JP2006162480A - Underwater detection system - Google Patents

Underwater detection system Download PDF

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Publication number
JP2006162480A
JP2006162480A JP2004355959A JP2004355959A JP2006162480A JP 2006162480 A JP2006162480 A JP 2006162480A JP 2004355959 A JP2004355959 A JP 2004355959A JP 2004355959 A JP2004355959 A JP 2004355959A JP 2006162480 A JP2006162480 A JP 2006162480A
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Prior art keywords
underwater
image
echo
dimensional
mode
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JP2004355959A
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Japanese (ja)
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Sanae Nagai
早苗 永井
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Furuno Electric Co Ltd
古野電気株式会社
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Priority to JP2004355959A priority Critical patent/JP2006162480A/en
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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S15/00Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems
    • G01S15/88Sonar systems specially adapted for specific applications
    • G01S15/96Sonar systems specially adapted for specific applications for locating fish
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/52Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S15/00
    • G01S7/56Display arrangements
    • G01S7/62Cathode-ray tube displays or other two-dimensional or three-dimensional displays
    • G01S7/6245Stereoscopic displays; Three-dimensional displays; Pseudo-three dimensional displays
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S15/00Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems
    • G01S15/88Sonar systems specially adapted for specific applications
    • G01S15/89Sonar systems specially adapted for specific applications for mapping or imaging
    • G01S15/8906Short-range imaging systems; Acoustic microscope systems using pulse-echo techniques
    • G01S15/8993Three dimensional imaging systems

Abstract

An underwater detection device capable of easily and accurately recognizing an underwater state three-dimensionally.
Three-dimensional echo display data is generated from echo data obtained by scanning in a horizontal mode and a vertical mode, and a three-dimensional fish school image 34 is displayed on a display screen 17a based on the echo display data. Display three-dimensionally. In addition to the school of fish images 34, three-dimensional images such as an umbrella beam scan region 32 in the horizontal mode, a fan beam scan region 33 in the vertical mode, a seafloor topographic image 35, and an iso-depth line 36 are stereoscopically displayed. indicate.
[Selection] Figure 3

Description

  The present invention relates to an underwater detection device such as a scanning sonar used to detect a wide range of underwater.

  Scanning sonar is a type of underwater detection device that transmits an ultrasonic beam over a wide range in water, receives echoes by scanning in a predetermined direction, and displays an image of a school of fish based on the received echoes. In general, scanning sonar uses a horizontal mode in which an umbrella-shaped ultrasonic beam is transmitted into the water at a predetermined tilt angle and echoes are received by scanning across all horizontal directions, and a fan-shaped area on a vertical plane in a predetermined horizontal direction. And a vertical mode for transmitting a sound beam and receiving an echo by scanning the sector area. The scanning sonar is described in, for example, Patent Documents 1 to 3 listed below.

  FIG. 16 is a diagram for explaining the principle of the scanning sonar. In the figure, 50 is a scanning sonar mounted on a ship 51, 52 is a transmitter / receiver provided in the scanning sonar 50, 53 and 54 are ultrasonic beams emitted from the transmitter / receiver 52, and 55 is a water surface. In the horizontal mode, an umbrella-shaped ultrasonic beam 53 is simultaneously transmitted from the transducer 52 toward all directions in the water at a predetermined tilt angle (a depression angle) δ. Then, after transmitting the beam, the transducer 52 is scanned in the circumferential direction to form a reception beam that scans spirally at high speed in the direction of arrow C, and receives the echo reflected from the school of fish and the bottom of the water. In the vertical mode, the ultrasonic beam 54 is transmitted from the transmitter / receiver 52 to a sector-shaped vertical section as shown by the hatched lines in the figure. Then, after transmitting the beam, the transducer 52 is scanned in the vertical direction to form a reception beam that scans the fan-shaped area in the direction of arrow D, and the echo reflected from the school of fish and the bottom of the water is received. On the display screen of the scanning sonar 50, the images of the fish school and the bottom of the water are displayed in color according to the signal strength of the echo received by such a scan.

  FIG. 17 shows an example of an image displayed on the display screen of the scanning sonar 50. Reference numeral 60 denotes a display screen. On this screen 60, a horizontal mode video H obtained from echoes received in the horizontal mode and a vertical mode video V obtained from echoes received in the vertical mode are displayed side by side. In the horizontal mode image H, 61 is a hull mark, 62a and 62b are fish images obtained from echoes, and 63 is a water bottom image obtained from echoes. The vertical mode video V is composed of two videos V1 and V2. V1 is an image obtained by vertical scanning in the direction V1 in the horizontal mode image H, 64a is an image of a school of fish obtained from the echo, and 65a is an image of the bottom of the water obtained from the echo. V2 is an image obtained by vertical scanning in the direction V2 in the horizontal mode image H, 64b is an image of a school of fish obtained from the echo, and 65b is an image of the bottom of the water obtained from the echo. The fish school images 64a and 64b in the vertical mode image V correspond to the fish school images 62a and 62b in the horizontal mode image H, respectively.

JP 2003-202370 A JP 57-196172 A JP-A-9-43350

  In the conventional scanning sonar, as shown in FIG. 17, an image of a school of fish obtained from echo data is displayed by two-dimensional drawing. However, in such a two-dimensional display, if a three-dimensional image of a school of fish and its location in water is to be considered, the horizontal mode video H and the vertical mode video V must be combined in the head. Experience is required to do exactly. Therefore, it is difficult for an inexperienced user to easily image a three-dimensional image.

  On the other hand, the above-mentioned Patent Document 3 describes an ultrasonic sonar that can recognize the spread and thickness of a school of fish three-dimensionally. In this document, volume data in which echoes received from the sea are stored in three-dimensional Cartesian coordinates is created, and this volume data is subjected to isosurface processing using echo level threshold values. Each isosurface is made semi-transparent with a light / dark density difference or a hue difference and displayed in an overlapping manner.

  However, although the thing of the said patent document 3 can grasp | ascertain a three-dimensional fish school, it expresses the thickness of the perpendicular direction by giving a difference in a density and a color to the picture of the fish school displayed on a plane. In such a display, it is difficult to intuitively recognize the state of the school of fish. Moreover, it is impossible to comprehensively and accurately grasp the underwater situation only by displaying the fish school.

  In view of the above-described problems, an object of the present invention is to provide an underwater detection device that can easily and accurately recognize an underwater state three-dimensionally.

  In the present invention, an image of underwater information in a scan area is transmitted based on an echo received from a transmitter by transmitting an ultrasonic signal in the form of an umbrella beam to a wide range in water and scanning the wide range in a predetermined direction. 3D echo display data is generated from the echo data obtained by scanning, and the underwater information in the scan area is displayed on the display screen as a 3D image based on the echo display data. It is trying to display.

  In this way, by displaying underwater information obtained by scanning a wide range of underwater as a three-dimensional image, even inexperienced persons can easily recognize underwater information such as fish school three-dimensionally. At the same time, the position of the school of fish in the scan area can be seen at a glance, and the entire underwater situation can be accurately grasped.

  In an exemplary embodiment of the present invention, an ultrasonic signal is transmitted from a transmitter in the form of an umbrella beam to a wide range in the water, and the wide range is scanned in a predetermined direction. 3D echo display data is generated from the echo data obtained by scanning, and the underwater information in the scan area is transmitted based on the echo display data. It is displayed on the display screen as a virtual 3D image similar to an umbrella beam with a vessel at the apex. According to this, the underwater information is displayed as a conical stereoscopic image.

  The present invention includes a first mode in which an ultrasonic signal is transmitted underwater and an echo is received by scanning in a first direction, and a second mode in which an echo is received by scanning in a second direction. In addition, the present invention can be applied to an underwater detection device that displays an image of underwater information in the scan area based on the received echo. In this case, three-dimensional echo display data is generated from the echo data obtained by the scan in the first mode and the echo data obtained by the scan in the second mode, respectively. A three-dimensional image of underwater information based on the echo display data and a three-dimensional image of underwater information based on the echo display data in the second mode are displayed on the display screen in a three-dimensional manner. According to this, since the underwater information in different scan areas is superimposed and displayed in a three-dimensional manner, it is possible to recognize images of a school of fish and the like from various angles and to grasp the underwater information more accurately.

  In a typical embodiment, the first mode is a horizontal mode that receives echoes by scanning across all horizontal orientations, and the second mode scans a sector of the vertical plane at a predetermined horizontal orientation. This is a vertical mode in which echo is received. However, the present invention is not limited to this, and as one of a plurality of modes, for example, a slant mode in which scanning is performed by transmitting an ultrasonic beam to a semicircular inclined surface region obliquely downward from the water surface. Etc. are also conceivable.

  In the present invention, in an underwater detection device that transmits an ultrasonic signal underwater and displays an image of underwater information in a scan area based on an echo received by scanning in a predetermined direction, echo data obtained by scanning 3D echo display data can be generated from this, and this echo display data can be stored for the number of scans, and a 3D video of the school of fish in the scan area can be displayed as a history based on the stored echo display data. According to this, since multiple sections of the school of fish are displayed at the same time as the number of histories, the shape and scale of the school of fish can be easily grasped, and the movement status and location of the school of fish can be easily grasped. it can.

  In a preferred embodiment of the present invention, the 3D image of the scan area is displayed on the display screen so as to overlap the 3D image of the underwater information. According to this, since the detection area by scanning can be clearly recognized in three dimensions, the underwater information can be grasped more accurately.

  In a preferred embodiment of the present invention, threshold setting means for setting a threshold value for the signal level of the echo is provided, and a three-dimensional image of the school of fish is displayed as a history only for echoes having a signal level equal to or higher than the set threshold value. To do. According to this, since the fish image displayed in the history is clear from the image due to noise, the state of the fish school can be more easily grasped.

  In a preferred embodiment of the present invention, transparency setting means for setting the transparency of a stereoscopically displayed image is provided. According to this, the higher the transparency, the clearer the image of the overlapping portion is displayed, and it becomes easier to recognize a three-dimensional image such as a school of fish or a scan area. Also, if the transparency is lowered, the video behind the overlap can be hidden.

  In a preferred embodiment of the present invention, the viewpoint of a stereoscopically displayed video can be arbitrarily changed. According to this, it is possible to grasp the volume of the school of fish more accurately by viewing the same image from various angles.

  In a preferred embodiment of the present invention, a 3D image of the water bottom topography is displayed together with a 3D image of underwater information. According to this, since the water bottom topography is displayed as a stereoscopic image, the state of the water bottom, the position of the school of fish, etc. can be recognized in three dimensions, and the underwater state can be grasped more accurately.

  According to the present invention, even an inexperienced user can easily and accurately grasp the underwater situation in a three-dimensional manner using a stereoscopic image.

  FIG. 1 is a block diagram of a scanning sonar 100 according to the present invention. In the figure, reference numeral 10 denotes a transmitter / receiver, which at the time of transmission converts a transmission signal acoustically and transmits an ultrasonic beam into the water, and at the time of reception receives an echo reflected by a target in water and converts it into an electrical signal. To do. As the transducer 10, for example, a cylindrical or spherical transducer is used. The transmitter in the present invention may perform both transmission and reception like the transmitter / receiver 10, or may perform only transmission. In the latter case, a receiver is provided separately from the transmitter. Reference numeral 11 denotes a scanning unit, a transmission circuit that generates a transmission signal to be given to the transducer 10, a reception circuit that amplifies an echo received by the transducer 10 and extracts a signal of a predetermined frequency component by a filter, and a transmission operation. It comprises a transmission / reception switching unit that switches between reception operations, a beam forming unit that forms a reception beam for receiving echoes by horizontal and vertical scanning, and the like.

  An operation unit 12 includes keys, dials, and the like for setting and adjusting various parameters such as a tilt angle and a horizontal azimuth angle, and constitutes a threshold setting unit and a transparency setting unit in the present invention. Reference numeral 13 denotes a control unit that controls the operation of the scanning sonar 100, and reference numeral 14 denotes an image processing unit that generates an underwater image such as a school of fish based on a received echo signal. Here, the control unit 13 and the image processing unit 14 are configured as a one-chip microprocessor (CPU) 15, but the control unit 13 and the image processing unit 14 may be provided independently. Reference numeral 16 denotes a VRAM (Video RAM) in which data of the underwater video generated by the image processing unit 14 is stored, and reference numeral 17 denotes a display unit that displays the underwater video in color based on the data in the VRAM 16. The display unit 17 includes a CRT, a liquid crystal display, or the like.

  Reference numeral 18 denotes a memory composed of ROM, RAM, and the like, and 19 is a seabed map database. In addition to the tilt angle θ and the horizontal azimuth angle φ, the memory 18 is provided with an area in which parameters such as a history threshold Z, history count N, and transparency α, which will be described later, are set. Although not shown, an area for temporarily storing received echo data, three-dimensional drawing data, and the like is secured. The submarine map database 19 stores the three-dimensional display data of the seabed topography at each point in correspondence with the latitude and longitude, and a commercially available electronic chart (for example, published by the Geographical Survey Institute) can be used. A GPS (Global Positioning System) receiver 20 for acquiring the earth coordinates is mounted on the ship as a unit different from the scanning sonar 100.

  FIG. 2 is a diagram showing a state of scanning in the horizontal mode (hereinafter referred to as “horizontal scan”) and scanning in the vertical mode (hereinafter referred to as “vertical scan”) in the scanning sonar 100. During horizontal scanning, an umbrella-shaped ultrasonic beam 21 is transmitted in all horizontal directions at a predetermined tilt angle θ, and then a reception beam 22 is formed by scanning in the direction of arrow A to receive an echo. In the vertical scan, the ultrasonic beam 23 is transmitted to a sector area of approximately 90 ° on a vertical plane at a predetermined horizontal azimuth angle φ, and then a reception beam 24 is formed by scanning in the direction of arrow B to generate an echo. Receive. The horizontal scan and the vertical scan may be performed alternately or concurrently. Reference numeral 25 denotes a ship carrying the scanning sonar 100, 26 denotes an underwater fish school, and 27 denotes the seabed.

  FIG. 3 is a diagram illustrating an example of an underwater image displayed on the display unit 17. Reference numeral 17 a denotes a display screen of the display unit 17. The display screen 17a includes a ship 31, a scanning region 32 of an umbrella-shaped ultrasonic beam (hereinafter referred to as “umbrella beam”) in the horizontal mode, and a fan-shaped ultrasonic beam (hereinafter referred to as “fan beam”) in the vertical mode. ) Scan area 33, fish school image 34, and seafloor topographic image 35 are three-dimensionally displayed as a three-dimensional image. The scanning area 32 of the umbrella beam is displayed as an image of a cone (solid cone), but the actual scanning area 32 is the surface of the cone formed by the receiving beam (strictly speaking, the receiving beam is Since it has a constant thickness, the scan region 32 includes the surface of the cone and its vicinity). 36 is an iso-depth line on the surface of the cone, 37 is an intersection line between the scanning area 32 of the umbrella beam and the scanning area 33 of the fan beam, and 38 is an intersecting surface of the scanning area 33 of the cone and the fan beam. is there. Reference numeral 39 denotes a data display column for displaying the current position (latitude and longitude) of the ship 31 acquired from the GPS receiver 20 and the water depth value at the position. The water depth is measured by a sounding device mounted on a ship or a scanning sonar 100 having a sounding function. The display of the water depth value may be omitted.

  The umbrella beam scan area 32 and the fan beam scan area 33 are displayed based on data such as the tilt angle θ and the horizontal azimuth angle φ set by the operation unit 12. The fish image 34 is displayed on the intersection line 37 of the scan areas 32 and 33 based on the echo data obtained by the horizontal scan and the three-dimensional echo display data generated from the echo data obtained by the vertical scan. Is displayed. The seafloor topographic image 35 is displayed based on the seafloor topographic data at the current position acquired from the seafloor map database 19. The iso-depth line 36 is obtained by calculation from the data range, the tilt angle θ, etc., and is displayed.

  In FIG. 3, the underwater information in the scan region 32 is displayed on the display screen 17a as a virtual solid (cone) image similar to an umbrella beam having a transducer (not shown) mounted on the ship 31 as a vertex. Is displayed. In addition to the fish school image 34, the underwater information image includes an underwater floating object and an image reflected by the seabed, but these are not shown in FIG. 3 for simplification. In FIG. 3, three-dimensional images of the ship 31, the umbrella-shaped beam scanning region 32, the fan-shaped beam scanning region 33, the fish image 34, the seabed topographic image 35, and the iso-depth line 36 are displayed on the same display screen 17a. It is displayed three-dimensionally overlaid. Therefore, as viewed from the ship 31, it is possible to grasp at a glance which volume of school of fish exists in which direction and at what depth by the three-dimensional image. In particular, since the underwater information in the different scan areas 32 and 33 is superimposed and displayed in a three-dimensional manner, the fish school image 34 can be recognized in a multifaceted manner, and the underwater information can be grasped more accurately. Further, since the scan areas 32 and 33 are displayed in 3D, the detection area can be clearly recognized in 3D. Furthermore, since the seabed topographic image 35 is displayed as a three-dimensional image, the state of the seabed and the position of the school of fish can be recognized in three dimensions, and the underwater state can be accurately grasped. Even when the above-described echo image of the seabed is displayed, the three-dimensional seafloor topographic image 35 overlaps the echo image, so that the bottom of the sea can be easily understood and a fish with a bottom such as a flounder can be easily identified.

  In this case, the transparency of the video may be set by the operation unit 12. Transparency here is a factor that expresses how sharply the image of the overlapped portion looks when the images overlap, and the higher the transparency, the clearer the image of the overlapped portion is displayed. The lower the is, the more difficult it is to see the image of the overlapped portion. For example, when the transparency in FIG. 3 is high, the seabed topography (not shown in FIG. 3) in the back of the scanning area 32 of the umbrella beam is clearly displayed, and the scanning area 32 of the umbrella beam and the fan beam are displayed. The fish school image 34, the iso-depth line 36, etc. in the overlapping part with the scan area 33 also appear clearly. This makes it easier to recognize a three-dimensional image such as a scan area, a school of fish, or seabed topography. In addition, when it is desired to hide the video behind the overlapping portion and emphasize only the video in front, the transparency may be set low.

  FIG. 3 shows a display example when a stereoscopically displayed underwater image is viewed from a certain direction, but the viewpoint for viewing the underwater image may be arbitrarily changed. FIG. 4 is a display example in that case, and shows a stereoscopic image when the ship 31 in FIG. 3 is viewed from the right direction. The variable operation of the viewpoint is performed in the operation unit 12. For example, by setting or switching the direction of the viewpoint, an underwater video viewed from an arbitrary viewpoint can be displayed. This makes it possible to more accurately grasp the volume of the school of fish and the state in water.

  FIG. 5 is a principle diagram for explaining a history display mode according to another embodiment of the present invention. FIG. 5A shows a case in which history display is performed by changing the tilt angle with a fixed azimuth angle. One vertical mode video V1 and two horizontal mode videos H1 and H2 are superimposed to form a three-dimensional image. It is an example displayed on the screen. Since H1 and H2 of the horizontal mode video have a time difference, this is a history. FIG. 5B shows a case where the tilt angle is fixed and the history display is performed by changing the azimuth angle, and one horizontal mode video H1 and two vertical mode videos V1 and V2 are overlapped. It is an example of displaying in three dimensions. Since V1 and V2 of the vertical mode video have a time difference, this is a history. 5 (c) and 5 (d) are examples in which history display is performed using a plurality of videos in only one mode. In FIG. 5 (c), history display is performed using two horizontal mode videos H1 and H2. In FIG. 5D, the history is displayed by two vertical mode videos V1 and V2. The history display mode is set by operating the operation unit 12 (FIG. 1).

  According to such a history display, it is possible to grasp the shape of the fish school in three dimensions by simultaneously displaying multiple sections of the fish school as many as the number of histories, so that the skeleton of one fish school can be known and the size of the fish school can be easily estimated. Can do. For example, as shown in FIG. 6, for a relatively large school of fish 26, the tilt angles are sequentially changed to θ1, θ2, and θ3 based on the principle of FIG. 5A, and scanning is performed at each tilt angle. When this is done, the echo data obtained from the school of fish 26 is stored in the memory 18 for the number of scans. The number of scans at this time is the number of histories. As a result, the three-dimensional fish image 34 shown in FIG. 7 is displayed in three dimensions based on the echo history data stored in the memory 18, and the shape of the fish school and the size of the school of fish are relatively large. Can grasp. In FIG. 7, since the horizontal mode video and the vertical mode video are displayed in an overlapping manner as shown in FIG. 5A, the fish school can be recognized from various angles, thereby further improving the shape and scale of the fish school. It becomes possible to grasp accurately.

  In FIG. 5, the images of H1 and H2 and the images of V1 and V2 are obtained by scanning at different times, but they are scanned at different frequencies using the method of Patent Document 1 described above. By doing so, H1 and H2 videos and V1 and V2 videos can be obtained simultaneously. In addition to the example shown in FIG. 5, a history display can be performed by simultaneously displaying a plurality of horizontal mode images H1 and H2 and a plurality of vertical mode images V1 and V2. Furthermore, in the case of a ship that is sailing, history display can be performed by utilizing the fact that the scan area changes as the ship advances.

  Moreover, when the history display mode is used, in addition to the three-dimensional grasp of the fish school shape described above, for example, the movement status of the fish school can be grasped. That is, as shown in FIG. 8, when the tilt angle is sequentially changed to θ1, θ2, and θ3 and scanning is performed at each tilt angle, echo data obtained from the fish school 26 moving in the X direction is obtained. Are stored in the memory 18 for the number of scans. The number of scans at this time is the number of histories. As a result, based on the echo history data stored in the memory 18, three-dimensional fish school images 34a, 34b, and 34c as shown in FIG. On the other hand, when the fish school 26 has not moved and stays in the same place, even in the history display mode, the fish school image displayed on the display screen 17a does not change as shown in FIG. A dimensional fish school image 34 is obtained.

  In FIG. 9, the fish school images 34 a, 34 b and 34 c are displayed three-dimensionally on the same display screen 17 a together with the ship 31, the seabed topographic image 35 and the scan areas 32 and 33. The direction in which the school of fish is moving can be clearly understood from the three-dimensional image.

  Also in the history display mode, as in the previous example, the transparency of the video may be set by the operation unit 12, or the viewpoint for viewing the video may be arbitrarily changed. In addition, if a threshold is set for the signal level of the received echo and history display is performed only for echoes having a signal level equal to or higher than the set threshold, the image due to noise can be removed to leave a clear history. it can. The threshold at this time is hereinafter referred to as “history threshold”. Setting of the history threshold value is performed in the operation unit 12.

  Further, the operation unit 12 can switch the history display between the detailed mode and the simple mode. In the detailed mode, for example, a stereoscopic image as shown in FIG. 9 is displayed on the screen, and in the simple mode, for example, as shown in FIG. Such a simplified history display may be displayed. In FIG. 10, the display of the fan beam scan area 33, the seabed topographic image 35, and the like in FIG. 9 is omitted.

  FIG. 11 is a flowchart showing a procedure for displaying an underwater video. This procedure is executed by the control unit 13 of the microprocessor (CPU) 15. Hereinafter, a procedure for displaying an image will be described with reference to FIG. First, the history threshold Z, the history count N, and the transparency α are set in the operation unit 12 (steps S1 to S3). As described above, the history threshold value Z is a threshold value for discriminating the echo signal level of the school image displayed in history. The history count N is the number of times the fish school video is left as a history (for example, the history count is N = 3 in FIG. 9). As described above, the transparency α is a factor indicating how clear the overlapping images are. Each set value is stored in a predetermined area of the memory 18 shown in FIG.

  Next, horizontal scanning or vertical scanning is performed by the scanning unit 11, and echo data for one scan is acquired (step S4). In the case of a horizontal scan, the data for one scan is the echo data (signal level) received while the reception beam 22 makes one rotation (360 °) in the A direction in FIG. In the case of the vertical scan, the data for one scan is the data (signal level) of the echo signal received while the reception beam 24 is rotated approximately 90 ° in the B direction in FIG. The echo data thus obtained by one scan is temporarily stored in a predetermined area of the memory 18.

  Next, the scan count and the history count N are compared (step S5). As a result of comparison, if the number of scans does not exceed the history number N (step S5: NO), the process proceeds to step S7, and if the number of scans exceeds the history number N (step S5: YES), the process proceeds to step S6. Since the number of scans is 1 for the first time, the determination in step S5 is NO, and the process proceeds to step S7 without executing step S6.

In step S7, polygon (polygonal surface) data is acquired based on the echo data obtained in step S4. Here, a triangular polygon P as shown in FIG. 12 is targeted. 12, reference numeral 22 denotes a reception beam in horizontal scanning, SP 1 , SP 2 , SP 3 ,... Represent sampling points of the reception beam 22, and an arrow A represents a scanning direction. The triangular polygon P is a unit triangle formed by connecting three sampling points. In FIG. 12, only some triangular polygons P are shown. The echo signal level is measured at each sampling point, and the data is stored in the memory 18. Therefore, each triangular polygon P has signal level data at the three sampling points that are the vertices. In addition, each piece of data obtained at each sampling point has three-dimensional data (earth coordinates) consisting of an X coordinate value and a Y coordinate value determined from latitude and longitude, and a Z coordinate value determined from a tilt angle. In FIG. 12, the triangular polygon P formed by the horizontal scan is shown, but the principle is the same for the triangular polygon formed by the vertical scan. In step S7, the signal levels of echoes at three vertices are read out from the memory 18 for each triangular polygon P formed in one scan.

  Next, it is determined whether or not the signal levels of the three points of the acquired triangular polygon P are all equal to or higher than a threshold value (step S8). This threshold is the history threshold Z set in advance in step S1. Since the signal level of the echo increases at the place where the fish school is present, the ratio of the triangular polygons P whose three signal levels are all equal to or higher than the threshold increases. As a result of the determination, if at least one of the three signal levels of the triangular polygon P is less than the threshold (step S8: NO), the triangular polygon P is ignored and the process returns to step S7, and the next triangular polygon P Judgment is made. On the other hand, if the signal levels of the three points of the triangular polygon P are all equal to or higher than the threshold value (step S8: YES), the three-dimensional data (earth coordinates) of each vertex of the triangular polygon P is stored in the memory 18 (step S9). . This three-dimensional data constitutes the three-dimensional echo display data in the present invention. Thereafter, it is determined whether or not the processing has been completed for all the triangular polygons P (step S10). If the processing has not been completed (step S10: NO), the process returns to step S7, and the next triangular polygon P is processed. Steps S8 and S9 described above are performed.

  If it is determined in step S10 that the processing has been completed for all the triangular polygons P (step S10: YES), the process proceeds to step S11 to draw a seabed map. In step S <b> 11, information on the current position (latitude and longitude) is acquired from the GPS receiver 20, and data on the seabed topography corresponding to the current position is extracted from the seabed map database 19. Then, based on the extracted data, the seafloor topographic image 35 as shown in FIG. 3 is stereoscopically displayed on the display screen 17 a of the display unit 17.

  Next, a fish school video is drawn using the three-dimensional data of the triangular polygon stored in step S9 (step S12). Since the triangular polygons used at this time all have a signal level of three or more threshold values and correspond to a school of fish, the 3D image obtained from the aggregate of the triangular polygons is the same as the 3D image of the school of fish. Represents. As a result of the processing in step S12, the fish image 34 as shown in FIG. 3 is displayed three-dimensionally on the display screen 17a of the display unit 17. Subsequently, a ship, a scan area, an iso-depth line, and the like are drawn (step S13). As a result of the processing in step S13, the ship 31, the umbrella beam scan area 32, the fan beam scan area 33, the isodepth line 36, and the like as shown in FIG. 3 are three-dimensionally displayed on the display screen 17a. . At this time, the data value is also displayed in the data display field 39. Note that the order of steps S11 to S13 described above may be changed.

  Next, it is determined whether or not drawing is to be ended (step S14). If a drawing end operation is performed on the operation unit 12 (step S14: YES), the processing is ended. If the drawing end operation is not performed (step S14: NO), the process returns to step S4 to acquire data for the next one scan. In step S4, if the previous scan was a horizontal scan, the current scan is a vertical scan. Then, steps S5 to S14 are executed based on the echo data obtained by the vertical scan. When returning from step S14 to step S4 again, this time a horizontal scan is performed, and steps S5 to S14 are executed based on the echo data obtained by the horizontal scan. Thereafter, similarly, horizontal scanning and vertical scanning are alternately performed. However, it is not essential for the present invention to perform horizontal and vertical scanning alternately, and horizontal scanning and vertical scanning may be performed simultaneously in parallel.

  By saving the echo data acquired for each scan in the memory 18, the saved data can be read and the fish school video can be displayed as a history as shown in FIGS. If the number of scans exceeds the history count N in step S5 while repeating the scan several times (step S5: YES), the oldest data stored in the memory 18 is erased (step S6). Update the data history. As a result, the latest fish school video is always displayed on the display screen 17a of FIGS.

  In FIG. 3, the image of the scanning area 32 of the umbrella beam in the horizontal mode, the image of the scanning area 33 of the fan beam in the vertical mode, and the fish image 34 in both scanning areas are displayed. The image of the scan area in any one of the above and the fish school image in the area may be displayed. FIG. 13 shows an example thereof, in which the image of the scan area 32 in the horizontal mode and the fish school image 34 in the scan area 32 are stereoscopically displayed. Along with these, each image of the ship 31, the seafloor topographic image 35, and the iso-depth line 36 is also stereoscopically displayed. The image of FIG. 13 corresponds to the image of FIG. 3 excluding the vertical mode scan region 33 and the fish school image in the region, and the fish image 34 is near the surface of the cone forming the horizontal mode scan region 32. 3D image of a school of fish in

  In the above embodiment, the scanning sonar having both the horizontal mode and the vertical mode has been described as an example. However, the present invention may be applied to a scanning sonar having only one of the modes. it can. For example, in the case of a scanning sonar having only the horizontal mode, the image as shown in FIG. 13 is displayed. Further, the present invention can also be applied to a scanning sonar having three or more modes (for example, a horizontal mode, a vertical mode, and a slant mode described later). In addition, the present invention is not limited to scanning sonar, but can also be applied to underwater detection devices such as PPI sonar and fish finder.

  Various embodiments of the present invention other than the above can be considered. For example, in the above-described embodiment, the horizontal mode and the vertical mode are exemplified as the scan mode. However, the present invention can also be applied when scanning is performed in the slant mode and the vertical mode. FIG. 14 is a conceptual diagram of the slant mode, and in this mode, an ultrasonic beam is transmitted from the water surface 41 to the region of the semicircular inclined surface 42 directed obliquely downward, and scanning is performed over the region. 43 represents a ship, and 44 represents a school of fish.

  In addition, the three-dimensional display mode (3D mode) and the two-dimensional display mode (2D mode) can be switched in the operation unit 12, and when the three-dimensional display mode is set, FIG. 3, FIG. 4, FIG. When a stereoscopic image such as 9 is displayed and the two-dimensional display mode is set, a planar image as shown in FIG. 17 may be displayed.

  In the above-described embodiment, the seafloor map database 19 is used to display the seafloor topographical image 35. However, the seabed map database 19 is not used, and processing is performed on the echo data obtained by the scan, so that the seafloor The terrain may be displayed in three dimensions.

  In the above-described embodiment, the threshold is set for the echo signal level in the case of the history display shown in FIGS. 7 and 9, but the threshold is also set in the case of the normal display shown in FIGS. You may do it.

  The present invention can also be applied to an automatic tracking type sonar that performs automatic tracking by changing the tilt angle according to the movement of a school of fish. In this case, by adopting the history display of the present invention, even if the school of fish moves irregularly, the history of fish school images can be accurately displayed by the automatic tracking function. A scanning sonar having such an automatic tracking function is described in, for example, Japanese Patent Application Laid-Open No. 2003-315453.

  Further, by applying the history display in the present invention, as shown in FIG. 15, it is also possible to display the movement history 34a to 34c of the fish school together with the movement history 31a to 31c of the ship. Reference numerals 32a to 32c denote movement histories of umbrella beams, and reference numerals 36a to 36c denote movement histories of iso-depth lines. In FIG. 15, the fan beam scan area and the seafloor topographic image are not displayed, but these may be displayed.

It is a block diagram of the scanning sonar which concerns on this invention. It is the figure which showed the mode of the horizontal scan and the vertical scan. It is the figure which showed the example of the underwater image | video displayed on a display part. It is the figure which showed the underwater image | video at the time of changing a viewpoint. It is a principle figure explaining history display mode. It is a figure explaining the change of the tilt angle in history display mode. It is the figure which showed the example of a display of the underwater image in log | history display mode. It is a figure explaining the change of the tilt angle in history display mode. It is the figure which showed the other example of a display of the underwater image in log | history display mode. It is an example of a simplified history display. It is the flowchart which showed the procedure in the case of displaying an underwater image | video. It is a figure explaining a polygon. It is the figure which showed the other example of the underwater image | video displayed on a display part. It is a conceptual diagram of slant mode. It is an application example of a history display. It is a figure explaining the principle of a scanning sonar. It is an example of the image | video displayed on the display screen of the scanning sonar.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Transceiver 11 Scan part 12 Operation part 13 Control part 14 Image processing part 17 Display part 17a Display screen 18 Memory 19 Submarine map database 21 Ultrasonic beam 23 Ultrasonic beam 25 Ship 26 Fish school 27 Submarine 31 Ship 32 Umbrella beam Scan Area 33 Fan Beam Scan Area 34 Fish School Image 34a-34c Fish School Image 35 Seabed Terrain Image 36 Contour Line 100 Scanning Sonar θ Tilt Angle φ Horizontal Azimuth Angle

Claims (9)

  1. Underwater that displays an image of underwater information in a scan area based on echoes transmitted from a transmitter to a wide range of underwater in the form of an umbrella beam and scanned in the predetermined direction. In the detection device,
    Generating three-dimensional echo display data from echo data obtained by the scan,
    An underwater detection device that displays underwater information in the scan area as a three-dimensional image on a display screen based on the echo display data.
  2. Underwater that displays an image of underwater information in a scan area based on echoes transmitted from a transmitter to a wide range of underwater in the form of an umbrella beam and scanned in the predetermined direction. In the detection device,
    Generating three-dimensional echo display data from echo data obtained by the scan,
    Based on the echo display data, underwater information in the scan area is displayed on a display screen as a virtual stereoscopic image similar to the umbrella beam having the transmitter as a vertex. .
  3. A first mode in which an ultrasonic signal is transmitted into the water and echoes are received by scanning in a first direction and a second mode in which echoes are received by scanning in a second direction are received. In an underwater detector that displays an image of underwater information in a scan area based on echo,
    Three-dimensional echo display data is generated from the echo data obtained by the scan in the first mode and the echo data obtained by the scan in the second mode,
    The three-dimensional video of underwater information based on the echo display data in the first mode and the three-dimensional video of underwater information based on the echo display data in the second mode are displayed on the display screen in a three-dimensional manner. A featured underwater detector.
  4. In an underwater detection device that transmits an ultrasonic signal into water and displays an image of underwater information in a scan area based on echoes received by scanning in a predetermined direction.
    Generating three-dimensional echo display data from echo data obtained by the scan,
    Save the echo display data for the number of scans,
    An underwater detection apparatus that displays a history of a three-dimensional image of a school of fish in the scan area based on the stored echo display data.
  5. The underwater detection device according to any one of claims 1 to 4,
    An underwater detection apparatus, wherein a 3D image of the scan area is displayed on a display screen so as to overlap the 3D image of the underwater information.
  6. In the underwater detection device according to claim 4 or 5,
    An underwater detection apparatus, comprising: threshold setting means for setting a threshold for an echo signal level, and displaying a history of a three-dimensional image of a school of fish only for an echo having a signal level equal to or higher than the set threshold.
  7. The underwater detection device according to any one of claims 1 to 6,
    An underwater detection device comprising transparency setting means for setting the transparency of a stereoscopically displayed image.
  8. The underwater detection device according to any one of claims 1 to 7,
    An underwater detection device characterized in that the viewpoint of a stereoscopically displayed image can be arbitrarily changed.
  9. The underwater detection device according to any one of claims 1 to 8,
    An underwater detection apparatus that displays a three-dimensional image of the water bottom terrain together with the three-dimensional image of the underwater information.
JP2004355959A 2004-12-08 2004-12-08 Underwater detection system Pending JP2006162480A (en)

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US9541643B2 (en) 2009-07-14 2017-01-10 Navico Holding As Downscan imaging sonar
JP2011247623A (en) * 2010-05-24 2011-12-08 Furuno Electric Co Ltd Detection device, scanning sonar, method for controlling detection device and program for detection device
JP2013011475A (en) * 2011-06-28 2013-01-17 Nec Network & Sensor Systems Ltd System, method, and program for acoustic image generation
US9142206B2 (en) 2011-07-14 2015-09-22 Navico Holding As System for interchangeable mounting options for a sonar transducer
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US9268020B2 (en) 2012-02-10 2016-02-23 Navico Holding As Sonar assembly for reduced interference
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US9354312B2 (en) 2012-07-06 2016-05-31 Navico Holding As Sonar system using frequency bursts
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