared transmittance is used as an inspection target, it is difficult to distinguish the foreign object from a foreign substance, and therefore, the image portion of the film pattern is removed by pattern matching processing.

  Next, the near-infrared wavelength region used for foreign object inspection will be described.

  As a result of examining the transmission spectrum of laver in a wavelength range of 400 to 2500 nm using an ultraviolet-visible spectrophotometer, the graph of FIG. 4 (the horizontal axis represents wavelength (nm) and the vertical axis represents transmittance T (%)). As shown in Fig. 4, it was found that the transmittance of laver increases rapidly in the wavelength region exceeding 800 nm (about 780 nm). Further, the absorption spectrum of seaweed was examined in the same manner. As a result, as shown in the graph of FIG. 5 (a graph in which the horizontal axis represents wavelength (nm) and the vertical axis represents absorbance (Abs)), the absorbance is about 620 nm. It turned out to be higher in the area. The examples in Fig. 4 and Fig. 5 are the results of examining three pieces of laver from Hyogo, Fukuoka, and Sanriku (a total of 9 pieces) in order to confirm the difference by production area, grade, and lot. Was also found to have approximately the same optical properties. In addition, the components of laver are mainly proteins, carbohydrates, and lipids.

  The food inspection apparatus according to the present invention targets rice crackers in addition to seaweed, but many foods mainly composed of carbohydrates and lipid proteins transmit very well in the wavelength range of 780 nm to 1100 nm.

  Therefore, in the present invention, the packaged food 1 to be inspected is irradiated using near-infrared rays including a specific wavelength range in a part of the wavelength range of 780 nm to 1100 nm. As the near-infrared irradiation means, a halogen lamp and an optical filter can be used. In this embodiment, a near-infrared LED having advantages such as long life, low cost, and easy availability is used.

  Next, the configuration of the near infrared irradiation unit 10 will be described.

  FIG. 6 is a plan view illustrating a configuration example of a light emitting unit of the near infrared irradiation unit 10. In this example, the width of the conveyance path serving as the imaging area is approximately 200 mm, and M (M = 40 in this example) near-infrared LEDs 11A are provided as shown in FIG. 6 so as to cover the imaging area. The unit configuration is arranged with a pitch of 5 mm and without gaps, and is further covered with a polished milky white acrylic plate (diffusion plate 11B in FIG. 3) and has a diffusion line light source having a length of 300 mm and a width of 30 mm. In the present embodiment, each near-infrared LED 11A is an LED having a peak wavelength in the near-infrared region having a wavelength near 870 nm (in this example, manufactured by Hamamatsu Photonics) as shown in the spectral characteristic diagram of FIG. L1939). In addition, the light source used for the near-infrared irradiation unit 10 is preferably a near-infrared light source having a peak wavelength within a wavelength range of about 780 nm to 1100 nm, and is not limited to 870 nm.

  FIG. 8 is a circuit diagram illustrating a configuration example of an illumination unit (near infrared irradiation unit). The illumination unit circuit in this example includes an LED parallel circuit in which an LED group in which one or more near-infrared LEDs 11A are connected in series is connected in parallel, a switching element 11a that controls on / off of the lighting operation of the near-infrared LED 11A, and the switching element A smoothing circuit 11b and a constant current circuit 11c connected in series to the LED parallel circuit via 11a. In this example, the constant current circuit 11c uses a variable output type shunt regulator (for example, TL431) and a resistor, the smoothing circuit 11b uses a capacitor, and the switching element 11a uses a silicon N-channel MOS field effect transistor. Yes. Further, a variable resistor 11d and an amplifier 11e are connected between the constant current circuit 11c and the smoothing circuit 11b, and the near-infrared LED 11A is driven with a drive voltage of 16V. In the present embodiment, the near infrared irradiation unit having such a circuit configuration is driven and controlled by a computer of the image processing unit.

  With the configuration as described above, an operation example of the food inspection apparatus according to the present invention and the inspection process of foreign matter and appearance quality will be described with reference to FIG.

  The packaged food 1 to be inspected is conveyed in the direction of arrow X in FIG. 1 while being placed on the conveyor 30. When the detection signal of the packaged food 1 is transmitted from the food detection sensors 2a and 2b to the input / output board 41 of the image processing unit 40, the image processing unit 40 operates the camera 20 using the detection signal as a trigger to Sampling of image data of the transmitted near-infrared transmission image is started. The inspection means (image processing software 42 in this example) of the image processing unit 40 compares the multi-gradation density level obtained by sampling the near-infrared transmission image in units of pixels with a foreign substance determination threshold (binarization reference value). To binarize. The binarization reference value is set by, for example, the mode method. The mode method is one of general reference value setting methods in which a luminance histogram of an image is examined and a valley between modes of the distribution is used as a threshold value. The foreign substance determination threshold varies depending on the thickness of the product, light transmittance (degree of scattering absorption in transmission of near-infrared light), etc., and is thus set for each type of inspection object and stored in the storage means.

  Here, an example of an actual image in the case where foreign matter is mixed will be described by taking a plate seaweed packaged with a packaging material as an example.

  The image example of the packaged food 1 shown in FIG. 9 is an image example of a plate seaweed packaged with a plastic film used for “rice balls” used in a convenience store, etc. FIG. 9A shows visible light. FIG. 9B shows an image on the front surface side, which is taken by the above method. As shown in FIG. 9A, the film for rice balls is provided with a film pattern 1a such as an opening order or an explanatory diagram. In this example, as shown in a broken-line circle frame in FIG. 9B, a case where a foreign substance 1b (a 2 mm square gum tape piece in this example) is attached to the back surface of the plate seaweed 1 is taken as an example. In this case, it can be seen that it is difficult to detect the foreign matter 1b by visual inspection from the surface side or inspection of the image from the surface side by visible light.

  A near-infrared transmission image obtained by irradiating the packaged food 1 with near-infrared rays on the packaged food 1 from the surface side of the packaged food 1 by the near-infrared irradiation unit 10 in FIG. The image is as shown in (A). As shown in the image example of FIG. 10 (A), near-infrared light is transmitted through seaweed, and even when the foreign matter 1b adheres to the back side, the portion of the foreign matter 1b should appear black compared to others. Recognize. An image obtained by binarizing the near-infrared transmission image is the image of FIG.

  As shown in the image example of FIG. 10B, it can be seen that after the binarization processing, the foreign matter 1b and the film pattern 1a are extracted in black. In the case of laver, paint pieces are the main foreign matter, but these foreign matters are also extracted black after binarization because they have low near-infrared transmittance. In addition, when the film pattern 1a does not exist or the film pattern 1a exists and has a high near-infrared transmittance, the foreign object 1b can be detected from the binarized image. it can.

  In this example, since the film pattern 1a having a low near-infrared transmittance exists, the inspection unit of the image processing unit 40 removes the film pattern 1a from the binarized image by image processing such as pattern matching, and the foreign matter 1b. Extract only. And, for example, when the count value of the number of extracted pixels exceeds a predetermined allowable range (for example, a preset reference pixel number), either on the front surface, the back surface of each seaweed in the packaging material, or inside the food It is determined that there is a foreign object. Subsequently, the inspection unit of the image processing unit 40 regards the packaged food 1 that has been determined as having a foreign object as a defective product, and transmits a signal indicating that to, for example, an external computer. For example, in the case of a configuration in which an exclusion device for rejecting defective products is provided on the conveyor 30 or a downstream conveyor connected to the conveyor 30, the inspection means of the food inspection device sends an exclusion signal to the exclusion device. The packaged food 1 is automatically excluded from the production line as a defective product. And the process mentioned above is repeated without stopping a production line.

  By the above processing, it is possible to simultaneously inspect for the presence or absence of foreign matter adhering to the front and back surfaces of each thin plate food in the packaging material and the presence or absence of foreign matters contained in each thin plate food.

  In the example of FIG. 9, the case where the foreign matter 1b is attached to the first sheet on the back side of the plate seaweed is taken as an example. Regardless of metal (paint pieces, sand, etc.), foreign substances outside the components of laver can be detected with high accuracy. That is, according to the food inspection apparatus according to the present invention, foreign matter in seaweed or small foreign matter of about 1 mm, which has been difficult in the past, is high regardless of the inside and outside of the front and back sides, the plate laver, and the number of sheets. It becomes possible to detect with accuracy.

  Next, the inspection for defective shape will be described. The shape defect inspection process is executed concurrently with the foreign object inspection process. The term “defective shape” as used herein refers to a case where a thin plate food (in this example, laver) in the packaging material has a chip or a hole.

  When inspecting the shape defect, the inspection means of the image processing unit 40 obtains a near-infrared transmission image by taking the operation timing based on the detection signal of the packaged food 1 from the food detection sensors 2a and 2b, similarly to the foreign object inspection. To do. Then, the multi-tone density level sampled in units of pixels is compared with a shape defect determination threshold value (threshold value for determining the seaweed portion of the infrared transmission image) and binarized, and the number of pixels in the black portion is counted. . Then, the count value (total value) is compared with a preset normal number of normal seaweed pixels, and if the total value of the black portion is less than the normal number of normal seaweed pixels, it is determined that there is a defect. The packaged food 1 determined to have a chip is regarded as a defective product, and a signal indicating that is transmitted to, for example, an external computer. Then, in the same manner as when foreign matter is detected, an exclusion signal is transmitted to the exclusion device, and the packaged food 1 is automatically excluded from the production line as a defective product, and the above-described processing is repeated.

  FIG. 11A shows an example of an image of a normal product of one plate seaweed by visible light, and FIG. 11B shows an example of an image of a defective product (shape defect product having a chip 1c). 12A shows an image example after binarization processing of an infrared transmission image in a normal product, and FIG. 12B shows an image example after binarization processing of an infrared transmission image in a defective product. Thus, it can be seen that the number of pixels in the black portion is clearly smaller in the state where the chip 1c is present as compared with the normal state.

  The conventional inspection apparatus has low detection accuracy for detecting the presence or absence of chipping (for example, limited to four corners with a size of about 2 cm on a side), and is a large and expensive apparatus, but the food inspection according to the present invention According to the apparatus, since near infrared rays having a wavelength range of about 780 to 1100 nm are used, it is possible to discriminate defective products with high accuracy using relatively inexpensive line CCD sensors and near infrared LEDs. . For example, when the wavelength region exceeds 1100 nm, it is necessary to use an InGaAs line sensor, and the price is several times higher than that of a line CCD sensor.

  In the above-described embodiment, when inspecting a defective shape such as a chip or a hole, the pixel value is binarized using one threshold value, and the count value of the black portion is compared with the number of pixels of normal seaweed. In the above description, the method for determining the shape defect is described as an example. However, in consideration of the case where products such as plate seaweed and rice crackers are superimposed, a method for inspecting individual products may be used. For example, when the product is superimposed, the density of the acquired image changes from that of the 1 sheet part, the 2 sheet overlapping part,. If the area value of n overlapping portions and the number of shade pixels are integrated and the integration is compared with the good product standard for the entire product, defective products including the overlapping portions can be inspected.

  Next, another embodiment relating to inspection of shape defects such as chipping will be described.

  As a result of the experiment using the above-mentioned spectrophotometer, laver has a sharp increase in transmittance in the wavelength region exceeding 800 nm as shown in FIG. 4, and the absorption rate (absorbance: Abs) is shown in FIG. As can be seen from the graph, it becomes higher in the region of about 620 nm. Therefore, in the shape defect inspection for foods having the same components as seaweed, if a light source having a wavelength of about 620 nm is used, detection can be performed with higher accuracy. However, in the case of processed foods such as rice crackers, the shape defect is a problem in appearance quality and does not impair health. Therefore, the inspection in the above-described embodiment is considered sufficient.

  The food inspection apparatus described below is applied as an apparatus for detecting a shape defect such as a fine chip or a hole with high accuracy.

  FIG. 13 is a schematic configuration diagram illustrating a configuration example of another food inspection apparatus according to the present invention corresponding to FIG. 1, and the same components are denoted by the same reference numerals and description thereof is omitted. In addition, since the foreign substance inspection process and the shape defect inspection process are the same as those in the above-described food inspection apparatus, description thereof will be omitted, and here, differences in the apparatus configuration will be described.

  Compared with the food inspection apparatus of FIG. 1, the food inspection apparatus shown in FIG. 13 includes a surface light source 12 as an illumination means for shape defect inspection and an area sensor 22 as an imaging means for shape defect inspection. The configuration is as follows. As a light source that emits light having a wavelength of around 620 nm, a red LED is preferably used. In addition, as an illumination unit which has the surface light source 12, you may use the illumination unit which uses an organic EL (Electro Luminescence) element as a light source. In the present embodiment, the surface light source 12 of the lighting unit used for the shape defect inspection has a configuration in which red LEDs are arranged without a gap in a two-dimensional area corresponding to the inspection region (the entire packaged food). On the other hand, an inexpensive CMOS camera can be used as the area sensor 22. By adopting such a configuration, it becomes possible to detect a shape defect with higher accuracy.

  In the above-described embodiment, specific numerical values such as the width of the conveyance path and the number of near-infrared LEDs are shown and described, but the present invention is not limited to these numerical values. Further, the case where the near-infrared light source is a line light source has been described as an example, but a near-infrared LED may be a surface light source configured in a two-dimensional area. Moreover, although the case where the transparent round belt is used as the conveying means has been described as an example, a flat transparent belt may be used, or a configuration using a conveying roller made of a member that transmits near infrared rays may be used. Moreover, although the form in which the inspection process is executed by the image processing software has been described as an example, a part or all of the processes may be executed by hardware.

It is a schematic structure figure showing an example of the whole food inspection device composition concerning the present invention. It is a top view which shows an example of the structure of the conveyance part of the food inspection apparatus which concerns on this invention, and the arrangement configuration of a near-infrared irradiation unit. It is a schematic diagram which shows the arrangement configuration of the near-infrared irradiation unit and camera of the food inspection apparatus according to the present invention. It is a graph which shows the transmission spectrum of nori. It is a graph which shows the absorption spectrum of a laver. It is a schematic diagram which shows the structural example of the near-infrared irradiation unit which concerns on this invention. It is a graph which shows the spectral characteristic of near infrared LED used for this invention. It is a circuit diagram which shows the structural example of the near-infrared irradiation unit which concerns on this invention. It is a figure which shows an example of the captured image by visible light illumination of the packaged food in which the foreign material was mixed. It is a figure which shows an example of the captured image by the near-infrared illumination of the packaged food in which the foreign material was mixed. It is a figure which shows an example of the captured image by the visible light illumination of a normal product and a shape defect product. It is a figure which shows an example of the picked-up image by near-infrared illumination of a normal product and a shape defect product. It is a schematic block diagram which shows the other structural example of the food inspection apparatus which concerns on this invention.

Explanation of symbols

1 Packaged food 1a Film pattern 1b Foreign matter 1c Chip 2a, 2b Food detection sensor (light emitting / receiving sensor)
3 PLC
10 Illumination unit (near infrared irradiation unit)
11 Line light source 11A Near-infrared LED
11B Diffuser 11a Switching element 11b Smoothing circuit 11c Constant current circuit 11d Variable resistor 11e Amplifier 12 Surface light source 20 Imaging unit (camera)
21 Line sensor 22 Area sensor 30 Conveying section 31 Transparent round belt 32 Guide member 40 Image processing section 41 Image processing board 42 Image processing software 43 Input / output board

The present invention, as the inspection target packaging food plurality superimposed thin plate food groups are packaged by packaging materials, said the presence of foreign particles contained in the inspection process before shipment to the thin plate food in the packaging material The present invention relates to an apparatus for inspecting a total area value of a thin plate-like food group in a packaging material, and the above object of the present invention is to provide a plurality of pieces arranged in parallel with the conveying direction and at a predetermined interval in the conveying path width direction conveying means and the light source that Hassu the near infrared having a linear light source comprising base parallel to the straight linear, below or above the conveyor for conveying and placing of the packaged food to a conveyor comprising a transparent belt And near-infrared ray irradiation means for irradiating the near-infrared ray to the packaged food conveyed by the conveyance means from the line light source arranged in a direction orthogonal to the conveyance direction of the packaged food, and the conveyor The transport surface of A near-infrared transmission image of the packaged food by receiving near-infrared light from the line-shaped light source transmitted through the packaged food by the line sensor. Based on the image signal of the near-infrared transmission image output from the imaging means, the presence / absence of foreign matter adhering to the front and back surfaces of each thin plate food in the packaging material, and each thin plate food A first inspection process for simultaneously inspecting the presence or absence of foreign matter contained therein is performed, and at the same time as the first inspection process, based on the image signal of the near-infrared transmission image, By integrating the area values obtained by processing the gray image of the thin plate-like food group, and considering the integrated value as the total area value of the plurality of thin plate-like food groups superimposed, ,in front And checking means for performing a second test process of testing the good / bad of the whole thin plate-like food groups in packaging material is achieved by providing a.

Furthermore, the above object of the present invention is to
The near-infrared ray is a near-infrared ray including a part of a specific wavelength region in a wavelength region of 780 nm to 1100 nm,
The thin plate food, rice cracker, it is lamellar solid food product comprising a plate seaweed, thus be more effectively achieved respectively.

Furthermore, the object of the present invention is that the line-shaped light source is formed by arranging the LEDs emitting the near infrared rays without gaps,
An exclusion device that excludes the packaged food according to an exclusion signal output from the inspection unit is provided in the conveyor or a downstream conveyor connected to the conveyor, and the inspection unit includes the packaged food as a defective product. When the determination is made, the rejection signal is transmitted to the rejection device to automatically exclude the packaged food determined to be defective from the production line, and the near-infrared transmission image signal By inspecting all the packaged foods that are continuously conveyed on the conveyor by repeating the inspection process based on
Is achieved more effectively by each.

FIG. 1 is a schematic configuration diagram showing an example of the overall configuration of a packaged food quality inspection apparatus (hereinafter referred to as “food inspection apparatus”) according to the present invention. The food inspection apparatus shown in FIG. 1 uses a thin plate-like solid food such as rice cracker or laver (hereinafter referred to as “thin plate food”) as an inspection target, and foreign substances adhering to the front and back surfaces of the food and inside the food. It is a device that optically inspects the presence or absence of contained foreign substances, especially in the packaging material of packaged food that is transported on a conveyor for thin plate foods that have been packed with packaging material such as Japanese paper or synthetic resin film. It is suitably applied as an apparatus for inspecting all products for the presence or absence of foreign substances contained in each food.

The present invention is directed to a packaged food in which a plurality of laminated sheet food products are packaged with a packaging material, and the presence or absence of foreign matters contained in each sheet food in the packaging material in the inspection process before shipment The present invention relates to an apparatus for inspecting a shape defect of a thin plate-like food group in a packaging material, and the object of the present invention is to provide a plurality of pieces arranged in parallel with the transport direction and at a predetermined interval in the transport path width direction. Conveying means for placing and transporting the packaged food on a conveyor made of a transparent belt, and a line-shaped light source in which light sources emitting near infrared rays are arranged in a straight line, and below or above the conveyor and of the packaged food Near-infrared irradiation means for irradiating the near-infrared light to the packaged food conveyed by the conveyance means from the line-shaped light source arranged in a direction orthogonal to the conveyance direction, and a conveyance surface of the conveyor A near-infrared transmission image of the packaged food by receiving near-infrared light from the line-shaped light source transmitted through the packaged food by the line sensor. Based on the image signal of the near-infrared transmission image output from the imaging means, the presence / absence of foreign matter adhering to the front and back surfaces of each thin plate food in the packaging material, and each thin plate food A first inspection process for simultaneously inspecting the presence or absence of foreign matter contained therein is performed, and at the same time as the first inspection process, based on the image signal of the near-infrared transmission image, The area value obtained by processing the gray-scale images of the thin plate food group is integrated, and the total is compared with the non-defective product standard to inspect the good / bad of the entire thin plate food group in the packaging material. 2 inspection And checking means for executing the process is achieved by providing a.

Furthermore, the above object of the present invention is to
The near-infrared ray is a near-infrared ray including a part of a specific wavelength region in a wavelength region of 780 nm to 1100 nm,
The thin plate-like food group is more effectively achieved by being a thin plate-like solid food containing rice crackers and plate nori.

FIG. 1 is a schematic configuration diagram showing an example of the overall configuration of a packaged food inspection apparatus (hereinafter referred to as “food inspection apparatus”) according to the present invention. The food inspection apparatus shown in FIG. 1 uses a thin plate-like solid food such as rice cracker or laver (hereinafter referred to as “thin plate food”) as an inspection target, and foreign substances adhering to the front and back surfaces of the food and inside the food. It is a device that optically inspects the presence or absence of contained foreign substances, especially in the packaging material of packaged food that is transported on a conveyor for thin plate foods that have been packed with packaging material such as Japanese paper or synthetic resin film. It is suitably applied as an apparatus for inspecting all products for the presence or absence of foreign substances contained in each food.

Claims (9)

Existence of foreign matter contained in each thin plate-like food in the packaging material in the inspection process prior to shipment, targeting at least one thin plate-like food packaged with a packaging material such as Japanese paper or synthetic resin film A device for inspecting
A conveyer configured to place and convey the packaged food on a conveyor formed of a member that transmits near-infrared rays or an opening corresponding to an imaging region of the packaged food on a conveyor connection unit or a conveyance surface;
A linear light source in which a large number of small light sources emitting near infrared rays are arranged in a substantially straight line, and the linear light source disposed below or above the conveyor and in a direction perpendicular to the direction of conveyance of the packaged food , Near-infrared irradiation means for irradiating the near-infrared rays to the packaged food conveyed by the conveying means,
The line sensor has a line sensor arranged opposite to the line of the line light source across the conveying surface of the conveyor, and receives near infrared rays from the line light source that has passed through the packaged food by the line sensor. An imaging means for capturing a near infrared transmission image of the packaged food;
Based on the image signal of the near-infrared transmission image output from the imaging means, the presence or absence of foreign matters attached to the front and back surfaces of each thin plate food in the packaging material and the presence or absence of foreign matters contained in each thin plate food Inspection means for simultaneously inspecting
A foreign matter inspection apparatus for packaged foods using near infrared rays, comprising:   The foreign matter inspection apparatus for packaged foods using near infrared rays according to claim 1, wherein the near infrared rays are near infrared rays including a part of a specific wavelength region in a wavelength region of 780 nm to 1100 nm.   The apparatus for inspecting foreign matter in packaged food using near infrared rays according to claim 1 or 2, wherein the thin plate food is a thin plate solid food containing rice crackers and plate seaweed.   4. The inspection of foreign matter in packaged food using near infrared rays according to claim 1, wherein the inspection object is packaged food sealed with the packaging material in a state where a plurality of the thin plate foods are stacked. apparatus.   5. The inspection unit according to claim 1, wherein the inspection unit inspects for the presence of the foreign matter and inspects for a shape defect of the thin plate food based on an image signal of a near-infrared transmission image output from the imaging unit. A foreign matter inspection device for packaged foods using near infrared rays as described.   The packaged food foreign matter inspection apparatus using near infrared rays according to any one of claims 1 to 5, wherein the line light source is configured by arranging the LEDs emitting the near infrared rays without gaps.   The illumination unit circuit as the near-infrared irradiation means includes an LED parallel circuit in which LEDs emitting near infrared rays are connected in parallel, a switching element that controls on / off of the lighting operation of the LED, and the LED parallel circuit via the switching element A device for inspecting foreign matter in packaged food using near infrared rays according to any one of claims 1 to 6, comprising a smoothing circuit and a constant current circuit connected in series to each other.   The apparatus for inspecting foreign matter in packaged food using near infrared rays according to any one of claims 1 to 7, wherein a diffuser plate is provided above the light emitting surface of the line light source.   The inspection means binarizes a multi-gradation density level obtained by sampling the near-infrared transmission image in pixel units with a foreign substance determination threshold value, and a count value of pixels exceeding the threshold value exceeds a predetermined allowable range. In this case, the foreign matter in the packaged food using near-infrared rays according to any one of claims 1 to 8, wherein the foreign material is determined to be present either on the front surface, the back surface, or the inside of the food in the thin plate food in the packaging material. Inspection device.