KR20150091792A - Methods and apparatuses for calibrating microwave imaging apparatus using variation due to temperature - Google Patents

Abstract

The present invention relates to a method and an apparatus for calibrating a microwave image apparatus using a variation depending on temperature. The apparatus create a database with an amplitude and a phase of an electromagnetic wave according to the temperature of a matching medium inside an accommodating portion without inserting an object to be measured and perform calibration according to the temperature of the matching medium inside the accommodating portion when measuring the object to be measured to increase the accuracy of a value of the calibration, thereby increasing the accuracy of an image restoration result.

Description

TECHNICAL FIELD [0001] The present invention relates to a method and an apparatus for calibrating a radio wave imaging apparatus using temperature-

The present invention relates to a radio wave imaging apparatus, and more particularly, to a method of calibrating a radio wave imaging apparatus.

A technique has been proposed in which the internal dielectric constant and the conductivity distribution of an object to be imaged are imaged by using a propagation characteristic of an electromagnetic wave signal with a technique of acquiring an internal image of the object nondestructively. More specifically, the conventional radio wave imaging apparatus includes a receiving unit filled with a matching solution with a transmitting and receiving antenna, a transmitting and receiving unit transmitting and receiving radio waves to the inside of the water tank to detect an amplitude and a phase value, Restoration section. The difference between the propagation amplitude phase value when the object to be measured is placed inside the receiving portion and the propagation amplitude phase value when the object to be measured is not placed inside the receiving portion is called a calibration value, The image reconstruction unit calculates the permittivity and conductivity distribution in the object to be measured.

At this time, there is a characteristic that the amplitude and phase value of the radio wave vary according to the temperature of the matching medium in the receiver, and accordingly, the calibration value may vary with temperature, which may lower the accuracy of the image restoration result.

FIG. 1 is a graph showing the relationship between the temperature of the matching medium and the temperature of the matching medium from 13 ° C to 30 ° C when the measuring object is absent, the frequency of the used radio wave is 6 GHz, the distance between the transmitting and receiving antennas is 10.6 cm, It is the data which measured the propagation amplitude value. As shown in FIG. 1, as the temperature changes from 13 degrees to 30 degrees, it can be seen that the measured value also changes by 20 dB or more. This is because the permittivity of the matching medium changes as the temperature changes.

If the amplitude and the phase value of the radio wave change according to the temperature as described above, an accurate calibration value can not be obtained and the accuracy of the image restoration result may be degraded.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the problems described above and to provide a method and apparatus for a radio wave imaging apparatus that copes with a change in propagation characteristics of a microwave according to a temperature of a matching medium of the wave apparatus.

According to another aspect of the present invention, there is provided a method of calibrating a radio wave imaging apparatus, the method comprising: positioning a measured object in a receiver; Measuring a temperature of the matching medium in the receiving portion to generate a first temperature value, measuring intensity values and phase values of the radio waves transmitted and received in the receiving portion, Value and a first phase value, and an intensity value and a phase value of a radio wave transmitted and received in the accommodation section at a temperature corresponding to the first temperature value when there is no measured object, Value to generate a calibration value.

According to another aspect of the present invention, there is provided a radio wave imaging apparatus including a receiving unit configured with transmitting / receiving antennas and a matching medium, a radiating unit radiating a radio wave to the receiving unit through the transmitting / A temperature sensor for measuring a temperature of the matching medium in the receiving section, a temperature sensor for measuring a temperature of the matching medium in the receiving section, a temperature measured by the temperature sensor, and an amplitude and a phase value detected by temperature in the transmitting and receiving section, And an image restoration unit for restoring the propagation image using the calibration value.

According to another aspect of the present invention, there is provided a method for calibrating a radio wave imaging apparatus, the method comprising the steps of: receiving a radio wave with respect to each temperature value of a matching medium without inserting a measured object into a receiving unit, Inserting an object to be measured into a receiving unit and measuring a temperature of the matching medium; inserting a measured object into the receiving unit and transmitting and receiving a radio wave to measure an amplitude and a phase value; Extracting an amplitude and a phase value of a radio wave corresponding to the measured temperature value from the database; comparing the amplitude and phase values extracted from the database with the measured temperature and the amplitude and phase values measured by inserting the measured object; Calculating a difference, and transmitting the difference value and difference values of the calculated amplitudes to an external device The.

The method and apparatus for calibrating a radio wave imaging apparatus according to one embodiment of the present invention include a method of preliminarily databaseing the amplitudes and phase values of radio waves according to the temperature of a matching medium inside a receiving portion, The calibration is performed according to the temperature of the matching medium in the receiving part during the measurement of the object to be measured, thereby increasing the accuracy of the calibration value and thereby improving the accuracy of the image restoration result.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a diagram showing a difference in attenuation amount between transmitting and receiving antennas according to a temperature change of a matching medium (13-butylene glycol). FIG.
2 is a conceptual diagram of a calibration apparatus for a radio wave imaging apparatus according to an embodiment of the present invention.
3 is a flowchart illustrating a method of generating amplitude and phase data according to temperature of a radio wave performed in a calibration apparatus of a radio wave imaging apparatus according to an embodiment of the present invention.
4 is a flowchart illustrating a method of performing calibration of a radio wave imaging apparatus performed in a calibration apparatus of a radio wave imaging apparatus according to an embodiment of the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail.

It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component. And / or < / RTI > includes any combination of a plurality of related listed items or any of a plurality of related listed items.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the relevant art and are to be interpreted in an ideal or overly formal sense unless explicitly defined in the present application Do not.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In order to facilitate the understanding of the present invention, the same reference numerals are used for the same constituent elements in the drawings and redundant explanations for the same constituent elements are omitted.

A method of calibrating a radio wave imaging apparatus according to an exemplary embodiment of the present invention enables a non-destructive observation of an internal image of a measured object using radio waves.

2 is a conceptual diagram of a calibration apparatus for a radio wave imaging apparatus according to an embodiment of the present invention. The radio wave imaging apparatus according to an embodiment of the present invention includes a radio wave transmitting and receiving unit 10, a radio wave exposure accommodating unit 20 and an image restoring unit 60 for obtaining a radio wave image, A temperature sensor 80 and a calibration unit 100.

The radio wave exposure accommodating section 20 includes radio wave coupling lines 50a and 50h and antennas 30a and 30h and is provided with a matching medium 90 for impedance matching between the object to be measured 40 and the antennas 30a and 30h ). A matching solution or matching gas may be used as the matching medium 90. The temperature sensor 80 measures the temperature of the receiving portion. The temperature sensor 80 can measure the temperature in the receiving portion, which can be performed by measuring the temperature of the matching medium in the receiving portion. The temperature sensor 80 transfers the measured temperature to the calibration unit 100. The radio wave connection lines 50a and 50h and the antennas 30a and 30h may be included in the radio wave transmission and reception unit 10 and not included in the radio wave reception unit 20 depending on the use.

The radio wave transmitting and receiving section 10 generates radio waves in the radio wave exposure accommodating section 20 using the antennas 30a and 30h of the radio wave exposure accommodating section 20 and receives radio waves transmitted through the matching medium 90. [ For example, the radio wave signal generated from the radio wave transmitting / receiving unit 10 is exposed to the measured object 40 through the antenna 30a located inside the radio wave exposure accommodating portion 20 through the path of the radio wave connection line 50a. The radio wave signal having passed through the object to be measured 40 is inputted to the radio wave transmitting and receiving unit 10 through the antenna 30h through the radio wave connecting line 50h. The radio wave transmitting and receiving unit 10 can receive the radio wave signal passing through the measured object 40 and measure the attenuated radio wave intensity and the changed phase value while passing through the inside of the measured object 40. The radio wave connection lines 50a and 50h and the antennas 30a and 30h may be the radio wave transmission and reception unit 10 and not the radio wave reception unit 20.

The radio wave transmitting / receiving unit 10 transmits information of the received radio waves to the calibration unit 100. For example, the information of the received radio wave may be reception state information of the radio wave, or may be the attenuated radio wave intensity or the changed phase value from the received radio wave data.

The calibration unit 100 measures the intensity (A_h) and the phase value (P_h) of the radio wave measured in the radio wave exposure accommodating portion in the absence of the measured object 40 in the radio wave exposure accommodating portion, (A_c, P_c) by calculating the difference between the intensity (A_d) and the phase (P_d) of the radio wave intensity measured in the radio wave exposure accepting unit when the radio wave 40 exists. The calibration unit 100 transmits the generated calibration values A_c and P_c to the image reconstruction unit 60. For example, the calibration unit 100 may generate the calibration values A_c, P_c using the following equations.

The propagation intensity A_h and the phase value P_h in the absence of the measured object 40 may vary according to the temperature of the matching medium 90 and thus the calibration values A_c and P_c also vary with temperature can do. In consideration of this, the calibration unit 100 may perform a calculation for generating a calibration value according to the temperature of the matching medium 90 in the radio wave exposure accommodating portion.

For example, the calibration unit 100 may store a database (A_h, t) and a phase value (P_h, t) measured in accordance with each temperature in a database when the measured object 40 is absent . The temperature t of the matching medium 90 is measured through the temperature sensor 80 during the measurement of the radio wave intensity A_d and the phase value P_d when the measured object 40 is present, , The calibration value A_c, t, P_c, t can be calculated using the propagation intensity A_h, t and the phase value P_h, t according to the temperature t. The calibration unit 100 may calculate the calibration values A_c, t, P_c, t using the following equations.

The image restoring unit 60 images the permittivity and the conductivity distribution in the object 40 using a normal imaging method using the calibration values A_c and P_c as input values

3 is a flowchart of a method of generating amplitude phase data for each temperature of a radio wave performed in a calibration apparatus of a radio wave imaging apparatus according to an embodiment of the present invention. The calibration apparatus measures the radio wave intensity A_h, t and the phase value P_h, t in the receiving portion according to each temperature when the measured object 40 is not in the receiving portion 20 (homogeneous state) And a database is created.

Referring to FIG. 3, the calibration apparatus first measures the temperature of the matching medium 90 in the absence of a measured object in the receiving unit 20 (S310). Then, the calibration apparatus generates a radio wave inside the receiving portion 20, receives the generated radio wave, and measures the amplitude and phase of the received radio wave (S320). Finally, the calibration device stores the amplitude and phase value data of the received radio wave in the database according to the temperature.

4 is a flowchart illustrating a method of performing calibration of a radio wave imaging apparatus performed in a calibration apparatus of a radio wave imaging apparatus according to an embodiment of the present invention. The calibration apparatus first measures the temperature of the accommodating portion 20 in which the measured object is accommodated (S410). The calibrating device can radiate radio waves into the receiving portion by positioning the measured object 40 inside the receiving portion 20 and measuring the temperature before measuring the temperature using the radio wave transmitting and receiving portion 10. [ Thus, the calibration apparatus can radiate radio waves in the receiving portion, and can measure the temperature in the receiving portion through the temperature sensor 80 when receiving and detecting the radio wave in the receiving portion. For example, the calibration device can measure the temperature of the receiving portion 20 by measuring the temperature of the matching medium 90 in the receiving portion 20. [

Next, the calibration apparatus measures the amplitude and the phase of the radio wave while the measured object is accommodated (S420). The calibration apparatus receives the radio wave that has passed through the measured object in the receiving portion, and measures the amplitude and phase of the received radio wave to generate the amplitude and phase data of the radio wave. The radio wave intensity A_d and the phase value P_d can be measured by the radio wave transmitting and receiving section 10 by the amplitude and phase data of the radio wave.

Next, the calibration apparatus calculates a calibration value (S430). The calibrating device calculates the calibration value using the full width and phase value data of the temperature-dependent radio wave stored in the database, the measured amplitude and phase value data of the radio wave, and the measured temperature. (A_h, t) and phase value (P_h, t) corresponding to the measured temperature (t) are extracted from the database and the extracted propagation intensity and phase value and the propagation intensity (A_c, t, P_c, t) is calculated by calculating the difference value of the value (P_d).

Finally, the calibration device can use the calculated calibration values (A_c, t, P_c, t) to image the permittivity and conductivity distribution within the workpiece. Alternatively, the calibration device may transmit the calibration value calculated by the radio wave imaging device to an external device. For example, the calibration device may transmit the calculated calibration values to a wave imaging device so that the wave imaging device uses the calibration values to image the dielectric constant and conductivity distribution within the workpiece.

While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. It will be apparent to those skilled in the art that the present invention can be carried out without departing from the spirit and scope of the invention.

The combination of the above-described embodiments is not limited to the above-described embodiment, and various combinations of types as well as the above-described embodiments may be provided according to implementation and / or necessity.

In the above-described embodiments, the methods are described on the basis of a flowchart as a series of steps or blocks, but the present invention is not limited to the order of steps, and some steps may occur in different orders or in a different order than the steps described above have. It will also be understood by those skilled in the art that the steps depicted in the flowchart illustrations are not exclusive and that other steps may be included or that one or more steps in the flowchart may be deleted without affecting the scope of the invention You will understand.

The foregoing embodiments include examples of various aspects. While it is not possible to describe every possible combination for expressing various aspects, one of ordinary skill in the art will recognize that other combinations are possible. Accordingly, it is intended that the invention include all alternatives, modifications and variations that fall within the scope of the following claims.

Claims (1)

A method for calibrating a radio wave imaging apparatus, which is performed by a radio wave imaging apparatus calibration apparatus,
Positioning the object to be measured in the receptacle;
Transmitting and receiving radio waves in the receiving portion;
Measuring a temperature of the matching medium in the receiving portion to generate a first temperature value;
Generating a first intensity value and a first phase value by measuring an intensity value and a phase value of a radio wave transmitted and received in the accommodation portion;
Generating a calibration value by using the intensity value and the phase value of the radio wave transmitted and received in the reception unit at a temperature corresponding to the first temperature value when there is no measured object and the first intensity value and the first phase value, Wherein the radio wave imaging device calibration method comprises the steps of:

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