JP2009008459A - Observation method of water grass - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new method for simply and quickly observing the growing state of water grasses with accuracy, without accompanying hazards or heavy labor in diving visual observation, or the like, due to a diver. <P>SOLUTION: In measuring the growing state of water grasses growing thick in water, at least an ultrasonic measuring method which is a remote-noninvasive measuring method and a laser excited emission detection method are combined and used. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a new method for observing aquatic plants in the ocean, rivers, lakes, and the like in order to accurately and accurately observe the existence and growth status of aquatic plants remotely and non-invasively.

  It is necessary to observe and evaluate the effects of warm wastewater from factories and power plants in coastal waters on the growth of aquatic plants simply and accurately, and to evaluate the effects of water quality changes in rivers and lakes. It is very important from the viewpoint of assessment, water use and disaster prevention in fisheries, food industry, industry and society.

  Conventionally, in these observation evaluations, when the water depth is more than a certain level, diving visual observation and tsubo hunting survey by divers have been mainly performed.

  However, these methods are problematic in that they are highly dangerous and involve excessive labor, and it is difficult to obtain an accuracy that enables objective comparison in a wide area.

  Therefore, the present invention solves the conventional problems from the background as described above, and easily observes the growth status of aquatic plants more accurately and without the danger and great labor of diving by divers. The challenge is to provide new ways to do this.

  The aquatic plant observation method of the present invention is characterized by the following in order to solve the above problems.

  First, when measuring the growth of aquatic plants growing in water, the growth of aquatic plants by using a combination of ultrasonic measurement and laser-excited emission detection, which is at least a remote and non-invasive measurement method The situation can be measured.

  Second: In the above method, the growth of aquatic plants was observed by the laser-excited luminescence detection method after grasping the topography of the bottom of the water, the topography of the bottom of sand and rocks, and the possibility of algae growth by ultrasonic measurement. To do.

  Third: When observing the topography of the bottom of the water, the topography of the bottom of sandy and rocky areas, the possibility of algae growth, etc., by ultrasonic measurement, the analysis of the primary and secondary reflections of the ultrasonic wave will produce aquatic plants at the bottom of the water. Analyzes the presence or absence of.

  Fourth: The presence of aquatic plants can be observed by irradiating laser light having a wavelength capable of exciting chlorophyll contained in aquatic plants and detecting light emission from the chlorophyll.

  Fifth: The position of irradiating laser light with a wavelength that can excite chlorophyll contained in aquatic plants, the emission point from chlorophyll, and the position of the photodetector for observing the emission from chlorophyll are the principles of triangulation Therefore, the distance between the emission point from the chlorophyll and the observation point can be calculated.

  Sixth: Laser light for exciting chlorophyll is scanned two-dimensionally and irradiated into water, and the in-plane distribution can be observed by observing light emission from the chlorophyll with a camera.

  Seventh: An optical filter that blocks the excitation light and allows the emission to pass through in order to reduce the influence of the excitation laser light scattered by the underwater plankton, bubbles, and other suspended matter and reflected by the observation camera Is used.

  Eighth: Exciting chlorophyll to select the optimal wavelength for photoexcitation of chlorophyll for aquatic plants with different types of chlorophyll as a means to discriminate the types of aquatic plants that grow in water For this purpose, a plurality of lasers having different oscillation wavelengths are used as light sources, and different emission wavelengths are detected by aquatic plants.

  Ninth: As means for measuring the growth status of aquatic plants growing in water, the laser having an oscillation wavelength of 470 nm or more, less than 540 nm, a laser having an optical output of 100 mW or more, and light emitted from the aquatic plants are efficiently collected. Lens optical system for guiding to the camera, camera for photoelectric conversion of the formed emission image, computer for image processing of electrical signals from the camera and data processing, peripheral devices for operation, and these Use an observation device with a housing to store the equipment and install it on or in the water.

  Tenth: When the ultrasonic measurement method and the laser excitation light emission detection method are used in combination, the data format is made common to enable easy data processing.

  As described above, the present invention is characterized in that at least the ultrasonic measurement method, which is a remote / non-invasive measurement method, and the laser excitation emission detection method are combined at least.

  Ultrasonic measurement methods and laser-excited luminescence detection methods are each known, but when combined with the observation of underwater aquatic plants, the remarkable effect has never been considered so far. .

According to the method of the present invention, of the ultrasonic method,
Underwater terrain information can be obtained accurately,
Wide dynamic range of measurement distance,
Being less susceptible to bubbles and suspended matter
The effect that the state of the bottom of the water is obtained from the multiple reflection information is obtained, and by the laser excitation emission detection method,
No false signals from objects other than aquatic plants,
It is possible to measure the distribution of aquatic plants in the depth direction,
The effect of being easily affected by bubbles and suspended matter is realized. And each of these methods has weak points, that is, the fact that there is an indeterminate element that is likely to cause an erroneous signal at the bottom of an inclined surface in the ultrasonic method, and the short-range dynamic range in the laser method is narrow. And weak points such as inability to obtain terrain information are relatively covered, and a synergistic remarkable effect is realized. For this reason, according to the present invention, it is possible to eliminate the conventional problems, and easily observe the growth status of aquatic plants more accurately without accompanying danger and great labor such as diving by divers. .

  Embodiments of the present invention will be described below. Of course, the invention is not limited by the following explanation.

  FIG. 1 shows the configuration of an ultrasonic bottom sediment analyzer (manufactured by Stenmar Micro Systems, model name: RoxAnn). It consists mainly of an ultrasonic transmission / reception unit (fish detector, frequency: 200 kHz) including a transducer, a data conversion unit, a DGPS (Differential Global Positioning System) for measuring position, and a data analysis unit (personal computer).

  As shown in FIG. 2, a primary reflected signal in which the ultrasonic wave transmitted from the transducer is reflected and received by the seabed, and a secondary reflected signal that is reflected by the sea surface and reflected and received by the seabed again. From the above, it is possible to estimate the quality of the seabed roughly.

  In this device, the “roughness” (particle size, etc.) of the material that constitutes the seabed from the primary reflection signal, and the secondary reflection signal to the “hardness” that accompanies differences in the quality and moisture content of the components. The system is configured to automatically analyze the particle size classification of the seabed sediment and the presence or absence of seaweed by taking in the relevant information and correlating the primary and secondary reflected signal intensities shown in FIG. The ocean bottom is scanned while navigating with an observation ship equipped with this device, and simultaneously the position data is captured by DGPS, and the analysis result of the ocean floor condition is displayed in real time on the map of the personal computer monitor. However, the division pattern shown in FIG. I-3 is provided as a standard value, and the relationship between the output values differs for each sea area with different seabed conditions. Therefore, in the measurement by this device, the relationship between the primary and secondary reflection intensities of the ultrasonic waves in the sea area to be used and the seabed situation is clarified in advance, and a classification pattern in the corresponding sea area is created.

Further, a GPS fish finder (manufactured by Plus Gain, model name: Fish Strike 1000C) was also used. This consists of an ultrasonic transmission / reception unit and a liquid crystal monitor unit, and transmits a sound wave (frequency: 200 kHz) to display an image of a reflection pattern from the seabed and water depth on a monitor. The feature of this apparatus is that image data of reflection patterns, water depth data, and GPS position data can be continuously recorded on a storage medium (about 78 hours on a 64 MB memory card). Therefore, in addition to being able to check the image of the reflection pattern at the site, you can perform operations such as color adjustment and sensitivity adjustment according to the reflection intensity of sound waves, image noise removal, etc. Various analysis images can be displayed again for the vicinity. In addition, since the water depth and position information are displayed together with the image of the reflection pattern, the measurement location can be easily determined. In addition, since it cannot output as numerical data in the measurement by this apparatus, it is difficult to perform analysis and drawing based on numerical values only by visual observation.
<Field experiment>
In order to examine the determination and distribution measurement of seaweeds by acoustic waves, field experiments using an ultrasonic bottom sediment analyzer, GPS fish finder and underwater camera were conducted in a predetermined sea area. The field experiment consists of stop observation and navigation observation. In the stop observation, the ship is fixed every 10m from the shore to the offshore 100m, and the underwater camera (presence / absence of seaweeds and species) is visually observed and recorded. Measurement of primary and secondary reflection intensity of ultrasonic waves by a sonic bottom sediment analyzer and a sound wave reflection image of a GPS fish finder were recorded. In the navigational observation, the mesh navigation was carried out around the Yusugi mound at a boat speed of about 5 knots, and the sound probe measurement using an ultrasonic bottom sediment analyzer and GPS fish finder was carried out in the form of a grid line. Note that the sound search data of the ultrasonic bottom sediment analyzer was taken every second.

  FIG. 4 shows the relationship between the primary and secondary reflection intensities of the ultrasonic bottom sediment analyzer at each stop. Since the directivity angle of the transducer of this apparatus is about 15 °, for example, the result at a depth of 5 m shows an average seabed condition in the range of about 1.3 m in diameter under the transducer.

  The primary reflection intensity is strong on the seabed with chrome or large stones with large leaves, and tends to be weak in sand or mud with small particle size, and the secondary reflection intensity is short with pebbles with hard stones exposed on the sea floor. It became clear that it was strong in a place like algae, and that the stones were covered with chrome leaves or tended to become weaker as the mud area had a high water content. Such a tendency can be said to be a result of well reflecting the method of analyzing the seabed condition from the primary and secondary reflection characteristics of the sound wave by this apparatus.

  The seabed condition classification pattern of the ultrasonic sediment analyzer was created (Fig. 5). By registering the pattern shown in FIG. 5 in the software of the data analysis unit of the present apparatus, the seabed situation is automatically analyzed based on this division pattern.

  FIG. 6 shows the seabed situation under the measurement line in different colors based on this seabed situation classification pattern. This is a hard copy of the screen of the data analysis unit (PC) of this device. If the classification of the corresponding sea area is registered in advance, the analysis result shown in the figure is displayed in real time on the map of the PC screen, and the seabed Measurement navigation is possible while checking the situation on the spot. In addition, drawing software is incorporated in the data analysis unit, and various drawing processes can be performed by taking in the numerical data of the apparatus as it is. FIG. 7 shows the result of plotting the measured lines shown in FIG. The distribution illustrated in the plane shown here is a result obtained by numerically supplementing the result obtained on the measurement line at intervals of 1 second. Accordingly, a more accurate distribution can be obtained by narrowing the measurement mesh interval and slowing the ship speed. FIGS. 8A and 8B show the results obtained by incorporating the water depth data into the results shown in FIGS. It can be seen that the mound is growing and chrome is growing on and near the mound, and the area around the mound is surrounded by pebbles, short algae and sand.

  The results of analyzing the results after 3 months in the same manner are shown in FIGS. Although the area around the mound was slightly widened, it was distributed over a wide area.Similarly, the rise of the mound, the chrome area on the mound and near the shore, and the mound area were surrounded by pebbles, short algae and sand areas It was recognized that

  On the other hand, the present inventors have developed a small laser radar for measuring the concentration distribution of phytoplankton (chlorophyll a) (FIG. 11), which is a bistatic laser using a CW laser (wavelength 532 nm). By adopting a special configuration called radar, it has become possible to construct a system that is extremely small, light, and consumes less power than a system that uses a conventional pulse laser.

  Therefore, we developed a device that measures the distribution of algae inhabiting the sea floor using a bistatic laser radar configuration. Although the basic configuration is the same, the assumed measurement distance is about 10 m and the fluorescence scattering of the algae is sufficiently strong. By using a normal CCD camera (previously using a cooled CCD), it is even smaller and lighter The two-dimensional distribution of algae can be measured by laser scanning or the like. In the sea area experiment, a laser and a measuring device are mounted on the seaweed observatory boat to measure seabed algae in the actual environment.

  As a result of conducting a fluorescence detection experiment using a sample (goldfish algae) simulating a seabed algae in a preliminary experiment in a pool as shown in FIG. 12, it has sufficient observation sensitivity up to a distance of about 10 m. It could be confirmed.

  In a preliminary experiment, goldfish algae (Cabomba caroliniana) was placed in a transparent container (5 × 5 × 20 cm) and placed in a pool as a target. To separate the fluorescence of chlorophyll a possessed by goldfish algae (peak at a wavelength of 685 nm) from the Raman scattered light of water and the scattered light of the laser, an optical filter R64 attached to the lens (wavelength transmitting through the long wavelength side and transmitting through 50%) 640 nm) and R66 were used.

  In this measurement method, the distance to the target is obtained by triangulation from the distance between the laser beam and the CCD camera (base line length) and the target angle obtained from the coordinates of the measurement image. In the preliminary experiment, the base line length is set to 25 cm, and the angle between the optical axis of the lens and the laser beam is set to 3.6 degrees, so that the center of the field of view of the CCD camera is captured at a point approximately 4 m from the camera. A range of approximately 2 to 15 m is imaged. FIG. 13 shows a fluorescent image captured by a CCD camera using an R64 filter. The light spot on the laser beam path is fluorescence from algae, and the line-shaped image is water Raman scattered light (appears in the vicinity of 655 nm when excited at a wavelength of 532 nm. It cannot be separated even by R67).

  In the preliminary experiment in the pool, the influence of external light is small and the measurement condition is ideal, but the fluorescence of the algae at a distance of 13 m is captured, and the distribution of the algae can be measured.

  A typical measured intensity distribution is as shown in FIG. 14, and Raman scattered light of water exponentially attenuates with distance, and captures the fluorescence of algae at the target position. It becomes almost 0 at a far distance. In the sea area experiment, fluorescence from phytoplankton on the laser beam is superimposed. By using this feature of intensity change, data processing such as separation of algae from phytoplankton and determination of distribution position can be simplified from the image. .

  Next, in order to measure the one-dimensional distribution of algae, an experiment was conducted in which the laser beam was scanned one-dimensionally with an optical scanner to measure the fluorescence from the algae. The experimental apparatus is almost the same as described above, but as shown in FIG. 15, (1) a mechanism capable of one-dimensional scanning of the laser beam with an arbitrary frequency and amplitude is added by an optical scanner, and (2) the laser beam The difference is that the distance (baseline length) between the CCD cameras is 50 cm, and (3) PC Micro Nikon 85mm F2.8D that can tilt the optical axis is used as the imaging lens. With regard to (3), since the conventional optical system images the laser beam from an oblique direction, the focal point is focused only at a certain distance, but it is possible to focus on a wider range by using a lens with a tilt mechanism. This makes it possible to prevent an effective decrease in sensitivity due to defocusing. Note that the vertical and horizontal positions of the CCD camera are different from those in the preliminary experiment, in which the laser beam direction (corresponding to the water depth direction) is the short side direction of the CCD, and the scanning direction of the laser beam is the long side direction of the CCD.

  In the preliminary experiment in the pool, the container was placed in a transparent container (5 × 5 × 20 cm), and the long axis of the transparent container was set at a point of 8 m in the laser beam scanning direction. Two types of algae (gold bomb algae (Cabomba caroliniana) and microsorium (Microsorium pteropus)) shown in FIG. 16 were used to see the difference in how to capture fluorescence between small and large leaves.

  The laser beam drives the optical scanner with a triangular wave, and its scanning width is about 40 cm at a point of 8 m. Since the laser irradiation time per unit time per unit area is shortened by laser scanning, the effective sensitivity is lowered. Therefore, the laser beam scanning method was studied for both low speed scanning and high speed scanning. When the laser beam is scanned over the long side of the CCD, the low-speed scan has a moving time of 1 pixel of CCD for 1/60 seconds or more (1 scan cycle 17 seconds or more), and the high-speed scan has a scan cycle of 60 ms or less. (Scanning frequency 60 Hz, multiple thereof is desirable). However, this is a case where the frame accumulation of the CCD camera is not used, and when accumulation is performed, the scanning time is multiplied by the accumulation count n.

  FIG. 17 shows the experimental results when the laser beam is scanned at a low speed. A part (one frame) of the scanning of the laser beam is displayed. Although the scanning cycle is 10 seconds, since the entire long side of the CCD camera is not scanned, the moving time for one CCD pixel is approximately 1/60 seconds. It can be seen that the entire measurement range is in focus, and that the use of a lens with a tilt mechanism has prevented defocusing.

  FIG. 18 shows the experimental results when the laser beam is scanned at high speed. By setting the scanning frequency to 120 Hz, the laser beam passes through the captured video image N times (photo left: 8 times, photo right: 16 times), and the fluorescence corresponding to that number is added. Even at the sample position of 8 m, the fluorescence intensity distribution is captured, and it can be seen that measurement was possible up to a distance of 8 m. Furthermore, it is possible to obtain a two-dimensional distribution of algae by towing the device. Moreover, since the two types of algae samples having different leaf sizes were sufficiently dense with respect to the diameter of the laser beam, almost the same fluorescence measurement results were obtained.

  When the device is towed, how the fluorescence intensity (algae) distribution is captured differs between low-speed scanning and high-speed scanning. In the low-speed scanning, a linear fluorescence intensity profile obtained by scanning the bottom of the sea with a laser beam as shown in FIG. 19 is obtained, and the presence or absence of algae on the bottom of the sea in the area indicated by the thick line is known. In the high-speed scanning, as shown in FIG. 20, the average value of the fluorescence intensity in the strip-shaped region is obtained, and the presence or absence of algae on the sea bottom in the region is known. In both cases of low speed scanning and high speed scanning, the shape of the region is different, but the resolution ability ΔD in the laser beam scanning direction and the resolution ΔV in the towing direction are expressed by the following equations. When Δd is the length in the laser scanning direction corresponding to one CCD pixel at a certain depth, the following is obtained.

ΔD = Δd
ΔV = towing speed V (m / s) × 0.033 (s) × frame accumulation count n (times)
Therefore, a towed body that can be towed with a measurement system and a measurement system for use in actual sea areas was manufactured (Fig. 21).

  The following was confirmed in the experiment in this sea area.

  That is, as shown in FIG. 22, it was possible to capture the distribution of algae at a depth of 1.5 to 6 m or even deeper.

  Therefore, from the above results, the ultrasonic measurement device and the laser-excited luminescence detection device are mounted on the observation ship, and the presence and growth of algae in the water are performed in the predetermined sea area from FIG. 1 to FIG. As a result of measurement, it was possible to easily grasp the algae growth status as more practical.

1 is a schematic diagram of an ultrasonic analyzer. The schematic diagram of the primary and secondary reflection of an ultrasonic wave. A classification (standard value) chart of the seafloor condition by ultrasonic analysis. Ultrasonic primary and secondary reflection intensity and seafloor situation diagram of measurement points. Plant division diagram. Ultrasonic analysis result (line) diagram. Ultrasonic analysis result (surface analysis) diagram. The resulting three-dimensional plotting process (a: line, b: area analysis). Analysis results (a: line, b: area analysis) after 3 months. 3D plotting process (a: line, b: area analysis) after 3 months. The underwater BIS laser radar conceptual diagram. Preliminary experiment (algae distribution measurement) device configuration diagram. The fluorescence imaging figure at the time of moving a target. Typical intensity distribution chart measured. FIG. The underwater plant photograph figure of experiment object. The fluorescence imaging figure in the case of a slow scan. The fluorescence imaging figure in the case of high-speed scanning. Schematic diagram in the case of low-speed scanning. Schematic diagram for high-speed scanning. Outline drawing of boat for sea area experiment. Schematic diagram of sea area test results.

Claims (10)

  When measuring the growth status of aquatic plants growing in water, the growth status of aquatic plants is measured by using at least a combination of ultrasonic measurement method and laser excitation emission detection method, which are remote and non-invasive measurement methods. A method for observing aquatic plants, characterized in that it is possible.   It is characterized by observing the growth of aquatic plants by laser-excited luminescence detection method after grasping the topography of the bottom of the water, the topography of the bottom of sand and rocks, and the possibility of algae growth by ultrasonic measurement. Item 4. The aquatic plant observation method according to Item 1.   When observing the topography of the bottom of the water, the topography of the bottom of sandy or rocky areas, the possibility of algae growth, etc. by ultrasonic measurement, the analysis of the components of the ultrasonic primary and secondary reflections shows the presence or absence of aquatic plants at the bottom of the water. The method for observing aquatic plants according to claim 1, wherein the state is analyzed.   The aquatic plant according to claim 1, wherein the presence of the aquatic plant can be observed by irradiating a laser beam having a wavelength capable of exciting the chlorophyll contained in the aquatic plant and detecting light emission from the chlorophyll. Similar observation method.   A position where the position of the laser beam with a wavelength that can excite chlorophyll contained in aquatic plants, the emission point from the chlorophyll, and the position of the photodetector for observing the emission from the chlorophyll are determined by the principle of triangulation The aquatic plant observation method according to claim 1, wherein the distance between the emission point from the chlorophyll and the observation point can be calculated.   The aquatic plant according to claim 1, wherein the in-plane distribution can be observed by two-dimensionally scanning laser light for exciting chlorophyll, irradiating it in water, and observing light emission from the chlorophyll with a camera. Similar observation method.   In order to reduce the influence of excitation laser light scattered by underwater plankton, bubbles, and other suspended substances and reflected by the observation camera, use an optical filter that can block the excitation light and transmit light. The aquatic plant observation method according to claim 1.   Light source to excite chlorophyll to select the optimal wavelength for photoexcitation of chlorophyll for aquatic plants with different types of chlorophyll as a means to discriminate the types of aquatic plants that grow in water The method for observing aquatic plants according to claim 1, wherein a plurality of lasers having different oscillation wavelengths are used to detect different emission wavelengths depending on the aquatic plants.   As a means of measuring the growth of aquatic plants growing in water, a laser having an oscillation wavelength of 470 nm or more and less than 540 nm, a laser having an optical output of 100 mW or more, and the light emitted from the aquatic plants is efficiently collected and guided to the camera. A lens optical system, a camera for photoelectrically converting the imaged emission image, a computer for image processing of electrical signals from the camera and data processing, peripheral devices for operation, and storage of these devices The aquatic plant observation method according to claim 1, wherein an observation apparatus including a housing for installation on or in water is used.   The aquatic plant according to claim 1, wherein the data format is made common in order to facilitate data processing when the ultrasonic measurement method and the laser excitation luminescence detection method are used in combination. Observation method.