KR101884183B1 - Milimeter wave radiometer system and method thereof - Google Patents

Abstract

The present invention relates to a millimeter-wave radiometer system and method thereof, and a method of calibrating and applying the millimeter-wave radiometer system according to the present invention includes a lens for condensing a millimeter-wave signal radiated from an object, A quasi-optical unit formed by a reflector for bending a direction of 90 degrees, a single channel receiver for converting the condensed millimeter wave signal into a DC signal after amplification and band pass, A three-axis scanner for linearly scanning a single-channel receiver and outputting two-dimensional image data; A system calibration unit for calculating calibration parameters necessary for the single-channel receiver to uniformly calibrate gain characteristics of different single-channel receivers for different positions on the focal plane of the quasi-optical unit using the 3-axis scanner; And an image calibration unit that applies calibration parameters calculated by the system calibration unit to the two-dimensional image acquired through all of the components except for the system calibration unit. In the security search unit of the airport and the public agency, Detection of weapons and information leaking out of the shelter, monitoring of movement of persons and trams remotely in an unchecked environment due to bad weather and visibility in the fence line.

Description

MILIMETER WAVE RADIOMETER SYSTEM AND METHOD THEREOF FIELD OF THE INVENTION [0001]

FIELD OF THE INVENTION The present invention relates to a millimeter wave radiometer system and method, and more particularly, to a system and method for detecting a weapon and information leakage storage device hidden in human clothes at airports and public institutions security checkpoints, The present invention relates to a system calibration and a correction image acquisition method of a millimeter image radiometer using a single channel receiving unit which can be used for monitoring the movement of people and trams remotely.

Generally, a millimeter wave radiometer is a sensor system that expresses an image by using a broadband, low noise, and a customized receiver of electromagnetic wave energy emitted from an object.

These millimeter waves have the advantages of significantly less attenuation due to clouds, fog, rain, dust, and flames compared to visible and infrared regions, and have higher resolution than microwaves. In visible light, images of objects can not be obtained through obstacles such as clouds or fog, but images of objects can be obtained in the millimeter wave band. For this reason, video radiometers have the advantage of obtaining images through obstacles.

However, the conventional millimeter-wave radiometer has a structure in which an expensive receiver must be arranged in both directions of the x-axis and the y-axis in order to acquire an image, especially a two-dimensional image, A method for efficiently calibrating a device for obtaining the same is not disclosed.

It is an object of the present invention to provide a millimeter wave radiometer system and a method thereof, and more particularly, to a millimeter wave radiometer system and method thereof, Detecting weapons and information leakage storage devices, and ensuring bad weather and visibility at the wire rope. System calibration and correction of millimeter image radiometer using a single channel receiver that can be used for monitoring human and tram movement remotely in unconfined environment .

According to an aspect of the present invention, there is provided an illumination optical system comprising: a quasi-optical unit for condensing a millimeter wave beam radiated from an object and changing a traveling direction of the beam; A single channel receiver for converting the condensed millimeter wave beam signal into a DC signal after amplification and band pass; A three-axis scanner for adjusting focus of the quasi-optical unit and the single-channel receiving unit and linearly scanning the single-channel receiving unit to output two-dimensional image data; Wherein the single channel receiver calculates the calibration parameters necessary for equally correcting the gain characteristics of the combinations of the sub-optical unit and the single channel receiver for different positions on the focal plane of the quasi-optical unit using the 3-axis scanner, ; And a video calibration unit for applying calibration parameters calculated by the system calibration unit to the two-dimensional image acquired through all the components except for the system calibration unit, wherein the millimeter including the quasi-optical unit, the single channel receiver, Wave radio meter system.

Preferably, the quasi-optical unit includes an aspheric surface dielectric lens for condensing the millimeter wave beam into a beam having small aberration characteristics, and a metal circular reflector for bending the beam by 90 degrees to reduce the size of the quasi-optical part.

Preferably, the single-channel receiver further comprises: a waveguide-type tapered dielectric rod antenna for receiving the condensed millimeter-wave beam through the suboptical portion in a limited size to a high gain characteristic; A transmission line converter connected to the dielectric rod antenna and converting the ground rod into a grounded coplanar waveguide transmission line; An amplifying unit for amplifying a signal transmitted through the transmission line converting unit and attenuating an unwanted frequency band gain; A detector for converting the amplified signal millimeter wave signal into an LF signal; And an LF unit for amplifying the LF signal and controlling the noise to convert the signal into a DC signal.

Preferably, the three-axis scanner includes a single Z-axis scanner unit for fine-tuning the focus of the sub-optical unit depending on a distance between the object and the sub-optical unit; And an X-Y 2-axis scanner unit for acquiring a two-dimensional image through the linear scanning of the single-channel receiving unit.

Preferably, the system calibrating unit includes liquid quenching and radio wave absorbers used as reference objects when calibrating the quasi-optical unit and the single-channel receiving unit, and includes a quasi-optical unit and a single-channel receiving unit In order to calibrate the gain characteristic, the two-dimensional DC value is acquired through the two-dimensional linear scan of the single channel receiver with the three-axis scanner while observing the liquid nitrogen at once, and the two-dimensional DC value for the radio wave absorber is obtained once, To 5 < th > steps.

In the first step, the reference temperatures (T ^H and T ^C ) of the radio wave absorber and liquid nitrogen and the voltages (V ^H and V ^C ) corresponding thereto are input.

)을 획득한다.In the second process, a DC value (i.e.,

).

)을 획득한다.In the third step, the DC value for the two-dimensional image acquisition area for liquid nitrogen (

).

,

을 아래의 식 1에 대입하여 교정 파라미터들을 산출한다.In the fourth step,

,

Is substituted into Equation 1 below to calculate calibration parameters.

(Equation 1)

는 단일 채널 수신부의 이득 특성 파라미터이고, B_i,j는 단일 채널 수신부의 오프셋 특성 파라미터를 뜻한다.here,

Is the gain characteristic parameter of the single channel receiver, and B _{i, j} is the offset characteristic parameter of the single channel receiver.

,

을 아래의 식 2에 대입하여 교정 파라미터들을 산출한다.In the fifth step,

,

Is substituted into Equation 2 below to calculate calibration parameters.

(Equation 2)

, α_i,j는 이득 교정 파라미터이고, β_i,j는 오프셋 교정 파라미터를 뜻한다.here,

,? _{i, j} is the gain calibration parameter, and? _{i, j} is the offset calibration parameter.

Preferably, the image correcting unit obtains the two-dimensional calibration image data through the first and second processes described below on the two-dimensional quasi-image obtained through the image radiometer system by the two-dimensional calibration parameters calculated by the system calibration unit can do.

)을 획득한다.Here, in the first step, a two-dimensional DC value (

).

In the second step, the corrected calibration parameters calculated by the system calibration unit are calibrated using Equation 3 below.

(Equation 3)

According to the millimeter wave radiometer system and method of the present invention as described above, it is possible to detect weapons and information leakage storage devices hidden in human clothes at airport and public institutions security checkpoints, There is an advantage that it can be used for monitoring the movement of persons and trams remotely in a non-environment.

FIG. 1 is a block diagram of an entire system for explaining a millimeter wave radiometer system according to an embodiment of the present invention. Referring to FIG.
2 is a schematic diagram for explaining a quasi-optical part applied to an embodiment of the present invention.
FIG. 3 is a block diagram illustrating a single-channel receiving unit according to an embodiment of the present invention. Referring to FIG.
4 is a conceptual diagram for schematically explaining a 3-axis scanner applied to an embodiment of the present invention.
5 is a flowchart illustrating a process of calculating two-dimensional calibration parameters through a system calibration unit applied to an embodiment of the present invention.
6 is a flowchart illustrating a process of acquiring 2D calibration image data through a video calibration unit applied to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the following embodiments of the present invention may be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below. The embodiments of the present invention are provided to enable those skilled in the art to more fully understand the present invention.

First, a method of calibrating and applying an image to a millimeter wave radiometer system according to the present invention includes a lens that condenses a millimeter wave signal radiated from an object, a quasi-optical A single channel receiver for converting the condensed millimeter wave signal into a DC signal after amplification and band pass; a controller for adjusting the focus of the quasi optical unit and the single channel receiver, linearly scanning the single channel receiver, A three-axis scanner for outputting; A system calibration unit for calculating calibration parameters necessary for the single-channel receiver to uniformly calibrate gain characteristics of different single-channel receivers for different positions on the focal plane of the quasi-optical unit using the 3-axis scanner; And an image calibration unit that applies calibration parameters calculated by the system calibration unit to the two-dimensional image acquired through all of the components except for the system calibration unit. In the security search unit of the airport and the public agency, Detecting weapons and information leaks hidden within the network, ensuring adverse weather and visibility on the fence line. It can be used to remotely monitor the movement of people and tanks in an uncontrolled environment.

FIG. 1 is a block diagram of an entire system for explaining a millimeter wave radiometer system according to an embodiment of the present invention. FIG. 2 is a schematic diagram for explaining a quasi-optical unit applied to an embodiment of the present invention, FIG. 3 is a block diagram illustrating a single-channel receiving unit according to an embodiment of the present invention. FIG. 4 is a conceptual diagram for schematically explaining a 3-axis scanner applied to an embodiment of the present invention. FIG. 6 is a flowchart for explaining a process of calculating two-dimensional calibration parameters through a system calibration unit applied to an embodiment of the present invention. FIG. 6 is a flowchart illustrating a process of obtaining 2-dimensional calibration image data through a video calibration unit applied to an embodiment of the present invention FIG.

1 to 6, a millimeter wave radiometer system according to an embodiment of the present invention includes a quasi-optical unit 110 for condensing a millimeter wave beam radiated from an object and changing a traveling direction of the beam, A single channel receiving unit 120 for converting the condensed millimeter wave beam signal into a DC signal through amplification and band pass, and a single channel receiving unit 120 for adjusting the focus of the quasi optical unit 110 and the single channel receiving unit 120, A three-axis scanner 130 that linearly scans the receiving unit 120 and outputs two-dimensional image data; and a three-axis scanner 130 that uses the three-axis scanner 130 to detect the focal point of the quasi-optical unit 110 A system calibration unit 140 for calculating calibration parameters required to uniformly calibrate the gain characteristics of different combinations of quasi-optic and single-channel receiver units at different positions on the plane, A two-dimensional image obtained through the all configuration comprising one such image calibration unit 150 for applying a calibration parameter calculated by the system calibration unit 140.

As shown in FIG. 2, the quasi-optical unit 110 includes an aspherical dielectric lens 210 and a quasi-optical unit 110 for condensing the millimeter wave beam into a beam having a small aberration characteristic, And includes a metal circular reflector 220 for bending the beam by 90 degrees.

As shown in FIG. 3, the single-channel receiving unit 120 may include a waveguide-type tapered dielectric rod antenna for receiving a millimeter-wave beam condensed through the sub-optical unit 110 in a limited size, A transmission line conversion unit 320 connected to the dielectric rod antenna 310 and converting the ground line signal into a grounded coplanar waveguide transmission line; a transmission line conversion unit 320 amplifying a signal transmitted through the transmission line conversion unit 320, An amplification unit 330 for attenuating the band gain, a detection unit 340 for converting the amplified signal millimeter wave signal into an LF signal, an LF unit 340 for amplifying the LF signal, 350).

As shown in FIG. 4, the three-axis scanner 130 includes a single Z-axis scanner unit 410 for finely adjusting the focus of the sub-optical unit 110 depending on the distance between the object and the sub-optical unit 110 And an XY 2-axis scanner unit 420 for acquiring a two-dimensional image through the linear scanning of the single-channel receiving unit 120.

The system calibration unit 140 includes liquid nitrogen and radio wave absorber used as a reference object when calibrating the quasi-optical unit 110 and the single-channel receiving unit 120, In order to calibrate the gain characteristics of the quasi optical unit 110 and the single channel receiving unit 120 according to the position, the single channel receiving unit 120 is scanned by the three-axis scanner 130 through the two- Dimensional DC value of the radio wave absorber is acquired, and the two-dimensional DC value for the radio wave absorber is obtained once and the two-dimensional calibration parameters are calculated through the following first through fifth processes as shown in FIG.

In the first step, the reference temperatures (T ^H and T ^C ) of the radio wave absorber and liquid nitrogen and the voltages (V ^H and V ^C ) corresponding thereto are input.

)을 획득한다.In the second process, a DC value (i.e.,

).

)을 획득한다.In the third step, the DC value for the two-dimensional image acquisition area for liquid nitrogen (

).

,

을 아래의 식 1에 대입하여 교정 파라미터들을 산출한다.In the fourth step,

,

Is substituted into Equation 1 below to calculate calibration parameters.

(Equation 1)

는 단일 채널 수신부의 이득 특성 파라미터이고, B_i,j는 단일 채널 수신부의 오프셋 특성 파라미터를 뜻한다.here,

Is the gain characteristic parameter of the single channel receiver, and B _{i, j} is the offset characteristic parameter of the single channel receiver.

,

을 아래의 식 2에 대입하여 교정 파라미터들을 산출한다.In the fifth step,

,

Is substituted into Equation 2 below to calculate calibration parameters.

(Equation 2)

, α_i,j는 이득 교정 파라미터이고, β_i,j는 오프셋 교정 파라미터를 뜻한다.here,

,? _{i, j} is the gain calibration parameter, and? _{i, j} is the offset calibration parameter.

The image calibration unit 150 receives the two-dimensional calibration parameters calculated by the system calibration unit 140, as shown in FIG. 6, on a two-dimensional quasi-image acquired through the image radiometer system, And acquires the two-dimensional corrected image data through the second process.

)을 획득한다.Here, in the first step, a two-dimensional DC value (

).

In the second process, the calibration parameters calculated by the system calibration unit 140 are calibrated using Equation 3 below.

(Equation 3)

Although the preferred embodiments of the millimeter wave radiometer system and method according to the present invention have been described above, the present invention is not limited thereto, but may be variously embodied in the claims, the detailed description of the invention, And this also belongs to the present invention.

110: quasi-optical part,
120: single channel receiver,
130: Three-axis scanner,
140: System Correction,
150:

Claims (6)

A quasi-optical unit for condensing the millimeter wave beam radiated from the object and changing the traveling direction of the beam;
A single channel receiver for converting the condensed millimeter wave beam signal into a DC signal after amplification and band pass;
A three-axis scanner for adjusting focus of the quasi-optical unit and the single-channel receiving unit and linearly scanning the single-channel receiving unit to output two-dimensional image data;
Wherein the single channel receiver calculates the calibration parameters necessary for equally correcting the gain characteristics of the combinations of the sub-optical unit and the single channel receiver for different positions on the focal plane of the quasi-optical unit using the 3-axis scanner, ; And
And an image calibration unit for applying calibration parameters calculated by the system calibration unit to the two-dimensional image acquired through all the components other than the system calibration unit,
A quasi-optical unit, a single-channel receiving unit, and a three-axis scanner,
The system calibration unit includes liquid nitrogen and a radio wave absorber used as a reference object when calibrating the quasi-optical unit and the single-channel receiver, and the gain characteristic of the quasi-optical unit and the single-channel receiver according to the focal plane position of the quasi- In order to calibrate, the liquid crystal display device obtains a two-dimensional DC value through a two-dimensional linear scan of the single-channel receiver with the three-axis scanner while observing liquid nitrogen, acquires a two-dimensional DC value for the radio wave absorber once and calculates two- Wherein the millimeter wave radiometer system comprises:
The image display apparatus according to claim 1,
An aspherical dielectric lens for condensing the millimeter wave beam into a beam having a small aberration characteristic, and a metal circular reflector for bending the beam by 90 degrees to reduce the size of the sub optical part.
2. The apparatus of claim 1, wherein the single-
An end tapered dielectric rod antenna in the form of a waveguide that receives a millimeter wave beam condensed through the quasi-optical portion in a limited size and in a high gain characteristic;
A transmission line converter connected to the dielectric rod antenna and converting the ground rod into a grounded coplanar waveguide transmission line;
An amplifying unit for amplifying a signal transmitted through the transmission line converting unit and attenuating an unwanted frequency band gain;
A detector for converting the amplified signal millimeter wave signal into an LF signal; And
And an LF unit for amplifying the LF signal and controlling noise to convert the signal into a DC signal.
The apparatus of claim 1, wherein the three-
A single Z-axis scanner unit for finely adjusting a focus of a sub-optical unit depending on a distance between an object and the sub-optical unit; And
And an XY two-axis scanner unit for acquiring a two-dimensional image through the linear scanning of the single-channel receiving unit.
The system according to claim 1,
The reference temperatures (T ^H , T ^C ) of the radio wave absorber and liquid nitrogen and the voltages (V ^H , V ^C )
The DC value for the two-dimensional image acquisition area for the radio wave absorber (

),
The DC value for the two-dimensional image acquisition area for the liquid nitrogen (

),
remind

,

Is substituted into Equation 1 below to calculate calibration parameters,
remind

,

Is substituted into the following equation (2) to calculate calibration parameters.
(Equation 1)

here,

Is the gain characteristic parameter of the single channel receiver, and B _{i, j} is the offset characteristic parameter of the single channel receiver.
(Equation 2)

here,

,? _{i, j} is the gain calibration parameter, and? _{i, j} is the offset calibration parameter.
The image processing apparatus according to claim 1,
Dimensional calibration image data obtained through the first and second processes on a two-dimensional quasi-image acquired through an image radiometer system, the two-dimensional calibration parameters calculated by the system calibration unit, Radio meter system.
Here, in the first step, a two-dimensional DC value (

).
In the second step, the corrected calibration parameters calculated by the system calibration unit are calibrated using Equation 3 below.
(Equation 3)

Here,? _{I, j} is a gain calibration parameter, and? _{I, j} means an offset calibration parameter.

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