JP2019086523A - Terahertz wave imaging device and terahertz wave imaging method - Google Patents

Abstract

To provide a terahertz wave imaging device and a terahertz wave imaging method which suitably synthesize a terahertz wave image.SOLUTION: A terahertz wave imaging device includes: irradiation means (110) for irradiating an object (500) with terahertz waves; first image acquisition means (150) for acquiring first images by detecting the terahertz waves which have been reflected or transmitted by the object; second image acquisition means (170) for acquiring second images by detecting light different from the terahertz waves which have been reflected or transmitted by the object; and synthesis means (240) for synthesizing the plurality of first images corresponding to the second images on the basis of the second images.SELECTED DRAWING: Figure 1

Description

  The present invention relates to the technical fields of, for example, a terahertz wave imaging apparatus and a terahertz wave imaging method which perform imaging by detecting a terahertz wave reflected or transmitted by an object.

  In recent years, research and development of terahertz wave imaging has been activated, and for example, applications to nondestructive inspection and the like have been expected. In these applications, imaging that visualizes an object to be inspected that can not be visually confirmed is used as an effective information presentation method.

  When performing imaging, it is required to scan the inspection target or a head that transmits and receives terahertz waves, but in many cases it is not possible to scan the inspection target itself, and a head scanning type device is considered . For example, Patent Document 1 proposes a technique in which a movable carriage mounted with a small head is driven by a motor to perform automatic scanning. Further, Patent Document 2 proposes a technique for realizing high-speed scanning with a small head by using a mirror or lens that rotates or swings.

JP, 2011-508226, A JP, 2009-8658, A

  However, when trying to realize automatic scanning using a drive device as in Patent Document 1, downsizing of the entire device is difficult, and as a result, the installation location is limited, and imaging when brought into various sites is It will be difficult.

  Further, in the apparatus as in Patent Document 2, the scanning range and the size of the optical system are a trade-off. For this reason, for example, when trying to operate a wide range, the head becomes larger due to the enlargement of the lens diameter etc. Conversely, when trying to miniaturize the head, the scanning range becomes narrow, and only a limited area is inspected The situation that it can not do will occur.

  As a method of solving the above-mentioned problems, it is conceivable to manually scan a small head. However, in the manual scanning, it is not possible to specify the head position by the drive mechanism or the like. For this reason, even if a compact head can scan a wide area, the correspondence between the detected terahertz wave and the scanning position can not be identified, and a technical problem arises that an appropriate image can not be obtained.

  The problems to be solved by the present invention are as mentioned above. An object of the present invention is to provide a terahertz wave imaging apparatus and a terahertz wave imaging method capable of realizing suitable imaging even when it is difficult to mechanically specify a head position as in manual scanning. .

  A terahertz wave imaging device that solves the above problems includes: an irradiation unit that irradiates a terahertz wave to an object; and detecting the terahertz wave reflected or transmitted by the object to obtain a first image that acquires a first image Means, second image acquisition means for detecting light different from the terahertz wave reflected or transmitted by the object, and acquiring a second image, and the second image based on the second image And combining means for combining the plurality of first images corresponding to the images.

  A terahertz wave imaging method for solving the above problems includes an irradiation step of irradiating a terahertz wave to an object, and detecting the terahertz wave reflected or transmitted by the object to obtain a first image. A second image acquisition step of detecting a light different from the terahertz wave reflected or transmitted by the object and acquiring a second image; and the second image based on the second image. Combining the plurality of first images corresponding to the images.

FIG. 1 is a schematic view showing an entire configuration of a terahertz wave imaging apparatus according to a first embodiment. It is a side view which shows the usage example of the terahertz wave imaging device concerning 1st Example. It is a perspective view which shows the imaging method in the terahertz wave imaging device concerning 1st Example. It is a conceptual diagram which shows the synthetic | combination method of a terahertz wave image and a visible light image. It is a side view which shows the usage example of the terahertz wave imaging device concerning 2nd Example. It is a top view which shows the structure of an index part. It is a conceptual diagram which shows the synthetic | combination method of the image using an index part.

<1>
The terahertz wave imaging apparatus according to the present embodiment includes an irradiation unit that irradiates a target with a terahertz wave, and a first image acquisition that detects the terahertz wave reflected or transmitted by the target and acquires a first image. Means, second image acquisition means for detecting light different from the terahertz wave reflected or transmitted by the object, and acquiring a second image, and the second image based on the second image And combining means for combining the plurality of first images corresponding to the images.

According to the terahertz wave imaging device of the present embodiment, at the time of the operation, the terahertz wave is emitted from the irradiation unit toward the target (that is, the imaging target). The terahertz wave is an electromagnetic wave that belongs to a frequency region (that is, a terahertz region) around 1 terahertz (1 THz = 10 ¹² Hz). The irradiation unit includes, for example, a generating element configured as a photoconductive antenna (PCA), a resonant tunneling diode (RTD), or the like.

  The irradiated terahertz wave is reflected or transmitted by the object and detected by the first image acquisition unit. The first image acquisition means include a detection element configured as, for example, a photoconductive antenna or a resonant tunneling diode. Furthermore, the first image acquisition unit performs various processes on the signal corresponding to the detected terahertz wave to acquire a first image. That is, the “first image” is an image captured using a terahertz wave. Note that a plurality of first images are acquired by changing the scanning position (that is, the imaging position) with respect to the object.

  On the other hand, in the second image acquisition means, light different from the terahertz wave reflected or transmitted by the object is detected, and a second image is acquired. Here, “light different from terahertz wave” is light that can be used for imaging an object, and a characteristic different from terahertz wave in imaging (specifically, a characteristic that can realize synthesis described later) It is the light which it has. The “second image” is an image captured using light different from that of the terahertz wave, and is acquired as an image corresponding to the first image. In addition, as an example of a 2nd image acquisition means, a CCD (Charge Coupled Device) camera, a CMOS (Complementary Metal Oxide Semiconductor) sensor, a laser scanner etc. are mention | raise | lifted.

  The plurality of first images acquired using the terahertz wave are combined by the combining means to be an image showing a wide range of the object. However, due to the characteristics of a captured image using terahertz waves, it is difficult to determine which part of the object is captured from the image itself in the first image. Therefore, when the scanning position can not be specified mechanically, for example, as in the case of acquiring the first image by manual scanning, the positional relationship between the plurality of first images can not be specified, and as a result, a plurality of first images are obtained. It will be difficult to properly combine the images.

  However, in the present embodiment, the composition of the plurality of first images is performed based on the second image. Here, in particular, since the second image is an image acquired by light (for example, visible light) different from the terahertz wave, the positional relationship of the images is easy, unlike the first image using the teralahertz wave. Can be identified. Therefore, by using the positional relationship derived from the second image, the positional relationship of the corresponding first image can be specified, and the composition can be appropriately performed. Here, “corresponding” refers to the relationship between the first image and the second image acquired at the same time or very close timing, and typically, the first image and the second image The images of are each obtained as the corresponding pair of images. However, the corresponding first and second images do not necessarily have to be images of the same position of the object, and the relative positional relationship between the first and second images becomes clear. There is no need to Since the positional relationship of the respective second images in the entire synthesized second image is applied to the positional relationship of the corresponding (paired) respective first images, the composition of the first image can be achieved. is there.

  As described above, according to the terahertz wave imaging device according to the present embodiment, the terahertz wave is acquired using the second image acquired using light different from the terahertz wave. Can be properly synthesized. Therefore, imaging using terahertz waves can be performed extremely suitably.

<2>
In one aspect of the terahertz wave imaging device according to the present embodiment, the second image acquisition unit detects visible light reflected by the object and acquires the second image.

  According to this aspect, since the second image is acquired as a visible light image, it is possible to preferably specify the positional relationship of the images by using, for example, the shape or the pattern of the surface of the object. Therefore, by using such a second image, it is possible to appropriately combine the first image acquired using the terahertz wave.

<3>
In another aspect of the terahertz wave imaging device according to the present embodiment, the second image acquisition unit acquires the second image as one including a pattern of an index unit covering the object, and the combining unit is configured to A plurality of the first images are synthesized based on the pattern of the index portion included in the second image.

  According to this aspect, imaging is performed in a state in which the index unit is disposed so as to cover the object. The index part is configured, for example, as a sheet-like or plate-like member, and has on its surface a predetermined pattern that can be imaged using light different from terahertz waves. Thus, the second image includes the pattern of the index part.

  The second image is, for example, a visible light image as described above, so that the positional relationship of the images can be suitably identified using the shape, pattern, etc. of the surface of the object. However, when there is no feature on the surface of the object (for example, a white wall or the like), it is difficult to specify the positional relationship.

  However, in the present aspect, since the second image includes the pattern of the index part, the positional relationship can be suitably identified using the pattern. Therefore, even if the second image is used, the disadvantage that the positional relationship of the first image can not be identified can be reliably avoided.

<4>
In the aspect using the pattern of the index part as described above, the index part may include a material whose transmittance of the terahertz wave is higher than a predetermined threshold value.

  In this case, it is possible to prevent the reflection or transmission of the terahertz wave in the object from being blocked due to the arrangement of the index part. The “predetermined threshold value” may be determined by simulation or the like in advance as a value capable of acquiring the first image with sufficient quality. Examples of the material having high transmittance of terahertz wave include fluorine resin and ultrahigh molecular weight polyethylene.

<5>
In another aspect of the terahertz wave imaging device according to the present embodiment, a display in which the first image and the second image combined by the combining unit are displayed separately or in accordance with a correspondence relationship with each other. Means are provided.

  According to this aspect, the first image, which is an image using terahertz waves, and the second image, which is an image (for example, a visible light image) using light different from the terahertz waves, using the display means And can be displayed separately. That is, only the first image can be displayed, or only the second image can be displayed.

  Further, in the present embodiment, in particular, the first image and the second image can be superimposed and displayed according to the correspondence. Specifically, the first image indicating the internal structure of the object and the second image indicating the surface shape of the object can be superimposed and displayed in a state in which the positional relationship between the first image and the second image is matched. According to such a display method, for example, the internal structure of the object can be intuitively understood, which is extremely useful in practice.

<6>
The terahertz wave imaging method according to the present embodiment includes an irradiation step of irradiating a terahertz wave to an object, and detecting the terahertz wave reflected or transmitted by the object to obtain a first image. A second image acquisition step of detecting a light different from the terahertz wave reflected or transmitted by the object and acquiring a second image; and the second image based on the second image. Combining the plurality of first images corresponding to the images.

  According to the terahertz wave imaging method according to the present embodiment, similarly to the terahertz wave imaging device described above, the terahertz wave is used by using the second image acquired using light different from the terahertz wave. The first image acquired can be appropriately synthesized. Therefore, imaging using terahertz waves can be performed extremely suitably.

  Also in the terahertz wave imaging method according to the present embodiment, it is possible to adopt various aspects similar to the various aspects in the terahertz wave imaging device according to the above-described present embodiment.

  The operation and other gains of the terahertz wave imaging apparatus and the terahertz wave imaging method according to the present embodiment will be described in more detail in the following examples.

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

First Embodiment
First, the configuration and basic operation of the terahertz wave imaging device according to the first embodiment will be described with reference to FIG. FIG. 1 is a schematic view showing the overall configuration of the terahertz wave imaging apparatus according to the first embodiment.

  In FIG. 1, the terahertz wave imaging apparatus according to the first embodiment is configured to irradiate the terahertz wave to the inspection object 500 which is the measurement object and to detect the terahertz wave reflected from the inspection object 500. . That is, the terahertz wave imaging device according to the first embodiment is configured as a so-called reflection type device. The terahertz wave imaging device may be configured as a transmission type device that detects the terahertz wave transmitted in the inspection target.

  The terahertz wave imaging apparatus according to the first embodiment includes a terahertz wave imaging head unit 100 and a control / signal processing unit 200. During operation of the terahertz wave imaging apparatus according to the first embodiment, the terahertz wave imaging head unit 100 performs irradiation and detection of the terahertz wave. The detection result of the terahertz wave is processed by the control / signal processing unit 200, and is output as an image showing the internal structure of the inspection object 500.

  More specifically, the terahertz wave is generated by the terahertz wave transmission unit 110 of the terahertz wave imaging head unit 100. The terahertz wave transmission unit 110 is configured to include, for example, a terahertz wave generation element 111 configured as a resonant tunneling diode or a photoconductive antenna, a hemispherical silicon lens 112, and a collimator lens 113. The terahertz wave generated by the terahertz wave generation element 111 is efficiently extracted by the silicon lens 112, and is transmitted as a terahertz wave beam by the collimator lens.

  The transmitted terahertz wave beam is guided to the beam scanner 130 through the beam splitter 120 configured as, for example, a prism. The beam scanner 130 scans the terahertz wave beam by driving a mechanism that swings or rotates a movable mirror such as, for example, a galvano scanner or a polygon mirror. The beam can be scanned linearly using these mechanisms. In addition, combining two similar mechanisms enables two-dimensional beam scanning.

  The terahertz wave beam scanned by the beam scanner 130 is focused by the objective lens 140 and irradiated toward the inspection object 500. The irradiated terahertz wave beam is reflected by the inspection object 500, and the reflected terahertz wave beam is guided to the beam splitter 120 through the objective lens 140 and the beam scanner 130 again. The terahertz wave beam reflected and returned by the inspection object 500 is reflected by the beam splitter 120 and guided to the terahertz wave receiving unit 150.

  The terahertz wave reception unit 150 is configured to include a condenser lens 151, a hemispherical silicon lens 152, and a terahertz wave detection element 153 configured as a resonant tunnel diode or a photoconductive antenna. In the terahertz wave reception unit 150, the terahertz wave beam narrowed by the condenser lens 151 is efficiently collected by the hemispherical silicon lens 152 in the terahertz wave detection element 153, and a current corresponding to the intensity of the terahertz wave is detected. The detected current is converted into a voltage by the IV converter 160, and is output to the control / signal processing unit 200 as a detection signal.

  The terahertz wave generation element 111 and the terahertz wave detection element 153 are biased by the bias voltage generated by the bias generation unit 210, and the terahertz wave to be transmitted or received changes according to the bias voltage. When the terahertz wave generation element 111 and the terahertz wave detection element 153 are photoconductive antennas, it is necessary to further cause light to act, and transmission and reception of terahertz waves in a very wide band are performed by irradiating ultrashort pulse laser light. be able to.

  Since terahertz waves transmitted and received by the terahertz wave generation element 111 and the terahertz wave detection element 153 are generally weak, lock-in detection is used for the detection. At the time of lock-in detection, the terahertz wave transmission unit 110 uses a reference signal modulated as a bias voltage of the terahertz wave generation element 111. The lock-in detection unit 220 performs synchronous detection using the detection signal of the terahertz wave modulated by the bias generation unit 210 and the reference signal output from the bias generation unit 210. Then, noise components having frequencies different from those of the terahertz wave detection signal reference signal are removed. On the other hand, as the bias voltage of the terahertz wave detection element 153, a direct current voltage is applied such that the detection sensitivity becomes high in the characteristics of the terahertz wave generation element 111.

  The beam scanner 130 is drive-controlled based on a drive signal from the scanner drive unit 230, and scans the terahertz wave beam irradiated to the inspection object 500. The image processing unit 240 acquires a terahertz wave image unit including a scanning position controlled by the scanner drive unit 230 and a detection signal to be received in the terahertz wave irradiation area determined by the scanning range. In addition, when not scanning, the beam scanner 130 acts as a mere mirror which determines an irradiation position. In this case, the irradiation area corresponds to a beam spot, and the terahertz wave image unit is the detection signal itself.

  On the other hand, the visible light imaging device 170 is configured as, for example, a CCD camera, a CMOS sensor, or a laser scanner, and acquires an image of the surface of the inspection target 500 within its field of view as a visible light image unit. Here, depending on the position at which the visible light imaging device 170 is installed with respect to the terahertz wave imaging head 100, a fixed positional relationship is established between the visible light imaging unit and the terahertz wave imaging unit. The visible light image unit and the terahertz wave image unit are imaged almost simultaneously, and are stored in the memory of the image processing unit 240 as an image unit set. The image processing unit 240 compares the respective visible light image units stored in the memory, and generates a composite image while superimposing the same pattern. The image combining process performed by the image processing unit 240 will be described in detail later.

  Next, a method of using the terahertz wave imaging device according to the first embodiment will be described with reference to FIG. FIG. 2 is a side view showing an example of use of the terahertz wave imaging device according to the first embodiment.

  In FIG. 2, in the terahertz wave imaging apparatus according to the first embodiment, the terahertz wave imaging head unit 100 is configured as a relatively compact handy type head unit. The control / signal processing unit 200 is incorporated in the main unit 300 configured separately from the terahertz wave imaging head 100.

  When the terahertz wave imaging apparatus according to the first embodiment is used, the terahertz wave imaging head 100 may be manually scanned along the surface 501 to be inspected. At this time, the working distance holding unit 180 provided in the terahertz wave imaging head 100 keeps the working distance corresponding to the optical path length of the terahertz wave beam constant. Further, the working distance is adjustable by the working distance adjusting unit 190. Specifically, the working distance adjustment unit 190 is configured as a member capable of adjusting the length in the working distance direction.

  When adjusting the working distance, the size and positional relationship between the acquired terahertz wave image and the visible light image will change. For this reason, when the working distance is adjusted by the working distance adjustment unit 190, the size and the positional relationship between the terahertz wave image and the visible light image are reset in accordance with the adjusted working distance. Alternatively, the visual field magnification is adjusted using a means capable of changing the visual field magnification of the visible light image. Conversely, the working distance can be adjusted by properly setting the relationship between the terahertz wave image and the visible light image according to the working distance.

  In the terahertz wave imaging device, it is possible to obtain information on the internal structure that can not be visually checked, but terahertz waves that can be handled in a configuration that can be practically used for imaging applications are weak. It is necessary to irradiate the inspection target 500. Therefore, the working distance is limited, and the visual field in the depth direction (that is, the optical axis direction) of the inspection object 500 is limited to a narrow range near the focal position of the terahertz wave. Therefore, the fact that the working distance adjustment can be performed while maintaining a substantially constant working distance maintains the image quality of imaging even if the visual field in the depth direction with respect to the test object 500 is changed depending on the position where the object to be examined exists. It has the extremely beneficial effect of being able to

  Next, with reference to FIG. 3 and FIG. 4, composition processing of an image acquired by the terahertz wave imaging apparatus according to the first embodiment will be described. FIG. 3 is a perspective view showing an imaging method in the terahertz wave imaging apparatus according to the first embodiment. FIG. 4 is a conceptual view showing a method of synthesizing a terahertz wave image and a visible light image.

  As shown in FIG. 3, in the terahertz wave imaging apparatus according to the first embodiment, in addition to the terahertz wave imaging unit being acquired using the terahertz wave, the visible light imaging unit 170 is a visible light imaging unit. It is acquired. In general, since the imaging range of the visible light image is wider than the scanning range of the terahertz wave, in the example shown in the figure, the visible light image unit is larger than the terahertz wave image unit. However, the magnitude relationship between the terahertz wave image unit and the visible light image unit is not particularly limited, and the terahertz wave image unit may be larger than the visible light image unit.

  As shown in FIG. 4, the terahertz wave image and the visible light image are acquired as a corresponding set of images. In particular, when a plurality of terahertz wave images are combined to obtain a terahertz wave combined image, a corresponding visible light image is used. Specifically, the terahertz wave image is synthesized using a positional relationship that can be acquired from a visible light image or a visible light combined image obtained by combining a plurality of visible light images.

  Here, due to the characteristics of the terahertz wave image, it is difficult to detect the position from the image itself. On the other hand, visible light images are rich in image processing tools and the like, and it is possible to perform position detection from the image itself to perform synthesis. Therefore, by applying the position information obtained from the visible light image to the corresponding terahertz wave image, it is possible to preferably synthesize the terahertz wave image having no position information.

  In particular, when the head is manually scanned as in the present embodiment, unlike the automatic scanning using, for example, a drive mechanism, it is not possible to acquire information on the imaging position. That is, the imaging position can not be detected mechanically using the driving amount of the driving mechanism or the like. Therefore, when performing a manual scan, the method of acquiring position information using a visible light image as described above is extremely effective.

  The terahertz wave composite image obtained as described above is displayed by the image display unit 250 (see FIG. 1) as an imaging image showing the internal state of the inspection object 500. On the other hand, the visible light combined image is referred to as an imaging image showing the surface state of the inspection object 500.

  In the imaging of the inside of the inspection object 500 which can not be visually checked, a visual image may be used as a reference of the positional relationship and the like. Here, the visible light combined image is a visual image itself, and the inspection image can be confirmed in combination with the visual image by displaying the terahertz wave combined image or displaying it alternately.

  As described above, according to the terahertz wave imaging device according to the first embodiment, the terahertz wave is acquired using the visible light image acquired using the visible light different from the terahertz wave. Terahertz wave images can be properly synthesized. Therefore, imaging using terahertz waves can be performed extremely suitably.

Second Embodiment
Next, a terahertz wave imaging apparatus according to a second embodiment will be described. The second embodiment is different from the above-described first embodiment only in part of the configuration, and the other points are substantially the same. Therefore, in the following, portions different from the first embodiment already described will be described in detail, and description of the other overlapping portions will be appropriately omitted.

  First, the configuration of the terahertz wave imaging apparatus according to the first embodiment will be described with reference to FIG. FIG. 5 is a side view showing a usage example of the terahertz wave imaging apparatus according to the second embodiment.

  In FIG. 5, when using the terahertz wave imaging device according to the second embodiment, the index unit 400 is disposed along the surface 501 to be inspected. That is, the index unit 400 is disposed between the terahertz wave imaging head unit 100 and the inspection object 500. The index part 400 is, for example, a sheet-like or board-like covering, and is made of a material having high terahertz wave transmittance. This can prevent the presence of the index unit 400 from affecting the imaging by the terahertz wave.

  Next, the configuration of the index unit 400 and the composition method using the index unit 400 will be described with reference to FIGS. 6 and 7. FIG. 6 is a plan view showing the configuration of the index portion. FIG. 7 is a conceptual view showing an image combining method using an index unit.

  As shown in FIG. 6, on the surface of the index unit 400, a pattern is drawn such that a unique visible light image can be obtained depending on the position of the terahertz wave imaging head unit 100. In the example shown in the figure, a pattern in which A1 to G8 are arranged in a grid is drawn, but it is a pattern that can be used for detection of position information in a visible light image (that is, a pattern unique to the imaging position) There is no particular limitation if it is.

  In FIG. 7, when the index unit 400 is arranged, a pattern drawn in the index unit 400 is reflected in the plurality of visible light images acquired according to the imaging position. For this reason, different patterns appear in visible light images captured at different positions. As a result, it is possible to improve the accuracy, speed, and stability of processing for detecting position information from a visible light image. Therefore, it becomes possible to more preferably combine the terahertz wave image using the visible light image.

  Generally, nondestructive inspection using terahertz waves is performed when it is desired to know the internal state of the inspection target 500, and thus information on the surface of the inspection target 500 is often not necessary. For example, when it is desired to know the state of the metal under the coating (rust or peeling), the information on the uniform coating surface is not very useful.

  On the contrary, when position detection is performed based on a visible light image as in this embodiment, the difference in visible light image units depending on the position of the terahertz wave imaging head unit 100 is difficult to understand on the uniform coating film surface, and image synthesis etc. Situations may arise where processing is difficult. Even in such a case, by using the index unit 400, visible light images obtained according to the position of the terahertz wave imaging head unit 100 have unique patterns. Therefore, position detection using a visible light image can be reliably performed.

  In addition, although a method of drawing the pattern drawn in the index part 400 directly on the inspection object 500 is also considered, for example, in the inspection of an industrial product or a highly decorative structure for which designability is required, the surface of the inspection object 500 directly Can not draw on. Even in such a case, inspection can be performed by using the index unit 400 so that the terahertz wave imaging head unit 100 does not directly touch the inspection object 500 or by using the index unit 400 slightly floating from the inspection object 500 The subject 500 can be protected.

  Furthermore, when the surface of the inspection target 500 is uneven, etc., when the terahertz wave imaging head unit 100 is scanned, the terahertz wave imaging head unit 100 is caught on the inspection target 500 or the attitude of the terahertz wave imaging head unit 100 Assaults can damage equipment and image quality. In addition, when the terahertz wave imaging head unit 100 is floated and manually scanned, the posture of the terahertz wave imaging head unit 100 is not determined, and the terahertz wave is obliquely applied to the inspection target 500 or the working distance is not determined. Variations in intensity or variations in the field of view of the visible light image lead to image degradation. Even in such a situation, stable scanning can be performed by making the terahertz wave imaging head unit 100 run along the surface using the index unit 400, and imaging can be performed with stable image quality. it can.

  The index part 400 can be produced relatively inexpensively, can be stacked, folded up, spread out, and can be easily carried to the site. In addition, by applying a common index pattern in the peripheral portion of the index portion 400, the work area can be easily expanded.

  As described above, according to the terahertz wave imaging apparatus according to the second embodiment, even in a situation where an appropriate visible light image can not be obtained from the inspection object 500, use of the index unit 400 ensures certainty. Position detection can be performed using a visible light image. Therefore, similarly to the terahertz wave imaging device 1 according to the first embodiment, the terahertz wave image acquired using the terahertz wave can be appropriately synthesized.

  The present invention is not limited to the embodiment described above, and can be suitably modified without departing from the scope or spirit of the invention as can be read from the claims and the specification as a whole, and terahertz wave imaging with such modifications An apparatus and a terahertz wave imaging method are also included in the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 100 terahertz wave imaging head part 110 terahertz wave transmission part 111 terahertz wave generation element 112 silicon lens 113 collimate lens 120 beam splitter 130 beam scanner 140 objective lens 150 terahertz wave receiving part 151 condensing lens 152 silicon lens 153 terahertz wave detection element 160 I -V converter 170 Visible light imaging device 180 Working distance holding part 190 Working distance adjustment part 200 Control and signal processing part 210 Bias generation part 220 Lock-in detection part 230 Scanner drive part 240 Image processing part 250 Image display part 300 Main body part 400 Index part 500 inspection object

Claims (1)

An irradiation unit that irradiates the object with the terahertz wave;
First image acquisition means for detecting the terahertz wave reflected or transmitted by the object and acquiring a first image;
A second image acquisition unit that detects light different from the terahertz wave and acquires a second image;
And t combining means for combining the first image corresponding to the second image.