KR20240077445A - Measurement system using terahertz wave - Google Patents

Abstract

A coating film measurement system using terahertz waves, comprising a terahertz module including a terahertz wave emitter and a terahertz wave detection unit, a robot arm on which the terahertz wave module is mounted on a head, and the terahertz wave module is mounted on a measurement object. Terahertz waves are irradiated from the Hertz wave emitter, the terahertz wave detection unit detects the terahertz waves reflected from the measurement object, and the detected terahertz waves are analyzed to measure the thickness of the coating film.

Description

Terahertz wave measurement system {MEASUREMENT SYSTEM USING TERAHERTZ WAVE}

The present invention relates to a terahertz wave measurement system, and more specifically, to a measurement system that measures the thickness of a paint film or coating layer using terahertz waves.

Defects due to vehicle quality problems amount to 4 million vehicles annually in Korea alone, resulting in losses of approximately 1 trillion won, of which corrosion and quality problems in automobile bodies and wheel paint films account for approximately 350,000 cases per year. Accurate paint or coating film thickness management is a very important quality control element in the surface treatment industry, and film thickness management is necessary to maintain quality not only in vehicles but also in ships and steel structures.

The quality of the coating system is governed by the paint manufacturer's product specifications. Each layer, from the primer to the topcoat and the individual intermediate layers, is specified with a precise minimum and maximum coating thickness, and the thickness of the dry film as well as the wet film is controlled. If the coating film thickness is thin, rapid corrosion due to poor corrosion prevention, partial corrosion due to the coating surface opening, etc. may occur, and if the coating film thickness is thick, there are problems with raw material cost, coating bleeding, cracking, dry heat, breakage, and excessive drying time. . If the film thickness is not constant, problems such as technical problems and additional costs arise, so there is a great need for equipment that can non-destructively inspect the film thickness in real time during the film formation process.

Currently, the method of inspecting the quality of a coating film is mainly a destructive inspection technique using an optical microscope that breaks the test specimen and measures the thickness of the coating film.

As a non-destructive test, the film thickness can be measured using various methods such as existing X-ray test, infrared test, and ultrasonic test. However, existing non-destructive methods are difficult to apply to measure the thickness of anti-corrosion coatings in the machinery, automobile, and construction fields because it is difficult to increase the measurement speed and it is difficult to configure an automatic measurement system in industrial sites. In addition, non-destructive testing such as ultrasonic testing requires contact measurement with the object, so it takes a long time and may have problems such as damaging the object.

Registered Patent Publication No. 10-1788450

In order to solve the above problems, the present invention seeks to provide a terahertz wave (Thz) non-destructive measurement system that can measure the thickness of multi-layer paint and can be applied even during the manufacturing process.

The present invention also seeks to provide a terahertz wave automatic film thickness measurement system that automatically measures the shape of the measurement object, designates measurement points, and accurately measures many measurement points in a short time using a robot.

A coating film measurement system using terahertz waves to solve the above problem includes a terahertz module including a terahertz wave emitter and a terahertz wave detection unit, and a robot arm on which the terahertz wave module is mounted on a head. , terahertz waves are irradiated from the terahertz wave emitter to the measuring object, the terahertz wave detection unit detects the terahertz waves reflected from the measuring object, and the detected terahertz waves are analyzed to measure the thickness of the coating film. do.

A terahertz wave measurement system according to another aspect of the present invention includes a base portion where a three-dimensional shape measurement area is located on one side and a terahertz wave measurement area is located on the other side; a 3D shape measuring unit that measures the 3D external shape of a measurement object disposed in the 3D shape measurement area; a terahertz wave measurement unit disposed in the terahertz wave measurement area and automatically measuring the film thickness formed on the surface of the measurement object using terahertz waves according to a measurement recipe generated based on the measured three-dimensional external shape; a transfer unit for transferring the measurement object for which the 3D shape measurement has been completed in the 3D shape measurement area from the 3D shape measurement area to the terahertz wave measurement area; and a control unit that controls the entire terahertz wave measurement system.

The terahertz wave measurement unit includes a robot arm, a terahertz wave module mounted on the head of the robot arm, an optical system for terahertz generation and detection connected to the terahertz module through an optical fiber, and a terahertz wave measurement unit on the surface of the measurement object. Includes a position detection unit to measure the direction and distance of wave irradiation.

According to the system of the present invention, an automatic coating film thickness measurement system is provided that can automatically measure the shape of a measurement object on which a coating film is formed and measure the thickness of the coating film in real time with terahertz waves based on the measurement information.

According to another aspect of the present invention, real-time measurement is possible by implementing fast measurement speed even on the painted surface of a 3D curved object using a terahertz wave module mounted on a 3D articulated robot.

Figure 1 is a plan view showing the layout of a terahertz wave optical system.
Figure 2 is a photograph of the terahertz wave generation and detection optical system.
Figure 3 is a conceptual diagram of a terahertz wave optical system and laser transmission according to an embodiment of the present invention.
Figure 4 is a diagram showing a state in which a terahertz wave module according to an embodiment of the present invention is installed on a robot arm.
Figure 5 is a perspective view and a top view of a terahertz wave measurement system according to an embodiment of the present invention.
Figure 6 is a diagram showing the process of acquiring a 3D shape and creating a measurement point of a terahertz wave measurement system according to an embodiment of the present invention.
Figure 7 is a measurement point editing screen of Figure 6, and Figure 8 is an automatic measurement screen in which the recipe is reflected.
Figure 9 is a diagram illustrating the concept of controlling the posture of a measurement head using a laser spot of a terahertz wave system according to an embodiment of the present invention.
Figure 10 is a diagram schematically showing the arrangement of the laser of the position detection unit installed on the robot arm head and the vision camera and the relationship between the surface of the measurement object and the laser spot image captured by the vision camera, respectively, according to an embodiment of the present invention. .
Figure 11 is a picture showing the change in the shape of the laser spot image when the distance from the surface of the measurement object in the z-axis (surface normal direction) of the position detection unit according to an embodiment of the present invention is changed.
Figure 12 exemplarily shows a laser spot imaging image according to an embodiment of the present invention.
Figure 13 is a graph showing the relationship between the sum of distances between the centers of spots in an image by a position detection unit according to an embodiment of the present invention and the z-axis position.
Figure 14 is a formula for calculating the signal and thickness measured by the measurement head of Figure 9.
Figure 15 shows the results of the measurement speed test.

With reference to the attached drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. In order to clearly explain the present invention in the drawings, parts unrelated to the description are omitted, and similar parts are given similar reference numerals throughout the specification. In this process, the thickness of lines or sizes of components shown in the drawings may be exaggerated for clarity and convenience of explanation.

Throughout the specification, when a part is said to be “connected” or “coupled” with another part, this means not only when it is “directly connected” or “directly coupled”, but also when it has other components in between. Also includes cases where it is “connected” or “combined.” Additionally, when a part "includes" a certain component, this means that it may further include other components rather than excluding other components, unless specifically stated to the contrary.

Terahertz waves are electromagnetic waves with a tera-level frequency of 10 ¹² to 10 ¹⁴ Hz, between infrared and microwaves, and have characteristics that vary in transmission and reflection depending on the electrical characteristics of the object. Terahertz waves have the advantage of being able to penetrate opaque samples through which visible light does not pass and have a shorter wavelength than microwaves, resulting in higher resolution, so they can be used in various fields such as measuring semiconductor properties and multilayer films, measuring film thickness, detecting defects, and biomedical care. The trend is expanding.

A terahertz wave measuring device generally includes a terahertz wave generator, a first optical system that radiates terahertz waves generated from the terahertz wave generator to a sample, and a terahertz wave that is irradiated and reflected by the sample and guides to a detector. It includes a second optical system, a detector for detecting the reflected terahertz wave, and an arithmetic unit for processing the detector signal.

Terahertz waves are generated by optical rectification in a photoconductor that responds to a femtosecond pulse laser. That is, a femtosecond pulse laser is irradiated to a terahertz emitter (THz emitter) including a photoconductive antenna (PCA), thereby generating a terahertz wave pulse.

Figure 1 is a plan view showing the layout of a terahertz wave optical system. According to Figure 1, the femtosecond pulse laser emitted from the femtosecond pulse light source passes through a wavelength converter and filter and is branched by a beam splitter, and part of it (Beam 1) passes through a delay stage (scan delay) to a terahertz emitter (THz). It is irradiated to the emitter and functions as a pump light for generating terahertz wave pulses, and the other part (Beam 2) is guided to the detector and functions as a probe beam. Terahertz waves (THz) generated from the terahertz emitter by the femtosecond pulse are focused by the first optical system (PM1, PM2), irradiated to a specific location on the sample, reflected from the sample, and then transmitted to the second optical system (PM3, PM4). It is focused on the detector antenna and the intensity of the reflected light is detected. The probe beam reaches the detector before the terahertz wave reflected by the sample and serves to set the reference point for terahertz wave detection.

The coating film measurement system using terahertz waves according to an embodiment of the present invention has the following configuration.

1. Optical system for generating and detecting terahertz waves

2. Algorithm to measure thickness by analyzing terahertz waves

3. 3D shape measuring unit that measures the 3D shape of an object and automatically creates the measurement area.

4. Terrafa measurement unit that uses an articulated robot to measure the coating film of an object with an arbitrary three-dimensional shape.

5. Control program that controls the entire system

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

Figure 5 is a perspective view (left) and a top view (right) of a terahertz wave measurement system according to an embodiment of the present invention. According to FIG. 5, the terahertz wave measurement system according to an embodiment of the present invention includes a three-dimensional shape measurement unit that measures the three-dimensional shape of an object to be measured (hereinafter referred to as 'measurement object'), and a terahertz wave A terahertz wave measurement unit that measures the film thickness formed on the surface of the measurement object using a transfer unit to transfer the measurement object from the three-dimensional shape measurement area to the terahertz wave measurement area, and the signal measured by the terahertz wave measurement unit. It includes an information processing device that processes information and a control unit (information processing device) that controls the entire terahertz wave measurement system. For example, the measurement object may be the entire car or a portion of the painted surface with a paint film formed on the surface, but is not limited to this and may be various objects with a paint film or coating layer formed on the surface, and the film may be one in which one or more layers are formed.

As shown in Figure 5, the 3D shape measurement unit and the terahertz wave measurement unit are installed on a base such as a stone granite, and a 3D shape measurement zone is on one side of the base and a 3D shape measurement zone is on the other side. The terahertz wave measurement area (thickness measurement zone) is located.

A 3D shape measuring unit that measures the 3D shape of the measurement object is disposed in the 3D shape measurement zone to measure the 3D external shape of the measurement object. The measurement object is automatically transferred from the 3D shape measurement area to the terahertz wave measurement area by the transfer unit. Once the 3D shape of the object to be measured is completed in the 3D shape measurement area, the transfer unit transfers the measurement object to the terahertz wave measurement area. The transfer unit also sequentially transports the measured object a predetermined fine distance (transfer-stop/measurement-transfer-stop/measure) within the 3D shape measurement area so that the 3D shape measuring unit can scan the 3D shape of the measured object. do.

The transfer unit may include a linear moving means installed on the base unit, for example, a transfer rail, a guide block moving along the transfer rail, and a motor. The measurement object is positioned and transported on the guide block.

The three-dimensional shape measuring unit will be described with reference to FIGS. 5 to 8. As shown in the top view of the measurement system shown on the right side of Figure 5, the measurement object (measurement object) obtains the shape of the curved surface through 3D scan using a line laser and camera in the 3D shape measurement zone. It becomes mine. After the curved surface shape is acquired and processed by the information processing device, the coordinates of the measurement target area are transmitted to the robot arm.

Figures 6 to 8 show the 3D scan using a line laser and a camera in the 3D shape measurement area, the acquisition of the 3D shape of the curved surface, and the process of editing the measurement points accordingly.

As shown in Figures 5 and 6, it is installed in the three-dimensional shape measurement area, and a line laser light source and a camera are installed on the upper part of this support part to measure the measurement object transported by the lower transport part. The line laser light source shines a green line laser onto the measurement object and captures images of the measurement object with a camera installed at an angle above the line laser. When a camera obtains an image of an object to which a line laser image has been irradiated, the image has a step in the laser line depending on the height, and by measuring this step, a height profile of one line of the measured object is obtained. By repeating this process (imaging, obtaining a height profile from the image) while moving the measuring object horizontally by a predetermined distance in the direction perpendicular to the laser line by the moving unit, a three-dimensional shape map of the entire object is obtained.

A method of generating 3D shape map data of a measured object through image data processing is performed by an information processing device such as a computer, and the data created in this way is 3D rendered. In addition, a measurement recipe can be created to automatically specify by an algorithm which point to measure in the rendered 3D model, and in some cases, an interface can be provided so that system users can specify and edit the desired measurement point. Figure 7 is an interface screen for editing measurement points. Editing operations such as adding, modifying, and deleting measurement points are performed using the height data map and rendering screen on the left, and the results are saved as a measurement recipe. . The measurement recipe edited in this way is reflected during automatic measurement, as shown in FIG. 8.

The measurement object for which the 3D shape measurement has been completed in the 3D shape measurement area is transferred to the terahertz wave measurement area (thickness measurement zone) by the transfer unit at the bottom. In the terahertz wave measurement area, the coating film of the measurement object is measured based on the measurement recipe generated by the terahertz wave module installed on the robot arm.

Referring to FIGS. 2 to 4, a terahertz wave measurement unit that measures the coating film thickness of a measurement object will be described in detail. The terahertz wave measurement unit includes a multi-joint robot arm, a terahertz wave module mounted on the head of the robot arm, an optical system for terahertz generation and detection connected to the terahertz module through an optical fiber, and a surface of the measurement object. It includes a position detection unit to detect and adjust the irradiation direction and distance of terahertz waves.

The articulated robot arm is placed on one side of the terahertz wave measurement area, and the terahertz wave emitted from the emitter of the terahertz wave module mounted on the head is irradiated in the normal direction to the curved surface of the measurement object by the first optical system. 3D position control is possible. The first optical system that irradiates the emitter and terahertz waves to the measurement object, the second optical system that guides the terahertz waves irradiated and reflected by the measurement object to the detection unit, and the detection unit that detects the reflected terahertz waves are modularized into a single block. is formed and included in the terahertz wave module. At this time, the terahertz wave module may have the same configuration as the terahertz wave module shown in Korean Patent Publication No. 10-2023-0057528, but is not limited to this.

Meanwhile, Figure 2 is a photograph of an optical system for generating and detecting terahertz waves according to an embodiment of the present invention. Referring to FIG. 2, the optical system for terahertz generation and detection is designed to branch the femtosecond laser and transmit it to the antenna for terahertz generation and detection, through an optical element that generates and branches the femtosecond laser in the infrared band. Half goes directly into the emitter connector, and the rest goes through a fast scanner and enters the detector connector with a certain time delay. At this time, a stage is installed to adjust the range for obtaining the signal. The femtosecond laser delivered here is transmitted to the emitter (THz emitter) and detector mounted on the robot arm through optical fiber, as shown in FIG. 3.

The optical system is located at the bottom of the measurement system as shown in Figure 5, and transmits laser to the emitter and detector of the terahertz wave module (THz head) mounted on the robot at the top through optical fiber. The terahertz generation and detection optical system, which has a large volume, is placed at the bottom and transmits the laser via optical fiber to the terahertz wave module mounted on the head of the robot arm. Therefore, the robot arm equipped with the terahertz wave module on the head can move to various positions and postures, so it can freely move the curved surface and freely measure multiple measurement points with the terahertz wave module according to the measurement recipe.

The position detection unit detects the irradiation direction and distance of the terahertz wave on the surface of the measurement object, and based on the detected direction and distance, the control unit detects the position and direction of the terahertz wave module and the robot arm head on which the terahertz wave module is mounted. control.

In order for the terahertz wave irradiated from the emitter of the terahertz wave module to be reflected from the surface of the measurement object and detected by the detection unit, the terahertz wave module must be placed in the normal direction of the surface of the measurement object. In Figure 9, the dotted line is the normal direction of the surface of the measurement object, and the solid arrow indicates that the irradiated terahertz wave is reflected from the surface of the measurement object. In other words, for accurate measurement, the terahertz wave module must be placed facing the normal direction of the surface of the measurement object, and the measurement distance to the surface must be maintained at an appropriate distance.

The position detection unit is placed on the robot arm head adjacent to the terahertz wave module. The position sensing unit includes three laser pointers arranged in an equilateral triangle to form three laser spots on the irradiated surface, and a vision camera positioned at the center of the triangle formed by the three laser pointers. When three laser pointers are irradiated to a surface located in front, the vision camera is positioned on the normal line of the surface and is positioned to capture an equilateral triangle formed by the three points.

Figure 9 is to explain the concept of finding and aligning three laser points to control the terahertz wave module (THz head) in the normal direction so that it is incident perpendicularly on the surface of the object. As shown in Figure 9, three lasers are illuminated near the measurement area, the center of the spot is obtained using a vision camera, and then the difference from when it is aligned in the normal direction is calculated to determine the terahertz wave module (THz head). ) allows the robot to be controlled to be positioned accurately in terms of distance and angle.

Figure 10 shows the arrangement of the laser and vision camera of the position detection unit installed on the head of the robot arm, the relationship with the surface of the measurement object, and the laser spot captured by the vision camera. The three lasers are placed at the vertices of an equilateral triangle with the camera as the center, and the camera optical axis is arranged to be approximately opposite to the center of the laser spot triangle created by the three lasers. Each laser pointer is placed at an angle so that it faces the optical axis in front of the central camera. In Figure 10, only two lasers are visible, but the other laser is placed on the back of the camera. Therefore, when the camera is located on the normal line of the surface of the measurement object, it is preferable that the image captured by the three lasers forms an equilateral triangle, but is not limited to this and can also form a triangle of another defined shape. In this way, using the difference between the triangles of the reference triangle image and the actual measurement image, it is possible to check whether the normal direction of the surface of the measurement object is aligned. That is, the centers of the three laser spots in the image are obtained and aligned in the normal direction using the difference from when the centers were aligned in the normal direction with respect to the surface. After first aligning the normal direction, the distance to the surface can be adjusted. However, this is not limited to this, and the normal direction alignment can also be adjusted after adjusting the distance.

On the other hand, in Figure 10(a), when the measurement distance is close, the distance between the laser spots becomes distant, and (b) is judged to be an appropriate distance. (c) is a case where the measurement distance is long. In this case, the distance between the spots is close. Lose.

Figure 11 shows a change in the shape of a laser spot when the distance from the surface of the measurement object in the z-axis (surface normal direction) changes. By moving the position detection unit installed on the head of the robot arm in the Z-axis direction at regular intervals, the relationship between the distance between the laser spots of imaging and the reference position Z-axis distance is obtained. The closer it is to the reference position, the larger the triangle formed by the 3 spots becomes, and the farther it is from the reference position, the smaller this triangle becomes.

Using this, the distance between the spots at the actual measurement position is obtained and the difference between the Z-axis reference position and the current position is obtained.

FIG. 12 exemplarily shows a laser spot imaging image, where a, b, and c represent the distance between spot centers, respectively. In other words, the current position in the z-axis direction can be known by comparing the sum of the distances between the centers of each laser spot in the image (S=a+b+c) with the sum of the distances between the centers of the spots at the reference position.

Figure 13 is a graph showing the relationship between the sum of distances between spot centers and the z-axis position. Specifically, the horizontal axis (x) of the graph represents the difference from the sum of the distances between the image spot centers at the reference position, and the vertical axis (y) represents the difference with respect to the reference position in the z-axis direction (surface normal direction) of the position detection unit. . Therefore, the origin represents the distance between the spot centers at the reference position as 0 and the reference position as 0. That is, the horizontal axis is SA-SB, the sum of the distance between the centers of the spots at a specific position A in the z-axis direction is SA, the sum of the distances between the centers of the spots of the captured image at the reference position (B) is SB, and the vertical axis is Az. -Bz is the normal distance from the surface at position A, and Bz is the normal distance from the surface at the reference position. The graph in Figure 13 shows that this forms a linear relationship.

Therefore, if the sum of the distances between the centers of the image spots at the current position minus the sum of the distances between the centers of the image spots at the reference position is greater than 0, it is far from the surface and moves to the reference position, and if the value is less than 0, it is too close. Therefore, the reference position moves away from the surface.

Figure 14 shows the process of obtaining a signal from an aligned measurement head to obtain the thickness of the painted surface. By finding the peak of the wave reflected from the surface of the painted surface and the internal metal layer, the difference is calculated as the time difference, and from this, the thickness of the film can be calculated using the refractive index of the material and the flux of light.

The control unit of the terahertz wave measurement system automates the above-described processes by controlling the line laser, camera, transfer unit, information processing device, robot arm, and terahertz wave measurement module.

When measuring multiple points on the sample using this system as shown in Figure 15, the measurement was completed within 1 sec/point, enabling fast measurement speed.

Although the present invention is intended to measure the thickness of a coating film on a curved surface, it can be used to measure the thickness of any coating film through which terahertz waves, including general planes, pass and are reflected.

According to the present invention, basic components and a system for measurement using the spectral characteristics of terahertz waves were developed in a non-destructive and non-contact manner, and a robot was used to automatically measure the shape of the curvature and designate measurement points. , It enables accurate measurement of many measurement points in a short period of time, allowing it to be used in actual industrial sites.

By developing a terahertz wave spectroscopic system and mounting it on a robot-based measurement system that can be used in factories or similar sites to automatically measure film thickness, we will not only enter the existing domestic and overseas non-destructive measurement market, but also use it in automobiles, aircraft, Economic ripple effects can be created by developing various application technologies in fields such as shipping and military logistics.

Claims (7)

A terahertz wave measurement system that measures the thickness of a coating film formed on the surface of a measurement object using terahertz waves,
A terahertz module including a terahertz wave emitter and a terahertz wave detection unit,
A robot arm on which the terahertz wave module is mounted on the head,
It includes a transfer unit that transfers the measurement object,
A terahertz wave is irradiated from the terahertz wave emitter to a measuring object, and the terahertz wave detection unit detects the terahertz wave reflected from the measuring object,
A plurality of laser pointers and vision cameras are disposed on the head of the robot arm for the terahertz module to measure the position of the terahertz wave module with respect to the measurement target surface of the measurement object,
A terahertz wave measurement system in which the plurality of laser pointers each irradiate laser light to the surface of the measurement object, and the vision camera captures an image including a spot of the laser irradiated to the surface of the measurement object.
According to paragraph 1,
Three laser spots are irradiated to the surface by the plurality of laser pointers,
By processing the images of the three laser spots captured by the vision camera, the difference in shape or size from when the three laser spots are aligned at the reference position in the normal direction to the surface of the measurement object is obtained, and the difference in shape or size for the surface is obtained. A terahertz wave measurement system characterized by adjusting the distance and angle of the terahertz wave module.
According to paragraph 1,
A three-dimensional shape measurement unit is disposed on the upstream side of the transfer unit to measure the three-dimensional shape of the measurement object and automatically generate measurement target area information of the measurement object,
A robot unit including the robot arm is disposed on the downstream side of the transfer unit,
A terahertz wave measurement system, wherein the 3D shape measurement unit performs 3D scanning using a line laser and a camera to obtain a 3D map of the measured object.
According to clause 3,
The 3D shape measuring unit shines the line laser on the measurement object and obtains an image with the camera installed at an angle with respect to the line laser,
In the captured image, the laser line has a step depending on the height of the measurement object. This step is measured to obtain a height profile of one line, and by repeating this process while moving the measurement object, a three-dimensional map of the surface of the measurement object is created. A terahertz wave measurement system characterized by obtaining.
As a terahertz wave measurement system,
A base portion in which a three-dimensional shape measurement area is located on one side and a terahertz wave measurement area is located on the other side;
a 3D shape measuring unit that measures the 3D external shape of a measurement object disposed in the 3D shape measurement area;
a terahertz wave measurement unit disposed in the terahertz wave measurement area and automatically measuring the film thickness formed on the surface of the measurement object using terahertz waves according to a measurement recipe generated based on the measured three-dimensional external shape;
a transfer unit for transferring the measurement object for which the 3D shape measurement has been completed in the 3D shape measurement area from the 3D shape measurement area to the terahertz wave measurement area; and
It includes a control unit that controls the entire terahertz wave measurement system,
The terahertz wave measurement unit includes a robot arm, a terahertz wave module mounted on the head of the robot arm, an optical system for terahertz generation and detection connected to the terahertz module through an optical fiber, and a terahertz wave measurement unit on the surface of the measurement object. A terahertz wave measurement system comprising a position detection unit for measuring the irradiation direction and distance of the wave.
According to clause 5,
The three-dimensional shape measuring unit includes a line laser and the camera installed at an angle with respect to the line laser,
The line laser is irradiated to the measurement object, and the camera captures an image of the measurement object with the laser line projected onto the surface,
By processing the captured image, the height profile of one line is obtained by measuring the difference in the laser line according to the height of the measurement object, and by repeating the measurement for each position while moving the measurement object, a three-dimensional map of the surface of the measurement object is obtained. A terahertz wave measurement system characterized by:
According to clause 5,
The position detection unit is placed on the robot arm head adjacent to the terahertz wave module, has three laser pointers arranged in an equilateral triangle to form three laser spots on the surface of the measurement object, and is located at the center of the triangle formed by the three laser pointers. Including a deployed vision camera,
The vision camera acquires an image including a laser spot irradiated by the three laser pointers on the surface of the measurement object,
The position of the terahertz wave module in the z-axis direction is determined by comparing the sum of the distances between the centers of each laser spot in the image (S=a+b+c) with the sum of the distances between the centers of the laser spots in the image acquired at the reference position. A terahertz wave measurement system characterized by confirmation.