Image acquisition device, inspection device, and image acquisition method

Abstract

To acquire a high-quality temperature image without thermally affecting peripheral members.SOLUTION: An image acquisition device comprises: a light emitting unit that irradiates a seal part sealing a packaging medium including a substance absorbing light energy with at least light having a wavelength with which the substance absorbs the light; a light receiving unit that receives heat radiation from the seal part; and a two-dimensional image acquisition unit that acquires, from information received by the light receiving unit, temperature information on the seal part as a two-dimensional image. When the time at which the light emitting unit irradiates one side of the seal part with light is 0, and the time at which a surface temperature of the other side of the seal part reaches a peak is T, a quality determination unit sets the time t of at least one acquired two-dimensional image to be 0<t<T.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an image acquisition device, an inspection device, and an image acquisition method. [Background technology]

[0002] 2. Description of the Related Art Conventionally, there has been a package inspection device that inspects whether or not a sealed portion of a package formed by enclosing an article such as food in a packaging material and sealing it is properly sealed.

[0003] Patent document 1 discloses a device for inspecting defective seals on packages, which is configured to include an inspection means for detecting defective seals based on the temperature of the packages that has been raised by heating the packages using a heat-applying means. Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventional package inspection devices use a heat source to raise the temperature of the package, which makes handling the heat source complicated from a safety standpoint, and has the problem that the heat from the heat source can have a negative effect on surrounding components.

[0005] The present invention has been made in view of the above, and has an object to acquire a high-quality temperature image without thermally affecting surrounding components. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, the present invention provides a packaging material including a sealing part that seals a packaging material containing a substance that absorbs light energy, the packaging material including a light emitting part that irradiates light having at least a wavelength that is absorbed by the substance; a conveying unit that conveys the placed packaging material and a light emitting unit that are positioned on the opposite side of the conveying unit,A light-receiving unit that receives heat radiation from the seal portion, and a two-dimensional image acquisition unit that acquires temperature information of the seal portion as a two-dimensional image from the information received by the light-receiving unit, wherein an irradiation region where the light-emitting unit irradiates light on the seal portion and a light-receiving region where the light-receiving unit receives the heat radiation from the seal portion overlap at least partially when viewed from a direction perpendicular to the irradiation region or the light-receiving region, and the pass / fail determination unit sets the time when the light-emitting unit irradiates light on one side of the seal portion where at least a part of the irradiation region and the light-receiving region overlap to 0, and the time when the surface temperature on the other side of the seal portion where at least a part of the irradiation region and the light-receiving region overlap peaks to T, and the time t of at least one two-dimensional image to be acquired satisfies 0 < t < T.

Advantages of the Invention

[0007] According to the present invention, there is an effect that a high-quality temperature image can be acquired without giving a thermal influence to peripheral members.

Brief Description of the Drawings

[0008] [Figure 1] FIG. 1 is a schematic diagram showing a configuration example of an inspection apparatus according to a first embodiment. [Figure 2] FIG. 2 is a diagram showing an example of a package inspected by the inspection apparatus. [Figure 3] FIG. 3 is a diagram showing a configuration example of a packaging material. [Figure 4] FIG. 4 is a graph showing the absorption rate of aluminum. [Figure 5] FIG. 5 is a diagram showing an example of a point-type light-emitting source when irradiating a conveyed package. [Figure 6] FIG. 6 is a diagram showing an example of a point-type light-emitting source when irradiating a stopped package. [Figure 7] FIG. 7 is a diagram showing an example of a line-type light-emitting source when irradiating a conveyed package. [Figure 8] FIG. 8 is a diagram showing an example of a line-type light-emitting source when irradiating a stopped package. [Figure 9] FIG. 9 is a diagram showing an example of an area type light source when illuminating a package being conveyed. [Figure 10] FIG. 10 shows an example of an area light source when illuminating a stationary package. [Figure 11] FIG. 11 is a diagram showing an example of a point-type light-receiving element when receiving heat radiation from a package being conveyed. [Figure 12] FIG. 12 is a diagram showing an example of a point-type light-receiving element when receiving heat radiation from a stationary package. [Figure 13] FIG. 13 is a diagram showing an example of a line-type light-receiving element when receiving heat radiation from a package being conveyed. [Figure 14] FIG. 14 is a diagram showing an example of a line-type light-receiving element when receiving heat radiation from a stationary package. [Figure 15] FIG. 15 is a diagram showing an example of an area-type light-receiving element when receiving heat radiation from a package being conveyed. [Figure 16] FIG. 16 is a diagram showing an example of an area-type light-receiving element when receiving heat radiation from a stationary package. [Figure 17] FIG. 17 is a diagram showing a first layout example of a light-emitting section and a light-receiving section. [Figure 18] FIG. 18 is a diagram showing a second layout example of the light-emitting section and the light-receiving section. [Figure 19] FIG. 19 is a diagram showing a third layout example of the light-emitting section and the light-receiving section. [Figure 20] FIG. 20 is a block diagram showing the hardware configuration of the control device. [Figure 21] FIG. 21 is a functional block diagram showing the functions of the control device. [Figure 22] FIG. 22 is a graph showing an example of changes in surface temperature at positions in a good state and positions in a bad state. [Figure 23] FIG. 23 is a diagram showing a specific example of a two-dimensional image for determining whether a seal portion is good or bad. [Figure 24]FIG. 24 is a graph showing an example of the difference value of the surface temperature over time. [Figure 25] FIG. 25 is a diagram showing a specific example of a plurality of two-dimensional images for determining the quality of a seal portion by the quality determining unit according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of an image acquisition device, an inspection device, and an image acquisition method will be described in detail with reference to the accompanying drawings.

[0010] (First embodiment) 1 is a schematic diagram showing an example of the configuration of an inspection device 1 according to the first embodiment, and FIG. 2 is a diagram showing an example of a package 50 inspected by the inspection device 1. The inspection device 1 inspects whether the package 50 is properly sealed, and removes any defective package 50 from the production line.

[0011] First, the packaging body 50 will be described.

[0012] As shown in Fig. 2, packaging body 50 contains an item (for example, food such as curry or soup) inside bag-shaped packaging material 51. In packaging body 50 shown in Fig. 2, the bag-shaped opening is sealed by bonding packaging materials 51 together.

[0013] A single-layer plastic film, a surface-treated single-layer plastic film, or a plastic film made by laminating multiple layers of these is used for the packaging material 51 of the package 50. The surface treatment may include coating to impart moisture resistance, or vapor deposition of aluminum, silica, alumina, etc. to impart gas barrier properties.

[0014] Furthermore, a film obtained by laminating aluminum foil 51b (see FIG. 3) onto the above-mentioned film is used as packaging material 51 of package 50. Packaging material 51 laminated with aluminum foil 51b is used for applications requiring high gas barrier properties and moisture resistance. In particular, packaging material 51 laminated with aluminum foil 51b is a packaging container for retort food, and is what is known as a retort pouch.

[0015] Fig. 3 is a diagram showing an example of the configuration of a packaging material 51. The packaging material 51 shown in Fig. 3 is an example of the configuration of a packaging material 51 for a retort pouch. The packaging material 51 shown in Fig. 3 is formed by laminating a polyester (PET) film 51a, an aluminum foil 51b, and a non-oriented polypropylene (CPP) film 51c in this order from the surface. Films laminated with aluminum foil or aluminum-deposited film, such as the packaging material 51 shown in Fig. 3, have poor visual transparency, making it difficult to visually check the items contained inside the packaging material 51.

[0016] 2, the portion where the packaging materials 51 are bonded together and the bag-shaped opening is sealed is called the sealed portion 52. The sealed portion 52 is formed by heat sealing, which involves pressing a heated bar against the portion to be sealed to thermocompress it, or ultrasonic sealing, which involves melting and bonding the portion to be sealed using ultrasonic vibrations and pressure.

[0017] Here, we will briefly explain the manufacturing process of the package 50. The package 50 is manufactured by filling a bag-shaped packaging material 51 with an item (for example, food such as curry or soup) using a filling means (filling machine) not shown, and then sealing it with a seal part 52.

[0018] In this manufacturing process, the inspection device 1 performs a seal inspection on the package 50 sealed with the seal portion 52 to confirm that the seal is tight and that no leakage of the product will occur. The seal inspection determines whether the seal portion 52 is in a good or bad state. Poor states include, for example, pinched, pinhole, wrinkled, and perforated. Specifically, pinched is a defect in which an item is caught in the seal portion 52, pinhole is a defect in which a hole has opened in the seal portion 52, wrinkle is a defect in which the seal portion 52 has creases or overlapping wrinkles, and perforated is a defect in which a passage has opened in the seal portion 52 that allows the product to leak to the outside.

[0019] Next, the inspection device 1 will be described in detail.

[0020] As shown in FIG. 1, the inspection device 1 includes a transport unit 2, an image acquisition device 3, and a control device 4.

[0021] The image acquisition device 3 includes a light emitting unit 31 disposed below the transport unit 2 and a light receiving unit 32 disposed above the transport unit 2.

[0022] The conveying unit 2 includes a first conveying section 21 and a second conveying section 22. The first conveying section 21 and the second conveying section 22 rotate an endless belt to convey the packaging bodies 50 on the belt. The first conveying section 21 is disposed upstream of the image acquisition device 3 in the conveying direction X of the packaging bodies 50. The second conveying section 22 is disposed downstream of the image acquisition device 3 in the conveying direction X of the packaging bodies 50. The conveying unit 2 forms a gap O between the first conveying section 21 and the second conveying section 22, which serves as a space between the light-emitting section 31 and the light-receiving section 32. The distance between the first conveying section 21 and the second conveying section 22, which is the gap O, is a distance that does not affect the transfer from the first conveying section 21 to the second conveying section 22. With this configuration, the conveying unit 2 conveys the packaging bodies 50 into the space between the light-emitting section 31 and the light-receiving section 32.

[0023] The image acquisition device 3 acquires two-dimensional temperature information of the sealed portion 52 of the package 50 transported by the transport unit 2 as an image.

[0024] The light emitting unit 31 two-dimensionally irradiates light onto the entire sealed portion 52 of the package 50 transported by the transport unit 2. The light emitting unit 31 may irradiate light onto the package 50 being transported by the transport unit 2 in the gap O between the first transport unit 21 and the second transport unit 22, or may irradiate light onto the package 50 that has stopped temporarily on the transport unit 2.

[0025] As light is emitted from the light emitting section 31, the light receiving section 32 receives heat radiation from the entire seal section 52 of the package 50 in a two-dimensional manner.

[0026] Here, the light emitting section 31 and the light receiving section 32 will be described in detail.

[0027] As described above, the packaging material 51 of the package 50 is made of an aluminum-deposited film or a film laminated with aluminum foil, and contains at least aluminum. Therefore, the light-emitting unit 31 of the inspection device 1 of this embodiment irradiates one side of the sealed portion 52 of the package 50, which has a predetermined initial temperature, with light having a wavelength at least that is absorbed by aluminum. The aluminum foil 51b of the packaging material 51 (see FIG. 3 ) absorbs the light irradiated by the light-emitting unit 31 and converts the light energy into thermal energy. Heat generated in the aluminum foil 51b of the packaging material 51 is transmitted between and through the surfaces of each layer and reaches the surface of the packaging material 51. The packaging material 51 then radiates light due to thermal radiation from its surface. This light radiation is radiated with a spectrum based on the so-called Planck radiation law and is received by the light-receiving unit 32. The light-receiving unit 32 receives thermal radiation information two-dimensionally.

[0028] That is, when light is irradiated onto one side of the sealed portion 52, which has a certain initial temperature, the light is absorbed by the aluminum foil 51b inside the sealed portion 52, converting the light energy into thermal energy. The heat is then transferred to the other side through the surfaces of the layers, forming a temperature distribution on that surface. That is, after light is irradiated onto one side of the sealed portion 52 at time 0, the temperature on the other side of the sealed portion 52 begins to rise rapidly, reaching a peak at time T. Thereafter, the temperature of the sealed portion 52 gradually decreases due to convection with the surrounding atmosphere and thermal radiation.

[0029] FIG. 4 is a graph showing the absorptance of aluminum. Aluminum has the absorption spectrum shown in FIG. 4. As shown in FIG. 4, aluminum effectively absorbs light at the peak of its absorptance for near-infrared rays, which is between 0.78 μm and 1.0 μm. Aluminum also has high absorptance for ultraviolet rays (below 0.38 μm) and visible light (between 0.38 μm and 0.78 μm). Aluminum's absorptance decreases at wavelengths of 1 μm or more. Therefore, it is desirable for the light-emitting unit 31 to emit at least one of ultraviolet rays, visible light, and near-infrared light. Therefore, the light-emitting unit 31 of this embodiment uses a halogen lamp capable of emitting light including at least ultraviolet rays, visible light, and near-infrared light. Halogen lamps generally emit light with wavelengths longer than visible light and have a very broad emission spectrum. Although it depends on the lamp temperature, halogen lamps contain a large amount of light, particularly light with wavelengths longer than near-infrared light (e.g., 50% or more).

[0030] The light-emitting unit 31 is not limited to a halogen lamp, and a xenon lamp capable of emitting ultraviolet, visible, and near-infrared light may also be used. Xenon lamps generally have a broad emission spectrum across ultraviolet, visible, and near-infrared light, and multiple sharp emission spectra in the near-infrared range. Xenon lamps contain almost no wavelengths longer than near-infrared light (e.g., 5% or less). Such light with wavelengths longer than near-infrared light is also called heat rays, and heats surrounding components, affecting the miniaturization of the device and the selection of component parts. Therefore, it is practically preferable for the lamp not to contain light with wavelengths longer than near-infrared light.

[0031] Alternatively, the light-emitting unit 31 may be a near-infrared LED or near-infrared laser with a peak wavelength in the near-infrared region. The near-infrared LED or near-infrared laser has an emission spectrum peak in approximately the same wavelength band as the absorption spectrum peak of aluminum, allowing for highly efficient conversion of light energy into thermal energy. Furthermore, near-infrared LEDs or near-infrared lasers generally have a longer lifespan than halogen lamps or xenon lamps, which provides the advantage of longer replacement cycles when used in a continuously operating inspection device 1.

[0032] Furthermore, the light emitting unit 31 may be either a continuous light (DC light emission) or an intermittent light (pulse light emission). However, from the viewpoint of lifespan, it is preferable that it can be intermittently lit at about 1 Hz to 2 Hz. Specifically, this applies to lasers, LEDs, and xenon lamps.

[0033] Furthermore, when the light emitting unit 31 is continuously lit (DC light emission), an intermittent irradiation means (shutter) may be provided between the light emitting unit 31 and the packaging body 50 so that the packaging body 50 is intermittently lit.

[0034] In this embodiment, the surface temperature of the seal portion 52 may rise by a few degrees Celsius to 10 degrees Celsius. Although the temperature could be raised higher, a high-power light source would be required, which would be impractical in terms of the cost and size of the light source. If the ambient temperature of the inspection device 1 is approximately 20 to 30 degrees Celsius, the temperature would be approximately 295 to 315 K (273 degrees Celsius + 20 to 30 degrees Celsius + several degrees Celsius to 10 degrees Celsius). Furthermore, it is known that thermal radiation equivalent to 300 K has a wavelength of approximately 3 μm or more according to Planck's law. Therefore, light emitted by thermal radiation from the seal portion 52 of the package 50 has a wavelength of approximately 3 μm or more according to Planck's law. That is, the light receiving unit 32 receives light having a wavelength of 3 μm or more.

[0035] By making the wavelength of the light-emitting unit 31 and the wavelength of the light-receiving unit 32 different in this way, the light from the light-emitting unit 31 is not received by the light-receiving unit 32 and does not become noise in the light-receiving unit 32, making it possible to obtain a good light-receiving signal.

[0036] The atmospheric transmission spectrum includes wavelength bands with high atmospheric transmittance, called atmospheric windows. These bands are preferably used when measuring in the atmosphere. Examples include MWIR (Middle Wavelength Infrared Radiation), which is the wavelength band from 3 to 6 μm, and LWIR (Long Wavelength Infrared Radiation), which is the wavelength band from 8 to 14 μm.

[0037] Furthermore, since the thermal radiation spectrum at about 300 K has a peak at about 10 μm, it is preferable to use the atmospheric window of the LWIR for more sensitive measurements.

[0038] Therefore, in this embodiment, the light receiving unit 32 uses an infrared receiving element that receives LWIR. There are two types of infrared receiving elements: a cooled type that requires cooling to extremely low temperatures and is highly sensitive, and an uncooled type that can operate at room temperature. In this embodiment, the light receiving unit 32 uses an uncooled type infrared receiving element, which is practically low cost.

[0039] The light emitting unit 31 may be any of a point type light source, a line type light source, and an area type light source, as long as it can two-dimensionally illuminate the entire seal portion 52.

[0040] FIG. 5 is a diagram showing an example of a point-type light source when illuminating a package 50 being conveyed, and FIG. 6 is a diagram showing an example of a point-type light source when illuminating a stationary package 50. As shown in FIGS. 5 and 6, the point-type light source irradiates the seal portion 52 in a point-like manner. As shown in FIG. 5, when illuminating a package 50 being conveyed, the light emitting unit 31 irradiates the point-type light source two-dimensionally via an optical system that scans the seal portion 52 one-dimensionally. As shown in FIG. 6, when illuminating a stationary package 50, the light emitting unit 31 irradiates the point-type light source two-dimensionally via an optical system that scans the seal portion 52 two-dimensionally.

[0041] FIG. 7 is a diagram showing an example of a line-type light source when illuminating a package 50 being conveyed, and FIG. 8 is a diagram showing an example of a line-type light source when illuminating a stationary package 50. As shown in FIGS. 7 and 8, the line-type light source irradiates the seal portion 52 in a line. The line-type light source may be a line-type light source formed by arranging point-type light sources in a single row or multiple rows, or may be a line-type light source that uses point-type light sources to create a line-shaped irradiation pattern via an optical system. As shown in FIG. 7, when illuminating a package 50 being conveyed, the light emitting unit 31 two-dimensionally irradiates the seal portion 52 using a line-type light source that is longer than the width (longitudinal width) of the seal portion 52. As shown in FIG. 8, when illuminating a stationary package 50, the light emitting unit 31 two-dimensionally irradiates the seal portion 52 using an optical system that scans the seal portion 52 one-dimensionally using a line-type light source that is slightly longer than the lateral width of the seal portion 52.

[0042] FIG. 9 is a diagram showing an example of an area-type light source when illuminating a package 50 being conveyed, and FIG. 10 is a diagram showing an example of an area-type light source when illuminating a stationary package 50. As shown in FIGS. 9 and 10, the area-type light source irradiates the seal portion 52 in an area-like manner all at once. The area-type light source may be an area-type light source formed by arranging point-type light sources vertically and horizontally, an area-type light source formed by arranging multiple line-type light sources in an area-like manner, or a light source that combines these with an optical system to create an area-like irradiation pattern. As shown in FIG. 9, when illuminating a package 50 being conveyed, the light emitting unit 31 irradiates the package 50 in an area-like manner using the area-type light source. As shown in FIG. 10, when illuminating a stationary package 50, the light emitting unit 31 irradiates the package 50 in an area-like manner using the area-type light source.

[0043] On the other hand, the light receiving section 32 may be any of a point-type light receiving element, a line-type light receiving element, and an area-type light receiving element, as long as it two-dimensionally receives heat radiation from the entire seal portion 52 as a result of light irradiation. A thermopile or the like is used as the point-type light receiving element. A microbolometer or the like is used as the area-type light receiving element.

[0044] Fig. 11 is a diagram showing an example of a point-type light-receiving element when receiving thermal radiation from a package 50 being transported, and Fig. 12 is a diagram showing an example of a point-type light-receiving element when receiving thermal radiation from a stationary package 50. As shown in Fig. 11, when receiving thermal radiation from a package 50 being transported, the light-receiving unit 32 receives light two-dimensionally with the point-type light-receiving element via an optical system that one-dimensionally scans the seal portion 52. As shown in Fig. 12, when receiving thermal radiation from a stationary package 50, the light-receiving unit 32 receives light two-dimensionally with the point-type light-receiving element via an optical system that two-dimensionally scans the seal portion 52.

[0045] Fig. 13 is a diagram showing an example of a line-type light-receiving element when receiving thermal radiation from a package 50 being conveyed, and Fig. 14 is a diagram showing an example of a line-type light-receiving element when receiving thermal radiation from a stationary package 50. As shown in Fig. 13, when receiving thermal radiation from a package 50 being conveyed, the light-receiving unit 32 receives light two-dimensionally with a line-type light-receiving element longer than the seal width. As shown in Fig. 14, when receiving thermal radiation from a stationary package 50, the light-receiving unit 32 receives light two-dimensionally with a line-type light-receiving element slightly longer than the short side width of the seal portion 52 via an optical system that scans the seal portion 52 one-dimensionally.

[0046] Fig. 15 is a diagram showing an example of an area-type light-receiving element when receiving thermal radiation from a package 50 being transported, and Fig. 16 is a diagram showing an example of an area-type light-receiving element when receiving thermal radiation from a stationary package 50. As shown in Fig. 15, when receiving thermal radiation from a package 50 being transported, the light-receiving unit 32 receives light from the entire seal portion 52 with the area-type light-receiving element. As shown in Fig. 16, when receiving thermal radiation from a stationary package 50, the light-receiving unit 32 receives light from the entire seal portion 52 with the area-type light-receiving element.

[0047] As described above, there are various configurations for the light-emitting unit 31 that irradiates the entire sealed portion 52 with light and the light-receiving unit 32 that receives thermal radiation from the entire sealed portion 52. In this embodiment, the light-emitting unit 31 is an area-type light-emitting source, and the light-receiving unit 32 is an area-type light-receiving element. By combining an area-type light-emitting source and an area-type light-receiving element in this manner, it is possible to irradiate and receive light all at once on the entire sealed portion 52, regardless of whether the package 50 is being transported or is stationary, regardless of the transport state. Furthermore, an area-type light-emitting source and an area-type light-receiving element in which point-type light-emitting sources (specifically, LEDs) are arranged vertically and horizontally does not require an optical system for one-dimensional or two-dimensional scanning, i.e., no moving parts, and high-quality images can be acquired without being affected by vibration.

[0048] Next, the positional relationship between the light emitting section 31 and the light receiving section 32 will be described in detail.

[0049] As described above, the light-receiving unit 32 does not directly receive light that is irradiated from the light-emitting unit 31 and passes through the seal portion 52 of the packaging material 51, or light that is reflected from the seal portion 52. The light-receiving unit 32 receives light that is emitted by thermal radiation from the surface of the packaging material 51 due to the light irradiated from the light-emitting unit 31. In other words, the light-emitting unit 31 and the light-receiving unit 32 are not restricted in their arrangement based on the transmission or specular reflection of light. This increases the degree of freedom in the layout of the light-emitting unit 31 and the light-receiving unit 32.

[0050] 17 is a diagram showing a first layout example of the light-emitting unit 31 and the light-receiving unit 32. In the example shown in Fig. 17, the light-receiving unit 32 is installed with its optical axis tilted with respect to the light-emitting unit 31 and the seal portion 52 of the packaging material 51, which are surfaces approximately parallel to the conveyance direction X. By installing the light-receiving unit 32 with its optical axis tilted with respect to the seal portion 52 of the packaging material 51 in this way, it is possible to prevent the light-receiving unit 32 itself from being reflected in the image.

[0051] 17, the packaging body 50 has a bulge near the sealed portion 52 thereof because the packaging body 50 contains an article inside the packaging material 51. Therefore, while the sealed portion 52 is substantially parallel to the conveyance direction X, the area near the sealed portion 52 is inclined relative to the conveyance direction X. Therefore, in the example shown in FIG. 17, the light receiving unit 32 is installed with its optical axis inclined in the same direction as the inclination of the packaging material 51 near the sealed portion 52, rather than at an angle perpendicular to the inclination of the packaging material 51 near the sealed portion 52.

[0052] 18 is a diagram showing a second layout example of the light-emitting unit 31 and the light-receiving unit 32. In the example shown in Fig. 18, the light-receiving unit 32 may be arranged at a position perpendicular to, but not inclined from, the sealing unit 52, which is a surface substantially parallel to the conveying direction X, provided that there is no effect of reflection of the light-receiving unit 32 itself.

[0053] 19 is a diagram showing a third layout example of the light-emitting unit 31 and the light-receiving unit 32. In the example shown in Fig. 19, in addition to the second layout example of Fig. 18, the light-emitting unit 31 is installed with its optical axis tilted with respect to the seal portion 52 of the packaging material 51, which is a surface approximately parallel to the conveyance direction X, and the light-receiving unit 32.

[0054] Next, the control device 4 will be described. The control device 4 controls the entire inspection device 1. Here, FIG. 20 is a block diagram showing the hardware configuration of the control device 4. As shown in FIG. 20, the control device 4 includes a CPU (Central Processing Unit) 41, a ROM (Read Only Memory) 42, a RAM (Random Access Memory) 43, and a HDD 44. The control device 4 uses the RAM 43 as a work memory and drives and controls each part of the transport unit 2 and the image acquisition device 3 in accordance with programs pre-stored in the ROM 42 and the HDD 44. The control device 4 can be, for example, a personal computer (desktop or laptop).

[0055] The program executed by the control device 4 of this embodiment may be configured to be provided by being recorded in an installable or executable file format on a computer-readable recording medium such as a CD-ROM, a flexible disk (FD), a CD-R, or a DVD (Digital Versatile Disk).

[0056] Furthermore, the program executed by the control device 4 of this embodiment may be stored on a computer connected to a network such as the Internet and provided by being downloaded via the network. Also, the program executed by the control device 4 of this embodiment may be provided or distributed via a network such as the Internet.

[0057] The control device 4 determines whether the seal portion 52 of the package 50 is good or bad based on the two-dimensional image captured by the image capture device 3.

[0058] Next, the function of the control device 4 will be described.

[0059] Fig. 21 is a functional block diagram showing the functions of the control device 4. As shown in Fig. 21, the control device 4 functions as a control unit 401, a two-dimensional image acquisition unit 402, and a pass / fail determination unit 403 as a result of the CPU 41 operating in accordance with a program.

[0060] The control unit 401 controls the light emission of the light emitting unit 31 and the light reception of the light receiving unit 32 of the image acquisition device 3. The control unit 401 also controls the driving of the first transport unit 21 and the second transport unit 22 of the transport unit 2.

[0061] The two-dimensional image acquisition unit 402 acquires two-dimensional temperature information of the seal portion 52 of the package 50 as an image from the thermal radiation information received two-dimensionally by the light receiving unit 32. In other words, the two-dimensional image acquisition unit 402 converts the light information into temperature information and acquires a temperature image. This is also called thermography (thermal image). The two-dimensional image acquisition unit 402 may be provided in an infrared camera in which the light receiving unit 32 is an uncooled microbolometer.

[0062] The quality determination unit 403 determines whether the seal portion 52 of the package 50 is in a good or bad state, i.e., good or bad, based on the two-dimensional image having temperature information. The quality determination unit 403 performs various known image processing on the two-dimensional image to reveal any bad states.

[0063] As described above, when the seal portion 52 of the package 50 is defective, the heat capacity of the seal portion 52 changes compared to when it is in a good state. For example, a jammed seal is a defect in which an item is jammed in the seal portion 52, and the item is sealed between the packaging materials 51. Therefore, a new layer is formed by the item, slowing down heat transfer. A perforated seal is a defect in which a path is created in the seal portion 52 that allows the item to leak to the outside. The high thermal resistance of the air present between the packaging materials 51 slows down heat transfer. Thus, when the seal portion 52 of the package 50 is defective, the time it takes for heat to reach the surface of the seal portion 52 is delayed, resulting in a temperature distribution on the surface. Therefore, the quality determination unit 403 can determine whether the package 50 is in a bad state, i.e., whether it is good or bad, based on the temperature distribution generated in the two-dimensional image containing temperature information.

[0064] Next, the quality determination of the seal portion 52 in the quality determination section 403 will be described.

[0065] Here, Fig. 22 is a graph showing an example of changes in surface temperature at positions in a good state and positions in a bad state, and Fig. 23 is a diagram showing a specific example of a two-dimensional image for determining the quality of the seal portion 52. The example shown in Fig. 23 shows a case where there is an air layer in the seal portion 52, which is a bad state. This simulates a situation seen when there is penetration or when contents containing air are caught in the seal portion.

[0066] In the example shown in Figure 22, when there is a seal portion 52 containing aluminum in both a good and a bad state, light is irradiated from one side by the light emitting unit 31 at time 0, and the temperature distribution of the surface on the other side is obtained at a certain time t.

[0067] The two-dimensional image shown in Fig. 23 was acquired at time A shown in Fig. 22. The image shown in Fig. 23 is a monochrome image in which white indicates high temperature and black indicates low temperature. As shown in Fig. 23, it can be seen that the location in the seal portion 52 that is in a defective state due to the presence of an air layer is darker than the surrounding area.

[0068] In the example shown in FIG. 22, the position in the good state reaches the peak temperature at time T. This time T is about 480 ms. This time varies depending on the type and thickness of the packaging material 51, but is approximately from several 100 ms to less than 1 s. On the other hand, as shown in FIG. 22, the position in the bad state is about 580 ms. The position in the bad state reaches the peak temperature after time T, and the peak temperatures of both the good state and the bad state are almost the same.

[0069] Here, FIG. 24 is a graph exemplarily showing the difference value of the surface temperature over time. The graph shown in FIG. 24 is the result of subtracting the surface temperature at the position in the bad state from the surface temperature at the position in the good state. As shown in FIG. 24, when 0 < t < T, the value obtained by subtracting the surface temperature at the position in the bad state from the surface temperature at the position in the good state is a positive value. That is, as shown by the dotted line in FIG. 24, when looking at a certain time A, it can be seen that the temperature is higher in the good state than in the bad state. The time A shown in FIG. 24 is about 80 ms, and FIG. 23 is a two-dimensional image obtained at time A.

[0070] That is, it can be seen that the time change of the surface temperature of the seal part 52 is different between the good state and the bad state, and a large temperature difference that can be detected occurs at a certain time. Note that the good state and the bad state reach almost the same peak temperature as time passes, and the temperature difference becomes small after the peak.

[0071] From the above, it can be seen that in the two-dimensional image obtained when 0 < t < T, when there is penetration or biting-in, a temperature distribution in which the temperature of that part is lower than the surroundings can be obtained. The pass / fail determination unit 403 can detect a bad state by detecting the absolute values of the temperatures in the good state and the bad state.

[0072] As shown in FIG. 24, the temperature difference becomes particularly large when 0 < t < T / 2. When using the two-dimensional image obtained at 0 < t < T / 2, there is an advantage that the inspection time in the inspection apparatus 1 is shortened as t becomes smaller. When using the two-dimensional image obtained at 0 < t < T / 2, it is necessary to perform irradiation and light reception at high speed. When one-dimensional or two-dimensional scanning is required, the time constraint becomes severe. Therefore, it is more preferable to perform irradiation and light reception on the entire sealing portion 52 at once.

[0073] However, depending on the defective state, the thermal resistance may become small and the temperature may rise higher than the surroundings. Even in such a case, the pass / fail determination unit 403 can detect the defective state of the sealing portion 52 by observing the difference between the good state and the defective state.

[0074] Hereinafter, a case where the temperature is lower than the surroundings (when there is an air layer) in the case of a defective state will be specifically described.

[0075] The pass / fail determination unit 403 determines the pass / fail of the sealing portion 52 from a plurality of two-dimensional images. More specifically, the pass / fail determination unit 403 determines the pass / fail of the sealing portion 52 from a plurality of two-dimensional images among the information received at a certain time interval. By using a plurality of two-dimensional images in this way, the pass / fail determination accuracy can be improved.

[0076] However, when receiving light for a plurality of images, it is necessary that all the two-dimensional images are within the field of view of the light receiving unit 32. There is no problem when the package 50 is stopped. However, when the package 50 is being conveyed, it is necessary to widen the field of view, adjust the conveyance speed, or follow the package 50 to receive light so that it is within the field of view of the light receiving unit 32.

[0077] For simplicity, the pass / fail determination by the pass / fail determination unit 403 in the case of using two two-dimensional images will be described. Here, the time t at which the two-dimensional image acquisition unit 402 acquires the two two-dimensional images satisfies t < T. More specifically, the two-dimensional image acquisition unit 402 acquires a two-dimensional image at a time S that satisfies at least one t < 0, and acquires a two-dimensional image at a time U that satisfies at least one 0 < t < T.

[0078] The pass / fail determination unit 403 can acquire one two-dimensional image at a time S that satisfies 0 < t < T, acquire another two-dimensional image at a time U that satisfies t > T, and perform differential image processing using the two images. At t > T, the peak temperature has been exceeded, and thereafter the temperature decreases due to atmospheric convection, but the temperature decrease time is much longer compared to the temperature rise time from 0 to T. Therefore, the temperature at time U can be regarded as being approximately equal to the peak temperature. Accordingly, the pass / fail determination unit 403 detects the difference between time S and time U to obtain the temperature difference (relative value) from the peak temperature. The pass / fail determination unit 403 regards it as a defective state when the temperature difference is larger than that in a good state. Note that it is preferable that time U is as close to time T as possible. Also, when an infrared camera with, for example, 30 fps is used as the light receiving unit 32, time S and time U may be two non-consecutive frames.

[0079] As described above, the pass / fail determination unit 403 can perform image processing using a plurality of images, such as differential processing or regression analysis processing, taking into account the non-uniformity of the initial temperature.

[0080] From the perspective of shortening the inspection time in the inspection apparatus 1, it is preferable that the time required for acquiring the two-dimensional image is as short as possible. That is, time S and time U are more preferably two consecutive frames than two non-consecutive frames.

[0081] When the good / bad determination unit 403 performs differential image processing using two two-dimensional images continuously acquired at times S and U that satisfy 0 < t < T, the rate of temperature increase with respect to time will be different because the temperature rises quickly in a good state and slowly in a bad state. Therefore, the good / bad determination unit 403 calculates the temperature increase difference (relative value) by taking the difference between time S and time U.

[0082] As described above, by causing the light emitting unit 31 to emit light at time 0 and continuously taking pictures at certain times S and U, the inspection time can be shortened.

[0083] Similarly, the case of good / bad determination by the good / bad determination unit 403 when using three two-dimensional images will be described.

[0084] The good / bad determination unit 403 performs regression analysis processing using three two-dimensional images continuously acquired at certain times S1, S2, and S3 that satisfy 0 < t < T. By performing regression analysis at times S1, S2, and S3, the good / bad determination unit 403 can analyze more accurately as the temperature change (relative value). As a simple example, a clear difference can be obtained between a bad state and a good state based on the slope by linear regression, that is, the rate of temperature increase per unit time.

[0085] The inspection device 1 determines whether the seal portion 52 of the package 50 is good or bad as described above. Further, after the inspection device 1 conveys the package 50 by the second conveyance unit 22 of the conveyance unit 2, the package 50 determined to be bad is excluded from the second conveyance unit 22 by a sorting means (rejector) not shown. On the other hand, the package 50 determined to be good is conveyed by the second conveyance unit 22 and boxed by a packing means (caser) not shown or manually.

[0086] According to this embodiment, in order to increase the temperature of the packaged product, a light source that allows the packaged product to absorb light energy and convert it into thermal energy is used. Considering spatial propagation, light energy is easier to control and has a higher layout freedom than thermal energy. In addition, since a light source that allows the packaged product to absorb light energy and convert it into thermal energy also has a small thermal impact on surrounding members, it is easy to place it close to peripheral members such as the light emitting unit 31, the light receiving unit 32, and the conveying unit 2. Therefore, there is no need to use a heat source, and the heat of the heat source will not have an adverse effect on the peripheral members, so a high-quality temperature image can be obtained.

[0087] (Second Embodiment) Next, the second embodiment will be described.

[0088] The second embodiment is different from the first embodiment in that at least one two-dimensional image is acquired at a time t satisfying t < 0 and noise removal is performed. Hereinafter, in the description of the second embodiment, the description of the same parts as those in the first embodiment will be omitted, and the parts different from the first embodiment will be described.

[0089] The initial temperature of the seal portion 52 may vary depending on the location within the seal portion 52 due to the influence of the ambient temperature or the non-uniformity of the seal portion 52. In addition, the initial temperature of the seal portion 52 varies depending on the location of the light receiving element because there are variations in sensitivity for each pixel when a line-type light receiving element or an area-type light receiving element is used as the light receiving unit 32.

[0090] Therefore, in order to perform noise removal to exclude the influence of such locations, the pass / fail determination unit 403 may acquire at least one two-dimensional image before the light emitting unit 31 emits light, and perform differential image processing on the image after light emission, that is, the two-dimensional image acquired at a time t satisfying 0 < t < T. In this case, the time t when the two-dimensional image acquisition unit 402 acquires at least one two-dimensional image is t < 0. In this case, the acquisition of the two-dimensional image may be non-continuous. That is, the pass / fail determination unit 403 acquires at least one two-dimensional image at a time R satisfying t < 0 and performs noise removal.

[0091] Note that the pass / fail determination unit 403 may acquire a plurality of two-dimensional images at times Rn (n ≧ 2) that satisfy t < 0 for noise removal and perform average processing thereon.

[0092] Here, FIG. 25 is a diagram showing a specific example of a two-dimensional image related to the pass / fail determination of the seal portion by the pass / fail determination unit 403 according to the second embodiment. The example shown in FIG. 25 is an example of a two-dimensional image in which the pass / fail determination unit 403 performs image processing by regression analysis using a total of four consecutive two-dimensional images, namely, one two-dimensional image that satisfies t < 0 and three two-dimensional images that satisfy 0 < t < T, to make it easier to visualize.

[0093] The two-dimensional image shown in FIG. 25 has a higher contrast between the defective state and the good state, that is, the black part and the white part, than the two-dimensional image shown in FIG. 23.

[0094] Thus, according to the present embodiment, the pass / fail determination unit 403 can improve the determination accuracy of defects.

[0095] Note that in each embodiment, aluminum is applied as the substance that absorbs light energy, but the present invention is not limited thereto, and other metals, resins, etc. can be applied as long as they are substances that absorb light energy and convert light energy into heat energy.

[0096] Note that in each embodiment, what is called a retort pouch is applied as the packaging material 51 of the package 50, but the present invention is not limited thereto, and it can be applied to various packaging materials 51 that accommodate articles and seal the openings. For example, as the packaging material 51 of the package 50, a lid of a yogurt container, a container that encloses a medicine tablet, etc. can be mentioned.

[0097] Although the embodiments of the present invention have been described in detail above with reference to the drawings, the above-described embodiments are merely examples of the present invention, and the present invention is not limited to the configurations of the above-described embodiments. Changes in design within the scope of the present invention are also included in the present invention. [Explanation of symbols]

[0098] 1. Inspection equipment 3. Image acquisition device 31 Light-emitting part 32 Light receiving part 51 Packaging materials 52 Seal part 402 2D image acquisition unit 403 Good / bad judgement section [Prior art documents] [Patent documents]

[0099] [Patent Document 1] Japanese Patent Publication No. 2020-041840

Claims

1. a light emitting unit that irradiates a sealing unit that seals a packaging material containing a substance that absorbs light energy with light having at least a wavelength that is absorbed by the substance; a conveying unit that conveys the placed packaging material; a light receiving section that is located on the opposite side of the light emitting section across the conveying unit and receives heat radiation from the sealing section; a two-dimensional image acquisition unit that acquires temperature information of the sealing portion as a two-dimensional image from the information received by the light receiving unit; Equipped with an irradiation area where the light-emitting unit irradiates the sealing portion with light and a light-receiving area where the light-receiving unit receives the thermal radiation from the sealing portion at least partially overlap each other when viewed from a direction perpendicular to the irradiation area or the light-receiving area; the time t of the at least one two-dimensional image to be acquired is set to 0<t<T, where 0 is the time when the light emitting unit irradiates light onto one side of the seal portion where at least a portion of the irradiation area and the light receiving area overlap, and T is the time when the surface temperature of the other side of the seal portion where at least a portion of the irradiation area and the light receiving area overlap reaches a peak; An image acquisition device characterized by:

2. the light receiving unit does not directly receive light that is irradiated from the light emitting unit and transmitted through the sealing unit, and light that is irradiated from the light emitting unit and reflected by the sealing unit.

2. The image acquisition device according to claim 1.

3. The light emitting unit irradiates the sealing portion all at once, The light receiving unit collectively receives the heat radiation from at least the seal portion.

3. The image acquisition device according to claim 1 or 2.

4. The light emitting unit is an area type light emitting source in which point type light emitting sources are arranged vertically and horizontally.

4. The image acquisition device according to claim 3.

5. An image acquisition device according to any one of claims 1 to 4; a quality determination unit that determines the quality of the seal portion from the two-dimensional image acquired by the two-dimensional image acquisition unit; An inspection device comprising:

6. the quality determination unit determines the quality of the seal portion from a plurality of two-dimensional images.

6. The inspection device according to claim 5.

7. the quality determination unit determines the quality of the seal portion from a plurality of consecutive two-dimensional images among the information received by the two-dimensional image acquisition unit at a certain time interval.

7. The inspection device according to claim 6.

8. the quality determination unit sets a time t of at least one two-dimensional image acquired from the two-dimensional image acquisition unit to 0<t<T / 2; 8. The inspection device according to claim 5, wherein the inspection device comprises: a first electrode;

9. the quality determination unit sets a time t of the plurality of two-dimensional images acquired from the two-dimensional image acquisition unit to t<T / 2; 8. The inspection device according to claim 5, wherein the inspection device comprises: a first electrode;

10. the quality determination unit further sets the time t of at least one two-dimensional image acquired from the two-dimensional image acquisition unit to t<0, and performs noise removal based on the acquired two-dimensional image.

10. The inspection device according to claim 5, wherein the inspection device comprises: a first electrode;

11. A conveying step of placing a packaging material containing a substance that absorbs light energy and conveying it by a conveying unit; a light emitting step of irradiating a sealing portion that seals the packaging material with light having at least a wavelength that is absorbed by the substance from a light emitting unit; a light receiving step of receiving heat radiation from the sealing portion with a light receiving unit located on the opposite side of the light emitting unit across the conveying unit; a two-dimensional image acquisition step of acquiring temperature information of the sealing portion as a two-dimensional image from the information received in the light receiving step; Including, an irradiation area where the light emitting unit irradiates the sealing portion with light in the light emitting step and a light receiving area where the light receiving unit receives the thermal radiation from the sealing portion in the light receiving step at least partially overlap each other when viewed from a direction perpendicular to the irradiation area or the light receiving area; In the two-dimensional image acquisition step, when the time when the light emitting unit irradiates light to one side of the seal portion where at least a part of the irradiation area and the light receiving area overlap is defined as 0, and the time when the surface temperature of the other side of the seal portion where at least a part of the irradiation area and the light receiving area overlap reaches a peak is defined as T, the time t of at least one two-dimensional image to be acquired is defined as 0<t<T. An image acquisition method characterized by:

Images