Inspection device and inspection method

Abstract

An inspection device according to one embodiment of the present disclosure comprises: a light emission unit that is provided at a position that faces a target that includes a container that is formed from a material that has light-scattering properties and an object that is a gel or a gel-forming sol and is accommodated in the container and emits irradiation light that includes a wavelength that can pass through the container at the object; a light detection unit that is provided at a position that faces the target, detects detection light that is emitted from the object and passes through the container as the object is irradiated with the irradiation light, and outputs a detection signal that indicates detection results for the detection light; and a processing unit that is communicably connected to the light detection unit and estimates a solidification parameter that indicates a degree of solidification for the object on the basis of an optical parameter for the object that is obtained from the detection results.

Description

Inspection Device and Inspection Method

[0001] The present disclosure relates to an inspection device and an inspection method. This application claims priority based on Japanese Application No. 2024-160757 filed on September 18, 2024, and incorporates all the descriptions described in the above Japanese application.

[0002] For example, Patent Document 1 discloses a method for objectively and non-destructively inspecting the quality of a gel-like or gel-forming sol-like object using an optical technique. In this method, the object is irradiated with coherent light, and the quality of the object, such as its gel state or sol-gel state change, is evaluated from the state of the speckle pattern that appears when the light forms an image on a rough surface.

[0003] International Publication No. 2003 / 087790

[0004] Conventionally, when producing an object such as tofu, in the process of coagulating the object from a sol state to a gel state, the quality of the object, such as the degree of coagulation, has been managed based on the intuition and experience of workers. However, such management of the quality of an object relying on the intuition and experience of workers can lead to instability in the quality of the object. When an operation occurs to directly check the quality of the object by opening the container, a problem of manufacturing loss can also occur.

[0005] On the other hand, in the method of Patent Document 1 for inspecting the quality of an object using an optical technique, the quality of the object can be efficiently and objectively inspected without relying on the intuition and experience of workers, so the above-mentioned problems can be solved. However, in the method of Patent Document 1, based on the principle of evaluating the quality of an object based on changes in the speckle pattern, it is premised on using a vibration device that applies an external force to the object in order to obtain changes in the speckle pattern, so there is a problem that the device configuration becomes complicated. If a vibration device is not used, it is assumed that it will be difficult to detect changes in the speckle pattern and it will be difficult to accurately evaluate the quality of the object.

[0006] The present disclosure provides an inspection device and an inspection method that can accurately and efficiently inspect the quality of an object with a simple configuration.

[0007] The inspection apparatus of the present disclosure is an inspection apparatus comprising: [1] "a light emission unit positioned facing an object including a container made of a light-scattering material and a gel-like or gel-forming sol-like object contained in the container, which emits irradiation light including a wavelength that can penetrate the container toward the object; a light detection unit positioned facing the object, which detects detection light emitted from the object and transmitted through the container in conjunction with the irradiation of the object with the irradiation light, and outputs a detection signal indicating the detection result of the detection light; and a processing unit that is communicably connected to the light detection unit and estimates solidification parameters indicating the degree of solidification of the object based on the optical parameters of the object obtained from the detection result."

[0008] The inventors of this invention have diligently studied methods for inspecting the quality of gel-like or gel-forming sol-like objects using optical techniques, and have found a significant correlation between the optical parameters of an object, obtained from the detection results of detection light emitted from the object in response to irradiation with light, and solidification parameters, which indicate the degree of solidification of the object. Therefore, the above inspection device estimates the solidification parameters, which indicate the degree of solidification of the object, based on the optical parameters obtained from the detection results of the detection light. In this case, unlike when the degree of solidification of an object is evaluated based on the intuition and experience of the operator, the degree of solidification of the object can be evaluated non-destructively and objectively, making it possible to efficiently inspect the quality of the object. When inspecting the quality of an object using the correlation between optical parameters and solidification parameters, as in the above inspection device, unlike when inspecting the quality of an object using changes in the state of the speckle pattern, as in Patent Document 1, it is possible to accurately inspect the quality of an object with a simple configuration without using an excitation device to obtain changes in the speckle pattern. As with the inspection device described above, when the container holding the object is made of a light-scattering material, at least one of the irradiated light and the detection light can be diffused within the container as it passes through, allowing it to reach the object more reliably. This allows for more reliable detection of the detection light, which contains information about the object's internal structure, enabling a non-destructive and accurate evaluation of the object's degree of solidification based on the detection result of the detection light.

[0009] The inspection apparatus of the present disclosure may also be [2] "the inspection apparatus described in [1] above, wherein the light emission unit emits pulsed light as the irradiation light toward the object." In this case, optical parameters, which are internal information of the object, can be accurately determined by time-resolved spectroscopy (TRS method) that utilizes the time-resolved waveform of the detected light. When using the TRS method which is based on pulsed light, due to its measurement principle, even when the irradiation light is irradiated onto the object through a container, it is less affected by the container and has the advantage of being able to easily extract internal information (optical parameters) of the object inside the container. When pulsed light is used as the irradiation light in this way, there is an advantage that optical parameters that have a high correlation with the solidification parameters can be calculated, and there is also an advantage that even when the light intensity of the detected light is small, the optical parameters can be accurately calculated with the light emission unit and the light detection unit at a certain distance from the object. Therefore, with the above configuration, the optical parameters, which are internal information of the object, can be calculated with high accuracy using the TRS method, and thus the solidification parameters based on the optical parameters can be estimated with high accuracy.

[0010] The inspection apparatus of the present disclosure may also be [3] "the inspection apparatus according to [1] or [2] above, wherein the object includes a film that closes the opening of the container into which the object is exposed, the film is made of a material that can transmit at least one of the irradiation light and the detection light, and the light reflectance to at least one of the irradiation light and the detection light is higher than that of the container, and the light emission unit and the light detection unit are each positioned to face the film or the container." In the manufacturing process of the object, it is conceivable that the object flows through the production line with the opening of the container closed by the film. With the configuration of [3] above, even with the opening of the container closed by the film, irradiation light can be applied to the object through the film or container and detection light can be applied to the object without removing the film. This makes it easy to estimate the solidification parameters based on the optical parameters obtained from the detection result of the detection light.

[0011] The inspection apparatus of the present disclosure may also be [4] "the inspection apparatus according to any one of [1] to [3] above, wherein the light emitting unit and the light detection unit are arranged in a position facing the container and are adjacent to each other." In this case, the irradiation light emitted from the light emitting unit passes through the container and irradiates the object. Of the irradiation light irradiated onto the object, the reflected light that propagates inside the object and is reflected by the object is emitted from the object as detection light, passes through the container and is detected by the light detection unit. In this way, even when a reflective measurement that detects the detection light reflected from the object is performed through the container, the solidification parameters indicating the solidification state of the object can be accurately estimated based on the optical parameters obtained from the detection result of the detection light.

[0012] The inspection apparatus of the present disclosure may also be [5] "the inspection apparatus according to any one of [1] to [3] above, wherein the light detection unit is located on the opposite side of the object from the light emission unit." In this case, of the irradiation light emitted from the light emission unit and irradiated onto the object, the transmitted light that passes through the object is emitted from the object as detection light and detected by the light detection unit located on the opposite side of the light emission unit. Even when performing a transmission-type measurement in which detection light that has passed through the object is detected in this manner, the solidification parameters indicating the solidification state of the object can be accurately estimated based on the optical parameters obtained from the detection result of the detection light.

[0013] The inspection apparatus of the present disclosure may also be [6] "the inspection apparatus according to any one of [1] to [5] above, wherein at least one of the light emitting unit and the light detection unit is in contact with the object." In this case, the risk of a portion of the irradiation light emitted from the light emitting unit being detected as stray light by the light detection unit can be reduced. As a result, optical parameters obtained from the detection result of the detected light can be calculated with high accuracy, and solidification parameters can be estimated with high accuracy based on the optical parameters.

[0014] The inspection apparatus of the present disclosure may also be [7] "the inspection apparatus according to any one of [1] to [5] above, wherein at least one of the light emitting unit and the light detection unit is located at a predetermined distance from the object." Even when at least one of the light emitting unit and the light detection unit is located away from the object, the optical parameters obtained from the detection result of the detected light can be calculated with high accuracy, and the solidification parameters can be estimated with high accuracy based on the optical parameters. Compared to the configuration of [7] above, which assumes contact between the light emitting unit and the light detection unit with the object, the irradiation of the object flowing on the manufacturing line with irradiation light and the detection of the detected light can be easily performed.

[0015] The inspection apparatus of the present disclosure may also be [8] "the inspection apparatus according to any one of [1] to [7] above, wherein the container includes a container top surface having an opening formed therein through which the object is exposed, and a container bottom surface located on the opposite side of the container top surface, and at least one of the light emitting unit and the light detecting unit is positioned facing the container bottom surface." During the manufacturing process of an object, bubbles may be generated inside the container when the object is solidified inside the container. Such bubbles can change the direction of light propagation in an unintended direction, which can reduce the accuracy of the detection result of the detected light. However, such bubbles tend to float upward inside the container and are unlikely to form near the container bottom surface. In the configuration of [8] above, at least one of irradiating the object with light and detecting the detected light from the object can be performed through the container bottom surface where bubbles are unlikely to form. This reduces the risk of reduced accuracy of the detection result of the detected light due to bubble formation. As a result, solidification parameters can be accurately estimated based on the optical parameters obtained from the detection result of the detected light.

[0016] The inspection apparatus of the present disclosure may also be the inspection apparatus according to any one of [1] to [8] above, which includes: [9] "an optical parameter calculation unit that calculates the optical parameters of the object using the detection results; a storage unit that stores correlation information showing the correlation between the optical parameters and the solidification parameters; and a solidification parameter estimation unit that converts the optical parameters into the solidification parameters using the correlation information." In this case, the solidification parameters based on the optical parameters can be easily estimated using the pre-stored correlation information.

[0017] The inspection apparatus of the present disclosure may also be the inspection apparatus according to any one of [1] to [9] above, wherein the optical parameters include at least one of the equivalent scattering coefficient, average optical path length, light intensity, counting rate, and the nth moment of the time response waveform. Based on such optical parameters, the solidification parameters can be estimated with high accuracy.

[0018] The inspection apparatus of the present disclosure may also be

[11] "the inspection apparatus according to any one of [1] to

[10] above, wherein the solidification parameter includes at least one of viscosity, solid content concentration, and water retention rate." Using such solidification parameters as indicators, the degree of solidification of an object can be evaluated with high accuracy.

[0019] The inspection method of the present disclosure is

[12] "an inspection method comprising: emitting irradiation light including a wavelength that can penetrate the container toward an object, which includes a container formed of a light-scattering material and a gel-like or gel-forming sol-like object contained in the container; detecting detection light emitted from the object and transmitted through the container in conjunction with the irradiation of the object with the irradiation light, and outputting a detection signal indicating the detection result of the detection light; and estimating solidification parameters indicating the degree of solidification of the object based on the optical parameters of the object obtained from the detection result." According to this inspection method, as described above, it is possible to inspect the quality of an object accurately and efficiently with a simple configuration.

[0020] According to this disclosure, the quality of an object can be inspected accurately and efficiently with a simple configuration.

[0021] Figure 1 is a schematic diagram showing the configuration of the inspection apparatus of the first embodiment. Figure 2 is an enlarged perspective view showing the transport section of the inspection apparatus of Figure 1. Figure 3 is a cross-sectional view of the transport section along the line III-III in Figure 2. Figure 4 is a diagram showing the hardware configuration of the processing section of the inspection apparatus of Figure 1. Figure 5 is a diagram showing the functional configuration of the processing section of Figure 4. Figure 6 is a diagram showing the conditions of experimental samples for conducting an experiment to confirm the correlation between optical parameters and solidification parameters using the inspection apparatus of Figure 1. Figure 7(a) is a diagram showing the viscosity of each experimental sample in Figure 6. Figure 7(b) is a diagram showing the water retention rate of each experimental sample in Figure 6. Figure 7(c) is a diagram showing the solid content concentration of each experimental sample in Figure 6. Figure 8(a) is an experimental result showing the correlation coefficient between the equivalent scattering coefficient obtained when an object is irradiated with light in the first wavelength region using the inspection apparatus of Figure 1 and the solidification parameter. Figure 8(b) is an experimental result showing the correlation coefficient between the equivalent scattering coefficient obtained when an object is irradiated with light in the second wavelength region using the inspection apparatus of Figure 1 and the solidification parameter. Figure 9(a) shows experimental results showing the correlation coefficient between the average optical path length and the solidification parameter obtained when the object is irradiated with light in the first wavelength region using the inspection apparatus of Figure 1. Figure 9(b) shows experimental results showing the correlation coefficient between the average optical path length and the solidification parameter obtained when the object is irradiated with light in the second wavelength region using the inspection apparatus of Figure 1. Figure 10(a) shows experimental results showing the correlation coefficient between the light intensity obtained when the object is irradiated with light in the first wavelength region using the inspection apparatus of Figure 1 and the solidification parameter. Figure 10(b) shows experimental results showing the correlation coefficient between the light intensity obtained when the object is irradiated with light in the second wavelength region using the inspection apparatus of Figure 1 and the solidification parameter. Figure 11 shows experimental results showing the correlation coefficient between the counting rate obtained when the object is irradiated with light of three wavelengths using the inspection apparatus of Figure 1 and the solidification parameter. Figure 12 is a graph showing the correlation between the equivalent scattering coefficient and viscosity obtained from the experimental results of Figure 8(b). Figure 13 is a flowchart showing an example of an inspection method performed using the inspection apparatus of Figure 1. Figure 14 is a perspective view showing an inspection apparatus of modification 1 of the first embodiment. Figure 15 is a cross-sectional view of the transport section along the line XV-XV in Figure 14.Figure 16 is a perspective view showing an inspection apparatus of modification 2 of the first embodiment. Figure 17 is a cross-sectional view of the transport section along the line XVII-XVII in Figure 16. Figure 18 is a cross-sectional view showing an inspection apparatus of modification 3 of the first embodiment. Figure 19 is a cross-sectional view showing an inspection apparatus of modification 4 of the first embodiment. Figure 20(a) is a graph showing the device function waveform and the time response waveform of the detected light measured using the inspection apparatus of Figure 19. Figure 20(b) is an experimental result showing the correlation coefficient between the equivalent scattering coefficient and the solidification parameter obtained when the inspection apparatus of Figure 19 is irradiated with light in the second wavelength region onto an object. Figure 21(a) is an experimental result showing the correlation coefficient between the average optical path length and the solidification parameter obtained when the inspection apparatus of Figure 19 is irradiated with light in the second wavelength region onto an object. Figure 21(b) is an experimental result showing the correlation coefficient between the light intensity obtained and the solidification parameter obtained when the inspection apparatus of Figure 19 is irradiated with light in the second wavelength region onto an object. Figure 22 shows experimental results showing the correlation coefficient between the counting rate obtained when an object is irradiated with three wavelengths of light using the inspection apparatus of Figure 19, and the solidification parameter. Figure 23 is a cross-sectional view showing the inspection apparatus of modification 5 of the first embodiment. Figure 24(a) shows experimental results showing the correlation coefficient between the equivalent scattering coefficient obtained when an object is irradiated with light in the first wavelength region using the inspection apparatus of Figure 23, and the solidification parameter. Figure 24(b) shows experimental results showing the correlation coefficient between the equivalent scattering coefficient obtained when an object is irradiated with light in the second wavelength region using the inspection apparatus of Figure 23, and the solidification parameter. Figure 25 is a schematic diagram showing the configuration of the inspection apparatus of the second embodiment. Figure 26 is an enlarged perspective view showing the transport section of the inspection apparatus of Figure 25. Figure 27 is a cross-sectional view of the transport section along the line XXVII-XXVII in Figure 26. Figures 28(a), 28(b), and 28(c) are cross-sectional views showing modified arrangement patterns of the light-emitting and light-detecting units in the inspection apparatus of Figure 25. Figures 29(a), 29(b), and 29(c) are cross-sectional views showing yet another modified arrangement pattern of the light-emitting and light-detecting units in the inspection apparatus of Figure 25. Figure 30(a) shows experimental results showing the correlation coefficient between the equivalent scattering coefficient and the solidification parameter obtained when an object is irradiated with light in the first wavelength region using the inspection apparatus of Figure 25.Figure 30(b) shows experimental results showing the correlation coefficient between the equivalent scattering coefficient and the solidification parameter obtained when an object is irradiated with light in the second wavelength region using the inspection apparatus of Figure 25. Figure 31(a) shows experimental results showing the correlation coefficient between the average optical path length and the solidification parameter obtained when an object is irradiated with light in the second wavelength region using the inspection apparatus of Figure 25. Figure 31(b) shows experimental results showing the correlation coefficient between the light intensity obtained and the solidification parameter obtained when an object is irradiated with light in the second wavelength region using the inspection apparatus of Figure 25. Figure 32 shows experimental results showing the correlation coefficient between the counting rate and the solidification parameter obtained when an object is irradiated with light of three wavelengths using the inspection apparatus of Figure 25. Figure 33 is a perspective view showing the inspection apparatus of Modification 1 of the second embodiment. Figure 34 is a cross-sectional view of the transport section along the line XXXIV-XXXIV in Figure 33. Figure 35(a) is a cross-sectional view showing the inspection apparatus of Modification 2 of the second embodiment. Figure 35(b) is a cross-sectional view showing a further modification of the inspection apparatus in Figure 35(a). Figure 36 is a cross-sectional view showing the inspection apparatus of modification 3 of the second embodiment. Figure 37 is a cross-sectional view showing the inspection apparatus of modification 4 of the second embodiment. Figure 38 is an experimental result showing the correlation coefficient between the equivalent scattering coefficient obtained when the object is irradiated with light in the second wavelength region from outside the container using the inspection apparatus in Figure 37, and the equivalent scattering coefficient of the object itself (however, the correlation with the solidification parameter is known). Figure 39(a) is a cross-sectional view showing the inspection apparatus of the third embodiment. Figure 39(b) is a cross-sectional view showing a modification of the inspection apparatus in Figure 39(a). Figure 39(c) is a cross-sectional view showing a further modification of the inspection apparatus in Figure 39(a). Figure 40 is a cross-sectional view showing the inspection apparatus of the fourth embodiment. Figure 41 is a graph showing the correlation between the equivalent scattering coefficient obtained when the object is irradiated with light in the second wavelength region using the inspection apparatus in Figure 25, and the concentration of soy milk. Figure 42 is a graph showing the correlation between the scattering amplitude determined from the optical parameters and the concentration of soy milk. Figure 43 is a cross-sectional view showing the inspection apparatus of the fifth embodiment. Figure 44 is a cross-sectional view showing the inspection apparatus of modification 1 of the fifth embodiment. Figure 45 is a cross-sectional view showing the inspection apparatus of modification 2 of the fifth embodiment. Figure 46 is a cross-sectional view showing the inspection apparatus of the sixth embodiment. Figure 47 is a cross-sectional view showing the inspection apparatus of modification 1 of the sixth embodiment.Figure 48 is a cross-sectional view showing an inspection device of modification 2 of the sixth embodiment. Figure 49 is a plan view showing an inspection device of modification 3 of the sixth embodiment. Figure 50(a) is a side view showing a guide member of the inspection device of Figure 49. Figure 50(b) is a side view showing a modified example of the guide member of the inspection device of Figure 49. Figure 51 is a plan view showing an inspection device of modification 4 of the sixth embodiment. Figure 52 is a plan view showing the inspection device of Figure 51 after a certain amount of time has elapsed from the state shown in Figure 51. Figure 53 is a perspective view showing an inspection device of the seventh embodiment. Figure 54 is a cross-sectional view showing an inspection device of the eighth embodiment. Figure 55 is a cross-sectional view showing an inspection device of modification 1 of the eighth embodiment. Figure 56 is a cross-sectional view showing an inspection device of modification 2 of the eighth embodiment. Figure 57 is a plan view showing a light-shielding member provided in the inspection device of Figure 56. Figure 58 is a cross-sectional view showing an inspection device of modification 3 of the eighth embodiment. Figure 59 is a cross-sectional view showing an inspection device of modification 4 of the eighth embodiment.

[0022] Embodiments of this disclosure will be described in detail below with reference to the drawings. In each drawing, the same or corresponding parts are denoted by the same reference numerals, and redundant descriptions are omitted.

[0023] <First Embodiment> The inspection device 1 shown in Figure 1 inspects the quality of an object 12 contained in a container 10. Specifically, the inspection device 1 inspects the degree of solidification of the object 12 by detecting detection light Lb emitted from the object 12 in conjunction with irradiation with irradiation light La. The object 12 is a gel-like or gel-forming sol-like object used in fields such as food. A gel-like object 12 is an object that contains water, oil, organic solvents, or air as a dispersion medium, and also contains proteins, polysaccharides, or resins as dispersed particles, and is solid or gel-like in its final state. A gel-forming sol-like object 12 is a liquid or sol-like object in its normal state and has the property of gelling when stimulated from the outside. A gel-like object 12 also includes objects that change into a sol-like state when stimulated from the outside.

[0024] Examples of gel-like or gel-forming sol-like objects 12 are foods. Examples of gel-like foods include tofu, chawanmushi (steamed egg custard), pudding, jelly, yogurt, and konjac. Examples of gel-forming sol-like foods include soy milk, soy protein solution, raw eggs, egg tofu or raw ingredients for chawanmushi, milk, agar-agar beverages, and raw starch solution. In this embodiment, the case where object 12 is "tofu" will be described. Examples of "tofu" include various types of tofu such as silken tofu, packaged tofu, firm tofu, or soft tofu. However, object 12 may be a food other than those mentioned above, or it may be an object other than food.

[0025] As shown in Figure 1, the inspection device 1 includes, for example, a transport unit 2, a light emission unit 3, a light detection unit 4, a processing unit 5, a sorting unit 6, and an arm unit 7.

[0026] As shown in Figures 1 and 2, the transport unit 2 transports the object T in a predetermined transport direction D1. For example, the transport unit 2 transports the object T in the transport direction D1 at a constant speed toward the irradiation position of the irradiation light La from the light emission unit 3. As a result, the object T is scanned relative to the irradiation position of the irradiation light La. The transport direction D1 coincides, for example, with the horizontal direction.

[0027] The object T transported by the transport unit 2 includes an object 12, a container 10 that houses the object 12, and a film 11 that closes the container opening A (opening) from which the object 12 is exposed. The fact that the object 12 is housed in the container 10 means that at least a part of the object 12 is located in the internal space of the container 10. In other words, the fact that the object 12 is housed in the container 10 includes both the fact that the entire object 12 is located in the internal space of the container 10 and that a part of the object 12 protrudes upward from the container opening A.

[0028] As shown in Figure 2, the container 10 is, for example, a rectangular box-shaped container. As shown in Figure 3, the container 10 has a bottom P1, sides P2, and an edge P3. The bottom P1 is a bottom wall that intersects the vertical direction D2. The vertical direction D2 is a direction that intersects (orthogonal in one example) the transport direction D1, and coincides with, for example, the vertical direction. The bottom P1 includes the container bottom surface 10b that is placed on the transport unit 2. The sides P2 are side walls that rise from the edge of the bottom P1. The sides P2 extend from the edge of the bottom P1 along the vertical direction D2. The edge P3 is an overhang that protrudes outward from the sides P2 at the upper part opposite to the bottom P1. The edge P3 extends along the transport direction D1 and the left-right direction D3. The left-right direction D3 is a direction that intersects (orthogonal in one example) the transport direction D1 and the vertical direction D2, and coincides with, for example, the horizontal direction.

[0029] The container 10 includes a container top surface 10a with a container opening A formed therein, surrounded by a rim P3, and a container bottom surface 10b facing the opposite side from the container top surface 10a. The container top surface 10a and the container bottom surface 10b are planes that intersect (orthogonal in one example) the vertical direction D2 and are aligned along the vertical direction D2. An object 12 is exposed from the container opening A. The container bottom surface 10b is part of the bottom P1 and is placed on the transport unit 2.

[0030] The container 10 has light transmittance to the irradiated light La and the detected light Lb. Here, light transmittance means the property of transmitting at least a portion of each of the irradiated light La and the detected light Lb. The container 10 also has light scattering properties to the irradiated light La and the detected light Lb. Here, light scattering properties mean the property of changing the direction of at least a portion of each of the irradiated light La and the detected light Lb. Examples of materials for the container 10 having such light transmittance and light scattering properties include polypropylene (PP) or high-impact polystyrene (HIPS). It is suitable to use a colored (e.g., milky white) opaque material for the container 10. Such materials often contain dyes or pigments, and these fine particles have the effect of promoting light scattering.

[0031] As shown in Figures 2 and 3, the film 11 is attached to the upper surface 10a of the container so as to close the container opening A. The film 11 is in close contact with the upper surface 10a of the container when the container opening A is closed. Therefore, the object 12 is contained in a sealed state within the internal space surrounded by the film 11 and the container 10. The object 12 is in close contact with, for example, the bottom P1 of the container 10 without any gaps.

[0032] The object 12 may be positioned, for example, with a gap between it and the side P2 of the container 10 and the film 11, and part or all of the gap may be filled with another substance such as liquid. The object 12 may also be filled without any gaps in the internal space enclosed by the film 11 and the container 10. In other words, the object 12 may be in contact with the bottom P1, the side P2, and the film 11 without any gaps. The object T does not necessarily have to include the film 11, and part of the object 12 may be exposed to the outside through the container opening A.

[0033] The film 11 is formed from, for example, a transparent or translucent material. The film 11 is light-transmitting to the irradiation light La and the detection light Lb. The film 11 has a high light reflectivity to the irradiation light La and the detection light Lb. That is, the light reflectivity of the film 11 to the irradiation light La and the detection light Lb is higher than the light reflectivity of the container 10 to the irradiation light La and the detection light Lb. Examples of materials for the film 11 include polyethylene terephthalate (PET).

[0034] As shown in Figure 2, the conveying unit 2 includes at least one belt conveyor 21. The belt conveyor 21 includes a pair of rollers 211 and a pair of belts 212. Each of the pair of rollers 211 is, for example, a cylindrical member. Each roller 211 is positioned in a pair of positions separated from each other along the conveying direction D1. Each roller 211 is connected to a motor and rotates by the drive of the motor.

[0035] Each of the pair of belts 212 is, for example, an endless belt formed in an annular shape. Each belt 212 is arranged adjacent to each other with a gap G along the left-right direction D3 and is stretched over the pair of rollers 211. Each belt 212 is arranged to surround the pair of rollers 211 when viewed along the left-right direction D3. The width of the gap G along the left-right direction D3 is large enough to allow the irradiation light La from the light emission unit 3 and the detection light Lb toward the light detection unit 4 to pass through.

[0036] Each belt 212 includes a belt surface 212a that conveys the object T, and a belt surface 212b that faces the opposite side from the belt surface 212a. The bottom surface 10b of the container rests on the belt surface 212a. The belt surface 212a is in contact with the bottom surface 10b of the container. The belt surface 212b is in contact with the outer surface of each roller 211. Each belt 212 moves in the conveying direction D1 as each roller 211 rotates.

[0037] As shown in Figures 1 and 2, the light-emitting unit 3 and the light-detecting unit 4 are positioned facing the container 10 of the object T. Specifically, the light-emitting unit 3 and the light-detecting unit 4 are positioned facing the container bottom surface 10b in the vertical direction D2. The light-emitting unit 3 and the light-detecting unit 4 are, for example, positioned inside a pair of belts 212 and facing the container bottom surface 10b in the vertical direction D2 through a gap G between the pair of belts 212. The light-emitting unit 3 and the light-detecting unit 4 are, for example, arranged adjacent to each other along the transport direction D1. The distance between the light-detecting unit 4 and the light-emitting unit 3 along the transport direction D1 is shorter than the length of the object 12 along the transport direction D1.

[0038] As shown in Figure 3, the light-emitting unit 3 and the light-detecting unit 4 are separated by a predetermined distance d in the vertical direction D2 from, for example, the bottom surface 10b of the container. The distance d between the light-emitting unit 3 and the bottom surface 10b in the vertical direction D2 is, for example, the same as the distance d between the light-detecting unit 4 and the bottom surface 10b in the vertical direction D2. The distance d is, for example, 0 cm or more and 4 cm or less. By using an optical system including lenses and mirrors, the distance d can be made infinite. When the focus of the irradiated light La is aligned with the bottom surface 10b using an optical system, it may be possible to improve the measurement accuracy compared to when an optical system is not used. The distance d between the light-emitting unit 3 and the bottom surface 10b in the vertical direction D2 may be different from the distance d between the light-detecting unit 4 and the bottom surface 10b in the vertical direction D2. The emission surface of the light-emitting unit 3 from which the irradiated light La is emitted may be surrounded by a partition member such as a rubber member or a sponge member. The detection surface of the photodetector 4, where the detected light Lb is detected, may also be surrounded by a partition member such as a rubber or sponge. In this case, the risk of stray light components of the irradiated light La entering the photodetector 4 can be reduced.

[0039] The light emission unit 3 receives an electrical instruction signal φ1 from the processing unit 5 and irradiates the target object T with irradiation light La. The light emission unit 3 includes at least a light source that emits irradiation light La toward the object 12. Examples of light sources included in the light emission unit 3 include light-emitting diodes (LEDs), laser diodes (LDs), supercontinuum (SC) light sources, or wavelength-swept lasers. The mode of irradiation light La emitted from the light emission unit 3 is determined according to the method of measuring the internal information of the object 12 in the processing unit 5, and various types of light are employed, such as pulsed light, continuous wave (CW) light, intensity-modulated light, slit light, iPMSEL (integrable Phase Modulating Surface Emitting Lasers), structured light such as a Gray code pattern, or wavelength-modulated light. Methods for measuring the internal information of object 12 using irradiated light La include continuous wave spectroscopy (CW method), spatially resolved spectroscopy (SRS method), time-resolved spectroscopy (TRS method), phase modulation spectroscopy (PMS method), spatial frequency domain imaging (SFDI method), diffusion correlation spectroscopy (DCS method), speckle contrast spectroscopy (SCOS method), or swept source optical coherence tomography (SS OCT method). Optical parameters obtained by methods other than the TRS method that are related to coagulation parameters include the phase shift amount (Δψ), Brownian diffusion coefficient (D), Blood Flow index (BFi), the second-order correlation coefficient of light intensity (g²(τ)), and the coherence factor (β: g²(τ≒0)).

[0040] In this embodiment, the TRS method of near-infrared spectroscopy (NIRS) is used as an example of a method for measuring the internal information of object 12. In the TRS method, the internal information of object 12 is obtained from the time-resolved waveform data of the detected light Lb. According to the TRS method, the optical path length inside object 12 can be selected by selecting the time component of the detected light Lb in the time-resolved waveform, and the internal information of object 12 can be measured with high accuracy.

[0041] When the TRS method is used, the light emission unit 3 emits pulsed light as irradiation light La toward the object 12. The pulsed irradiation light La has a time width short enough to measure the internal information of the object 12, for example, a time width of 1 nanosecond or less. If other measurement methods such as the CW method, SRS method, PMS method, SFDI method, DCS method, SCOS method, or SS OCT method are used as the method for measuring the internal information of the object 12, the light emission unit 3 may emit continuous light, intensity-modulated light, structured light, or wavelength-modulated light toward the object 12 as irradiation light La.

[0042] The wavelength range of the irradiated light La is, for example, from the visible light wavelength range to the near-infrared region. The wavelength range of the irradiated light La may be a first wavelength range including, for example, 689 nm, 732 nm, 762 nm, 782 nm, 803 nm, and 834 nm, or a second wavelength range including, for example, 762 nm, 801 nm, 836 nm, 908 nm, 934 nm, and 975 nm. If the wavelength range of the irradiated light La is in the near-infrared region, the upper limit of the wavelength range of the irradiated light La may be, for example, 1800 nm, excluding the absorption band of water.

[0043] The irradiation light La emitted from the light emitting unit 3 in the vertical direction D2 enters the bottom surface 10b of the container through the gap G between the pair of belts 212. The irradiation light La that has entered the bottom surface 10b of the container passes through the container 10 while being scattered and enters the object 12. Among the irradiation light La that has entered the object 12, the reflected light that has been scattered and reflected inside the object 12 is emitted from the object 12 in the vertical direction D2 as the detection light Lb. That is, the detection light Lb is the reflected light that has been reflected by the object 12 among the irradiation light La that has irradiated the object 12. It can also be said that the detection light Lb is a part of the scattered light scattered by the object 12.

[0044] The detection light Lb emitted from the object 12 in the vertical direction D2 and transmitted through the container 10 enters the light detection unit 4. Thus, the container 10 and the object 12 are arranged on the optical path of the irradiation light La from the light emitting unit 3 and on the optical path of the detection light Lb towards the light detection unit 4. That is, the container 10 and the object 12 are arranged on the optical path between the light emitting unit 3 and the light detection unit 4.

[0045] The light detection unit 4 detects the light intensity of the incident detection light Lb and generates an electrical detection signal φ2 indicating the light intensity information (detection result) of the detection light Lb. The light detection unit 4 includes, for example, a semiconductor light receiving element such as a photodiode having a light receiving sensitivity in a wavelength range including the center wavelength of the detection light Lb, a photomultiplier tube, a CCD camera, or a CMOS camera. The light detection unit 4 may further include a preamplifier unit that integrates and amplifies the photocurrent output from the semiconductor light receiving element, the photomultiplier tube, the CCD camera, or the CMOS camera. The light detection unit 4 provides the detection signal φ2 to the processing unit 5.

[0046] As shown in FIG. 1, the processing unit 5 is communicably connected to the light emitting unit 3 and the light detection unit 4. The processing unit 5 receives a detection signal φ2 from the light detection unit 4. Based on the detection signal φ2, the processing unit 5 estimates a coagulation parameter indicating the degree of coagulation of the object 12. The coagulation parameter is a parameter serving as an index for evaluating the degree of coagulation of the object 12. The coagulation parameter includes, for example, at least one of the viscosity [Pa·S], water retention rate [%], and solid content concentration [%] of the object 12. The coagulation parameter is not limited to these parameters, and may include other parameters as long as it is a parameter serving as an index for evaluating the degree of coagulation of the object 12. The processing unit 5 may estimate one of the viscosity, water retention rate, and solid content concentration as the coagulation parameter, or may estimate any two or all of the viscosity, water retention rate, and solid content concentration as the coagulation parameter.

[0047] As shown in FIG. 4, physically, the processing unit 5 includes hardware such as one or more processors 500, a main storage device 502, an auxiliary storage device 503, an input device 504, an output device 505, and a communication device 506. The processing unit 5 is one or more computers constituted by these hardware and software such as programs.

[0048] As shown in FIG. 5, functionally, the processing unit 5 includes an optical parameter calculation unit 51, a coagulation parameter estimation unit 52, and a storage unit 53. Each functional component of the processing unit 5 is realized by a program being executed on the hardware of the above-described computer.

[0049] The optical parameter calculation unit 51 acquires the detection signal φ2 from the photodetector 4. The optical parameter calculation unit 51 calculates the optical parameters of the object 12 using the light intensity information of the detected light Lb indicated by the detection signal φ2. The optical parameters include, for example, the equivalent scattering coefficient, absorption coefficient, average optical path length, counting rate, and the nth moment of the time response waveform. In the TRS method, the equivalent scattering coefficient and absorption coefficient are calculated, for example, by fitting the time response characteristics based on light diffusion theory to match the time response characteristics of the detected light Lb. The average optical path length is calculated from the time difference between the irradiated light La and the detected light Lb, and the propagation speed of light inside the object 12. The light intensity is calculated by counting the detection signal φ2 from the photodetector 4. The counting rate is calculated by converting the light intensity to a value per unit time. The light intensity is the 0th moment of the time response waveform, and the average optical path length is the 1st moment of the time response waveform. Therefore, nth moment information can also be treated as an optical parameter. The optical parameter calculation unit 51 passes the optical parameter information φ21, which indicates the optical parameters calculated in this manner, to the solidification parameter estimation unit 52.

[0050] The memory unit 53 stores correlation information φ22 for estimating the solidification parameters of object 12 from optical parameters. Correlation information φ22 is information showing the correlation between the optical parameters calculated by the optical parameter calculation unit 51 and the solidification parameters indicating the degree of solidification of object 12. The data format of correlation information φ22 may be a graph, a relational expression, or a data table, or any other data format.

[0051] The correlation between optical parameters and solidification parameters will be explained in detail. The inventors have diligently studied methods for inspecting the quality of object 12 using optical methods and have found a significant correlation between optical parameters and solidification parameters. To conduct an experiment to confirm the correlation between optical parameters and solidification parameters, the inventors prepared samples No. 1 to No. 10 shown in Figure 6. Samples No. 1 to No. 10 are all the same type of filled tofu, but have different amounts of coagulant (g / L). Therefore, as shown in Figures 7(a) to 7(c), the solidification parameters (i.e., viscosity, water retention rate, and solid content concentration) indicating the degree of solidification of samples No. 1 to No. 10 are all different.

[0052] The inventors used samples No. 1 to No. 10 to confirm the correlation between optical parameters and solidification parameters under the following experimental conditions. (Experimental conditions) (a) Distance d from the light emission unit 3 and the light detection unit 4 to the bottom surface 10b of the container: 1 cm, 2 cm, 3 cm (b) Wavelength of the irradiated light La: First wavelength region including 689 nm, 732 nm, 762 nm, 782 nm, 803 nm, or 834 nm, or second wavelength region including 762 nm, 801 nm, 836 nm, 908 nm, 934 nm, or 975 nm (c) Measurement method: TRS method (d) Optical parameters: Equivalent scattering coefficient, average optical path length, light intensity, count rate (e) Solidification parameters: Viscosity, water retention rate, solid content concentration Specifically, first, the inventors irradiated the object 12 with irradiated light La of the wavelengths specified in (b) above while maintaining the distance d specified in (a) above. The inventors then calculated the optical parameters (d) obtained by the measurement method (c) above by detecting the detection light Lb emitted in conjunction with the irradiation of the irradiation light La. Subsequently, the inventors calculated the correlation coefficient between the optical parameters (d) above and the solidification parameters (e) above (see Figures 7(a) to 7(c)).

[0053] The experimental results in Figures 8(a) and 8(b) are data tables showing the correlation coefficient between the equivalent scattering coefficient and the solidification parameter. The experimental results in Figures 9(a) and 9(b) are data tables showing the correlation coefficient between the average optical path length and the solidification parameter. The experimental results in Figures 10(a) and 10(b) are data tables showing the correlation coefficient between light intensity and the solidification parameter. The experimental results in Figure 11 are data tables showing the correlation coefficient between the counting rate and the solidification parameter. In each figure, correlation coefficients higher than 0.6 and lower than -0.6 are hatched. Correlation coefficients higher than 0.8 and lower than -0.8 are shown in bold.

[0054] As shown in Figures 8(a) and 8(b), a positive correlation can be seen between the equivalent scattering coefficient and the solidification parameter. Graph G10 shown in Figure 12 is a graph showing the correlation between the equivalent scattering coefficient and viscosity obtained when the object 12 is irradiated with light La at a wavelength of 801 nm, as shown in the experimental results of Figure 8(b). Graph G10 is an approximation line represented by an approximation formula that shows the correlation between the equivalent scattering coefficient and viscosity. If the equivalent scattering coefficient is represented by x and viscosity by y, the approximation formula that shows graph G10 can be expressed as, for example, y = 1.31x - 31.84. From this graph G10, it is clear that there is a positive correlation between the equivalent scattering coefficient and viscosity. As shown in Figures 8(a) and 8(b), there is a similar positive correlation between the equivalent scattering coefficient and other solidification parameters (i.e., water retention and solid content concentration).

[0055] As shown in Figures 9(a) and 9(b), a positive correlation can be seen between the average optical path length and the solidification parameter. Therefore, it can be said that as viscosity, water retention, and solid content concentration increase, the equivalent scattering coefficient tends to increase and the average optical path length tends to lengthen. As shown in Figures 10(a) and 10(b), a negative correlation can be seen between light intensity and the solidification parameter. As shown in Figure 11, a negative correlation can be seen between the counting rate and the solidification parameter. Therefore, it can be said that as viscosity, water retention, and solid content concentration increase, the light intensity and counting rate tend to decrease.

[0056] Thus, it can be seen that all optical parameters have a significant correlation with the coagulation parameters. Therefore, if optical parameters can be obtained, coagulation parameters can be estimated. The storage unit 53 shown in Figure 5 pre-stores correlation information φ22 that shows the correlation between optical parameters and coagulation parameters. The correlation information φ22 may include, for example, the data tables shown in Figures 8 to 11, the graph G10 shown in Figure 12, or an approximation formula for obtaining the graph G10. The correlation information φ22 may include data tables, graphs, or approximation formulas that show the correlation of all combinations of optical parameters and coagulation parameters. The storage unit 53 passes the correlation information φ22 to the coagulation parameter estimation unit 52.

[0057] The solidification parameter estimation unit 52 shown in Figure 5 estimates solidification parameters indicating the degree of solidification of object 12 using light intensity information of the detected light Lb indicated by the detection signal φ2 and correlation information φ22 showing the relationship between optical parameters and solidification parameters. Specifically, the solidification parameter estimation unit 52 converts the optical parameters calculated by the optical parameter calculation unit 51 into solidification parameters by referring to correlation information φ22 in which optical parameters and solidification parameters are pre-associated. For example, the solidification parameter estimation unit 52 converts the equivalent scattering coefficient into viscosity, water retention rate, and solid content concentration by referring to graph G10 showing the relationship between the equivalent scattering coefficient and solidification parameters. The solidification parameter estimation unit 52 similarly converts other optical parameters (i.e., average optical path length, light intensity, and count rate) into viscosity, water retention rate, and solid content concentration. The solidification parameter estimation unit 52 provides the solidification parameter information φ3 indicating the estimated solidification parameters to the sorting unit 6.

[0058] The sorting unit 6 shown in Figure 1 is connected to the processing unit 5 in a communication manner. The sorting unit 6 may be a separate computer from the processing unit 5, or it may be the same computer as the processing unit 5. The sorting unit 6 determines the degree of solidification of the object 12 by referring to the solidification parameters indicated by the solidification parameter information φ3. Specifically, if the solidification parameters are within the standard (within the acceptable range), the sorting unit 6 determines that the degree of solidification of the object 12 is normal. In this case, the sorting unit 6 outputs an instruction signal φ4 to the arm unit 7 instructing it to leave the object 12 on the production line. If the solidification parameters are outside the standard (outside the acceptable range), the sorting unit 6 determines that the degree of solidification of the object 12 is abnormal. In this case, the sorting unit 6 outputs an instruction signal φ5 to the arm unit 7 instructing it to remove the object 12 from the production line.

[0059] When the arm unit 7 receives an instruction signal φ4 from the sorting unit 6, it allows the object T to pass through the production line as is. When the arm unit 7 receives an instruction signal φ5 from the sorting unit 6, it removes the object T from the production line. Therefore, only object T with a normal degree of solidification is supplied to the production line.

[0060] Referring to Figure 13, an example of an inspection method performed using the inspection device 1 described above will be explained.

[0061] First, the light emitting unit 3 of the inspection device 1 irradiates the object T being transported by the belt conveyor 21 with irradiation light La (step S10). Specifically, the light emitting unit 3 irradiates the container bottom surface 10b with irradiation light La in the vertical direction D2. The irradiation light La that enters the container bottom surface 10b diffuses and passes through the container 10, entering the object 12 inside the container 10. Of the irradiation light La that enters the object 12, the reflected light that is reflected by the object 12 is emitted from the object 12 as detection light Lb.

[0062] Next, the photodetector 4 of the inspection device 1 detects the detection light Lb emitted from the object 12 (step S11). Specifically, the photodetector 4 detects the light intensity of the detection light Lb emitted from the object 12 in the vertical direction D2 and transmitted through the container 10, and generates an electrical detection signal φ2 indicating the light intensity information of the detection light Lb. The photodetector 4 provides the detection signal φ2 to the processing unit 5.

[0063] Next, the optical parameter calculation unit 51 of the processing unit 5 calculates the optical parameters of the object 12 using the light intensity information of the detected light Lb indicated by the detection signal φ2 (step S12). The optical parameters include, for example, the equivalent scattering coefficient, average optical path length, light intensity, and counting rate. The optical parameter calculation unit 51 passes the optical parameter information φ21 indicating the calculated optical parameters to the solidification parameter estimation unit 52.

[0064] Next, the solidification parameter estimation unit 52 of the processing unit 5 estimates solidification parameters indicating the degree of solidification of the object 12 using the light intensity information of the detected light Lb indicated by the detection signal φ2 and the correlation information φ22 indicating the relationship between the optical parameters and the solidification parameters (step S13). Specifically, the solidification parameter estimation unit 52 converts the optical parameters calculated by the optical parameter calculation unit 51 into solidification parameters by referring to the correlation information φ22. The solidification parameters include the viscosity, water retention rate, and solid content concentration of the object 12. The solidification parameter estimation unit 52 provides the solidification parameter information φ3 indicating the estimated solidification parameters to the sorting unit 6.

[0065] Next, the sorting unit 6 determines whether the solidification parameters are within the specifications (within the acceptable range) (step S14). If the sorting unit 6 determines that the solidification parameters are within the specifications (Yes in step S14), it determines that the degree of solidification of object 12 is normal and supplies the object T to the production line as is (step S15). If the sorting unit 6 determines that the solidification parameters are outside the specifications (outside the acceptable range) (No in step S14), it determines that the degree of solidification of object 12 is abnormal and removes the object T from the production line (step S16).

[0066] The effects obtained by the inspection apparatus 1 and inspection method of this embodiment, as described above, will now be explained.

[0067] The inspection device 1 of this embodiment utilizes the correlation between optical parameters and solidification parameters to estimate solidification parameters, which indicate the degree of solidification of a gel-like or sol-like object 12, based on the optical parameters obtained from the detection result of the detected light Lb. In this case, unlike when the degree of solidification of the object 12 is evaluated based on the operator's intuition and experience, the degree of solidification of the object 12 can be evaluated non-destructively and objectively, making it possible to efficiently inspect the quality of the object T. When inspecting the quality of the object T using the correlation between optical parameters and solidification parameters, as in the inspection device 1 of this embodiment, it is possible to accurately inspect the quality of the object T with a simple configuration without using a vibration device to obtain a change in the speckle pattern, unlike when inspecting the quality of the object using a change in the state of the speckle pattern, as in Patent Document 1. When the container 10 containing the object 12 is made of a material with light scattering properties, as in the inspection device 1 of this embodiment, the irradiated light La and detected light Lb can be diffused in the container 10 as they pass through the container 10, allowing them to reach the object 12 more reliably. This allows for more reliable detection of the detection light Lb containing internal information of the object 12, enabling a non-destructive and accurate evaluation of the degree of solidification of the object 12 based on the detection result of the detection light Lb.

[0068] As in this embodiment, the light emission unit 3 may emit pulsed light as irradiation light La toward the object 12. In this case, the optical parameters, which are internal information of the object T, can be accurately determined by the TRS method, which utilizes the time-resolved waveform of the detection light Lb. When using the TRS method which assumes pulsed light, due to its measurement principle, even when the irradiation light La is irradiated onto the object 12 through the container 10, it has the advantage of being less affected by the container 10 and making it easier to extract internal information of the object 12 inside the container 10. When pulsed light is used as irradiation light La in this way, there is the advantage that optical parameters with a high correlation to solidification parameters can be calculated, and even when the light intensity of the detection light Lb is small, the optical parameters can be accurately calculated with the light emission unit 3 and the light detection unit 4 at a certain distance from the object T. Therefore, in this embodiment, the optical parameters, which are internal information of the object 12, can be accurately calculated using the TRS method. This makes it possible to accurately estimate solidification parameters based on optical parameters.

[0069] As in this embodiment, the object T may include a film 11 that closes the container opening A through which the object 12 is exposed. The film 11 is made of a material that can transmit irradiation light La and detection light Lb, and may be made of a material whose light reflectance to irradiation light La and detection light Lb is higher than that of the container 10. Even when the container opening A is closed with the film 11, irradiation light La can be applied to the object 12 through the film 11 or the container 10, and detection light Lb can be detected from the object 12 without removing the film 11. This makes it easy to estimate solidification parameters based on optical parameters obtained from the detection result of detection light Lb.

[0070] As in this embodiment, the light emission unit 3 and the light detection unit 4 may be positioned facing the container 10 and adjacent to each other. In this case, the irradiation light La emitted from the light emission unit 3 passes through the container 10 and irradiates the object 12. Of the irradiation light La irradiated onto the object 12, the reflected light that propagates inside the object 12 and is reflected off the object 12 is emitted from the object 12 as detection light Lb, passes through the container 10 and is detected by the light detection unit 4. Even when performing reflective measurement through the container in this way, the solidification parameters indicating the solidification state of the object 12 can be accurately estimated based on the optical parameters obtained from the detection result of the detection light Lb.

[0071] As in this embodiment, the light emission unit 3 and the light detection unit 4 may be located at a distance d from the object T. Even when the light emission unit 3 and the light detection unit 4 are located at a distance from the object T, the optical parameters obtained from the detection result of the detected light Lb can be calculated with high accuracy, and the solidification parameters can be estimated with high accuracy based on the optical parameters. In this embodiment, compared to an embodiment in which contact between the light emission unit 3 and the light detection unit 4 and the object T is assumed, the irradiation of the light La onto the object T flowing through the manufacturing line and the detection of the detected light Lb can be easily performed.

[0072] As in this embodiment, the light emission unit 3 and the light detection unit 4 may be positioned facing the bottom surface 10b of the container. During the manufacturing process of the object 12, when the object 12 is solidified inside the container 10, bubbles may be generated inside the container 10. Such bubbles can change the direction of light propagation in an unintended direction, which can reduce the accuracy of the detection result of the detected light Lb. However, such bubbles tend to float upward inside the container 10 and are unlikely to form near the bottom surface 10b of the container. In this embodiment, irradiation of the object 12 with irradiation light La and detection of the detected light Lb from the object 12 can be performed through the bottom surface 10b of the container, where bubbles are unlikely to form. This reduces the risk of reduced accuracy of the detection result of the detected light Lb due to bubble formation. As a result, the solidification parameters can be accurately estimated based on the optical parameters obtained from the detection result of the detected light Lb.

[0073] As in this embodiment, the processing unit 5 may include an optical parameter calculation unit 51 that calculates optical parameters using a detection signal φ2, a storage unit 53 that stores correlation information φ22 showing the correlation between optical parameters and solidification parameters, and a solidification parameter estimation unit 52 that converts optical parameters into solidification parameters using the correlation information φ22. In this case, the solidification parameters based on optical parameters can be easily estimated using the pre-stored correlation information φ22.

[0074] As in this embodiment, the optical parameters may include at least one of the equivalent scattering coefficient, average optical path length, light intensity, counting rate, and the nth moment of the time response waveform. Based on such optical parameters, the solidification parameters can be estimated with high accuracy.

[0075] As in this embodiment, the solidification parameters may include at least one of viscosity, solid content concentration, and water retention rate. Using such solidification parameters as indicators, the degree of solidification of the object 12 can be evaluated with high accuracy.

[0076] The following describes some variations of the first embodiment.

[0077] <Modification 1 of the First Embodiment> In the inspection apparatus 1A shown in Figures 14 and 15, the belt conveyor 21A of the transport section 2A has a partition member 213 in addition to a pair of rollers 211 and a pair of belts 212. The partition member 213 is, for example, plate-shaped with the left-right direction D3 as the thickness direction. The partition member 213 extends between the pair of rollers 211 along the transport direction D1 so as to partition the space G between the pair of belts 212 between the light emitting section 3 and the light detection section 4. As shown in Figure 15, the partition member 213 positioned between the light emitting section 3 and the light detection section 4 is in contact with the container bottom surface 10b in the vertical direction D2. The partition member 213 includes an upper surface 213a that is in contact with the container bottom surface 10b. The upper surface 213a is positioned at the same location as the belt surface 212a in the vertical direction D2.

[0078] The length of the partition member 213 in the vertical direction D2 is longer than the distance d between the container bottom surface 10b and the light emission unit 3 and the light detection unit 4. The partition member 213 is made of a material that shields or absorbs the irradiation light La from the light emission unit 3. Therefore, the optical path of the irradiation light La between the light emission unit 3 and the object T and the optical path of the detected light Lb between the light detection unit 4 and the object T are separated by the partition member 213. As a result, the inspection device 1A can reduce the risk that a portion of the irradiation light La from the light emission unit 3 will become stray light and enter the light detection unit 4. This allows for accurate calculation of optical parameters based on the detection result of the detected light Lb, and thus allows for accurate estimation of solidification parameters.

[0079] <Modification 2 of the First Embodiment> In the inspection apparatus 1B shown in Figures 16 and 17, the belt conveyor 21B of the transport section 2B has multiple belts 212A instead of a pair of belts 212. The multiple belts 212A are round belts formed in an endless shape from, for example, silicone rubber. The multiple belts 212A are arranged, for example, at equal intervals along the left-right direction D3 and are stretched over a pair of rollers 211. The multiple belts 212A form a loading section on which the object T is placed and transported.

[0080] As shown in Figure 17, the light emission unit 3 and the light detection unit 4 are each positioned between two adjacent belts 212A. The light detection unit 4 is positioned adjacent to the light emission unit 3, with one belt 212A in between. The belt 212A between the light emission unit 3 and the light detection unit 4 separates the optical path of the irradiation light La between the light emission unit 3 and the object T from the optical path of the detection light Lb between the light detection unit 4 and the object T, similar to the partition member 213 described above. Therefore, in the inspection device 1B, the risk of a portion of the irradiation light La from the light emission unit 3 becoming stray light and entering the light detection unit 4 can be reduced. As a result, optical parameters can be calculated accurately based on the detection result of the detection light Lb, and thus solidification parameters can be estimated accurately.

[0081] <Modification 3 of the First Embodiment> In the inspection apparatus 1C shown in Figure 18, the light emission unit 3 and the light detection unit 4 are in contact with the bottom surface 10b of the container. In this case, the irradiation light La emitted from the light emission unit 3 directly enters the bottom surface 10b of the container without passing through air. The detection light Lb emitted from the object 12 and transmitted through the container 10 directly enters the light detection unit 4 without passing through air. Therefore, even in the inspection apparatus 1C, the risk of a portion of the irradiation light La from the light emission unit 3 becoming stray light and entering the light detection unit 4 can be reduced. As a result, optical parameters can be calculated accurately based on the detection result of the detection light Lb, and solidification parameters can be estimated accurately based on the optical parameters. The light emission unit 3 and the light detection unit 4 may be in contact with the side P2 of the container 10, or they may be in contact with the film 11.

[0082] <Modification 4 of the First Embodiment> In the inspection device 1D shown in Figure 19, the light emitting unit 3 and the light detection unit 4 are positioned facing the film 11. That is, the light emitting unit 3 and the light detection unit 4 face the object 12 in the vertical direction D2 via the film 11. The light emitting unit 3 and the light detection unit 4 may be, for example, separated from the film 11 but in contact with the film 11. In the inspection device 1D, the irradiation light La emitted from the light emitting unit 3 passes through the film 11 and enters the object 12. The detection light Lb emitted from the object 12 passes through the film 11 and enters the light detection unit 4.

[0083] Figure 20(a) is a graph showing the instrument function waveform G11 and the time response waveform G12 of the detected light Lb obtained when using the inspection device 1D. In the time region earlier than the range R shown in Figure 20(a), it is considered that waveform distortion occurs in the time response waveform G12 due to the propagation of light on the film 11. Therefore, the equivalent scattering coefficient is calculated by fitting only to the time region R. The experimental results in Figure 20(b) are a data table showing the correlation between the equivalent scattering coefficient calculated from the range R in Figure 20(a) and the solidification parameter. The experimental conditions in Figures 20(a) and (b) are the same as the experimental conditions of the first embodiment described above.

[0084] As shown in Figure 20(a), when waveform distortion occurs due to light propagation on the film 11, analysis in the time domain indicated by range R reveals a positive correlation between the equivalent scattering coefficient and the solidification parameter, as shown in Figure 20(b). As shown in Figure 21(a), a positive correlation is also found between the average optical path length and the solidification parameter. As shown in Figure 21(b), there is a negative correlation between light intensity and the solidification parameter, and as shown in Figure 22, there is a negative correlation between the counting rate and the solidification parameter. Therefore, even when irradiation with irradiation light La and detection light Lb are performed through the film 11, as in the inspection device 1D, the solidification parameter can be estimated by utilizing the correlation between the optical parameter and the solidification parameter, and the degree of solidification of the object 12 can be determined from the solidification parameter. When the light emission unit 3 or the light detection unit 4 is in contact with the film 11, it is appropriate to fix the pressing pressure of the light emission unit 3 or the light detection unit 4 against the film 11. This reduces the risk that the detection result of the detected light Lb may fluctuate due to variations in the pressing pressure of the light emission unit 3 or the light detection unit 4 against the film 11.

[0085] <Modification 5 of the First Embodiment> In the inspection apparatus 1E shown in Figure 23, the object TA does not have a film 11, and the object 12 is exposed from the container opening A. The light emitting unit 3 and the light detection unit 4 are positioned to directly face the object 12 exposed from the container opening A. In this case, the irradiation light La emitted from the light emitting unit 3 is directly incident on the object 12. The detection light Lb emitted from the object 12 is directly incident on the light detection unit 4. The light emitting unit 3 and the light detection unit 4 may be in direct contact with the object 12 exposed from the container opening A.

[0086] The experimental results in Figures 24(a) and 24(b) are graphs showing the correlation between the equivalent scattering coefficient and the solidification parameter when using the inspection device 1E. As shown in Figures 24(a) and 24(b), it can be seen that there is a positive correlation between the equivalent scattering coefficient and the solidification parameter. There is a positive correlation between the average optical path length and the solidification parameter, and negative correlations between light intensity and the solidification parameter, and between the counting rate and the solidification parameter. Therefore, even when the object 12 is directly irradiated with irradiation light La, as in the inspection device 1E, the solidification parameter can be estimated by utilizing the correlation between the optical parameter and the solidification parameter, and the degree of solidification of the object 12 can be determined from the solidification parameter.

[0087] <Second Embodiment> The inspection device 101 shown in Figure 25 differs from the inspection device 1 of the first embodiment in that the light emission unit 3 and the light detection unit 4 are arranged so that transmission-type measurement is performed on the object 12. The other components of the inspection device 101 are the same as those of the inspection device 1 of the first embodiment.

[0088] As shown in Figures 26 and 27, the light-emitting unit 3 and the light-detecting unit 4 are positioned facing each other with the object T in between. In other words, the light-detecting unit 4 is positioned on the opposite side of the object T from the light-emitting unit 3. The light-emitting unit 3 is positioned facing the film 11 in the vertical direction D2. The light-detecting unit 4 is positioned facing the container bottom surface 10b in the vertical direction D2.

[0089] The light detection unit 4 is positioned, for example, on the optical axis of the light emission unit 3. That is, the optical axis of the light detection unit 4 coincides with the optical axis of the light emission unit 3. The optical axis of the light detection unit 4 may be positioned so as to be offset from the optical axis of the light emission unit 3. The relative positions of the light emission unit 3 and the light detection unit 4 may be reversed. That is, the light emission unit 3 may be positioned facing the container bottom surface 10b in the vertical direction D2, and the light detection unit 4 may be positioned facing the film 11 in the vertical direction D2.

[0090] As shown in Figure 27, the light-emitting unit 3 is, for example, separated from the film 11 by a predetermined distance d1 in the vertical direction D2. The light-detecting unit 4 is, for example, separated from the container bottom surface 10b by a predetermined distance d2 in the vertical direction D2. Distance d2 is, for example, the same as distance d1. When distance d2 is the same as distance d1, distances d1 and d2 are, for example, 0 cm or more and 4 cm or less. Distance d2 may be different from distance d1.

[0091] The light emission unit 3 irradiates the object 12 with irradiation light La in the vertical direction D2 through the film 11. The irradiation light La incident on the object 12 diffuses through the inside of the object 12 and passes through the object 12 and the container 10. Of the irradiation light La incident on the object 12, the transmitted light that has passed through the object 12 and the container 10 is emitted from the object 12 as detection light Lb and detected by the light detection unit 4.

[0092] As shown in Figure 28(a), the light-emitting unit 3 may be away from the film 11, while the light-detecting unit 4 may be in contact with the bottom surface 10b of the container. Conversely, as shown in Figure 28(b), the light-detecting unit 4 may be away from the bottom surface 10b of the container, while the light-emitting unit 3 may be in contact with the film 11. In this way, only one of the light-emitting unit 3 or the light-detecting unit 4 may be in contact with the object T. As shown in Figure 28(c), the light-emitting unit 3 may be in contact with the film 11, while the light-detecting unit 4 is in contact with the bottom surface 10b of the container. In other words, both the light-emitting unit 3 and the light-detecting unit 4 may be in contact with the object T. In Figures 28(a) to 28(c), the optical axis of the light-emitting unit 3 does not necessarily have to coincide with the optical axis of the light-detecting unit 4, and may be positioned offset from the optical axis of the light-detecting unit 4.

[0093] In Figures 28(a) to 28(c), the relative positions of the light-emitting unit 3 and the light-detecting unit 4 may be reversed. Specifically, the light-emitting unit 3 may be in contact with the bottom surface 10b of the container while the light-detecting unit 4 is away from the film 11. The light-emitting unit 3 may be away from the bottom surface 10b of the container while the light-detecting unit 4 is in contact with the film 11. The light-emitting unit 3 may be in contact with the bottom surface 10b of the container, while the light-detecting unit 4 is in contact with the film 11. When the light-emitting unit 3 or the light-detecting unit 4 is in contact with the film 11, it is appropriate to fix the pressing pressure of the light-emitting unit 3 or the light-detecting unit 4 against the film 11. This reduces the risk that the detection result of the detected light Lb will fluctuate due to fluctuations in the pressing pressure of the light-emitting unit 3 or the light-detecting unit 4 against the film 11.

[0094] The arrangement of the light-emitting unit 3 and the light-detecting unit 4 is not limited to positions where they face each other in the vertical direction D2 with the object T in between. For example, as shown in Figure 29(a), the light-emitting unit 3 and the light-detecting unit 4 may be arranged so that they face each other in the left-right direction D3 with the object T in between. In this case, each of the light-emitting unit 3 and the light-detecting unit 4 is positioned so that they face the side P2 of the container 10 in the left-right direction D3. Both the light-emitting unit 3 and the light-detecting unit 4 may be in contact with the side P2 of the container 10 (see Figure 29(a)). Only the light-emitting unit 3 may be in contact with the side P2 of the container 10 (see Figure 29(b)). Only the light-detecting unit 4 may be in contact with the side P2 of the container 10 (see Figure 29(c)). In Figures 29(a) to 29(c), the arrangement of the light-emitting unit 3 and the light-detecting unit 4 may also be reversed. The optical axes of the light-emitting unit 3 and the light-detecting unit 4 may coincide with each other. The optical axes of the light-emitting unit 3 and the light-detecting unit 4 may be offset from each other.

[0095] The experimental results in Figures 30(a), 30(b), 31(a), 31(b), and 32 are data tables showing the correlation coefficients between optical parameters and solidification parameters obtained when using the inspection device 101. However, these experimental results were obtained under experimental conditions in which (a) of the (experimental conditions) of the above-described embodiment was replaced with (aa) below. In other words, the experimental conditions of this embodiment include (aa) below and (b) to (e) above. (Experimental conditions) (aa) Contact state of the light emitting unit 3 and the light detecting unit 4 with respect to the object T: double-sided contact, single-sided contact, non-contact In (aa) above, double-sided contact means a state in which both the light emitting unit 3 and the light detecting unit 4 are in contact with the object T, specifically, a state in which the light emitting unit 3 is in contact with the film 11 and the light detecting unit 4 is in contact with the bottom surface 10b of the container (see Figure 28(c)). One-sided contact means a state in which only one of the light-emitting unit 3 and the light-detecting unit 4 is in contact with the object T, specifically a state in which the light-emitting unit 3 is away from the film 11 while the light-detecting unit 4 is in contact with the bottom surface 10b of the container (see Figure 28(a)). Non-contact means a state in which neither the light-emitting unit 3 nor the light-detecting unit 4 is in contact with the object T, specifically a state in which the light-emitting unit 3 is away from the film 11 and the light-detecting unit 4 is away from the bottom surface 10b of the container (see Figure 27).

[0096] As shown in Figures 30(a) and 30(b), a positive correlation can be seen between the equivalent scattering coefficient and the solidification parameter. As shown in Figure 31(a), a positive correlation can also be seen between the average optical path length and the solidification parameter. As shown in Figures 31(b) and 32, a negative correlation can be seen between the light intensity and the solidification parameter, and also between the counting rate and the solidification parameter. Therefore, even when performing transmission measurement, such as with the inspection device 101, which detects the detection light Lb that has passed through the object 12 and the container 10 from the irradiated light La, the solidification parameter can be estimated by utilizing the correlation between the optical parameter and the solidification parameter, and the degree of solidification of the object 12 can be determined from the solidification parameter.

[0097] The following describes some variations of the second embodiment.

[0098] <Modification 1 of the Second Embodiment> In the inspection device 101A shown in Figures 33 and 34, the light emitting unit 3 is positioned facing the bottom surface 10b of the container, and the light detection unit 4 is positioned facing the film 11. In the inspection device 101A, the belt conveyor 121A of the transport unit 102A has a partition member 214 in addition to a pair of rollers 211 and a pair of belts 212.

[0099] The partition member 214 is, for example, plate-shaped with its thickness in the vertical direction D2. The partition member 214 is positioned inside the pair of belts 212 and extends along the transport direction D1 and the left-right direction D3. The partition member 214 is positioned between the light emitting unit 3 and the belt 212 on which the object T is placed, and is positioned away from the light emitting unit 3 and the belt 212, respectively. The partition member 214 is made of a material that shields or absorbs the irradiation light La emitted from the light emitting unit 3.

[0100] The partition member 214 has an opening 214a that allows the irradiation light La emitted from the light emission unit 3 to pass through. The opening 214a is formed in a position that overlaps with the gap G between the pair of belts 212 in the vertical direction D2. Therefore, the irradiation light La emitted from the light emission unit 3 passes through the opening 214a of the partition member 214 and the gap G between the pair of belts 212, and is irradiated onto the bottom surface 10b of the container.

[0101] The partition member 214 shields or absorbs the component of the irradiated light La that is reflected at the bottom surface 10b of the container and returns to the light emission unit 3. Therefore, the inspection device 101A can reduce the risk that a portion of the irradiated light La is reflected at the bottom surface 10b of the container and returns to the light emission unit 3. As a result, optical parameters can be calculated with high accuracy based on the detection result of the detection light Lb emitted from the object 12 in conjunction with the irradiated light La, and thus the solidification parameters based on the optical parameters can be estimated with high accuracy.

[0102] <Modification 2 of the Second Embodiment> In the inspection device 101B shown in Figure 35(a), the light emitting unit 3 is positioned facing the bottom surface 10b of the container, and the light detection unit 4 is positioned facing the film 11. In the inspection device 101B, the container 10 is placed in the gap G between a pair of belts 212, and the edge P3 of the container 10 is supported by the pair of belts 212. In other words, in the inspection device 101B, the edge P3 of the container 10 is positioned to catch on the pair of belts 212. In this case, the pair of belts 212 function as partition members that shield or absorb the irradiation light La from the light emitting unit 3. In this case, the risk of a part of the irradiation light La from the light emitting unit 3 becoming stray light, wrapping around the container 10, and entering the light detection unit 4 can be reduced. As a result, optical parameters can be calculated accurately based on the detection result of the detected light Lb, and the solidification parameters based on the optical parameters can be estimated accurately.

[0103] The inspection device 101C shown in Figure 35(b) includes a partition member 215 in addition to the inspection device 101B described above. The partition member 215 is cylindrical in shape and surrounds the photodetector 4. The partition member 215 is made of a material that shields or absorbs light other than the detection light Lb directed toward the photodetector 4. In this case, only the detection light Lb that has passed through the object 12 and the container 10 of the irradiated light La is likely to enter the photodetector 4, thus reducing the risk of other light other than the detection light Lb entering the photodetector 4. As a result, optical parameters can be calculated accurately based on the detection result of the detection light Lb detected by the photodetector 4, and the solidification parameters based on the optical parameters can be estimated accurately. In the inspection devices 101B and 101C, the light emission unit 3 may be in contact with the bottom surface 10b of the container, and the photodetector 4 may be in contact with the film 11. The arrangement of the light emission unit 3 and the photodetector 4 may be reversed. In other words, the light detection unit 4 may be positioned facing the bottom surface 10b of the container, and the light emission unit 3 may be positioned facing the film 11.

[0104] <Modification 3 of the Second Embodiment> In the inspection apparatus 101D shown in Figure 36, the object TA does not have a film 11, and the object 12 is exposed from the container opening A. The light emitting unit 3 is positioned to directly face the object 12 exposed from the container opening A. The light detection unit 4 is positioned to face the bottom surface 10b of the container. In this case, the irradiation light La emitted from the light emitting unit 3 is directly incident on the object 12. Even when the irradiation light La is directly irradiated onto the object 12 in this way, the solidification parameters can be estimated by utilizing the correlation between optical parameters and solidification parameters, and the degree of solidification of the object 12 can be determined from the solidification parameters.

[0105] In the inspection device 101D, the light emitting unit 3 may be in direct contact with the object 12 exposed from the container opening A, or it may be at a distance from the object 12. The light detection unit 4 may be in direct contact with the object 12 exposed from the container opening A, or it may be at a distance from the object 12. The relative positions of the light emitting unit 3 and the light detection unit 4 may be reversed. That is, the light emitting unit 3 may be positioned facing the bottom surface 10b of the container, and the light detection unit 4 may be positioned facing the object 12 exposed from the container opening A.

[0106] <Modification 4 of the Second Embodiment> In the inspection device 101E shown in Figure 37, the light detection unit 4 is positioned facing the bottom surface 10b of the container, and the light emission unit 3 is positioned facing the film 11. In the inspection device 101E, the light emission unit 3 is positioned further from the object T than the light detection unit 4. That is, the distance d3 between the film 11 and the light emission unit 3 is greater than the distance d4 between the bottom surface 10b of the container and the light detection unit 4. Each of the distances d3 and d4 may be, for example, 0 cm or more and 10 cm or less, or 0 cm or more and 20 cm or less. The combination of distances d3 and d4 may be a combination of 5 mm and 10 cm, a combination of 0 cm and 4 cm, or any other combination. By using an optical system including lenses and mirrors, the distances d3 and d4 can also be made infinite. When the focus of the irradiated light La is set to the bottom surface 10b of the container using an optical system, it may be possible to improve the measurement accuracy compared to when an optical system is not used.

[0107] In the inspection device 101E, the light detection unit 4 may be positioned further away from the object T than the light emission unit 3. That is, the distance d4 between the container bottom surface 10b and the light detection unit 4 may be greater than the distance d3 between the film 11 and the light emission unit 3. The light emission unit 3 may be positioned facing the container bottom surface 10b, and the light detection unit 4 may be positioned facing the film 11.

[0108] In previous experiments, a correlation has been confirmed between the solidification parameter of object 12 and the equivalent scattering coefficient of object 12 itself. If a correlation is found between the equivalent scattering coefficient of object 12 itself and the measurement parameters measured via container 10, it is possible to estimate the solidification parameter using the measurement parameters via container 10. In order to confirm that there is a correlation between optical parameters and solidification parameters even when distances d3 and d4 are set to be different from each other, as in the inspection device 101E, the inventors conducted an experiment to calculate the correlation coefficient between optical parameters and the equivalent scattering coefficient of object 12 under the following experimental conditions. (Experimental conditions) (a1) Experimental samples: an experimental sample in which undiluted soy milk is filled into a container 10, an experimental sample in which 80% concentrated soy milk is filled into a container, and an experimental sample in which 60% concentrated soy milk is filled into a container 10. (b1) Combinations of the distance d3 between the film 11 and the light emission unit 3 and the distance d4 between the bottom surface 10b of the container and the light detection unit 4: (d3=0cm, d4=0cm), (d3=1cm, d4=1cm), (d3=4cm, d4=4cm), (d3=4cm, d4=0cm), (d3=5mm, d4=10cm), (d3=10cm, d4=5mm), (d3=0cm, d4=4mm), (d3=5.5cm, d4=5cm) (c1) Wavelength of the irradiated light La: 762nm, 801nm, 836nm, 908nm, 934nm, or 975nm (d1) Measurement method: TRS method (e1) Optical parameters: Equivalent scattering coefficient of the object 12 (soy milk solution) itself, equivalent scattering coefficient measured through the container 10 (measurement parameters) However, the correlation with the coagulation parameters is assumed to be known. (f1) Coagulation parameters: Viscosity, water retention rate, solid content concentration

[0109] Figure 38 is a data table showing the correlation coefficient between the equivalent scattering coefficient via the container 10 and the equivalent scattering coefficient of the object 12. As shown in Figure 38, a positive correlation is observed between the equivalent scattering coefficient via the container 10 and the equivalent scattering coefficient of the object 12, whether the light emitter 3 and the light detector 4 are both in contact with the object T via the container 10, whether the light emitter 3 and the light detector 4 are at the same distance from the object T, or whether the light emitter 3 and the light detector 4 are at different distances from the object T. Therefore, even when the distance d4 is different from the distance d3, as in the inspection device 101E, the solidification parameter can be estimated by utilizing the correlation between the optical parameter and the solidification parameter, and the degree of solidification of the object 12 can be determined from the solidification parameter.

[0110] The inventors have confirmed that there is a correlation between optical parameters and solidification parameters even when the distance d4 between the container bottom surface 10b and the photodetector 4 is set to the maximum of 18 cm in the experimental system, with the light-emitting unit 3 in contact with the film 11 (i.e., d3 = 0 cm). The inventors have also confirmed that there is a correlation between optical parameters and solidification parameters even when the distance d3 between the film 11 and the light-emitting unit 3 is set to 10 cm, with the photodetector 4 in contact with the container bottom surface 10b (i.e., d4 = 0 cm).

[0111] <Third Embodiment> The inspection device 201 shown in Figure 39(a) differs from the inspection device 1 of the first embodiment in that it uses the SRS method instead of the TRS method to determine optical parameters. The inspection device 201 includes, for example, a plurality of (two in one example) light-emitting units 3A and a plurality of (two in one example) light-detecting units 4A. Each of the plurality of light-emitting units 3A has the same configuration as the light-emitting unit 3 described above. Each of the plurality of light-detecting units 4A has the same configuration as the light-detecting unit 4 described above. The plurality of light-emitting units 3A and the plurality of light-detecting units 4A are arranged in a position facing the bottom surface 10b of the container. The plurality of light-emitting units 3A and the plurality of light-detecting units 4A may be in contact with the bottom surface 10b of the container, but may also be separated from the bottom surface 10b of the container. The plurality of light-emitting units 3A and the plurality of light-detecting units 4A may be pre-installed on the belt conveyor 21. In the TRS method as well, it is possible to inspect the uniformity of object 12 by acquiring optical parameters at multiple points using a similar configuration.

[0112] In the inspection device 201, irradiation light La emitted from each of the multiple light emission units 3A is irradiated onto the object 12 through the container bottom surface 10b, and multiple detection light Lb that propagate inside the object 12 and are emitted from the object 12 are detected by each of the multiple photodetectors 4A. The SRS method utilizes the fact that the amount of light detected by the detection light Lb changes depending on the distance between the multiple light emission units 3A and the multiple photodetectors 4A. For example, the inspection device 201 can calculate the equivalent scattering coefficient by fitting the spatial distribution of the multiple detection light Lb detected by the multiple photodetectors 4A to match the spatial response characteristics based on light diffusion theory. Similar to the inspection device 1 of the first embodiment, the inspection device 201 estimates the solidification parameters based on the calculated optical parameters. Therefore, in the inspection device 201, similar to the inspection device 1 of the first embodiment, the solidification parameters can be estimated by utilizing the correlation between the optical parameters and the solidification parameters, and the degree of solidification of the object 12 can be determined from the solidification parameters.

[0113] As shown in Figure 39(b), the inspection device 201A may be positioned facing the film 11. The multiple light-emitting units 3A and multiple light-detecting units 4A may be, for example, in contact with the film 11 but separated from it. As shown in Figure 39(c), the inspection device 201B may have multiple (four in one example) light-emitting units 3B facing the film 11, or multiple (four in one example) light-detecting units 4B facing the bottom surface 10b of the container. Conversely, multiple light-detecting units 4B may be positioned facing the film 11, or multiple light-emitting units 3B may be positioned facing the bottom surface 10b of the container. Even with inspection devices 201A and 201B, the same effects as the inspection device 201 described above can be obtained. The optical parameters may be calculated by detecting the brightness value of the detected light Lb using a camera, or by other methods.

[0114] <Fourth Embodiment> The inspection device 301 shown in Figure 40 differs from the inspection device 1 of the first embodiment in that the object 12A of the object TB is liquid soy milk concentrate or a diluted version of that concentrate. The light emitting unit 3 and the light detection unit 4 are positioned, for example, at a distance d from the bottom surface 10b of the container. The light emitting unit 3 and the light detection unit 4 may, for example, be in contact with the bottom surface 10b of the container.

[0115] In the process of confirming the correlation between optical parameters and solidification parameters, the inventors discovered a correlation between optical parameters and other quality parameters indicating the quality of object 12A. Specifically, the inventors discovered a significant correlation between optical parameters and the concentration of soy milk in object 12A. Figure 41 is a graph showing the correlation between the equivalent scattering coefficient and the concentration of soy milk. Graph G22 in Figure 41 shows the experimental results obtained under the following experimental conditions when irradiation with irradiation light La and detection light Lb were performed through the bottom surface 10b of the container, as shown in the inspection apparatus 301 in Figure 40. (Experimental conditions) (a2) Experimental samples: Experimental samples filled with undiluted soy milk, experimental samples filled with 80% concentration soy milk, experimental samples filled with 60% concentration soy milk (b2) Distance d from the light emitter 3 and light detector 4 to the bottom surface 10b of the container: 2 cm (c2) Wavelength of the irradiated light La: 762 nm (d2) Measurement method: TRS method (e2) Optical parameter: Equivalent scattering coefficient (f2) Quality parameter: Particle density

[0116] Graph G21 in Figure 41 shows the experimental results obtained when the container opening A is covered with the film 11, and irradiation with light La and detection of light Lb are performed through the film 11. Graph G22 in Figure 41 shows the experimental results obtained when the container opening A is covered with the film 11, and irradiation with light La and detection of light Lb are performed through the bottom surface 10b of the container. Graph G23 in Figure 41 shows the experimental results obtained when the film 11 is removed and the object 12A exposed from the container opening A is irradiated with light La and detection of light Lb is performed. Graph G24 in Figure 41 shows the experimental results obtained when the container opening A is covered with the film 11, and irradiation with light La is performed through the film 11, and detection of light Lb is performed through the bottom surface 10b of the container. As shown in graphs G21 to G24, the equivalent scattering coefficient is proportional to the concentration of soy milk, and it can be seen that there is a positive correlation between the equivalent scattering coefficient and the concentration of soy milk. Therefore, the concentration of soy milk can be estimated from the equivalent scattering coefficient.

[0117] Emulsion particles are diffused in the undiluted soy milk, and the concentration of soy milk can be evaluated by the density of emulsion particles (particle concentration). Furthermore, the scattering amplitude (SA), determined from the multi-wavelength equivalent scattering coefficient, can be said to reflect the density of emulsion particles. Therefore, as shown in graph G30 in Figure 42, there is a positive correlation between the scattering amplitude and the concentration of soy milk. Thus, if the concentration of soy milk can be estimated from the equivalent scattering coefficient, it is also possible to estimate the density of emulsion particles (particle concentration). The inventors have also confirmed that there is a correlation between the concentration of soy milk and other optical parameters such as the average optical path length, light intensity, and counting rate. In this way, by utilizing the correlation between optical parameters calculated based on the detected light Lb and the concentration of soy milk, the concentration of soy milk can be estimated, and the quality of the target object TB can be judged from the concentration of soy milk.

[0118] <Fifth Embodiment> The inspection device 401 shown in Figure 43 includes a transport unit 2C having a reversal unit 216 for reversing the object T. The reversal unit 216 is positioned on the trajectory through which the object T flows in the transport unit 2C. The reversal unit 216 has the function of reversing the object T in the vertical direction D2. Specifically, the reversal unit 216 changes the state from one in which the container bottom surface 10b faces the belt surface 212a to one in which the film 11 faces the belt surface 212a. The reversal unit 216 may also change the state from one in which the film 11 faces the belt surface 212a to one in which the container bottom surface 10b faces the belt surface 212a.

[0119] The reversing portion 216 is, for example, a projection that protrudes in the vertical direction D2 relative to the belt surface 212a. The reversing portion 216 extends, for example, along the left-right direction D3 on the belt surface 212a. The height of the reversing portion 216 in the vertical direction D2 from the belt surface 212a is lower than the height of the object T in the vertical direction D2 from the belt surface 212a. The reversing portion 216 is attached, for example, to a part of the conveying portion 2C that fixes the belt 212, and is stationary relative to the belt 212 that moves along the conveying direction D1. In other words, the reversing portion 216 is fixed in the same position without moving along the conveying direction D1.

[0120] The reversing section 216 has a triangular shape that tapers as it moves away from the belt surface 212a in a cross-section along the conveying direction D1 and the vertical direction D2. The reversing section 216 has a pair of sides 216a that face opposite directions in the left-right direction D3. The pair of sides 216a are positioned to face the object T placed on the belt surface 212a in the conveying direction D1. Each side 216a is inclined so that as it moves away from the belt surface 212a in the vertical direction D2, it moves closer to each other in the left-right direction D3.

[0121] The object T being transported in the transport direction D1 comes into contact with the first side surface 216a, which is one of the pair of side surfaces 216a, in the transport direction D1. The object T that has come into contact with the transport direction D1 goes over the reversing section 216. Subsequently, the object T reverses in the vertical direction D2 by riding over the second side surface 216a, which is the other of the pair of side surfaces 216a. After reversing, the film 11 of the object T faces the belt surface 212a.

[0122] In this way, the reversal unit 216 changes the state from one in which the container bottom surface 10b faces the belt surface 212a to one in which the film 11 faces the belt surface 212a. Similarly, the change from one in which the film 11 faces the belt surface 212a to one in which the container bottom surface 10b of the object T faces the belt surface 212a can be achieved by the object T riding over the reversal unit 216.

[0123] After inversion, the bottom surface 10b of the container of the object T faces the light emitting unit 3 and the light detection unit 4. The light emitting unit 3 and the light detection unit 4 are positioned at a predetermined distance D2 in the vertical direction from the belt surface 212a and are adjacent to each other along the transport direction D1. The light emitting unit 3 irradiates the bottom surface 10b of the container of the object T after inversion with irradiation light La. The light detection unit 4 detects the detection light Lb emitted from the bottom surface 10b of the container of the object T in response to the irradiation of irradiation light La. After detection of the detection light Lb, the container may be returned to a state where the bottom surface 10b faces the belt surface 212a, from a state where the film 11 faces the belt surface 212a, using an element corresponding to the inversion unit 216 again.

[0124] Even with the inspection device 401, the same effects as the inspection device 1 of the first embodiment can be obtained. In the inspection device 401, even when the object T is transported with the container bottom surface 10b facing the belt surface 212a, the object T can be automatically inverted by the inversion unit 216 so that the film 11 faces the belt surface 212a. This makes it easy to irradiate the container bottom surface 10b of the object T being transported to the transport unit 2C with irradiation light La, and to detect the detection light Lb from the container bottom surface 10b. By arranging the light emission unit 3 and the light detection unit 4 in a position facing the belt surface 212a in this way, it becomes unnecessary to process the belt 212 for the installation of the light emission unit 3 and the light detection unit 4, so the light emission unit 3 and the light detection unit 4 can be easily installed using the existing belt 212.

[0125] The following describes some variations of the fifth embodiment.

[0126] <Modification 1 of the Fifth Embodiment> The inspection device 401A shown in Figure 44 differs from the inspection device 401 described above in that it has a conveying unit 2D having a reversing unit 216A instead of a conveying unit 2C having a reversing unit 216. The reversing unit 216A includes a roller 216b and a blade 216c. The roller 216b is, for example, a cylindrical member and extends along the left-right direction D3. The roller 216b is positioned lower than the height of the object T from the belt surface 212a. The roller 216b is attached, for example, to a part of the conveying unit 2C that fixes the belt 212, and is stationary relative to the belt 212 that moves along the conveying direction D1. The roller 216b rotates around a rotation axis along the left-right direction D3.

[0127] The blade 216c extends from the roller 216b toward the belt surface 212a along the vertical direction D2. The tip of the blade 216c is, for example, away from the belt surface 212a but may be in contact with the belt surface 212a. The blade 216c rotates around the axis of rotation of the roller 216b as the roller 216b rotates. The blade 216c rotates in the opposite direction to the transport direction D1 in which the object T is transported. Therefore, when the object T is transported to a position where it contacts the blade 216c, the object T is lifted by the rotating blade 216c and placed on the belt surface 212a in an inverted state in the vertical direction D2. In this state, the object T is irradiated with light La onto the bottom surface 10b of the container, and detection light Lb is detected from the bottom surface 10b of the container. Afterward, the object T may be inverted again in the vertical direction D2 using the element corresponding to the inversion section 216A to return it to its original state (i.e., the state in which the container bottom surface 10b faces the belt surface 212a).

[0128] Thus, the reversing unit 216A, like the reversing unit 216 described above, can change the state from one where the container bottom surface 10b faces the belt surface 212a to one where the film 11 faces the belt surface 212a. Similarly, the change from the state where the film 11 faces the belt surface 212a to the state where the container bottom surface 10b faces the belt surface 212a can be achieved by lifting the object T into the reversing unit 216A. Therefore, the same effect as the inspection device 401 can be obtained even with the inspection device 401A.

[0129] <Modification 2 of the Fifth Embodiment> The inspection device 401B shown in Figure 45 differs from the inspection device 401 in that it has a conveying unit 2E having a reversing unit 216B instead of a conveying unit 2C having a reversing unit 216. The reversing unit 216B is the belt 212B of the conveying unit 2E. The belt 212B is twisted so that one side in the left-right direction D3 gradually becomes higher. The posture of the object T placed on the belt surface 212a of such a belt 212B gradually tilts as it moves along the conveying direction D1. As a result, the object T is reversed in the up-down direction D2 after moving a certain distance along the conveying direction D1. Therefore, the same effect as the inspection device 401 can be obtained even with the inspection device 401B.

[0130] <Sixth Embodiment> In the inspection device 501 shown in Figure 46, irradiation light La is emitted onto the side P2 of the object T, and detection light Lb is detected from the side P2. In this case, the light emission unit 3 and the light detection unit 4 are positioned facing the side P2 of the object T in the left-right direction D3. The light emission unit 3 and the light detection unit 4 may be in contact with the side P2 of the object T, or they may be away from the side P2 of the object T. The inspection device 501 includes a transport unit 2F having one belt 212C instead of a transport unit 2 having a pair of belts 212. The belt 212C is not divided in the left-right direction D3, but is formed from a single member.

[0131] In the inspection device 501, irradiation light La is emitted from the light emission unit 3 towards the side P2 of the object T. The reflected light from the object 12, which has passed through the side P2 and entered the object 12, is emitted from the side P2 as detection light Lb and detected by the light detection unit 4. The measurement method for the detection light Lb is, for example, the TRS method, but other measurement methods such as the SRS method may also be used. The inspection device 501 can obtain the same effects as the inspection device 1 of the first embodiment. The inspection device 501 is highly versatile because it can use the existing belt 212C as is without making any changes such as dividing the belt 212C into two.

[0132] The following describes some variations of the sixth embodiment.

[0133] <Modification 1 of the 6th Embodiment> The inspection device 501A shown in Figure 47 includes partition members 33 and 34 in addition to the inspection device 501. The partition member 33 is cylindrical in shape and surrounds the light emitting section 3. The partition member 33 is, for example, in contact with the side P2 of the container 10, but may be separated from the side P2. The partition member 33 is arranged to surround at least the optical path of the irradiated light La between the light emitting section 3 and the side P2 of the container 10. The partition member 33 is made of a material that shields or absorbs light other than the irradiated light La emitted from the light emitting section 3.

[0134] The partition member 34 is cylindrical in shape and surrounds the light detection unit 4. The partition member 34 is in contact with the side P2 of the container 10. The partition member 34 is positioned to at least surround the optical path of the detected light Lb between the light detection unit 4 and the side P2 of the container 10. The partition member 34 is made of a material that shields or absorbs light other than the detected light Lb emitted from the object T.

[0135] The inspection device 501A, equipped with partition members 33 and 34, reduces the risk of a portion of the irradiation light La from the light emission unit 3 becoming stray light and entering the light detection unit 4. As a result, the inspection device 501A can accurately calculate optical parameters based on the detection result of the detected light Lb detected by the light detection unit 4, and thus accurately estimate solidification parameters based on optical parameters.

[0136] <Modification 2 of the 6th Embodiment> The inspection device 501B shown in Figure 48 includes a partition member 35 in addition to the inspection device 501. The partition member 35 is arranged on the belt surface 212a to partition the space between the light emitting unit 3 and the light detection unit 4. The partition member 35 is plate-shaped with the transport direction D1 as its thickness direction. When viewed along the transport direction D1, for example, the partition member 35 has a U-shape that opens onto the belt surface 212a. Objects T transported in the transport direction D1 by the belt 212C pass through the opening of the partition member 35. The partition member 35 may be in contact with the object T or may be separated from the object T.

[0137] The partition member 35 is made of a material that shields or absorbs the irradiation light La from the light emission unit 3. Therefore, the optical path of the irradiation light La between the light emission unit 3 and the object T and the optical path of the detected light Lb between the light detection unit 4 and the object T are separated by the partition member 35. As a result, the inspection device 501B can reduce the risk that a portion of the irradiation light La from the light emission unit 3 will become stray light and enter the light detection unit 4. This allows for accurate calculation of optical parameters based on the detection result of the detected light Lb, and thus allows for accurate estimation of solidification parameters.

[0138] <Modification 3 of the 6th Embodiment> The inspection device 501C shown in Figure 49 includes a guide member 36 in addition to the inspection device 501. The guide member 36 has the function of guiding the trajectory of the object T being conveyed by the belt 212C. The guide member 36 is positioned on the belt surface 212a of the belt 212C. The guide member 36 is not fixed to the belt 212C and is stationary with respect to the belt 212C moving in the conveying direction D1. The guide member 36 includes a pair of guide plates 37 and a pair of guide plates 38.

[0139] Each of the pair of guide plates 37 is plate-shaped with the left-right direction D3 as the thickness direction. The pair of guide plates 37 are arranged side by side with a gap in the left-right direction D3. The pair of guide plates 37 extend along the transport direction D1. The gap between the pair of guide plates 37 in the left-right direction D3 is greater than or equal to the gap between the objects T in the left-right direction D3. The pair of guide plates 38 are each connected to the pair of guide plates 37. The pair of guide plates 38 are arranged side by side with a gap in the left-right direction D3. The pair of guide plates 38 extend along a direction inclined with respect to the transport direction D1. The gap between the pair of guide plates 38 in the left-right direction D3 widens as they move away from the pair of guide plates 37 in the transport direction D1. The pair of guide plates 38 guide the objects T being transported in the transport direction D1 between the pair of guide plates 37. The objects T guided by the pair of guide plates 37 move along the pair of guide plates 37 in the transport direction D1.

[0140] As shown in Figure 50(a), at least one of the pair of guide plates 37 has through openings 37a and 37b. The through openings 37a and 37b are formed on the guide plate 37 at positions adjacent to each other in the transport direction D1. The through opening 37a is formed at a position that overlaps with the light emission unit 3 in the left-right direction D3. The through opening 37a allows the irradiation light La from the light emission unit 3 to pass through. The through opening 37b allows the detection light Lb directed toward the light detection unit 4 to pass through. The object T guided by the pair of guide plates 37 reaches a position facing the light emission unit 3 and the light detection unit 4 while being restricted by the pair of guide plates 37. At this time, the irradiation light La emitted from the light emission unit 3 passes through the through opening 37a and irradiates the side P2 of the object T. Of the illumination light La irradiated onto the side portion P2, the reflected light reflected by the object 12 is emitted from the side portion P2 as detection light Lb, passes through the passage opening 37b, and is detected by the photodetector 4. The method for measuring the detection light Lb is, for example, the TRS method, but other measurement methods such as the SRS method may also be used.

[0141] In the inspection device 501C, the movement of the object T is restricted by the guide member 36 to remain aligned with the transport direction D1. The guide member 36 also restricts the orientation of the object T so that it does not tilt. This ensures that the object T being transported by the belt 212C is irradiated with irradiation light La and that detection light Lb is detected from the object T. As a result, optical parameters can be calculated with high accuracy based on the detection result of detection light Lb, and thus solidification parameters can be estimated with high accuracy.

[0142] As shown in Figure 50(b), the guide plate 37 may have a passage opening 37c instead of passage openings 37a and 37b. In this case, the passage opening 37c is formed at a position that overlaps with both the light emission unit 3 and the light detection unit 4 in the left-right direction D3. The passage opening 37c allows both the irradiation light La from the light emission unit 3 and the detection light Lb toward the light detection unit 4 to pass through. Even with this configuration, the same effects as the inspection device 501C can be obtained.

[0143] <Modification 4 of the 6th Embodiment> The inspection device 501D shown in Figure 51 includes a pair of sensors 39 in addition to the inspection device 501C shown in Figure 49. The pair of sensors 39 detect whether or not the object T is in a position facing the light emitting unit 3 and the light detection unit 4. The pair of sensors 39 are arranged on the guide plate 37 at a pair of positions separated in the transport direction D1. The distance between the pair of sensors 39 in the transport direction D1 is greater than or equal to the distance between the object T in the transport direction D1. Each of the pair of sensors 39 is, for example, a light-emitting and receiving sensor that detects the presence or absence of the object T by emitting and receiving light.

[0144] When the pair of sensors 39 detect that the object T is facing the light emitting unit 3 and the light detection unit 4 (see Figure 51), the object T is irradiated with light La and the detection light Lb from the object T is detected. When the pair of sensors 39 do not detect that the object T is facing the light emitting unit 3 and the light detection unit 4 (see Figure 52), the object T is not irradiated with light La and the detection light Lb from the object T is not detected.

[0145] In the inspection device 501D equipped with a pair of sensors 39, when the object T is transported to a position facing the light emission unit 3 and the light detection unit 4, optical measurement using the irradiated light La can be performed automatically, making it easy to estimate solidification parameters based on optical parameters obtained from the detection results of the detected light Lb.

[0146] <Seventh Embodiment> The inspection device 601 shown in Figure 53 further comprises a dark box 40 in addition to the inspection device 1 of the first embodiment. The dark box 40 is, for example, a rectangular parallelepiped hollow container. The dark box 40 is made of a material that shields or absorbs light other than the irradiation light La and the detection light Lb. The dark box 40 has a pair of openings 40a. The pair of openings 40a are formed in the dark box 40 at a pair of positions facing the transport direction D1. Each of the pair of openings 40a allows the belt 212 and the object T transported by the belt 212 to pass through.

[0147] The light-emitting unit 3 and the light-detecting unit 4 are positioned inside the dark box 40 facing the object T and adjacent to each other. The light-emitting unit 3 and the light-detecting unit 4 may be positioned inside the dark box 40 facing each other with the object T in between. The light-emitting unit 3 and the light-detecting unit 4 may be in contact with the object T inside the dark box 40, or they may be at a distance from the object T inside the dark box 40.

[0148] Each opening 40a of the dark box 40 is covered by a plurality of partition members 41. Each of the plurality of partition members 41 is, for example, shaped like a strip with the vertical direction D2 as its longitudinal direction and the horizontal direction D3 as its short direction. Each partition member 41 is arranged in a row along the horizontal direction D3. Each partition member 41 extends along the vertical direction D2 from the edge of the opening 40a of the dark box 40 toward the belt surface 212a. Each partition member 41 may be in contact with the belt surface 212a or may be separated from the belt surface 212a.

[0149] Each partition member 41 is made of a soft material that shields or absorbs light other than the irradiation light La and detection light Lb, and is elastically deformed when subjected to pressure from the object T being transported in the transport direction D1. Suitable materials for each partition member 41 include flexible and scratch-resistant materials such as rubber pieces, vinyl pieces, sponge pieces, or brush pieces. When the object T is transported to the opening 40a of the dark box 40, each partition member 41 deforms as it is pressed by the object T, and receives the object T into the dark box 40 from the opening 40a. After irradiation with irradiation light La and detection of detection light Lb are performed inside the dark box 40, the object T is transported to the outside of the dark box 40 from the other opening 40a.

[0150] In the inspection device 601, irradiation with irradiation light La and detection of detection light Lb are performed in a space surrounded by the dark box 40 and a plurality of partition members 41. This reduces the risk of other light, other than the irradiation light La and detection light Lb, entering the light detection unit 4 from outside the dark box 40. As a result, optical parameters can be calculated accurately based on the detection result of the detection light Lb, and thus solidification parameters can be estimated accurately.

[0151] <Eighth Embodiment> In the inspection device 701 shown in Figure 54, the light emitting unit 3 is positioned facing the side P2 of the object T, and the light detection unit 4 is positioned facing the film 11 of the object T. In this case, the irradiation light La emitted from the light emitting unit 3 passes through the side P2 and is incident on the object 12. Of the irradiation light La incident on the object 12, the light scattered by the object 12 is emitted from the film 11 as detection light Lb and detected by the light detection unit 4. The measurement method for the detection light Lb is, for example, the TRS method, but other measurement methods such as the SRS method may also be used. The light detection unit 4 may be positioned facing the side P2. The light emitting unit 3 may be positioned facing the film 11. Even with the inspection device 701, the same effects as the inspection device 1 of the first embodiment can be obtained.

[0152] The following describes some variations of the eighth embodiment.

[0153] <Modification 1 of the 8th Embodiment> The inspection device 701A shown in Figure 55 further comprises a partition member 50 in addition to the inspection device 701. The partition member 50 is, for example, a cylindrical shape with a bottom. The partition member 50 is arranged to cover the upper part of the object T, including the film 11. The partition member 50 includes a bottom plate 55, a side plate 56, and an enclosure plate 57. The bottom plate 55 is positioned to face the film 11 in the vertical direction D2 at a certain distance from it. The bottom plate 55 is positioned to overlap with the object T in the vertical direction D2. The bottom plate 55 has a passage opening 55a that penetrates in the vertical direction D2. The passage opening 55a is formed in a position that overlaps with the light detection unit 4 in the vertical direction D2. The passage opening 55a allows the detection light Lb from the object T to pass through.

[0154] The side plate 56 extends from the edge of the bottom plate 55 toward the object T along the vertical direction D2. The side plate 56 extends to a position facing the side P2 of the object T in the left-right direction D3. The side plate 56 surrounds the upper part of the object T, including the film 11. The enclosure plate 57 is cylindrical in shape on the bottom plate 55, surrounding the passage opening 55a. The enclosure plate 57 is positioned inside the side plate 56 on the bottom plate 55. The enclosure plate 57 extends from the bottom plate 55 in the vertical direction D2 and faces the film 11.

[0155] The partition member 50 is made of a material that shields or absorbs light other than the detected light Lb directed toward the photodetector 4. Therefore, the optical path of the irradiated light La between the light emitter 3 and the object T and the optical path of the detected light Lb between the photodetector 4 and the object T are separated by the partition member 50. As a result, the inspection device 701A can reduce the risk that a portion of the irradiated light La from the light emitter 3 will become stray light and enter the photodetector 4. This allows for accurate calculation of optical parameters based on the detection result of the detected light Lb, and thus allows for accurate estimation of solidification parameters.

[0156] <Modification 2 of the 8th Embodiment> The inspection device 701B shown in Figure 56 further comprises a partition member 50A in addition to the inspection device 701. The partition member 50A is, for example, a cylindrical shape with a bottom. It is positioned to cover the upper part of the object T, including the film 11. In addition to the bottom plate 55 and side plates 56 of the partition member 50, the partition member 50A includes a light-shielding member 57A. The light-shielding member 57A is, for example, a pyramidal cylindrical body. The light-shielding member 57A is positioned to surround the area between the film 11 and the bottom plate 55. In cross-sections along the vertical direction D2 and the left-right direction D3, the light-shielding member 57A has a trapezoidal shape that narrows from the bottom plate 55 towards the film 11.

[0157] As shown in Figure 57, when viewed along the vertical direction D2, the area of ​​the light-shielding member 57A is smaller than the area of ​​the object T. Therefore, when viewed along the vertical direction D2, the light-shielding member 57A is located inside the object T. As shown in Figure 56, a portion of the light detection unit 4 inserted into the passage opening 55a is housed inside the light-shielding member 57A. The light-shielding member 57A is made of a material that shields or absorbs light other than the detected light Lb directed toward the light detection unit 4. The light-shielding member 57A is made of, for example, a black plate, a sponge piece, a vinyl piece, or a curtain.

[0158] In the inspection device 701B, the optical path of the irradiation light La between the light emission unit 3 and the object T, and the optical path of the detection light Lb between the light detection unit 4 and the object T are separated by a partition member 50A. Therefore, the inspection device 701B can reduce the risk that a portion of the irradiation light La from the light emission unit 3 will become stray light and enter the light detection unit 4. As a result, optical parameters can be calculated with high accuracy based on the detection result of the detection light Lb, and thus solidification parameters can be estimated with high accuracy.

[0159] <Modification 3 of the 8th Embodiment> The inspection device 701C shown in Figure 58 further includes a filter 60 in addition to the inspection device 701. The filter 60 is positioned between the light detection unit 4 and the object T. More specifically, the filter 60 is positioned on the optical path of the detected light Lb from the light detection unit 4 to the film 11 of the object T. The filter 60 is an optical filter or polarizing filter that selectively passes only the detected light Lb. In the inspection device 701C, the irradiation light La emitted from the light emission unit 3 passes through the side P2 and is incident on the object 12. Of the irradiation light La incident on the object 12, the light scattered by the object 12 is emitted from the film 11 as detected light Lb, passes through the filter 60 and is detected by the light detection unit 4. The filter 60 transmits only the detected light Lb. Therefore, the filter 60 reduces the risk of other light reflected by the film 11 being incident on the light detection unit 4.

[0160] Thus, by providing the filter 60, the inspection device 701C can reduce the risk of light other than the detected light Lb entering the photodetector 4. As a result, the inspection device 701C can accurately calculate optical parameters based on the detection result of the detected light Lb, and can accurately estimate coagulation parameters based on the optical parameters. The method for measuring the detected light Lb is, for example, the TRS method, but other measurement methods such as the SRS method may also be used. The light emission unit 3 may be positioned facing the side P2. The photodetector 4 may be positioned facing the bottom surface 10b of the container.

[0161] <Modification 4 of the 8th Embodiment> In the inspection device 701D shown in Figure 59, the light emitting unit 3 is positioned facing the side P2, and the light detection unit 4 is positioned facing the bottom surface 10b of the container. In this case, the irradiation light La emitted from the light emitting unit 3 passes through the side P2 and is incident on the object 12. Of the irradiation light La incident on the object 12, the light scattered by the object 12 is emitted from the bottom surface 10b of the container as detection light Lb and detected by the light detection unit 4. The measurement method for the detection light Lb is, for example, the TRS method, but other measurement methods such as the SRS method may also be used. The arrangement relationship between the light emitting unit 3 and the light detection unit 4 may be reversed. That is, the light detection unit 4 may be positioned facing the side P2, and the light emitting unit 3 may be positioned facing the bottom surface 10b of the container. Even with the inspection device 701D, the same effects as the inspection device 701 can be obtained.

[0162] This disclosure is not limited to the embodiments and modifications described above, and various other modifications are possible. For example, the embodiments and modifications described above may be combined with each other to the extent that they do not contradict each other, depending on the required purpose and effect.

[0163] The “substance” in this disclosure may be a food other than tofu. The “substance” may be an agricultural product such as an apple or a tomato. The “substance” may be, for example, deep-fried tofu dough such as thick fried tofu, deep-fried tofu, fried tofu for sushi, thin fried tofu, or ganmodoki. The “substance” may be a soy-based processed food such as yuba tofu, soy milk jelly, soy milk yogurt, or douhua. The “substance” may be a processed seafood product such as kamaboko, chikuwa, hanpen, fried kamaboko, or fish sausage. The “substance” may be an egg product such as egg tofu, boiled egg, pudding, chawanmushi, or meringue. The “substance” may be a raw milk processed product such as cheese or yogurt. The “substance” may be a processed meat product such as gelatin or ham or sausage. The “substance” may be a confectionery such as yokan, jelly, tokoroten, uiro, or gummy candy.

[0164] The “container” in this disclosure may be a combination of multiple connected packs (for example, a double pack or a six-pack). In this case, the container itself containing the object becomes larger, which reduces the risk of some of the irradiated light entering the photodetector as stray light.

[0165] 1, 1A, 1B, 1C, 1D, 1E, 101, 101A, 101B, 101C, 101D, 101E, 201, 201A, 201B, 301, 401, 401A, 401B, 501, 501A, 501B, 501C, 501D, 601, 701, 701A, 701B, 701C, 701D... Inspection device, 3, 3A, 3B... Light emission unit, 4, 4A, 4B... Light detection unit, 5... Processing unit, 10... Container, 11... Film, 12, 12A... Object, 52... Solidification parameter estimation unit, 53... Memory unit, A... Container opening (opening), La... Irradiation light, Lb... Detection light, T, TA, TB... Target object, φ2... Detection signal, φ22... Correlation information.

Claims

1. An inspection apparatus comprising: a light emission unit positioned facing an object, which includes a container made of a light-scattering material and a gel-like or gel-forming sol-like object contained in the container, and which emits irradiation light containing wavelengths that can penetrate the container toward the object; a light detection unit positioned facing the object, which detects detection light emitted from the object and transmitted through the container in response to the irradiation of the object with the irradiation light, and outputs a detection signal indicating the detection result of the detection light; and a processing unit that is communicably connected to the light detection unit and estimates solidification parameters indicating the degree of solidification of the object based on the optical parameters of the object obtained from the detection result.

2. The inspection apparatus according to claim 1, wherein the light emitting unit emits pulsed light as the irradiation light toward the object.

3. The inspection apparatus according to claim 1 or 2, wherein the object includes a film that closes the opening of the container from which the object is exposed, the film is made of a material that can transmit at least one of the irradiated light and the detected light, and the light reflectance to at least one of the irradiated light and the detected light is higher than that of the container, and the light emitting unit and the light detecting unit are each positioned to face the film or the container.

4. The inspection apparatus according to any one of claims 1 to 3, wherein the light emitting unit and the light detecting unit are positioned facing the container and are arranged adjacent to each other.

5. The inspection apparatus according to any one of claims 1 to 3, wherein the light detection unit is located on the opposite side from the light emission unit, with the object in between.

6. The inspection apparatus according to any one of claims 1 to 5, wherein at least one of the light emitting unit and the light detecting unit is in contact with the object.

7. The inspection apparatus according to any one of claims 1 to 5, wherein at least one of the light emitting unit and the light detecting unit is located at a predetermined distance from the object.

8. The inspection apparatus according to any one of claims 1 to 7, wherein the container includes a container top surface having an opening formed therein in which the object is exposed, and a container bottom surface located on the opposite side of the container top surface, and at least one of the light emitting unit and the light detecting unit is positioned facing the container bottom surface.

9. The inspection apparatus according to any one of claims 1 to 8, wherein the processing unit includes an optical parameter calculation unit that calculates the optical parameters of the object using the detection results, a storage unit that stores correlation information showing the correlation between the optical parameters and the solidification parameters, and a solidification parameter estimation unit that converts the optical parameters into the solidification parameters using the correlation information.

10. The inspection apparatus according to any one of claims 1 to 9, wherein the optical parameters include at least one of the equivalent scattering coefficient, average optical path length, light intensity, counting rate, and the nth moment of the time response waveform.

11. The inspection apparatus according to any one of claims 1 to 10, wherein the coagulation parameter includes at least one of viscosity, solid content concentration, and water retention rate.

12. An inspection method comprising: emitting irradiation light containing a wavelength that can penetrate the container toward an object, which includes a container made of a light-scattering material and a gel-like or gel-forming sol-like object contained in the container; detecting detection light emitted from the object and transmitted through the container in response to the irradiation of the object with the irradiation light, and outputting a detection signal indicating the detection result of the detection light; and estimating solidification parameters indicating the degree of solidification of the object based on the optical parameters of the object obtained from the detection result.

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