Ultrasonic sonar device

Abstract

This ultrasonic sonar device is provided with: a wave transmission / reception unit capable of transmitting an ultrasonic wave over a predetermined range in water and receiving, for each predetermined direction, a reflected wave of the ultrasonic wave reflected from each position in the water; and a detection result image generation means for generating a detection result image indicating the latest detection result over the predetermined range. Each of a plurality of first oscillators provided in the wave transmission / reception unit is fixed such that the center axis thereof is in the predetermined direction, and has a predetermined directional characteristic so as to include at least the center axis of the adjacent first oscillator and a vertical direction. A high-pass filter is applied to an azimuth direction (S11-S17) and a low-pass filter is applied to a distance direction (S18) with respect to the intensity of the reflected wave obtained for each of the first oscillators, and then a reception signal for each predetermined direction is generated.

Description

Ultrasonic sonar device

[0001] The present invention relates to an ultrasonic sonar device that is mounted on a ship and performs underwater detection over a predetermined range around the ship.

[0002] Ultrasonic sonar devices are known that use the transmission and reception of ultrasonic waves to detect objects such as schools of fish over a predetermined range in the water. While general fish finders detect objects in a vertical direction from the ship, ultrasonic sonar devices can detect objects in the vicinity of the ship, such as horizontally and vertically. Examples of ultrasonic sonar devices include PPI sonar (searchlight sonar) and scanning sonar.

[0003] PPI sonar emits (transmits) a narrow beam of ultrasonic waves, and a transducer that receives the reflected waves from the object to be detected is configured to rotate or rotatably, allowing for underwater detection around a ship while changing the direction of ultrasonic wave emission (for example, Patent Document 1). Because the transducer structure is simple, it can be manufactured inexpensively, but it takes time to complete a single detection over a predetermined range.

[0004] Scanning sonar works by forming an array of multiple tiny transducers on the surface of a cylindrical or spherical object, simultaneously transmitting ultrasonic waves from each transducer, and receiving the reflected waves to detect the underwater environment around a ship (for example, Patent Document 2). While it allows for a single detection over a predetermined range in a short time, the transducer array becomes complex, and the transmitting and receiving circuits for each transducer to send and receive ultrasonic waves become large, making it expensive.

[0005] Japanese Patent Publication No. 2019-066208 Japanese Patent Publication No. 2019-200204

[0006] In contrast to conventional ultrasonic sonar devices, the inventor has invented an ultrasonic sonar device that enables high-speed detection at low cost by simultaneously transmitting ultrasonic waves over a predetermined range using a small number of transducers and receiving the reflected waves, with the aim of further popularizing ultrasonic sonar devices. However, further improvements are needed before this device can be introduced to the market as a product.

[0007] This invention has been made in view of the above circumstances, and aims to provide an ultrasonic sonar device that can achieve high-speed detection at low cost and can harmonize resolution in the azimuth and distance directions.

[0008] To achieve this objective, a first aspect of the present invention comprises: a transmitting and receiving unit capable of transmitting ultrasonic waves over a predetermined range in water and receiving reflected ultrasonic waves reflected from each position in the water in a predetermined direction; a receiving signal generation means that generates a received signal for each predetermined direction based on the reflected waves received by the transmitting and receiving unit; and a detection result image generation means that generates a detection result image showing the latest detection result over the predetermined range based on the received signals for each predetermined direction generated by the receiving signal generation means, wherein the transmitting and receiving unit comprises a plurality of first transducers having predetermined directional characteristics with respect to the central axis, and the plurality Each of the first transducers is fixed such that its central axis is in the predetermined direction and, when the transmitting / receiving unit is attached to a ship, its central axis is at a predetermined angle with respect to the vertical direction, and has predetermined directional characteristics that include at least the central axis of an adjacent first transducer and the vertical direction. The receiving signal generation means applies a high-pass filter in the azimuth direction and a low-pass filter in the distance direction to the intensity of the reflected wave obtained for each of the plurality of first transducers by each of the first transducers receiving the reflected wave, and then generates the receiving signal for each predetermined direction.

[0009] A second aspect of the present invention is an ultrasonic sonar device according to the first aspect, wherein the receiving signal generating means applies a filter capable of maintaining the total energy of the received reflected waves to the receiving signal for each predetermined direction, thereby generating a receiving signal that assumes that ultrasonic waves were virtually transmitted and received in a virtual direction set between the predetermined directions.

[0010] A third aspect of the present invention is an ultrasonic sonar device according to the second aspect, wherein the detection result image generation means generates the detection result image in a manner that allows determination of the predetermined direction and the virtual direction.

[0011] A fourth aspect of the present invention is an ultrasonic sonar device according to the third aspect, wherein the detection result image generation means generates the detection result image such that a first line is represented in a first aspect with respect to the predetermined direction, and a second line is represented in a second aspect different from the first aspect with respect to the virtual direction.

[0012] A fifth aspect of the present invention is an ultrasonic sonar device according to the second aspect, wherein the detection result image generation means generates the detection result image in such a way that the reliability of the received signals generated in each direction can be determined.

[0013] According to the ultrasonic sonar device of the first aspect of the present invention, ultrasonic waves are transmitted over a predetermined range in the water by a transmitting / receiving unit. Reflected ultrasonic waves reflected from each position in the water in each predetermined direction are received by the transmitting / receiving unit. Based on the reflected waves received by the transmitting / receiving unit, a received signal is generated by a received signal generation means for each predetermined direction. Based on the generated received signals for each predetermined direction, a detection result image showing the latest detection results over the predetermined range is generated by a detection result image generation means. From this detection result image, it is possible to determine whether or not there is a target object in the predetermined range and the location where the target object is located.

[0014] Here, multiple first transducers are fixed to the transducer unit such that their central axes are oriented in a predetermined direction, and that when the transducer unit is mounted on a ship, their central axes are positioned at a predetermined angle to the vertical. Each first transducer has predetermined directional characteristics that include at least the central axis of an adjacent first transducer and the vertical direction. This allows for simultaneous transmission of ultrasonic waves over a predetermined range using a small number of first transducers, and detection of objects by receiving the reflected waves. Thus, high-speed detection can be achieved at low cost.

[0015] Furthermore, while transmitting and receiving ultrasound with a small number of first transducers may significantly reduce azimuthal resolution, the receiving signal generation means applies a high-pass filter in the azimuthal direction and a low-pass filter in the distance direction to the intensity of the reflected wave obtained for each of the multiple first transducers by receiving the reflected wave, thereby generating a received signal for each predetermined direction. This improves azimuthal resolution while suppressing distance resolution, thus achieving overall harmony between azimuthal and distance resolution. Therefore, it is possible to realize high-speed detection at low cost and achieve harmony between azimuthal and distance resolution.

[0016] 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, by applying a filter capable of maintaining the total energy of the received reflected waves to the received signal for each predetermined direction, the received signal generation means generates a received signal that assumes ultrasonic waves were virtually transmitted and received in a virtual direction set between the predetermined directions. As a result, the received signal in the virtual direction is inserted between the predetermined directions, which has the effect of improving the resolution in the azimuth direction. Furthermore, since the received signal in the virtual direction is generated in a way that maintains the total energy of the received reflected waves, it is possible to suppress the increase in the total energy in the image compared to the total energy of the received reflected waves when the received signal in the virtual direction is inserted. Therefore, by inserting the received signal in the virtual direction, it is possible to suppress the detection result image from showing a higher level of reaction than the actual detection result.

[0017] 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 second embodiment. Specifically, it is possible to determine a predetermined direction and a virtual direction in the detection result image generated by the detection result image generation means. This makes it possible to clearly indicate to the user the virtual direction in which the reliability of detection is lower than that of the predetermined direction in which ultrasonic waves were actually transmitted and received. As a result, the user can check the detection results while taking into account the reliability of detection in each direction.

[0018] The ultrasonic sonar device according to the fourth embodiment provides the following effects in addition to the effects of the ultrasonic sonar device according to the third embodiment. Specifically, the detection result image is generated by the detection result image generation means so that a first line is represented in a first manner for a predetermined direction, and a second line is represented in a second manner different from the first manner for a virtual direction. This has the effect that the user can determine at a glance from the detection result image whether the predetermined direction is a virtual direction or a virtual direction with lower detection reliability.

[0019] The ultrasonic sonar device according to the fifth embodiment provides the following effects in addition to those of the ultrasonic sonar device according to the second embodiment. Specifically, the reliability of the received signals generated in each direction can be determined from the detection result image generated by the detection result image generation means. This has the effect that, in a detection result image in which a predetermined direction with high detection reliability due to actual ultrasonic transmission and reception is mixed with a virtual direction with lower detection reliability, the user can easily grasp the reliability of detection within the detection result image and confirm the detection results.

[0020] It is a schematic diagram schematically showing the configuration of an ultrasonic sonar device which is an embodiment of the present invention. It is a schematic diagram showing from the side the state when detection in water is performed by a ship on which the ultrasonic sonar device is mounted. (a) is a schematic cross-sectional view showing a transmitting and receiving unit of the ultrasonic sonar device, and (b) is a schematic perspective view showing the arrangement modes of a plurality of first vibrators and second vibrators constituting the transmitting and receiving unit. (a) is a diagram schematically showing the first central axis of each of the first vibrators when viewed vertically from above the ship, (b) is a diagram schematically showing the first central axis when viewed horizontally from the front side of the ship, (c) is a diagram schematically showing the directivity characteristics of ultrasonic waves transmitted from the first vibrator, and (d) is a diagram showing the directivity characteristics of ultrasonic waves transmitted from the first vibrator as viewed from the front side of the ship. It is a block diagram showing the electrical configuration of the ultrasonic sonar device. It is a flowchart showing spatial filter processing. It is a diagram schematically showing an example of a display screen displayed on a display device of the ultrasonic sonar device.

[0021] Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings. Note that each of the embodiments described below shows a preferred specific example of the present invention. Therefore, numerical values, shapes, materials, components, arrangement positions of components, connection forms, etc. shown in the following embodiments are merely examples and are not intended to limit the present invention. Therefore, among the components in the following embodiments, components not described in the independent claims indicating the most general concept of the present invention are described as optional components. Also, in each figure, the same reference numerals are given to substantially the same configurations, and overlapping explanations are omitted or simplified.

[0022] First, referring to FIGS. 1 and 2, an ultrasonic sonar device 1 according to an embodiment of the present invention will be described. FIG. 1 is a schematic diagram schematically showing the configuration of the ultrasonic sonar device 1, and FIG. 2 is a schematic diagram showing from the side the state when detection in water is performed by a ship 71 on which the ultrasonic sonar device 1 is mounted.

[0023] As shown in FIGS. 1 and 2, the ultrasonic sonar device 1 is mounted on a ship 71, and has at least a sonar function for horizontally detecting a detection target object GF such as a fish school over a predetermined range around the ship 71 with respect to water such as the sea, lake, or river in which the ship 71 floats. Horizontal detection is to detect the detection target object GF included in the predetermined range with the entire range of directions as the predetermined range when viewed from the ship 71. The ultrasonic sonar device 1 may have a sonar function for performing vertical cross-sectional detection in addition to horizontal detection, or may have a fish school detection function for detecting a detection target object GF existing in the vertical direction directly below the ship 71 and arranging the detection results in time series for display.

[0024] The ultrasonic sonar device 1 includes a main body 5, an operation button 31 provided on the main body 5, a display device 21 integrally formed with the main body 5, a transmission / reception unit 50 for transmitting and receiving ultrasonic waves TB for detecting a detection target object GF, and a lifting device 41 for lifting and lowering the transmission / reception unit 50. The main body 5, the operation button 31, and the display device 21 are arranged in the steering room of the ship 71, and the transmission / reception unit 50 and the lifting device 41 are arranged in the bottom of the ship 71. The transmission / reception unit 50 can emerge and submerge with respect to the water from the bottom of the ship 71 by being lifted and lowered by the lifting device 41.

[0025] The operation button 31 is a button that can be operated by a user, and is operated when the user gives various instructions and settings to the ultrasonic sonar device 1. For example, turning on / off the power of the ultrasonic sonar device 1, setting the brightness of the image displayed on the display device 21, and instructing the start / end of horizontal detection by the sonar function are performed by the user via the operation of the operation button 31.

[0026] As shown in FIG. 2, the ultrasonic sonar device 1 transmits (irradiates) ultrasonic waves TB in a conical shape as a predetermined range from the transmission / reception unit 50 in a state where the transmission / reception unit 50 protrudes from the bottom of the ship 71. Then, the transmission / reception unit 50 is configured to be able to receive reflected waves of the ultrasonic waves TB reflected from a detection target object GF included in the conical predetermined range, the seabed or the lake bottom (hereinafter, these are collectively referred to as "water bottom SB"), etc. The detailed configuration of the transmission / reception unit 50 will be described later with reference to FIGS. 3 and 4.

[0027] 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), which will be 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 the detection result image 22, etc. Details of the detection result image 22 will be described later with reference to Figure 7.

[0028] 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.

[0029] 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.

[0030] As shown in Figure 3, the transmitting and receiving unit 50 has a structure in which multiple (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 second transducers 53, which transmit ultrasonic TB in a predetermined direction and receive the reflected waves, 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.

[0031] Each of the first transducer 52 and the second transducer 53 includes 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] On the other hand, in the transmitting and receiving unit 50, as shown in Figure 3, the first transducers 52a to 52f are arranged with their acoustic radiation surfaces tilted such that the first central axes C1a to C1f make a predetermined angle θ with respect to the second central axis C2 (i.e., the vertical direction when the transmitting and receiving unit 50 is attached to the ship 71). As a result, the acoustic radiation direction of each of the first transducers 52a to 52f is oriented in a direction different from the vertical direction directly below the ship 71, as shown in Figure 4(b).

[0042] In this embodiment, each of the first transducers 52a to 52f is inclined so that their acoustic radiating surfaces face inward (towards the side where the second transducer 53 is located) (see Figure 3). In this case, each of the first central axes C1a to C1f is preferably at a predetermined angle θ with respect to the second central axis C2, selected from a range of 20° to 50°. In this embodiment, the predetermined angle θ is 30°. As shown in Figure 3(a), each of the first central axes C1a to C1f and the second central axis C2 are converged at a single point.

[0043] Furthermore, the first central axes C1a to C1f of the first transducers 52a to 52f are arranged at equal intervals in the azimuthal direction, as shown in Figure 4(a), so that the angles between adjacent first central axes C1a to C1f are the same angle δ when viewed vertically from above the ship 71 with the transmitting and receiving unit 50 attached to the ship 71. When there are n first transducers 52, the angle δ is (360 / n)° (when there are 6 first transducers 52, the angle δ is 60°).

[0044] As a result, the transmitting and receiving unit 50 can simultaneously transmit ultrasonic waves TB in each predetermined direction indicated by the first central axis C1a to C1f, using at least the first transducers 52a to 52f, over a predetermined range set in all directions of the ship 71, and can also receive reflected waves in each of those predetermined directions.

[0045] In this embodiment, as shown in Figures 4(a) and (b), when viewing the ship 71 from above in a vertical direction, the first central axis C1a is oriented to the right with respect to the front-to-back direction of the ship 71, and the first central axes C1b to C1f are arranged in order counterclockwise from the first central axis C1a at intervals of angle δ. In this embodiment, an example is shown in which the first transducers 52a to 52f are arranged so that their respective first central axes C1a to C1f are evenly spaced in the azimuthal direction. However, it is sufficient that the ultrasonic TB can be transmitted simultaneously by at least the first transducers 52a to 52f in each predetermined direction indicated by the first central axes C1a to C1f over a predetermined range set in all directions of the ship 71, and there may be variations in the spacing of the first central axes C1a to C1f.

[0046] The directional characteristics of the ultrasonic TB transmitted from each of the first transducers 52a to 52f are set to include the first central axes C1a to C1f of adjacent first transducers 52. For example, as shown in Figure 4(c), the directional characteristics of the ultrasonic TB transmitted from the first transducer 52a are set to include the first central axis C1b of the adjacent first transducer 52b and the first central axis C1f of the first transducer 52f.

[0047] On the other hand, the directional characteristics of the ultrasonic TB transmitted from the first transducer 52b and the directional characteristics of the ultrasonic TB transmitted from the first transducer 52f are set to include the first central axis C1a of the first transducer 52a. Although not shown in the figures, the directional characteristics of the ultrasonic TB transmitted from the first transducer 52b are also set to include the first central axis C1c of the first transducer 52c adjacent on the opposite side from the first transducer 52a, and the directional characteristics of the ultrasonic TB transmitted from the first transducer 52f are also set to include the first central axis C1e of the first transducer 52e adjacent on the opposite side from the first transducer 52a.

[0048] Furthermore, the directional characteristics of the ultrasonic TB transmitted from each of the first transducers 52a to 52f are set to include the vertical direction when the transmitting and receiving unit 50 is attached to the ship 71, as shown in Figure 4(d).

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] Next, the electrical configuration of the ultrasonic sonar device 1 will be described with reference to Figure 5. Figure 5 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, detection result image generation means 15, and display control means 18.

[0054] Each of the transmitting units 11a, 11b, receiving units 13a to 13g, filter 14, detection result image generation means 15, and display control means 18 may be configured in hardware, implemented in software, or implemented through the cooperation of hardware and software.

[0055] 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.

[0056] Of the transmitting units 11a, 11b, receiving units 13a to 13g, filter 14, detection result image generation means 15, and display control means 18, the parts that are implemented by software or by the cooperation of hardware and software are implemented by the CPU executing a program.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] The transmitting unit 11b is one of the ultrasonic transmission driving means of the present invention and 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 makes it possible to suppress the backflow of the signal (voltage) output by the second transducer 53 when it receives the reflected wave of ultrasonic TB to the transmitting unit 11b.

[0063] 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.

[0064] 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.

[0065] Receiving units 13a to 13g are provided for each of the multiple (6) first transducers 52a to 52f and second transducer 53. The corresponding first transducers 52a to 52f and second transducer 53 receive the reflected waves of the ultrasonic TB, and the receiving units capture a signal (voltage) output according to the intensity of the reflected waves, and perform predetermined processing on the captured signal.

[0066] Specifically, receiving unit 13a is connected to the first oscillator 52a and performs predetermined processing on the signal (voltage) output according to the intensity of the reflected wave received by the first oscillator 52a. Similarly, receiving unit 13b is connected to the first oscillator 52b, receiving unit 13c is connected to the first oscillator 52c, receiving unit 13d is connected to the first oscillator 52d, receiving unit 13e is connected to the first oscillator 52e, receiving unit 13f is connected to the first oscillator 52f, and receiving unit 13g is connected to the second oscillator 53. Each receiving unit 13b to 13g also performs predetermined processing on the signal (voltage) output according to the intensity of the reflected wave received by the connected first oscillators 52b to 52f or the second oscillator 53.

[0067] Each receiving unit 13a to 13g has an amplification circuit and an analog-to-digital conversion circuit. As a predetermined process, the received signal (voltage) is amplified by the amplification circuit and then converted into a digital signal (digital value) by the analog-to-digital conversion circuit (AD conversion circuit).

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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, resulting in a significant decrease in azimuth resolution. On the other hand, the distance resolution (distance resolution) in the direction of transmission and reception of ultrasonic TBs by the first transducers 52a to 52f (the direction of the first central axis C1a to C1f) is higher than that of azimuth resolution. Therefore, when the detection result image 22 (see Figure 7) is generated using the original received signals from the first transducers 52a to 52f as is, a large difference in resolution occurs within the detection result image 22.

[0075] Therefore, when the ultrasonic sonar device 1 performs horizontal detection using its sonar function, the filter 14 performs the spatial filtering process shown in Figure 6 on the original received signals from the first transducers 52a to 52f. Figure 6 is a flowchart of this spatial filtering process.

[0076] The spatial filtering process shown in Figure 6 can be broadly classified into three processes. One is the process in S11 to S17, in which a high-pass filter is applied in the azimuthal direction to the received signals obtained from the corresponding first central axes C1a to C1f directions (hereinafter simply referred to as "received signals from the first central axes C1a to C1f") for the first transducers 52a to 52f, in order to improve the resolution in the azimuthal direction. Another is the process in S18, in which a low-pass filter is applied in the distance direction to the received signals from the first central axes C1a to C1f, in order to suppress the resolution in the distance direction. The last is the process in S19 to S28, in which a received signal is generated assuming that ultrasonic TB was virtually transmitted and received in a virtual direction set between the first central axes C1a to C1f (a predetermined direction), thereby improving the resolution in the azimuthal direction.

[0077] Figure 6 shows one specific example of a high-pass filter adapted to the azimuth direction in spatial filtering, and one specific example of a method for generating a virtual received signal in a virtual direction. Now, with reference to Figure 6, we will explain specific examples of spatial filtering.

[0078] Spatial filtering is performed when the ultrasonic sonar device 1 performs horizontal detection using its sonar function, and the filter 14 receives the original received signal from at least the receiving units 13a to 13f to the first transducers 52a to 52f.

[0079] When filter 14 starts spatial filtering, it first performs processing (S11 to S17) to apply a high-pass filter in the azimuth direction to the received signals of the first central axes C1a to C1f. Specifically, it first sets the oscillator number i, a variable that identifies the oscillator, to an initial value of "1" (S11). When oscillator number i is 1, it indicates the first oscillator 52a; when it is 2, it indicates the first oscillator 52b; when it is 3, it indicates the first oscillator 52c; when it is 4, it indicates the first oscillator 52d; when it is 5, it indicates the first oscillator 52e; and when it is 6, it indicates the first oscillator 52f. By setting oscillator number i to 1 in the S11 process, a high-pass filter is first applied to the original received signal of the first oscillator 52a, and the received signal after applying the high-pass filter is calculated.

[0080] Next, filter 14 sets the depth variable j, which corresponds to depth, to an initial value of "0" (S12). Each raw received signal output from receiving units 13a to 13f is associated with the depth variable j, and the value of depth j allows it to be determined which depth's reflected wave intensity level the raw received signal represents. By setting depth j to 0 in the S12 process, a high-pass filter is first applied to the raw received signal that shows the reflected wave intensity level from the shallowest depth detectable by the first transducer 52, and the received signal after applying the high-pass filter is calculated.

[0081] Next, the original received signal RX corresponding to the depth indicated by depth j of the first transducer 52, indicated by transducer number i. ｉA high-pass filter is applied to (j) using the following equation (1), and the received signal RY after applying the high-pass filter is ｉ (j) is calculated (S13).

[0082]

[0083] Here, R ｎ (j) is the value of the original received signal corresponding to the depth indicated by depth j of the first transducer 52, indicated by transducer number n. Also, C iｎ This is the influence component ratio of the first oscillator 52, indicated by oscillator number n, relative to the first oscillator 52, indicated by oscillator number i.

[0084] For example, the reflected waves received by the first transducer 52a include not only the reflected waves caused by the ultrasonic TB transmitted by the first transducer 52a itself, but also the reflected waves caused by the ultrasonic TB transmitted by the other first transducers 52b to 52f. This is also true for the first transducers 52b to 52f other than the first transducer 52a, and in general terms, the first transducer 52 indicated by transducer number i includes not only the reflected waves caused by the ultrasonic TB transmitted by itself, but also the reflected waves caused by the ultrasonic TB transmitted by the first transducer 52 indicated by transducer number other than i.

[0085] Influence component ratio C ｉｎ This is the ratio to which reflected waves originating from ultrasonic TB transmitted from the first transducer 52, indicated by transducer number n, are mixed with reflected waves received by the first transducer 52, indicated by transducer number i, and is determined by the installation position (distance), installation angle, and directional characteristics of each first transducer 52. The influence component ratio C of the first transducer 52, indicated by transducer number i, is also determined. ｉｉ This becomes a positive value, and represents the influence component ratio C of oscillator number n (where n ≠ i) on the first oscillator 52 indicated by oscillator number i. ｉｎ This will result in a negative value.

[0086] For the equation shown in equation (1), the influence component ratio C determined above is used. ｉｎBy using this, as the intensity level of the reflected wave from depth j in a predetermined direction (the direction in which the first vibrator 52 indicated by vibrator number i transmits and receives ultrasonic wave TB; in other words, the direction of the first central axes C1a to C1f of the first vibrator 52) for which the first vibrator 52 indicated by vibrator number i is responsible for detecting the detection target object GF, the intensity level of the reflected wave caused by the ultrasonic wave TB transmitted from the first vibrator 52 indicated by a vibrator number other than vibrator number i is removed, and only the intensity level of the reflected wave caused by the ultrasonic wave TB transmitted from the first vibrator 52 indicated by vibrator number i is extracted and can be used as the received signal in that predetermined direction. As a result, the original received signal RX ｉ (j) is applied with a high-pass filter, and edge enhancement is performed in the azimuth direction, so that the resolution in the azimuth direction can be improved.

[0087] The filter 14 determines whether the depth j is less than a fixed value j ｍａｘ after the process of S13 (S14). The fixed value j ｍａｘ is the value (maximum value) of the depth j indicating the maximum depth at which detection is performed in the direction of the first central axes C1a to C1f in the first vibrator 52.

[0088] As a result of the determination in S14, when the depth j is less than the fixed value j ｍａｘ (S14: Yes), the filter 14 adds 1 to the depth j (S15) and returns to the process of S13. As a result, the high-pass filter according to Equation (1) is applied to the original received signal RX ｉ (j) based on the reflected wave from the next depth j with the value advanced by one. Then, the process of S13 (application of the high-pass filter) to the original received signal of the first vibrator 52 indicated by vibrator number i is repeated until the depth j becomes the fixed value j ｍａｘ . That is, for the first vibrator 52 indicated by vibrator number i, the high-pass filter is applied to all the original received signals RX ｉ (j) from all depths j.

[0089] As a result of the determination in S14, the depth j is fixed at j ｍａｘIf the above is true (S14: No), the filter 14 then determines whether the oscillator number i is less than 6 (S16). If the result of the determination in S16 is that the oscillator number i is less than 6 (S16: Yes), the filter 14 adds 1 to the oscillator number i (S17) and returns to the process in S12. Then, the processes in S12 to S15 are executed on the original received signal of the first oscillator 52 indicated by the new oscillator number i to which 1 has been added.

[0090] As a result, the first transducer 52, indicated by the new transducer number i with 1 added to it, receives the original received signal RX from all depths j. ｉ A high-pass filter is applied to (j). Then, the original received signal RX from all depths j is processed. ｉ The application of a high-pass filter to (j) is performed for all first oscillators 52a to 52f by the processes in S16 and S17. If, as a result of the determination in S16, oscillator number i is 6 or greater (S16: No), the filter 14 finishes the process of applying a high-pass filter in the azimuthal direction to the received signals of the first central axes C1a to C1f and proceeds to the process in S18.

[0091] In the processing of S18, a low-pass filter is applied in the distance direction to the received signal in each of the first central axes C1a to C1f. The low-pass filter is applied to the received signal at depth j (here, the received signal RY after applying the high-pass filter). ｉ This is done by adding (mixing) the received signals of the preceding and succeeding depths (for example, depth (j-1), depth (j+1), etc.) to (j) at a predetermined ratio. Note that this low-pass filter is just one example, and the method is not limited to this. As a result, a low-pass filter is applied to the received signal in the distance direction at each of the first central axes C1a to C1f of the first oscillators 52a to 52f, so that the distance direction becomes smoother and the resolution in the distance direction can be suppressed.

[0092] As described above, in spatial filtering, the azimuthal resolution is improved and the distance resolution is suppressed for the received signals at the first central axes C1a to C1f of the first oscillators 52a to 52f, respectively. Therefore, it is possible to harmonize the azimuthal and distance resolutions overall.

[0093] Next, after the processing in S18, the filter 14 performs a process to generate a received signal that assumes an ultrasonic TB (virtual beam) has been virtually transmitted and received in a virtual direction set between the first central axes C1a and C1f (S19 to S28).

[0094] First, filter 14 sets the virtual beam number k to an initial value of "1" (S19). The virtual beam number k is a variable that identifies the virtual beam that virtually generates the received signal. When the virtual beam number k is 1, it indicates a virtual beam in a virtual direction set at an intermediate position between the first central axis C1a of the first oscillator 52a indicated by oscillator number 1 and the first central axis C1b of the first oscillator 52b indicated by oscillator number 2. Also, when the virtual beam number k is the value "k" (where k is a natural number from 1 to 6), it indicates a virtual beam in a virtual direction set at an intermediate position between the first central axes C1a to C1f of the first oscillator 52 indicated by oscillator number k and the first central axes C1a to C1f of the first oscillator 52 indicated by oscillator number (k+1).

[0095] However, if the virtual beam number k is "6", then (k+1) will be 7, but in this case, the oscillator number (k+1) will refer to oscillator number 1. In other words, virtual beam number 6 indicates a virtual beam in a virtual direction set at an intermediate position between the first central axis C1f of the first oscillator 52f, indicated by oscillator number 6, and the first central axis C1a of the first oscillator 52a, indicated by oscillator number 1. This relationship is assumed to always hold true in the processing of S19 to S28.

[0096] Next, filter 14 sets the depth j to its initial value "0" (S20). Depth j is a variable with the same meaning as described in the process of S12.

[0097] Next, filter 14 processes the virtual received signal RZ at the depth j of the virtual beam indicated by the virtual beam number k. ｋAs preparation for generating (j), the following equation (2) is used to obtain the received signal at depth j of the first oscillator 52 indicated by oscillator number k that straddles the virtual beam (here, the received signal after filtering by processing S11 to S18. The same applies to processing S21 to S24 below.) RY ｋ (j) and the received signal RY at depth j of the first transducer 52 indicated by transducer number (k+1) ｋ＋１ The absolute value DRY of the difference with (j) is calculated (S21).

[0098]

[0099] Next, the filter 14 uses the following equation (3) to calculate the received signal RY of the first oscillator 52, indicated by oscillator number k, at depth j. ｋ From (j), subtract half of the absolute value DRY of the difference calculated by the process in S21 (S22), and using the following equation (4), the received signal RY of the depth j of the first transducer 52 indicated by transducer number (k+1) ｋ＋１ (j) is subtracted by half of the absolute value DRY of the difference calculated by the process in S21 (S23).

[0100]

[0101] Furthermore, the filter 14 uses the following equation (5) to obtain the received signal RY of the first oscillator 52, indicated by oscillator number k, at depth j. ｋ (j) and the received signal RY at depth j of the first transducer 52 indicated by transducer number (k+1) ｋ＋１ After calculating the average value with (j), half of the absolute value of the difference DRY is added to that average value to obtain the virtual received signal RZ at depth j of the virtual beam indicated by virtual beam number k. ｋ (j) (S24). Note that the received signal RY at depth j of the first transducer 52, indicated by transducer number k used in equation (5) ｋ (j) and the received signal RY at depth j of the first transducer 52 indicated by transducer number (k+1) ｋ＋１ (j) is the value before applying equations (3) and (4).

[0102]

[0103] Through the processing in S21 to S24, the filter 14 determines the virtual received signal RZ at the depth j of the virtual beam indicated by the virtual beam number k. ｋ (j) is the received signal RY at depth j of the first transducer 52, indicated by transducer number k. ｋ (j) and the received signal RY at depth j of the first transducer 52 indicated by transducer number (k+1) ｋ＋１ (j) is generated by applying filters represented by equations (2) to (5). This generates not only the received signals in the directions of the first central axes C1a to C1f where the first transducer 52 actually transmits and receives ultrasonic TB, but also virtual received signals in virtual directions located midway between the first central axes C1a to C1f. This makes it possible to increase the number of directions in which ultrasonic TB is transmitted and received, including virtual directions, beyond the actual number of first transducers 52 (i.e., the number of predetermined directions) (in this embodiment, twice the number, or 12 directions). Therefore, the ultrasonic sonar device 1 can improve its azimuth resolution.

[0104] Furthermore, the filter 14 receives the received signal RY at depth j of the first oscillator 52, indicated by oscillator number k. ｋ (j) part and the received signal RY of the first oscillator 52 at depth j, indicated by oscillator number (k+1) ｋ＋１ (j) and a part of them, and a virtual received signal RZ at the depth j of the virtual beam located between them. ｋ Move to (j).

[0105] Assuming a virtual received signal RZ at the virtual beam depth j ｋ (j) is the received signal RY at depth j of the first transducer 52, indicated by transducer number k. ｋ (j) and the received signal RY at depth j of the first transducer 52 indicated by transducer number (k+1) ｋ＋１ If the result is generated by simple interpolation, such as taking the average of (j), the total energy within the screen of the detection result image 22 generated later may increase compared to the total energy of the reflected waves received by the first oscillators 52a to 52f.

[0106] In contrast, in the processing of S21 to S24, a portion of the energy (power) is transferred from the actual received signal of the first transducer 52 to the virtual beam. That is, the filters shown in equations (2) to (5) are filters that can maintain the total energy of the reflected waves received by the first transducers 52a to 52f. In this way, by applying a filter that can maintain the total energy of the received reflected waves to the received signal of each first transducer 52a to 52f that transmits and receives ultrasonic TB in the predetermined direction of the first central axis C1a to C1f, a received signal is generated that assumes ultrasonic waves were virtually transmitted and received in a virtual direction set between the predetermined directions. This suppresses the increase in the total energy in the screen compared to the total energy of the received reflected waves, even when generating a virtual received signal in that virtual direction. Therefore, the ultrasonic sonar device 1 can suppress the detection result image 22 from showing a higher level of reaction than the actual detection result by inserting the received signal in the virtual direction into the detection result image 22.

[0107] After processing in S24, the filter 14 sets the depth j to the aforementioned fixed value j. ｍａｘ Determine if it is less than (S25). Based on the result of the determination in S25, the depth j is fixed value j ｍａｘ If it is less than (S25: Yes), filter 14 adds 1 to depth j (S26) and returns to the process of S21. As a result, the processes of S21 to S24 are executed at the next depth j, which is one value ahead, and the virtual received signal RZ at the next depth j of the virtual beam indicated by virtual beam number k is calculated. ｋ (j) is generated. Then, the virtual received signal RZ of the virtual beam indicated by virtual beam number k is generated. ｋ (j) is a fixed value j for depth j. ｍａｘ This process is repeated until the desired result is reached. That is, the virtual received signal RZ of the virtual beam indicated by virtual beam number k. ｋ (j) is generated for all depths j.

[0108] As a result of S25's judgment, the depth j is fixed. ｍａｘIf the above is true (S25: No), the filter 14 then determines whether the virtual beam number k is less than 6 (S27). If the result of the determination in S27 is that the virtual beam number k is less than 6 (S27: Yes), the filter 14 adds 1 to the virtual beam number k (S28) and returns to the process in S20. Then, the processes in S20 to S26 are executed for the virtual beam indicated by the new virtual beam number to which 1 has been added.

[0109] As a result, for the virtual beam indicated by the new virtual beam number with 1 added, the virtual received signal RZ for all depths j is calculated. ｋ (j) is generated. Then, as a result of the judgment in S27, if the virtual beam number k is 6 or greater (S27: No), a virtual received signal RZ is generated for all virtual beams. ｋ Since (j) has been generated, filter 14 terminates the spatial filtering process.

[0110] Returning to Figure 5, let's continue the explanation. In filter 14, temporal filtering is performed on a received signal indicating the intensity of a reflected wave reflected from a certain 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, from the same direction and depth. This temporal filtering allows the detection result image 22, which will be described later and displayed on the display device 21, to change smoothly over time, so that the user can view the detection result image 22 without any discomfort.

[0111] The filter 14 performs a predetermined filtering process on the original received signals of each of the first transducers 52a to 52f and the second transducer 53. The filter 14 then outputs the values ​​obtained from the filtering process to the detection result image generation means 15, which will be described next, as the received signals of each of the first transducers 52a to 52f and the second transducer 53. If a virtual received signal is generated for a virtual direction, the filter 14 also includes that virtual received signal. The receiving units 13a to 13g and the filter 14 constitute the received signal generation means of the present invention.

[0112] The detection result image generation means 15 generates a 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 22 will now be explained with reference to Figure 7. Figure 7 is a schematic diagram showing the detection result image 22 displayed on the display device 21 when the ultrasonic sonar device 1 performs horizontal detection as a sonar function.

[0113] As shown in Figure 7, the detection result image 22 is a commonly known image of horizontal detection results, and displays the latest detection results for each direction in a circular format for omnidirectional detection of the ship 71. Specifically, based on the received signals for each direction of the first central axes C1a to C1f of the first transducers 52a to 52f output from the filter 14, and virtual received signals for each direction virtually set between those directions, the latest detection results across a predetermined range set for all directions of the ship 71 are displayed on the display device 21 as the detection result image 22.

[0114] The detection result image generation means 15 shown in Figure 5 generates a detection result image 22 using the filtered received signals from the first transducers 52a to 52f, which are input from the filter 14, and virtual received signals for each virtually set direction. The user can determine the current direction of the detected object GF relative to the ship 71 by looking at the detection result image 22 (see Figure 7) displayed on the display device 21.

[0115] Furthermore, as shown in Figure 7, the detection result image 22 displays a first radiation guideline 25 and a second radiation guideline 26. The first radiation guideline 25 corresponds to the first line of the present invention and is a line in the detection result image 22 that indicates the predetermined direction in which ultrasonic TB is transmitted and received by each of the first transducers 52a to 52f, i.e., the direction of the first central axis C1a to C1f. The second radiation guideline 26 corresponds to the second line of the present invention and is a line in the detection result image 22 that indicates the virtual direction, which is the transmission and reception direction of the virtual beam from which a virtual received signal is generated by the filter 14.

[0116] The first radiation guideline 25 and the second radiation guideline 26 are generated by the radiation guideline generation means 15a provided in the detection result image generation means 15, as shown in Figure 5. Specifically, the radiation guideline generation means 15a draws the first radiation guideline 25 in a first manner on the detection result image 22 at a position where the detection results based on the received signals of the first transducers 52a to 52f are displayed, thereby generating the first radiation guideline 25 on the detection result image 22. The radiation guideline generation means 15a also draws the second radiation guideline 26 in a second manner at a position where the detection results based on the virtual received signal related to the virtual beam generated by the filter 14 are displayed, thereby generating the second radiation guideline 26 on the detection result image 22.

[0117] The first embodiment representing the first radiation guideline 25 and the second embodiment representing the second radiation guideline 26 are different embodiments. The first embodiment and the second embodiment may differ in line type, for example, as shown in Figure 7, with the first embodiment being a solid line and the second embodiment being a dashed line, or in line color, for example, with the first embodiment being white and the second embodiment being gray. They may also differ in line width, for example, with the first embodiment having a line width of 1 mm and the second embodiment having a line width of 0.5 mm. Furthermore, the transmittance of each line may differ, for example, with the first embodiment having low transmittance and the second embodiment having high transmittance. In addition, the different embodiments between the first embodiment and the second embodiment may be a combination of two or more line types, line colors, line widths, transmittances, etc., or they may be distinguished by attributes other than those mentioned above.

[0118] When the first radiation guideline 25 generated by the radiation guideline generation means 15a is displayed on the detection result image 22, the user can instantly grasp the predetermined direction, which is the direction of the first central axes C1a to C1f of the first transducers 52a to 52f, from the first radiation guideline 25 displayed on the detection result image 22. In addition, when the second radiation guideline 26 generated by the radiation guideline generation means 15a is displayed on the detection result image 22, the user can instantly grasp the virtual direction of the virtual beam in the detection result image 22 from the second radiation guideline 26 displayed on the detection result image 22.

[0119] Here, the predetermined direction, which is the direction of the first central axes C1a to C1f of the first transducers 52a to 52f, is where ultrasonic TB is actually transmitted and received by the first transducers 52a to 52f, and the object GF is detected, resulting in high detection accuracy. In contrast, the received signal (detection result) of the virtual direction of the virtual beam set midway between the first central axes C1a to C1f is generated by interpolating the received signals of the first transducers 52a to 52f, so its detection accuracy is inferior to that of the predetermined direction, which is the direction of the first central axes C1a to C1f of the first transducers 52a to 52f.

[0120] The detection result image 22 is generated in a way that distinguishes between a predetermined direction with high detection accuracy (the direction of the first central axis C1a to C1f) and a virtual direction between that predetermined direction with lower detection accuracy, using the first radiation guideline 25 and the second radiation guideline 26. This makes it possible to clearly indicate to the user the virtual direction in which the reliability of detection is lower than that of the predetermined direction in which ultrasonic TB was actually transmitted and received, so that the user can check the detection results while considering the reliability of detection in each direction.

[0121] Furthermore, the detection result image 22 is generated such that the first radiation guideline 25 is represented in a first manner for a predetermined direction, and the second radiation guideline 26 is represented in a second manner different from the first manner for a virtual direction. This allows the user to instantly determine from the detection result image 22 the predetermined direction and the virtual direction where the reliability of detection is lower.

[0122] The first radiation guideline 25 and the second radiation guideline 26 can also be seen as enabling the determination of the reliability of the received signals generated in each direction from the detection result image 22. As a result, in the detection result image 22, where a predetermined direction with high detection reliability and a virtual direction with lower detection reliability are mixed, the user can easily grasp the reliability within the detection result image 22 and confirm the detection results.

[0123] Furthermore, in the detection result image 22, the manner in which the reliability of the detection result is represented is not limited to being represented by straight lines such as the first radiation guideline 25 and the second radiation guideline 26, but may also be represented by different background colors in the areas where the detection result is displayed in the detection result image 22. That is, in the detection result image 22, the background color of the area around the position (direction) where the detection result for a predetermined direction with high reliability is displayed may be different from the background color of the area around the position (direction) where the detection result for a virtual direction with lower reliability is displayed.

[0124] Furthermore, in the detection result image 22, the background color of the area between the predetermined direction and the virtual direction may be expressed as a gradient by differentiating the background color of the area where the detection result for a predetermined direction with high reliability is displayed and the background color of the area where the detection result for a virtual direction with lower reliability is displayed, while interpolating the background color of the area between them with the colors of both. In this way, even in the detection result image 22 where a predetermined direction with high detection reliability and a virtual direction with lower detection reliability are mixed due to the transmission and reception of ultrasonic TB, the user can easily grasp the reliability of detection in each direction and check the detection results.

[0125] Returning to Figure 5, the explanation continues. The display control means 18 controls the display device 21 to display the detection result image 22 generated by the detection result image generation means 15, as well as other images. For example, the display control means 18 adjusts the size and display position of the detection result image 22, and also combines characters, symbols, figures, etc., with the detection result image 22 to display a single image on the display device 21.

[0126] Next, a method for performing horizontal detection using the sonar function of the ultrasonic sonar device 1 of this embodiment, configured as described above, will be explained.

[0127] 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.

[0128] The ultrasonic sonar device 1 outputs drive signals from the transmitting unit 11a and the transmitting unit 11b, and for a predetermined time, the first transducers 52a to 52f and the second transducer 53 of the transmitting and receiving unit 50 transmit ultrasonic TB 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 TB transmitted from each of the first central axes C1a to C1f, ultrasonic TB is transmitted to the ship 71 in all directions.

[0129] 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.

[0130] 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, converted into digital signals (digital values), and output as received signals (original received signals) in the directions of the first central axis C1a to C1f and the second central axis C2.

[0131] These raw received signals are subjected to spatial (and temporal) filtering by filter 14. When the ultrasonic sonar device 1 performs horizontal detection using its sonar function, filter 14 performs spatial filtering as shown in Figure 6. This spatial filtering applies a high-pass filter in the azimuthal direction to the received signals along the first central axis C1a to C1f, improving the resolution in the azimuthal direction where the resolution is low, and applies a low-pass filter in the distance direction, suppressing the resolution in the distance direction where the resolution is high. As a result, the overall resolution in the azimuthal and distance directions is harmonized.

[0132] Furthermore, the filter 14 sets a virtual direction at an intermediate position between adjacent first central axes C1a to C1f for each of the first central axes C1a to C1f, and generates a received signal from the received signals of the first transducers 52a to 52f that assumes that ultrasonic TB was virtually transmitted and received in that virtual direction. This makes it possible to increase the number of directions in which ultrasonic TB was transmitted and received, including the virtual direction, beyond the actual number of first transducers 52 (i.e., the number of predetermined directions). In addition, the filter 14 generates a virtual received signal in the virtual direction while suppressing the total energy in the screen from exceeding the total energy of the reflected waves received by the first transducers 52a to 52f. By inserting the received signal in the virtual direction into the detection result image 22, it is possible to suppress the detection result image 22 from showing a higher level of reaction than the actual detection result.

[0133] The filtered received signals from the first central axis C1a to C1f and the second central axis C2, output by the filter 14, and the virtual received signals from the virtual directions virtually set between each of the first central axes C1a to C1f are input to the detection result image generation means 15.

[0134] Then, for the omnidirectional detection of the ship 71, a detection result image 22 is generated by the detection result image generation means 15, which displays the latest detection results for each directional direction in a circular format. At this time, the radiation guideline generation means 15a generates a first radiation guideline 25 in the detection result image 22, which represents a predetermined direction in which ultrasonic TB is transmitted and received by each of the first transducers 52a to 52f, and a second radiation guideline 26, which represents the transmission and reception direction of the virtual beam for which a virtual received signal is generated by the filter 14. Then, the detection result image 22 with these first radiation guideline 25 and second radiation guideline 26 drawn on it is displayed on the display device 21 by the display control means 18, as shown in Figure 7.

[0135] The first radiation guideline 25 and the second radiation guideline 26 clearly indicate to the user a virtual direction in which the reliability of detection is lower than that of the predetermined direction in which ultrasonic TB was actually transmitted and received. Therefore, the user can check the detection results while taking into account the reliability of detection in each direction.

[0136] With the ultrasonic sonar device 1 configured as described above, the transmitting and receiving unit 50 is driven by the transmitting units 11a and 11b to transmit ultrasonic TB into the water from the first transducers 52a to 52f and the second transducer 53 in all directions relative to the vessel 71 set within a predetermined range. Then, for each predetermined direction, the first central axis C1a to C1f and the second central axis C2, the reflected waves of ultrasonic TB reflected from each position in the water are received by the first transducers 52a to 52f and the second transducer 53 of the transmitting and receiving unit 50, respectively. Based on the reflected waves received by the transmitting and receiving unit 50, a received signal is generated for each predetermined direction by the receiving units 13a to 13g and the filter 14.

[0137] Based on the received signals generated for each predetermined direction, the detection result image generation means 15 generates a detection result image 22 showing the latest detection results over a predetermined range. From this detection result image 22, it is possible to determine at least whether or not there is a target object GF in the predetermined range and the direction in which the target object GF is currently located.

[0138] Here, each of the multiple first transducers 52a to 52f is fixed in the transmitting / receiving unit 50 such that its first central axis C1a to C1f is in a predetermined direction, and when the transmitting / receiving unit 50 is attached to the ship 71, its first central axis C1a to C1f is positioned at a predetermined angle θ with respect to the vertical direction. Each of the first transducers 52a to 52f has predetermined directional characteristics that include at least the first central axes C1a to C1f of adjacent first transducers 52a to 52f, and the vertical direction. As a result, with a small number of first transducers 52a to 52f, ultrasonic TB can be transmitted simultaneously over a predetermined range, and the reflected waves can be received to detect the object GF to be detected. Therefore, the ultrasonic sonar device 1 can achieve high-speed detection at low cost.

[0139] Furthermore, if ultrasonic TB is transmitted and received using a small number of first transducers 52a to 52f, there is a risk that the azimuthal resolution will be greatly reduced. However, with the filter 14, each of the multiple first transducers 52a to 52f receives the reflected wave, and a high-pass filter is applied in the azimuthal direction to the original received signal which indicates the intensity of the reflected wave in a predetermined direction (the direction of the first central axis C1a to C1f), while a low-pass filter is applied in the distance direction, thereby generating received signals for each predetermined direction. As a result, the azimuthal resolution can be improved while the distance resolution can be suppressed, thus achieving a balance between the azimuthal and distance resolutions overall. Therefore, high-speed detection can be realized inexpensively, and the resolution in the azimuthal and distance directions can be harmonized.

[0140] Furthermore, by applying a filter capable of maintaining the total energy of the received reflected waves to the received signal for each predetermined direction, the filter 14 generates a received signal that assumes ultrasonic waves were virtually transmitted and received in a virtual direction set between the predetermined directions. As a result, the received signal in the virtual direction is inserted between the predetermined directions, improving the resolution in the azimuth direction. In addition, since the received signal in the virtual direction is generated while maintaining the total energy of the received reflected waves, it is possible to suppress the increase in the total energy on the screen compared to the total energy of the received reflected waves when the received signal in the virtual direction is inserted. Therefore, by inserting the received signal in the virtual direction, it is possible to suppress the detection result image 22 from showing a higher level of reaction than the actual detection result.

[0141] Furthermore, in the detection result image 22 generated by the detection result image generation means 15, a first radiation guideline 25 indicating a predetermined direction and a second radiation guideline 26 indicating a virtual direction are displayed, so the user can determine the predetermined direction and the virtual direction in the detection result image 22. This makes it possible to clearly indicate to the user the virtual direction in which the reliability of detection is lower than that of the predetermined direction in which ultrasonic TB was actually transmitted and received, so the user can check the detection results while considering the reliability of detection in each direction.

[0142] Furthermore, the ultrasonic sonar device 1 according to this embodiment achieves the effects described above through its other configurations.

[0143] 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.

[0144] The high-pass filter applied in the azimuthal direction to the received signals along the first central axes C1a to C1f in the spatial filtering process shown in Figure 7, as described in the above embodiment, is just one specific example. The filter applied in the azimuthal direction to the received signals along the first central axes C1a to C1f is a high-pass filter, and is not limited to the example shown in the above embodiment.

[0145] In the above embodiment, the spatial filtering process shown in Figure 7 describes a case where a high-pass filter is first applied in the azimuthal direction to the original received signal on the first central axis C1a to C1f, and then a low-pass filter is applied in the distance direction. However, it is also possible to apply a low-pass filter first in the distance direction to the original received signal on the first central axis C1a to C1f, and then a high-pass filter in the azimuthal direction. Furthermore, it is also possible to apply both a high-pass filter in the azimuthal direction and a low-pass filter in the distance direction simultaneously to the original received signal on the first central axis C1a to C1f.

[0146] The filter applied to generate a virtually received signal in a virtual direction set between the first central axes C1a to C1f (a predetermined direction) in the spatial filtering process shown in Figure 7 described in the above embodiment (processing S19 to S28) is just one specific example, and the filter used to generate the virtually received signal is not limited to the example shown in the above embodiment. However, as in the above embodiment, it is desirable that the filter is capable of maintaining the total energy of the reflected waves received by the first oscillators 52a to 52f.

[0147] In the above embodiment, the case in which the transmitter / receiver unit 50 is equipped with a second transducer 53 whose second central axis C2 is in the vertical direction directly below the ship 71 was described. However, at least when performing horizontal detection as a sonar function, detection in the vertical direction directly below the ship 71 may not always be necessary. Also, in the above embodiment, since the directional characteristics of the ultrasonic TB transmitted from the first transducers 52a to 52f include the vertical direction directly below the ship 71, it is possible to detect an object GF located in the vertical direction directly below the ship 71 using only the first transducers 52a to 52f, although the detection sensitivity and / or accuracy will decrease. Therefore, the second transducer 53 may be omitted from the transmitter / receiver unit 50.

[0148] 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 θ 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°.

[0149] 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 make a predetermined angle θ 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.

[0150] 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 direction of the vessel 71. In this case as well, the first range may be set to a part or all of the predetermined range. Furthermore, the second range may be set to a part or all of the predetermined range, insofar as it differs from the first range.

[0151] 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 Detection result image generation means 15a Radiation guideline generation means 18 Display control means 21 Display device 22 Detection result image 25 First radiation guideline 26 Second radiation guideline 50 Transmitting and 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 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 Detection target SB Bottom TB Ultrasonic wave θ Angle

Claims

1. A transmitting and receiving unit capable of transmitting ultrasonic waves over a predetermined range in water and receiving reflected ultrasonic waves reflected from each position in the water in each predetermined direction; a receiving signal generation means that generates a received signal for each predetermined direction based on the reflected waves received by the transmitting and receiving unit; and a detection result image generation means that generates a detection result image showing the latest detection result over the predetermined range based on the received signals for each predetermined direction generated by the receiving signal generation means, wherein the transmitting and receiving unit comprises a plurality of first transducers having predetermined directional characteristics with respect to a central axis, each of the plurality of first transducers having its central axis in the predetermined direction and fixed such that the central axis is at a predetermined angle with respect to the vertical direction when the transmitting and receiving unit is attached to a ship, and having predetermined directional characteristics that include at least the central axis of an adjacent first transducer and the vertical direction, and the receiving signal generation means An ultrasonic sonar device characterized by applying a high-pass filter in the azimuthal direction and a low-pass filter in the distance direction to the intensity of the reflected wave obtained for each of the plurality of first transducers by each of the first transducers receiving the reflected wave, and then generating the received signal for each predetermined direction.

2. The ultrasonic sonar device according to claim 1, characterized in that the receiving signal generation means applies a filter capable of maintaining the total energy of the received reflected waves to the receiving signal for each predetermined direction, thereby generating a receiving signal that assumes ultrasonic waves were virtually transmitted and received in a virtual direction set between the predetermined directions.

3. The ultrasonic sonar device according to claim 2, characterized in that the detection result image generation means generates the detection result image in a manner that allows for determination of the predetermined direction and the virtual direction.

4. The ultrasonic sonar device according to claim 3, characterized in that the detection result image generation means generates the detection result image such that a first line is represented in a first manner with respect to the predetermined direction, and a second line is represented in a second manner different from the first manner with respect to the virtual direction.

5. The ultrasonic sonar device according to claim 2, characterized in that the detection result image generation means generates the detection result image in such a way that the reliability of the received signals generated in each direction can be determined.

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