WO2016142976A1 - Image pickup system - Google Patents

Abstract

This image pickup system that picks up images of terahertz waves is configured by including: a pulsed light source that emits infrared to terahertz waves; a camera that picks up images by driving an image pickup sensor; a pulse control unit that generates a first trigger pulse that determines light emitting timing of the pulsed light source, and a second trigger pulse that determines image pickup timing of the camera. The pulse control unit is operated such that the first trigger pulse is outputted to the pulsed light source, and the second trigger pulse is outputted to the camera earlier than the first trigger pulse.

Description

Imaging system

The present invention relates to an imaging system having an imaging band from the infrared region to the terahertz region, and more particularly to an imaging system including a light source device that emits light from the infrared region to the terahertz region and a camera that images the terahertz region from the infrared region. .

Today, development of an imaging system using an imaging band from an infrared region to a terahertz region (hereinafter referred to as a THz band or a terahertz band) is in progress. The THz band cannot be satisfactorily captured by current radio wave observation technology and visible light imaging technology. On the other hand, sensing in the THz band has an advantage that information that does not exist in other frequency regions can be obtained.

For example, in imaging in the THz band, an image (so-called lock-in) that excludes the influence of electromagnetic waves other than the frequency band of the light source by repeatedly turning on and off the light source and acquiring a captured image with the camera in synchronization with the lighting period of the light source. Image). With this lock-in image using THz waves, it is possible to obtain transmission images and reflection images of various objects (for example, paper and smoke). The THz band imaging technique has many objects that do not transmit, and can be used for various applications depending on the difference between the transmitted object and the non-transmitted object.

Related techniques include Patent Documents 1 and 2.

The imaging systems described in Patent Documents 1 and 2 include a THz band light source, a camera that captures THz waves, and an image processing device, and image an imaging target in an optical path.

In the technique described in Patent Document 1, the imaging system supplies a light source pulse signal according to the timing obtained by multiplying the synchro signal output from the camera to 1 / n times to a driving circuit that drives the light source, and the light emission period of the light source And the imaging period of the camera (including the light emission period and the non-light emission period of the light source) are synchronized. In addition, the imaging system captures a large number of images when the light source emits light during the light emission period synchronized with the imaging period and a large number of images when the light source does not emit light during the non-light emitting period, Image processing is performed to generate a desired image. In this image processing, the image processing device subtracts the image information of the same number of images at the time of non-light source emission from the image information of a large number of images at the time of light source emission, and integrates the obtained difference images for sharpening. The desired image is obtained.

Also, the technique described in Patent Document 2 provides an imaging method in which the light emission period of a drive circuit that drives a light source can be independent without depending on a camera sync signal. In this method, the imaging system collects a group of images captured by a camera over a plurality of frames, and collects pixels having the maximum image intensity for each pixel from the images of the individual frames to generate one image. By this method, a clear image can be generated even if the cycle of the light emission period of the light source is different from the imaging frame cycle of the camera (internal circuit).

Cameras capable of imaging the THz band include a terahertz camera (product model number: IRV-T0831) developed by the applicant, and the Pyrocam ( ^TM ) series of Offiel. Both cameras are uncooled infrared and terahertz cameras. Further, the array sensor of the terahertz camera developed by the applicant is a bolometer type and has good sensitivity characteristics. Non-Patent Document 1 is a user guide (manual) of Pyrocam IV. Pyrocam IV has a function capable of sensing with an exposure time (exposure timing) synchronized with an external trigger in response to an external trigger input.

JP 2012-205217 A (Patent No. 5305482) JP 2014-160919 A

The inventors are making progress in imaging systems using the terahertz band (THz band) every day. On the other hand, as further technical improvements, we will seek to clarify the acquired images and pursue real-time performance.

In pursuing the above improvements, we will focus on optimizing the scan start timing of the image sensor in the camera and the light emission timing of the light source as technical issues. It is also conscious of the characteristics of the image sensor such as scan time (exposure time) and sensor sensitivity.

The imaging systems described in Patent Document 1 and Patent Document 2 try to generate a clear image by combining a large number of captured images.
On the other hand, the imaging systems described in Patent Document 1 and Patent Document 2 require an imaging period (time) for obtaining a predetermined amount of image groups used for composition. In other words, the imaging system can output the generated image only after a predetermined imaging period (time) has elapsed since the imaging was started. For this reason, the imaging method disclosed in Patent Literature 1 and Patent Literature 2 can be set with a problem of improving the real-time property.

The clarification of the acquired image includes an approach of synthesizing a clear image from a large number of captured images as in the above method, and an approach of clarifying each captured image itself.

If the individual captured images themselves are clarified, the imaging system can display clear captured images without waiting for acquisition of a large number of images. In addition, the approach of synthesizing a clear image from a large number of captured images can be favorably influenced.

The sharpness of each image varies greatly depending on the light source (pulsed light), camera (imaging sensor; array sensor), imaging condition (usage frequency band, etc.), and the like.
Among these, the performance of the camera is important. The camera was able to improve the sensitivity of the camera by changing the structure of the array sensor to widen the interference length. In addition, the sensitivity of the camera can be enhanced by a mechanism that takes a long exposure time. On the other hand, it is not clear how the exposure time can be increased according to the pulsed light.

In addition, an array sensor having a thermal time constant has a characteristic that the sensitivity of the output signal value decreases over time with the passage of time from the start of operation (the moment when the drive pulse is received). If the thermal time constant of the array sensor is small, the effect of this time-dependent decrease in sensitivity becomes greater.
Therefore, in this type of array sensor, if the exposure possible section is long, the influence of the output signal value over time due to the difference in the actual exposure timing within the exposure possible section becomes large.
In other words, the output signal value output from the array sensor varies greatly depending on whether the pulse light is received from the early stage of the exposure possible section or the pulse light is received from the late stage of the exposure possible section.

Also, the distance between the light source and the array sensor (optical path length: propagation distance) is likely to change depending on the imaging conditions. For this reason, it is difficult to measure the sensing timing of the array sensor.

If we point out the problems arising from many complex matters, it can be said that it is difficult to stably align the incident timing of the pulsed light from the light source and the good imaging timing of the camera. For this reason, in the image acquisition of the existing technology, variations may occur in individual acquired images. As a result, the satisfactory sensitivity characteristics of the camera could not be exhibited.

The present invention provides an imaging system, an imaging method, and a recording medium that include a terahertz region in an imaging band, pursuing real-time characteristics while clarifying an acquired image based on the above-mentioned many matters.

An imaging system according to the present invention includes a pulse light source that emits infrared rays or terahertz waves, a camera that drives an imaging sensor to capture an image, a first trigger pulse that determines the light emission timing of the pulse light source, and the imaging timing of the camera. A pulse control unit that generates a second trigger pulse to be determined, and the pulse control unit outputs the first trigger pulse to the pulse light source, and precedes the first trigger pulse. The second trigger pulse is output to the camera.

A pulse control device according to an embodiment of the present invention includes a first trigger pulse that determines a light emission timing of a pulse light source that emits infrared rays or terahertz waves, and a second trigger that determines an imaging timing of a camera that drives and images an image sensor. A pulse generator for generating a trigger pulse, and an output unit for outputting the first trigger pulse to the pulse light source and outputting the second trigger pulse to the camera prior to the first trigger pulse. It is characterized by having.

A camera according to an embodiment of the present invention includes an imaging sensor that detects infrared rays or terahertz waves, and a pulse control unit that generates a trigger pulse that determines the light emission timing of a pulse light source that emits infrared rays or terahertz waves. The pulse control unit outputs the trigger pulse to the pulse light source while determining an exposure timing of the imaging sensor that precedes a set value time from a timing of outputting the trigger pulse.

An imaging method according to an embodiment of the present invention is an imaging system including a pulse light source, a camera, and a pulse control unit, and emits infrared or terahertz waves from the pulse light source at a pulse interval received from the pulse control unit. The image sensor is driven to obtain an image to be captured at a pulse interval received from the pulse control unit, and the pulse control unit determines a light emission timing of the pulse light source and the first trigger pulse and the infrared and terahertz camera. And outputting a second trigger pulse for determining the imaging timing. At this time, the second trigger pulse is generated prior to the first trigger pulse at a set time, and the first trigger pulse is generated. The trigger pulse is output to the pulse light source, and the second trigger pulse is output to the camera prior to the first trigger pulse. It is characterized in.

In a recording medium according to an embodiment of the present invention, a control unit of an information processing device determines a first trigger pulse that determines a light emission timing of a pulse light source that emits infrared rays or terahertz waves and an imaging timing of an infrared / terahertz camera. A pulse generation unit that generates the second trigger pulse before the first trigger pulse, and generates the second trigger pulse with a set time interval; the first trigger pulse and the second trigger pulse; It is characterized by operating as a pulse output section for outputting each trigger pulse.

According to the present invention, it is possible to provide an imaging system, an imaging method, and a recording medium having an imaging band including a terahertz region that improves the real-time property while clarifying an acquired image.

1 is a configuration diagram illustrating an imaging system 1 according to a first embodiment. It is a lineblock diagram showing the modification of imaging system 1 concerning a 1st embodiment. It is the timing chart which modeled the relationship between a light source pulse signal and an external trigger pulse signal. It is a timing chart explaining the mechanism which adjusts the range of the time difference of a light source pulse signal and an external trigger pulse signal. It is another timing chart explaining the mechanism which adjusts the range of the time difference of a light source pulse signal and an external trigger pulse signal. It is a block diagram which shows the imaging system 2 which concerns on 2nd Embodiment. It is a block diagram which shows the modification of the imaging system 2 which concerns on 2nd Embodiment. It is a block diagram which shows the imaging system 3 which concerns on 3rd Embodiment. It is a block diagram which shows the imaging system 4 which concerns on 4th Embodiment. It is the timing chart which modeled the relationship of a light source pulse signal, an external trigger pulse signal, and the internal signal in a camera. It is the figure which modeled the beam pattern image | photographed with the imaging system. 3 is a block diagram illustrating a configuration example of a pulse control unit of the imaging system 2. FIG.

Embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a configuration diagram illustrating an imaging system 1 according to the first embodiment. FIG. 2 is a configuration diagram illustrating a modified example of the imaging system 1 according to the first embodiment.

The imaging system 1 shown in FIGS. 1 and 2 includes a light source device 10, a camera 11, and a pulse control unit 12. The devices are connected with cables as necessary. Each device may be configured by wireless connection. The system configuration shown in FIG. 1 is an arrangement used for developing a laser light source. In addition, in this system configuration, if a subject to be photographed is arranged in the optical path, photographing in the transmission mode is possible. The system configuration shown in FIG. 2 is an arrangement used for observation of an object to be photographed in the reflection mode.

The light source device 10 emits infrared rays or terahertz waves at the pulse interval of the light source pulse signal received from the pulse control unit 12. The frequency band to emit light may be appropriately determined according to the measurement object and various conditions. As the light source device 10, for example, a free electron laser device can be used. The structure of the light source device 10 is not particularly limited as long as the light source device 10 emits infrared rays or terahertz waves at received pulse intervals.

The camera 11 drives the imaging sensor 13 at the pulse interval of the external trigger pulse signal received from the pulse control unit 12. The driven imaging sensor 13 senses infrared rays and terahertz waves emitted from the light source device 10. Thus, the camera 11 operates the imaging sensor 13 according to the external trigger. This fine adjustment of the imaging operation will also be described later. Further, it is desirable that the camera 11 can set the drive stop timing of the image sensor 13. The camera 11 outputs the captured image to a monitor or a computer.

The pulse control unit 12 generates a light source pulse signal that determines the light emission timing of the pulse light source and an external trigger pulse signal that determines the imaging timing for the camera as a first trigger pulse and a second trigger pulse, respectively, and the light source device 10 And output to the camera 11, respectively. At this time, the pulse controller 12 generates a light source pulse signal sequence and an external trigger pulse signal sequence with a periodicity having an external trigger pulse signal in a period preceding the light source pulse signal. The pulse control unit 12 may generate the single light source pulse signal and the external trigger pulse signal by opening the second trigger pulse for a predetermined time prior to the first trigger pulse. Further, the pulse control unit 12 may generate both pulse signal sequences for the interval between the light source pulse signal and the external trigger pulse signal according to the set value given by the user. This set value may be set automatically / semi-automatically as will be described later.

The pulse control unit 12 may have any configuration as long as each clock pulse signal is synchronized with each other and both pulse trains can be generated with a time difference between set values. For example, it may be configured by a clock generator device having a plurality of clock generator functions, a microcomputer board that can adjust a pulse signal sequence by a microcomputer, or an electronic circuit.

Next, the operation of the imaging system 1 will be described.

FIG. 3 is a timing chart schematically illustrating the relationship between the light source pulse signal and the external trigger pulse. (B) in the figure is an enlarged view of (a).
T1 shown in the figure is a time interval according to a set value given by the user.
This t1 indicates the preceding time of the external trigger pulse signal with respect to the light source pulse signal. The sensor drive instruction cycle (t2) and the light emission instruction cycle (t2) in the figure are basically the same cycle. This period (t2) may be appropriately determined according to the light source to be used, the measurement target, and the like. For the sake of explanation, the side preceding the time (left direction) is taken as a positive value, and the side lagging as time (right direction) is taken as a negative value. The imaging system 1 may be configured to accept a set value of t1 as a negative value from the user. This negative region of t1 is easy to use effectively when the arrival delay amount of the terahertz wave is large.

The pulse controller 12 generates and outputs a light source pulse signal and an external trigger pulse signal periodically (see t2 in FIG. 3). At this time, the interval (t1) between the light source pulse signal and the external trigger pulse signal is generated with a periodicity having the external trigger pulse signal in the period preceding the light source pulse signal according to the set value.
The light source device 10 receives the generated light source pulse signal sequence and emits a terahertz wave having a predetermined pulse width at the pulse interval. The camera 11 receives the generated external trigger pulse signal sequence and drives the image sensor 13 at the pulse interval. The terahertz wave pulse width transmitted from the light source device 10 may be the same as or different from the width of the light source pulse signal. This pulse width may be appropriately determined according to the measurement object. FIGS. 3B and 4A described later are examples in which the pulse widths of the light source pulse signal and the terahertz wave coincide with each other. 4B, 5A, and 5B are examples in which the light emitting device 10 emits a terahertz wave having a pulse width longer than that of the light source pulse signal. Alternatively, a terahertz wave having a pulse width shorter than that of the light source pulse signal may be emitted.

Each device in the system performs the above operation, so that the incident timing of the pulsed light from the light source device 10 and the good imaging timing of the camera 11 can be stably aligned.

The timing and period when the camera 11 drives the image sensor 13 is preferably such that the light (pulse light) from the light source of the light source device 10 falls within one reading time (one frame) of the camera 11. Further, at this timing, it is desirable to drive the image sensor 13 before the light (pulse light) from the light source of the light source device 10 arrives.
For this reason, it is desirable that the camera 11 includes a configuration in which the timing for driving and stopping the imaging sensor 13 is adjusted based on the external trigger pulse. Specifically, it is desirable that the camera 11 starts the timing for driving the image sensor 13 between the external trigger pulse signal and the light source pulse signal, that is, within the period t1 shown in FIG.

The camera 11 may appropriately drive the image sensor 13 according to the sensor type. For example, in the case of a bolometer-type uncooled infrared / terahertz camera, a bias voltage used for scanning of the array sensor may be applied after a predetermined time has elapsed after receiving the external trigger pulse signal. In the infrared / terahertz camera, the scanning position may be initialized at this timing. The predetermined time is desirably a value at which application of the bias voltage is started within t1 time with reference to the external trigger pulse signal. In addition, the infrared / terahertz camera preferably includes a mechanism for automatically stopping the application of the bias voltage after scanning by the array sensor. This stop timing may be determined by allowing the user to input a scanning period (time), or may have some values as setting values of the camera 11 in advance.

It should be noted that the values of t1 and t2 may be input by the user to the camera 11, or the pulse control unit 12 may be notified via a wired or wireless connection.

With this configuration and operation, the imaging system 1 can improve the real-time property while clarifying the acquired image.

Here, some adjustment mechanisms for generating the light source pulse signal and the external trigger pulse signal of the pulse controller 12 will be described. Although it is not necessary to have all the mechanisms described below, the convenience of the system is enhanced by having many mechanisms.

[Adjustment mechanism 1. ]
The pulse control unit 12 may have a mechanism for adjusting a set value input range that determines a time difference between the pulse signal sequences (the above-described t1) based on the driving time of the camera 11. The driving time of the camera 11 may be set in another way even if a value from the time when the camera 11 receives a trigger to the start of scanning or a value of an apparatus limit (the shortest time from driving instruction by trigger to driving the image sensor) is used. You may use the value determined from. In this mechanism, the pulse control unit 12 adopts only a value larger than the driving time of the camera 11 (t3 in FIG. 4) as the value of t1. In other words, the range of the time difference between the pulse signals (set value input range) is within the range of t1 ′ in the figure by operating this mechanism.

The specific configuration may be, for example, limiting the range of t1 values received from the user by calculating from the value of t3 within the pulse control unit 12, or returning an error to the user. Further, the pulse control unit 12 may be provided with an automatic adjustment function (adjustment function) so that the setting whose user set value is within t3 is automatically updated to the lower limit of t1 '(position adjacent to t3).

By providing this mechanism, it is possible to ensure that the camera 11 (sensor) is driven before the light from the light source reaches, and the convenience of the entire system increases.

[Adjustment mechanism 2. ]
The pulse controller 12 receives an input of a terahertz wave pulse width value (one pulse emission time), and a light source pulse signal according to the terahertz wave pulse width (t4, terahertz wave emission period in FIG. 4) emitted from the pulse light source. There may be a mechanism for limiting the set value that defines the interval (t1) between the external trigger pulse signal and the external trigger pulse signal to a value within one cycle (t5) excluding the terahertz wave width based on the light source pulse signal.

For example, as an automatic adjustment function (adjustment function), when the relationship between the values of t1 and t2 and the terahertz wave width value (time) t4 becomes inconsistent, an error is returned to the user or the allowable range The user set value may be automatically updated to the value within. The terahertz wave width value may be configured to receive an input from the user, or may be configured to acquire the value from the light source device 10. Further, the imaging system may be configured such that the camera 11 has a mechanism for actually measuring the terahertz wave width, and the pulse control unit 12 acquires the actually measured value (the terahertz wave emission period) via a wire or wirelessly.

By providing this mechanism, even when the terahertz wave width irradiated from the light source of the light source device 10 is long with respect to each time interval, the camera 11 (sensor) before the arrival of one pulse of light from the light source and after the disappearance of the previous one pulse. ) Can be secured and the convenience of the entire system is increased.

[Adjustment mechanism 3. ]
The pulse control unit 12 receives the input of the terahertz wave arrival delay time (value), and according to the arrival delay time of the terahertz wave irradiated from the pulse light source (t6 in FIG. 5), the light source pulse signal and the external trigger pulse signal There may be a mechanism for limiting the set value for determining the interval (t1) to a value within one period (t7) excluding the delay time (t6) with reference to the light source pulse signal. Moreover, even if it is a case where negative t1 is received from a user, what is necessary is just to share an allowance area between the periods before and behind. Further, if the terahertz wave width (t4) is input, the pulse control unit 12 sets the interval (t1) between the light source pulse signal and the external trigger pulse signal to the total time of the terahertz wave width (t4) and the delay time (t6). It may be set to a value within one cycle (t8) excluding.

The arrival delay time of terahertz waves is affected by the optical path length. The arrival delay time is affected by the time from when the light source device 10 receives the light source pulse signal until when the terahertz wave is actually emitted. Although this arrival delay time is unknown or may be negligible, it essentially exists. For this arrival delay time, it is desirable to prepare in advance several values as selectable values in addition to the input of the assumed value by the user. Further, a system configuration may be adopted in which the light emission delay time and the propagation delay time of the light source device 10 are separately received as set values.

The specific configuration is, for example, as an automatic adjustment function (adjustment function), when the relationship between the values of t1, t2, t4, and t6 becomes inconsistent, an error is returned to the user, or the value is within the allowable range. The set value may be automatically updated. The value of t6 may be configured to accept an input from the user as one value, or may accept individual values divided into a plurality of values such as a light emission delay time and a propagation delay time. Further, the configuration may be such that the propagation path type, the optical path distance and the distance to the object to be imaged are received from the user, such as in a gas or an arbitrary medium, and the corresponding selectable value is automatically selected. Further, the camera 11 may be provided with a mechanism for observing the terahertz wave pulse width, and the system may be configured so that the pulse controller 12 acquires the value.

By providing this mechanism, even when the delay time until the terahertz wave irradiated from the light source reaches the camera 11 is long, the camera 11 (sensor) before the arrival of one pulse of light from the light source and after the disappearance of the previous one pulse. ) Can be secured and the convenience of the entire system is increased.

[Adjustment mechanism 4. ]
The adjustment mechanism 1. , 2. , 3. The mechanisms can be combined. FIG. 5B is a timing chart when the mechanisms are combined. In addition, for example, the above 1. And 2. Or a combination of the above 1. , 3. , 2. And 3. As long as it is a combination, it may be combined freely as appropriate. The adjustment mechanism 1. , 2. , 3. As a result, the pulse control unit 12 obtains a mechanism for limiting the interval (t1) between the light source pulse signal and the external trigger pulse signal within the set input range in t8 ′ in the figure. . Alternatively, the user set value may be automatically updated to the lower limit of t8 ′ (position adjacent to t3) using the automatic adjustment function of the pulse control unit 12. The lower limit of t8 ′ shown in FIG. 5B corresponds to a position where the t1 set value takes a negative value.

By providing the above adjustment mechanism, it is ensured that the pulsed light source arrives within the readout time of the camera 11, and imaging is started stably and stably at the timing at which the sensitivity of the camera 11 (sensor) can be maximized. It becomes possible to do.

[Second Embodiment]
6 and 7 are configuration diagrams showing the imaging system 2 according to the second embodiment.

The imaging system 2 shown in FIGS. 6 and 7 includes a light source device 10, a camera 11, and a computer 14 that operates as pulse control means. The devices are connected with input / output interfaces and cables as necessary. Each device may be configured by wireless connection. The system configuration shown in FIG. 6 is an arrangement used for laser light source development. In addition, in this system configuration, if a subject to be photographed is arranged in the optical path, photographing in the transmission mode is possible. The system configuration shown in FIG. 7 is an arrangement used for observation of an object to be photographed in the reflection mode. Since the description of the light source device 10 and the camera 11 has been described in the first embodiment, the description is simplified.

The computer 14 (processor) is responsible for the pulse control unit 12 of the first embodiment. The computer 14 also operates as a monitor that displays a sensing image received from the camera 11 via the input interface. The computer 14 may also operate as a database by storing images in an internal storage device. Further, the computer 14 may operate to send an image to a server or an external storage device via a communication interface. The computer 14 may perform image processing for obtaining a clarified image from a plurality of images.

The computer 14 generates a light source pulse signal that determines the light emission timing of the pulse light source and an external trigger pulse signal that determines the imaging timing for the infrared and terahertz band cameras, and outputs the output interfaces to the light source device 10 and the camera 11 respectively. Respectively. At this time, the pulse control unit of the computer 14 generates a light source pulse signal and an external trigger pulse signal with periodicity having an external trigger pulse signal in a period preceding the light source pulse signal based on the set value.

Further, the computer 14 may generate both pulse signal sequences for the interval between the light source pulse signal and the external trigger pulse signal according to the set value given by the user. The computer 14 may accept the setting value from the user via a keyboard or a graphical user interface (input interface). For this set value, the computer 14 may include the adjustment mechanism described above, and the set value may be set automatically / semi-automatically.

The computer 14 may have any configuration as long as the processor can be operated to synchronize the clock pulse signals with each other and generate both pulse trains with a set time difference. In one example, an application program may be created by combining pulse control programs that operate on a basic OS (Operating System). The computer 14 may develop this application program in a memory to form a pulse control unit.

Further, it may be combined with a program for analyzing an image group received from the camera 11 (for example, disclosed techniques of Patent Documents 1 and 2). A desired image may be acquired by driving the processor of the computer 14 based on this program.

With this configuration and operation, the imaging system 2 can improve real-time characteristics while clarifying an acquired image.
Also, input of each set value, storage / display of acquired images, image clarification processing (various image filters, clarification by multiple images, color change, etc.), camera and light source adjustment, etc. are integrated on a graphical user interface It is also easy to do.

[Third Embodiment]
FIG. 8 is a configuration diagram illustrating the imaging system 3 according to the third embodiment.

The imaging system 3 shown in FIG. 8 includes a light source device 10, a camera 11, and a computer 14 that operates as pulse control means, as in the second embodiment. The imaging system 3 of the present embodiment irradiates one pulse of terahertz wave from the light source device 10 and observes the one pulse of terahertz wave with the camera 11. The system configuration shown in FIG. 8 is an arrangement used for observation of an object to be photographed in the reflection mode. Of course, you may arrange | position so that imaging | photography by transmission mode may be performed. Note that the description of the components already described in the previous embodiment is omitted or simplified.

The computer 14 generates a light source pulse signal that determines the light emission timing of the pulse light source and an external trigger pulse signal that determines the imaging timing for the infrared and terahertz band cameras, and outputs them to the light source device 10 and the camera 11, respectively. At this time, the pulse control unit of the computer 14 generates a light source pulse signal and an external trigger pulse signal one pulse at a time before setting the external trigger pulse signal before the light source pulse signal.

Also, the computer 14 may generate both the light source pulse signal and the external trigger pulse signal according to the timing given by the user. Further, the system configuration may be such that a user other than the user, for example, receives a pulse generation instruction (imaging instruction) from another computer or the like.

With this configuration and operation, the imaging system 3 can improve the clarity of the acquired image by one pulse wave.

[Fourth Embodiment]
FIG. 9 is a configuration diagram illustrating an imaging system 4 according to the fourth embodiment.

The imaging system 4 shown in FIG. 9 has a configuration in which a pulse control unit is provided in the camera 15. The imaging system 4 of the present embodiment generates a trigger pulse (light source pulse signal) that determines the light emission timing of the light source device 10 in the camera 15 (pulse control unit). Further, the camera 15 irradiates the imaging target with one pulse of terahertz wave from the light source device 10 and observes the one pulse of terahertz wave. The system arrangement may be in reflection mode or transmission mode. Note that the description of the components already described in the previous embodiment is omitted or simplified.

The camera 15 includes an imaging sensor 13 that detects infrared rays or terahertz waves, and a pulse control unit. Further, an image processing unit (for image clarification), an output unit (output interface), and a monitor unit may be provided in the camera 15 as necessary.

The pulse control unit of the camera 15 sets the trigger pulse to be output to the light source device 10 and the exposure timing of the image sensor 13 that precedes the set time from the timing at which this trigger pulse is output in a synchronized state.

Further, the camera 15 may generate the light source pulse signal according to the timing given by the user, or may generate it in accordance with a desired imaging timing (for example, imaging frame rate).

With this configuration and operation, the imaging system 4 can enhance the clarity of the acquired image for each pulse wave or each pulse wave.

[Example]
Next, an embodiment will be shown to explain the present invention.

The system configuration of this embodiment is the same as that shown in FIG.
The camera 11 of the present embodiment uses a high-sensitivity bolometer type infrared / terahertz camera provided with an interface for receiving an external trigger pulse signal. This high-sensitivity bolometer type infrared and terahertz camera is equipped with a terahertz array sensor (two-dimensional bolometer array), and the noise equivalent power of each pixel is as high as about 30 pW. As the light source device 10, a quantum cascade laser that emits light according to an input pulse signal sequence is used.
The pulse control unit 12 outputs a light source pulse signal and an external trigger pulse signal in a state where the light source device 10 and the camera 11 are connected to each other by a wired cable via an interface.

Camera 11 (in-camera controller) drives the array sensor using a horizontal synchronization clock and a vertical synchronization clock as internal signals for scanning. The camera 11 is configured so that the horizontal synchronization clock is continuously sent until this synchronization signal is received, and the vertical synchronization clock is not sent until the external trigger pulse signal is received. Note that the relationship between the vertical synchronization clock and the horizontal synchronization clock may be reversed.

The timing for applying the pulse bias to the array sensor is adjusted by not sending this vertical synchronization clock to the array sensor until the predetermined scan timing.

When scanning according to the external trigger pulse signal, the camera 11 sends a short vertical synchronization clock after a predetermined time so that each pixel signal can be read, and then sends a vertical clock having a length of one frame to send each pixel signal. Is read. Thereafter, the camera 11 stops the vertical synchronization clock at the end of reading out the pixel signal, and stops reading out the pixel signal (pulse bias) until the next scan timing.

Also, the camera 11 has a step of resetting the scan position of the array sensor to the start address of the scan immediately after receiving the external trigger signal.

In this way, the camera 11 reads the output signal value group of each pixel of the array sensor and forms one image when the predetermined scan timing is reached.

Cameras equipped with array sensors with relatively large thermal time constants, such as high-sensitivity bolometer-type infrared and terahertz cameras, often have a thermal separation structure in each pixel of infrared and terahertz array sensors. ing. The thermal time constant of this type of array sensor is generally in the range of 5 ms to 20 ms.

In the array sensor, infrared rays or terahertz waves incident on each pixel are absorbed by the light receiving unit. As a result, the temperature of the bolometer material arranged in the light receiving portion changes and its resistance value changes. This resistance change is read out by applying a bias voltage.

When reading out this resistance change by applying a bias voltage, if a DC bias is applied, the element may be destroyed by Joule heat. In an uncooled image sensor, a pulse bias is often applied to avoid destruction.

The timing at which the pulsed terahertz wave and the scan are detected in synchronization using such a camera having a relatively large time constant will be described with reference to the timing chart shown in FIG.

The pulse control unit 12 generates a light source pulse signal and an external trigger pulse signal according to the input set value, and outputs them to the light source device 10 and the camera 11.

The light source device 10 emits light according to the light source pulse signal. The light emission delay time is ignored in this embodiment.

At this time, in the camera 11, a reset pulse is generated by the controller at the rising edge of the external trigger pulse signal in synchronization with the clock signal, and the scan setting of the camera is reset (the scanning position of the bolometer array is set to the head address of the pixel). To return). After that, the camera 11 generates a vertical synchronization protection release pulse in the vertical synchronization signal (V _IN ) by the controller so that the array sensor can be read out, and then scans after a predetermined clock elapses. During this scan, a light source pulse is emitted from the light source device 10 and reaches the camera 11.

By operating in this way, pulsed electromagnetic waves can be stably detected by the camera 11 equipped with a high-sensitivity bolometer type array sensor. As a result, the imaging system can acquire the terahertz wave emitted from the terahertz wave source as a clear and almost real-time image.

FIG. 11 is a schematic diagram of a beam pattern photographed by the mechanism of the present invention.

This figure shows an image that captures the beam pattern of a free electron laser. This image imitates one image when each image is acquired by setting the scan frame rate of the camera 11 to 30 Hz.

Further, “A” in FIG. 10 (time from the generation of the external trigger pulse signal to the start of sensing) is 0.15 msec, and “B” (the light source is emitted after the generation of the external trigger pulse signal). Time) was set to 1 msec, and “C” (sensing time synchronized with the external trigger pulse signal) was set to 33 msec.

Also, the thermal time constant of the pixels of the bolometer array used to acquire the image is “about 19 msec”. Therefore, if the light source pulse has reached the vicinity of the center of the array sensor, even if the head address of the scanning point of the image is in the upper left pixel of the screen, it is good until the scanning address advances to the vicinity of the center of the screen. Sensitivity can be maintained. That is, by performing initialization with the reset signal, the temporal decrease in the output signal value of the array sensor due to the thermal time constant can be maintained stably and slightly.

In this way, the noise is increased by realizing a mechanism in which the external trigger pulse signal precedes the light source generation pulse signal in time and the pulse light source reaches the readout time of each frame of the camera 11. The electromagnetic wave from the pulse light source can be captured clearly and stably.

Note that each part of the computer 14 that operates as a pulse control unit has the program according to the present invention developed in a memory, and operates each piece of hardware as a CPU (Central Processing Unit) based on the program. Realize. Further, this program may be recorded non-temporarily on a recording medium and distributed. The program recorded on the recording medium is read into a memory via a wired, wireless, or recording medium itself, and operates a control unit or the like. Examples of the recording medium include an optical disk, a magnetic disk, a semiconductor memory device, and a hard disk.

If the above embodiment is described in another expression, a computer system that operates as a pulse control unit, based on the program of the present invention developed in a memory, a pulse signal generation unit that outputs each of two trigger pulses, and its It can also be realized by operating a processor as a pulse output unit for outputting each trigger pulse. FIG. 12 is a configuration diagram illustrating an example of a pulse control unit. The algorithm of the adjustment mechanism may be incorporated in the pulse output unit or may be incorporated in the pulse signal generation unit.

Although the embodiments and examples have been illustrated and described above, changes such as separation / merging of block configurations and replacement of procedures are free as long as the gist of the present invention and the functions to be described are satisfied. It is not limited.

In addition, the specific configuration of the present invention is not limited to the above-described embodiment, and changes within a range not departing from the gist of the present invention are included in the present invention.

In addition, a part or all of the above-described embodiments can be described as follows. Note that the following supplementary notes do not limit the present invention.
[Appendix 1]
A pulsed light source that emits infrared or terahertz waves;
A camera for imaging by driving an imaging sensor;
A pulse control unit for generating a first trigger pulse for determining the light emission timing of the pulse light source and a second trigger pulse for determining the imaging timing of the camera;
Have
The imaging system, wherein the pulse control unit outputs the first trigger pulse to the pulse light source, and outputs the second trigger pulse to the camera prior to the first trigger pulse.

[Appendix 2]
The pulse control unit periodically generates the first trigger pulse and the second trigger pulse, and synchronizes the cycle of the first trigger pulse and the cycle of the second trigger pulse, respectively, The imaging system according to the above supplementary note, wherein the imaging system outputs to a pulse light source and the camera.

[Appendix 3]
The pulse control unit sets an interval between the first trigger pulse and the second trigger pulse to a set value when outputting the first trigger pulse or the second trigger pulse. The imaging system according to the above supplementary note, which is characterized.

[Appendix 4]
The pulse control unit is a set value that determines an interval between the first trigger pulse and the second trigger pulse based on a period from when the camera receives the second trigger pulse to when scanning is started. The imaging system according to the above supplementary note, wherein:

[Appendix 5]
The pulse control unit sets a set value for determining an interval between the first trigger pulse and the second trigger pulse as one preceding cycle excluding a light emission period of the pulsed light source based on the first trigger pulse. The imaging system according to the above supplementary note, wherein the imaging system is set within a range.

[Appendix 6]
The pulse control unit is configured to change an interval between the first trigger pulse and the second trigger pulse from one cycle of the first trigger pulse based on a light emission period of the pulse light source measured by the camera. The imaging system according to the above supplementary note, wherein the imaging system is set within a time excluding the light emission period.

[Appendix 7]
The pulse control unit sets a setting value for determining an interval between the first trigger pulse and the second trigger pulse according to an arrival delay time until the infrared or terahertz wave from the pulse light source reaches the camera. The imaging system according to the above supplementary note, wherein the imaging system is set within a period excluding the arrival delay time with reference to the first trigger pulse.

[Appendix 8]
The above-described remarks, wherein the camera receives the second trigger pulse, and applies a bias voltage used for scanning of the imaging sensor for a predetermined period after a predetermined period has elapsed from the second trigger pulse. Imaging system.

[Appendix 9]
The imaging system according to the above supplementary note, wherein the camera receives the second trigger pulse and sets the scanning position of the imaging sensor to an initial position at a timing according to the second trigger pulse.

[Appendix 10]
The imaging system according to the above supplementary note, wherein the camera starts scanning of the imaging sensor during a period from the transmission of the second trigger pulse to the transmission of the first trigger pulse.

[Appendix 11]
A pulse generator that generates a first trigger pulse that determines the light emission timing of a pulse light source that emits infrared rays or terahertz waves, and a second trigger pulse that determines the imaging timing of a camera that drives and images the imaging sensor;
The pulse control device further comprising: an output unit that outputs the first trigger pulse to the pulse light source and outputs the second trigger pulse to the camera prior to the first trigger pulse.

[Appendix 12]
The first trigger pulse and the second trigger pulse are periodically generated, and the period of the first trigger pulse and the period of the second trigger pulse are synchronized to each of the pulse light source and the camera. The pulse control device as described in the above supplementary note, which outputs the pulse control device.

[Appendix 13]
When the first trigger pulse or the second trigger pulse is output, an interval between the first trigger pulse and the second trigger pulse is set to a set value. Pulse control device.

[Appendix 14]
A setting value for setting an interval between the first trigger pulse and the second trigger pulse is set based on a period from when the camera receives the second trigger pulse to when scanning is started. The pulse control device according to the above supplementary note.

[Appendix 15]
Setting a set value for determining an interval between the first trigger pulse and the second trigger pulse within one preceding cycle excluding a light emission period of the pulse light source with reference to the first trigger pulse. The pulse control device according to the above supplementary note, which is characterized by the above.

[Appendix 16]
Based on the light emission period of the pulsed light source measured by the camera, the interval between the first trigger pulse and the second trigger pulse is excluded from one period of the first trigger pulse. The pulse control device according to the above supplementary note, which is set within the time.

[Appendix 17]
A set value that determines an interval between the first trigger pulse and the second trigger pulse in accordance with an arrival delay time until an infrared ray or terahertz wave from the pulse light source reaches the camera is set as the first trigger pulse. Is set within a period excluding the arrival delay time with reference to

[Appendix 18]
An imaging sensor for detecting infrared or terahertz waves;
A pulse controller that generates a trigger pulse that determines the light emission timing of a pulse light source that emits infrared or terahertz waves;
Including
The said pulse control part outputs the said trigger pulse to the said pulse light source, determining the exposure timing of the said image sensor which preceded the time of setting value from the timing which outputs the said trigger pulse.

[Appendix 19]
The pulse control unit sets a set value for determining an interval between the trigger pulse and the exposure timing within one preceding cycle excluding a light emission period of the pulse light source with reference to the trigger pulse. The camera described in the above supplementary note.

[Appendix 20]
The pulse control unit sets a set value that determines an interval between the trigger pulse and the exposure timing according to an arrival delay time until an infrared ray or a terahertz wave from the pulse light source reaches the camera, based on the trigger pulse. The camera according to the above supplementary note, which is set within a period excluding the arrival delay time.

[Appendix 21]
The camera according to the above supplementary note, wherein a bias voltage used for scanning of the imaging sensor is applied for a predetermined period after the elapse of a predetermined period from the exposure timing determined by the pulse control unit.

[Appendix 22]
The camera according to the above supplementary note, wherein the scanning position of the imaging sensor is set to an initial position in accordance with the exposure timing determined by the pulse control unit.

[Appendix 23]
An imaging system that includes a pulse light source, a camera, and a pulse controller.
Emitting infrared or terahertz waves from the pulse light source at a pulse interval received from the pulse controller,
An image captured by driving the image sensor with the camera is acquired at a pulse interval received from the pulse controller,
A first trigger pulse for determining the emission timing of the pulsed light source and a second trigger pulse for determining the imaging timing of the infrared and terahertz camera in the pulse control unit, respectively.
At this time,
Prior to the first trigger pulse, the second trigger pulse is generated with a set time interval, the first trigger pulse is output to the pulse light source, and the first trigger pulse is preceded. And outputting the second trigger pulse to the camera.

[Appendix 24]
The pulse control unit periodically generates the first trigger pulse and the second trigger pulse, and synchronizes the cycle of the first trigger pulse and the cycle of the second trigger pulse, respectively, The terahertz wave imaging method according to the above-described supplementary note, wherein the image is output to a pulse light source and the camera.

[Appendix 25]
The pulse control unit sets an interval between the first trigger pulse and the second trigger pulse to a set value when outputting the first trigger pulse or the second trigger pulse. A terahertz wave imaging method as set forth in the above supplementary note, which is characterized by the above.

[Appendix 26]
The pulse control unit is a set value that determines an interval between the first trigger pulse and the second trigger pulse based on a period from when the camera receives the second trigger pulse to when scanning is started. The terahertz wave imaging method according to the above supplementary note, characterized in that:

[Appendix 27]
The pulse control unit sets a set value for determining an interval between the first trigger pulse and the second trigger pulse as one preceding cycle excluding a light emission period of the pulsed light source based on the first trigger pulse. The terahertz wave imaging method according to the above supplementary note, wherein the terahertz wave is set within a range.

[Appendix 28]
The pulse control unit is configured to change an interval between the first trigger pulse and the second trigger pulse from one cycle of the first trigger pulse based on a light emission period of the pulse light source measured by the camera. The terahertz wave imaging method according to the above supplementary note, wherein the imaging method is set within a time period excluding the light emission period.

[Appendix 29]
The pulse control unit sets a setting value for determining an interval between the first trigger pulse and the second trigger pulse according to an arrival delay time until the infrared or terahertz wave from the pulse light source reaches the camera. The terahertz wave imaging method according to the above supplementary note, wherein the terahertz wave imaging method is set within a period excluding the arrival delay time with reference to the first trigger pulse.

[Appendix 30]
The above-described remarks, wherein the camera receives the second trigger pulse, and applies a bias voltage used for scanning of the imaging sensor for a predetermined period after a predetermined period has elapsed from the second trigger pulse. Imaging method for terahertz waves.

[Appendix 31]
The terahertz wave imaging method according to the above supplementary note, wherein the camera receives the second trigger pulse and sets the scanning position of the imaging sensor to an initial position at a timing according to the second trigger pulse.

[Appendix 32]
The terahertz wave imaging method according to the above supplementary note, wherein the camera starts scanning of the imaging sensor during a period from the transmission of the second trigger pulse to the transmission of the first trigger pulse.

[Appendix 33]
The control unit of the information processing device
A first trigger pulse that determines the light emission timing of a pulse light source that emits infrared or terahertz waves and a second trigger pulse that determines the imaging timing of the infrared and terahertz camera are preceded by the first trigger pulse. A pulse generator for generating two trigger pulses with a set time interval;
A program that operates as a pulse output unit that outputs each of the first trigger pulse and the second trigger pulse.

[Appendix 34]
The control unit as the pulse control unit periodically generates the first trigger pulse and the second trigger pulse, and synchronizes the cycle of the first trigger pulse and the cycle of the second trigger pulse. The program according to the above supplementary note, wherein the program is operated so as to output to the pulse light source and the camera, respectively.

[Appendix 35]
When the control unit is used as the pulse control unit to output the first trigger pulse or the second trigger pulse, an interval between the first trigger pulse and the second trigger pulse is set as a set value. The program according to the above supplementary note, which is operated so as to be set to

[Appendix 36]
The control unit is the pulse control unit, and the first trigger pulse and the second trigger pulse are calculated based on a period from when the camera receives the second trigger pulse to when scanning is started. The program according to the above supplementary note, wherein the program is operated so as to set a setting value that determines the interval.

[Appendix 37]
Using the control unit as the pulse control unit, a set value for determining an interval between the first trigger pulse and the second trigger pulse is excluded from a light emission period of the pulse light source based on the first trigger pulse. The program according to the above supplementary note, which is operated so as to be set within one preceding cycle.

[Appendix 38]
The control unit is the pulse control unit, and the interval between the first trigger pulse and the second trigger pulse is determined based on the light emission period of the pulse light source measured by the camera. The program according to the above supplementary note, wherein the program is operated so as to be set within a time obtained by removing the light emission period from one cycle of the pulse.

[Appendix 39]
The control unit is the pulse control unit, and the interval between the first trigger pulse and the second trigger pulse is set according to the arrival delay time until the infrared or terahertz wave from the pulse light source reaches the camera. The program according to the above-mentioned supplementary note, wherein the set value to be determined is operated so as to be set within a cycle excluding the arrival delay time with reference to the first trigger pulse.

[Appendix 40]
A recording medium on which the program is recorded.

[Appendix 41]
A recording medium in which a program for a computer including first, second input interfaces, first, second, third output interfaces, and a processor is recorded in a non-transitory manner in a computer-readable manner,
The program causes the processor to operate as follows:
Setting indicating a time interval between a first trigger pulse that determines the emission timing of a pulse light source that emits infrared or terahertz waves and a second trigger pulse that determines the imaging timing of the infrared and terahertz camera from the first input interface. A set value that defines a time interval for outputting the second trigger pulse preceding the first trigger pulse, the value being received by the processor;
The first trigger pulse and the second trigger pulse are sequentially generated as a first trigger pulse train and a second trigger pulse train by the processor with a time interval according to the set value,
The first trigger pulse train is sequentially output from the first output interface to the pulse light source by the processor, and the second trigger pulse train is directed to the infrared / terahertz camera. Sequentially output by the processor,
Further, a sensing image is received from the infrared / terahertz camera via the second input interface, and the sensing image is output to at least one of the third output interface / internal storage device / monitor,
Further, an adjustment mechanism for limiting the input range of the set value is operated by the processor as needed,
The adjustment mechanism restricts a set value input range to the set value satisfying at least one of the following conditions: i) a value larger than the driving time of the infrared and terahertz camera ii) a terahertz wave width based on the light source pulse signal Iii) A value within one cycle excluding the arrival delay time of the terahertz wave based on the light source pulse signal.

The present invention acquires a beam profile of a pulsed electromagnetic wave emitted from a pulsed light source, thereby facilitating the development, manufacturing and inspection of various pulsed light sources, and imaging by expanding the beam from a high-intensity pulsed light source. It can be used for non-destructive inspection.

This application claims priority based on Japanese Patent Application No. 2015-048497 filed on March 11, 2015, the entire disclosure of which is incorporated herein.

1, 2, 3, 4 Imaging system 10 Light source device (pulse light source)
11 Camera (Terahertz camera)
12 Pulse control unit (pulse control means)
13 Imaging Sensor 14 Computer (Pulse Control Unit)

Claims (16)

1. A pulsed light source that emits infrared or terahertz waves;
   A camera for imaging by driving an imaging sensor;
   A pulse control unit for generating a first trigger pulse for determining the light emission timing of the pulse light source and a second trigger pulse for determining the imaging timing of the camera;
   Have
   The imaging system, wherein the pulse control unit outputs the first trigger pulse to the pulse light source, and outputs the second trigger pulse to the camera prior to the first trigger pulse.
2. The pulse control unit periodically generates the first trigger pulse and the second trigger pulse, and synchronizes the cycle of the first trigger pulse and the cycle of the second trigger pulse, respectively, The imaging system according to claim 1, wherein the imaging system outputs the pulse light source to the camera.
3. The pulse control unit sets an interval between the first trigger pulse and the second trigger pulse to a set value when outputting the first trigger pulse or the second trigger pulse. The imaging system according to claim 1, wherein the imaging system is characterized.
4. The pulse control unit is a set value that determines an interval between the first trigger pulse and the second trigger pulse based on a period from when the camera receives the second trigger pulse to when scanning is started. The imaging system according to claim 3, wherein: is set.
5. The pulse control unit sets a set value for determining an interval between the first trigger pulse and the second trigger pulse as one preceding cycle excluding a light emission period of the pulsed light source based on the first trigger pulse. The imaging system according to claim 3, wherein the imaging system is set within a range.
6. The pulse control unit is configured to change an interval between the first trigger pulse and the second trigger pulse from one cycle of the first trigger pulse based on a light emission period of the pulse light source measured by the camera. 6. The imaging system according to claim 3, wherein the imaging system is set within a time excluding the light emission period.
7. The pulse control unit sets a setting value for determining an interval between the first trigger pulse and the second trigger pulse according to an arrival delay time until the infrared or terahertz wave from the pulse light source reaches the camera. The imaging system according to any one of claims 3 to 6, wherein the imaging system is set within a cycle excluding the arrival delay time with reference to the first trigger pulse.
8. 2. The camera according to claim 1, wherein the camera receives the second trigger pulse, and applies a bias voltage used for scanning of the imaging sensor for a predetermined period after a predetermined period has elapsed from the second trigger pulse. 8. The imaging system according to any one of items 7 to 7.
9. 9. The camera according to claim 1, wherein the camera receives the second trigger pulse and sets the scanning position of the imaging sensor to an initial position at a timing according to the second trigger pulse. The imaging system described in 1.
10. 10. The camera according to claim 1, wherein the camera starts scanning the imaging sensor during a period from the transmission of the second trigger pulse to the transmission of the first trigger pulse. Imaging system.
11. A pulse generator that generates a first trigger pulse that determines the light emission timing of a pulse light source that emits infrared rays or terahertz waves, and a second trigger pulse that determines the imaging timing of a camera that drives and images the imaging sensor;
    The pulse control device further comprising: an output unit that outputs the first trigger pulse to the pulse light source and outputs the second trigger pulse to the camera prior to the first trigger pulse.
12. The first trigger pulse and the second trigger pulse are periodically generated, and the period of the first trigger pulse and the period of the second trigger pulse are synchronized to each of the pulse light source and the camera. The pulse control device according to claim 11, wherein the pulse control device outputs the pulse control device.
13. The interval between the first trigger pulse and the second trigger pulse is defined as a period from when the camera receives the second trigger pulse until scanning is started, a light emission period of the pulse light source, and from the pulse light source. 13. The pulse control device according to claim 11, wherein the terahertz wave is set within one preceding period according to at least one of arrival delay times until the terahertz wave reaches the camera.
14. An imaging sensor for detecting infrared or terahertz waves;
    A pulse controller that generates a trigger pulse that determines the light emission timing of a pulse light source that emits infrared or terahertz waves;
    Including
    The said pulse control part outputs the said trigger pulse to the said pulse light source, determining the exposure timing of the said image sensor which preceded the time of setting value from the timing which outputs the said trigger pulse.
15. An imaging system that includes a pulse light source, a camera, and a pulse controller.
    Emitting infrared or terahertz waves from the pulse light source at a pulse interval received from the pulse controller,
    An image captured by driving the image sensor with the camera is acquired at a pulse interval received from the pulse controller,
    A first trigger pulse for determining the emission timing of the pulsed light source and a second trigger pulse for determining the imaging timing of the infrared and terahertz camera in the pulse control unit, respectively.
    At this time,
    Prior to the first trigger pulse, the second trigger pulse is generated with a set time interval, the first trigger pulse is output to the pulse light source, and the first trigger pulse is preceded. And outputting the second trigger pulse to the camera.
16. Computer processor,
    A first trigger pulse that determines the light emission timing of a pulse light source that emits infrared or terahertz waves and a second trigger pulse that determines the imaging timing of the infrared and terahertz camera are preceded by the first trigger pulse. A pulse generator for generating two trigger pulses with a set time interval;
    A recording medium that operates as a pulse output unit that outputs the first trigger pulse and the second trigger pulse, respectively.

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