JP2021067481A - Timber inspection device - Google Patents

Abstract

To provide a timber inspection device capable of inspecting the distribution of the impregnation amount of a chemical in one timber.SOLUTION: Sandwiching a timber 1 impregnated with a noncombustible agent, microwave transmitting antennas 2a, 2b, 2c, 2d, 2e and receiving antennas 3a 3b, 3c, 3d, 3e are installed facing each other, with a microwave transmitting circuit 5 connected to the transmitting antenna and a microwave receiving circuit 6 connected to the receiving antenna. An amount of incombustible impregnated in the timber 1 is inspected by detecting an amplitude and phase of microwave being output from the transmitting antenna, transmitted through the timber 1 and input to the receiving antenna, calculating a distribution of the relative permittivity of the timber 1 from the amplitude and phase and using the relationship between the amount of incombustible impregnated and the permittivity of timber obtained in advance.SELECTED DRAWING: Figure 1

Description

The present invention relates to a wood inspection device impregnated with a chemical and inspects the amount of the chemical impregnated in the wood.

For special buildings such as public buildings, it is necessary to use fireproof materials stipulated in the Building Standards Act. When wood is used in a special building, the wood is impregnated with a flame-retardant chemical (hereinafter referred to as a non-flammable agent) in order to satisfy the above criteria as a fireproof material to impart flame retardancy. Examples of such a method for producing non-combustible wood are described in Patent Documents 1 and 2. Conventionally, the content of non-combustible agent in wood is grasped and controlled by the weight difference of wood before and after impregnation as described in Patent Documents 1 and 2.

JP 2003-21142 JP-A-2018-188552

Usually, in the produced non-combustible wood, the impregnation amount of the non-combustible agent often varies within one wood, and the part where the impregnation amount is small may not satisfy the above-mentioned standard as a fireproof material. However, in the conventional method of inspecting the impregnation amount by the weight difference before and after impregnation, the impregnation amount of the noncombustible agent in one non-combustible wood is inspected by measuring the weight difference before and after impregnation of one target wood as a whole. It was not possible to inspect the variation, that is, the distribution of the impregnation amount. In addition, wood for various purposes may be impregnated with a drug such as a preservative in addition to a non-combustible agent to improve environmental resistance. Even in such a case, it is necessary to inspect the distribution of the impregnation amount of the chemical in order to suppress the variation in the performance in the wood.

Therefore, the present invention has been made to solve such a problem, and an object of the present invention is to provide a wood inspection apparatus capable of inspecting the distribution of the impregnation amount of a chemical in one wood.

From the first aspect, the wood inspection apparatus of the present invention is an inspection apparatus for wood impregnated with a chemical, and is a microwave transmitting antenna and a receiving antenna installed opposite to each other with the wood sandwiched therein, and the transmitting antenna. It has a microwave transmitting circuit connected to the receiving antenna and a microwave receiving circuit connected to the receiving antenna, and the amplitude of the microwave transmitted from the transmitting antenna, transmitted through the wood, and input to the receiving antenna. The phase is detected, the specific dielectric constant of the wood is calculated from the detected microwave amplitude and phase, and the relationship between the specific dielectric constant, the preliminarily obtained impregnation amount of the chemical, and the specific dielectric constant. And, it is characterized in that the impregnation amount of the chemical is inspected in the wood.

In the present invention, as described above, the microwave transmitting antenna and the receiving antenna are installed with the wood as the object to be measured sandwiched between them, and the microwave transmitted from the transmitting antenna, passes through the wood, and is input to the receiving antenna. Detects amplitude and phase. As a result, the relative permittivity of the region through which the microwave of the wood passes is calculated. Since the wood targeted by the present invention usually has two surfaces that are substantially parallel, that is, a front surface and a back surface, the incident microwave is multiple-reflected and output between the front surface and the back surface. In this case, if it is noted that the relative permittivity of wood is close to 1, the relative permittivity of wood can be calculated by an approximate calculation ignoring multiple reflections. On the other hand, by using a calculation formula that considers multiple reflections, the relative permittivity of wood in the region through which microwaves pass can be obtained more accurately.

In the present invention, the relationship between the amount of chemicals impregnated in wood and the relative permittivity of the wood is determined in advance, and the relationship is used to determine the amount of chemicals impregnated in wood based on the measured relative permittivity. It is for inspection. In this case, for example, a method in which a large number of wood samples to be measured having a small area in which the impregnation amount of the chemical is changed is prepared, and the impregnation amount of the chemical in these wood samples is measured by the weight difference before and after the conventional impregnation, or X. It is grasped by using a method of measuring from the change in the amount of wire transmission, and the relative permittivity of those wood samples is measured by the above-mentioned method using the microwave of the present invention to determine the amount of chemicals impregnated in the wood. The relationship with the relative permittivity can be obtained. Using the relationship between the impregnation amount of the chemical and the relative permittivity obtained in this way, whether or not the value of the relative permittivity of the measured portion of the wood is equal to or more than the value corresponding to the required amount of the impregnation of the chemical, etc. Can be inspected.

As described above, in the present invention, the impregnation amount of the chemical in the portion of the wood to be measured through which the microwave is transmitted can be inspected. Therefore, by measuring while moving the wood, the chemical in one wood can be inspected. It is possible to inspect the distribution of the impregnation amount. For example, when the wood to be measured is elongated, the distribution of the impregnation amount of the chemical in the length direction can be inspected by moving the wood in the length direction. Further, when the area of the wood to be measured is large, the two-dimensional distribution of the impregnation amount of the chemical can be inspected by moving the wood two-dimensionally.

From the second aspect, the present invention relates to the wood inspection device according to the first aspect, wherein the plurality of the transmitting antennas and the plurality of the transmitting antennas are arranged so as to face each other with the wood interposed therebetween. Having a receiving antenna and a display device that measures the two-dimensional distribution of the relative permittivity of the wood by moving the wood in one direction and performing the detection, and displays the two-dimensional distribution. It is a feature.

In the invention of this aspect, the wood is moved in one direction by arranging the plurality of transmitting antennas and the plurality of receiving antennas facing each other with the wood sandwiched at intervals so that the resolution of the distribution for measurement can be achieved. The two-dimensional distribution of the impregnation amount of the drug can be inspected even when the mixture is allowed to be used. Further, by providing a display device for displaying the two-dimensional distribution of the measured relative permittivity, the two-dimensional distribution can be easily grasped visually.

From the third aspect, in the wood inspection apparatus of the second aspect, the plurality of transmitting antennas and the plurality of receiving antennas are different from each other with respect to the direction orthogonal to the moving direction of the wood. It is characterized in that it is arranged at a position and has a switch between the plurality of transmitting antennas and the microwave transmitting circuit, and the detection is performed while sequentially switching the plurality of transmitting antennas by the switch.

In the invention of this aspect, for example, a plurality of pairs of transmitting antennas and receiving antennas are arranged side by side in the width direction of the wood to be measured, and the wood to be measured is moved in the length direction of the wood to be measured to move the entire wood. The two-dimensional distribution of the relative permittivity can be measured. Further, a switch is arranged between the transmitting antenna and the microwave transmission circuit, the transmitting antenna corresponding to the measurement site is connected to the microwave transmission circuit for detection by the switch, and the measurement site is sequentially moved in the width direction by the switch. By performing detection while switching, detection can be performed using one microwave transmission circuit. In this case, a switch or a distributor may be arranged between the receiving antenna and the microwave receiving circuit. This enables detection using one microwave receiving circuit. Further, in the present invention, a distributor may be arranged between the transmitting antenna and the microwave transmitting circuit, and a switch may be arranged between the receiving antenna and the microwave receiving circuit.

From the fourth aspect, the present invention performs the detection using microwaves having a plurality of frequencies in the wood inspection apparatus according to the first to third aspects, and the ratio is based on the plurality of data obtained by the detection. It is characterized in that the dielectric constant is calculated.

In the present invention, when calculating the relative permittivity of wood, it is possible to calculate the relative permittivity even if a single microwave frequency is used, but the measurement error may become large due to the influence of noise or the like. is there. In the invention of this aspect, in order to reduce the measurement error due to such noise and the like, the frequency is swept and the detection is performed using the frequencies of a plurality of microwaves, and the relative permittivity of the wood is used using the plurality of data. Is calculated. By calculating the optimum value by fitting analysis from the detection data of a plurality of frequencies, it is possible to calculate the relative permittivity more accurately.

From the fifth aspect, the present invention presents the relative permittivity of the wood before impregnation with the chemical, or the two-dimensional distribution of the relative permittivity, that is, the initial relative permittivity, in the wood inspection apparatus of the first to fourth aspects. The rate or initial relative permittivity distribution is measured in advance, and the difference between the initial relative permittivity or the initial relative permittivity distribution and the two-dimensional distribution of the relative permittivity or the relative permittivity of the wood impregnated with a chemical agent. It is characterized by having a means for inspecting the impregnation amount of the drug by the difference.

The wood to be measured may have some individual differences in its relative permittivity, and sufficient measurement accuracy can be obtained by using only the relationship between the amount of chemical impregnation obtained in advance from the wood sample and the relative permittivity of wood. It may not be possible. In the invention of this viewpoint, by providing a means for calculating the difference in the relative permittivity before and after impregnation with the chemical, even if there is an individual difference in the relative permittivity of wood as described above, the impregnation amount distribution can be inspected more accurately. can do.

From the sixth aspect, the present invention is characterized in that, in the wood inspection apparatus of the first to fifth aspects, the transmitting antenna and the receiving antenna are horn antennas. In experiments and studies using some of the inventors for microwaves, it was confirmed that the horn antenna is suitable for the purpose of the present invention.

As described above, according to the wood inspection apparatus of the present invention, it is possible to inspect the distribution of the impregnation amount of the chemical in one wood.

The schematic block diagram of the wood inspection apparatus which concerns on Example 1. FIG. The figure which shows the state of the microwave which passes through the wood by multiple reflections. The perspective view which shows an example of the arrangement of the transmitting antenna and the receiving antenna in Example 1. FIG. The figure which shows an example of the relationship between the phase and the frequency of the microwave which passes through wood. The figure which shows an example of the result of having measured the relationship between the impregnation amount of the noncombustible agent of wood and the change amount of a relative permittivity in Example 2. The figure which shows an example of the measurement result of the two-dimensional distribution of the change amount of the relative permittivity of wood. The figure which shows an example of the measurement result of the two-dimensional distribution of the change amount of the relative permittivity of wood.

Hereinafter, the wood inspection apparatus of the present invention will be described in detail with reference to the drawings. In the description of the drawings, the same elements are designated by the same reference numerals, and the duplicated description will be omitted.

FIG. 1 is a schematic configuration diagram of the wood inspection device 20 according to the first embodiment. In FIG. 1, the wood inspection device 20 of this embodiment is an inspection device for wood 1 impregnated with a non-combustible agent, and has five microwave transmitting antennas 2a, 2b, 2c, 2d, 2e, and the like. It has five microwave receiving antennas 3a, 3b, 3c, 3d, and 3e that are installed opposite to each other with the wood 1 in between. In this embodiment, the transmitting antennas 2a, 2b, 2c, 2d, 2e and the receiving antennas 3a, 3b, 3c, 3d, 3e are configured by using a horn antenna. In FIG. 1, the wood 1 shows a cross-sectional view, and is configured to be moved in the x-axis direction by the wood transport device 4. The five transmitting antennas and the receiving antennas are arranged at different positions with respect to the y-axis direction orthogonal to the x-axis which is the moving direction of the wood 1.

The wood inspection device 20 of this embodiment includes a microwave transmission circuit path 5 that supplies microwaves to the transmission antennas 2a, 2b, 2c, 2d, and 2e, and the front and back surfaces of the wood 1 that are transmitted from the transmission antennas. It is provided with a microwave receiving circuit 6 for detecting microwaves that are multiple-reflected between the antennas, pass through the wood 1, and are input to the receiving antennas 3a, 3b, 3c, 3d, and 3e. The microwave transmission circuit path 5 includes a transmitter 11 that generates a microwave signal of a predetermined frequency and a distributor 12 for distributing a part of the signal to the microwave reception circuit 6, and the microwave reception circuit 6 includes a distributor 12. , A microwave detector 13 and an amplifier 14 that amplifies and outputs the detected signal are provided. The microwave transmission circuit path 5 and the microwave reception circuit 6 are integrally incorporated in the microwave unit 7. The frequency of the microwave used in this embodiment is 22 GHz to 28 GHz, which is optimal for measurement, but the frequency range can be selected within the range of about 8 GHz to 40 GHz.

Further, in this embodiment, the switch 8 is provided between the transmitting antennas 2a, 2b, 2c, 2d, 2e and the microwave transmitting circuit 5, and the receiving antennas 3a, 3b, 3c, 3d, 3e and the microwave receiving are received. A distributor 9 is provided between the circuit 6 and the circuit 6. The switch 8 connects the output of the microwave transmission circuit 5 to any of the transmission antennas 2a, 2b, 2c, 2d, and 2e. When a microwave transmitted through the wood 1 is input to any of the receiving antennas 3a, 3b, 3c, 3d, and 3e facing the connected transmitting antenna, the signal is transmitted to the microwave receiving circuit 6 via the distributor 9. Enter in. In this embodiment, the transmitting antenna unit 16 is configured by the transmitting antennas 2a, 2b, 2c, 2d, 2e and the switch 8, and the receiving antenna unit 17 is configured by the receiving antennas 3a, 3b, 3c, 3d, 3e and the distributor 9. doing.

In this embodiment, the microwaves input to the receiving antennas 3a, 3b, 3c, 3d, and 3e are detected and amplified by the microwave receiving circuit 6, and the microwave signal is input to the personal computer 10. In the personal computer 10, the amplitude and phase of the input microwave signal are detected, and the relative permittivity of the portion of the wood 1 through which the microwave has passed is calculated using the amplitude and phase. Further, an encoder pulse is input to the personal computer 10 from the wood transport device 4, and in synchronization with the encoder pulse, a microwave frequency command signal or the like is output to the microwave unit 7 and switched to the switch 8. Output a signal.

By sequentially switching the switch 8 to calculate the relative permittivity distribution of the wood 1 in the y-axis direction at specific x-axis coordinates and sequentially moving the wood 1 in the x-axis direction by the wood transport device 4, the two in the xy direction The dimensional relative permittivity distribution can be obtained. The two-dimensional distribution of the obtained relative permittivity is configured so that it can be displayed on the display unit 15 of the personal computer 10.

Further, in the personal computer 10, the relationship between the impregnation amount of the noncombustible agent and the relative permittivity of the wood 1 is stored in the memory. The relationship between the impregnation amount of the incombustible agent and the relative permittivity is that a large number of wood samples of the same material as the wood 1 having a small area in which the impregnation amount of the incombustible agent is changed are prepared, and the impregnation amount of the incombustible agent in these wood samples is determined. It is a value obtained by measuring using a conventional method of measuring by the weight difference before and after impregnation or a method of measuring from a change in the amount of X-ray transmission. Using this relationship, the personal computer 10 processes so as to display on the display unit 15 whether or not the relative permittivity of the measurement portion of wood is equal to or more than the value corresponding to the impregnation amount of the required noncombustible agent. can do. In this case, it is also possible to set the value of the relative permittivity corresponding to the impregnation amount, which is the standard of non-combustible performance, by a keyboard or an external input. With the two-dimensional distribution displayed on the display unit 15, the distribution of the impregnation amount of the noncombustible agent can be easily inspected.

The method of calculating the relative permittivity of wood 1 will be described below. FIG. 2 is a diagram schematically showing a state of microwaves passing through wood 1 by multiple reflection. The incident microwave 21 from the front surface 1a of the wood 1 passes through the wood 1 and is output as it is from the back surface 1b, or is reflected and output several times between the back surface 1b and the front surface 1a, and the combined waves thereof are output. It is a transmitted microwave 22. The intensity of the transmitted microwave 22 is the intensity of the incident microwave 21, its frequency, the speed of light, the reflectance and transmittance when incident on wood 1 from air, and the reflectance and transmittance when incident on wood 1 from wood 1. It can be theoretically expressed using the ratio, the thickness of the wood 1, its relative permittivity, the magnetic transmittance, and the dielectric positive contact. _{The relative permittivity ε r} of wood 1 can be obtained by measuring the intensity of the transmitted microwave 22 using a theoretical formula that takes this multiple reflected wave into consideration.

In FIG. 2, when the relative permittivity ε _r of the wood 1 is small and the reflectance of the microwave is small, the intensity E ₁ of the transmitted microwave 22 is approximated by the equation (1). Here, the intensity of the incident microwave 21 is E ₀ , its frequency is f, the speed of light is c, and the thickness of wood 1 is d. Further, i is an imaginary number, and the term including the imaginary number is a term related to the phase of the microwave.

Even if the formula (1) is used _{, the relative permittivity ε r} of the wood 1 can be obtained by measuring _{the intensity E 1} of the transmitted microwave 22.

FIG. 3 is a perspective view showing an example of the arrangement of the transmitting antennas 2a, 2b, 2c, 2d, 2e and the receiving antennas 3a, 3b, 3c, 3d, 3e in this embodiment. When the antennas are arranged in the y-axis direction with the same x-coordinate, the measurement resolution in the y-axis direction is limited by the size of the opening of the horn antenna. In order to raise the height, the x-coordinates are also shifted so that the openings of the horn antennas may overlap each other in the y-axis direction. By sequentially switching the transmitting antenna with the switch 8, the measurement region of the relative permittivity of the wood 1 sequentially moves to the region 23, the region 24, the region 25, the region 26, and the region 27, and further moves the wood 1 in the x-axis direction. By doing so, a two-dimensional distribution can be obtained.

The basic configuration of the wood inspection device of the second embodiment is the same as that of the first embodiment. However, the wood inspection device of this embodiment has a configuration in which detection is performed using microwaves having a plurality of frequencies, and the relative permittivity of wood 1 is calculated from a plurality of data obtained by these detections. Obtaining the phase and amplitude data of the incident microwave 21 immediately before the wood is inserted between the transmitting antenna and the receiving antenna, and calculating the phase change due to the wood 1 based on the values, the wood 1 The two-dimensional distribution of the relative permittivity before impregnation with the non-combustible agent, that is, the initial relative permittivity distribution is measured in advance, and the initial relative permittivity distribution and the relative permittivity of wood 1 after impregnation with the non-combustible agent are two. The difference is that the means for obtaining the difference from the dimensional distribution and inspecting the impregnation amount of the incombustible agent based on the difference is provided.

FIG. 4 is a diagram showing an example of the relationship between the phase and frequency of microwaves transmitted through wood 1. Although it is possible to calculate the relative permittivity using a single microwave frequency, the measurement error may increase due to the influence of noise and the like. Further, when calculating the phase of a microwave, the absolute value of the phase may be unknown when the amount of change in the phase is 2π or more. Therefore, by sweeping the frequency of the microwave and obtaining the phase for a plurality of frequencies, it is possible to calculate the optimum value by the fitting analysis and calculate the relative permittivity more accurately. For example, in FIG. 4, when the phase changes from φ _{1 to φ 2 when the frequencies are swept from f 1} to f ₂ , the proportional coefficient with respect to the frequency of the phase, that is, the slope of the straight line 28 in FIG. 4 shows the phase of the transmitted microwave. An accurate value can be specified and an accurate relative permittivity ε _r can be obtained.

In microwave devices, the phase and amplitude may drift due to temperature changes and the like. In such a case, the phase and amplitude of the transmitted microwave 22 also drift, and the reference value changes, so that the accurate relative permittivity of the wood 1 cannot be measured. Therefore, in this embodiment, the phase and amplitude data of the incident microwave 21 immediately before the wood is inserted between the transmitting antenna and the receiving antenna is acquired, and the phase change due to the wood 1 is calculated based on the data, and the ratio is calculated. The dielectric constant is calculated.

Further, in this embodiment, in order to further improve the inspection accuracy of the impregnation amount, the relative permittivity distribution of the wood before impregnating the wood 1 with the incombustible agent is measured, and the relative permittivity distribution after the impregnation is used as a reference. Is measured, and the difference in the relative permittivity before and after impregnation with the incombustible agent, that is, the amount of change in the relative permittivity is obtained. As a result, it is possible to eliminate the influence of the variation of the relative permittivity originally possessed by the wood 1 itself depending on the portion, and it is possible to obtain the distribution of the relative permittivity change amount corresponding to the more accurate distribution of the impregnation amount. ..

FIG. 5 is a diagram showing an example of the result of measuring the relationship between the impregnation amount of the noncombustible agent of wood and the relative permittivity in this embodiment. For five types of wood with different morphologies and parts, prepare samples with different impregnation amounts of the incombustible agent, and change the relative permittivity after impregnation with the incombustible agent based on the relative permittivity of the sample before impregnation with the incombustible agent. The result of measuring the quantity is shown. Here, the amount of change in the relative permittivity indicates a value obtained by averaging the measurement data in the entire in-plane for each sample. The impregnation amount value is the impregnation amount of the noncombustible agent per wood sample. From FIG. 5, it can be seen that the amount of change in the relative permittivity increases in proportion to the amount of the incombustible impregnated, and that the slopes of the five types of wood samples are almost the same. The measured value of the relative permittivity ε _r of the wood sample of this example was about 1.5 to 2.3 at a microwave frequency of 22 to 28 GHz.

The two-dimensional distribution of the amount of change in the relative permittivity before and after impregnation of the noncombustible agent in wood was measured by the wood inspection device of this example. 6 and 7 are diagrams showing an example of the measurement results of the two-dimensional distribution of the amount of change in the relative permittivity of two types of wood impregnated with a non-combustible agent under different conditions, and the distribution displayed on the display. Is shown. In FIGS. 6 and 7, in the actual screen, red (R), yellow (Y), green (G), and blue (B) are color-coded in this order according to the amount of change in the relative permittivity. Red (R) is around 0.8 to 1.0 relative permittivity change, yellow (Y) is around 0.7 relative permittivity change, green (G) is around 0.5 relative permittivity change, blue (B) shows values in the vicinity of the relative permittivity change amount of 0.2 to 0.3, respectively. In the wood sample of FIG. 6, the amount of change in the relative permittivity is mainly distributed around 0.2 to 0.5, and in the wood sample of FIG. 7, the amount of change in the relative permittivity is mainly distributed in the vicinity of 0.6 to 1.0. doing. This display allows the inspector to visually recognize the two-dimensional distribution of the impregnation amount corresponding to the relative permittivity in the wood. For example, when the value of the relative permittivity change amount corresponding to the impregnation amount that is the standard of non-combustible performance is around 0.3, it can be recognized that the impregnation amount of the blue portion of the display screen is equal to or less than the reference value.

As described above, it was confirmed that the wood inspection apparatus of the present invention can inspect the distribution of the impregnation amount of the noncombustible agent in one noncombustible wood. In the above embodiment, the case where the chemical to be impregnated in the wood is a non-combustible agent is shown, but even when the chemical is impregnated with another chemical such as a preservative, the impregnation amount and the relative permittivity of the chemical are determined in advance. If the relationship is obtained, it is possible to inspect the distribution of the impregnation amount in the same manner as in the above embodiment.

Needless to say, the present invention is not limited to the above embodiment, and the design can be changed according to the purpose and application. For example, the transmitting antenna and the receiving antenna can be configured by using a microwave antenna other than the horn antenna, for example, a probe antenna. The optimum configuration of the number of transmitting antennas and receiving antennas installed and their arrangement may be selected according to the shape of the wood to be measured and the like.

1 Wood 1a Front surface 1b Back surface 2a, 2b, 2c, 2d, 2e Transmission antenna 3a, 3b, 3c, 3d, 3e Reception antenna 4 Wood transfer device 5 Microwave transmission circuit 6 Microwave reception circuit 7 Microwave unit 8 Switch 9, 12 Distributor
10 Personal computer 11 Transmitter 13 Detector 14 Amplifier 15 Display 16 Transmitter antenna unit 17 Receiving antenna unit 20 Wood inspection device 21 Incident microwave 22 Transmitted microwave 23, 24, 25, 26, 27 Area 28 Straight line

Claims (6)

A chemical-impregnated wood inspection device
It has a microwave transmitting antenna and a receiving antenna installed opposite to each other across the wood, a microwave transmitting circuit connected to the transmitting antenna, and a microwave receiving circuit connected to the receiving antenna.
The amplitude and phase of microwaves transmitted from the transmitting antenna, transmitted through the wood, and input to the receiving antenna are detected.
The relative permittivity of the wood is calculated from the detected microwave amplitude and phase.
A wood inspection apparatus for inspecting the impregnation amount of the chemical in the wood by using the relative permittivity, the impregnation amount of the chemical, and the relationship between the relative permittivity obtained in advance. Having a plurality of the transmitting antennas, the plurality of transmitting antennas sandwiching the wood, and a plurality of the receiving antennas arranged opposite to each other, the wood is moved in one direction to perform the detection. The wood inspection device according to claim 1, further comprising a display device that measures the two-dimensional distribution of the relative permittivity of the wood and displays the two-dimensional distribution. The plurality of transmitting antennas and the plurality of receiving antennas are arranged at different positions with respect to a direction orthogonal to the moving direction of the wood, and are located between the plurality of transmitting antennas and the microwave transmitting circuit. The wood inspection apparatus according to claim 2, further comprising a switch, wherein the detection is performed while sequentially switching the plurality of transmitting antennas by the switch. The invention according to any one of claims 1 to 3, wherein the detection is performed using microwaves having a plurality of frequencies, and the relative permittivity is calculated from a plurality of data obtained by the detection. Wood inspection equipment. The relative permittivity before impregnating the chemical of the wood, or the two-dimensional distribution of the relative permittivity, that is, the initial relative permittivity or the initial relative permittivity distribution is measured in advance, and the initial relative permittivity or the initial relative permittivity is measured. The claim is characterized in that it has a means for obtaining a difference between the distribution and the relative permittivity of the wood impregnated with the chemical or the two-dimensional distribution of the relative permittivity, and inspecting the impregnation amount of the chemical by the difference. The wood inspection apparatus according to any one of 1 to 4. The wood inspection device according to any one of claims 1 to 5, wherein the transmitting antenna and the receiving antenna are horn antennas.

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