JP5268151B2 - Wood moisture content identification device and wood moisture content identification method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To more accurately determine a moisture content without dispersion caused according to the type of wood. <P>SOLUTION: A device for determining the moisture content of wood determines the moisture content of a measurement wood 1 by irradiating the measurement wood 1 with an electromagnetic wave, and receiving the electromagnetic wave through the measurement wood 1. The device includes a transmission antenna 3 for emitting an electromagnetic wave; a reception antenna 4 for receiving a passing electromagnetic wave; and a rotation means 5 that arranges the transmission antenna 3 and the reception antenna 4 to face each other with the measurement wood 1 sandwiched therebetween, and synchronously rotates the transmission antenna 3 and the reception antenna 4 around a propagation direction of the electromagnetic wave as an axis. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a wood moisture content identification apparatus and a wood moisture content identification method for identifying moisture content by irradiating wood or a wooden structure with electromagnetic waves and receiving transmitted electromagnetic waves.

  FIG. 9 is a schematic diagram showing an example of a conventional moisture content identification (measurement) device. The illustrated moisture content identification device includes a transmitter 91 that transmits electromagnetic waves, a receiver 92 that receives electromagnetic waves transmitted from the transmitter 91, and a slit 93a that regulates the measurement region of the electromagnetic waves that have passed through the measured wood 1. And a plane slit plate 93 having the same. The vibration direction (E surface) of the electromagnetic wave from the transmitter 91 is arranged in the longitudinal direction of the measured wood 1 (vertical direction in the case of a raw wood state), that is, in a state substantially parallel to the wood. In this moisture content identification device, when water (dielectric material) contained in the wood to be measured 1 is irradiated with electromagnetic waves, the microwave penetrates into the water and attenuates. The amount of attenuation is calculated by measuring when there is no measured wood 1 and when there is measured wood 1.

  Such a conventional moisture content identification device can obtain sufficient measurement accuracy when the measured wood 1 is a relatively thin plate. However, since electromagnetic waves are reflected on the surface of the measured wood 1 and electromagnetic waves entering the measured wood 1 are reduced, if the measured wood 1 is thick, a sufficient dynamic range cannot be obtained in the measurement. It is difficult to identify the exact moisture content.

  On the other hand, the angle between the vibration direction of the electromagnetic wave and the direction of the wood grain of the measured wood is made obtuse or perpendicular, thereby reducing the electromagnetic waves reflected on the surface of the measured wood, The electromagnetic wave incident inward is made relatively large. As a result, it is possible to leave enough room for incident electromagnetic waves to be attenuated by moisture, and measurement is possible even with thick wood to be measured.

JP 2001-124707 A JP 2000-206058 A

  However, the conventional identification device described above has the following problems.

  The electrical characteristics of wood, particularly the complex permittivity, depends on the angle between the direction of vibration of electromagnetic waves and the direction of scanning of wood. Complex permittivity is expressed by relative permittivity and dielectric loss, and is closely related to the reflection of electromagnetic waves on the surface of wood and the attenuation inside, and reflection and attenuation tend to be different from each other with respect to the complex permittivity. Indicates. The tendency varies depending on the type of wood.

  As described above, even if the angle of the wood or transmitter to be measured is set so that reflection on the surface is minimized, the internal attenuation differs depending on the type of wood. The strength of is different. Therefore, in the conventional method for identifying the moisture content from the transmission intensity obtained at an appropriate angle, a large variation occurs depending on the type of wood. Since this variation may exceed the standard required for quality control of wood, there is a problem of accuracy that it is difficult to apply it especially for the purpose of lumber management in which a grading system is introduced.

  The present invention has been made to solve the above-described problems, and can reduce the variation in the identified moisture content depending on the type of wood, and can be applied to applications requiring high accuracy. It is an object of the present invention to provide an apparatus and method.

In order to achieve the above-mentioned object, the first aspect of the present invention provides a wood moisture content that identifies the moisture content of the wood to be measured by irradiating the wood to be measured with electromagnetic waves and receiving the electromagnetic waves transmitted through the wood to be measured. An identification device, wherein a transmitting antenna that radiates electromagnetic waves, a receiving antenna that receives transmitted electromagnetic waves, and the transmitting antenna and the receiving antenna are arranged so as to sandwich the measured wood, and the transmitting antenna and in synchronization with the receiving antenna have a rotating means for rotating the direction of propagation of the electromagnetic wave as an axis, the propagation direction of the said receiving antenna and said transmitting antenna while irradiating an electromagnetic wave to be measured wood electromagnetic wave Rotate as an axis, receive electromagnetic waves that pass through the measured wood at each rotation angle, and determine the attenuation coefficient and position of the measured wood from the rotation angle dependence of the received intensity. The coefficient was measured, to identify the moisture content of該被measurement timber by using the previously obtained for the comparative timber of the measurement timber of the same kind, the correlation coefficient between the water content and the attenuation coefficient and phase coefficient.

The second aspect of the present invention is a wood moisture content identification device for identifying the moisture content of the wood to be measured by irradiating the wood to be measured with electromagnetic waves and receiving the electromagnetic waves transmitted through the wood to be measured. A plurality of pairs of transmission antennas for irradiating electromagnetic waves and a reception antenna for receiving transmitted electromagnetic waves, each of the plurality of pairs of transmission antennas and reception antennas are arranged to face each other with the measured wood sandwiched therebetween, A pair of transmitting antennas and receiving antennas are arranged at the same rotation angle with the propagation direction of electromagnetic waves as an axis, the plural pairs of transmitting antennas and receiving antennas are arranged in a straight line, and electromagnetic waves are irradiated to the measured wood The wood to be measured is passed between a plurality of pairs of the transmitting antenna and the receiving antenna, and the wood to be measured at each rotation angle with the propagation direction of the electromagnetic wave as an axis. Receiving the electromagnetic wave, and measuring the attenuation coefficient and phase coefficient of the wood to be measured from the dependency of the received intensity on the rotation angle, the moisture content and the attenuation coefficient obtained in advance for the same type of comparative wood as the wood to be measured The moisture content of the wood to be measured is identified using the correlation coefficient with the phase coefficient .

The third aspect of the present invention is a wood moisture content identification method for identifying the moisture content of the wood to be measured by irradiating the wood to be measured with electromagnetic waves and receiving the electromagnetic waves transmitted through the wood to be measured. A transmitting antenna for irradiating electromagnetic waves, a receiving antenna for receiving transmitted electromagnetic waves, and the transmitting antenna and the receiving antenna are arranged so as to sandwich the measured wood, and the transmitting antenna and the receiving antenna are synchronized. Then, using a wood moisture content identification device having a rotating means for rotating about the propagation direction of the electromagnetic wave, the propagation direction of the electromagnetic wave is set between the transmitting antenna and the receiving antenna in a state where the electromagnetic wave is irradiated to the measured wood. It rotates as an axis, receives electromagnetic waves that pass through the measured wood at each rotation angle, and determines the attenuation factor of the measured wood from the rotation angle dependence of the received intensity. The phase coefficient is measured, and the moisture content of the wood to be measured is identified using the correlation coefficient between the moisture content, the attenuation coefficient, and the phase coefficient obtained in advance for the same type of comparative wood as the wood to be measured. And an identification step.
The fourth aspect of the present invention is a wood moisture content identification method for identifying the moisture content of the wood to be measured by irradiating the wood to be measured with electromagnetic waves and receiving the electromagnetic waves transmitted through the wood to be measured. A plurality of pairs of transmission antennas for irradiating electromagnetic waves and a reception antenna for receiving transmitted electromagnetic waves, each of the plurality of pairs of transmission antennas and reception antennas are arranged to face each other with the measured wood sandwiched therebetween, Using the wood moisture content identification device in which a pair of transmitting antennas and receiving antennas are arranged at the same rotation angle about the propagation direction of electromagnetic waves, and the plural pairs of transmitting antennas and receiving antennas are arranged linearly, the measured object With the electromagnetic wave applied to the wood, the wood to be measured is passed between a plurality of pairs of the transmitting antenna and the receiving antenna, and each rotation around the propagation direction of the electromagnetic wave Receiving the electromagnetic wave transmitted through the wood to be measured at a degree, measuring the attenuation coefficient and the phase coefficient of the wood to be measured from the rotation angle dependency of the received intensity, and a comparison wood of the same type as the wood to be measured in advance And an identification step for identifying the moisture content of the wood to be measured using the obtained correlation coefficient between the moisture content, the attenuation coefficient, and the phase coefficient.

The fifth aspect of the present invention is a wood moisture content identification method for identifying the moisture content of the wood to be measured by irradiating the wood to be measured with electromagnetic waves and receiving the electromagnetic waves transmitted through the wood to be measured, A comparative wood of the same kind as the wood to be measured is completely dried, and the transmitting wood that radiates electromagnetic waves is irradiated with electromagnetic waves to the comparative wood, and the transmitting antenna and a receiving antenna that receives the transmitted electromagnetic waves. The electromagnetic wave transmitted through the comparison wood at each rotation angle is rotated with the propagation direction of the electromagnetic wave as an axis, and the reception antenna receives the electromagnetic wave. The attenuation coefficient and phase coefficient of the comparison wood are determined from the rotation angle dependency of the received intensity. Measuring step, setting the attenuation coefficient and the phase coefficient as an initial attenuation coefficient and an initial phase coefficient, and moistening the comparative wood to a first moisture content, Rotate the transmitting antenna and the receiving antenna around the propagation direction of the electromagnetic wave while irradiating the material with the electromagnetic wave, receive the electromagnetic wave transmitted through the comparative wood at each rotation angle, and depend on the rotation angle of the received intensity the attenuation coefficient and phase coefficient of the comparative timber was measured from gender, a setting step of setting the damping coefficient and said phase coefficient set to attenuation coefficient and phase coefficient of the first moisture content, the comparative timber Moistening so that the second moisture content is different from the first moisture content, and setting the attenuation coefficient and the phase coefficient in the second moisture content are repeated a plurality of times, and the moisture content and the attenuation in the comparative wood are compared. A determination step for determining a correlation coefficient between a coefficient and a phase coefficient; and a direction in which the electromagnetic wave propagates with respect to the transmitting antenna and the receiving antenna in a state where the measured wood is irradiated with the electromagnetic wave. And receiving the electromagnetic wave transmitted through the wood to be measured at each rotation angle, measuring the attenuation coefficient and the phase coefficient of the wood to be measured from the rotation angle dependency of the received intensity, And an identification step of identifying the moisture content of the wood to be measured using an initial attenuation coefficient, the initial phase coefficient, and the correlation coefficient.

The sixth aspect of the present invention is a wood moisture content identification method for identifying the moisture content of the wood to be measured by irradiating the wood to be measured with electromagnetic waves and receiving the electromagnetic waves transmitted through the wood to be measured. A plurality of transmissions arranged at respective rotation angles about the propagation direction of the electromagnetic wave in a state where the comparative wood of the same kind as the wood to be measured is completely dry, and the comparative wood in the dry state is irradiated with electromagnetic waves. The comparison wood is passed between a pair of an antenna and a reception antenna, the electromagnetic wave transmitted through the comparison wood is received, and the attenuation coefficient and the phase coefficient of the comparison wood are determined from the rotation angle dependency of the reception intensity. A setting step for setting the attenuation coefficient and the phase coefficient as an initial attenuation coefficient and an initial phase coefficient, and moistening the wood for comparison in a dry state to a first moisture content, and applying electromagnetic waves to the wood for comparison Propagation of electromagnetic waves in the irradiated state The comparison wood is passed between a pair of the transmission antennas and the reception antennas arranged at a rotation angle with the direction as an axis, the electromagnetic waves transmitted through the comparison wood are received, and the reception intensity depends on the rotation angle. determining an attenuation coefficient and phase coefficient of the comparative timber from sex, a setting step of setting the damping coefficient and said phase coefficient set to attenuation coefficient and phase coefficient of the first moisture content, the comparative timber Moistening so that the second moisture content is different from the first moisture content, and setting the attenuation coefficient and the phase coefficient in the second moisture content are repeated a plurality of times, and the moisture content and the attenuation in the comparative wood are compared. A determination step for determining a correlation coefficient between a coefficient and a phase coefficient; and in a state where the electromagnetic wave is irradiated to the measured wood, the measured wooden material is passed between a plurality of pairs of the transmitting antenna and the receiving antenna, Receiving electromagnetic waves transmitted through the wood to be measured at each rotation angle with the carrying direction as an axis, measuring the attenuation coefficient and phase coefficient of the wood to be measured from the rotation angle dependency of the received intensity, And an identification step for identifying the moisture content of the wood to be measured using the initial attenuation coefficient, the initial phase coefficient, and the correlation coefficient.

  According to the present invention, for the same type of wood as the wood to be measured, the initial attenuation coefficient, the initial phase coefficient, and the correlation coefficient with the moisture content, which are essential electrical characteristics determined for each type of wood, are measured in advance. In addition, since the moisture content of the wood to be measured is identified using electrical characteristics, there is no variation caused by the type of wood, and a moisture content with higher accuracy can be identified.

It is a block diagram of the wood moisture content identification apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows the relationship between the rotation angle in the case of Agatis, and the transmittance | permeability. It is a figure which shows the relationship between the rotation angle in the case of a cypress, and the transmittance | permeability. It is a figure which shows the relationship between the rotation angle in the case of a cedar, and the transmittance | permeability. It is a figure which shows the relationship between the moisture content in the case of a cypress, an attenuation coefficient, and a phase coefficient. It is a flowchart which shows the moisture content identification method of 1st Embodiment. It is a figure which shows the transmitting antenna and receiving antenna in the 2nd Embodiment of this invention. It is a flowchart which shows the moisture content identification method of 2nd Embodiment. It is a conventional wood moisture content identification device.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<First Embodiment>
FIG. 1 shows a wood moisture content identification (measurement) apparatus according to a first embodiment of the present invention. In this embodiment, the moisture content is identified (measured) by rotating the transmitting antenna 3 and the receiving antenna 4.

  The wood moisture content identification apparatus shown in the figure includes a measured wood 1, a signal generator 2 that generates an electromagnetic wave signal, a transmission antenna 3 that radiates electromagnetic waves, and a receiving antenna 4 that receives the electromagnetic waves transmitted through the measured wood 1. A synchronous rotating stage 5 (rotating means) that rotates the transmitting antenna 3 and the receiving antenna 4 in synchronization with the propagation direction of the electromagnetic wave (the main lobe direction of the antenna) as an axis, and the signal output from the receiving antenna 4 is the rotating stage 5 And a measuring instrument 6 for recording each angle. The transmitting antenna 3 and the receiving antenna 4 are arranged to face each other so as to sandwich the measured wood 1.

  Note that when the frequency of the electromagnetic wave is low, it is difficult to increase the directivity of the transmission antenna 3, so that the electromagnetic wave diffuses and is scattered by a part other than wood and detected by the receiving antenna 4, and the measurement accuracy is high. The noise is reduced. In order to suppress the diffusion of electromagnetic waves, the electromagnetic waves are collimated using a lens on the output side of the transmitting antenna 3, and the electromagnetic waves are focused on the input side of the receiving antenna 4 using a similar lens, thereby reducing noise due to scattering. In addition, the detection amount of the receiving antenna 4 can be increased.

  Further, it is difficult to directly measure an electromagnetic wave signal having a very high frequency such as a millimeter wave, and it is also possible to down-convert it to a signal having a frequency that can be detected using homodyne detection or heterodyne detection.

  Next, a method for identifying the moisture content will be described.

  In this embodiment, a 100 GHz Gunn diode is used for the signal generator 2, a horn antenna is used for the transmitting antenna 3 and the receiving antenna 4, a single-convex Teflon lens is used for collimating and focusing electromagnetic waves, and a lock-in amplifier is used for the measuring instrument 6. .

  The signal output from the signal generator 2 was amplitude-modulated with a 100 kHz signal, the signal received by the receiving antenna 4 was detected with a Schottky diode, and then only the 100 kHz component was extracted with a lock-in amplifier. In the present embodiment, as the wood 1 to be measured, Agathis, Japanese cypress, and Japanese cedar were used.

  First, the synchronous rotary stage 5 is rotated in a state where electromagnetic waves are irradiated to the wood to be measured in a completely dry state, and the reception intensity at each rotation angle is recorded by the measuring instrument 6. Similarly, the wood to be measured is wetted to each moisture content (for example, 12.1%, 17.2%, 25.0%, 35.3%, 65.0%, etc. for cypress) The received intensity at the rotation angle was recorded. The value obtained by standardizing each received signal was defined as the transmittance (relative transmittance) when the measured wood was not installed.

  FIG. 2, FIG. 3 and FIG. 4 show the relationship between each rotation angle and transmittance in each wood. FIG. 2 is a diagram showing the relationship between the rotation angle and the transmittance in the case of Agatis. FIG. 3 is a diagram showing the relationship between the rotation angle and transmittance in the case of cypress. FIG. 4 is a diagram showing the relationship between the rotation angle and the transmittance in the case of cedar.

  2, 3, and 4 schematically show the rotation angle of the antenna (the direction of vibration (polarization) of the electromagnetic wave) with respect to the fiber (grain) direction of the wood to be measured. In the illustrated example, the rotation angles are 0 °, 45 °, and 90 °.

As shown in FIG. 2, FIG. 3, and FIG. 4, the transmittance changes with each rotation angle, and the transmittance also changes with the moisture content. The relationship between the transmittance T and the rotation angle θ is given by the following formula 1.

Here, t _AW and t _WA are reflection coefficients on the surface and the opposite surface. d is the thickness of the sample (wood to be measured). αx, βx, αy, and βy are an attenuation coefficient and a phase coefficient in the fiber direction, and an attenuation coefficient and a phase coefficient in a direction perpendicular to the fiber direction, respectively. Using equation 1, αx, βx, αy, and βy at each water content can be calculated.

  FIG. 5 shows the relationship between the moisture content, the attenuation coefficient αx in the fiber direction of the cypress, the phase coefficient βx, the attenuation coefficient αy in the direction perpendicular to the fiber direction of the cypress, and the phase coefficient βy. FIG. 5 shows the attenuation coefficients αx and αy and the phase coefficients βx and βy based on the above equation 1 from the characteristics of the change in transmittance with respect to the angle change between the cypress fiber direction and the electromagnetic wave vibration direction shown in FIG. Is. FIG. 5 shows that αx, βx, αy, and βy monotonically increase with respect to the moisture content, and that the moisture content can be uniquely identified by measuring αx, βx, αy, and βy. In the present embodiment, attenuation coefficients αx and αy and phase coefficients βx and βy with respect to a change in the moisture content of wood as shown in FIG. 5 are acquired.

  Similarly, in Agathis and Basigi, the relationship as shown in FIG. 5 is obtained from the graphs of FIGS. 2 and 4, and the moisture content can be uniquely identified.

  A procedure for specifically using the moisture content identification method of the present embodiment described above will be described.

  FIG. 6 is a flowchart showing an identification method performed by the wood moisture content identification device of the present embodiment. The comparison wood of the same type as the wood to be measured is brought into a completely dry state (S11), and the transmitting antenna and the receiving antenna are rotated with the propagation direction of the electromagnetic wave as an axis in a state where electromagnetic waves are irradiated to the comparative wood in the completely dry state ( S12, S13), receiving electromagnetic waves transmitted through the comparative wood at the respective rotation angles (S14), determining the attenuation coefficient and phase coefficient of the comparative wood from the rotation angle dependence of the received intensity (S15), and the attenuation The coefficient and the phase coefficient are set as the initial attenuation coefficient and the initial phase coefficient (S16).

  Then, the comparative wood is wetted to have different moisture contents (S17), and the same processing as in S12 to S15 is repeated to determine the attenuation coefficient and the phase coefficient of the comparative wood in the wet state (S18). . That is, the transmitting and receiving antennas are rotated around the propagation direction of the electromagnetic wave while the electromagnetic wave is applied to the comparative wood, and the electromagnetic waves transmitted through the comparative wood are received at the respective rotation angles, and the received intensity depends on the rotational angle. The damping coefficient and the phase coefficient of the comparative wood in the wet state are determined from the property, and the damping coefficient and the phase coefficient are set as the damping coefficient and the phase coefficient at the moisture content.

  Further, S17 and S18 are repeated in a plurality of different wet states (S19). That is, the process of setting the attenuation coefficient and the phase coefficient at each moisture content is repeated a plurality of times by moistening the comparative wood to have a plurality of different moisture contents. Then, a correlation coefficient between the moisture content, the attenuation coefficient, and the phase coefficient in the comparative wood is determined (S20).

  Then, using the measured wood instead of the comparative wood, the processing from S12 to S15 is performed, and the attenuation coefficient and the phase coefficient of the measured wood are measured (S21). That is, the transmitting and receiving antennas are rotated around the propagation direction of the electromagnetic wave while the electromagnetic wave is irradiated on the measured wood, and the electromagnetic wave transmitted through the measured wooden at each rotation angle is received, and the received intensity depends on the rotational angle. The attenuation coefficient and phase coefficient of the wood to be measured are measured from the properties.

  Then, the attenuation coefficient and phase coefficient of the wood to be measured measured in S21 are compared with the correlation coefficient between the initial attenuation coefficient and the phase coefficient of the comparative wood acquired in S16 and S20 (refer to), and the wood to be measured Is determined and identified (S22).

<Second Embodiment>
In the second embodiment, instead of the method of identifying the moisture content by rotating the transmitting antenna and the receiving antenna described in the first embodiment, the moisture content is obtained by using a pair of transmitting and receiving antennas having a plurality of different rotation angles. Identify rates.

  From Equation 1 above, the transmittance T depends on the rotation angle θ, and the inconstant is four, αx, βx, αy, and βy. Therefore, the transmittance is measured by measuring the transmittance at four rotation angles. αx, βx, αy, βy can be determined.

  Therefore, as shown in FIG. 7, the moisture content can be identified by arranging transmission / reception antenna pairs having four different rotation angles in the longitudinal direction of the measured wood 1 and moving the measured wood 1 linearly. . In the example shown in FIG. 7, the transmitter 41a and the receiver 42a are a first transmission / reception antenna pair, the transmitter 41b and the receiver 42b are a second transmission / reception antenna pair, and the transmitter 41c and the receiver 42c. Are a third transmitting / receiving antenna pair, and the transmitter 41d and the receiver 42d are a fourth transmitting / receiving antenna pair.

  As can be seen from FIG. 2 to FIG. 4, the change in transmittance with respect to the rotation angle of the antenna is one cycle at 360 °. By setting the angle difference between the transmission / reception antenna pair to 90 °, which is an angle obtained by dividing 360 ° into four, identification time by calculation can be shortened.

  A procedure for specifically using the method of arranging a plurality of transmission / reception antenna pairs and identifying the moisture content of wood will be described.

  FIG. 8 is a flowchart showing the method for identifying the moisture content of the present embodiment. A comparative wood of the same type as the wood to be measured is completely dried (S41), and the electromagnetic waves are irradiated to the comparative wood, and a plurality of transmission / reception antenna pairs arranged at a rotation angle with the propagation direction of the electromagnetic wave as an axis. Is passed through the comparison wood (S42), the electromagnetic wave transmitted through the comparison wood at each rotation angle is received (S43), and the attenuation coefficient and the phase coefficient of the comparison wood are determined from the dependency of the received intensity on the rotation angle. (S44) The attenuation coefficient and phase coefficient in the completely dry state are set as the initial attenuation coefficient and initial phase coefficient (S45).

  The comparative wood is moistened to have different moisture contents (S46), and the same processing as S42 to S44 is repeated to determine the attenuation coefficient and the phase coefficient of the comparative wood in the wet state (S47). That is, in a state in which the comparative wood is irradiated with electromagnetic waves, the comparative wood is passed between a plurality of transmission / reception antenna pairs arranged at a rotation angle about the propagation direction of the electromagnetic waves, and the comparative wood at each rotation angle is passed. The transmitted electromagnetic wave is received, the attenuation coefficient and phase coefficient of the comparative wood are identified from the dependency of the received intensity on the rotation angle, and the attenuation coefficient and phase coefficient are set as the attenuation coefficient and phase coefficient for the moisture content.

  Further, S46 and S47 are repeated in a plurality of different wet states (S48). That is, the process of setting the attenuation coefficient and the phase coefficient at each moisture content is repeated a plurality of times by moistening the comparative wood to have a plurality of different moisture contents. Then, a correlation coefficient between the moisture content, the attenuation coefficient, and the phase coefficient in the comparative wood is determined (S49).

  Then, using the measured wood instead of the comparative wood, the processing from S42 to S44 is performed, and the attenuation coefficient and the phase coefficient of the measured wood are measured (S50). That is, in a state where electromagnetic waves are irradiated to the measured wood, a comparative wood is passed between a plurality of transmission / reception antenna pairs arranged at a rotation angle about the propagation direction of the electromagnetic waves, and the measured wood at each rotation angle is passed The transmitted electromagnetic wave is received, and the attenuation coefficient and the phase coefficient of the wood to be measured are measured from the rotation angle dependence of the received intensity.

  Then, the wood to be measured is compared with the correlation coefficient between the initial attenuation coefficient and the phase coefficient of the comparative wood acquired in S45 and S49 with respect to the attenuation coefficient and the phase coefficient of the wood to be measured measured in S50. Is determined and identified (S51).

  In the first and second embodiments described above, the water content is determined by using the amount of electromagnetic wave transmitted through the wood at only one of the angles formed by the vibration direction of the electromagnetic wave and the traveling direction of the wood fibers (grains). Since the moisture content is identified using the wood permeation amount of electromagnetic waves at a plurality of angles without identifying the rate, variation in the identified moisture content can be reduced.

  That is, in this embodiment, for the comparative wood of the same type as the wood to be measured, the initial attenuation coefficient, the initial phase coefficient, and the correlation coefficient with the moisture content, which are essential electrical characteristics determined for each type of wood, are measured. In addition, since the moisture content of the wood to be measured is identified using this electrical characteristic, there is no variation caused by the type of wood, and a more accurate moisture content can be identified.

  In addition, this invention is not limited to the said embodiment, Many deformation | transformation are possible within the range of the summary.

DESCRIPTION OF SYMBOLS 1 Measured timber 2 Signal generator 3 Receiving antenna 4 Synchronous rotation stage 5 Measuring instrument 41a-41d Transmitter 42a-42d Receiver

Claims (11)

A wood moisture content identification device for identifying the moisture content of the wood to be measured by irradiating the wood to be measured with electromagnetic waves and receiving the electromagnetic waves transmitted through the wood to be measured,
A transmitting antenna that radiates electromagnetic waves;
A receiving antenna for receiving transmitted electromagnetic waves;
Wherein arranged to face and said receiving antenna and said transmitting antenna so as to sandwich the measured wood, in synchronization with the transmitting antenna and the receiving antenna have a rotating means for rotating the direction of propagation of the electromagnetic wave as the axis ,
The transmitting antenna and the receiving antenna are rotated around the propagation direction of the electromagnetic wave while the electromagnetic wave is irradiated to the measured wood, and the electromagnetic wave transmitted through the measured wooden material at each rotation angle is received. Measure the attenuation coefficient and phase coefficient of the measured wood from the rotation angle dependence,
The moisture content of the wood to be measured is identified using a correlation coefficient between the moisture content, the attenuation coefficient, and the phase coefficient obtained in advance for the same type of comparative wood as the measured wood. Identification device. A wood moisture content identification device for identifying the moisture content of the wood to be measured by irradiating the wood to be measured with electromagnetic waves and receiving the electromagnetic waves transmitted through the wood to be measured,
A plurality of pairs of transmitting antennas for radiating electromagnetic waves and receiving antennas for receiving transmitted electromagnetic waves;
Each of the plurality of pairs of transmission antennas and reception antennas is arranged to face each other with the measured wood sandwiched therebetween, and the paired transmission antennas and reception antennas are arranged at the same rotation angle with the propagation direction of the electromagnetic wave as an axis. ,
The plurality of pairs of transmitting antennas and receiving antennas are arranged in a straight line ,
In a state in which the measured wood is irradiated with electromagnetic waves, the measured wood is passed between a plurality of pairs of the transmission antenna and the receiving antenna, and the measured wood at respective rotation angles about the propagation direction of the electromagnetic waves. Receiving the electromagnetic wave that passes through, measuring the attenuation coefficient and phase coefficient of the measured wood from the rotation angle dependence of the received intensity,
The moisture content of the wood to be measured is identified using a correlation coefficient between the moisture content, the attenuation coefficient, and the phase coefficient obtained in advance for the same type of comparative wood as the measured wood. Identification device. The wood moisture content identification device according to claim 2,
The plurality of pairs of transmitting antennas and the receiving antennas are four pairs,
The wood moisture content identification device, wherein the four pairs of transmitting antennas and the receiving antennas are arranged so as to have a difference in rotation angle of 90 ° from each other. The wood moisture content identification device according to any one of claims 1 to 3,
When identifying the moisture content of the measured wood,
Furthermore, the initial attenuation coefficient and the initial phase coefficient, which are attenuation coefficients and phase coefficients in a completely dry state, obtained in advance for the same type of comparative wood as the measured wood are used.
Wood moisture content identification device. The wood moisture content identification device according to claim 1,
The correlation coefficient between the moisture content, the attenuation coefficient, and the phase coefficient obtained in advance for the same type of comparative wood as the measured wood is:
The comparative wood is completely dry, and the electromagnetic wave is applied to the comparative wood by the transmitting antenna that irradiates the electromagnetic wave, and the propagation direction of the electromagnetic wave is changed between the transmitting antenna and the receiving antenna that receives the transmitted electromagnetic wave. The receiving antenna receives the electromagnetic waves transmitted through the comparative wood at each rotation angle, measures the attenuation coefficient and phase coefficient of the comparative wood from the rotation angle dependence of the received intensity, and rotates the attenuation. Set the coefficient and the phase coefficient as the initial attenuation coefficient and the initial phase coefficient,
The comparative wood is moistened to have a first moisture content, and the transmission antenna and the receiving antenna are rotated around the propagation direction of the electromagnetic wave in a state where the comparative wood is irradiated with electromagnetic waves, and the respective rotation angles are rotated. Receiving the electromagnetic wave transmitted through the comparative wood, measuring the attenuation coefficient and phase coefficient of the comparative wood from the rotation angle dependence of the received intensity, and calculating the attenuation coefficient and the phase coefficient at the first moisture content. Set as attenuation coefficient and phase coefficient,
Deciding by repeating a plurality of times that the comparative wood is wetted to have a second moisture content different from the first moisture content, and setting the attenuation coefficient and phase coefficient at the second moisture content.
Wood moisture content identification device. The wood moisture content identification device according to claim 2,
The correlation coefficient between the moisture content, the attenuation coefficient, and the phase coefficient obtained in advance for the same type of comparative wood as the measured wood is:
A pair of a plurality of transmitting antennas and receiving antennas arranged at respective rotation angles with the propagation direction of the electromagnetic wave as an axis in a state where the comparative wood is completely dry and the electromagnetic wave is irradiated to the comparative wood in the completely dry state. The comparison wood is passed through, the electromagnetic wave transmitted through the comparison wood is received, the attenuation coefficient and phase coefficient of the comparison wood are determined from the rotation angle dependence of the received intensity, and the attenuation coefficient and the Set the phase factor as the initial damping factor and initial phase factor,
The plurality of transmitting antennas disposed at a rotation angle about the propagation direction of the electromagnetic wave in a state where the comparative wood in the completely dry state is wetted to have a first moisture content and the electromagnetic wave is irradiated to the comparative wood. And the pair of receiving antennas are passed through the comparative wood, receive electromagnetic waves transmitted through the comparative wood, and determine the attenuation coefficient and phase coefficient of the comparative wood from the rotation angle dependence of the received intensity. , Setting the attenuation coefficient and the phase coefficient as the attenuation coefficient and the phase coefficient at the first moisture content,
Deciding by repeating a plurality of times that the comparative wood is wetted to have a second moisture content different from the first moisture content, and setting the attenuation coefficient and phase coefficient at the second moisture content.
Wood moisture content identification device. A wood moisture content identification method for identifying the moisture content of the wood to be measured by irradiating the wood to be measured with electromagnetic waves and receiving the electromagnetic waves transmitted through the wood to be measured,
A transmitting antenna that radiates electromagnetic waves;
A receiving antenna for receiving transmitted electromagnetic waves;
A wood having rotating means for arranging the transmitting antenna and the receiving antenna so as to sandwich the wood to be measured and rotating the transmitting antenna and the receiving antenna in synchronization with the propagation direction of the electromagnetic wave as an axis Using a moisture content identification device,
The transmitting antenna and the receiving antenna are rotated around the propagation direction of the electromagnetic wave while the electromagnetic wave is irradiated to the measured wood, and the electromagnetic wave transmitted through the measured wooden material at each rotation angle is received. Measuring the attenuation coefficient and phase coefficient of the wood to be measured from the rotation angle dependence;
An identification step for identifying the moisture content of the wood to be measured using a correlation coefficient between the moisture content, the attenuation coefficient, and the phase coefficient, which is obtained in advance for the same type of comparative wood as the wood to be measured.
A method for identifying moisture content of wood. A wood moisture content identification method for identifying the moisture content of the wood to be measured by irradiating the wood to be measured with electromagnetic waves and receiving the electromagnetic waves transmitted through the wood to be measured,
A plurality of pairs of transmitting antennas for radiating electromagnetic waves and receiving antennas for receiving transmitted electromagnetic waves;
Each of the plurality of pairs of transmission antennas and reception antennas is arranged to face each other with the measured wood sandwiched therebetween, and the paired transmission antennas and reception antennas are arranged at the same rotation angle with the propagation direction of the electromagnetic wave as an axis. ,
Using the wood moisture content identification device in which the plurality of pairs of transmitting antennas and receiving antennas are arranged in a straight line,
In a state in which the measured wood is irradiated with electromagnetic waves, the measured wood is passed between a plurality of pairs of the transmission antenna and the receiving antenna, and the measured wood at respective rotation angles about the propagation direction of the electromagnetic waves. Receiving the electromagnetic wave that passes through and measuring the attenuation coefficient and phase coefficient of the wood to be measured from the rotation angle dependence of the received intensity;
An identification step for identifying the moisture content of the wood to be measured using a correlation coefficient between the moisture content, the attenuation coefficient, and the phase coefficient, which is obtained in advance for the same type of comparative wood as the wood to be measured.
A method for identifying moisture content of wood. The wood moisture content identification method according to claim 7 or 8,
In the identification step,
Furthermore, the wood moisture content identification method characterized by using an initial attenuation coefficient and an initial phase coefficient, which are attenuation coefficients and phase coefficients in a completely dry state, obtained in advance for the same type of comparative wood as the measured wood. A wood moisture content identification method for identifying the moisture content of the wood to be measured by irradiating the wood to be measured with electromagnetic waves and receiving the electromagnetic waves transmitted through the wood to be measured,
A comparative wood of the same kind as the wood to be measured is completely dried, and the transmitting wood that radiates electromagnetic waves is irradiated with electromagnetic waves to the comparative wood, and the transmitting antenna and a receiving antenna that receives the transmitted electromagnetic waves. The electromagnetic wave transmitted through the comparison wood at each rotation angle is rotated with the propagation direction of the electromagnetic wave as an axis, and the reception antenna receives the electromagnetic wave. The attenuation coefficient and phase coefficient of the comparison wood are determined from the rotation angle dependency of the received intensity. And setting the attenuation coefficient and the phase coefficient as an initial attenuation coefficient and an initial phase coefficient,
The comparative wood is moistened to have a first moisture content, and the transmission antenna and the receiving antenna are rotated around the propagation direction of the electromagnetic wave in a state where the comparative wood is irradiated with electromagnetic waves, and the respective rotation angles are rotated. Receiving the electromagnetic wave transmitted through the comparative wood, measuring the attenuation coefficient and phase coefficient of the comparative wood from the rotation angle dependence of the received intensity, and calculating the attenuation coefficient and the phase coefficient at the first moisture content. a setting step of setting as an attenuation coefficient and phase coefficient,
The step of moistening the comparative wood to a second moisture content different from the first moisture content, and setting the attenuation coefficient and the phase coefficient at the second moisture content is repeated a plurality of times, and the comparative wood A determination step for determining a correlation coefficient between a moisture content and an attenuation coefficient and a phase coefficient in
The transmitting antenna and the receiving antenna are rotated around the propagation direction of the electromagnetic wave while the electromagnetic wave is irradiated to the measured wood, and the electromagnetic wave transmitted through the measured wooden material at each rotation angle is received. The attenuation coefficient and phase coefficient of the wood to be measured are measured from the rotation angle dependency, and the moisture content of the wood to be measured is determined using the initial attenuation coefficient, the initial phase coefficient, and the correlation coefficient of the comparative wood. An identification step for identifying the wood moisture content identification method. A wood moisture content identification method for identifying the moisture content of the wood to be measured by irradiating the wood to be measured with electromagnetic waves and receiving the electromagnetic waves transmitted through the wood to be measured,
A plurality of transmissions arranged at respective rotation angles about the propagation direction of the electromagnetic wave in a state where the comparative wood of the same kind as the wood to be measured is completely dry, and the comparative wood in the dry state is irradiated with electromagnetic waves. The comparison wood is passed between a pair of an antenna and a reception antenna, the electromagnetic wave transmitted through the comparison wood is received, and the attenuation coefficient and the phase coefficient of the comparison wood are determined from the rotation angle dependency of the reception intensity. A setting step for setting the attenuation coefficient and the phase coefficient as an initial attenuation coefficient and an initial phase coefficient;
The plurality of transmitting antennas disposed at a rotation angle about the propagation direction of the electromagnetic wave in a state where the comparative wood in the completely dry state is wetted to have a first moisture content and the electromagnetic wave is irradiated to the comparative wood. And the pair of receiving antennas are passed through the comparative wood, receive electromagnetic waves transmitted through the comparative wood, and determine the attenuation coefficient and phase coefficient of the comparative wood from the rotation angle dependence of the received intensity. a setting step of setting the damping coefficient and said phase coefficient set to attenuation coefficient and phase coefficient of the first moisture content,
The step of moistening the comparative wood to a second moisture content different from the first moisture content, and setting the attenuation coefficient and the phase coefficient at the second moisture content is repeated a plurality of times, and the comparative wood A determination step for determining a correlation coefficient between a moisture content and an attenuation coefficient and a phase coefficient in
In a state in which the measured wood is irradiated with electromagnetic waves, the measured wood is passed between a plurality of pairs of the transmission antenna and the receiving antenna, and the measured wood at respective rotation angles about the propagation direction of the electromagnetic waves. The attenuation coefficient and phase coefficient of the wood to be measured are measured from the rotation angle dependence of the received intensity, and the initial attenuation coefficient, the initial phase coefficient, and the correlation coefficient of the comparative wood are An identification step of identifying the moisture content of the wood to be measured by using a wood moisture content identification method.