JP2010216904A - Object detection method and lidar device, and environment measuring method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain detailed information of a geological formation including an object emitting weak fluorescence at the bottom of the sea by using an illuminating light emitted on the water or in the water. <P>SOLUTION: A lidar device 10 is suitable for taking the image of the fluorescence from an object 50 especially existing at the bottom of the sea. A first photomultiplier (light detection unit) 15 detects the scattering light returned from the object 50 and a second photomultiplier (light detection unit) 16 also detects the fluorescence returned from the object 50 with high sensitivity. In this lidar device 10, the depth of the object 50 is calculated only from the output of the first photomultiplier 15. The exposure timing of a camera 22 is set by a control unit 11 based on the second peak in the output of the second photomultiplier 16. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a laser radar (rider) device that obtains a fluorescent image emitted from an object by irradiating the object with laser light, or an object detection method using the same. The present invention also relates to an environment measurement method for measuring the environment using this object detection method.

  Conventional radar irradiates an object with radio waves and obtains information on the object from electromagnetic waves scattered and reflected from the object. A technique for performing similar measurement using laser light instead of radio waves is known as laser radar (LIDAR (Light Detection and Ranging)).

  Because laser light propagates in the air and underwater, the lidar technology is effectively used especially for ocean observation, etc., not only measuring the distance to the object, but also various information about the object. can get. For example, Patent Literature 1 describes a technique for obtaining an image by irradiating a pulsed laser beam from the air to the sea surface and controlling the timing at which reflected light, scattered light, and fluorescence are received by a microchannel plate. In this technique, reflected light from the sea surface, scattered light and fluorescence corresponding to the depth in the sea can be measured at the same time, so that the concentration of suspended matter and plankton in seawater can be measured.

  In particular, Patent Document 2 discloses a technique for irradiating laser light from a flying object and imaging weak fluorescence at that time. In this technique, a pulsed laser beam is irradiated as a diverging light to a region including an object on the sea, for example. In this case, although it is possible to irradiate a wide range, the amount of light applied to the object becomes small and the fluorescence becomes weak, so that imaging becomes difficult. On the other hand, the photomultiplier tube receives weak fluorescence emitted from the object, sets the optimum imaging timing from the output, and performs the imaging operation. Since the pulsed laser light arrives at the target object and the target object absorbs it, the fluorescence lasts only for a short time, so this configuration can be used to optimize the imaging timing. . Therefore, the image can be obtained with high sensitivity even for weak fluorescence.

JP-A-4-69546 JP 2003-83895 A

  However, when there are many elements that disturb the fluorescence emitted by the object, for example, when imaging the fluorescence emitted by the object on the seabed, it has been difficult to obtain a good image even using the above technique. .

  For example, a living moth (Kikumeishi) in the sea emits light with a wavelength of 508 nm, but its light intensity is very weak compared to irradiation light, reflected light, and scattered light. Therefore, before the fluorescence reaches the measuring instrument, the fluorescence itself is scattered and absorbed in the seawater, and the intensity is further attenuated.

Furthermore, not only is the distance to the object (、) long, but there are various disturbance factors on the sea surface and in the sea. For example, on the sea surface, this is caused by a decrease in transmitted light component due to a part of incident light being reflected. Waves also cause imaging distortion. In water, bubbles, water turbidity, and the like cause a decrease in transmitted light components. In particular, when this measurement is performed from a sailing ship, a large amount of bubbles generated in the water due to the ship's traveling wave is a problem. Reflected light and scattered light of sunlight on the sea surface, in the sea, and at the bottom of the sea serve as background light for the above-described measurement, and lowers the signal-noise ratio of weak fluorescence from the object generated by the irradiation light. Further, in actual measurement, not only the two-dimensional image of the fluorescence of the object but also the topography of the seabed where the object (珊瑚) is located, that is, water depth information is required.

  Therefore, it has been difficult to obtain detailed information on the topography including the object that emits weak fluorescence on the seabed by the rider device.

  The present invention has been made in view of such problems, and an object thereof is to provide an invention that solves the above problems.

In order to solve the above problems, the present invention has the following configurations.
In the object detection method according to claim 1 of the present invention, object detection is performed by irradiating illumination light toward an object in water from above the water, and detecting an image of light emitted from the object and the depth of the object. An irradiation step of irradiating the object with the first pulsed illumination light; a light receiving step of detecting light returned from the object side by a light detection unit and outputting a pulse; A depth calculating step for calculating the depth from the time difference between the second peak and the first peak in the pulse output, and setting the exposure timing of the image sensor based on the second peak in the pulse output. An exposure timing setting step, a re-irradiation step of irradiating the object with the second pulsed illumination light again, and light having substantially the same wavelength as the light emitted by the object at the exposure timing. Shoot Characterized by comprising an imaging step of a.
In the present invention, imaging of light emitted from an underwater object is performed using illumination light emitted from the water. At this time, a highly sensitive light detection unit is used separately from the image sensor. When the light detection unit detects light returned from the underwater object side by irradiation of illumination light, two peaks appear in the output pulse: a peak due to the water surface and a peak due to the object. The depth of the object is calculated from the time difference between the two peaks. In addition, the exposure timing is set based on the second peak, and when the illumination light is re-irradiated, imaging with the light emitted from the object is performed at this exposure timing.
In the object detection method of the present invention, in the light receiving step, a first light detection unit that receives light having substantially the same wavelength as the illumination light, and a wavelength substantially the same as light emitted by the object. And a second peak in the first pulse output from the first photodetector in the depth calculation step. The depth is calculated from the time difference between the two, and in the exposure timing setting step, the exposure timing is set based on the second peak in the second pulse output from the second photodetection unit. And
In the present invention, both the first light detection unit that detects scattered light and the second light detection unit that detects light (for example, fluorescence) emitted from the object are used as the light detection unit. The depth is calculated from the time difference between the two peaks in the output of the first photodetection unit, and the exposure timing is set based on the second peak in the output of the second photodetection unit. Imaging is performed with a high signal-to-noise ratio by reducing background light such as scattered light.

An object detection method according to claim 3 of the present invention is an object for irradiating illumination light from above the water toward an underwater object, and detecting an image of light emitted from the object and the depth of the object. An object detection method comprising: an irradiation step of irradiating the object with pulsed illumination light; a light receiving step of detecting light returned from the object side by a light detection unit and outputting a pulse; and the pulse A depth calculating step for calculating the depth from a time difference between the second peak and the first peak in the output; and light emitted from the object in synchronization with the second peak in the pulse output; An imaging step in which the imaging device starts imaging with light having substantially the same wavelength.
In this invention, the illumination light is irradiated from the water, but the re-irradiation step is not performed, and the depth calculation and the exposure start timing are set by the pulsed illumination light emitted in the irradiation step. This exposure start timing is set in synchronization with the second peak, and imaging of light emitted from the object by the pulsed illumination light emitted in the irradiation step is started at this exposure start timing. That is, depth calculation, exposure start timing setting, and imaging are performed by one irradiation of illumination light.

Moreover, the target object detection method which concerns on Claim 4 of this invention irradiates illumination light toward the target object in water from underwater, The target which detects the image of the light which this target object emits, and the depth of the said target object An object detection method comprising: an irradiation step of irradiating the object with the first pulsed illumination light; and a light receiving step of detecting light returned from the object side by a light detection unit and outputting a pulse. A depth calculating step for calculating the depth based on a peak in the pulse output; an exposure timing setting step for setting an exposure timing of an image sensor based on the peak in the pulse output; A re-irradiation step of irradiating the object again with illumination light; and an imaging step of imaging light having substantially the same wavelength as the light emitted by the object at the exposure timing with the image sensor. It is characterized in.
In the present invention, imaging of light emitted from an underwater object is performed using illumination light emitted from the water. At this time, a highly sensitive light detection unit is used separately from the image sensor. When the light detection unit detects light returned from the underwater object side by irradiation of illumination light, the depth is calculated based on the peak in the output pulse. In addition, the exposure timing is also set based on this peak, and when the illumination light is re-irradiated, imaging with the light emitted from the object is performed at this exposure timing.
In the object detection method of the present invention, in the light receiving step, a first light detection unit that receives light having substantially the same wavelength as the illumination light, and a wavelength substantially the same as light emitted by the object. And a second peak in the first pulse output from the first photodetector in the depth calculation step. The depth is calculated based on the time difference of the first and the exposure timing is set in accordance with the peak in the second pulse output from the second light detection unit in the exposure timing setting step. To do.
In the present invention, both the first light detection unit that detects scattered light and the second light detection unit that detects light (for example, fluorescence) emitted from the object are used as the light detection unit. The depth is calculated based on the time difference between the two peaks in the output of the first light detection unit, and the exposure timing is set in accordance with the peak in the second pulse output from the second light detection unit. Thus, imaging is performed.

Moreover, the target object detection method which concerns on Claim 6 of this invention irradiates illumination light toward the target object in water from the water, The target which detects the image of the light which this target object emits, and the depth of the said target object An object detection method comprising: an irradiation step of irradiating the object with pulsed illumination light; a light receiving step of detecting light returned from the object side by a light detection unit and outputting a pulse; and the pulse A depth calculating step for calculating the depth based on a time difference between the second peak and the first peak in the output; and substantially the same as the light emitted by the object in synchronization with the peak in the pulse output. And an imaging step in which the imaging device starts imaging with light having a wavelength.
In this invention, the illumination light is irradiated from underwater, but the re-irradiation step is not performed, and the depth calculation and the exposure start timing are set by the pulsed illumination light emitted in the irradiation step. The exposure start timing is set based on a peak in the output of the light detection unit, and imaging of light emitted from the object by the pulsed illumination light emitted in the irradiation step is started at the exposure start timing. That is, depth calculation, exposure start timing setting, and imaging are performed by one irradiation of illumination light.

In the object detection method of the present invention, the light detection unit receives light having substantially the same wavelength as the illumination light.
In the present invention, the light detection unit detects scattered light. Imaging is performed by calculating the depth based on the peak in the output and setting the exposure timing. That is, depth calculation, exposure timing setting, and imaging are performed using a single light detection unit that detects scattered light.
In the object detection method of the present invention, the light detection unit receives light having substantially the same wavelength as the light emitted by the object.
In this invention, the said light detection part detects the light (for example, fluorescence) which a target object emits. Imaging is performed by calculating the depth based on the peak in the output and setting the exposure timing. That is, depth calculation, exposure timing setting, and imaging are performed using a single light detection unit that detects light emitted from an object.
The object detection method of the present invention further includes a warning step for issuing a warning according to a value of a pulse output from the light detection unit after a predetermined time has elapsed from the irradiation step after the light receiving step. And
In this invention, particularly when performing imaging of light emitted from an underwater object using illumination light emitted from underwater, the influence of scattered light from bubbles in pulse output can be confirmed from the output after a predetermined time has elapsed. . By recognizing this, an alarm is issued.
In addition, the object detection method of the present invention includes a display step for displaying an image based on the image signal obtained by the imaging step.
In the present invention, the captured image is displayed in the display step.
In the object detection method of the present invention, the imaging step is performed corresponding to each of a plurality of wavelength regions, and a spectrum of light returning from the object side is calculated from an imaging result corresponding to the plurality of wavelength regions. It comprises a step.
In the present invention, imaging results at a plurality of wavelengths are obtained. Thus, in particular, the spectrum of light returning from the object is measured.
In the object detection method of the present invention, the light emitted from the object is fluorescence emitted from the object, and the illumination light is excitation light of the fluorescence.
In the present invention, a fluorescence image emitted from the object is obtained.
The object detection method of the present invention is characterized in that the illumination optical system of the illumination light and the incident optical system of the image sensor are controlled based on the depth calculated in the depth calculation step.
In the present invention, the imaging condition is controlled based on the calculated depth.

A rider apparatus according to claim 14 of the present invention is a rider apparatus that irradiates illumination light toward an object in water and detects an image of light emitted from the object and a depth of the object. An irradiation unit that oscillates the illumination light in a pulsed manner and irradiates the object; a light detection unit that detects light returning from the object side and outputs a pulse; and the pulse output based on the pulse output. A control unit that calculates the depth of the object from the water surface, and an imaging unit that obtains an image by exposing light having substantially the same wavelength as the light emitted from the object side based on the pulse output. It is characterized by doing.
In the rider apparatus according to the present invention, the irradiating unit emits illumination light to an object in water. Thereafter, the high-sensitivity light detection unit detects light returning from the object side. A control part calculates the depth of a target object based on the peak in the pulse output of this photon detection part. Moreover, since the timing at which fluorescence is detected in the imaging unit can also be recognized from the peak in this output, the imaging unit performs exposure to light having substantially the same wavelength as the light emitted from the object side at this timing. Thereby, imaging can be performed at this wavelength.
In the rider apparatus according to the present invention, the light detection unit may include a first light detection unit that receives light having substantially the same wavelength as the illumination light, and substantially the same wavelength as light emitted from the object. A second light detection unit that receives the light having the time difference between the second peak and the first peak in the first pulse output from the first light detection unit. The depth is calculated from the image, and the imaging unit performs exposure based on a second peak in the second pulse output from the second light detection unit.
In the present invention, the first light detection unit that detects scattered light and the second light detection unit that detects light (for example, fluorescence) emitted from the object are used as the light detection unit in the rider apparatus. . The depth is calculated from the time difference between the two peaks in the output of the first light detection unit, and the exposure timing is set based on the second peak in the output of the second light detection unit. Is done.
In the rider apparatus of the present invention, the irradiating unit oscillates a first pulsed illumination light after a predetermined interval and oscillates a second pulsed illumination light, and the imaging unit The exposure is performed after the oscillation of the second pulsed illumination light at an exposure timing set based on the pulse output obtained after the oscillation of the first pulsed illumination light.
In the present invention, the irradiation unit emits the second pulse-shaped illumination light after emitting the first pulse-shaped irradiation light. At this time, the exposure timing is set using the first pulse-shaped illumination light, and after the second pulse-shaped illumination light is emitted, imaging is performed using the exposure timing.

In addition, the rider apparatus according to the present invention includes a display unit that displays an image based on the image signal output from the imaging unit.
In the present invention, the captured image is displayed by the display unit.
The rider apparatus according to the present invention is configured to calculate a spectrum of light returning from the object side from an imaging result corresponding to the plurality of wavelengths, wherein a plurality of wavelengths are set as wavelengths of light emitted from the object. A processing unit is provided.
In the present invention, imaging results at a plurality of wavelengths are obtained. Thus, in particular, the spectrum of light returning from the object is measured.
In the lidar apparatus of the present invention, the plurality of wavelengths include water Raman scattering wavelengths.
In the present invention, light by water Raman scattering having a wavelength unique to water is measured as a reference.
In the rider apparatus according to the present invention, the illumination light exit port in the irradiation unit, the light entrance port in the first and second light detection units, and the light entrance port in the imaging unit have a water surface and a space. It is characterized by being provided.
In this invention, the head part which consists of an irradiation part, a light detection part, and an imaging part in a rider apparatus is provided on water, and the measurement with respect to the target in water is performed. For example, this corresponds to the case where the head portion of the rider device is disposed on the water in the hull.
In the lidar apparatus of the present invention, the illumination light exit port in the irradiation unit, the light entrance port in the first and second light detection units, and the light entrance port in the imaging unit are provided in water. It is characterized by that.
In this invention, a head part is provided in water and the measurement with respect to the object in water is performed. For example, this corresponds to the case where the head portion of the rider device is placed in water.

An environmental measurement method according to a twenty-second aspect of the present invention is characterized in that the object detection method is performed using the object as a bag to determine whether the bag is alive or dead.
In the present invention, the underwater environment is measured particularly by measuring the underwater dredging.
Moreover, the environment measurement method of the present invention is characterized in that the object detection method is performed from a plurality of moving bodies on the specific object.
In the present invention, the environment measurement is performed particularly from a plurality of moving bodies.
In the environment measurement method according to the present invention, the plurality of moving bodies include at least one of an artificial satellite, an aircraft, and a ship.
In the present invention, the environmental measurement is performed using an artificial satellite, an aircraft, a ship or the like.
In addition, the environmental measurement method of the present invention is characterized in that a base point is determined and the object is measured over time in a region including the base point.
In the present invention, the environmental change over time is measured.

Since the object detection method and the rider apparatus of the present invention are configured as described above, the details of the topography including the object that emits weak fluorescence on the sea floor using illumination light generated from the water or from the water. Information can be obtained with a high signal-to-noise ratio. In this case, in particular, when two light detection units corresponding to different wavelengths are used, it is possible to accurately calculate the depth and set the exposure timing. At this time, two light detection units corresponding to the different wavelengths. In particular, it is possible to accurately calculate the distance and set the exposure timing. At this time, even if there is a delay from when light enters the light detection unit until output is obtained, the influence on the distance calculation can be eliminated.
Alternatively, the same operation can be performed using a single light detection unit that detects substantially the same wavelength as the illumination light or the substantially same wavelength as the light emitted from the object. In this case, the same effect can be obtained with a simpler configuration.
Furthermore, when irradiating with illumination light, it is more appropriate if irradiation is performed twice in the irradiation step and re-irradiation step, the exposure timing is set using the irradiation step, and imaging is performed at this exposure timing after the re-irradiation step. Imaging can be performed.
Alternatively, the imaging result can be obtained more quickly by performing the imaging after the irradiation step without using the re-irradiation step. This method is particularly effective when the time from when the object absorbs illumination light until it emits fluorescence is long, when the time when it emits fluorescence is long, or when the water depth at the measurement point is known in advance. .
Also, especially when emitting illumination light from underwater, it is possible to inform the measurer whether the measurement environment is appropriate, such as the influence of bubbles in the water on the measurement using a warning step, so that more accurate measurement is possible. It can be carried out.
In addition, when illuminating light is emitted from the water to an underwater object, two peaks due to the water surface and the object appear in the output of the light detection unit. By analyzing these peaks, it is possible to appropriately calculate the depth and set the exposure timing. In addition, when emitting illumination light from underwater to underwater objects, scattered light or fluorescence is generated by bubbles or seawater directly under the head, so two peaks appear. Similarly, depth calculation and exposure Timing can be set. If these two peaks are not seen, a warning that the measurement is not being performed properly can be issued.

Further, by displaying the captured image, the user can see the image and further adjust the irradiation unit and the optical system of the image capturing unit more accurately, thereby enabling more precise measurement.
Further, by measuring the spectrum of light returning from the object, more detailed information about the object can be obtained.
In addition, by adopting a configuration in which fluorescence is detected as light returning from the object, the substance that emits fluorescence can be identified, and the object can be identified.
Further, if imaging is performed by feeding back the depth, a more appropriate image can be obtained, and imaging can be performed under optimum conditions.
Further, in the rider device of the present invention, if the head portion is provided on the water, for example, when the head portion is installed on the hull, the influence of the head portion on the movement of the hull and bubbles generated by the head portion are measured. The influence exerted can be reduced.
On the other hand, if the head portion is provided in water, the influence of the water surface or suspended matter existing on the water surface on the measurement can be reduced.

Further, according to the environment measuring method of the present invention, the environment of the seabed can be measured over a wide range to a narrow range.
At this time, if the cocoon is used as an object, the environment can be easily evaluated using the life and death of the cocoon as an index.
Further, if this measurement is performed from a plurality of moving bodies, a wide range of environmental measurements can be performed more precisely. In particular, if an artificial satellite, an aircraft, a ship, or the like is used as the moving body, a wide range and detailed environmental measurement can be performed. Furthermore, if this measurement is performed over time, it is possible to measure changes in the environment over time.

It is a figure which shows the structure of the rider apparatus used as embodiment of this invention. It is a figure which shows two types of forms which install the rider apparatus used as embodiment of this invention in a ship. It is a timing chart which shows operation | movement at the time of using the rider apparatus used as embodiment of this invention as a surface type | mold. It is a timing chart which shows operation | movement at the time of using the rider apparatus used as embodiment of this invention as a semi-submerged type. It is a figure which shows the emission spectrum of various soot.

  Hereinafter, a rider device as an embodiment for carrying out the present invention will be described. FIG. 1 is a diagram showing a configuration of the rider device 10. The rider device 10 is installed, for example, on a hull, and can image fluorescence from the seabed. In the rider apparatus 10, laser light that emits pulsed light is used as a light source, and the object is irradiated. Fluorescence emitted from the object is received by a photomultiplier tube and then imaged by an image sensor.

  In FIG. 1, the control unit 11 is a personal computer, for example, and has a function of controlling the entire rider apparatus 10. Therefore, all the constituent elements described below are connected to the control unit 11 and controlled.

  The laser power source 12 serves as a power source for causing the laser head 13 to emit light. Alternatively, it serves as a power source for cooling the laser head 13. In addition, although these are made into the different bodies in FIG. 1, it is good also as a structure with which these were integrated. The laser power supply unit 12 inputs a pulse voltage to the laser head 13 and oscillates the laser light by controlling it in a pulse shape.

  The laser head (irradiation unit) 13 emits laser light under the control of the control unit 11. For example, the emission wavelength is 355 nm, which is a solid-state laser excited by a flash lamp and driven by a Q switch. The laser head 13 is driven by a laser power source unit 12 and can emit a pulse-like high-intensity light corresponding to the pulse voltage, in particular, by a Q switch. The Therefore, although not shown, an emission optical system for controlling the spread and irradiation position of the irradiation light is installed at the light emission port of the laser head 13, and this emission optical system is also provided in the control unit 11. Connected. Thereby, a laser beam can be irradiated to the target object 50 on appropriate conditions.

  Here, the delay signal generator 14 controls the timing of the pulsed laser light emitted from the laser head 13 via the laser power supply unit 12 under the control of the control unit 11. Further, the light detection timing of the photomultiplier tubes 15 and 16 and the imaging (exposure) timing of the camera 22 are also controlled.

  The first photomultiplier tube (light detection unit) 15 can detect scattered light returned from the object 50 side with high sensitivity and high time resolution, and in particular, can detect weak light in photon units. . Since the first photomultiplier tube 15 detects the scattered light of the laser light, a filter that selectively transmits the wavelength of the laser light is installed on the incident side. That is, it is possible to detect light having substantially the same wavelength as laser light (irradiation light). Moreover, it is preferable that the photomultiplier tube has a gate function capable of controlling the light detection timing with a short time constant. The output of the photomultiplier tube 15 is output as a pulse having a pulse height corresponding to the detected number of photons through a preamplifier or the like. The first photomultiplier tube 15 detects scattered light incident thereon and outputs a single output. This output is input to the oscilloscope 17 and can be directly observed by the user. Further, it is also input to the control unit 11 and the delay signal generator 14. An incident optical system (not shown) is provided on the light incident side of the photomultiplier tube 15 so that scattered light from the object 50 side can be detected with high efficiency, and this light is detected with high efficiency. It is appropriately controlled so as to be able to.

  Similarly, the second photomultiplier tube (light detection unit) 16 detects light returned from the object 50 side with high sensitivity. In the second photomultiplier tube 16, a filter that selectively transmits the wavelength of the fluorescence is installed on the incident side in order to detect the fluorescence to be measured. That is, light having substantially the same wavelength as the light (fluorescence) emitted from the object 50 can be detected. The first photomultiplier is used to control the timing of light detection with a short time constant, to output through a preamplifier, etc., to be able to observe the output with an oscilloscope 17, and to provide an incident optical system. Similar to tube 15.

  The oscilloscope 17 is preferably an oscilloscope that can output two or more channels in order to observe the output pulses of two photomultiplier tubes.

  On the other hand, the light returned from the object 50 side is imaged by the imaging unit 20. The imaging unit 20 includes a camera 22, an optical filter 23, and an optical filter selector 24 via a detection optical system 21. Unlike the second photomultiplier tube 16, the imaging unit 20 detects light returning from the object 50 side as an image. Therefore, although the light detection sensitivity and time resolution of the imaging unit 20 are inferior to those of the second photomultiplier tube 16, it is possible to take an image.

  The detection optical system 21 can change the magnification of an image captured by the camera 22 by the control of the control unit 11 or the like, and includes a plurality of optical elements (lenses, mirrors, etc.). Thereby, the user can freely set the range captured by the camera 22. The incident optical system of the first photomultiplier tube 15, the incident optical system of the second photomultiplier tube 16, and the detection optical system 21 can be shared, and the light can be divided by a beam splitter as appropriate. . However, even in this case, the first photomultiplier tube 15 and the second photomultiplier tube 16 are configured to selectively detect light having a wavelength corresponding to scattered light and fluorescence, respectively.

  The camera 22 includes an imaging optical system and an image sensor inside thereof, obtains a two-dimensional image of incident light, and outputs an image signal corresponding thereto. The imaging optical system is composed of a plurality of optical elements (lenses, mirrors, etc.), and forms an image including the object 50 on the imaging element. The image sensor is preferably an ICCD (Image Integrated Charged Coupled Device), which is a kind of solid-state image sensor, and in particular, the exposure (electronic shutter) timing is controlled with a short time constant in the same manner as the first photomultiplier tube 15. Those having a gate function that can be used are preferable. This exposure operation starts in synchronization with the output from the photomultiplier tube 15. The ICCD has a configuration in which an image intensifier (image intensifier) is provided on the incident side of a CCD, which is a two-dimensional optical imaging element, and can capture a weak two-dimensional image. The output is made in the same manner as a CCD image sensor in ordinary visible light. Therefore, the image signal is input to the image display device (display unit) 18 so that the user can see the two-dimensional image.

  Further, an optical filter selector 24 is provided between the camera 22 and the detection optical system 21. The optical filter selector 24 is provided with a plurality of narrow-band optical filters, one of which is selected by the control from the control unit 11, and light transmitted therethrough enters the camera 22. It has become. Similar to the second photomultiplier tube 16, the transmission wavelength of the optical filter 23 corresponds to the fluorescence wavelength. That is, with this configuration, light having a fluorescence wavelength can be selected and detected by the camera 22.

  In FIG. 1, a laser head 13, photomultiplier tubes 15 and 16, and an imaging unit 20 are integrated as a head unit 30, for example, installed outside the hull of a ship, and laser light is emitted toward the object 50 side. It is configured to be able to detect the light that is irradiated and returned from the object 50 side. Other components are separated from the head part 30 and can be installed in the cabin of the ship.

  FIGS. 2A and 2B show a form when the rider device 10 is actually attached to a ship hull 60 and used. 2A shows a case where the entire head unit 30 of the rider apparatus 10 is located above the sea surface 70 (water type), and FIG. 2B shows that the light incident / exit port 31 in the head unit 30 is the sea surface (water surface). The case where it is under 70 (semi-immersion type) is shown. Here, the light incident / exit port 31 is a window set in common as a light exit port in the laser head 13, a light incident port in the first photomultiplier tube 15, and a light incident port in the imaging unit 20. In either case, the head part 30 is fixed to the hull 60. When the head unit 30 is a water surface type (a) provided through the sea surface and space, the influence of the sea surface 70 such as reflection or scattering of the laser light or the light returned from the object 50 on the sea surface 70 occurs. However, since the head portion 30 itself does not become a bubble generation source by wave generation, it is suitable for measurement performed while the hull 60 is traveling at high speed. On the other hand, in the case of the semi-submerged type (b), bubbles are generated due to the wave formation of the head portion 30 in the seawater as the hull 60 moves, and the influence of the sea surface 70 is removed. . Therefore, it is suitable for measurement when the hull 60 stops or runs at a low speed. That is, when the rider apparatus 10 (head unit 30) is installed on the hull 60 and used, the installation method on the hull can be appropriately selected according to the use mode.

  The rider apparatus 10 is particularly suitable for imaging fluorescence from an object 50 on the seabed. In observing the object 50 on the seabed, particularly important information is the depth of the seabed, which is the distance from the sea surface to the seabed (object 50). In this rider apparatus 10, the distance from the sea surface to the sea bottom can be calculated, and this distance information can be fed back to the fluorescence imaging operation.

  Hereinafter, the specific operation of the rider apparatus 10 will be described for each of the water type (FIG. 2A) and the semi-submerged type (FIG. 2B).

  First, the operation in the case of the water type (FIG. 2A) will be described. In this case, the light incident / exit port 31 is above the sea level. Although FIG. 2 (a) describes the case where the rider device 10 is installed on the hull 60 (ship), the same applies to the case where the rider device 10 is installed on a flying object such as an aircraft or helicopter. The target 50 on the sea floor is arbitrary as long as it is an object that emits fluorescence.

  FIG. 3 is a timing chart showing the operation when the waterborne rider apparatus 10 detects the fluorescence emitted from the object 50, that is, the operation of the object detection method executed in the rider apparatus 10, and the horizontal axis is It's time. In FIG. 3, (a) is the operation of the flash lamp used in the laser head 13, and (b) is the operation of the Q switch used in the laser head 13, both of which are pulse-driven, and the operation is controlled by the timing. The FIG. 4C shows the light emission operation of the laser head 13. FIG. 4D shows the scattered light scattered by the sea surface and the object upon receiving the laser light, FIG. 5E shows the output of the first photomultiplier tube 15 by the scattered light, and FIG. Fluorescence emitted from the sea surface and the object upon receiving light, (g) is this fluorescence upon arrival at the head unit 30, (h) is the output of the second photomultiplier tube 16 due to this fluorescence, (i) is The exposure timing in the camera 22 is set by the control unit 11 using the delay signal generator 14 based on the outputs of the first and second photomultiplier tubes 15 and 16. In FIG. 3, there is only one pulse in the operation of the Q switch in (b), but actually this pulse is repeatedly emitted at a constant period. That is, the laser light is oscillated in a pulse shape with a constant period. 3A to 3H are displayed corresponding to the first pulse (first pulse-shaped illumination light), but only the pulse oscillated next time is shown in FIG. It is displayed corresponding to (second pulsed illumination light).

  First, the laser power supply unit 12 turns on the flash lamp at the timing shown in FIG. However, the laser light is not emitted from the laser head 13 because the Q switch is off immediately after turning on.

Next, the laser power supply unit 12 turns on the Q switch at the timing shown in FIG. In order to obtain a sufficient light intensity, this timing is preferably set to about 1 μs from the rise of the flash lamp. As a result, a laser beam having a large intensity and a constant wavelength is emitted from the laser head 13, and the timing is T ₀ (T ₀ is a typical one) from the rise of the Q switch, as shown in FIG. Is delayed by about 100 ns). Thereby, pulsed laser light (first pulsed illumination light) is irradiated onto the object 50 (irradiation step).

The laser light first reaches the sea surface 70 and is scattered there. The arrival time from the light incident and exit port 31 to the sea surface and T _1. Thereafter, the laser light reaches the object 50 on the seabed. The arrival time from the sea surface 70 to the object 50 (the seabed) and _{T 2.} Therefore, the scattered light is generated as shown in FIG. 3D, reflecting the oscillation waveform and timing of the laser light.

Scattered light from the sea surface 70 is incident on the first photomultiplier tube 15 via the time T ₁ (the light incident and exit port 31), the through time scattered light T _{1 +} T ₂ from the object 50 1 Incident on the photomultiplier tube 15. However, since the detection delay time (T _DP ) generally exists in the output of the photomultiplier tube, the output of the first photomultiplier tube 15 is as shown in FIG. A peak appears (light reception step). Here, T _DP is typically about 10 ns, and its value is known in advance according to the characteristics of the photomultiplier tube. The first peak corresponds to the scattered light from the sea surface 70 and is detected after 2T ₁ + T _DP from the oscillation of the laser light, and the second peak corresponds to the scattered light from the object 50, and the oscillation of the laser light. From 2 × (T ₁ + T ₂ ) + T _DP .

Similarly, fluorescent light is emitted from the sea surface 70 by the laser beam that has arrived. This timing is the same as that of the above scattered light. Thereafter, fluorescence is emitted from the object 50 on the seabed. However, in general, fluorescence is emitted after a lapse of a certain time after absorbing the excitation light, and this time is defined as T _DL1 and T _DL2 for the sea surface 70 and the object 50, respectively. About _TDL2 , for example, when the target object 50 is a bag, it is about 10 ns. That is, the fluorescence emitted by these is emitted with a delay of T _DL1 and T _DL2 from the above scattered light, respectively. Further, the fluorescence from the object 50 (珊瑚) lasts for a certain period of time. Therefore, fluorescence is generated at the timing shown in FIG.

The fluorescence from the sea surface 70 and enters the second photomultiplier tube 16 via the time T _1, the fluorescence from the object 50 enters the second photomultiplier tube 16 via the time T _{1 +} T ₂ . That is, the fluorescence upon arrival at the second photomultiplier tube 16 is at the timing shown in FIG. On this occasion. Due to the influence of the optical system on the incident side of the second photomultiplier tube 16, the decay time constant of the fluorescence upon entering the second photomultiplier tube 16 is different between the one from the sea surface 70 and the one from the seabed. . As will be described below, in the rider apparatus 10, the camera 22 takes an image in accordance with this timing.

Accordingly, two peaks as shown in FIG. 3H appear at the output of the second photomultiplier tube 16 (light receiving step). However, as in the case of detection of scattered light (FIG. 3E), there is also a _TDP detection delay when the second photomultiplier tube 16 detects fluorescence. The first peak corresponds to the fluorescence from the sea surface 70 and is detected after 2T ₁ + T _DL1 + T _DP from the oscillation of the laser beam, and the second peak corresponds to the fluorescence from the object 50 and the oscillation of the laser beam. To 2 × (T ₁ + T ₂ ) + T _DL2 + T _DP .

Therefore, when the next pulse of laser light (second pulse-shaped illumination light) is emitted (re-irradiation step), as shown in FIG. 3 (i), the target in the output of FIG. 3 (h) If the exposure start timing of the camera 22 is set at a time earlier by _TDP than the time when the output of the object 50 by fluorescence is obtained, the imaging operation can be performed only for a short period in which the fluorescence is emitted ( Imaging step). That is, the exposure timing may be set by the control unit 11 based on the second peak in the output of the second photomultiplier tube 16 (FIG. 3G) (exposure timing setting step).

The exposure end timing can be appropriately set according to the shape of this peak, but can be set, for example, at a point earlier by _TDP than the timing at which the output becomes 1/2 of the peak value. . If the fluorescence time of the object 50 is known in advance, only the exposure start timing is controlled, and the exposure end timing can be set to be after the fixed fluorescence time has elapsed. In this case, for example, this time can be set to about 100 ns.

Further, even in the gate function in the ICCD, there is a delay time T _DC operation, this value is 55ns order of over Torigga example, are determined according to the characteristics of the ICCD. Therefore, the delay signal generator 14 and the like may be appropriately controlled so that actual exposure is performed at the timing shown in FIG.

At this time, since the transmission wavelength of the optical filter 23 is the fluorescence wavelength similarly to the second photomultiplier tube 16, the light having the fluorescence wavelength can be selected and detected by the camera 22. Thereby, even if this fluorescence is weak, the imaging can be performed with high efficiency.

The depth of the seabed is the distance between the sea surface 70 and the object 50, during which time a light arrival time becomes T _2. Therefore, a value obtained by multiplying the speed of light in water to be determined a T ₂ is the depth. As described above, the first peak in the output of the first photomultiplier tube 15 (FIG. 3 (e) is 2T ₁ + T _DP from the oscillation of the laser beam, and the second peak is 2 from the oscillation of the laser beam. Appears after x (T ₁ + T ₂ ) + T _DP Therefore, the time difference between these two peaks is 2 × T ₂ , from which T ₂ can be calculated, and the depth to the sea floor is obtained (depth calculation step) In this case, in the radar apparatus 10, the output actually obtained in this radar apparatus 10 is the output (e) of the first photomultiplier tube 15 and the output (h) of the second photomultiplier tube in FIG. In particular, since T ₂ , that is, the depth of the object 50 is calculated only from the output (e) of the first photomultiplier tube 15, for example, an accurate oscillation timing of the laser light (FIG. 3C). Even if it is unknown, it can be calculated Kill. In addition, it is possible to calculate this value regardless of the value of T _DP.

Since the time difference between the two peaks in the output (h) of the second photomultiplier tube 16 is 2 × T ₂ + T _DL2 −T _DL1 , when at least one of T _DL1 and T _DL2 is unknown it is difficult to calculate the T _2. However, if both of them are known accurately or have substantially the same value, T ₂ can also be calculated from the output (h) of the second photomultiplier tube 16. That is, in this case, the first photomultiplier tube 15 is not necessary, and only a single photomultiplier tube (second photomultiplier tube 16) may be used in the depth calculation step.

Further, the output (second peak) due to fluorescence from the object 50 at the output (g) of the second photomultiplier tube 16 and the object 50 at the output (e) of the first photomultiplier tube 15. The time difference from the output (second peak) due to the scattered light from is _TDL2 . Therefore, in particular, when performing control to make the exposure time constant, if the value of _TDL2 is known in advance, only the first photomultiplier tube 15 is used without using the second photomultiplier tube 16. It is also possible to control the exposure timing by using it. That is, as shown in FIG. _3G , the exposure start timing may be set _TDL2 - _TDP later than the time of the second peak in the first photomultiplier tube 15. At this time, the depth can be calculated from the output of the first photomultiplier tube 15 as in the case described above. Therefore, in this case, the second photomultiplier tube 16 is unnecessary.

In the above example, the first pulse-shaped illumination light is irradiated in the irradiation step, and the second pulse-shaped illumination light is set in the re-irradiation step, and the second pulse-shaped illumination light is used. The setting was made so that the generated fluorescence is imaged. However, when the time for which the target 50 emits fluorescence is sufficiently long, the re-irradiation step is not performed, and the fluorescence generated by the first pulsed illumination light can be imaged. In this case, in the exposure timing setting step, the time point when the second peak rise is confirmed may be set as the exposure start timing. That is, the image capturing unit 20 may start exposure in synchronization with this peak. The exposure end timing can be set when the second peak output falls below a certain value, or after a certain time from the exposure start timing. In this case, due to the presence of T _DP and T _DC, it starts imaging delayed from the actual start of the fluorescence. However, if the fluorescence time is sufficiently long, even in this case, imaging with respect to fluorescence can be sufficiently performed. At this time, this control can be performed using only the first photomultiplier tube 15 or only the second photomultiplier tube 16 as in the case of imaging in the re-irradiation step. In addition, when the water depth is known in advance, or at night when the background light is low and the exposure start timing and the exposure end timing of the imaging unit 20 have a sufficient margin, the first pulse-shaped exposure timing is used. It can also be set to image fluorescent light generated by illumination light.

Incidentally, from a comparison of FIG. 3 (e) (g) ( i), especially when _{T DL2} is greater than _{T DP} is than the peak of the second at the output of the first photomultiplier 15, a fluorescent since the arrival of late, it may be set exposure start timing after T _DL2 -T _DP than the rise of the second peak. Therefore, for example, when _TDL2 is long, the configuration using only the first photomultiplier tube 15 is particularly effective.

  In particular, when the above measurement is performed while moving the hull 60, the depth of the object 50 (the seabed) changes from moment to moment. In such a case, if the change in depth to the seabed is known, for example, it becomes easy to optimize the setting of the emission optical system of the laser head 13, the detection optical system 21 for the camera 22, and the like. Therefore, the control unit 11 can control these optical systems based on the depth obtained by the depth calculation step, and a good image can be obtained also in this respect.

  In the above operation, the light detection timing of the first and second photomultiplier tubes 15 and 16 is controlled by the delay signal generator 14, and the gate with the Q switch pulse in FIG. It is preferable that the light detection operation is started by the function.

  This output is input to the control unit 11 and the delay signal generator 14. The delay signal generator 14 turns on the electronic shutter of the image sensor of the camera 22 as shown in FIG. 3 (i) by using a gate function using the pulses of the output signals of the photomultiplier tubes 15 and 16 as a trigger. To start exposure. At this time, exposure is performed only for light in a specific wavelength region that has returned from the object 50 side and passed through the optical filter 23 (third step).

  Here, when there is no time dependency of the intensity of the background light at the fluorescence wavelength, the output of the second photomultiplier tube 16 is changed after the Q switch is turned on at the timing of FIG. When obtained in the form of FIG. 3 (h), the only light that causes this increase in output is fluorescence. Therefore, the camera 22 can take an image only during the time when the fluorescence is emitted. That is, in the rider apparatus 10, the camera 22 is controlled at an appropriate timing in order to obtain a fluorescent image.

  Then, if the image signal from the imaging unit 20 (camera 22) is output to the image display device 18, the user can visually confirm this image (display step). However, this step may be omitted, and various data processing may be performed after the image signal is stored in the storage medium, and then output to the image display device 18.

  Further, when two peaks are not seen in the output of the second photomultiplier tube 16 (FIG. 3 (h)), for example, when the object 50 (珊瑚) is not present on the seabed, This corresponds to a case where the illumination light does not reach the object 50 due to the existence or the seabed being too deep. Therefore, in this case, the control unit 11 can be configured to issue an alarm.

  On the other hand, FIG. 4 shows the operation when the semi-submerged rider apparatus 10 detects the fluorescence emitted by the object 50 as in FIG. 4A to 4C are the same as those in FIG. Here, since the light incident / exit port 31 is directly below the sea surface 70, it can be considered that the light incident / exit port 31 is at the same height as the sea surface 70. The feature in this case is that bubbles are generated in the sea (underwater) according to the movement of the hull 60 because the light incident / exit port 31 is under the sea surface. However, the influence of the sea level 70 as in the case of the floating type does not appear at all.

The emitted laser light (first pulsed illumination light) is scattered by air bubbles, seawater, etc. in a wide range in the depth direction, and the transmitted component is reduced. Thereafter, it reaches the object 50 (the seabed) and is scattered there. Accordingly, scattered light is generated at the timing shown in FIG. Again, the arrival time of the laser beam to the object 50 is T _2. In this case, unlike the case of FIG. 3, since the head part 30 is under the sea surface, the scattered light from the sea surface by illumination light does not generate | occur | produce. However, since scattered light is generated immediately below the head portion 30 due to bubbles, seawater, etc., in FIG. 4D, in addition to the scattered light from the object 50, the first peak generated immediately after irradiation. Exists. That is, two peaks are generated as in the case of FIG.

The first peak (scattered light due to bubbles, seawater, etc.) enters the first photomultiplier tube 15 (light entrance / exit 31) after a time corresponding to the depth, and the scattered light from the object 50 is through the time T ₂ is incident on the first photomultiplier 15 is detected after the delay time T _DP. Therefore, two peaks as shown in FIG. 4E appear at the output of the first photomultiplier tube 15 (light receiving step). The first broad peak corresponds to scattered light from bubbles of various depths, seawater, etc., and the first photomultiplier is already immediately after the oscillation of the first pulsed illumination light (after _TDP ). Recognized as the output of the tube 15. The second peak corresponds to the scattered light from the object 50 and is detected after 2 × T ₂ + T _DP from the oscillation of the laser light.

Here, as an index of the first peak, it is possible to monitor the output of the first photomultiplier tube 15 after a predetermined time has elapsed since the oscillation of the first pulsed illumination light. Here, the predetermined time can be _TDP from FIG. 4 (e). That is, when this value is large, many bubbles are generated and accurate measurement is difficult, so that the control unit 11 can issue an alarm in the image display device 18 (warning step). Alternatively, it may be set so that the imaging step is not performed while this value is large. Note that if the output of the first photomultiplier tube 15 can recognize the scattered light from the bubble as the first peak rather than the value immediately after the oscillation of the first pulsed illumination light, this peak value. May be monitored instead.

As in the case of FIG. 3, the object 50 on the seabed emits fluorescence after a delay time (T _DL2 ). Fluorescence (delay time _TDL1 ) is emitted from seawater even though it is weak. Therefore, fluorescence is generated at the timing shown in FIG.

These fluorescences enter the second photomultiplier tube 16 at the timing shown in FIG. That is, the fluorescence from the object 50 enters the second photomultiplier tube 16 via the time T _2. Here, as will be described below, as in the case of the waterborne type, the operation of taking an image of the camera 22 is performed in accordance with this timing.

A peak appears at the output of the second photomultiplier tube 16 as shown in FIG. 4 (h) (light receiving step). This second peak corresponds to the fluorescence from the object 50 and is detected after 2 × T ₂ + T _DL2 + T _DP from the oscillation of the laser beam. In addition, since the first peak appears immediately after the oscillation of the laser beam, it is easy to distinguish the first peak from the second peak.

Therefore, when the next laser light pulse (first pulse-shaped illumination light) is emitted (re-irradiation step), as shown in FIG. 4I, the exposure timing is set (exposure timing). Setting step), the imaging can be performed with high efficiency (imaging step). That is, the exposure start timing may be set by _TDP before the second peak in the output of the second photomultiplier tube 16 (FIG. 4 (h)). This is the same as in the case of FIG.

As above, the peak of the first one at the output of the first photomultiplier tube 15 (FIG. 4 (e)) appeared after T _DP from the oscillation of the laser beam, second peaks 2 from the oscillation of the laser beam XT ₂ + T Appears after _DP . Accordingly, the time difference between the first peak and the second peak is 2 × T ₂ as in the case of the water type (FIG. 3), and the second peak in the output of the first photomultiplier tube 15 is obtained. T ₂ can be calculated based on the time difference between the first peak and the first peak. Alternatively, since the second peak from the oscillation of the laser beam is detected after 2 × T ₂ + T _DP from the oscillation of the laser beam (FIG. 4C), the output of this laser beam and the second peak are detected. T ₂ can also be calculated from the time difference between. Therefore, T ₂ can be calculated based on the output of the first photomultiplier tube 15 by any of the above methods, and the depth to the seabed can be obtained. The control unit 11 can optimize the settings of the emission optical system of the laser head 13 and the detection optical system 21 for the camera 22 based on this depth, as in the case of the water type.

Since the second peak in the output (g) of the second photomultiplier tube 16 is 2 × T ₂ + T _DL2 + T _DP after the oscillation of the laser beam, T ₂ is calculated when T _DL2 is unknown. Difficult to do. If the T _DL2 is negligible compared to the 2 × T _2, or are known in advance exactly can also calculate the T ₂ from the output of the second photomultiplier tube 16 (g). That is, in this case, the first photomultiplier tube 15 is not necessary, and only a single photomultiplier tube (second photomultiplier tube 16) may be used in the depth calculation step.

Similarly to the case of the water type (FIG. 3), when the value of _TDL2 is known in advance and the control is performed to make the exposure time constant, the second photomultiplier 16 is not used. It is also possible to control the exposure timing using only the first photomultiplier tube 15. In this case, the exposure start timing may be set _TDL2 - _TDP later than the time of the second peak in the first photomultiplier tube 15. At this time, the second photomultiplier tube 16 is not necessary as in the case of the water type.

  In addition, if the time for which the object 50 emits fluorescence is sufficiently long, the re-irradiation step is not particularly provided, and it is possible to set to capture the fluorescence generated by the first pulsed illumination light. In this case, in the exposure timing setting step, the point in time when the rising of the second peak is confirmed can be set as the exposure start timing, as in the case of the water type.

  The point that the image signal can be output to the image display device 18 is the same as in the case of the water type (display step).

  Therefore, it is possible to obtain the fluorescence image emitted from the object 50 on the seabed and the depth to the seabed using the semi-immersive rider device 10.

  In the semi-immersed rider apparatus 10, in order to reduce the influence of air bubbles, the head unit 30 can be installed deeper than the sea surface for measurement. In this case, the depth in the above description is the distance from the head unit 30 to the object 50, and the accurate depth is the sum of this distance and the depth of the head unit 30. Since the depth of the head unit 30 can be recognized according to the installation state of the rider apparatus 10, an accurate depth can be calculated. That is, even in this case, an accurate depth can be calculated based on the above time difference.

  With the above operation, a weak fluorescent image from a target object in water can be easily obtained in both the water type and the semi-submerged type, and distance information to the target object can also be obtained. That is, three-dimensional information including an object in the sea (underwater) can be obtained. In addition, by obtaining the distance information to the object, it is possible to optimize the imaging conditions, so that a better image can be obtained.

  Further, a plurality of optical filters whose transmission wavelengths are changed every 2 nm, for example, are installed in the optical filter selector 24, the positional relationship between the rider device 10 and the object 50 is fixed, and the above measurement is performed for each optical filter. By doing so, the spectrum of the light returning from the object 50 can also be obtained. In this case, since data to be handled increases, an information processing unit including a storage unit (such as a hard disk) that stores an image signal in each imaging and an arithmetic processing unit (such as a CPU) that performs an operation between the image signals is configured in FIG. It is preferable to provide in addition to.

  At this time, for example, one of the optical filters can be adapted to the wavelength of the water Raman scattered light, and when these are incorporated in the optical filter selector 24, an image of the fluorescence from the object and its surroundings are present. Both water images can be obtained. At this time, the information processing unit appropriately synthesizes these two types of images so that a clearer image of the object can be obtained. Alternatively, when light having a wavelength of water Raman scattering cannot be confirmed, it is confirmed that the lidar apparatus 10 is out of order, does not face the water, or the illumination light does not reach the sea due to foreign matter in the sea surface or water. it can.

  In addition, for example, the user can see an image on the image display device 18 and confirm a target that the user wants to observe in particular. In this case, the user can control the emission optical system of the laser head 13 via the control unit 11 to narrow down the laser light to the object 50 and detect fluorescence emitted only from the object 50. it can.

  The lidar apparatus 10 is particularly suitable for obtaining a fluorescent image of an object on the seabed, but is suitable for imaging fluorescence emitted from a kite, for example. A cocoon (eg, Kikumeishi) containing green fluorescent protein (GFP) that emits light of a wavelength of 508 nm emits light of this wavelength. In particular, since only the living sharks produce this light emission, the distribution of the living sharks in the seabed can be measured by the measurement using the lidar device 10. FIG. 5 is a result of measuring emission spectra of various soot when excitation light having a wavelength of 365 nm is used. In FIG. 5, the excitation light itself is also detected at the same time. Many of them have a peak at 508 nm due to the GFP, but there are also those having peaks at other wavelengths. Therefore, the distribution of the soot containing a luminescent substance other than GFP can be similarly measured by using the optical filter 23 having a wavelength corresponding to the soot. Alternatively, as described above, the type of soot can also be determined by performing the above measurement at a plurality of wavelengths to obtain an emission spectrum. That is, by using the above-described rider device 10 or this object detection method, it is possible to perform environmental measurement that measures the distribution of quantities that serve as indices for evaluating the environment in the sea, such as the distribution of living sharks, over a wide range. In particular, it is also possible to measure changes in the environment over time by performing this measurement over time in the vicinity of a certain point (base point).

  Similarly, if there is a fluorescent material on the surface of another object on the seabed, such as a sunken ship or various wastes, it can be detected in the same manner. Even in this case, it is possible to measure the environment using the environmental indicators as these objects.

  In addition to a ship, the rider device 10 can be attached to various moving bodies to image weak fluorescence from a long distance. For example, an artificial satellite, an aircraft, or a human (diver) can be used as the moving body. At this time, if the measurement is performed by dividing the transmission wavelength of the optical filter into, for example, about 2 nm, a spectrum of light returning from the object can be obtained.

  Further, by attaching a plurality of rider apparatuses 10 to these moving bodies and performing measurement from different points and distances, environmental measurement can be performed under various measurement conditions. For example, when the target is a coral in the sea, analysis from a satellite with a wide field of view (10 km x 10 km or more), low resolution (2 to 3 m) and shallow water (water depth 0 to 5 m), narrow view from a ship Analysis of deep water area (about 5-30m) with medium resolution (about 10cm) (about 3m x 3m), high resolution (about 1cm) and shallow area (about 0-10m) in a very narrow area from divers Can be performed respectively. Therefore, it is possible to acquire a wide range of data if measurement is performed using these moving objects simultaneously in the same region.

  The rider apparatus and the object detection method described above can measure the distribution of various measurement objects as described above. Therefore, it can be used for the seafloor exploration and the like starting from the above environmental measurement. Moreover, it can also be used for exploration of objects in the atmosphere, not limited to the sea.

DESCRIPTION OF SYMBOLS 10 Rider apparatus 11 Control part 12 Laser power supply part 13 Laser head (irradiation part)
14 Delay Signal Generator 15 First Photomultiplier Tube (First Photodetector)
16 2nd photomultiplier tube (2nd photon detection part)
17 Oscilloscope 18 Image display device (display unit)
DESCRIPTION OF SYMBOLS 20 Image pick-up part 21 Detection optical system 22 Camera 23 Optical filter 24 Optical filter selector 30 Head part 31 Light entrance / exit port 50 Object 60 Hull 70 Sea surface (water surface)

Claims (25)

An object detection method for irradiating illumination light from above water toward an object in water, detecting an image of light emitted from the object and the depth of the object,
An irradiation step of irradiating the object with the first pulsed illumination light;
A light receiving step of detecting light returned from the object side by a light detection unit and outputting a pulse;
A depth calculating step for calculating the depth from a time difference between the second peak and the first peak in the pulse output;
An exposure timing setting step for setting an exposure timing of the image sensor based on a second peak in the pulse output;
A re-irradiation step of irradiating the object with the second pulsed illumination light again;
An imaging step of imaging light having substantially the same wavelength as the light emitted by the object at the exposure timing with the imaging element;
The object detection method characterized by comprising. In the light receiving step, a first light detection unit that receives light having substantially the same wavelength as the illumination light, and a second light detection unit that receives light having substantially the same wavelength as the light emitted from the object. And are used,
In the depth calculation step, the depth is calculated from a time difference between the second peak and the first peak in the first pulse output from the first light detection unit,
In the exposure timing setting step, the exposure timing is set based on a second peak in the second pulse output from the second light detection unit,
The object detection method according to claim 1. An object detection method for irradiating illumination light from above water toward an object in water, detecting an image of light emitted from the object and the depth of the object,
An irradiation step of irradiating the object with the pulsed illumination light;
A light receiving step of detecting light returned from the object side by a light detection unit and outputting a pulse;
A depth calculating step for calculating the depth from a time difference between the second peak and the first peak in the pulse output;
An imaging step in which the imaging device starts imaging in light having substantially the same wavelength as the light emitted by the object in synchronization with the second peak in the pulse output;
The object detection method characterized by comprising. An object detection method for irradiating illumination light from underwater toward an underwater object, detecting an image of light emitted from the object and a depth of the object,
An irradiation step of irradiating the object with the first pulsed illumination light;
A light detection unit that detects light returning from the object side and outputs a pulse; and a depth calculation step that calculates the depth based on a peak in the pulse output;
An exposure timing setting step of setting an exposure timing of the image sensor based on a peak in the pulse output;
A re-irradiation step of irradiating the object with the second pulsed illumination light again;
An imaging step of imaging light having substantially the same wavelength as the light emitted by the object at the exposure timing with the imaging element;
The object detection method characterized by comprising. In the light receiving step, a first light detection unit that receives light having substantially the same wavelength as the illumination light, and a second light detection unit that receives light having substantially the same wavelength as the light emitted from the object. And are used,
In the depth calculation step, the depth is calculated based on a time difference between the second peak and the first peak in the first pulse output from the first light detection unit,
In the exposure timing setting step, the exposure timing is set in conformity with a peak in the second pulse output from the second light detection unit,
The object detection method according to claim 4. An object detection method for irradiating illumination light from underwater toward an underwater object, detecting an image of light emitted from the object and a depth of the object,
An irradiation step of irradiating the object with the pulsed illumination light;
A light receiving step of detecting light returned from the object side by a light detection unit and outputting a pulse;
A depth calculating step for calculating the depth based on a time difference between the second peak and the first peak in the pulse output;
An imaging step in which an imaging device starts imaging in light having substantially the same wavelength as light emitted from the object in synchronization with a peak in the pulse output;
The object detection method characterized by comprising.   The object according to any one of claims 1, 3, 4, and 6, wherein the light detection unit receives light having substantially the same wavelength as the illumination light. Detection method.   The said light detection part receives the light which has a wavelength substantially the same as the light which the said target emits, The claim 1, The claim 4, The claim 1 characterized by the above-mentioned. Object detection method. After the light receiving step,
7. The apparatus according to claim 4, further comprising a warning step that issues a warning according to a value of a pulse output from the light detection unit after a predetermined time has elapsed from the irradiation step. The object detection method described.   The object detection method according to any one of claims 1 to 9, further comprising a display step of displaying an image based on the image signal obtained by the imaging step. The imaging step is performed corresponding to each of a plurality of wavelength regions,
11. The object detection according to claim 1, further comprising a step of calculating a spectrum of light returning from the object side from imaging results corresponding to the plurality of wavelength regions. Method.   The light according to any one of claims 1 to 11, wherein the light emitted from the object is fluorescence emitted from the object, and the illumination light is excitation light of the fluorescence. Object detection method.   13. The illumination optical system of the illumination light and the incident optical system of the image sensor are controlled based on the depth calculated in the depth calculating step. Item detection method according to item. A rider device that irradiates an object underwater with an illumination light and detects an image of light emitted from the object and a depth of the object,
An irradiation unit that oscillates the illumination light in a pulse shape and irradiates the object,
A light detection unit that detects light returning from the object side and outputs a pulse;
A controller that calculates the depth of the object from the water surface based on the pulse output;
Based on the pulse output, an imaging unit that obtains an image by exposing light having substantially the same wavelength as the light emitted from the object side;
A rider device comprising: The light detection unit includes a first light detection unit that receives light having substantially the same wavelength as the illumination light, and a second light that receives light having substantially the same wavelength as the light emitted by the object. And a detector
The control unit calculates the depth from a time difference between the second peak and the first peak in the first pulse output from the first light detection unit,
The imaging unit performs exposure based on a second peak in the second pulse output from the second light detection unit;
The rider apparatus according to claim 14, wherein The irradiation unit oscillates a second pulsed illumination light after a predetermined interval after oscillating the first pulsed illumination light,
The imaging unit performs exposure after oscillation of the second pulsed illumination light at an exposure timing set based on the pulse output obtained after oscillation of the first pulsed illumination light. The rider device according to claim 14 or 15, characterized by the above-mentioned.   The rider device according to any one of claims 14 to 16, further comprising a display unit that displays an image based on an image signal output from the imaging unit. A plurality of wavelengths are set as wavelengths of light emitted from the object,
The rider according to any one of claims 14 to 17, further comprising an information processing unit that calculates a spectrum of light returning from the object side from imaging results corresponding to the plurality of wavelengths. apparatus.   19. The rider apparatus according to claim 18, wherein the plurality of wavelengths includes a wavelength of water Raman scattering.   The illumination light exit port in the irradiation unit, the light entrance port in the first and second light detection units, and the light entrance port in the imaging unit are provided via a water surface and a space. The rider device according to any one of claims 14 to 19.   The light emission port in the irradiation unit, the light incident port in the first and second light detection units, and the light incident port in the imaging unit are provided in water. The rider device according to any one of claims 19 to 19.   An environment measurement method, wherein the object detection method according to any one of claims 1 to 13 is performed using the object as a bag to determine whether the bag is live or dead.   An environment measuring method comprising: performing the object detection method according to any one of claims 1 to 13 from a plurality of moving objects on the specific object.   The environment measurement method according to claim 23, wherein the plurality of moving objects include at least one of an artificial satellite, an aircraft, and a ship.   The environment measurement method according to any one of claims 22 to 24, wherein a base point is determined, and the measurement of the object is performed over time in a region including the base point.