WO2020050012A1

WO2020050012A1 - Food inspection device and food inspection method

Info

Publication number: WO2020050012A1
Application number: PCT/JP2019/032526
Authority: WO
Inventors: 生嶋　健司; 貴浩前川; 文仁村山; 惇伊藤
Original assignee: 国立大学法人東京農工大学; 株式会社極洋
Priority date: 2018-09-04
Filing date: 2019-08-21
Publication date: 2020-03-12
Also published as: JP2020038127A; JP6652999B1

Abstract

One food inspection device 100 according to this invention comprises: a resonance unit 40 including a pair of electrodes 7a, 7b and a coil; a transmission unit 5a for producing a first AC signal in the resonance unit 40; a reception unit 5b for, when food 10 is disposed between the electrodes 7a, 7b, receiving at least one type of second AC signal selected from the group consisting of an AC signal reflected by the resonance unit 40, an AC signal that has passed through the resonance unit 40, an AC signal comprising the current flowing through the resonance unit 40, and an AC signal comprising the voltage produced in the resonance unit 40; a measurement unit (computer 90) for measuring at least one selected from the group consisting of the center frequency of a resonance spectrum characteristic based on the second AC signal, the bandwidth of the resonance spectrum characteristic based on the second AC signal, and the signal strength of a specific frequency in the resonance spectrum characteristic based on the second AC signal; and a correction means for carrying out correction for reducing the influence of the variation in the capacitance of an air layer between the food 10 and an electrode 7a, 7b.

Description

Food inspection device and food inspection method

The present invention relates to a food inspection apparatus and a food inspection method for food.

As for foods, the state of water, salt concentration, or percentage of lipids contained in the foods can affect the finished state of processed or cooked foods. In particular, in the case of frozen foods, the state of water (whether ice or water), the concentration of salt, or the percentage of lipids contained in the food is determined by the finished state of the processed or cooked food (final product state). In addition, it can affect the quality of the food. In addition, various indices such as a water content, a salt concentration, and a lipid ratio that can be included in the food also affect the finished state of the processed or cooked food and the quality of the food. Therefore, for producers, those engaged in logistics, and consumers (consumers), such indicators that affect the quality of food are based on the recent circumstances in which "food safety and security" is particularly attracting attention. That is, of course, a very important concern.

For example, in the case of frozen food, the expected temperature and quality may not be achieved depending on the conditions of ice and / or water contained in the food. Specifically, the food which should be heated after full thawing is heated in the half-thaw state may not be able to sufficiently heat the food. Conversely, by completely defrosting food that should be processed at low temperature after it has been half-thawed, the food cannot be kept at a sufficiently low temperature for a certain period of time, maintaining the quality of the food. It can be difficult to do so. In addition, irrespective of whether or not the food is frozen, the expected quality may not be achieved depending on the salt concentration or the lipid ratio.

Heretofore, there have been disclosed some devices or methods for examining the temperature and frozen / thawed state of food, or the state of quality deterioration of food, focusing on the electric conductivity or capacitance of food (Patent Documents 1 to 4). 4, and Non-Patent Document 1).

As an example, the state of water contained in a food varies with the temperature of the food, and monitoring the temperature and / or temperature change is a major method for quality control of food that has been conventionally adopted. is there. Typically, the monitoring of the temperature and / or temperature change of the food is a direct monitoring method using a thermometer, a non-destructive monitoring method using thermography, or, in some cases, a human tactile sensation. Ambiguous indicators are also employed. Therefore, the applicant of the present application has previously reported, based on an objective index of complex permittivity including permittivity and electric conductivity, the state of water, the concentration of salt contained in food, or the proportion of lipid (typically, Has developed and disclosed an inspection device and method for nondestructively measuring or inspecting the state of food represented by water / oil ratio (Patent Document 5).

International Publication No. WO00 / 14522 JP 2005-337986 A JP-A-8-75806 JP-A-4-73582 JP-A-2017-191099

However, in the direct monitoring method using a thermometer, the thermometer is inserted into the food to be inspected and used. As a result, the food cannot be sold as a product, and the food must be disposed of. Further, when thermography is used, even if the surface (surface layer) of the food can be measured, it is difficult to measure the inside of the food. In addition, the ambiguous index of human touch is a personal index and lacks versatility and permanence.

Even if the food temperature and / or temperature change can be monitored, it does not mean that the state of water contained in the food is correctly understood. As described in Patent Document 5, especially in the case of frozen foods, the state of water in food during the process from the frozen state to the thawed state, or vice versa, from the thawed state to the frozen state, is usually Often, it does not appear in the index of the temperature of the food. Therefore, it is very difficult to grasp the state of water contained in the food by using the index of temperature.

On the other hand, as a result of the present inventors' earnest efforts and research and analysis, in the invention disclosed in Patent Literature 5, preferably, the shape and / or size of the food disposed between the electrodes is determined by the shape and / or size of the electrodes. It has been found that consideration and consideration for the electric capacity of the air layer existing between the food and the food are required.

The present inventors have worked diligently on research and analysis in order to further increase the inspection accuracy of the inspection device and the inspection method disclosed in Patent Document 5. As a result, especially in the case of inspecting a large number of foods having irregular shapes and / or sizes of individual foods, the electric capacity of an air layer existing between each food disposed between the electrodes and the electrode is increased. Because of the fluctuation, it became clear that the influence of the fluctuation of the electric capacity on the inspection result cannot be ignored.

In addition, as shown in FIG. 7B of Patent Document 5 disclosed by the present applicant, when a food containing both water and lipid (oil) is to be inspected, the mixing ratio of water and lipid (oil) is determined. It is of great interest in the food industry to more accurately test for differences in center frequency and / or bandwidth that vary due to different. However, if the electric capacity of the air layer existing between the food and the electrode arranged between the electrodes fluctuates greatly, it becomes difficult to grasp the mixing ratio of water and lipid (oil) with high accuracy. .

Therefore, research and development of food inspection devices and methods that can accurately quantify the frozen or thawed state of water without using the index of temperature can be said to be still in the middle.

The present invention realizes an inspection apparatus and an inspection method capable of measuring or inspecting the state of food, which is exemplified by the state of water, the salt concentration, or the proportion of lipid, with higher accuracy and nondestructively. It greatly contributes to.

The present inventors have examined foods containing both water and lipid (oil) even if the shapes and / or sizes of the foods to be inspected are different from each other. Even in such a case, an examination apparatus and an examination method capable of reducing the influence of the air layer existing between the food and at least one of the electrodes were repeatedly examined through trial and error.

として As an example, the present inventors have studied and analyzed the influence of the electric capacity of the air layer based on the equivalent circuit diagram for analysis shown in FIG.

ＦF in FIG. 8 means a food to be inspected. Therefore, the electric capacity (Cf) and the resistance value (Rf) in FIG. 8 are the electric capacity and the resistance value of the food F, respectively. Further, Q in FIG. 8 is an insulating thin plate provided between the food F and the electrode (usually, the lower electrode). Further, L in FIG. 8 is the inductance of the coil, and RL is the resistance value of the coil near the resonance frequency. Further, as shown in FIG. 8, a parasitic capacitance (Cstr) is set. Further, Rout in FIG. 8 is an output impedance. Note that, since the insulating thin plate is not necessarily required, omitting the electric capacity (Cins) of the thin plate is one aspect that can be adopted.

Here, among the nine parameters shown in FIG. 8, Cf and Rf of the food F are unknown and are to be inspected. On the other hand, in order to derive Cf and Rf, it is necessary that all the remaining seven parameters (L, RL, Cair, Cins, Cstr, Rout, and V) in the equivalent circuit diagram are known or substantially constant. Can be The inventors have shown that among these, Cair is a number that is sensitive to the shape and / or size of the food and is a number that predominantly affects the center frequency and / or bandwidth. It was learned by repeating the experiment. Therefore, the change in the Cair affected by the shape and / or the size of the food placed between the electrodes is substantially negligible, and the state of the food is highly accurately determined by utilizing the center frequency and / or the bandwidth. Various examinations were conducted for inspection.

As a result, the present inventors have found that it is possible to more accurately inspect the state of food by creating a solution that can reduce the influence of the air layer in terms of hardware and / or software. Obtained. The present invention has been created based on the above-described viewpoints.

One food inspection device of the present invention for achieving the above technical effects includes a resonance unit including a pair of electrodes and a coil, a transmission unit that generates a first AC signal to the resonance unit, When an AC signal is disposed between the electrodes, an AC signal reflected on the resonance unit, an AC signal transmitted through the resonance unit, an AC signal including a current flowing through the resonance unit, and an AC signal including a voltage generated in the resonance unit A receiving unit that receives at least one type of second AC signal selected from a group of signals, a center frequency of a resonance spectrum characteristic based on the second AC signal, a bandwidth of a resonance spectrum characteristic based on the second AC signal, And a measuring unit that measures at least one selected from a group of signal intensities at a specific frequency in a resonance spectrum characteristic based on the second AC signal, and a capacitance of an air layer between the electrode and the food. Shadow of change And a correcting means for correcting to reduce.

According to this food inspection device, when the first AC signal including the center frequency is provided to the above-described resonance unit, the reception unit receives the above-described second AC signal when the food is arranged between the pair of electrodes in the resonance unit. Receive. In addition, the measurement unit of the food inspection apparatus includes a center frequency of a resonance spectrum characteristic based on the second AC signal, a bandwidth of a resonance spectrum characteristic based on the second AC signal, and a resonance spectrum based on the second AC signal. By measuring at least one selected from a group of signal intensities at a specific frequency in the characteristic, it is possible to obtain a change in the dielectric constant of the food and / or an electrical conductivity (or resistivity). Become. As a result, the state of water, the concentration of salt contained in food, or the state of food represented by the ratio of lipids (typically, the ratio of water to oil) can be measured with high accuracy and nondestructively. Can be inspected. In addition, according to this food inspection apparatus, since there is provided a correction unit for performing a correction for reducing an influence of a change in an electric capacity of an air layer between the electrode and the food, each food to be inspected is provided. Even if the shapes and / or sizes of the foods are different from each other, or even if the food containing both water and lipids (oil) is to be inspected, the state of the food is more accurately than before. Can be inspected.

Note that the measurement unit measures at least the center frequency and / or bandwidth of the resonance spectrum characteristic based on the second AC signal described above, because the change in the dielectric constant of the food and the electrical conductivity (or resistance) Rate), which is a preferred embodiment.

Further, in the above-described food inspection device, a more preferable aspect is that the correction means has the following configurations (a1), (a2), and (a3).
(A1) an arrangement unit for arranging the above-mentioned food;
(A2) A displacement mechanism that displaces the arrangement portion and the electrode in a direction of relatively approaching or separating while the arrangement portion faces the electrode (however, the electrode may also serve as the arrangement portion).
(A3) When the food is disposed between the electrodes, the second thickness of the air layer for each food is substantially determined based on the first thickness of the food to be inspected measured in advance. A control unit for controlling the displacement mechanism so as to be constant

According to the food inspection device of this preferred embodiment, the thickness of the air layer when each food to be inspected is arranged between the electrodes is adjusted using the displacement mechanism. Therefore, even if the shapes and / or sizes of the foods to be inspected are different from each other, or if the foods containing both water and lipid (oil) are to be inspected, Can also be adjusted to reduce the effect of changes in the capacitance of the air layer.

Further, in the above-mentioned food inspection device, another more preferable aspect is that the above-mentioned correction means has the following configuration (b1).
(B1) Based on the first thickness of each of the foods to be inspected measured in advance, based on the second thickness of the air layer when the foods are arranged between the electrodes. The above-mentioned center frequency and / or the above-mentioned bandwidth, which are calculated with the capacitance as one of the elements, are used to determine the reference between the electrode and the reference food when the reference food is placed between the electrodes. Calculation means for calculating by comparing with a reference center frequency and / or a reference bandwidth corresponding to the thickness of the air layer

According to the food inspection apparatus of another preferred aspect, the thickness of the air layer when each food to be inspected is arranged between the electrodes is calculated using the calculation unit. In order to reduce or substantially eliminate the influence of the capacitance due to the thickness of the air layer, even if the shape and / or size of each food to be inspected are different from each other, Alternatively, even when a food containing both water and lipid (oil) is to be inspected, adjustment can be made to reduce the effect of a change in the electric capacity of the air layer.

Further, one food inspection method of the present invention for achieving the above-described technical effects includes an arrangement step of arranging food between the electrodes of a resonance unit including a pair of electrodes and a coil, and A correction step of performing a correction for reducing the effect of a change in the capacitance of the air layer between the electrode and the food when the electrode is disposed between the electrodes, and generating a first AC signal to the resonance unit. The transmitting step, and when the food is placed between the electrodes, an AC signal reflected on the resonance section, an AC signal transmitted through the resonance section, an AC signal including a current flowing through the resonance section, and the resonance section. Receiving at least one type of second AC signal selected from a group of AC signals consisting of a voltage generated at a center frequency of a resonance spectrum characteristic based on the second AC signal, based on the second AC signal. The bandwidth of the resonance spectral characteristic; Comprising a measuring step of measuring at least one selected from the group of the signal intensity of a specific frequency in the resonance spectral properties based on the AC signal.

According to this food inspection method, when the first AC signal including the center frequency is provided to the above-described resonance unit, the above-described second AC signal when the food is arranged between the pair of electrodes in the resonance unit is received. become. Furthermore, according to the food inspection method, the center frequency of the resonance spectrum characteristic based on the second AC signal, the bandwidth of the resonance spectrum characteristic based on the second AC signal, and the resonance spectrum characteristic based on the second AC signal are different. The measurement step of measuring at least one selected from a group of signal intensities at a specific frequency makes it possible to obtain a change in dielectric constant and / or an electrical conductivity (or resistivity) of the food. . As a result, the state of water, the concentration of salt contained in food, or the state of food represented by the ratio of lipids (typically, the ratio of water to oil) can be measured with high accuracy and nondestructively. Can be inspected. In addition, according to this food inspection apparatus, since each of the foods to be inspected is provided with a correction step for performing a correction for reducing the influence of a change in the electric capacity of the air layer between the electrode and the food, Even if the shapes and / or sizes of the foods are different from each other, or even if the food containing both water and lipids (oil) is to be inspected, the state of the food is more accurately than before. Can be inspected.

In the above-described measurement step, at least measuring the center frequency and the bandwidth of the resonance spectrum characteristic based on the second AC signal is performed by changing the dielectric constant of the food and the electrical conductivity (or resistivity). This is a preferred embodiment because it is possible to obtain

Further, in the above-described food inspection method, a more preferable aspect is that the above-described correction step includes the following step (c1).
(C1) The second thickness of the air layer for each food when the food is disposed between the electrodes based on the first thickness of the food to be inspected previously measured for each food. A displacing step in which a disposing portion for disposing the food is opposed to the electrode such that the disposing portion and the electrode are relatively close to or separated from each other so that the food is substantially constant.

According to the food inspection method of one preferred aspect, the thickness of the air layer when each food to be inspected is arranged between the electrodes can be adjusted by the displacement step. Even if the shape and / or size of each food to be inspected are different from each other, or even if a food containing both water and lipid (oil) is to be inspected, Adjustments can be made to reduce the effects of changes in the capacitance of the air layer.

Further, in the above-described food inspection method, another more preferable aspect is that the above-described correction step has the following configuration (d1).
(D1) the above-mentioned electricity based on the second thickness of the above-mentioned air layer when the food is arranged between the electrodes, based on the first thickness of each of the above-mentioned foods to be inspected measured in advance. The above-mentioned center frequency and / or the above-mentioned bandwidth calculated with the capacity as one of the elements is used to determine the reference air between the electrode and the reference food when the reference food is placed between the electrodes. A calculating step of calculating by comparing with a reference center frequency and / or a reference bandwidth corresponding to the layer thickness

According to the food inspection method of another preferred aspect, the thickness of the air layer when each food to be inspected is disposed between the electrodes is calculated by the calculation step. Correction calculations can be performed to reduce or substantially eliminate the effect of capacitance due to the thickness of the air layer, even if the shapes and / or sizes of the foods to be inspected are different from each other, or Even when a food containing both water and lipid (oil) is to be inspected, adjustment can be made to reduce the influence of the change in the electric capacity of the air layer.

By the way, in the present application, “signal intensity” is a concept including “standardized intensity”, “non-standardized intensity”, and “reflection intensity” in the embodiment described later.

According to one food inspection apparatus of the present invention, since there is provided a correction means for performing a correction for reducing an influence of a change in an electric capacity of an air layer between the electrode and the food, each of the inspection target Even if the shapes and / or sizes of the foods are different from each other, or even if the food containing both water and lipid (oil) is to be inspected, the accuracy of the food is higher than before. It is possible to check the condition.
Further, according to one food inspection method of the present invention, since there is provided a correction step for performing a correction for reducing the effect of a change in the capacitance of the air layer between the electrode and the food, the inspection target and Even if the shape and / or size of each food is different from each other, or even if the food containing both water and lipid (oil) is to be inspected, the accuracy is higher than before. It becomes possible to inspect the condition of food.

It is a lineblock diagram of a food inspection device of a 1st embodiment. It is a lineblock diagram of a food inspection system of a 1st embodiment. It is a lineblock diagram of a food inspection device of a 3rd embodiment. It is a lineblock diagram of a food inspection system of a third embodiment. It is a graph in 3rd Embodiment which shows the relationship between the thickness of the air layer between an electrode and foodstuffs, and center frequency about the foodstuff which was fully thawed. It is a graph which shows the relationship between the thickness of the air layer between an electrode and foodstuffs, and the bandwidth of fully thawed foodstuffs in the third embodiment. As reference example, is a graph showing the respective resonance spectrum during freezing and during thawing of the value of t ₂ is 30 mm. It is an equivalent circuit diagram for analysis.

Reference Signs List 5 Network analyzer

5a Transmitting unit

5b Receiving unit 6

Coil

7a, 7b Electrode 10 Food 11 Thermocouple 12 Temperature measuring device 20 Transport mechanism 30 Displacement mechanism 35 Control unit 40 Resonant unit 50 Measuring device 60 Imaging unit 70 Speed measuring unit 80 Weighing unit 90 Computer 100,200 Food inspection device 900,920 Food inspection system

として As an embodiment of the present invention, a food inspection device and a food inspection method will be described in detail with reference to the accompanying drawings. In this description, common parts are denoted by common reference symbols throughout the drawings unless otherwise specified. In addition, in the drawings, elements of the present embodiment are not necessarily described with keeping the scale of each other. Furthermore, some reference numerals may be omitted to make each drawing easier to see.

<First embodiment>
(Description of food inspection device)
The food inspection device 100 according to the present embodiment will be described. FIG. 1 is a configuration diagram of a food inspection apparatus 100 for food according to the present embodiment. In the present embodiment, the aspects and effects of the food inspection apparatus 100 and the method of inspecting the food using the food inspection apparatus 100 are described in terms of the food to be inspected (for example, seafood, more specifically, , Fish) 10.

As shown in FIG. 1, the food inspection apparatus 100 according to the present embodiment includes a pair of an upper electrode 7 a and a lower electrode 7 b, a resonance unit 40 including a coil 6, and a displacement mechanism that moves the upper electrode 7 a up and down. 30, a transmitting unit 5a (typically, a known function generator), a receiving unit 5b (typically, a known spectrum analyzer), and resonance spectrum characteristics based on an AC signal received by the receiving unit 5b. A measuring unit for measuring the center frequency and / or the bandwidth.

Further, in the present embodiment, the displacement mechanism 30 is connected to the computer 90 or controlled by the control unit 35 provided in the computer 90, and utilizes a known servomotor to accurately (for example, positioning accuracy ± 0.2 mm). Hereinafter) the upper electrode 7a can be moved up and down. As a result, the displacement mechanism 30 can apply a displacement in a direction in which the lower electrode 7b and the upper electrode 7a are relatively close to or separated from each other while the lower electrode 7b on which the food 10 is arranged faces the upper electrode 7a. .

Here, in a scene where many foods 10 having irregular shapes and / or sizes of individual foods 10 are inspected, or in a scene where foods containing both water and lipid (oil) are to be inspected, The thickness of the air layer existing between each food 10 disposed between the electrode 7a and the lower electrode 7b and the upper electrode 7a (corresponding to the “second thickness”. This embodiment and other embodiments) The same applies to the embodiment (including the modified example).) The electric capacity of the air layer changes according to the change of t ₂ ) in FIG.

Therefore, in the food inspection apparatus 100 including the displacement mechanism 30, when inspecting the food 10 whose thickness (height) has been inspected in advance, the thickness of the food 10 (corresponding to the “first thickness”. ), The displacement mechanism 30 can be controlled so that the thickness of the air layer (t _{2 in} FIG. 1) is substantially constant.

More specifically, the control unit 35 causes the lower electrode 7b and the upper electrode 7a to be relatively close to or separated from each other by the displacement mechanism 30 while making the lower electrode 7b on which the food 10 is arranged face the upper electrode 7a. By giving the displacement in the direction, the thickness of the air layer for each food 10 can be made substantially constant. Note that the control unit 35 can serve as a correction unit that performs correction for reducing the influence of a change in the electric capacity of the air layer between the upper electrode 7a and the food 10. Further, in the present embodiment, the lower electrode 7b also plays a role as an arrangement portion for arranging the food item 10.

Here, in the present embodiment, the control unit 35 controls the displacement mechanism 30 based on the above-described positioning accuracy of the servo motor so that the thickness of the air layer (t _{2 in} FIG. 1) is substantially constant. However, the positioning accuracy that can be adopted in the present embodiment is not limited to ± 0.2 mm or less. For example, the thickness of the air layer (t _{2 in} FIG. 1) may be made substantially constant within the range of ± 0.00004 mm or less to ± 0.00025 mm or less, which is the positioning accuracy of other known servomotors. This is an example of adopting the present embodiment. However, as long as at least a part of the effect of the present embodiment is achieved, the meaning of the term “substantially constant” is not limited to the above numerical range.

In the present embodiment, the computer 90 has a role of giving an instruction to the control unit 35 and also has a role of the above-described measuring unit. Hereinafter, "inspection or measurement" of the food 10 may be collectively referred to as "inspection". Further, “measurement or inspection” of the food 10 may be collectively expressed as “inspection”.

By the way, the transmitting unit 5a, the receiving unit 5b, the coil 6, and the resonance unit 40 according to the present embodiment all have the same functions as the transmitting unit 5a, the receiving unit 5b, the coil, and the resonance unit disclosed in Patent Document 5. Is the same. The pair of upper electrode 7a and lower electrode 7b of the present embodiment is the same as the pair of electrodes disclosed in Patent Document 5 except that the displacement mechanism 30 and the control unit 35 are provided. is there. Therefore, for example, the transmission unit 5a generates a first AC signal including the center frequency for the resonance unit 40. When the food 10 is disposed between the upper electrode 7a and the lower electrode 7b, the receiver 5b receives an AC signal reflected by the resonator 40, an AC signal transmitted through the resonator 40, and flows through the resonator 40. At least one type of second AC signal selected from a group of an AC signal including a current and an AC signal including a voltage generated in the resonance unit 40 is received.

In the present embodiment, a function generator is used as the transmitting unit 5a, and a spectrum analyzer is used as the receiving unit 5b, but the present embodiment is not limited to such an aspect. For example, using another alternative device disclosed in Patent Document 5 is another mode that can be adopted.

{Circle around (1)} As described above, the resonance section 40 includes at least one pair of the upper electrode 7 a and the lower electrode 7 b and the coil 6. In the present embodiment, the resonance section 40 is a series resonance circuit formed by connecting the coil 6 and a capacitor including the upper electrode 7a and the lower electrode 7b in series. At the time of inspection by the food inspection device 100, the food 10 is placed between the upper electrode 7a and the lower electrode 7b, and this state is regarded as a capacitor.

Further, although not illustrated in FIGS. 1 and 2, when using the food inspection device 100, an insulating layer or an insulator (for example, an acrylic thin plate) is disposed between the upper electrode 7 a and the lower electrode 7 b. This is also one mode that can be adopted. For example, during the inspection of the present embodiment, water (including water droplets) that is present by adhering to the food 10, water (including water droplets) that is present when moisture contained in the food 10 appears on the outer periphery or surface thereof, And / or water (including water droplets) originally present on the outer periphery or surface of the food 10 directly contacts the upper electrode 7a or the lower electrode 7b, or intervenes between the lower electrode 7b and the food 10. Providing the insulating layer or the insulator in order to prevent this from occurring with high accuracy is a preferable aspect from the viewpoint of improving inspection accuracy. In the above-described example, the insulating layer or the insulator plays a role as an arrangement portion for arranging the food 10.

In addition, although not illustrated in FIGS. 1 and 2, the distance between the upper electrode 7 a and the lower electrode 7 b of the portion facing each other without the food 10 is higher than that of the portion facing the food 10. Bending a part of the upper electrode 7a and the lower electrode 7b so as to be shorter than the distance between the electrode 7a and the lower electrode 7b is also a preferable embodiment that can be adopted.

Further, in the food inspection device 100 of the present embodiment, the receiving unit 5b and a known temperature measuring device 12 (in the present embodiment, manufactured by KEYENCE, model NR-1000). The computer 90 of the present embodiment can control each step for inspecting the state of the food 10 (hereinafter, also referred to as “inspection step”). The computer 90 also stores information (for example, temperature, resonance spectrum characteristics, center frequency (fr) of the resonance spectrum characteristics, and bandwidth (Δfr) of the resonance spectrum characteristics) obtained from the receiving unit 5b and the temperature measuring device 12. It may also be used to store, display the information, and / or analyze the information. In the food inspection device 100 according to the present embodiment, the thermocouple 11 and the temperature measuring device 12 can be omitted because they are devices for checking a temperature change of the food 10 for reference.

The computer 90 that plays the role of the measuring unit of the present embodiment can monitor or integrally control the above-described processing using, for example, an inspection program for inspecting the state of the food 10 described above. For example, in the present embodiment, the inspection program is stored on a known recording medium such as an optical disk inserted into a hard disk drive in the computer 90 or an optical disk drive provided in the computer 90. The storage destination is not limited to this. In addition, the inspection program can monitor or control the above-described processing via a known technique such as a local area network or an Internet line.

In another embodiment, the control unit 35 is provided separately from the computer 90 in place of the computer 90 having the control unit 35 as in the present embodiment.

(Explanation of food inspection method)
By using the food inspection device 100 having the above-described configuration, by measuring the center frequency and the bandwidth of the resonance unit 40, the state of the food 10 disposed between the upper electrode 7a and the lower electrode 7b (for example, (Freezing / thawing state).

More specifically, first, in the food inspection method according to the present embodiment, an object to be inspected by the food inspection apparatus 100 whose thickness (height) (t _{1 in} FIG. ₁ ) is measured in advance by a known measuring unit. An arrangement step of arranging a certain food item 10 between the upper electrode 7a and the lower electrode 7b provided in the resonance section 40 is performed. In the present embodiment, the thickness (height) of the food 10 measured in advance corresponds to the “first thickness”. In addition, the above-mentioned known measuring means includes, for example, manual measurement or measurement using a known measuring instrument.

After the food 10 is placed, based on the thickness (height) (t _{1 in} FIG. 1) of the food 10 obtained by pre-measurement, the control unit 35 sets the air space for each food 10 Is performed (an example of a correction process, the same applies hereinafter) for controlling the displacement mechanism 30 so that the thickness (t _{2 in} FIG. 1) is substantially constant. More specifically, in the displacing step, while the lower electrode 7b on which the food 10 is disposed is opposed to the upper electrode 7a, a displacement is provided in a direction in which the lower electrode 7b and the upper electrode 7a are relatively close to or separated from each other. Thereby, the thickness of the air layer for each food 10 can be made substantially constant.

後 After the above-described displacement step is performed, the food inspection apparatus 100 performs a transmission step of generating a first AC signal including the center frequency for the resonance unit 40 using the transmission unit 5a.

The receiving unit 5b receives the second AC signal reflecting the state of the food 10. Specifically, when the food 10 is disposed between the

electrodes

7a and 7b, an AC signal reflected on the resonance unit 40, an AC signal transmitted through the resonance unit 40, an AC signal including a current flowing through the resonance unit 40, and resonance. A receiving step of receiving at least one type of second AC signal selected from a group of AC signals including a voltage generated in the unit 40 is performed. After that, the measurement unit carried by the computer 90 (more specifically, the computer 90, the transmission unit 5a, and the reception unit 5b) measures the center frequency and / or the bandwidth of the resonance spectrum characteristic based on the received second AC signal. Is performed.

In the case where a plurality of foods 10 are to be inspected continuously, the displacement process of the present embodiment is performed for each food 10 before measuring the center frequency and the bandwidth of the resonance unit 40.

By the way, the range of the center frequency of the resonance section 40 is not particularly limited. However, the range of the center frequency of the resonance section 40 is preferably 10 kHz or more and less than 100 MHz for the reason described later.

(4) If the frequency is 100 MHz or more, the stray capacitance of the device becomes a problem, and it becomes difficult to manufacture an appropriate resonance circuit. Further, there is a problem that the cost of the inspection apparatus increases. Furthermore, if 1 kHz or 10 MHz is adopted as the center frequency of the resonance section 40, there arises a problem that the electric conductivity of ice and water becomes almost equal. Therefore, it is a preferable aspect that the range of the center frequency of the resonance section 40 is not less than 10 kHz and less than 100 MHz.

The second AC signal is an AC signal reflected by the resonance unit 40, an AC signal transmitted through the resonance unit 40, an AC signal including a current flowing through the resonance unit 40, and an AC signal including a voltage generated at the resonance unit 40. At least one selected from the group. In addition, the receiving unit 5b, which can also serve as a measuring unit of the food inspection device 100 of the present embodiment, obtains a resonance spectrum characteristic based on the above-described second AC signal, and obtains a center frequency and / or a band of the resonance spectrum characteristic. Measure the width.

Here, the present inventors inspected about 100 fish (more specifically, coho salmon) as an example of the food 10 using the food inspection apparatus 100 of the present embodiment. Specifically, using the displacement mechanism 30 whose positioning accuracy is ± 0.2 mm or less, the t ₂ for each food 10 is set to a specific value of 5 mm to 50 mm (more preferably, 20 mm or more, or 30 mm or less). A displacement step (an example of a correction step; the same applies hereinafter) controlled so as to be a distance was employed, and about 100 fish were inspected. As a result, when using no displacement mechanism 30, for example, (a different viewpoint, about 5% for t ₂₎ is about 1.5% the thickness of the fish or by different, is a frozen state or a decompressed state Is no longer easy to determine. On the other hand, by employing the present embodiment, (a different viewpoint, about 5% for t ₂₎ said thickness is about 1.5% for different about 70% of the number of fish from each other, determine that the thawing state The advantage was that it became possible to do so.

By the way, in the present embodiment, the displacement mechanism 30 moves the upper electrode 7a up and down, but the electrode moved by the displacement mechanism 30 of the present embodiment is not limited to the upper electrode 7a. For example, the displacement mechanism 30 moves the lower electrode 7b up and down instead of or together with the upper electrode 7a, so that the arrangement portion of the present embodiment and the upper electrode 7a or the lower electrode 7b This is a preferred aspect of the present embodiment, in which it is also possible to employ a method of displacing in the direction of relatively approaching or separating.

<Second embodiment>
FIG. 2 is a configuration diagram of a food inspection system 900 of the present embodiment including the food inspection device 100. Therefore, description overlapping with the first embodiment (representatively, description of the food inspection apparatus 100) may be omitted. In addition, in order to make the drawing easy to see, the transmitting unit 5a, the receiving unit 5b, the resonance unit 40, the thermocouple 11, and the temperature measuring device 12 shown in FIG. 1 directly or indirectly serve as a measuring unit. The connection to the computer 90 is not shown. The relationship between the computer 90 and the transmitting unit 5a, the receiving unit 5b, the resonance unit 40, the thermocouple 11, and the temperature measuring device 12 is as described in FIG.

The food inspection system 900 according to the present embodiment moves the food 10 from the left side to the right side in FIG. 2 (in the direction P in FIG. 2) using the transport mechanism 20 represented by a known belt conveyor. The transfer speed (including the speed 0) of the transfer mechanism 20 can be monitored or controlled by the computer 90, for example. In the process of moving the food 10, the food inspection system 900 of the present embodiment can perform some or all of the following steps (S1) to (S4).
(S1) the thickness of the food 10 (height) by measuring the (t _a in FIG. _2), at least the thickness of the food 10 (height) signal is measured and outputs a measuring instrument (for example, known laser rangefinder 2.) Thickness (height) gauge side process using 50) (S2) The speed of the food 10 moving at a constant speed passing through a specific position (V _{a in} FIG. 2) and the tip of the food 10 Speed measurement step using speed / time measurement means (for example, a known speedometer and clock) 70 for measuring the time until the rear end passes through the position. (S3) Image at least the outer shape of food 10 An imaging unit (for example, a digital camera equipped with a known imaging device) 60 that outputs an image signal for measuring at least a length (L _{a in} FIG. 2) and a width (W _{a in} FIG. 2) in plan view is used. (S4) The weight of the food 10 was measured and Both were used weighing unit 80 for outputting a weight signal of food 10, weighing process

In the present embodiment, the thickness (height) of the food 10 corresponds to the “first thickness”. Further, the image in the “plan view” described above means an image when viewed from the imaging unit 60 in the direction of α in FIG. Therefore, in the transport mechanism 20, an image when looking down from just above or almost directly above the mounting surface on which the moving or stationary food item 10 is mounted is a typical planar view image.

The weighing unit 80 of the present embodiment is a known weighing device that can measure the weight of the conveyed food product 10 in real time. As shown in FIG. 2, the weighing unit 80 is incorporated as a part of the transport mechanism 20. As an example, the weight of the food (eg, fish) 10 that passes above the weighing unit 80 or temporarily stops above the weighing unit 80 is measured in a state where the weighing unit 80 is incorporated under a known belt conveyor. can do.

配置 In addition, the arrangement order of the weighing unit 80, the speed / time measurement unit 70, the imaging unit 60, and the measuring device 50, which is drawn from the left side to the right side of the paper in FIG. 2, is not limited to the order shown in FIG.

Next, a description will be given of a typical embodiment in which some or all of the specific steps (S1) to (S4) are performed, and modifications thereof.

In the present embodiment, only the step (S1) of the food inspection system 900 is employed.

Specifically, a signal shown in the following (z1) is output to the computer 90.
(Z1) as shown in FIG. 2, to rest on the transport mechanism 20, or by the transport mechanism 20 the thickness of the food 10 in the upper moving (height) instrument 50 was measured (t _a in FIG. ₂₎ , At least the thickness (height) signal of the food 10

Then, the food 10 on the transport mechanism 20 is disposed between the upper electrode 7a and the lower electrode 7b of the resonance unit 40 (arrangement step).

At about the same time as or before the placement step, the computer 90 that has received the above signal controls the displacement mechanism 30 through the control unit 35 based on the thickness (height) of the food 10 measured in advance. I do. Specifically, the control unit 35 controls the displacement mechanism 30 so that the thickness of the air layer (t _{2 in} FIG. 2) is substantially constant as a predetermined thickness (for example, 5 mm to 50 mm) in the present embodiment. (The lower electrode 7b) and the upper electrode 7a are displaced in a direction of relatively approaching or separating (a displacement step (an example of a correction step; the same applies hereinafter)).

As a result, even if a plurality of foods 10 having irregular shapes and / or sizes are inspected, the thickness of the air layer (t _{2 in} FIG. ₂ ) for each food 10 is substantially constant. The displacement step is for reducing the influence of a change in the electric capacity of the air layer between the upper electrode 7a and the food 10 when the food 10 is disposed between the upper electrode 7a and the lower electrode 7b. It can serve as a correction step for performing correction.

In the present embodiment and other modified examples described later, the food 10 moves continuously on the transport mechanism 20 without stopping between the upper electrode 7a and the lower electrode 7b. Passing through the gap is also included in being "disposed" between the upper electrode 7a and the lower electrode 7b.

In this embodiment, even if the shapes and / or sizes of the foods 10 to be inspected are different from each other due to a part of the configuration of the food inspection system 900 and each of the above-described steps, or water and lipids Even when the food 10 containing both (oil) and the food 10 is to be inspected, the state of the food can be inspected with higher accuracy than before.

(Modification (1) of Second Embodiment)
Next, a modified example of the speed measurement step shown in (S2) described in the second embodiment will be described.

Regarding this modification, a modification using the upper electrode 7a and the lower electrode 7b of the resonance unit 40 instead of the above-described speed / time measuring means 70 can be adopted. According to this example, since it is not necessary to use the speed / time measuring means 70, simplification of the food inspection system 900 and / or reduction of equipment costs can be realized.

Specifically, the above-described second AC signal, which changes when the food 10 moving on the transport mechanism 20 at a constant speed passes between the upper electrode 7a and the lower electrode 7b of the resonance unit 40, Measuring and analyzing the time variation of the signal strength, center frequency, and / or bandwidth of the resonance spectral characteristic based on. By analyzing the time change (time trace) of the signal strength, the center frequency, and / or the bandwidth, the time until the food 10 passes between the

electrodes

7a and 7b, and the length of the food 10 (more To be precise, the length in the moving direction of the food item 10. In this modification, the "effective length" is derived. In this modification, the “effective length” substantially corresponds to the electric capacity of the food 10, and thus to the signal strength, the center frequency, and / or the bandwidth of the food inspection apparatus 100. Will contribute (in other words, influence).

As a result, the previously measured
The thickness (height) of the food 10 and
When approximated to a rectangle obtained by multiplying the effective length of the food 10 by a predetermined width (constant), or an ellipse having the length and the width as a major radius and a minor radius (or vice versa), respectively. Approximate value of the area of food 10 calculated when approximated (in other words, "effective area")
, The effective area of the air layer between the upper electrode 7a and the food 10 is determined. As a result, from the effective area and the thickness of the air layer (t _{2 in} FIG. 2), the electric capacity of the air layer (more precisely, “approximate value of electric capacity”; ) Can be derived.

(Modification (2) of Second Embodiment)
In this modification, only the steps (S1) and (S2) of the food inspection system 900 are employed.

Specifically, two signals shown in the following (z1) and (z2) are output to the computer 90.
(Z1) as shown in FIG. 2, to rest on the transport mechanism 20, or by the transport mechanism 20 the thickness of the food 10 in the upper moving (height) instrument 50 was measured (t _a in FIG. ₂₎ A signal of at least the thickness (height) of the food 10 (z2) With respect to the food 10 moving at a constant speed on the transport mechanism 20, a certain position (the electrodes 7a, a velocity (V _a in FIG. ₂₎ passing through the containing position between 7b), from the tip of the food 10 to the rear end is due to velocity and time measuring means 70 for measuring the time for passing through the position of at least the food 10 Signal of the speed and the time of

At substantially the same time as or before the placement step, the computer 90 that has received the above-described signal, based on the thickness (height) of the food 10 measured in advance, similarly to the second embodiment, A displacement step of controlling the displacement mechanism 30 through the control unit 35 is performed.

As a result, even if a plurality of foods 10 having irregular shapes and / or sizes are inspected, the thickness of the air layer (t _{2 in} FIG. ₂ ) for each food 10 is substantially constant.

Further, in this modification, a correction step based on the signal of (z2) is performed.

Specifically, first, when approximating a rectangle obtained by multiplying the length of the food 10 derived from the speed and the time of the food 10 measured in advance and a predetermined width (constant), or The approximate value of the area of the food 10 calculated when the length and the width are approximated to an ellipse having a major radius and a minor radius (or vice versa), respectively (hereinafter, also referred to as “calculated area”) is: It is calculated by calculation means carried by the computer 90.

By the above-described calculating means, the computer 90 calculates
The thickness (height) of the food 10 (t _{a in} FIG. 2), and
Based on the calculated area of the food 10, the calculated area of the air layer between the upper electrode 7 a and the food 10 (to match the calculated area of the food 10) is determined. As a result, the electric capacity of the air layer can be derived from the calculated area and the thickness of the air layer (t _{2 in} FIG. ₂ ).

As a result, in this modified example, even if the shapes and / or sizes of the foods 10 to be inspected are different from each other due to a part of the configuration of the food inspection system 900 and the respective steps described above, or Even when the food 10 containing both water and lipid (oil) is to be inspected, the state of the food can be inspected with higher accuracy than in the second embodiment.

(Modification (3) of Second Embodiment)
In this modification, only the steps (S1), (S2), and (S4) of the food inspection system 900 are employed.

Specifically, two signals shown in the following (z1) to (z3) are output to the computer 90.
(Z1) as shown in FIG. 2, to rest on the transport mechanism 20, or by the transport mechanism 20 the thickness of the food 10 in the upper moving (height) instrument 50 was measured (t _a in FIG. ₂₎ A signal of at least the thickness (height) of the food 10 (z2) With respect to the food 10 moving at a constant speed on the transport mechanism 20, a certain position (the electrodes 7a, a velocity (V _a in FIG. ₂₎ passing through the containing position between 7b), from the tip of the food 10 to the rear end is due to velocity and time measuring means 70 for measuring the time for passing through the position of at least the food 10 (Z3) At least the weight signal of the food 10 by the weighing unit 80 for measuring the weight of the food 10

{Furthermore, in this modification, the correction step based on the signal (z2) and the correction step based on the signal (z3) described in the modification (1) of the second embodiment are performed.

Specifically, assuming that the density of the food 10 is constant, it is measured in advance,
Weight of food 10,
The thickness (height) of the food 10 (t _{a in} FIG. 2), and
Since the width of the food 10 is derived based on the length of the food 10 derived from the speed and the time of the food 10, the calculation area of the food 10 is calculated by the following calculation means carried by the computer 90. You.

Note that, in this modification, if the “effective length” in the modification (1) of the second embodiment is adopted as the length of the food 10,
Weight of food 10,
The thickness of the food 10 (height) _(t a in FIG. 2), and,
The “effective width” of the food 10 is derived based on the effective length of the food 10.

As a result, the effective area of the air layer between the upper electrode 7a and the food 10 (to match the effective area of the food 10) is determined, and the calculated area is calculated by the following calculation means carried by the computer 90. , And the thickness of the air layer (t _{2 in} FIG. 2), the electric capacity of the air layer can be derived.

The “effective width” is the “width” in a direction orthogonal to the “effective length”. In this case, the “effective width” substantially contributes to the electric capacity of the food 10 and thus to the value of the signal strength, the center frequency, and / or the bandwidth in the food inspection apparatus 100 (in other words, Affect).

(Modification (4) of Second Embodiment)
In the present modification, only the steps (S1), (S2), and (S3) of the food inspection system 900 are employed.

Specifically, two signals shown in the following (z1) and (z4) are output to the computer 90.
(Z1) as shown in FIG. 2, to rest on the transport mechanism 20, or by the transport mechanism 20 the thickness of the food 10 in the upper moving (height) instrument 50 was measured (t _a in FIG. ₂₎ At least the signal of the thickness (height) of the food 10 (z4) for measuring the length (L _{a in} FIG. 2) in plan view by the imaging means 60 for imaging at least the outer shape of the food 10 on the transport mechanism 20. Image signal

Furthermore, in this modification, a correction step based on the signal of (z4) is performed.

Specifically, first, when approximating a rectangle obtained by multiplying the length of the food 10 measured in advance and a predetermined width (constant), or the length and the width, the major radius and the minor radius are respectively used. The calculation area of the food 10 calculated when the ellipse is approximated (or vice versa) is calculated by the calculation means of the computer 90.

By the above-described calculating means, the computer 90 calculates
The thickness (height) of the food 10 (t _{a in} FIG. 2), and
Based on the approximate value of the area of the food 10, the capacitance of the food 10 disposed between the upper electrode 7a and the lower electrode 7b can be derived.

As still another modified example (1) of this modified example, only the steps (S1), (S2), and (S3) of the food inspection system 900 are employed to Outputting an image signal to the computer 90 for measuring the length (L _{a in} FIG. 2) and the width (W _{a in} FIG. 2) in plan view by the imaging unit 60 for imaging the image 10 may be adopted. In this case, not only the length (L _{a in} FIG. 2) but also the width (W _{a in} FIG. 2) of the food 10 can be obtained by the imaging unit 60. Therefore, the modification (4) of the second embodiment of the present invention can be obtained. The accuracy of the inspection can be improved as compared with the case of (1).

In addition, as still another modified example (2) of this modified example, only the steps (S1), (S2), and (S3) of the food inspection system 900 are employed to Outputting an image signal for directly measuring the area of the food 10 in a plan view to the computer 90 by the imaging means 60 for imaging the food 10 can also be adopted. In this case, since information on the area of the food 10 can be obtained by the imaging unit 60, the accuracy of the inspection can be higher than in the modification (4) of the second embodiment.

<Third embodiment>
The food inspection device 200 of the present embodiment is the same as the food inspection device 100 except that the food inspection device 200 of the first embodiment does not include the displacement mechanism 30 and the control unit 35 provided in the food inspection device 100 of the first embodiment. Therefore, description overlapping with the first embodiment may be omitted.

FIG. 3 is a configuration diagram of the food inspection device 200 of the present embodiment.

In this embodiment, since the displacement mechanism 30 of the first embodiment is not provided, the upper electrode 7a and / or the lower electrode 7b cannot be moved up and down. Therefore, the thickness of the air layer existing between the food 10 disposed between the

electrodes

7a and 7b and the upper electrode 7a (corresponding to the “second thickness”. This embodiment and other embodiments (modifications) 3) t ′ ₂ ) in FIG. 3 will be different for each food 10 having a different thickness (height). As a result, the electric capacity of the air layer changes according to the change in the thickness of the air layer.

However, in the present embodiment, the displacement mechanism 30 uses the reference center frequency and / or the reference bandwidth of the reference food when the second thickness is varied, which is measured in advance, as described below. Even without this, for example, a correction for reducing the effect of a change in the electric capacity of the air layer between the upper electrode 7a and the food 10 can be performed.

Hereinafter, when the food 10 is disposed between the upper electrode 7a and the lower electrode 7b, for example, to reduce the influence of a change in the electric capacity of the air layer between the upper electrode 7a and the food 10, A typical correction means and a correction process will be described.

First, the present inventors use the food inspection apparatus 200 of the present embodiment to compare the food 10 to be inspected with the reference center frequency of the reference food when the second thickness is different, which is to be compared. And / or a reference bandwidth was obtained.

FIG. 5 shows the thickness of the air layer between the upper electrode 7a and the food 10 (t ′ _{2 in} FIG. 3) for fish (more specifically, salmon) as an example of a fully thawed food. 6 is a graph showing the relationship between the frequency and the center frequency. FIG. 6 shows the thickness of the air layer between the upper electrode 7a and the food 10 (t ′ in FIG. 3) for fish (more specifically, salmon) as an example of a fully thawed food. ₂ ) is a graph showing the relationship between the bandwidth and the bandwidth.

As shown in FIG. 3, with the change in distance t _'2, the center frequency of the thawed food is seen to fluctuate. For example, by the distance t _'2 changes from 20mm to 25 mm, the center frequency was confirmed to about 25kHz also varies. Similarly, as shown in FIG. 4, with the change in distance t _'2, the bandwidth of uncompressed foods seen to vary. For example, by the distance t _'2 changes from 20mm to 25 mm, the center frequency was confirmed that vary 2kHz or more.

Here, an example of the influence on the inspection result due to the fluctuation of the electric capacity of the air layer will be described. 7, as a reference example, is a graph showing the respective resonance spectrum during freezing (solid line) and during decompression (dotted line) when the value of t ₂ is 30 mm. In the example shown in FIG. 7, the thickness of the air layer existing between the food to be inspected and the electrode is 30 mm. In FIG. 7, the vertical axis of each resonance spectrum at the time of freezing (solid line) and at the time of thawing (dotted line) is standardized for easy viewing. In addition, on the vertical axis in FIG. 7, the degree of resonance intensity is represented as a reflection intensity (the unit is an arbitrary unit, abbreviated as “au”).

As shown in FIG. 7, the difference (Δd in FIG. 7) between the center frequency at the time of freezing (−17.3 ° C.) and the center frequency at the time of thawing (1.2 ° C.) is about 46 kHz, which corresponds to It was confirmed that the difference between the bandwidths was about 37 kHz.

Therefore, in an example of the change between the frozen state and the thawed state, considering that the difference in the center frequency is about 46 kHz and the corresponding difference in the bandwidth is about 37 kHz, the change in the distance of t ′ ₂ is the center. The effects on frequency and bandwidth cannot be ignored.

Therefore, the present inventors adopted the results obtained from FIGS. 5 and 6 as the reference center frequency and the reference bandwidth of the reference food when the second thickness was varied, respectively. In addition, as one of the modified examples of the present embodiment, instead of the results obtained from FIGS. 5 and 6, among the foods 10 to be measured, the food 10 that is first inspected is used as the reference food. Doing so is also a preferred embodiment.

Regarding the reference center frequency and the reference bandwidth, it is preferable that the food inspection apparatus 200 further includes a recording unit or a database, and that the reference center frequency and the reference bandwidth be recorded in the recording unit or the database. It is an aspect. For example, in order to compare the center frequency and / or the bandwidth of the food 10 to be inspected, a recording unit typified by a hard disk drive provided in the computer 90, or the computer 90 electrically or electronically or via a communication unit. The reference center frequency and the reference bandwidth can be temporarily or permanently stored in a recording means that can be connected to the computer.

If the food inspection device 200 having the above-described configuration is used, the center frequency and the bandwidth of the resonance unit 40 are measured, and the measurement result is compared with the reference center frequency and the reference bandwidth of the reference food, so that the upper electrode 7a It is possible to grasp the state (for example, the state of freezing / thawing) of the food 10 disposed between the food 10 and the lower electrode 7b.

More specifically, first, in the food inspection method according to the present embodiment, the thickness (height) (corresponding to the “first thickness”; the same applies hereinafter) by a known measuring unit (t in FIG. 3). An arrangement step of disposing the food 10 to be inspected by the food inspection device 200, for which ₁ ) is measured, between the upper electrode 7a and the lower electrode 7b in the resonance section 40 is performed.

Based on the value of the thickness (height) (t _{1 in} FIG. 3) of the food 10 obtained by pre-measurement after the food 10 is placed, a computer serving as a calculating unit together with the measurement unit. 90 calculates the thickness of the air layer between the upper electrode 7a and the food 10 (corresponding to the “second thickness”; the same applies hereinafter) (t ′ _{2 in} FIG. 3).

と同時に Simultaneously with or before and after the calculation of the thickness of the air layer described above, the food inspection device 200 measures a center frequency and / or a bandwidth derived from a resonance spectrum characteristic of the food 10 to be inspected.

Thereafter, the computer 90 compares the center frequency and / or the bandwidth with respect to the following (1) and (2).
(1) Based on the first thickness of each food 10 to be inspected, the center frequency and / or band calculated as one of the elements based on the electric capacity based on the second thickness of the air layer for each food 10 Width (2) Reference center frequency and / or reference bandwidth corresponding to the thickness of the reference air layer between the upper electrode 7a and the reference food obtained from FIG. 5 and / or FIG.

In the present embodiment, by the above comparison is made, the thickness of the air layer between the upper electrode 7a and food 10 correction step based on the (t _'2 in FIG. ₃₎ is performed by the computer 90.

For example, to explain the center frequency, a reference center frequency of the reference food obtained from FIG. 5 corresponding to the thickness of the air layer (t ′ _{2 in} FIG. 3) is derived. For example, if the value of t ′ ₂ is 15 mm, a reference center frequency of about 1.950 MHz is derived.

Therefore, even if the shapes and / or sizes of the individual foods 10 to be inspected are not uniform, a calculation step (an example of a correction step) for temporarily adjusting the value of t ′ ₂ to 45 mm for each food 10 is assumed. ) Is performed by the computer 90.

Indeed 'by adopting the example ₂ values were 15 mm, t' t as measured food 10 and about 1.950MHz when the value of ₂ is 15 mm, t _'2 values at 45mm The computer 90 performs a calculation step (an example of a correction step) of adding about 0.150 MHz, which is a difference from about 2.100 MHz, which is a reference center frequency at a certain time, to the measured center frequency of the food 10. .

結果 As a result, when the food 10 is disposed between the

electrodes

7a and 7b, the effect of a change in the electric capacity of the air layer between the upper electrode 7a and the food 10 can be reduced.

Similarly, a calculation process (an example of a correction process) for correcting the measured bandwidth of the food 10 is performed for the bandwidth as described above.

<Fourth embodiment>
The food inspection system 920 of the present embodiment is the same as the food inspection device 900 except that the food inspection system 900 of the second embodiment does not include the displacement mechanism 30 and the control unit 35 provided in the food inspection system 900 of the second embodiment. Therefore, description overlapping with the first embodiment or the second embodiment and its modified example may be omitted.

FIG. 4 is a configuration diagram of the food inspection system 920 of the present embodiment including the food inspection device 200.

Similarly to the second embodiment and its modified example, the food inspection system 920 of the present embodiment uses the transport mechanism 20 typified by a known belt conveyor and moves from the left side to the right side of FIG. The food 10 is moved (in the direction P in FIG. 4). Further, in the process of moving the food item 10, the food inspection system 920 of the present embodiment performs some or all of the following steps described in (S1) to (S4) of the second embodiment. Can be.
(S1) The thickness (height) of the food 10 (corresponding to “first thickness”; the same applies hereinafter) (t ′ _{a in} FIG. 4) is measured, and at least the thickness (height) of the food 10 is measured. Thickness (height) measuring side process using a measuring instrument (for example, a known laser distance meter) 50 for outputting a signal (S2) A specific position of the food 10 moving at a constant speed is determined. A speed / time measuring unit (for example, a known speedometer or photoelectric sensor) 70 that measures the passing speed (V _{a in} FIG. 4) and the time from the front end to the rear end of the food 10 passing the position is used. Speed measurement step used (S3) At least the outer shape of the food 10 is imaged, and an image signal for measuring at least the length (L _{a in} FIG. 4) and the width (W _{a in} FIG. 4) in plan view is output. (For example, a digital camera equipped with a known image sensor) 0 was used, by measuring the weight of the imaging step (S4) food 10, using the weighing unit 80 for outputting a weight signal of at least the food 10, weighing process

As in the second embodiment and its modified example, which describe the typical embodiment and its modified example in which a part or all of the specific steps (S1) to (S4) are performed, the "thickness of food 10" (Height) "," effective length "," effective area "," calculated area "," effective width ", and / or" directly measured area "are measured, or The calculation process (an example of the correction process) calculated by the calculation device (an example of the correction device) is performed by the computer 90.

Above measurement results, and the calculating means (calculating step), (can be calculated by the thickness t ₁ of the food 10 is determined) the thickness of the air layer correction step based on the (t _'2 in FIG. _3), the computer 90 Done by

As a result, in the present modification, even if the shapes and / or sizes of the foods 10 to be inspected are different from each other due to a part of the configuration of the food inspection system 920 and the respective steps described above, or Even when the food 10 containing both water and lipid (oil) is to be inspected, the state of the food can be inspected more accurately than in the third embodiment.

とおり As described above, the disclosure of each of the above-described embodiments has been described for describing the embodiments, and is not intended to limit the present invention. In addition, modifications that fall within the scope of the present invention, including other combinations of the embodiments, are also included in the claims.

The one food inspection device and one food inspection method of the present invention are extremely useful in current and future industries dealing with food or in industries performing food inspection.

Claims

A resonance unit including a pair of electrodes and a coil,
A transmitting unit that generates a first AC signal with respect to the resonance unit;
When a food is placed between the electrodes, the signal comprises an AC signal reflected on the resonance section, an AC signal transmitted through the resonance section, an AC signal including a current flowing through the resonance section, and a voltage generated on the resonance section. A receiving unit that receives at least one type of second AC signal selected from a group of AC signals;
From the group of the center frequency of the resonance spectrum characteristic based on the second AC signal, the bandwidth of the resonance spectrum characteristic based on the second AC signal, and the signal intensity of a specific frequency in the resonance spectrum characteristic based on the second AC signal A measuring unit for measuring at least one selected,
A correction unit that performs correction for reducing the influence of the change in the capacitance of the air layer between the electrode and the food,
Food inspection equipment.
The correction means,
An arrangement unit for arranging the food,
A displacement mechanism that displaces the disposition portion and the electrode in a direction to relatively approach or separate while disposing the disposition portion facing the electrode,
When the food is disposed between the electrodes, the second thickness of the air layer for each food is made substantially constant based on the first thickness of the food to be inspected previously measured for each food. And a control unit that controls the displacement mechanism,
The food inspection device according to claim 1.
The correction means,
The capacitance based on the second thickness of the air layer for each food when the food is arranged between the electrodes based on the first thickness of the food to be inspected measured in advance based on the first thickness of each food. The center frequency and / or the bandwidth calculated as one of the elements, the thickness of the reference air layer between the electrode and the reference food when the reference food is disposed between the electrodes. And calculating means for calculating by comparing with a reference center frequency and / or a reference bandwidth corresponding to the
The food inspection device according to claim 1.
The correction unit further includes a calculation unit that calculates an effective area or a calculated area for each food based on the effective length or the length of each food measured in advance,
The food inspection device according to claim 2.
The correction unit further includes a calculation unit that calculates an effective area or a calculated area for each food based on the effective width or the width of each food measured in advance.
The food inspection device according to claim 4.
The calculating means further calculates an effective area or a calculated area for each food, based on an effective length for each food or a length for each food measured in advance.
The food inspection device according to claim 3.
The calculating means further calculates an effective area or a calculated area for each food, based on an effective width for each food or a width for each food measured in advance.
The food inspection device according to claim 6.
Further comprising imaging means for imaging at least the outer shape of the food,
The effective length or the length, the effective width or the width, and / or the effective area or the calculated area for each food is measured in advance using the imaging unit.
The food inspection device according to claim 5.
Further comprising imaging means for imaging at least the outer shape of the food,
The effective length or the length, the effective width or the width, and / or the effective area or the calculated area for each food is measured in advance using the imaging unit.
The food inspection device according to claim 7.
An arrangement step of arranging food between the electrodes, of the resonance section including a pair of electrodes and a coil,
When the food is disposed between the electrodes, a correction step of performing a correction to reduce the effect of a change in the capacitance of the air layer between the electrodes and the food,
A transmitting step of generating a first AC signal to the resonance unit;
When the food is disposed between the electrodes, an AC signal reflected on the resonance unit, an AC signal transmitted through the resonance unit, an AC signal including a current flowing through the resonance unit, and a voltage generated on the resonance unit Receiving at least one type of second AC signal selected from the group of AC signals:
From the group of the center frequency of the resonance spectrum characteristic based on the second AC signal, the bandwidth of the resonance spectrum characteristic based on the second AC signal, and the signal intensity of a specific frequency in the resonance spectrum characteristic based on the second AC signal Measuring at least one selected, and
Food inspection method.
The correcting step includes:
When the food is disposed between the electrodes, the second thickness of the air layer for each food is made substantially constant based on the first thickness of the food to be inspected previously measured for each food. As described above, including a displacement step of giving a displacement in a direction to relatively approach or separate the placement portion and the electrode while facing the electrode placement portion for placing the food,
The food inspection method according to claim 10.
The correcting step includes:
The capacitance based on the second thickness of the air layer for each food when the food is arranged between the electrodes based on the first thickness of the food to be inspected measured in advance based on the first thickness of each food. The center frequency and / or the bandwidth calculated as one of the elements, the thickness of the reference air layer between the electrode and the reference food when the reference food is disposed between the electrodes. Including a calculation step of calculating by comparing with the reference center frequency and / or reference bandwidth corresponding to
The food inspection method according to claim 10.