Ultrasonic sonar apparatus

Abstract

This ultrasonic sonar apparatus 1 includes a detection result image generation means 16 for generating a horizontal detection result image 22 indicating an underwater detection result 22a projected onto a plane parallel to a horizontal plane on the basis of received signals of reflected ultrasonic waves TB reflected from at least a direction set in the azimuth direction. The detection result image generation means 16 generates the horizontal detection result image 22 such that, in a region corresponding to a portion of the azimuth direction in the horizontal detection result image 22, a vertical detection result 22b based on received signals of reflected ultrasonic waves TB reflected from the vertical direction is indicated, instead of an underwater detection result 22a projected onto a plane parallel to a horizontal plane.

Description

Ultrasonic sonar device

[0001] The present invention relates to an ultrasonic sonar device mounted on a ship for detecting underwater objects within a predetermined range around the ship.

[0002] An ultrasonic sonar device that detects objects to be detected such as fish schools by transmitting and receiving ultrasonic waves over a predetermined range in water is known. A general fish school detection device detects objects to be detected in the vertical direction from a ship, while an ultrasonic sonar device can detect objects to be detected existing around the ship, such as horizontal detection and vertical cross-section detection. As ultrasonic sonar devices, for example, a PPI sonar (searchlight sonar) and a scanning sonar are known.

[0003] The PPI sonar irradiates (transmits) a thin beam-shaped ultrasonic wave, and a vibrator that receives the reflected wave from the object to be detected of the ultrasonic wave is configured to be rotatable or pivotable, and detects underwater objects around the ship while changing the irradiation direction of the ultrasonic wave (for example, Patent Document 1). Since the structure of the vibrator of the PPI sonar is simple, it can be configured at a low cost, but it takes time until one detection over a predetermined range is completed.

[0004] The scanning sonar forms a plurality of fine vibrators in an array shape on the surface of a cylinder, a sphere, etc., transmits ultrasonic waves simultaneously from each vibrator, and receives the reflected waves to detect underwater objects around the ship at once (for example, Patent Document 2). The scanning sonar can perform one detection over a predetermined range in a short time, but on the other hand, the vibrator array becomes complex, and the transmission / reception circuit for transmitting and receiving ultrasonic waves in each vibrator becomes large-scale, so it becomes expensive.

[0005] Japanese Patent Application Laid-Open No. 2019-066208, Japanese Patent Application Laid-Open No. 2019-200204

[0006] When performing horizontal detection in such an ultrasonic sonar device, it is common that the transmission / reception direction of the ultrasonic wave is set in a plurality of directions over a predetermined range with respect to the azimuth direction while being fixed at a predetermined depression angle. That is, in general, horizontal detection in an ultrasonic sonar device is performed from the ship obliquely downward.

[0007] On the other hand, ultrasonic sonar displays the detection results of horizontal detection as a circular image projected onto a plane parallel to the horizontal plane. This image can easily show the user the presence or absence of detected objects such as schools of fish within a predetermined range, as well as the direction in which the detected objects are located and how far they are horizontally from the vessel. However, as mentioned above, since the image is a projection of the detection results onto a plane parallel to the horizontal plane, there was a problem in that it was difficult for the user to intuitively grasp the depth at which the detected objects were located.

[0008] This invention was made to solve the above-mentioned problems, and aims to provide an ultrasonic sonar device that allows for an intuitive understanding of the depth of an object being detected in horizontal detection.

[0009] To achieve this objective, a first aspect of the present invention includes: a transmitter / receiver unit attached to a ship that transmits ultrasonic waves into the water over a predetermined range and is configured to receive reflected ultrasonic waves reflected from each position in the water for each predetermined direction including at least a plurality of directions set in the azimuthal direction and the vertical direction; a receiving signal generation means that generates a received signal for each predetermined direction based on the reflected waves received by the transmitter / receiver unit; a detection result image generation means that generates a detection result image showing the underwater detection results projected onto a plane parallel to the horizontal plane based on the received signals generated by the receiving signal generation means in at least the directions set in the azimuthal direction; and a display means that displays the detection result image generated by the detection result image generation means, wherein the detection result image generation means generates the detection result image such that a portion of the azimuthal region of the detection result image shows the vertical detection results based on the received signals generated by the receiving signal generation means in the vertical direction, rather than the underwater detection results projected onto a plane parallel to the horizontal plane.

[0010] A second aspect of the present invention is an ultrasonic sonar device according to the first aspect, wherein the detection result image generation means generates the detection result image such that the distance in the distance direction of the detection result in the water projected onto a plane parallel to the horizontal plane corresponds to the distance in the distance direction of the detection result in the vertical direction.

[0011] A third aspect of the present invention is an ultrasonic sonar device according to the first or second aspect, wherein the detection result image generation means generates the detection result image such that, in the vertical detection result, the stronger the intensity of the received signal, the longer the image is displayed in the direction perpendicular to the distance direction.

[0012] A fourth aspect of the present invention is an ultrasonic sonar device according to any of the first to third aspects, wherein the detection result image generation means generates the detection result image such that the vertical detection result is shown in the region corresponding to the rear side of the vessel in the detection result image.

[0013] A fifth aspect of the present invention is an ultrasonic sonar device according to any of the first to fourth aspects, comprising storage means for storing the received signals generated by the receiving signal generation means for each predetermined direction in a received signal array indexed by the direction and the distance at which the reflected ultrasonic wave that forms the basis of the received signal was generated, wherein the detection result image generation means has a conversion table showing the direction and distance of the received signal array corresponding to each coordinate of the detection result image, and generates the detection result image after identifying the level of the received signal at each coordinate of the detection result image from the received signal array based on the conversion table, wherein the conversion table associates each coordinate included in the region showing the underwater detection result projected onto a plane parallel to the horizontal plane with the direction set in the azimuth direction of the received signal array, and associates each coordinate included in the region showing the vertical detection result of the detection result image with the vertical direction.

[0014] A sixth aspect of the present invention is an ultrasonic sonar device according to the fifth aspect, wherein a virtual direction is provided in which a predetermined value is shown as the level of a virtual received signal for all distances in the distance direction, the conversion table associates the vertical direction or the direction between the vertical direction and the virtual direction with each coordinate included in the region showing the detection result in the vertical direction of the detection result image, and the detection result image generation means determines the level of the received signal at the coordinate by weighting the level of the received signal in the vertical direction and the predetermined value of the virtual direction based on the distance from the vertical direction and the virtual direction, respectively, for the coordinates in the conversion table to which the direction between the vertical direction and the virtual direction is associated.

[0015] According to the ultrasonic sonar device of the first aspect of the present invention, ultrasonic waves are transmitted into the water over a predetermined range by a transmitting and receiving unit attached to a ship, and reflected ultrasonic waves reflected from each position in the water are received for each predetermined direction, which includes at least a plurality of directions set in the azimuth direction and the vertical direction. Based on the reflected waves received by the transmitting and receiving unit, a received signal is generated by a received signal generation means for each predetermined direction. Based on the received signals for each predetermined direction generated by the received signal generation means, a detection result image is generated by a detection result image generation means, which projects the underwater detection result onto a plane parallel to the horizontal plane, and this detection result image is displayed by a display means. From this detection result image, the user can determine the presence or absence of a detected object, as well as the direction and horizontal distance of the detected object.

[0016] Here, in the detection result image, the detection result image is generated by the detection result image generation means so that in certain directional regions, the vertical detection result is shown based on the received signal generated by the received signal generation means in the vertical direction, rather than the underwater detection result projected onto a plane parallel to the horizontal plane. This allows the user to intuitively visualize the depth based on the vertical detection result shown in certain directional regions, in addition to the underwater detection result projected onto a plane parallel to the horizontal plane shown in the detection result image. Therefore, it has the effect of allowing users to intuitively grasp the depth of the object being detected in horizontal detection.

[0017] The ultrasonic sonar device according to the second embodiment provides the following effects in addition to the effects of the ultrasonic sonar device according to the first embodiment. Specifically, the detection result image generation means generates a detection result image so that the distance in the distance direction of the detection result in the water projected onto a plane parallel to the horizontal plane corresponds to the distance in the distance direction of the detection result in the vertical direction. Here, the distance in the distance direction of the detection result in the vertical direction is the depth. Therefore, the depth in the detection result in the water projected onto a plane parallel to the horizontal plane can be grasped more intuitively from the distance in the distance direction of the detection result in the vertical direction.

[0018] The ultrasonic sonar device according to the third embodiment provides the following effects in addition to the effects of the ultrasonic sonar device according to the first or second embodiment. Specifically, in the detection results in the vertical direction, the detection result image is generated by the detection result image generation means so that the stronger the received signal intensity, the longer the length displayed in the direction perpendicular to the distance direction. This has the effect of making it easier for the user to understand the depth at which a strong reaction occurred in the vertical direction.

[0019] The ultrasonic sonar device according to the fourth embodiment provides the following effect in addition to the effect of the ultrasonic sonar device according to any of the first to third embodiments. Specifically, in the detection result image, the detection result image is generated by the detection result image generation means so as to show the vertical detection result in the region corresponding to the rear side of the ship to which the transmitting and receiving unit is attached. Ships are equipped with screw propellers that provide thrust to propel them forward, and many bubbles are generated at the rear of the ship due to the high-speed rotation of the screw propellers. Since the ultrasonic waves transmitted from the transmitting and receiving unit are also reflected by these bubbles, in the underwater detection result projected onto a plane parallel to the horizontal plane, invalid results based on reflected waves from bubbles are often displayed on the rear side of the ship. By showing the vertical detection result instead of the underwater detection result projected onto a plane parallel to the horizontal plane in the region corresponding to the rear side of the ship in such a detection result image, it is possible to suppress the display of invalid detection results in the detection result image. Furthermore, by effectively utilizing the area where such invalid detection results are displayed to show vertical detection results, it is possible to intuitively grasp the depth of the object being detected in horizontal detection.

[0020] The ultrasonic sonar device according to the fifth embodiment provides the following effects in addition to the effects of the ultrasonic sonar device according to any of the first to fourth embodiments. Specifically, the received signals generated by the received signal generation means for each predetermined direction are stored in a received signal array indexed by the direction and the distance at which the reflected ultrasonic wave that forms the basis of the received signal was generated. Furthermore, a conversion table showing the direction and distance of the received signal array corresponding to each coordinate of the detection result image is provided in the detection result image generation means. Based on this conversion table, the level of the received signal at each coordinate of the detection result image is identified from the received signal array, and the detection result image generation means generates the detection result image. Here, in the conversion table, for each coordinate in the region of the detection result image showing the underwater detection result projected onto a plane parallel to the horizontal plane, the direction set in the azimuth direction of the received signal array is associated, and for each coordinate in the region of the detection result image showing the vertical detection result, the vertical direction is associated. As a result, the detection result image generation means can generate a detection result image based on a transformation table, and with only one coordinate transformation process, it can easily generate a detection result image that includes a region showing the underwater detection result projected onto a plane parallel to the horizontal plane, and a region showing the vertical detection result. Therefore, it has the effect of efficiently generating detection result images.

[0021] The ultrasonic sonar device according to the sixth embodiment provides the following effects in addition to those of the ultrasonic sonar device according to the fifth embodiment. Specifically, a virtual direction is provided in which a predetermined value is shown as the level of a virtual received signal for all distances in the distance direction, and in the conversion table, each coordinate included in the region showing the detection result in the vertical direction of the detection result image is associated with the vertical direction, or the direction between the vertical direction and the virtual direction. The detection result image generation means then determines the level of the received signal at a coordinate by weighting the level of the received signal in the vertical direction and the predetermined value of the virtual direction based on the distances from the vertical direction and the virtual direction, respectively, for the coordinates in the conversion table that are associated with the direction between the vertical direction and the virtual direction. As a result, the detection result image generation means can display the detection result over a long length in the direction perpendicular to the distance direction where the intensity of the received signal is strong in the vertical direction, simply by determining the level of the received signal according to the conversion table. Therefore, it has the effect of improving processing efficiency while more clearly communicating to the user the depth at which there was a strong reaction in the vertical direction.

[0022] This is a schematic diagram showing the configuration of an ultrasonic sonar device according to the first embodiment of the present invention. This is a schematic diagram showing the state when a ship equipped with the ultrasonic sonar device performs underwater detection, viewed from the side. (a) is a schematic cross-sectional view showing the transducer unit of the ultrasonic sonar device, and (b) is a schematic perspective view showing the arrangement of a plurality of first transducers and second transducers constituting the transducer unit. (a) is a schematic diagram showing the first central axis of each of the first transducers when viewed vertically from above the ship, (b) is a schematic diagram showing the first central axis when viewed horizontally from the front of the ship, (c) is a schematic diagram showing the directional characteristics of the ultrasonic waves transmitted from the first transducers, and (d) is a diagram showing the directional characteristics of the ultrasonic waves transmitted from the first transducers when viewed from the front of the ship. This is a schematic diagram showing an example of a display screen shown on the display device when the ultrasonic sonar device performs horizontal detection as a sonar function. This is a block diagram showing the electrical configuration of the ultrasonic sonar device. This figure schematically shows the contents of the received signal sequence stored in the storage means of the ultrasonic sonar device. This is a block diagram showing the electrical configuration of the ultrasonic sonar device according to the second embodiment of the present invention. This figure schematically shows the contents of the received signal sequence stored in the storage means of the ultrasonic sonar device. This figure schematically shows the conversion table of the detection result image generation means of the ultrasonic sonar device.

[0023] Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings. The embodiments described below are all preferred specific examples of the present invention. Therefore, the numerical values, shapes, materials, components, arrangement positions of components, and connection configurations shown in the following embodiments are examples and are not intended to limit the present invention. Accordingly, among the components in the following embodiments, those not described in the independent claims representing the highest-level concept of the present invention will be described as optional components. Furthermore, in each figure, substantially identical components are denoted by the same reference numerals, and redundant explanations are omitted or simplified.

[0024] (First Embodiment) First, an ultrasonic sonar device 1 according to the first embodiment, which is one embodiment of the present invention, will be described with reference to Figures 1 to 7. Figure 1 is a schematic diagram showing the configuration of the ultrasonic sonar device 1, and Figure 2 is a schematic diagram showing the state when underwater detection is performed by a ship 71 equipped with the ultrasonic sonar device 1, viewed from the side.

[0025] As shown in Figures 1 and 2, the ultrasonic sonar device 1 is mounted on a vessel 71 and has at least a sonar function that horizontally detects objects GF, such as schools of fish, in the water such as the sea, lake, or river in which the vessel 71 is floating, over a predetermined range around the vessel 71. Horizontal detection is performed by defining a predetermined range in all directions with respect to the azimuth as viewed from the vessel 71, and detecting objects GF that are included in that predetermined range.

[0026] In this embodiment, the predetermined range in which horizontal detection is performed is described as being omnidirectional with respect to the azimuth direction as viewed from the vessel 71. However, it is not necessarily required to be omnidirectional, and it may be limited to a portion of the azimuth direction as viewed from the vessel 71. Furthermore, the ultrasonic sonar device 1 may have a sonar function that performs vertical cross-sectional detection in addition to horizontal detection, or it may have a fish finder function that detects objects GF located in the vertical direction directly below the vessel 71 and displays the detection results in chronological order.

[0027] The ultrasonic sonar device 1 comprises a main body 5, an operation button 31 provided on the main body 5, a display device 21 integrally formed on the main body 5 as a display means, a transmitter / receiver unit 50 for transmitting and receiving ultrasonic waves TB for detecting a target object GF, and a lifting device 41 for raising and lowering the transmitter / receiver unit 50. The main body 5, the operation button 31, and the display device 21 are located in the wheelhouse of the ship 71, while the transmitter / receiver unit 50 and the lifting device 41 are located in the bottom of the ship 71. The transmitter / receiver unit 50 can be raised and lowered by the lifting device 41, allowing it to extend and retract from the bottom of the ship 71 into the water. The ultrasonic sonar device 1 does not necessarily have to have the lifting device 41, and the transmitter / receiver unit 50 may be fixed to the ship 71 in a position where ultrasonic waves TB can be transmitted and received toward the water.

[0028] The operation button 31 is a button that can be operated by the user, and is used when the user gives various instructions or settings to the ultrasonic sonar device 1. For example, the user can turn the power of the ultrasonic sonar device 1 on or off, set the detection mode (horizontal detection, vertical cross-sectional detection, fish detection, etc.) and detection range of the ultrasonic sonar device 1, and set the type and brightness of the image displayed by the display device 21, etc., by operating the operation button 31.

[0029] As shown in Figure 2, the ultrasonic sonar device 1 transmits (irradiates) ultrasonic waves TB in a conical shape over a predetermined range from the transmitting / receiving unit 50, with the transmitting / receiving unit 50 protruding from the bottom of the ship 71. The transmitting / receiving unit 50 is configured to receive reflected ultrasonic waves TB reflected from objects to be detected GF, or from the seabed or lakebed (hereinafter collectively referred to as "seabed SB"), etc., within that predetermined conical range. The detailed configuration of the transmitting / receiving unit 50 will be described later with reference to Figures 3 and 4.

[0030] The display device 21, together with the display control means 18 described later, constitutes the display means of the present invention. The display device 21 displays the detection result based on the received signal generated by the receiving units 13a to 13g and the filter 14 (see Figure 5), described later, when the transmitting / receiving unit 50 receives the reflected waves of the ultrasonic TB. The display device 21 is composed of, for example, a liquid crystal display or an organic EL (Electro-Luminescence) display. When the ultrasonic sonar device 1 performs horizontal detection using the search function, the display device 21 displays a horizontal detection result image 22 (see Figure 5) as the detection result image. Details of the horizontal detection result image 22 will be described later with reference to Figure 5.

[0031] Next, the detailed configuration of the transmitting / receiving unit 50 will be described with reference to Figures 3 and 4. Figure 3(a) is a schematic cross-sectional view showing the transmitting / receiving unit 50, and Figure 3(b) is a schematic perspective view showing the arrangement of the multiple first transducers 52 (52a to 52f) and the second transducer 53 that constitute the transmitting / receiving unit 50.

[0032] Furthermore, Figure 4(a) schematically shows the first central axes C1a to C1f of the first transducers 52a to 52f as viewed vertically from above the ship 71, and Figure 4(b) schematically shows the first central axes C1a to C1f of the first transducers 52a to 52f as viewed horizontally from the front side of the ship 71. Furthermore, Figure 4(c) schematically shows the directional characteristics of the ultrasonic TB transmitted from adjacent first transducers 52a, 52b, and 52f, and Figure 4(d) shows the directional characteristics of the ultrasonic TB transmitted from the first transducer 52a and the first transducer 52d as viewed from the front side of the ship 71.

[0033] As shown in Figure 3, the transmitting and receiving unit 50 has a structure in which a plurality of (six in the example shown in Figure 3) first transducers 52 (first transducer 52a, first transducer 52b, first transducer 52c, first transducer 52d, first transducer 52e, first transducer 52f) and a second transducer 53 are housed in a case 51 and molded. Each first transducer 52 is a disc-shaped structure having the same size and shape as the others. The second transducer 53 also has a disc shape similar to the first transducers 52. However, the size of the second transducer 53 is determined according to the required characteristics. That is, the second transducer 53 may be the same size as the first transducer 52, or it may be a different size from the first transducer 52.

[0034] Each of the first transducer 52 and the second transducer 53 comprises a base material 54 and a piezoelectric element 55. The base material 54 is a disc-shaped resin plate material that also serves as an acoustic matching layer, and for example, a glass epoxy base material is used.

[0035] The piezoelectric element 55 is a plate-shaped object made of piezoelectric ceramics, and for example, a disc-shaped plate-shaped object made of lead zirconate titanate (PZT) is used. The piezoelectric element 55 has a front side electrode (not shown) formed on the front surface, which is fully bonded to the substrate 54 via an adhesive layer (not shown), and a back side electrode (not shown) formed on the back surface facing the front surface. Lead wires are electrically connected to the front side electrode and the back side electrode, respectively.

[0036] When a driving voltage is applied to the piezoelectric element 55 by the front electrode and back electrode from the transmitting unit 11a or transmitting unit 11b (see Figure 5), which will be described later, it deforms in the thickness direction and vibrates the substrate 54. This vibration of the substrate 54 causes the first transducer 52 and the second transducer 53 to each generate ultrasonic TB.

[0037] Furthermore, when the substrate 54 vibrates due to the reflected waves of the ultrasonic TB, the piezoelectric element 55 of each of the first transducer 52 and the second transducer 53 deforms due to the vibration, and a voltage is generated between the front electrode and the back electrode. The first transducers 52a to 52f and the second transducer 53 each output the voltage generated between the front electrode and the back electrode to the corresponding receiving units 13a to 13g, which will be described later, thereby generating a received signal corresponding to the reflected waves received by each of the first transducers 52a to 52f and the second transducer 53.

[0038] The case 51 has an opening at one end, and a plurality of first resonators 52 and second resonators 53 are housed inside the case 51. The second resonator 53 is positioned in the center of the case 51. Six first resonators 52 are arranged around the second resonator 53 in the order of first resonator 52a, first resonator 52b, first resonator 52c, first resonator 52d, first resonator 52e, and first resonator 52f, in a counterclockwise direction when viewed from the front side of the base material 54. The acoustic radiation surfaces formed on the front surface of the base material 54 of each first resonator 52 and the acoustic radiation surfaces formed on the front surface of the base material 54 of the second resonator 53 are all located on a single virtual sphere.

[0039] In this embodiment, six first transducers 52 are used, but the number of first transducers 52 may be any number of three or more, preferably four or more, and more preferably six or more. However, if the number of first transducers 52 increases, the configuration of the ultrasonic sonar device 1 becomes more complex, larger, and more expensive, so it is preferable that the number of first transducers 52 be 10 or less, and more preferably 8 or less.

[0040] Here, for the first transducer 52a, the direction of the first central axis C1a, which is a central axis perpendicular to the center of the front surface (acoustic radiation surface) of the substrate 54 (which can also be called the direction of the normal vector of the first transducer 52a), can be understood as the acoustic radiation direction. Similarly to the first transducer 52a, the first transducer 52b has a first central axis C1b, the first transducer 52c has a first central axis C1c, the first transducer 52d has a first central axis C1d, the first transducer 52e has a first central axis C1e, and the first transducer 52f has a first central axis C1f. Then, each of the first central axes C1b to C1f can be understood as the acoustic radiation direction of the corresponding first transducers 52b to 52f.

[0041] Furthermore, the direction of the second central axis C2, which is a central axis perpendicular to the center of the front surface (acoustic radiation surface) of the substrate 54 (which can also be called the direction of the normal vector of the second transducer 53), can be understood to be the acoustic radiation direction.

[0042] That is, the first central axes C1a to C1f of each of the first transducers 52a to 52f and the second central axis C2 of the second transducer 53 are in a predetermined direction for transmitting ultrasonic waves TB and receiving their reflected waves within a predetermined range which is the detection range of the object GF to be detected.

[0043] Here, the transmitting and receiving unit 50 is mounted on the ship 71 such that the direction of the second central axis C2 of the second transducer 53 is vertical. That is, the second transducer 53 transmits (irradiates) ultrasonic TB in the vertical direction directly below the ship 71. Due to the presence of this second transducer 53, the ultrasonic sonar device 1 can detect objects GF in the vertical direction with high accuracy. It is preferable that the directional characteristics of the ultrasonic TB transmitted from the second transducer 53 be such that its directional angle is small and it forms a narrow beam. This further improves the accuracy of detecting objects GF in the vertical direction.

[0044] On the other hand, as shown in FIG. 3, in the transmitting / receiving wave unit 50, the acoustic radiation surfaces of the respective first vibrators 52a to 52f are inclined such that the first central axes C1a to C1f form a predetermined angle ω with respect to the second central axis C2 (that is, the vertical direction in the situation where the transmitting / receiving wave unit 50 is attached to the ship 71), and the first vibrators 52a to 52f are respectively arranged. As a result, as shown in FIG. 4(b), the acoustic radiation directions of the respective first vibrators 52a to 52f are directed in directions different from the vertical direction directly below the ship 71.

[0045] In the present embodiment, the respective first vibrators 52a to 52f are inclined and arranged with their acoustic radiation surfaces facing inward (toward the side where the second vibrator 53 is located) (see FIG. 3). At this time, the first central axes C1a to C1f preferably form one angle selected from the range of 20° or more and 50° or less as a predetermined angle ω with respect to the second central axis C2 respectively. In the present embodiment, the predetermined angle ω is 30°. As shown in FIG. 3(a), the respective first central axes C1a to C1f and the second central axis C2 are in a state of converging at one point.

[0046] Further, when the transmitting / receiving wave unit 50 is attached to the ship 71 and viewed vertically from above the ship 71, the respective first central axes C1a to C1f of the first vibrators 52a to 52f are arranged at equal intervals in the azimuth direction such that the angle formed by adjacent first central axes C1a to C1f is the same angle δ as shown in FIG. 4(a). When the number of the first vibrators 52 is n, the angle δ is (360 / n)° (when the number of the first vibrators 52 is 6, the angle δ is 60°).

[0047] As a result, the transmitting / receiving wave unit 50 can simultaneously transmit ultrasonic waves TB in each of the predetermined directions indicated by the first central axes C1a to C1f by at least the first vibrators 52a to 5Af over a predetermined range set in all directions of the ship 71, and can receive reflected waves in each of the predetermined directions.

[0048] In addition, in the present embodiment, as shown in FIGS. 4(a) and 4(b), when the ship 71 is viewed vertically from above, the first central axis C1a is directed to the right with respect to the longitudinal direction of the ship 71, and the first central axes C1b to C1f are arranged at intervals of an angle δ counterclockwise in order from the first central axis C1a, and the transmitting and receiving unit 50 is attached to the ship 71. Further, in the present embodiment, an example is shown in which the first oscillators 52a to 52f are arranged such that the first central axes C1a to C1f of the respective first oscillators 52a to 52f are equally spaced in the azimuth direction. However, as long as the ultrasonic waves TB can be transmitted simultaneously in each predetermined direction indicated by the first central axes C1a to C1f by at least the first oscillators 52a to 52f over a predetermined range set in all directions of the ship 71, the intervals between the first central axes C1a to C1f may vary. The directions of the first central axes C1a to C1f set as described above correspond to the "plurality of directions set in the azimuth direction" of the present invention.

[0049] The directivity characteristics of the ultrasonic waves TB transmitted from the respective first oscillators 52a to 52f are set so as to include the first central axes C1a to C1f of the adjacent first oscillators 52. For example, as shown in FIG. 4(c), the directivity characteristics of the ultrasonic waves TB transmitted from the first oscillator 52a are set so as to include the first central axis C1b of the adjacent first oscillator 52b and the first central axis C1f of the first oscillator 52f.

[0050] On the other hand, the directivity characteristics of the ultrasonic waves TB transmitted from the first oscillator 52b and the directivity characteristics of the ultrasonic waves TB transmitted from the first oscillator 52f are also set so as to include the first central axis C1a of the first oscillator 52a. Although not shown, the directivity characteristics of the ultrasonic waves TB transmitted from the first oscillator 52b are also set so as to include the first central axis C1c of the first oscillator 52c adjacent to the opposite side of the first oscillator 52a, and the directivity characteristics of the ultrasonic waves TB transmitted from the first oscillator 52f are also set so as to include the first central axis C1e of the first oscillator 52e adjacent to the opposite side of the first oscillator 52a.

[0051] Furthermore, as shown in FIG. 4(d), the directivity characteristics of the ultrasonic waves TB transmitted from the respective first oscillators 52a to 52f are set so as to include the vertical direction in any situation where the transmitting and receiving unit 50 is attached to the ship 71.

[0052] As described above, the ultrasonic TB transmitted from each of the first transducers 52a to 52f is set to have directional characteristics that include the first central axes C1a to C1f of adjacent first transducers 52, and also include the vertical direction when the transmitting / receiving unit 50 is attached to the ship 71. As a result, the transmitting / receiving unit 50 drives each of the first transducers 52a to 52f simultaneously, so that ultrasonic TB is irradiated from each of the first transducers 52a to 52f in the direction of their respective first central axes C1a to C1f, and the directional characteristics of the ultrasonic TB allow the ultrasonic TB to be transmitted simultaneously to a predetermined range set in all directions of the ship 71 with a small number of first transducers 52.

[0053] Furthermore, each of the first transducers 52a to 52f has a fixed direction of the first central axis C1a to C1f and a fixed directional characteristic of the ultrasonic TB emitted from each of the first transducers 52a to 52f, so that ultrasonic TB is irradiated from the transmitting / receiving unit 50 over a predetermined range. Therefore, circuits for controlling the direction of the first central axis C1a to C1f in the first transducers 52a to 52f, and circuits for controlling the directional characteristic of the ultrasonic TB emitted from each of the first transducers 52a to 52f, can be eliminated.

[0054] Furthermore, the transmitting and receiving unit 50 can receive the reflected waves of ultrasonic waves TB reflected from the object GF to be detected within a predetermined range, for each of the first central axes C1a to C1f, which are in a predetermined direction, using the first transducers 52a to 52f corresponding to each of the first central axes C1a to C1f. As a result, the ultrasonic sonar device 1 can be constructed to perform high-speed detection in a compact and low-cost manner.

[0055] The transmitting and receiving unit 50 is arranged and housed in a case 51 with the first transducers 52a to 52f and the second transducer 53 closely packed together, such that the first central axes C1a to C1f and the second central axis C2 are oriented in the directions described above, and are fixed in place with a filler. The filler used is a resin material (for example, urethane resin) that has a lower inherent acoustic impedance than the base material 54, which is the acoustic matching layer of the first transducer 52 and the second transducer 53, and is waterproof. The outer surface of the filler is filled so that it is flush with the opening of the case 51, thereby closing the opening of the case 51.

[0056] Next, with reference to Figure 5, the horizontal detection result image 22 will be explained. Figure 5 is a schematic diagram showing an example of the display screen displayed on the display device 21 when the ultrasonic sonar device 1 performs horizontal detection as a sonar function.

[0057] As shown in Figure 5, when the ultrasonic sonar device 1 performs horizontal detection as a sonar device, the display device 21 mainly displays the horizontal detection result image 22. In addition, when the ultrasonic sonar device 1 performs horizontal detection, it may also display one or more detection result images on the display device 21, in addition to the horizontal detection result image 22, which are time-series images of detection results in the distance direction from the transmitting / receiving unit 50 based on a received signal in at least one direction (in the example in Figure 5, this applies to each of the two detection result images displayed vertically in the left area of ​​the display device 21). Furthermore, detection result images other than the horizontal detection result image 22 may be displayed or hidden on the display device 21 by the user operating the operation button 31. Note that detection result images other than the horizontal detection result image 22 are not necessarily required for the present invention, so their explanation is omitted here.

[0058] The horizontal detection result image 22 is a circular (or fan-shaped) detection result image obtained by projecting the latest underwater detection results 22a for each direction onto a plane parallel to the horizontal plane, based on horizontal detection performed from the ship 71 in all directions (or some directions). Specifically, based on the received signals for each direction of the first central axes C1a to C1f of the first transducers 52a to 52f, the latest underwater detection results 22a (hereinafter also referred to as "underwater detection results 22a projected onto a plane parallel to the horizontal plane") over a predetermined range set in all directions of the ship 71 are displayed on the display device 21 as a horizontal detection result image 22 projected onto a plane parallel to the horizontal plane.

[0059] The user of the ultrasonic sonar device 1 can easily determine, from the horizontal detection result image 22 displayed on the display device 21, the current direction of the detected object GF relative to the ship 71, and how far it is horizontally from the ship 71 (what is the horizontal distance), etc., based on the underwater detection result 22a projected onto a plane parallel to the horizontal plane.

[0060] Furthermore, the horizontal detection result image 22 shows the vertical detection result 22b relative to the vessel 71 in a certain azimuthal region (in the example shown in Figure 5, the region corresponding to the rear side of the vessel 71), rather than the underwater detection result 22a projected onto a plane parallel to the horizontal plane. Specifically, based on the received signal in the direction of the second central axis C2 of the second transducer 53, the vertical detection result 22b of the vessel 71 is shown in a certain azimuthal region of the horizontal detection result image 22.

[0061] This allows the user to intuitively visualize the depth based on the vertical detection results 22b shown in a certain directional region, relative to the underwater detection results 22a projected onto a plane parallel to the horizontal plane shown in the horizontal detection result image 22. Thus, the depth of the object GF detected in horizontal detection can be intuitively grasped.

[0062] Here, the horizontal detection result image 22 is generated so that the distance in the distance direction of the underwater detection result 22a projected onto a plane parallel to the horizontal plane (the direction of radiation of ultrasonic TB from the first transducer 52, i.e., the direction along the first central axis C1a to C1f) corresponds to the distance in the distance direction of the vertical detection result 22b (the direction of radiation of ultrasonic TB from the second transducer 53, i.e., the direction along the second central axis C2). The underwater detection result 22a projected onto a plane parallel to the horizontal plane mainly reflects detection results at deeper depths as it moves further away from the vessel 71 along the distance direction (the further away from the center of the circle in the horizontal detection result image 22). On the other hand, the distance in the distance direction of the vertical detection result 22b is the depth itself. The horizontal detection result image 22 displays the respective detection results 22a and 22b such that the depth of the detection result, which is mainly represented at each position in the distance direction of the underwater detection result 22a projected onto a plane parallel to the horizontal plane, matches the depth of the detection result, which is represented at each position in the distance direction of the vertical detection result 22b. This allows the user to more accurately understand the depth of each position in the underwater detection result 22a projected onto a plane parallel to the horizontal plane, based on the depth, which is the distance in the distance direction of the vertical detection result 22b.

[0063] Furthermore, the horizontal detection result image 22 may display the respective detection results 22a and 22b such that the slant distance (distance along the direction of radiation of ultrasonic waves TB from the first transducer 52, i.e., the distance along the first central axis C1a to C1f) at each position in the distance direction of the underwater detection result 22a projected onto a plane parallel to the horizontal plane matches the distance (depth) in the distance direction of the vertical detection result 22b.

[0064] In this case, the depth of the detection result, primarily represented at each position in the distance direction of the underwater detection result 22a projected onto a plane parallel to the horizontal plane, and the depth of the detection result, represented at each position in the distance direction of the vertical detection result 22b, will not exactly match. However, it is possible to give the user an intuitive image of the depth at each position in the underwater detection result 22a projected onto a plane parallel to the horizontal plane. Then, by associating the received signals where the time from the first transducer 52 transmitting the ultrasonic TB to the first transducer 52 receiving the reflected wave matches the time from the second transducer 53 transmitting the ultrasonic TB to the second transducer 53 receiving the reflected wave, and generating the underwater detection result 22a projected onto a plane parallel to the horizontal plane and the vertical detection result 22b, it is easy to obtain a horizontal detection result image 22 where the slant distance at each position in the distance direction of the underwater detection result 22a projected onto a plane parallel to the horizontal plane matches the distance (depth) in the distance direction of the vertical detection result 22b.

[0065] The horizontal detection result image 22 should be generated such that, in the vertical detection result 22b, the stronger the level (intensity) of the received signal of the reflected wave received from each depth, the longer the corresponding depth is displayed in the azimuth direction, which is perpendicular to the distance direction. This makes it easier to convey to the user the depth at which there was a strong reaction in the vertical direction. Furthermore, a strong reaction is caused by a school of fish formed by large fish or many fish. By generating the horizontal detection result image 22 such that, in the vertical detection result 22b, the stronger the level (intensity) of the received signal of the reflected wave received from each depth, the longer the corresponding depth is displayed in the azimuth direction, which is perpendicular to the distance direction, it becomes easier for the user to visualize the presence of a school of fish formed by large fish or many fish at that location.

[0066] Furthermore, the horizontal detection result image 22 is preferably generated to show the vertical detection result 22b in the area corresponding to the rear side of the vessel 71 to which the transducer unit 50 is attached, as shown in Figure 5. The vessel 71 is equipped with a screw propeller (not shown) that provides thrust for forward propulsion, and many bubbles are generated at the rear of the vessel 71 due to the high-speed rotation of the screw propeller. Since the ultrasonic TB transmitted from the transducer unit 50 is also reflected by these bubbles, in the underwater detection result 22a projected onto a plane parallel to the horizontal plane, invalid results based on reflected waves from the bubbles are often displayed at the rear of the vessel 71.

[0067] In the area corresponding to the rear of the vessel 71 in such a horizontal detection result image 22, by displaying the vertical detection result 22b instead of the underwater detection result 22a projected onto a plane parallel to the horizontal plane, it is possible to suppress the display of invalid detection results in the horizontal detection result image 22. Furthermore, by effectively utilizing the area where such invalid detection results are displayed to display the vertical detection result 22b, the depth of the object GF detected in the horizontal detection can be intuitively grasped.

[0068] Next, the electrical configuration of the ultrasonic sonar device 1 will be described with reference to Figure 6. Figure 6 is a block diagram showing the electrical configuration of the ultrasonic sonar device 1. Inside the main body 5 of the ultrasonic sonar device 1 is a control device 10, which is equipped with transmitting units 11a, 11b, diodes 12a to 12g, receiving units 13a to 13g, a filter 14, storage means 15, detection result image generation means 16, and display control means 18.

[0069] Each of the transmitting units 11a, 11b, receiving units 13a to 13g, filter 14, detection result image generation means 16, and display control means 18 may be configured in hardware, implemented in software, or implemented through the cooperation of hardware and software.

[0070] Although not shown in the diagram, the control device 10 includes a CPU (Central Processing Unit), a flash memory (a rewritable, non-volatile memory) and / or a ROM (Read Only Memory) (a non-rewritable, non-volatile memory) that stores programs executed by the CPU and fixed values ​​referenced by those programs, and a RAM (Random Access Memory) (a read-write, volatile memory) that temporarily stores various data when the CPU executes a program. These are connected via a bus line.

[0071] Of the transmitting units 11a, 11b, receiving units 13a to 13g, filter 14, detection result image generation means 16, and display control means 18, the parts implemented by software or through the cooperation of hardware and software are implemented by the CPU executing a program. The storage means 15 is built into RAM.

[0072] Based on instructions from the CPU, the transmitting unit 11a generates a single drive signal to transmit ultrasonic TB from the first transducers 52a to 52f. The output of the single drive signal generated by the transmitting unit 11a is branched between the transmitting unit 11a and diodes 12a to 12f and distributed to each of the first transducers 52a to 52f. Specifically, one branch is input to the first transducer 52a via diode 12a, one via diode 12b to the first transducer 52b, one via diode 12c to the first transducer 52c, one via diode 12d to the first transducer 52d, one via diode 12e to the first transducer 52e, and one via diode 12f to the first transducer 52f.

[0073] Diodes 12a to 12f each allow the drive signal generated by the transmitting unit 11a to pass through and input to the corresponding first oscillators 52a to 52f, and are also elements that block the signal (voltage) generated by receiving the reflected wave in each of the first oscillators 52a to 52f from being transmitted to the transmitting unit 11a or to the branching point of the drive signal output from the transmitting unit 11a to each of the first oscillators 52a to 52f.

[0074] A single drive signal generated by the transmitting unit 11a is branched and input to the first transducers 52a to 52f via diodes 12a to 12f. As a result, each of the first transducers 52a to 52f, which have the same shape and size, are driven simultaneously and can output ultrasonic TB of the same intensity at the same timing. Therefore, ultrasonic TB can be transmitted uniformly in a predetermined direction (i.e., the direction of the first central axis C1a to C1f) within a predetermined range set in all directions relative to the ship 71, making the detection sensitivity uniform in all predetermined directions.

[0075] Furthermore, since one transmitting unit 11a is provided for multiple first transducers 52a to 52f, significant cost reduction and miniaturization can be achieved compared to the case where each first transducer 52a to 52f has its own transmitting unit 11a.

[0076] Furthermore, diodes 12a to 12f are provided at the downstream side of the branching point between the transmitting unit 11a and each of the first transducers 52a to 52f, where the drive signal output from the transmitting unit 11a branches out toward each of the first transducers 52a to 52f. This prevents the signals (voltages) output by each of the first transducers 52a to 52f upon receiving the reflected waves of the ultrasonic TB from flowing back to the transmitting unit 11a or from interfering with the signal lines of other first transducers 52a to 52f via the branching point. Therefore, even if one transmitting unit 11a is provided for multiple (six) first transducers 52a to 52f, the independence of the signals (voltages) output from each of the first transducers 52a to 52f can be ensured.

[0077] The transmitting unit 11b generates a drive signal to transmit ultrasonic TB from the second transducer 53 based on instructions from the CPU. The output of the drive signal generated by the transmitting unit 11b is input to the second transducer 53 via the diode 12g. The diode 12g is an element that allows the drive signal generated by the transmitting unit 11b to pass through and input to the second transducer 53, and also blocks the signal (voltage) generated when the second transducer 53 receives the reflected wave from being transmitted to the transmitting unit 11b. This diode 12g prevents the signal (voltage) output by the second transducer 53 when it receives the reflected wave of ultrasonic TB from flowing back to the transmitting unit 11b.

[0078] The ultrasonic sonar device 1 is provided with a transmitting unit 11b that generates a drive signal for the second transducer 53, which transmits ultrasonic TB in the vertical direction directly below the ship 71, independently of the transmitting unit 11a that generates drive signals for the first transducers 52a to 52f. This allows the ultrasonic sonar device 1 to function as a normal fish finder by turning off the transmission of ultrasonic TB from the first transducers 52a to 52f and transmitting ultrasonic TB only from the second transducer 53, or to control the transmission of ultrasonic TB from the second transducer 53 independently of the transmission of ultrasonic TB from the first transducers 52a to 52f when performing horizontal detection as a sonar function.

[0079] In this embodiment, a transmitting unit 11a corresponding to the first transducers 52a to 52f and a transmitting unit 11b corresponding to the second transducer 53 are provided separately. However, if the specifications of the ultrasonic sonar device 1 allow for the transmission of ultrasonic TB from the second transducer 53 to always occur at the same timing as the first transducers 52a to 52f, then only one transmitting unit 11a may be provided for the first transducers 52a to 52f and the second transducer 53, and a single drive signal may be generated from this transmitting unit 11a. This would allow for further significant cost reduction and miniaturization of the ultrasonic sonar device 1.

[0080] Receiving units 13a to 13g are provided for each of the multiple (six) first transducers 52a to 52f and second transducer 53. At predetermined time intervals after the corresponding first transducers 52a to 52f and second transducers 53 transmit ultrasonic TB, receiving units 13a to 13g capture signals (voltages) output according to the intensity of the reflected ultrasonic TB received by the first transducers 52a to 52f and second transducers 53, and perform sampling by applying predetermined processing to the captured signals.

[0081] Specifically, receiving unit 13a is connected to the first transducer 52a and receives a signal (voltage) output according to the intensity of the reflected wave received by the first transducer 52a, and performs predetermined processing. Similarly, receiving unit 13b is connected to the first transducer 52b, receiving unit 13c is connected to the first transducer 52c, receiving unit 13d is connected to the first transducer 52d, receiving unit 13e is connected to the first transducer 52e, receiving unit 13f is connected to the first transducer 52f, and receiving unit 13g is connected to the second transducer 53. Each receiving unit 13b to 13g also receives a signal (voltage) output according to the intensity of the reflected wave received by the connected first transducers 52b to 52f or the second transducer 53, and performs predetermined processing.

[0082] Each receiving unit 13a to 13g has an amplification circuit and an analog-to-digital conversion circuit. Each receiving unit 13a to 13g samples the signal (voltage) output from the corresponding first transducer 52a to 52f or second transducer 53 at predetermined intervals after the ultrasonic TB has been transmitted from the corresponding first transducer 52a to 52f or second transducer 53. Specifically, at predetermined intervals, as a predetermined process, each receiving unit 13a to 13g amplifies the signal (voltage) acquired from the corresponding first transducer 52a to 52f or second transducer 53 using an amplification circuit, and then converts it into a digital signal (digital value) using an analog-to-digital conversion circuit (AD conversion circuit).

[0083] Then, the receiving unit 13a outputs the digital signal obtained by the AD conversion circuit to the filter 14 as the received signal (received signal of the reflected wave of the ultrasonic TB) received by the first transducer 52a. Similarly, the receiving unit 13b outputs the digital signal obtained by the respective AD conversion circuit to the filter 14 as the received signal of the first transducer 52b, the receiving unit 13c outputs the digital signal obtained by the first transducer 52c, the receiving unit 13d outputs the digital signal obtained by the first transducer 52d, the receiving unit 13e outputs the digital signal obtained by the first transducer 52e, the receiving unit 13f outputs the digital signal obtained by the first transducer 52f, and the receiving unit 13g second transducer 53.

[0084] As described above, one transmitting unit 11a is provided for each of the multiple (six) first transducers 52a to 52f to reduce costs and miniaturize the device. In contrast, by providing a receiving unit 13a to 13f for each of the multiple first transducers 52a to 52f, the independence of the signals (voltages) output from each of the first transducers 52a to 52f can be maintained while applying predetermined processing to each signal (voltage). On the other hand, since the ultrasonic sonar device 1 has fewer transducers than conventional scanning sonars, even if a receiving unit 13a to 13f is provided for each of the first transducers 52a to 52f, the overall receiving unit can be made smaller and costs can be reduced compared to conventional scanning sonars.

[0085] The received signals output from the receiving units 13a to 13g are original received signals that represent the raw intensity values ​​of the reflected ultrasonic TB waves received by the corresponding first transducers 52a to 52f and the second transducer 53, respectively. This means that the original received signals are the received signals before filtering by the filter 14, which will be described next.

[0086] The filter 14 performs a predetermined filtering process on the received signals (original received signals) output from the receiving units 13a to 13g for each of the first oscillators 52a to 52f and the second oscillator 53. The predetermined filtering process may include spatial filtering and / or temporal filtering.

[0087] As for spatial filtering, for the purpose of reducing noise and / or improving resolution, filtering is performed in the azimuth and distance directions on the original received signals of each first transducer 52a to first transducer 52f that have received reflected ultrasonic TB waves for each predetermined direction. Furthermore, spatial filtering also includes filtering in the distance direction on the original received signal of the second transducer 53 that has received reflected ultrasonic TB waves from the vertical direction directly below the ship 71.

[0088] Here, the azimuth direction is the direction in which the first central axes C1a to C1f of the first transducers 52a to 52f, that is, the direction in which their respective acoustic radiation directions are aligned, or in other words, the circumferential direction centered on the ship 71. The distance direction is the direction in which the ultrasonic TB is transmitted at the first central axes C1a to C1f of the first transducers 52a to 52f, and at the second central axis C2 of the second transducer 53, that is, the respective acoustic radiation directions themselves.

[0089] Furthermore, when the ultrasonic sonar device 1 performs horizontal detection using its sonar function, it uses a small number of transducers (six in this embodiment), namely the first transducers 52a to 52f, which significantly reduces the azimuth resolution. Therefore, in horizontal detection, the filter 14 may set a virtual direction at an intermediate position between adjacent first central axes C1a to C1f of the first transducers 52a to 52f, which are predetermined directions in which ultrasonic TB is transmitted and received, and generate a received signal from the received signals of the first transducers 52a to 52f, assuming that ultrasonic TB was virtually transmitted and received in that virtual direction.

[0090] By generating a virtual received signal in a virtual direction, the number of directions in which ultrasonic TB is transmitted and received, including the virtual direction, can be double the actual number of first transducers 52 (12 directions in this embodiment), thereby improving the azimuth resolution.

[0091] As for spatial filtering, for the purpose of reducing noise and / or improving resolution, filtering is performed in the azimuth and distance directions on the original received signals of each first transducer 52a to first transducer 52f that have received reflected ultrasonic TB waves for each predetermined direction. Furthermore, spatial filtering also includes filtering in the distance direction on the original received signal of the second transducer 53 that has received reflected ultrasonic TB waves from the vertical direction directly below the ship 71.

[0092] On the other hand, temporal filtering is performed on a received signal indicating the intensity of a reflected wave reflected from a certain distance (or depth) in a certain direction, in conjunction with at least one received signal received earlier in time and / or at least one received signal received later in time, both from the same direction and the same distance (or depth). This temporal filtering allows the horizontal detection result image 22, described later, displayed on the display device 21 to change smoothly over time, enabling the user to view the horizontal detection result image 22 without any discomfort.

[0093] The filter 14 performs a predetermined filtering process on the original received signals of each of the first oscillators 52a to 52f and the second oscillator 53. The filter 14 then stores the values ​​obtained from the filtering process in the storage means 15 as the received signals of each of the first oscillators 52a to 52f and the second oscillator 53, and also includes the virtual received signals if a virtual received signal is generated for a virtual direction. The receiving units 13a to 13g and the filter 14 constitute the received signal generation means of the present invention.

[0094] The storage means 15 stores the filtered received signals of the first oscillators 52a to 52f and the second oscillator 53, respectively (i.e., in the directions of the first central axis C1a to C1f and the second central axis C2), generated by the filter 14, in the received signal array 15a. If a virtual received signal is generated for a virtual direction, that virtual received signal is also stored in the received signal array 15a for each virtual direction.

[0095] Here, with reference to Figure 7, the details of the received signal array 15a will be explained. Figure 7 is a schematic diagram showing the contents of the received signal array 15a. Note that, for the sake of simplicity, Figure 7 shows the received signal array 15a when the filter 14 does not generate virtual received signals in the virtual directions. When the filter 14 generates virtual received signals in the virtual directions, the received signal array 15a also stores the virtual received signals for each virtual direction.

[0096] The received signal array 15a is a two-dimensional array indiced by the direction θ in which the reflected waves of the ultrasonic TB that form the basis of the received signal were received (i.e., the directions of the first central axes C1a to C1f and the second central axis C2) and the distance R from the transmitting / receiving unit 50 to the position where the reflected waves of the ultrasonic that form the basis of the received signal were generated. In other words, the received signal array 15a stores the intensity (level) of the reflected waves reflected from each position specified by polar coordinates consisting of direction θ and distance R as the level of the received signal.

[0097] For each of the first central axes C1a to C1f, which are the directions for receiving reflected waves of the ultrasonic TB set in the azimuth direction, the numbers "1" to "6" are assigned in a clockwise direction from the front of the vessel 71 when viewed vertically from above the vessel 71. That is, in direction θ, "1" indicates the direction of the first central axis C1b, "2" indicates the direction of the first central axis C1a, "3" indicates the direction of the first central axis C1f, "4" indicates the direction of the first central axis C1e, "5" indicates the direction of the first central axis C1d, and "6" indicates the direction of the first central axis C1c. In addition, "7" is assigned to the second central axis C2, which is in the vertical direction. That is, in direction θ, "7" indicates the direction of the second central axis C2.

[0098] Furthermore, if one virtual direction is set between each of the two first central axes C1, and a virtual received signal for each virtual direction is generated by the filter 14, then as the direction θ, for example, the first central axis C1b is "1", the virtual direction between the first central axis C1b and the first central axis C1a is "2", the first central axis C1a is "3", the virtual direction between the first central axis C1a and the first central axis C1f is "4", and the first central axis C1f is " It is preferable that the virtual direction between the first central axis C1f and the first central axis C1e be assigned "6", the first central axis C1e be assigned "7", the virtual direction between the first central axis C1e and the first central axis C1d be assigned "8", the first central axis C1d be assigned "9", the virtual direction between the first central axis C1d and the first central axis C1c be assigned "10", the first central axis C1c be assigned "11", and the virtual direction between the first central axis C1c and the first central axis C1b be assigned "12". In this case, it is preferable that the direction θ of the second central axis C2, which is vertical, be assigned "13".

[0099] On the other hand, the distance R is assigned a number from "1" to "100". Then, in the first transducers 52a to 52f or the second transducer 53 corresponding to each direction θ, sampling is performed in the corresponding receiving units 13a to 13g at predetermined time intervals after the ultrasonic TB is transmitted, and when a received signal is output, the numbers from "1" to "100" are assigned to the output received signal one by one in ascending order. As is known, the elapsed time since the ultrasonic TB was transmitted is proportional to the distance to the position where the ultrasonic TB was reflected. Therefore, the distance R assigned in this way can indicate the distance from the transmitting / receiving unit 50 to the position where the ultrasonic TB was reflected.

[0100] The storage means 15 stores the level RSL(R, θ) of the received signal of the reflected wave reflected from a position specified by direction θ and distance R in the element of the received signal array 15a specified by direction θ and distance R. For example, the level RSL(1, 1) of the first received signal sampled for the first transducer 52b, which transmits and receives ultrasonic TB in the direction of the first central axis C1b, is stored in the gist of the received signal array 15a indicated by the index of direction θ = "1" and distance R = "1". Similarly, the level RSL(100, 7) of the 100th received signal sampled for the second transducer 53, which transmits and receives ultrasonic TB in the direction of the second central axis C2 (vertical direction), is stored in the element of the received signal array 15a indicated by the index of direction θ = "7" and distance R = "100".

[0101] Returning to Figure 6, the explanation continues. The detection result image generation means 16 uses the received signal array 15a stored in the storage means 15 to generate a horizontal detection result image 22 to be displayed on the display device 21 when the ultrasonic sonar device 1 performs horizontal detection as a sonar function. The detection result image generation means 16 has a horizontal detection result image generation means 16a and a vertical detection result image generation means 16b. The horizontal detection result image generation means 16a generates the underwater detection result 22a projected onto a plane parallel to the horizontal plane from the horizontal detection result image 22.

[0102] Here, the detection result image generation means 16 manages the position of each pixel in the horizontal detection result image 22 in a Cartesian coordinate system consisting of X coordinates and Y coordinates. The horizontal detection result image generation means 16a has a conversion table that associates the coordinates (X, Y) indicating the position of each pixel in the horizontal detection result image 22 with the coordinates (R, θ) in a polar coordinate system consisting of direction θ, which is an index of the received signal array 15a, and distance R, which correspond to those coordinates (X, Y). Note that the direction θ associated in the conversion table is 1 ≤ θ < 7. Here, the direction indicated by 6 ≤ θ < 7 means the direction included from the direction θ indicated by "6" (direction of the first central axis C1c) to the direction θ indicated by "1" (direction of the first central axis C1b). In other words, this conversion table only associates the direction θ in the azimuth direction.

[0103] The horizontal detection result image generation means 16a uses a conversion table to identify the polar coordinate system coordinates (R, θ) corresponding to the coordinates (X, Y) of each pixel. Then, for each pixel, the detection result image generation means 16 identifies the level of the received signal at the position of the coordinates (R, θ) identified for that pixel from the received signal array 15a stored in the storage means 15, and sets the identified level of the received signal as the level of the received signal for that pixel. In this way, the horizontal detection result image generation means 16a can identify the level of the received signal for each pixel showing the underwater detection result 22a projected onto a plane parallel to the horizontal plane, from the level of the received signal in the azimuth direction stored in the received signal array 15a.

[0104] Here, the direction θ and distance R, which are polar coordinates corresponding to the coordinate (X, Y), are not necessarily natural numbers used as indices in the received signal array 15a, but are almost always expressed as decimals. In this case, the level of the received signal at the coordinate (R, θ) is determined by taking a weighted average of the levels of the received signals of the four elements of the received signal array 15a that are close to the coordinate (R, θ) expressed as decimals. The weighted average is calculated so that the level of the received signal of the element of the received signal array 15a that is closest to the coordinate (R, θ) is given greater weight among the four elements.

[0105] For example, the level of the received signal at the coordinate (R, θ) = (49.8, 2.3) is calculated by taking a weighted average of the levels of the received signals of the elements of the received signal array 15a, which are indicated by the respective indices (R, θ) = (49, 2), (49, 3), (50, 2), and (50, 3).

[0106] Furthermore, the level of the received signal at the coordinate (R, θ) = (19.2, 6.7) is calculated by taking a weighted average of the levels of the received signals of the elements of the received signal array 15a, which are indicated by the respective indices (R, θ) = (19, 6), (19, 1), (20, 6), and (20, 1). The reason why the index "1" is used for direction θ is that the direction next to the direction indicated by direction θ "6" is the direction indicated by direction θ "1" in a clockwise direction.

[0107] Meanwhile, the vertical detection result image generation means 16b generates the vertical detection result 22b from the horizontal detection result image 22. The vertical detection result image generation means 16b identifies the level of the received signal at the position of the coordinate (X, Y) of the coordinate (X, Y) that indicates the position of each pixel in the region (for example, the region corresponding to the rear side of the ship 71) in which the vertical detection result 22b is displayed in place of the underwater detection result 22a projected onto a plane parallel to the horizontal plane (for example, the region corresponding to the rear side of the ship 71) from the element of the received signal array 15a with direction θ of "7".

[0108] At this time, the vertical detection result image generation means 16b generates the vertical detection result 22b in such a way that the distance in the distance direction of the underwater detection result 22a projected onto a plane parallel to the horizontal plane corresponds to the distance in the distance direction of the vertical detection result 22b in the horizontal detection result image 22. As a result, as described above, the depth of the underwater detection result 22a projected onto a plane parallel to the horizontal plane can be grasped more intuitively from the depth, which is the distance in the distance direction of the vertical detection result 22b.

[0109] Furthermore, the vertical detection result image generation means 16b generates vertical detection results 22b such that the stronger the level of the received signal of the reflected wave from distance R (depth), the longer the vertical detection result 22b is displayed in the azimuth direction, which is perpendicular to the distance direction, at the position corresponding to that distance R. This makes it possible to clearly communicate to the user the depth at which there was a strong reaction in the vertical direction. It also makes it easier for the user to visualize the presence of large fish or a school of fish formed by many fish at that location.

[0110] The detection result image generation means 16, in the area where the vertical detection result 22b, whose received signal level has been identified by the vertical detection result image generation means 16b is displayed, replaces the received signal level of the underwater detection result 22a projected onto a plane parallel to the horizontal plane, with the received signal level of the vertical detection result 22b. Then, the detection result image generation means 16 assigns a color to each pixel of the horizontal detection result image 22 according to the received signal level of that pixel. In this way, the detection result image generation means 16 can generate the horizontal detection result image 22.

[0111] The display control means 18 controls the display device 21 to display the horizontal detection result image 22 and other images generated by the detection result image generation means 16. For example, the display control means 18 adjusts the size and display position of the horizontal detection result image 22 and other detection result images, and also combines characters, symbols, figures, etc., with the horizontal detection result image 22, etc., to display a single image on the display device 21.

[0112] Next, a method for performing horizontal detection using the sonar function with the ultrasonic sonar device 1 of this embodiment, configured as described above, will be explained, mainly with reference to Figure 6.

[0113] When the user turns on the power to the ultrasonic sonar device 1 via the operation button 31, or when the user is instructed to start horizontal detection using the sonar function while the power is on, the ultrasonic sonar device 1 first drives the lifting device 41 to bring the transmitting and receiving unit 50 out of the water from the bottom of the ship 71. In the case of an ultrasonic sonar device 1 that does not have a lifting device 41 and in which the transmitting and receiving unit 50 is fixed to the ship 71 in a position where ultrasonic TB can be sent and received toward the water, the operation of driving the lifting device 41 is omitted.

[0114] Next, the ultrasonic sonar device 1 outputs drive signals from the transmitting unit 11a and the transmitting unit 11b, and transmits ultrasonic TBs from the first transducers 52a to 52f and the second transducer 53 of the transmitting and receiving unit 50 in the directions of the first central axis C1a to C1f and the second central axis C2, respectively. Due to the directional characteristics of the ultrasonic TBs transmitted from each of the first central axes C1a to C1f, ultrasonic TBs are transmitted to the ship 71 in all directions.

[0115] The ultrasonic TB transmitted from the first transducers 52a to 52f and the second transducer 53 is reflected from the detection target object GF, seabed SB, etc., that are present in a predetermined range from which the ultrasonic TB is transmitted. The reflected waves are received by the first transducers 52a to 52f and the second transducer 53, and signals (voltages) are output from the first transducers 52a to 52f and the second transducer 53 as the intensity of the reflected waves received in each direction of the first central axis C1a to C1f and the second central axis C2, respectively.

[0116] The signals (voltages) output from the first transducers 52a to 52f and the second transducer 53 are amplified by corresponding receiving units 13a to 13g at predetermined time intervals after the transmission of the ultrasonic TB, then sampled by converting them into digital signals (digital values), and output as received signals (original received signals) in each direction of the first central axis C1a to C1f and the second central axis C2.

[0117] These original received signals are subjected to spatial (and temporal) filtering by filter 14. Furthermore, filter 14 may set a virtual direction for each of the first central axes C1a to C1f at an intermediate position between adjacent first central axes C1a to C1f, and generate received signals from the received signals of the first transducers 52a to 52f, assuming that ultrasonic TB was virtually transmitted and received in that virtual direction.

[0118] The levels of the received signals in each direction of the first central axis C1a to C1f and the second central axis C2, after filtering by the filter 14, are stored by the storage means 15 in each element of the received signal array 15a shown in Figure 7. If the levels of virtual received signals in a virtually set virtual direction are also output, the levels of those virtual received signals are also stored in each element of the received signal array 15a.

[0119] Then, based on the level of the received signals in the direction of the first central axis C1a to C1f (the direction set as the azimuth direction) stored in the received signal array 15a, the horizontal detection result image generation means 16a generates the underwater detection result 22a projected onto a plane parallel to the horizontal plane. Also, based on the level of the received signals in the direction of the second central axis C2 (vertical direction) stored in the received signal array 15a, the vertical detection result image generation means 16b generates the vertical detection result 22b. Subsequently, the detection result image generation means 16 generates a horizontal detection result image 22 (see Figure 5) showing the underwater detection result 22a projected onto a plane parallel to the horizontal plane, and in a part of the underwater detection result 22a projected onto the plane parallel to the horizontal plane, the vertical detection result 22b is shown in place of the underwater detection result 22a projected onto the plane parallel to the horizontal plane. This horizontal detection result image 22 is then displayed on the display device 21 by the display control means 18.

[0120] As described above, according to the ultrasonic sonar device 1 of the first embodiment, when performing horizontal detection using the sonar function, the transmitting and receiving unit 50 attached to the ship 71 transmits ultrasonic TB into the water over a predetermined range, and reflected waves of ultrasonic TB reflected from each position in the water are received for each of the multiple directions set in the azimuth direction (directions of the first central axis C1a to C1f) and the vertical direction (direction of the second central axis C2). Based on the reflected waves received by the transmitting and receiving unit 50, a received signal is generated by the receiving units 13a to 13g and the filter 14 for each of the directions of the first central axis C1a to C1f and the second central axis C2. From the received signals for each direction of the generated first central axis C1a to C1f and second central axis C2, the detection result image generation means 16 generates a horizontal detection result image 22, which includes the underwater detection result 22a projected onto a plane parallel to the horizontal plane, based on the received signals in at least the direction of the first central axis C1a to C1f set in the azimuth direction. The horizontal detection result image 22 is then displayed by the display means. The user can determine the presence or absence of the object GF, as well as the direction and horizontal distance of the object GF, from the underwater detection result 22a projected onto a plane parallel to the horizontal plane shown in the horizontal detection result image 22.

[0121] Here, in the horizontal detection result image 22, the detection result image generation means 16 generates the horizontal detection result image 22 such that, in a certain directional region of the underwater detection result 22a projected onto a plane parallel to the horizontal plane, the vertical detection result 22b based on the received signal generated by the receiving unit 13g and filter 14 in the vertical direction is shown instead of the underwater detection result 22a projected onto a plane parallel to the horizontal plane. This allows the user to intuitively visualize the depth based on the vertical detection result 22b shown in a certain directional region of the underwater detection result 22a projected onto a plane parallel to the horizontal plane shown in the horizontal detection result image 22. Thus, the depth of the object GF being detected in horizontal detection can be intuitively grasped.

[0122] Furthermore, the detection result image generation means 16 generates a horizontal detection result image 22 so that the distance in the distance direction of the underwater detection result 22a projected onto a plane parallel to the horizontal plane corresponds to the distance in the distance direction of the vertical detection result 22b. Here, the distance in the distance direction of the vertical detection result 22b is the depth. Therefore, the depth of the underwater detection result 22a projected onto a plane parallel to the horizontal plane can be grasped more intuitively from the distance in the distance direction of the vertical detection result 22b.

[0123] (Second Embodiment) Next, an ultrasonic sonar device 1 according to a second embodiment of the present invention will be described with reference to Figures 8 to 10. Figure 8 is a block diagram showing the electrical configuration of the ultrasonic sonar device 1 according to the second embodiment. Figure 9 is a schematic diagram showing the contents of the received signal array 15b stored in the storage means 15 of the ultrasonic sonar device 1 according to the second embodiment. Figure 10 is a schematic diagram showing the conversion table 16c of the detection result image generation means 16 of the ultrasonic sonar device 1 according to the second embodiment.

[0124] In the first embodiment, when performing horizontal detection using the sonar function, the ultrasonic sonar device 1 separately generates the underwater detection result 22a projected onto a plane parallel to the horizontal plane and the vertical detection result 22b, and then generates a horizontal detection result image 22 such that the vertical detection result 22b is shown instead of the underwater detection result 22a projected onto the plane parallel to the horizontal plane in a certain azimuth region. In contrast, the ultrasonic sonar device 1 in the second embodiment generates a horizontal detection result image 22 including the underwater detection result 22a projected onto a plane parallel to the horizontal plane and the vertical detection result 22b in a single coordinate transformation process using a single transformation table 16c (see Figure 10).

[0125] The following description focuses on the differences between the ultrasonic sonar device 1 according to the second embodiment and the ultrasonic sonar device 1 according to the first embodiment. Components identical to those in the ultrasonic sonar device 1 according to the first embodiment are denoted by the same reference numerals, and their descriptions are omitted or simplified.

[0126] The differences between the ultrasonic sonar device 1 according to the second embodiment and the ultrasonic sonar device 1 according to the first embodiment are that the storage means 15 stores the received signal array 15b shown in Figure 9 instead of the received signal array 15a (see Figure 7), and the detection result image generation means 16 has a conversion table 16c instead of the horizontal detection result image generation means 16a and the vertical detection result image generation means 16b.

[0127] The received signal array 15b is the same as the received signal array 15a in the first embodiment in that it stores the received signals of the first oscillators 52a to 52f and the second oscillator 53, respectively (i.e., in the directions of the first central axes C1a to C1f and the second central axis C2), after filtering by the filter 14.

[0128] However, the received signal array 15b is provided with indices "1" to "9" for direction θ. Of these, in direction θ, "1" to "6" store the received signals from the first oscillators 52a to 52f, that is, the received signals in the direction of the first central axes C1a to C1f, which are set multiple times in the azimuthal direction, similar to the received signal array 15a. On the other hand, as shown in Figure 9, the received signal array 15b stores the received signal from the second oscillator 53, that is, the received signal in the direction of the second central axis C2, which is the vertical direction, in the element with direction θ "8" rather than the element with direction θ "7". In addition, the received signal array 15b is provided with elements with direction θ "7" and "9" as virtual directions, and for these directions θ, a predetermined value CL is pre-stored as the level of the virtual received signal in all distance R ("1" to "100") elements. The predetermined value CL is set to "0", a value that is negligible as a received signal level (for example, a value of "15" or less), or a received signal level value to which a color of approximately the same color as the background color is assigned in the horizontal detection result image 22. The predetermined value CL may be configured to be changeable by the user by operating the operation button 31.

[0129] It should be noted that the virtual directions indicated by the directions θ of "7" and "9" are different from the virtual directions set relative to the azimuth directions described in the first embodiment, and their technical significance is also different. The technical significance of the virtual directions indicated by the directions θ of "7" and "9" will be clarified in the following explanation.

[0130] As shown in Figure 8, the conversion table 16c provided in the detection result image generation means 16 associates the coordinates (X, Y) indicating the position of each pixel in the horizontal detection result image 22 with the coordinates (R, θ) in a polar coordinate system consisting of direction θ and distance R, which are indices of the received signal array 15b corresponding to those coordinates (X, Y). In this respect, it is the same as the conversion table described in the first embodiment. However, as shown in Figure 10, the conversion table 16c of the second embodiment is composed of a horizontal detection conversion table section 16c1 (the white cell portion in Figure 10) and a vertical detection conversion table section 16c2 (the gray cell portion in Figure 10).

[0131] The horizontal detection conversion table section 16c1 associates the coordinates (X,Y) of each pixel in the region showing the underwater detection result 22a projected onto a plane parallel to the horizontal plane in the horizontal detection result image 22 with the corresponding polar coordinate system coordinates (R,θ), which consist of the direction θ and distance R, which are indices of the received signal array 15b. Note that there are locations where null data is associated with the polar coordinate system coordinates (R,θ) instead of the coordinates (X,Y). This means that the coordinates (X,Y) in question are outside the circular region of the horizontal detection result image 22.

[0132] In the horizontal detection conversion table section 16c1, the corresponding direction θ is 1 ≤ θ < 7. Here, the direction indicated by 6 ≤ θ < 7 means the direction included from the direction θ indicated by "6" (direction of the first central axis C1c) to the direction θ indicated by "1" (direction of the first central axis C1b).

[0133] On the other hand, the vertical detection conversion table section 16c2 associates the coordinates (X, Y) of each pixel included in the region showing the vertical detection result 22b of the horizontal detection result image 22 (for example, the region corresponding to the rear side of the ship 71) with the coordinates (R, θ) of a polar coordinate system consisting of direction θ and distance R, which are indices of the received signal array 15b that correspond to those coordinates (X, Y).

[0134] In the vertical detection conversion table section 16c2, the direction θ to be associated is 7 ≤ θ ≤ 9. Specifically, for the coordinates (X, Y) of each pixel located in the center of the area showing the vertical detection result 22b, the direction θ is associated with "8.00". As a result, each pixel located in the center of the area showing the vertical detection result 22b is assigned the level of the received signal in the vertical direction (direction of the second central axis C2), which is stored in the element with direction θ of "8" in the received signal array 15b. Therefore, the level of the received signal in the vertical direction (direction of the second central axis C2) is shown for each pixel located in the center of the area showing the vertical detection result 22b.

[0135] On the other hand, in the vertical detection conversion table section 16c2, for the coordinates (X, Y) of each pixel located far from the center of the region showing the vertical detection result 22b, the greater the distance from the center, the more a decimal value closer to "7" or "9" is associated with the direction θ. In other words, the vertical detection conversion table section 16c2 associates the coordinates (X, Y) of each pixel included in the region showing the vertical detection result 22b in the horizontal detection result image 22 with a direction θ of "8" (the vertical direction), or a direction between the vertical direction and a virtual direction, represented by a decimal value in the range of "7" to "9" excluding "8" (the vertical direction).

[0136] Furthermore, the vertical detection conversion table section 16c2 is configured such that, within the horizontal detection result image 22, the distance in the distance direction of the underwater detection result 22a projected onto a plane parallel to the horizontal plane (the direction of radiation of ultrasonic waves TB from the first transducer 52, i.e., the direction along the first central axis C1a to C1f) corresponds to the distance in the vertical detection result 22b (the direction of radiation of ultrasonic waves TB from the second transducer 53, i.e., the direction along the second central axis C2). Specifically, the vertical detection conversion table section 16c2 is configured such that the depth of the detection result represented at each position in the distance direction of the vertical detection result 22b matches the depth of the detection result represented at each position in the distance direction of the underwater detection result 22a projected onto a plane parallel to the horizontal plane.

[0137] In the ultrasonic sonar device 1 configured as described above, the following operation occurs: The detection result image generation means 16 uses a conversion table 16c to identify the polar coordinate system coordinates (R, θ) corresponding to the coordinates (X, Y) of each pixel. Then, for each pixel, the detection result image generation means 16 identifies the level of the received signal at the location of the identified coordinates (R, θ) from the received signal array 15b stored in the storage means 15, and sets the identified level of the received signal as the level of the received signal for that pixel.

[0138] Here, the conversion table 16c is composed of a horizontal detection conversion table section 16c1 corresponding to the region showing the underwater detection result 22a projected onto a plane parallel to the horizontal plane in the horizontal detection result image 22, and a vertical detection conversion table section 16c2 corresponding to the region showing the vertical detection result 22b in the horizontal detection result image 22. By using one such conversion table 16c, the detection result image generation means 16 can generate a horizontal detection result image 22 having the underwater detection result 22a projected onto a plane parallel to the horizontal plane and the vertical detection result 22b in a single image conversion process.

[0139] Furthermore, in the conversion table 16c, the direction θ and distance R, which are polar coordinate coordinates corresponding to the coordinates (X, Y), are expressed as decimal numbers. In this case, even in the second embodiment, the detection result image generation means 16 determines the level of the received signal at the coordinate (R, θ) by weighting the levels of the received signals of four elements that are close to the position of the coordinate (R, θ) expressed as a decimal number. The weighted average is calculated so that the level of the received signal of the element of the received signal array 15a that is closest to the position of coordinate (R, θ) is reflected more strongly among the four elements.

[0140] On the other hand, as described above, in the vertical detection conversion table section 16c2 of the conversion table 16c, for the coordinates (X, Y) of each pixel located far from the center of the region showing the vertical detection result 22b, the greater the distance from the center, the closer the direction θ is to a decimal value of "7" or "9". As a result, the detection result image generation means 16 can determine the level of the received signal in the region of the vertical detection result 22b according to the vertical detection conversion table section 16c2 described above, and propagate the strong intensity of the received signal in the azimuth direction, which is perpendicular to the distance direction (vertical direction), where the intensity of the received signal is strong in the vertical direction. Therefore, the depth at which there was a strong reaction in the vertical direction can be clearly conveyed to the user from the vertical detection result 22b. Furthermore, it can be made easier for the user to imagine that there is a large fish or a school of fish formed by many fish at that location. This is the technical significance of introducing the virtual direction indicated by the direction θ of "7" and "9".

[0141] Furthermore, as described above, the vertical detection conversion table unit 16c2 associates the coordinates (X, Y) of each pixel with the coordinates (R, θ) of the polar coordinate system, so that in the horizontal detection result image 22, the distance in the distance direction of the underwater detection result 22a projected onto a plane parallel to the horizontal plane corresponds to the distance in the distance direction of the vertical detection result 22b. As a result, the horizontal detection result image 22 generated by the detection result image generation means 16 associates the distance in the distance direction of the underwater detection result 22a projected onto a plane parallel to the horizontal plane with the distance in the distance direction of the vertical detection result 22b. Therefore, the depth in the underwater detection result 22a projected onto a plane parallel to the horizontal plane can be intuitively grasped from the depth, which is the distance in the distance direction of the vertical detection result 22b.

[0142] In particular, the vertical detection conversion table unit 16c2 associates the coordinates (X, Y) of each pixel with the coordinates (R, θ) of the polar coordinate system so that the depth of the detection result, mainly represented at each position in the distance direction of the underwater detection result 22a projected onto a plane parallel to the horizontal plane, and the depth of the detection result, represented at each position in the distance direction of the vertical detection result 22b, coincide. This allows for a more accurate determination of the depth in the underwater detection result 22a projected onto a plane parallel to the horizontal plane from the depth, which is the distance in the distance direction of the vertical detection result 22b.

[0143] Furthermore, the vertical detection conversion table section 16c2 may associate the coordinates (X, Y) of each pixel with the coordinates (R, θ) of the polar coordinate system, such that in the horizontal detection result image 22, the slant distance at each position in the distance direction of the underwater detection result 22a projected onto a plane parallel to the horizontal plane matches the distance (depth) in the distance direction of the vertical detection result 22b. In this case, the depth of the detection result mainly represented at each position in the distance direction of the underwater detection result 22a projected onto a plane parallel to the horizontal plane and the depth of the detection result represented at each position in the distance direction of the vertical detection result 22b will not exactly match, but it will be possible to give the user an intuitive image of the depth in the underwater detection result 22a projected onto a plane parallel to the horizontal plane.

[0144] As described above, the ultrasonic sonar device 1 according to the second embodiment provides the following effects in addition to the effects of the ultrasonic sonar device 1 according to the first embodiment.

[0145] Specifically, the storage means 15 stores the received signals generated by the receiving units 13a to 13g and the filter 14 in a received signal array 15b for each direction of the first central axis C1a to C1f and the second central axis C2. The received signals are indexed by their direction θ and the distance R at which the reflected ultrasonic TB, which is the basis of the received signal, was generated. A conversion table 16c is provided in the detection result image generation means 16, which shows the direction θ and distance R of the received signal array 15b corresponding to the coordinates (X, Y) of each position in the horizontal detection result image 22. Based on the conversion table 16c, the level of the received signal at the coordinates (X, Y) of each position in the horizontal detection result image 22 is identified from the received signal array 15b, and the detection result image generation means 16 generates the horizontal detection result image 22.

[0146] Here, in the conversion table 16c, each coordinate (X, Y) included in the region of the horizontal detection result image 22 that shows the underwater detection result 22a projected onto a plane parallel to the horizontal plane is associated with the direction θ (1 ≤ θ < 7) set in the azimuth direction of the received signal array 15b, and each coordinate (X, Y) included in the region of the horizontal detection result image 22 that shows the vertical detection result 22b is associated with the vertical direction (7 ≤ θ ≤ 9). As a result, the detection result image generation means 16 can generate the horizontal detection result image 22 based on the conversion table 16c without considering the region showing the underwater detection result 22a projected onto a plane parallel to the horizontal plane and the region showing the vertical detection result 22b, and can easily generate a horizontal detection result image 22 that includes the region showing the underwater detection result 22a projected onto a plane parallel to the horizontal plane and the region showing the vertical detection result 22b with only one coordinate transformation process. Therefore, the horizontal detection result image 22 can be generated efficiently.

[0147] Furthermore, a virtual direction θ (θ=7,9) is provided for all distances in the distance direction, to which a predetermined value CL is shown as the virtual received signal level. In the conversion table 16c, each coordinate (X,Y) included in the region showing the vertical detection result 22b of the horizontal detection result image 22 is associated with the vertical direction (θ=8) or a direction between the vertical direction and the virtual direction (7≦θ<8, 8<θ≦9). The detection result image generation means 16 then determines the received signal level by weighting the received signal level in the vertical direction (θ=8) and the predetermined value CL in the virtual direction (θ=7,9) based on the respective distances from the vertical direction (θ=8) and the virtual direction (θ=7,9) for the coordinates (X,Y) associated with the direction between the vertical direction and the virtual direction (7≦θ<8, 8<θ≦9) in the conversion table 16c. As a result, the detection result image generation means 16 can display the detection result with a long length in the azimuth direction, which is perpendicular to the distance direction, where the level (intensity) of the received signal is strong in the vertical direction (direction of the second central axis C2), simply by identifying the level of the received signal according to the conversion table 16c. Therefore, while improving processing efficiency, the depth at which there was a strong reaction in the vertical direction (direction of the second central axis C2) can be conveyed to the user in a more understandable way.

[0148] Although the present invention has been described above based on embodiments, it is easy to infer that the present invention is not limited in any way to the above embodiments, and that various improvements and modifications are possible without departing from the spirit of the present invention. For example, each embodiment may be modified by adding or replacing some or more parts of the configuration of other embodiments with parts or more parts of the configuration of other embodiments, including the modifications described below. Furthermore, the numerical values ​​given in the above embodiments are merely examples, and it is naturally possible to use other numerical values.

[0149] In the second embodiment described above, a case was described in which the received signal array 15b is provided with an element for a virtual direction θ (θ = 7, 9) in which a predetermined value CL is shown as the level of a virtual received signal for all distances in the distance direction. However, it is not necessary for the received signal array 15b to be provided with an element for that virtual direction θ (θ = 7, 9). For example, a predetermined value CL to be applied to all distances R in the virtual direction θ may be stored in a flash memory or ROM provided in the control device 10. In this case, if a coordinate (X, Y) included in the region showing the detection result 22b in the vertical direction is associated with a direction between the vertical direction and the virtual direction (7 ≤ θ < 8, 8 < θ ≤ 9), then the predetermined value CL, which is the level of the received signal in the virtual direction, should be read from the flash memory or ROM.

[0150] Furthermore, among the virtual directions θ (θ = 7, 9) for which a predetermined value CL is shown as the level of a virtual received signal for all distances in the distance direction, only the element for one of the virtual directions may be provided in the received signal array 15b. For example, if the received signal array 15b only provides the element for the virtual direction θ = "7", and in the conversion table 16c a decimal number 8 < θ ≤ 9 is associated with one coordinate (X, Y) as the direction θ between the vertical direction and the virtual direction, then the element for the virtual direction θ = 7 may be read from the received signal array 15b instead of the element for the virtual direction θ = 9.

[0151] In the above embodiment, the case in which the first transducers 52a to 52f are inclined to face inward (towards the side where the second transducer 53 is located) has been described. However, the invention is not limited to this, and the first transducers 52a to 52f may also be inclined to face outward (towards the side opposite to the side where the second transducer 53 is located) with respect to each other. In this case as well, it is preferable that the first central axes C1a to C1f each form a predetermined angle ω with respect to the second central axis C2 (the vertical direction when the transmitting / receiving unit 50 is attached to the ship 71), selected from a range of 20° to 50°.

[0152] In the above embodiment, the case in which the first transducers 52a to 52f are provided around the second transducer 53 in the transmitting and receiving unit 50 was described. However, the arrangement of the first transducers 52a to 52f and the second transducer 53 in the transmitting and receiving unit 50 can be arbitrary, as long as, when the transmitting and receiving unit 50 is attached to the ship 71, the second central axis C2 is in the vertical direction, the first central axes C1a to C1f form a predetermined angle ω with respect to the second central axis C2 (in other words, the vertical direction), and the first central axes C1a to C1f are in a predetermined direction. For example, the first oscillators 52a to 52f and the second oscillator 53 may be arranged in one or two rows, or the first oscillators 52a to 52f may be arranged in two rows and the second oscillator 53 may be placed at any position between the two rows of the first oscillators 52a to 52f.

[0153] In the above embodiment, the case in which detection is performed over a predetermined range set in all directions of the vessel 71 was described. However, the predetermined range may be a predetermined range set for a part of the directions of the vessel 71.

[0154] In the above embodiment, the number of first transducers 52 in the transmitting / receiving unit 50 is reduced, and the ultrasonic TB is transmitted and received simultaneously from the first transducers 52 over a predetermined range set in all directions of the ship 71 to perform horizontal detection. However, the present invention generates a horizontal detection result image 22 such that the detection result image generation means 16 shows vertical detection results 22b based on the received signal of reflected ultrasonic TB reflected from the vertical direction in a certain azimuth region of the horizontal detection result image 22, rather than underwater detection results 22a projected onto a plane parallel to the horizontal plane. This invention is also applicable to detection using PPI sonar and scanning sonar.

[0155] 1. Ultrasonic sonar device 11a. Transmitting unit 11b. Transmitting unit 13a. Receiving unit 13b. Receiving unit 13c. Receiving unit 13d. Receiving unit 13e. Receiving unit 13f. Receiving unit 13g. Receiving unit 14. Filter 15. Storage means 15a. Received signal array 15b. Received signal array 16. Detection result image generation means 16a. Horizontal detection result image generation means 16b. Vertical detection result image generation means 16c. Conversion table 16c1. Conversion table section for horizontal detection 16c2. Conversion table section for vertical detection 18. Display control means 21. Display device 22. Horizontal detection result image 22a. Underwater detection result 22b. Vertical detection result 50. Transmitting / receiving unit 52. First transducer 52a. First transducer 52b. First transducer 52c. First transducer 52d First transducer 52e First transducer 52f First transducer 53 Second transducer 71 Ship C1 First central axis C1a First central axis C1b First central axis C1c First central axis C1d First central axis C1e First central axis C1f First central axis C2 Second central axis GF Detected object TB Ultrasound

Claims

1. An ultrasonic sonar device comprising: a transmitter / receiver unit mounted on a ship and capable of transmitting ultrasonic waves into the water over a predetermined range and receiving reflected ultrasonic waves reflected from each position in the water for each predetermined direction including at least a plurality of directions set in the azimuthal direction and the vertical direction; a receiving signal generation means that generates a received signal for each predetermined direction based on the reflected waves received by the transmitter / receiver unit; a detection result image generation means that generates a detection result image showing the underwater detection result projected onto a plane parallel to the horizontal plane based on the received signals generated by the receiving signal generation means in at least the directions set in the azimuthal direction; and a display means that displays the detection result image generated by the detection result image generation means, wherein the detection result image generation means generates the detection result image such that a portion of the azimuthal region of the detection result image shows the vertical detection result based on the received signals generated by the receiving signal generation means in the vertical direction, rather than the underwater detection result projected onto a plane parallel to the horizontal plane.

2. The ultrasonic sonar device according to claim 1, characterized in that the detection result image generation means generates the detection result image such that the distance in the distance direction of the detection result in the water projected onto a plane parallel to the horizontal plane corresponds to the distance in the distance direction of the detection result in the vertical direction.

3. The ultrasonic sonar device according to claim 1, characterized in that the detection result image generation means generates the detection result image such that, in the vertical detection result, the stronger the intensity of the received signal, the longer it is displayed in the direction perpendicular to the distance direction.

4. The ultrasonic sonar device according to claim 1, characterized in that the detection result image generation means generates the detection result image such that the vertical detection result is shown in the region corresponding to the rear side of the vessel in the detection result image.

5. The ultrasonic sonar device according to any one of claims 1 to 4, comprising a storage means for storing the received signals generated by the receiving signal generation means for each predetermined direction in a received signal array indexed by the direction and the distance at which the reflected ultrasonic wave that forms the basis of the received signal was generated, wherein the detection result image generation means has a conversion table showing the direction and distance of the received signal array corresponding to each coordinate of the detection result image, and generates the detection result image after identifying the level of the received signal at each coordinate of the detection result image from the received signal array based on the conversion table, wherein the conversion table associates each coordinate included in the region showing the underwater detection result projected onto a plane parallel to the horizontal plane with the direction set in the azimuth direction of the received signal array, and associates each coordinate included in the region showing the vertical detection result in the detection result image with the vertical direction.

6. A virtual direction is provided in which a predetermined value is shown as the level of a virtual received signal for all distances in the distance direction; the conversion table associates the vertical direction or the direction between the vertical direction and the virtual direction with each coordinate included in the region showing the detection result in the vertical direction of the detection result image; and the detection result image generation means determines the level of the received signal at the coordinate by weighting the level of the received signal in the vertical direction and the predetermined value of the virtual direction based on the distances from the vertical direction and the virtual direction, respectively, for the coordinates to which the direction between the vertical direction and the virtual direction is associated in the conversion table, as described in claim 5.

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