Ultrasonic Sonar Device

Abstract

The ultrasonic sonar device comprises a wave transmitting / receiving unit capable of transmitting ultrasonic waves over a predetermined range underwater and receiving reflected waves of the ultrasonic waves reflected from each position underwater in each predetermined direction, and a detection result image generating means for generating a detection result image showing the latest detection result over the predetermined range, wherein each of a plurality of first transducers provided in the wave transmitting / receiving unit is fixed so that its central axis is in the predetermined direction and has a predetermined directional characteristic that includes at least the central axis of an adjacent first transducer and the vertical direction, and a high-pass filter is applied in the azimuth direction to the intensity of the reflected wave obtained from each first transducer (S11 to S17) and a low-pass filter is applied in the distance direction (S18), and a received signal for each predetermined direction is generated.

Description

[Technical field]

[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. [Background technology]

[0002] There is known an ultrasonic sonar device that detects a detection target such as a school of fish over a predetermined range underwater by transmitting and receiving ultrasonic waves. A general fish detection device detects a detection target in a vertical direction from a ship, whereas an ultrasonic sonar device can detect a detection target present around a ship by horizontal detection, vertical cross-sectional detection, etc. Known examples of ultrasonic sonar devices include PPI sonar (searchlight sonar) and scanning sonar.

[0003] PPI sonar emits (transmits) a thin beam of ultrasonic waves and has a transducer that can rotate or pivot to receive the reflected waves from the object to be detected, and detects the underwater area around the ship while changing the direction of ultrasonic emission (for example, Patent Document 1). The transducer has a simple structure, so it can be constructed at low cost, but it takes time to complete one detection over a specified range.

[0004] Scanning sonar performs underwater detection around a ship by forming multiple minute transducers in an array on the surface of a cylinder, sphere, etc., and transmitting ultrasonic waves from each transducer simultaneously and receiving the reflected waves (for example, Patent Document 2). While a single detection over a given range can be performed in a short time, the transducer array is complex and the transmission and reception circuitry for transmitting and receiving ultrasonic waves in each transducer is large, making the system expensive. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2019-066208 A [Patent Document 2] JP 2019-200204 A Summary of the Invention [Problem to be solved by the invention]

[0006] In contrast to such conventional ultrasonic sonar devices, the inventor has invented an ultrasonic sonar device that can achieve high-speed detection at low cost by simultaneously transmitting ultrasonic waves over a specified 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 required before this device can be brought to market as a product.

[0007] The present invention has been made in consideration of the above circumstances, and has an object to provide an ultrasonic sonar device that can achieve high-speed detection at low cost and can achieve a good balance between resolution in the azimuth direction and distance direction. [Means for solving the problem]

[0008] In order to achieve this object, a first aspect of the present invention includes a wave transmitting and receiving unit capable of transmitting ultrasonic waves over a predetermined range underwater and receiving reflected waves of the ultrasonic waves reflected from each position underwater for each predetermined direction, a reception signal generating means for generating a reception signal for each of the predetermined directions based on the reflected waves received by the wave transmitting and receiving unit, and a detection result image generating means for generating a detection result image showing the latest detection result over the predetermined range based on the reception signal for each of the predetermined directions generated by the reception signal generating means, wherein the wave transmitting and receiving unit includes a plurality of first transducers having a predetermined directional characteristic with respect to a central axis, and the plurality of first transducers are arranged to receive the reflected waves of the ultrasonic waves reflected from each of the positions underwater for each predetermined direction. Each of the first transducers has its central axis in the predetermined direction, is fixed so that the central axis is at a predetermined angle with respect to the vertical direction when the transmitting and receiving unit is attached to the ship, and has the predetermined directional characteristic to include at least the central axis of an adjacent first transducer and the vertical direction, and the received signal generating 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 first transducers when each of the multiple first transducers receives the reflected wave, and then generates the received signal for each of the predetermined directions.

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

[0010] A third aspect of the present invention is the ultrasonic sonar device according to the second aspect, wherein the detection result image generating means generates the detection result image so that the predetermined direction and the virtual direction can be distinguished.

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

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

[0013] According to the ultrasonic sonar device of the first aspect of the present invention, ultrasonic waves are transmitted by the wave transmitting / receiving unit over a predetermined range underwater. Then, the reflected waves of the ultrasonic waves reflected from each position underwater for each predetermined direction are received by the wave transmitting / receiving unit. Based on the reflected waves received by the wave transmitting / receiving unit, a received signal is generated for each predetermined direction by the received signal generating means. Based on the generated received signals for each predetermined direction, a detection result image showing the latest detection result over the predetermined range is generated by the detection result image generating means. From this detection result image, it is possible to determine the presence or absence of a detection target within the predetermined range and the location where the detection target is located.

[0014] Here, a plurality of first transducers are fixed to the transducer unit so that their central axes are oriented in a predetermined direction and are positioned at a predetermined angle with respect to the vertical direction when the transducer unit is attached to the ship. Each first transducer has a predetermined directional characteristic that includes at least the central axis of the adjacent first transducer and the vertical direction. This allows a small number of first transducers to simultaneously transmit ultrasonic waves over a predetermined range and receive the reflected waves to detect the detection target. This allows high-speed detection to be achieved at low cost.

[0015] In addition, when transmitting and receiving ultrasonic waves using a small number of first transducers, there is a risk that the resolution in the azimuth direction will be significantly reduced, but the reception signal generating means applies a high-pass filter in the azimuth direction to the intensity of the reflected wave obtained for each first transducer by each of the multiple first transducers receiving the reflected wave, while applying a low-pass filter in the distance direction to generate a reception signal for each predetermined direction. This makes it possible to improve the resolution in the azimuth direction while suppressing the resolution in the distance direction, so that the resolution in the azimuth direction and the resolution in the distance direction can be harmonised as a whole. Therefore, there is an effect that high-speed detection can be realized at low cost, and the resolution in the azimuth direction and the resolution in the distance direction can be harmonised.

[0016] According to the ultrasonic sonar device of the second aspect, in addition to the effects of the ultrasonic sonar device of the first aspect, the following effects are achieved. That is, by applying a filter capable of maintaining the total energy of the received reflected wave to the received signal for each predetermined direction, a received signal assuming that ultrasonic waves are virtually transmitted and received in a virtual direction set between the predetermined directions is generated by the received signal generating means. As a result, since the received signal in the virtual direction is inserted between the predetermined directions, it is possible to improve the resolution in the azimuth direction. In addition, since the received signal in the virtual direction is generated in a manner that maintains the total energy of the received reflected wave, it is possible to suppress the total energy in the screen from increasing more than the total energy of the received reflected wave when the received signal in the virtual direction is inserted. Therefore, it is possible to suppress the detection result image from showing a reaction at a higher level than the actual detection result by inserting the received signal in the virtual direction.

[0017] The ultrasonic sonar device according to the third aspect has the following effect in addition to the effect of the ultrasonic sonar device according to the second aspect. That is, the predetermined direction and the virtual direction can be determined in the detection result image generated by the detection result image generating means. This makes it possible to clearly indicate to the user the virtual direction in which the detection reliability is lower than the predetermined direction in which the ultrasonic waves were actually transmitted and received, so that the user can check the detection result while taking into account the detection reliability of each direction.

[0018] The ultrasonic sonar device according to the fourth aspect has the following effect in addition to the effect of the ultrasonic sonar device according to the third aspect. That is, the detection result image is generated by the detection result image generating means so that the first line is represented in a first aspect with respect to the predetermined direction and the second line is represented in a second aspect different from the first aspect with respect to the virtual direction. This has the effect of allowing the user to distinguish at a glance from the detection result image between the predetermined direction and the virtual direction in which the detection reliability is low.

[0019] The ultrasonic sonar device according to the fifth aspect has the following effect in addition to the effect of the ultrasonic sonar device according to the second aspect. That is, the reliability of the received signal generated in each direction can be determined from the detection result image generated by the detection result image generating means. This has the effect that in a detection result image in which a predetermined direction with high detection reliability by actual transmission and reception of ultrasonic waves and a virtual direction with low detection reliability are mixed, the user can check the detection result while easily grasping the detection reliability in the detection result image. [Brief description of the drawings]

[0020] [Figure 1] 1 is a schematic diagram showing a configuration of an ultrasonic sonar device according to an embodiment of the present invention; [Diagram 2] 2 is a schematic side view showing the state in which the ultrasonic sonar device is mounted on a ship and used for underwater detection. FIG. [Diagram 3]FIG. 2A is a schematic cross-sectional view showing a wave transmitting and receiving unit of the ultrasonic sonar device, and FIG. 2B is a schematic perspective view showing an arrangement of a plurality of first transducers and a second transducer that constitute the wave transmitting and receiving unit. [Figure 4] (a) is a diagram showing a schematic diagram of the first central axis of each of the first transducers when viewed vertically from above the ship, (b) is a diagram showing a schematic diagram of the first central axis when viewed horizontally from the front side of the ship, (c) is a diagram showing a schematic diagram of the directional characteristics of ultrasound transmitted from the first transducers, and (d) is a diagram showing the directional characteristics of ultrasound transmitted from the first transducers when viewed from the front side of the ship. [Diagram 5] FIG. 2 is a block diagram showing the electrical configuration of the ultrasonic sonar device. [Figure 6] 13 is a flowchart showing a spatial filtering process. [Figure 7] 2 is a diagram showing an example of a display screen displayed on a display device of the ultrasonic sonar device. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, the 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, the numerical values, shapes, materials, components, arrangement positions and connection forms of the components 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 that are not described in the independent claims showing the highest concept of the present invention will be described as optional components. In addition, in each drawing, substantially the same configuration is given the same reference numeral, and duplicated explanations will be omitted or simplified.

[0022] First, an ultrasonic sonar device 1 according to an embodiment of the present invention will be described with reference to Figures 1 and 2. Figure 1 is a schematic diagram showing the configuration of the ultrasonic sonar device 1, and Figure 2 is a schematic diagram showing a side view of a ship 71 equipped with the ultrasonic sonar device 1 performing underwater detection.

[0023] 1 and 2, the ultrasonic sonar device 1 is mounted on a ship 71 and has at least a sonar function of horizontally detecting detection targets GF, such as schools of fish, over a predetermined range around the ship 71 in the waters of the sea, lake, river, or the like on which the ship 71 floats. Horizontal detection is a predetermined range in all directions as seen from the ship 71, and detects detection targets GF included in the predetermined range. The ultrasonic sonar device 1 may have a sonar function of performing vertical cross-sectional detection in addition to horizontal detection, and may also have a fish detection function of detecting detection targets GF present in the vertical direction directly below the ship 71 and displaying the detection results in a chronological order.

[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 formed integrally with the main body 5, a wave transmission / reception unit 50 that transmits and receives ultrasonic waves TB for detecting a detection target GF, and a lifting device 41 that raises and lowers the wave transmission / reception unit 50. The main body 5, the operation button 31, and the display device 21 are disposed in the wheelhouse of the ship 71, while the wave transmission / reception unit 50 and the lifting device 41 are disposed in the bottom of the ship 71. The wave transmission / reception unit 50 is raised and lowered by the lifting device 41, so that it can freely appear and disappear underwater from the bottom of the ship 71.

[0025] The operation button 31 is a button that can be operated by the user, and is operated when the user issues various instructions or settings to the ultrasonic sonar device 1. For example, the user operates the operation button 31 to turn the ultrasonic sonar device 1 on / off, set the brightness of the image displayed by the display device 21, and issue instructions to start / end execution of horizontal detection using the sonar function.

[0026] 2, the ultrasonic sonar device 1 transmits (radiates) ultrasonic waves TB in a cone shape within a predetermined range from the wave transmitting and receiving unit 50 with the wave transmitting and receiving unit 50 protruding from the bottom of the ship 71. The wave transmitting and receiving unit 50 is configured to be able to receive reflected waves of the ultrasonic waves TB reflected from a detection target GF included in the predetermined cone-shaped range, the bottom of the sea or lake (hereinafter collectively referred to as the "bottom SB"). The detailed configuration of the wave transmitting and receiving 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 reception signal generated by receiving units 13a-13g, which will be described later, and a filter 14 (see FIG. 5) when the transmitting / receiving unit 50 receives the reflected wave of the ultrasonic wave TB, and is configured, for example, with a liquid crystal display or an organic EL (Electro-Luminescence) display. When the ultrasonic sonar device 1 executes horizontal detection using the search function, a detection result image 22 and the like are displayed on the display device 21. Details of the detection result image 22 will be described later with reference to FIG. 7.

[0028] Next, a detailed configuration of the wave transmitting and receiving unit 50 will be described with reference to Fig. 3 and Fig. 4. Fig. 3(a) is a schematic cross-sectional view showing the wave transmitting and receiving unit 50, and Fig. 3(b) is a schematic perspective view showing an arrangement of a plurality of first transducers 52 (52a to 52f) and a second transducer 53 that constitute the wave transmitting and receiving unit 50.

[0029] 4(a) is a diagram showing the first central axes C1a-C1f of the first transducers 52a-52f when viewed vertically from above the ship 71, and FIG. 4(b) is a diagram showing the first central axes C1a-C1f of the first transducers 52a-52f when viewed horizontally from the front side of the ship 71. FIG. 4(c) is a diagram showing the directional characteristics of ultrasonic waves TB transmitted from adjacent first transducers 52a, 52b, and 52f, and FIG. 4(d) is a diagram showing the directional characteristics of ultrasonic waves TB transmitted from the first transducers 52a and 52d when viewed from the front side of the ship 71.

[0030] As shown in FIG. 3, the wave transmitting / receiving unit 50 has a structure in which a plurality of (six in the example shown in FIG. 3) first transducers 52 (first transducer 52a, first transducer 52b, first transducer 52c, first transducer 52d, first transducer 52e, first transducer 52f) that transmit ultrasonic waves TB in a predetermined direction and receive the reflected waves are housed in a case 51 and molded. Each of the first transducers 52 is a disk-shaped structure having the same size and shape. Similarly to the first transducer 52, the second transducer 53 also has a disk-shaped shape. 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 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 disk-shaped resin plate material that also serves as an acoustic matching layer, and is made of, for example, glass epoxy.

[0032] The piezoelectric element 55 is a plate-like object made of piezoelectric ceramics, and for example, a disk-shaped plate-like object made of lead zirconate titanate (PZT) is used. The piezoelectric element 55 has a front electrode (not shown) formed on its front surface, which is entirely bonded to the base material 54 via an adhesive layer (not shown), and a rear electrode (not shown) formed on its rear surface opposite the front surface. Lead wires are electrically connected to the front electrode and the rear electrode, respectively.

[0033] When a driving voltage is applied from a transmitting unit 11a or a transmitting unit 11b (see FIG. 5) described later via a front electrode and a back electrode, the piezoelectric element 55 deforms in the thickness direction to vibrate the base material 54. This vibration of the base material 54 causes each of the first oscillator 52 and the second oscillator 53 to generate an ultrasonic wave TB.

[0034] In addition, when the reflected wave of the ultrasonic wave TB vibrates the substrate 54 of each of the first transducer 52 and the second transducer 53, the vibration deforms the piezoelectric element 55, generating a voltage between the front electrode and the back electrode. The first transducers 52a-52f and the second transducer 53 output the voltage generated between the front electrode and the back electrode to the corresponding receiving units 13a-13g, which will be described later, to generate reception signals corresponding to the reflected wave received by each of the first transducers 52a-52f and the second transducer 53.

[0035] The case 51 has an opening at one end, and a plurality of first transducers 52 and second transducers 53 are housed in the case 51. The second transducer 53 is disposed at the center of the case 51. Six first transducers 52 are disposed around the second transducer 53 in the order of the first transducer 52a, the first transducer 52b, the first transducer 52c, the first transducer 52d, the first transducer 52e, and the first transducer 52f, in a counterclockwise direction as viewed from the front surface side of the base material 54. The acoustic radiation surface formed on the front surface of the base material 54 of each of the first transducers 52 and the acoustic radiation surface formed on the front surface of the base material 54 of the second transducer 53 are all located on one imaginary spherical surface.

[0036] In this embodiment, the number of first transducers 52 is six, 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 is large, the configuration of the ultrasonic sonar device 1 becomes complicated, large, and expensive, so the number of first transducers 52 is preferably ten or less, and more preferably eight or less.

[0037] Here, the direction of the first central axis C1a (which can also be said to be the direction of the normal vector of the first oscillator 52a) that is the central axis perpendicular to the center of the front surface (sound radiation surface) of the base material 54 can be understood as the sound radiation direction of the first oscillator 52a. Similarly to the first oscillator 52a, the first oscillator 52b is defined as the first central axis C1b, the first oscillator 52c is defined as the first central axis C1c, the first oscillator 52d is defined as the first central axis C1d, the first oscillator 52e is defined as the first central axis C1e, and the first oscillator 52f is defined as the first central axis C1f. Each of the first central axes C1b to C1f can be understood as the sound radiation direction of the corresponding first oscillator 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 base material 54 (which can also be said to be the direction of the normal vector of the second oscillator 53), can be understood to be the acoustic radiation direction of the second oscillator 53.

[0039] That is, the first central axes C1a to C1f 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 to a predetermined range, which is the detection range of the detection target GF, and for receiving the reflected waves.

[0040] Here, the wave transmitting / receiving unit 50 is attached to the ship 71 so 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 waves 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 the detection target GF in the vertical direction with high accuracy. Note that it is preferable that the directional characteristics of the ultrasonic waves TB transmitted from the second transducer 53 are a narrow beam with a small directional angle. This can further increase the accuracy of detection of the detection target GF in the vertical direction.

[0041] On the other hand, in the wave transmitting and receiving unit 50, the first transducers 52a-52f are arranged with the sound emitting surface of each of the first transducers 52a-52f inclined such that the first central axes C1a-C1f form a predetermined angle θ with respect to the second central axis C2 (i.e., the vertical direction when the wave transmitting and receiving unit 50 is attached to the ship 71), as shown in Fig. 3. As a result, the sound emitting direction of each of the first transducers 52a-52f faces in a direction different from the vertical direction directly below the ship 71, as shown in Fig. 4(b).

[0042] In this embodiment, the first transducers 52a-52f are inclined with their acoustic radiation surfaces facing inward (toward the side where the second transducer 53 is located) (see FIG. 3). In this case, it is preferable that each of the first central axes C1a-C1f forms a predetermined angle θ with respect to the second central axis C2, the angle being selected from a range of 20° or more and 50° or less. In this embodiment, the predetermined angle θ is 30°. As shown in FIG. 3(a), each of the first central axes C1a-C1f and the second central axis C2 are converged at one point.

[0043] 4(a), when the wave transmitting / receiving unit 50 is attached to the ship 71 and viewed vertically from above the ship 71, the first central axes C1a to C1f of the first transducers 52a to 52f are disposed at equal intervals in the azimuth direction so that adjacent first central axes C1a to C1f form the same angle δ. When the number of first transducers 52 is n, the angle δ is (360 / n)° (when the number of first transducers 52 is six, the angle δ is 60°).

[0044] As a result, the transmitting and receiving unit 50 can transmit ultrasonic waves TB simultaneously in each of the predetermined directions indicated by the first central axes 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 the predetermined directions.

[0045] 4(a) and 4(b), the wave transmitting / receiving unit 50 is attached to the ship 71 so that, when the ship 71 is viewed vertically from above, the first central axis C1a faces the rightward direction with respect to the longitudinal direction of the ship 71, and the first central axes C1b to C1f are arranged counterclockwise from the first central axis C1a at intervals of an angle δ. In addition, in the present embodiment, an example is shown in which the first transducers 52a to 52f are arranged so that the first central axes C1a to C1f of the first transducers 52a to 52f are equally spaced apart in the azimuth direction, but it is sufficient that the first transducers 52a to 52f can transmit ultrasonic waves TB simultaneously in each of the predetermined directions indicated by the first central axes C1a to C1f over a predetermined range set in all azimuth directions of the ship 71, and the intervals between the first central axes C1a to C1f may vary.

[0046] The directional characteristics of the ultrasonic waves TB transmitted from each of the first transducers 52a to 52f are set to include the first central axes C1a to C1f of the adjacent first transducers 52. For example, as shown in Fig. 4(c), the directional characteristics of the ultrasonic waves 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 waves TB transmitted from the first transducer 52b and the directional characteristics of the ultrasonic waves TB transmitted from the first transducer 52f are both set to include the first central axis C1a of the first transducer 52a. Although not shown in the figure, the directional characteristics of the ultrasonic waves TB transmitted from the first transducer 52b are also set to include the first central axis C1c of the first transducer 52c adjacent to the first transducer 52a on the opposite side, and the directional characteristics of the ultrasonic waves TB transmitted from the first transducer 52f are also set to include the first central axis C1e of the first transducer 52e adjacent to the first transducer 52a on the opposite side.

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

[0049] As described above, the ultrasonic waves TB transmitted from each of the first transducers 52a-52f include the first central axes C1a-C1f of the adjacent first transducers 52, and the directivity is set so as to include the vertical direction when the transducer unit 50 is attached to the ship 71. As a result, by simultaneously driving each of the first transducers 52a-52f, the transducer unit 50 irradiates ultrasonic waves TB from each of the first transducers 52a-52f in the direction of the respective first central axes C1a-C1f, and due to the directivity of the ultrasonic waves TB, it is possible to simultaneously transmit the ultrasonic waves TB to a predetermined range set in all directions of the ship 71 using a small number of first transducers 52.

[0050] Furthermore, the directions of the first central axes C1a-C1f of the first transducers 52a-52f and the directional characteristics of the ultrasonic waves TB radiated from the first transducers 52a-52f are fixed so that the ultrasonic waves TB are radiated over a predetermined range from the wave transmitting / receiving unit 50. This makes it possible to eliminate the need for circuits for controlling the directions of the first central axes C1a-C1f of the first transducers 52a-52f and circuits for controlling the directional characteristics of the ultrasonic waves TB radiated from the first transducers 52a-52f.

[0051] The wave transmitting / receiving unit 50 can receive the reflected waves of the ultrasonic waves TB reflected from the detection target GF present within the predetermined range by the first transducers 52a-52f corresponding to each of the first central axes C1a-C1f, which are predetermined directions. As described above, the ultrasonic sonar device 1 can be constructed to perform high-speed detection in a small size at low cost.

[0052] The wave transmitting / receiving unit 50 is arranged and housed in the case 51 with the first transducers 52a-52f and the second transducer 53 closely packed together so that the first central axes C1a-C1f and the second central axis C2 are respectively in the above-mentioned directions, and is fixed by a filler. As the filler, a waterproof resin material (e.g., urethane resin, etc.) is used, which has a lower specific acoustic impedance than the base material 54 that is the acoustic matching layer of the first transducer 52 and the second transducer 53. The filler is filled so that the outer surface 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 Fig. 5. Fig. 5 is a block diagram showing the electrical configuration of the ultrasonic sonar device 1. The ultrasonic sonar device 1 has a control device 10 inside its main body 5, which is provided with transmitting units 11a, 11b, diodes 12a-12g, receiving units 13a-13g, a filter 14, a detection result image generating means 15, and a display control means 18.

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

[0055] Although not shown in the figure, the control device 10 has a CPU (Central Processing Unit) which is an arithmetic device, a flash memory which is a rewritable non-volatile memory that stores programs executed by the CPU and fixed values ​​referenced by the programs, and / or a ROM (Read Only Memory) which is a non-rewritable non-volatile memory, and a RAM (Random Access Memory) which is a readable and writable volatile memory that temporarily stores various data when the CPU executes a program, and these are connected via a bus line.

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

[0057] The transmission unit 11a generates one drive signal for transmitting ultrasonic waves TB from the first transducers 52a to 52f based on an instruction from the CPU. The output of one drive signal generated by the transmission unit 11a is branched between the transmission unit 11a and the diodes 12a to 12f, and distributed to each of the first transducers 52a to 52f. That is, after branching, one is input to the first transducer 52a via the diode 12a, one is input to the first transducer 52b via the diode 12b, one is input to the first transducer 52c via the diode 12c, one is input to the first transducer 52d via the diode 12d, one is input to the first transducer 52e via the diode 12e, and one is input to the first transducer 52f via the diode 12f.

[0058] The diodes 12a to 12f are elements that pass the drive signals generated by the transmitting unit 11a and input them to the corresponding first oscillators 52a to 52f, and also block the signals (voltages) generated by receiving reflected waves in each of the first oscillators 52a to 52f from being transmitted to the transmitting unit 11a or the branching points of the drive signals output from the transmitting unit 11a to each of the first oscillators 52a to 52f.

[0059] A single drive signal generated by the transmission unit 11a is branched and input to the first transducers 52a-52f via the diodes 12a-12f, so that the first transducers 52a-52f, which have the same shape and size, are driven simultaneously and can output ultrasonic waves TB of the same intensity at the same timing. Therefore, ultrasonic waves TB can be transmitted uniformly in a predetermined direction (i.e., the direction of the first central axes C1a-C1f) included in a predetermined range set in all directions with respect to the ship 71, so that the detection sensitivity can be made uniform in all predetermined directions.

[0060] Furthermore, since one transmission unit 11a is provided for the plurality of first transducers 52a to 52f, it is possible to achieve significant cost reduction and size reduction compared to the case where a transmission unit 11a is provided for each of the first transducers 52a to 52f.

[0061] In addition, the diodes 12a-12f are provided between the transmission unit 11a and each of the first transducers 52a-52f, downstream of the branching point where the drive signal output from the transmission unit 11a branches toward each of the first transducers 52a-52f, so that the signal (voltage) output by each of the first transducers 52a-52f receiving the reflected wave of the ultrasonic wave TB can be prevented from flowing back to the transmission unit 11a or from entering the signal line of the other first transducers 52a-52f via the branching point, causing interference. Therefore, even if one transmission unit 11a is provided for the multiple (six) first transducers 52a-52f, the independence of the signals (voltages) output from each of the first transducers 52a-52f can be ensured.

[0062] The transmission unit 11b corresponds to one of the ultrasonic transmission drive means of the present invention, and generates a drive signal for transmitting ultrasonic waves TB from the second transducer 53 based on an instruction from the CPU. The output of the drive signal generated by the transmission unit 11b is input to the second transducer 53 via the diode 12g. The diode 12g is an element for passing the drive signal generated by the transmission unit 11b and inputting it to the second transducer 53, and for blocking a signal (voltage) generated by receiving a reflected wave at the second transducer 53 so as not to be transmitted to the transmission unit 11b. This diode 12g can suppress the signal (voltage) output by the second transducer 53 by receiving a reflected wave of the ultrasonic wave TB from flowing back to the transmission unit 11b.

[0063] In the ultrasonic sonar device 1, the transmission unit 11b that generates a drive signal for the second transducer 53 that transmits ultrasonic waves TB in the vertical direction directly below the ship 71 is provided separately from the transmission 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 waves TB from the first transducers 52a to 52f and transmitting ultrasonic waves TB only from the second transducer 53, or to control the transmission of ultrasonic waves TB from the second transducer 53 independently of the transmission of ultrasonic waves TB from the first transducers 52a to 52f when performing horizontal detection as a sonar function.

[0064] In this embodiment, the transmission unit 11a corresponding to the first transducers 52a-52f and the transmission unit 11b corresponding to the second transducer 53 are provided separately, but if the specifications of the ultrasonic sonar device 1 are such that the transmission of ultrasonic waves TB from the second transducer 53 can always be performed at the same timing as the first transducers 52a-52f, then only one transmission unit 11a may be provided for the first transducers 52a-52f and the second transducer 53, and one drive signal may be generated from this transmission unit 11a. This allows the ultrasonic sonar device 1 to be further significantly reduced in cost and size.

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

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

[0067] Each of the receiving units 13a to 13g has an amplifier circuit and an analog-to-digital conversion circuit, and as a predetermined process, the received signal (voltage) is amplified by the amplifier 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 a digital signal obtained by an AD conversion circuit as a reception signal received by the first transducer 52a (a reception signal of a reflected wave of the ultrasonic wave TB) to the filter 14. Similarly, the receiving unit 13b outputs a digital signal obtained by each AD conversion circuit as a reception signal of the first transducer 52b, the receiving unit 13c outputs a digital signal obtained by the first transducer 52c, the receiving unit 13d outputs a digital signal obtained by the first transducer 52d, the receiving unit 13e outputs a digital signal obtained by the first transducer 52e, the receiving unit 13f outputs a digital signal obtained by the first transducer 52f, and the receiving unit 13g outputs a digital signal obtained by the second transducer 53 to the filter 14.

[0069] As described above, one transmitting unit 11a is provided for the multiple (six) first transducers 52a-52f to reduce costs and size, whereas receiving units 13a-13f are provided for each of the multiple first transducers 52a-52f, making it possible to perform predetermined processing on each signal (voltage) while maintaining the independence of the signal (voltage) output from each of the first transducers 52a-52f. Meanwhile, since the ultrasonic sonar device 1 is configured with fewer transducers than conventional scanning sonars, even if receiving units 13a-13f are provided for each of the first transducers 52a-52f, the overall receiving unit can be made smaller and costs can be reduced compared to conventional scanning sonars.

[0070] The reception signals output from the reception units 13a to 13g are original reception signals that indicate the raw intensity values ​​of the reflected waves of the ultrasonic waves TB received by the corresponding first transducers 52a to 52f and second transducer 53. The original reception signals are reception signals before filtering by the filter 14, which will be described next.

[0071] The filter 14 performs a predetermined filtering process on the reception signals (original reception signals) output from the reception units 13a to 13g to each of the first transducers 52a to 52f and the second transducer 53. The predetermined filtering process includes spatial filtering and may also include temporal filtering.

[0072] As the spatial filtering process, filtering is performed in the azimuth direction and the distance direction on the original reception signal of each of the first transducers 52a to 52f that receives the reflected wave of the ultrasonic wave TB for each predetermined direction, for the purpose of reducing noise and / or improving the resolution, etc. The spatial filtering process also includes filtering in the distance direction on the original reception signal of the second transducer 53 that receives the reflected wave of the ultrasonic wave TB 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 transducer 52a to first transducer 52f, i.e., the respective acoustic emission directions, are aligned, in other words, the circumferential direction centered on the ship 71. Moreover, the distance direction is the direction in which ultrasonic waves TB are transmitted from the first central axes C1a to C1f of the first transducer 52a to first transducer 52f and the second central axis C2 of the second transducer 53, i.e., the respective acoustic emission directions themselves.

[0074] When performing horizontal detection using the sonar function, the ultrasonic sonar device 1 performs detection using a small number of transducers (six in this embodiment), namely, the first transducers 52a to 52f, and therefore the resolution in the azimuth direction (azimuth resolution) is significantly reduced. On the other hand, the resolution (distance resolution) in the distance direction (direction of the first central axes C1a to C1f) in which the first transducers 52a to 52f transmit and receive ultrasonic waves TB is higher than the azimuth resolution. Therefore, when the detection result image 22 (see FIG. 7) is generated using the original reception signals of the first transducers 52a to 52f as is, a large difference in resolution occurs in the detection result image 22.

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

[0076] The spatial filter process shown in Fig. 6 is roughly classified into three processes. One is to apply a high-pass filter in the azimuth direction to the reception signals obtained from the corresponding first center axes C1a to C1f in the first transducers 52a to 52f (hereinafter, simply referred to as "reception signals of the first center axes C1a to C1f") in the process of S11 to S17, thereby improving the resolution in the azimuth direction. Another is to apply a low-pass filter in the distance direction to the reception signals of the first center axes C1a to C1f in the process of S18, thereby suppressing the resolution in the distance direction. The remaining is to generate reception signals assuming that ultrasonic waves TB are virtually transmitted and received in a virtual direction set between the first center axes C1a to C1f (predetermined direction) in the process of S19 to S28, thereby improving the resolution in the azimuth direction.

[0077] Fig. 6 shows a specific example of a high-pass filter adapted to an azimuth direction in spatial filtering, and a specific example of a method for generating a virtual received signal in a virtual direction. Here, a specific example of spatial filtering will be described with reference to Fig. 6.

[0078] The spatial filtering process is executed when the filter 14 receives the original reception signals of at least the first transducers 52a to 52f from the receiving units 13a to 13f when the ultrasonic sonar device 1 performs horizontal detection using the sonar function.

[0079] When the spatial filter process is started, the filter 14 first performs processes (S11 to S17) for applying a high-pass filter to the reception signals of the first center axes C1a to C1f in the azimuth direction. Specifically, first, an initial value "1" is set to the transducer number i, which is a variable for identifying a transducer (S11). The transducer number i indicates the first transducer 52a when its value is 1, the first transducer 52b when its value is 2, the first transducer 52c when its value is 3, the first transducer 52d when its value is 4, the first transducer 52e when its value is 5, and the first transducer 52f when its value is 6. By setting the transducer number i to 1 in the process of S11, first, a high-pass filter is applied to the original reception signal of the first transducer 52a, and a reception signal after application of the high-pass filter is calculated.

[0080] Next, the filter 14 sets the depth j, which is a variable corresponding to the depth, to an initial value "0" (S12). The depth j, which is a variable corresponding to the depth, is associated with each original reception signal output from the reception units 13a to 13f, and the value of the depth j can be used to determine from which depth the original reception signal represents the intensity level of the reflected wave. By setting the depth j to 0 in the process of S12, first, a high-pass filter is applied to the original reception signal indicating the intensity level of the reflected wave from the shallowest depth detectable by the first transducer 52, and the reception signal after application of the high-pass filter is calculated.

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

[0082]

number

[0083] Here, RX n (j) is the value of the original reception signal corresponding to the depth indicated by the depth j of the first transducer 52 indicated by the transducer number n. in is the influence component rate of the first oscillator 52 indicated by the oscillator number n with respect to the first oscillator 52 indicated by the oscillator number i.

[0084] For example, the reflected wave received by the first transducer 52a includes not only the reflected wave caused by the ultrasonic wave TB transmitted by the first transducer 52a itself, but also the reflected wave caused by the ultrasonic wave TB transmitted by the other first transducers 52b to 52f. This is similar for the first transducers 52b to 52f other than the first transducer 52a, and generally speaking, the first transducer 52 indicated by transducer number i includes not only the reflected wave caused by the ultrasonic wave TB transmitted by itself, but also the reflected wave caused by the ultrasonic wave TB transmitted from the first transducer 52 indicated by transducer number other than i.

[0085] Influence component ratio C in is the ratio of the reflected wave caused by the ultrasonic wave TB transmitted from the first transducer 52 indicated by the transducer number n to the reflected wave received by the first transducer 52 indicated by the transducer number i, and is determined by the installation position (distance), installation angle, and directional characteristics of each first transducer 52. ii is a positive value, and the influence component ratio C of the transducer number n (where n ≠ i) to the first transducer 52 indicated by the transducer number i is in will be negative.

[0086] For the formula (1), the influence component rate C determined above in By using this, as the intensity level of the reflected wave from the depth j in a predetermined direction in which the first transducer 52 indicated by the transducer number i is responsible for detecting the detection target GF (the direction in which the first transducer 52 indicated by the transducer number i transmits and receives the ultrasonic wave TB. In other words, the direction of the first central axis C1a to C1f of the first transducer 52), the intensity level of the reflected wave caused by the ultrasonic wave TB transmitted from the first transducer 52 indicated by the transducer number other than the transducer number i can be removed, and only the intensity level of the reflected wave caused by the ultrasonic wave TB transmitted from the first transducer 52 indicated by the transducer number i can be extracted and used as the received signal in the predetermined direction. As a result, the original received signal RX corresponding to the depth indicated by the depth j of the first transducer 52 indicated by the transducer number i can be obtained. i A high-pass filter is applied to (j) to enhance edges in the azimuth direction, thereby improving the resolution in the azimuth direction.

[0087] After the process of S13, the filter 14 detects whether the depth j is a fixed value j max It is determined whether the fixed value j is less than the threshold (S14). max is the value (maximum value) of depth j indicating the maximum depth at which detection is performed in the first transducer 52 in the direction of the first central axes C1a to C1f.

[0088] As a result of the judgment in S14, the depth j is a fixed value jmax If the depth j is less than the depth j (S14: Yes), the filter 14 adds 1 to the depth j (S15) and returns to the process of S13. As a result, the original received signal RX i The high-pass filter according to the formula (1) is applied to the original reception signal of the first transducer 52 indicated by the transducer number i in the process of S13 (application of the high-pass filter) when the depth j is a fixed value j max That is, for the first transducer 52 indicated by transducer number i, the raw reception signals RX i A high-pass filter is applied to (j).

[0089] As a result of the judgment in S14, the depth j is fixed. max If it is equal to or greater than this (S14: No), then the filter 14 judges whether the transducer number i is less than 6 (S16). If the result of the judgment in S16 is that the transducer number i is less than 6 (S16: Yes), the filter 14 adds 1 to the transducer number i (S17) and returns to the process of S12. Then, the filter 14 executes the processes of S12 to S15 on the original reception signal of the first transducer 52 indicated by the new transducer number i to which 1 has been added.

[0090] As a result, in the first transducer 52 indicated by the new transducer number i to which 1 has been added, the original reception signals RX i A high-pass filter is applied to (j). Then, the original received signal RX from all depths j is i The application of the high-pass filter to (j) is performed for all of the first transducers 52a to 52f by the processes of S16 and S17. If the result of the determination in S16 is that the transducer number i is 6 or more (S16: No), the filter 14 ends the process of applying the high-pass filter to the reception signals of the first center axes C1a to C1f in the azimuth direction, and proceeds to the process of S18.

[0091] In the process of S18, a low-pass filter is applied in the distance direction to the received signal in the direction of each of the first center axes C1a to C1f. The low-pass filter is, for example, a received signal at depth j (here, a received signal R Y after applying a high-pass filter). i This is done by adding (mixing) received signals at previous and subsequent depths (for example, depth (j-1), depth (j+1), etc.) at a predetermined ratio to the first depth (j)). Note that this low-pass filter is just an example, and the method is not limited to this. As a result, a low-pass filter is applied to the received signals in the distance direction for each of the first central axes C1a to C1f of the first transducers 52a to 52f, making the distance direction smooth and suppressing the resolution in the distance direction.

[0092] As described above, in the spatial filtering process, the azimuth resolution is improved and the distance resolution is suppressed for the received signals at the first central axes C1a to C1f of the first transducers 52a to 52f, respectively, so that the azimuth resolution and distance resolution can be harmonized overall.

[0093] Next, after the process of S18, the filter 14 executes a process of generating a reception signal assuming that an ultrasonic wave TB (virtual beam) is virtually transmitted and received in a virtual direction set between the first central axes C1a to C1f (S19 to S28).

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

[0095] However, when the virtual beam number k is "6", (k+1) is 7, and in this case, the transducer number (k+1) indicates transducer number 1. In other words, the virtual beam number 6 indicates a virtual beam in a virtual direction set at the midpoint between the first central axis C1f of the first transducer 52f indicated by transducer number 6 and the first central axis C1a of the first transducer 52a indicated by transducer number 1. This relationship is always satisfied in the processes of S19 to S28.

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

[0097] The filter 14 then calculates the virtual received signal RZ at the depth j of the virtual beam indicated by the virtual beam number k. k In preparation for generating (j), the following formula (2) is used to calculate the reception signal at depth j of the first transducer 52 indicated by transducer number k that sandwiches the virtual beam (here, the reception signal after application of the filter by the processing of S11 to S18. The same applies to the processing of S21 to S24 below). k (j) and the received signal RY at depth j of the first transducer 52 indicated by the transducer number (k+1). k+1 The absolute value DRY of the difference with (j) is calculated (S21).

[0098]

number

[0099] Next, the filter 14 calculates the received signal RY of the first transducer 52 at depth j, which is indicated by the transducer number k, using the following equation (3): k Half of the absolute value DRY of the difference calculated by the process of S21 is subtracted from (j) (S22), and the received signal RY of the first transducer 52 at depth j indicated by the transducer number (k+1) is calculated using the following equation (4). k+1 Half the absolute value DRY of the difference calculated in the process of S21 is subtracted from (j) (S23).

[0100]

number

[0101] The filter 14 also calculates the received signal RY of the first transducer 52 at depth j, which is indicated by the transducer number k, using the following equation (5): k (j) and the received signal RY at depth j of the first transducer 52 indicated by the transducer number (k+1). k+1 (j), and then adding half the absolute value DRY of the difference to the average value, the result is called the virtual received signal RZ at the depth j of the virtual beam indicated by the virtual beam number k. k (j) (S24). Note that the received signal RY at depth j of the first transducer 52 indicated by the transducer number k used in equation (5) is k (j) and the received signal RY at depth j of the first transducer 52 indicated by the transducer number (k+1). k+1 (j) is the value before application of equations (3) and (4).

[0102]

number

[0103] Through the processes in S21 to S24, the filter 14 outputs a virtual received signal RZ at a depth j of a virtual beam indicated by a virtual beam number k. k (j) is the received signal RY of the first transducer 52 at depth j, which is indicated by the transducer number k. k (j) and the received signal RY at depth j of the first transducer 52 indicated by the transducer number (k+1). k+1(j) is generated by applying a filter expressed by equations (2) to (5). As a result, by generating not only reception signals in the directions of the first central axes C1a to C1f in which the first transducer 52 actually transmits and receives the ultrasonic wave TB, but also virtual reception signals in virtual directions located between the first central axes C1a to C1f, the number of directions in which the ultrasonic wave TB is transmitted and received can be increased (in this embodiment, double the number, 12 directions) including the virtual directions, more than the actual number of the first transducers 52 (i.e., the number of predetermined directions). Therefore, the ultrasonic sonar device 1 can improve the azimuth resolution.

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

[0105] Suppose that the virtual received signal RZ at the depth j of the virtual beam is k (j) is the received signal RY of the first transducer 52 at depth j, which is indicated by the transducer number k. k (j) and the received signal RY at depth j of the first transducer 52 indicated by the transducer number (k+1). k+1 If the detection result image 22 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 become greater than the total energy of the reflected waves received by the first transducers 52a to 52f.

[0106] On the other hand, in the process of S21 to S24, a part of the energy (power) is transferred from the actual reception signal of the first transducer 52 to the virtual beam. That is, the filter shown in the formulas (2) to (5) is a filter capable of maintaining the total energy of the reflected waves received by the first transducers 52a to 52f. In this way, a filter capable of maintaining the total energy of the received reflected waves is applied to the reception signal of each of the first transducers 52a to 52f that transmits and receives the ultrasonic waves TB in the direction of the first central axes C1a to C1f, which is a predetermined direction, to generate a reception signal assuming that the ultrasonic waves are virtually transmitted and received in a virtual direction set between the predetermined directions, and even if a virtual reception signal in the virtual direction is generated, it is possible to suppress the total energy in the screen from increasing more than the total energy of the received reflected waves. Therefore, by inserting the reception signal in the virtual direction into the detection result image 22, the ultrasonic sonar device 1 can suppress the detection result image 22 from showing a reaction at a higher level than the actual detection result.

[0107] After the process of S24, the filter 14 determines whether the depth j is equal to the fixed value j. max As a result of the determination in S25, it is determined whether the depth j is less than the fixed value j max If it is less than the threshold (S25: Yes), the filter 14 adds 1 to the 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 the next depth j, and a virtual reception signal RZ at the next depth j of the virtual beam indicated by the virtual beam number k is obtained. k Then, a virtual received signal RZ of the virtual beam indicated by the virtual beam number k is generated. k (j) is the depth j fixed value j max This is repeated until the virtual received signal RZ of the virtual beam indicated by the virtual beam number k is k (j) is generated for all depths j.

[0108] As a result of the judgment of S25, the depth j is fixed maxIf it is equal to or greater than this (S25: No), then filter 14 determines whether virtual beam number k is less than 6 (S27). If the result of the determination in S27 is that virtual beam number k is less than 6 (S27: Yes), filter 14 adds 1 to virtual beam number k (S28) and returns to the process of S20. Then, filter 14 executes the processes of S20 to S26 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 k Then, if the result of the determination in S27 is that the virtual beam number k is 6 or more (S27: No), the virtual received signals RZ k This means that (j) has been generated, so the filter 14 ends the spatial filtering process.

[0110] Returning to Fig. 5, the explanation will be continued. The temporal filtering process in the filter 14 refers to filtering a received signal indicating the intensity of a reflected wave reflected from a certain depth in a certain direction together with at least one received signal received earlier in time from the same direction and the same depth and / or at least one received signal received later in time. This temporal filtering process allows a detection result image 22, which will be described later and is displayed on the display device 21, to be changed smoothly over time, allowing the user to visually recognize the detection result image 22 without any sense of discomfort.

[0111] The filter 14 performs a predetermined filter process on the original reception signals of each of the first transducer 52a to 52f and the second transducer 53, and outputs the values ​​obtained by the filter process as the reception signals of each of the first transducer 52a to 52f and the second transducer 53, and also outputs the virtual reception signals, if any, in a virtual direction to a detection result image generating means 15 described next. The receiving units 13a to 13g and the filter 14 correspond to the reception signal generating means of the present invention.

[0112] The detection result image generating 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. Here, the detection result image 22 will be described with reference to Fig. 7. Fig. 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] 7, the detection result image 22 is a generally known horizontal detection result image, and is a circular display of the latest detection results in each azimuth direction for the omnidirectional detection of the ship 71. Specifically, the latest detection results over a predetermined range set in all azimuth directions of the ship 71 are displayed on the display device 21 as the detection result image 22 based on the reception 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 the virtual reception signals for each direction virtually set between those directions.

[0114] The detection result image generating means 15 shown in Fig. 5 generates a detection result image 22 using the filtered reception signals of the first transducers 52a to 52f input from the filter 14 and virtual reception signals for each virtually set direction. The user can determine in which direction the detection target GF currently exists with respect to the ship 71 by the detection result image 22 (see Fig. 7) displayed on the display device 21.

[0115] 7, a first emission guideline 25 and a second emission guideline 26 are displayed in the detection result image 22. The first emission guideline 25 corresponds to the first line of the present invention, and is a line for indicating a predetermined direction in which the first transducers 52a-52f transmit and receive ultrasonic waves TB, that is, the direction of the first central axes C1a-C1f, in the detection result image 22. The second emission guideline 26 corresponds to the second line of the present invention, and is a line for indicating a virtual direction, which is the transmission and reception direction of a virtual beam in which a virtual reception signal is generated by the filter 14, in the detection result image 22.

[0116] 5, the first radiation guideline 25 and the second radiation guideline 26 are generated by the radiation guideline generating means 15a provided in the detection result image generating means 15. That is, the radiation guideline generating means 15a draws the first radiation guideline 25 in a first manner at a position on the detection result image 22 where the detection result based on the reception signals of the first transducers 52a to 52f is displayed, thereby generating the first radiation guideline 25 on the detection result image 22. Also, the radiation guideline generating means 15a draws the second radiation guideline 26 in a second manner at a position where the detection result based on the virtual reception signals related to the virtual beam generated by the filter 14 is displayed, thereby generating the second radiation guideline 26 on the detection result image 22.

[0117] The first aspect expressing the first radial guideline 25 and the second aspect expressing the second radial guideline 26 are different aspects. The first aspect and the second aspect may have different line types, such as a solid line in the first aspect and a broken line in the second aspect, as shown in FIG. 7, or may have different line colors, such as white in the first aspect and gray in the second aspect. The first aspect may have different line widths, such as a line width of 1 mm and a line width of 0.5 mm in the second aspect. The first aspect may have a low transmittance and the second aspect may have a high transmittance, and the transmittance of each line may be different. Furthermore, the different aspects between the first aspect and the second aspect may be a combination of two or more types of line type, line color, line width, transmittance, etc., and the first aspect and the second aspect may be different by attributes different from these.

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

[0119] Here, the predetermined direction, which is the direction of the first central axes C1a-C1f of the first transducers 52a-52f, has high detection accuracy because the first transducers 52a-52f actually transmit and receive ultrasonic waves TB to detect the detection target GF. On the other hand, the reception signal (detection result) in the virtual direction of the virtual beam set between the first central axes C1a-C1f is generated by interpolating the reception signals of the first transducers 52a-52f, so the detection accuracy is inferior to that of the predetermined direction, which is the direction of the first central axes C1a-C1f of the first transducers 52a-52f.

[0120] The detection result image 22 is generated such that a predetermined direction (the direction of the first central axes C1a to C1f) with high detection accuracy and a virtual direction with poor detection accuracy set between the predetermined direction can be distinguished by the first emission guideline 25 and the second emission guideline 26. This makes it possible to clearly show to the user the virtual direction with poor detection reliability compared to the predetermined direction in which the ultrasonic wave TB was actually transmitted and received, so that the user can check the detection result while taking into account the detection reliability of each direction.

[0121] Furthermore, the detection result image 22 is generated so that the first radiation guideline 25 is displayed in a first manner with respect to the predetermined direction, and the second radiation guideline 26 is displayed in a second manner different from the first manner with respect to the virtual direction. This allows the user to distinguish at a glance from the detection result image 22 between the predetermined direction and the virtual direction in which the detection reliability is low.

[0122] The first emission guideline 25 and the second emission guideline 26 can also be considered as making it possible to determine the reliability of the received signal generated in each direction from the detection result image 22. As a result, in the detection result image 22 in which a predetermined direction with high detection reliability by actual transmission and reception of ultrasonic waves TB and a virtual direction with low detection reliability are mixed, the user can check the detection result while easily grasping the reliability in the detection result image 22.

[0123] Note that the manner in which the reliability of the detection result is represented in the detection result image 22 is not limited to being represented by straight lines such as the first radiating guideline 25 and the second radiating guideline 26, and may be represented by changing the background color of the area in which the detection result is displayed in the detection result image 22. That is, in the detection result image 22, the background color of the position (direction) where the detection result of a predetermined direction with high reliability is displayed and the surrounding area may be different from the background color of the position (direction) where the detection result of a virtual direction with low reliability is displayed and the surrounding area.

[0124] Also, in the detection result image 22, the background color of the position (direction) where the detection result of a predetermined direction with high reliability is displayed may be different from the background color of the position (direction) where the detection result of a virtual direction with low reliability is displayed, and the background color of the area between the predetermined direction and the virtual direction may be interpolated with the colors of both, thereby expressing the background color of the area between the predetermined direction and the virtual direction with a gradation. In this way, in the detection result image 22 where a predetermined direction with high detection reliability and a virtual direction with low detection reliability are mixed by actually transmitting and receiving ultrasonic waves TB, the user can check the detection result while easily grasping the detection reliability of each direction.

[0125] Returning to Fig. 5, the explanation will be continued. The display control means 18 performs control for displaying the detection result image 22 generated by the detection result image generation means 15 and other images on the display device 21. 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 one image on the display device 21.

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

[0127] When a user turns on the power to the ultrasonic sonar device 1 via the operation button 31, or when the power is turned on and an instruction is given to start performing horizontal detection using the sonar function, the ultrasonic sonar device 1 first drives the lifting device 41 to make the transmitting and receiving unit 50 appear underwater from the bottom of the ship 71.

[0128] The ultrasonic sonar device 1 outputs drive signals from the transmission units 11a and 11b, and transmits ultrasonic waves TB in the directions of the first central axes C1a to C1f and the second central axis C2 from the first transducers 52a to 52f and the second transducer 53 of the wave transmitting and receiving unit 50 for a predetermined time. Due to the directional characteristics of the ultrasonic waves TB transmitted from each of the first central axes C1a to C1f, the ultrasonic waves TB are transmitted in all directions to the ship 71.

[0129] The ultrasonic waves TB transmitted from the first transducers 52a-52f and the second transducer 53 are reflected from the detection target GF and the water bottom SB present within a predetermined range from which the ultrasonic waves TB are transmitted. The reflected waves are received by the first transducers 52a-52f and the second transducer 53, and signals (voltages) are output from the first transducers 52a-52f and the second transducer 53 as the intensities of the reflected waves received in the directions of the first central axes C1a-C1f and the second central axis C2, respectively.

[0130] The signals (voltages) output from the first oscillators 52a to 52f and the second oscillator 53 are amplified by the corresponding receiving units 13a to 13g, converted into digital signals (digital values), and output as received signals (original received signals) in each direction of the first center axes C1a to C1f and the second center axis C2.

[0131] These original received signals are subjected to spatial (and temporal) filtering by the filter 14. When the ultrasonic sonar device 1 performs horizontal detection using the sonar function, the filter 14 executes spatial filtering as shown in FIG. 6 as spatial filtering. By this spatial filtering, a high-pass filter is applied in the azimuth direction to the received signals of the first center axes C1a-C1f, improving the resolution in the azimuth direction, which has low resolution, and a low-pass filter is applied in the distance direction, which suppresses the resolution in the distance direction, which has high resolution. This achieves a harmony between the resolution in the azimuth direction and the resolution in the distance direction as a whole.

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

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

[0134] Then, a detection result image 22 in which the latest detection result in each azimuth direction is displayed as a circle for the omnidirectional detection of the ship 71 is generated by the detection result image generating means 15. At this time, the emission guideline generating means 15a generates a first emission guideline 25 representing a predetermined direction in which the first transducers 52a to 52f transmit and receive ultrasonic waves TB, and a second emission guideline 26 representing the transmission and reception direction of a virtual beam in which a virtual reception signal is generated by the filter 14, in the detection result image 22. Then, the detection result image 22 in which the first emission guideline 25 and the second emission guideline 26 are drawn is displayed on the display device 21 by the display control means 18 as shown in FIG.

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

[0136] According to the ultrasonic sonar device 1 configured as above, the transmitting units 11a and 11b drive the wave transmitting and receiving unit 50 so that ultrasonic waves TB are transmitted from the first transducers 52a-52f and the second transducer 53 into the water in all directions relative to the ship 71 set in a predetermined range. Then, the reflected waves of the ultrasonic waves TB reflected from each position in the water for each of the first central axes C1a-C1f and the second central axis C2, which are predetermined directions, are received by the first transducers 52a-52f and the second transducer 53 of the wave transmitting and receiving unit 50, respectively. Based on the reflected waves received by the wave transmitting and receiving unit 50, reception signals are generated for each predetermined direction by the receiving units 13a-13g and the filter 14.

[0137] Based on the generated reception signals for each predetermined direction, a detection result image 22 showing the latest detection result over a predetermined range is generated by the detection result image generating means 15. From this detection result image 22, it is possible to determine at least the presence or absence of a detection target GF within the predetermined range and the direction in which the detection target GF currently exists.

[0138] Here, the first transducers 52a-52f are fixed to the transducer unit 50 so that their first central axes C1a-C1f are in a predetermined direction and are positioned at a predetermined angle θ with respect to the vertical direction when the transducer unit 50 is attached to the ship 71. Each of the first transducers 52a-52f has a predetermined directional characteristic so as to include at least the first central axes C1a-C1f of the adjacent first transducers 52a-52f and the vertical direction. This allows the small number of first transducers 52a-52f to simultaneously transmit ultrasonic waves TB over a predetermined range and receive the reflected waves to detect the detection target GF. Therefore, the ultrasonic sonar device 1 can achieve high-speed detection at low cost.

[0139] In addition, when transmitting and receiving ultrasonic waves TB using a small number of first transducers 52a-52f, the resolution in the azimuth direction may be significantly reduced, but the filter 14 applies a high-pass filter in the azimuth direction to the original reception signal indicating the intensity of the reflected wave in a predetermined direction (the direction of the first central axes C1a-C1f) by each of the first transducers 52a-52f receiving the reflected wave, while applying a low-pass filter in the distance direction to generate a reception signal for each predetermined direction. This improves the resolution in the azimuth direction while suppressing the resolution in the distance direction, so that the resolution in the azimuth direction and the resolution in the distance direction can be harmonised as a whole. Therefore, high-speed detection can be realized at low cost, and the resolution in the azimuth direction and the resolution in the distance direction can be harmonised.

[0140] In addition, by applying a filter capable of maintaining the total energy of the received reflected waves to the received signals for each predetermined direction, the filter 14 generates a received signal assuming that ultrasonic waves are 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, so that the resolution in the azimuth direction can be improved. In addition, since the received signal in the virtual direction is generated in a manner that maintains the total energy of the received reflected waves, it is possible to suppress the total energy in the screen from increasing more than 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 reaction at a higher level than the actual detection result.

[0141] Furthermore, since the first radiation guideline 25 indicating the predetermined direction and the second radiation guideline 26 indicating the virtual direction are displayed in the detection result image 22 generated by the detection result image generating means 15, the user can distinguish between the predetermined direction and the virtual direction in the detection result image 22. This makes it possible to clearly show to the user the virtual direction in which the detection reliability is lower than the predetermined direction in which the ultrasonic waves TB are actually transmitted and received, so that the user can check the detection result while taking into account the detection reliability of each direction.

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

[0143] Although the present invention has been described above based on the embodiments, the present invention is not limited to the above embodiments, and it can be easily assumed that various improvements and modifications are possible within the scope of the present invention. For example, each embodiment may be modified by adding a part or a plurality of parts of the configuration of each other embodiment to the embodiment, or by replacing a part or a plurality of parts of the configuration of the embodiment, including the modified examples described below. In addition, the numerical values ​​given in the above embodiments are merely examples, and other numerical values ​​can be naturally adopted.

[0144] The high-pass filter applied in the azimuth direction to the received signals of the first center axes C1a to C1f in the spatial filtering process shown in FIG. 7 described in the above embodiment (processing of S11 to S17) is one specific example, and the filter applied in the azimuth direction to the received signals of the first center axes C1a to C1f is not limited to the example shown in the above embodiment as long as it is a high-pass filter.

[0145] In the above embodiment, in the spatial filtering process shown in Fig. 7, a high-pass filter is applied to the original received signals of the first center axes C1a to C1f in the azimuth direction first, and then a low-pass filter is applied to the distance direction. However, a low-pass filter may be applied to the original received signals of the first center axes C1a to C1f in the distance direction first, and then a high-pass filter may be applied to the original received signals of the first center axes C1a to C1f. Also, a high-pass filter in the azimuth direction and a low-pass filter in the distance direction may be applied simultaneously to the original received signals of the first center axes C1a to C1f.

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

[0147] In the above embodiment, the case where the second transducer 53 having the second central axis C2 in the vertical direction directly below the ship 71 has been described, but when performing horizontal detection as at least a sonar function, there may be cases where detection in the vertical direction directly below the ship 71 is not necessarily required. In addition, in the above embodiment, since the directional characteristics of the ultrasonic waves TB transmitted from the first transducers 52a to 52f include the vertical direction directly below the ship 71, the detection target GF present in the vertical direction directly below the ship 71 can be detected only by the first transducers 52a to 52f, although the detection sensitivity and / or accuracy is reduced. Therefore, the second transducer 53 may be omitted from the wave transmission and reception unit 50.

[0148] In the above embodiment, the first transducers 52a-52f are inclined with their acoustic radiation surfaces facing inward (towards the side where the second transducer 53 is located), but this is not necessarily limited to the above, and the first transducers 52a-52f may be inclined with their acoustic radiation surfaces facing outward (towards the side opposite to the side where the second transducer 53 is located). In this case, too, it is preferable that each of the first central axes C1a-C1f forms a predetermined angle θ with the second central axis C2 (the vertical direction when the wave transmitting and receiving unit 50 is attached to the ship 71) selected from the range of 20° or more and 50° or less.

[0149] In the above embodiment, the case has been described in which the first transducers 52a to 52f are arranged around the second transducer 53 in the wave transmitting and receiving unit 50. However, the method of arranging the first transducers 52a to 52f and the second transducer 53 in the wave transmitting and receiving unit 50 may be arbitrary, as long as, from a broad perspective, when the wave transmitting and receiving unit 50 is attached to the ship 71, the second central axis C2 is in the vertical direction, the first central axes C1a to C1f form a predetermined angle 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 row or two rows, or the first oscillators 52a to 52f may be arranged in two rows and the second oscillator 53 may be arranged at any position between the two rows of the first oscillators 52a to 52f.

[0150] In the above embodiment, a case has been described in which detection is performed over a predetermined range set in all directions of the ship 71, but the predetermined range may be set in a portion of all directions of the ship 71. In this case, the first range may be set to a portion or the entirety of the predetermined range. Furthermore, the second range may be set to a portion or the entirety of the predetermined range as long as it is different from the first range. [Explanation of symbols]

[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 Filters 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 Guidelines 50 Transmitter / receiver unit 52 First transducer 52a First transducer 52b First transducer 52c 1st transducer 52d First transducer 52e First transducer 52f 1st transducer 53 Second transducer 71 Ship C1a 1st central axis C1b 1st central axis C1c 1st central axis C1d 1st central axis C1e 1st center axis C1f 1st central axis C2 2nd central axis GF Detectable object SB underwater TB ultrasound θ angle

Claims

1. a wave transmitting / receiving unit capable of transmitting ultrasonic waves over a predetermined range underwater and receiving reflected waves of the ultrasonic waves reflected from each position underwater in each predetermined direction; a reception signal generating means for generating a reception signal for each of the predetermined directions based on the reflected wave received by the wave transmitting / receiving unit; a detection result image generating means for generating a detection result image showing the latest detection result over the predetermined range based on the reception signal for each of the predetermined directions generated by the reception signal generating means, The wave transmitting and receiving unit includes: a plurality of first transducers each having a predetermined directional characteristic with respect to a central axis; each of the plurality of first transducers is fixed such that its central axis is in the predetermined direction and is at a predetermined angle with respect to a vertical direction when the wave transmission / reception unit is attached to the ship; and the plurality of first transducers have the predetermined directional characteristics so as to include at least the central axes of adjacent first transducers and the vertical direction; The received signal generating means An ultrasonic sonar device characterized in that a spatial filter is applied to the intensity of the reflected wave obtained for each of the multiple first transducers by receiving the reflected wave, to improve the azimuth resolution and suppress the distance resolution to generate the received signal for each of the specified directions.

2. The received signal generating means 2. The ultrasonic sonar device according to claim 1, further comprising: a filter capable of maintaining the total energy of the received reflected waves applied to the received signals for each of the predetermined directions, thereby generating received signals assuming that ultrasonic waves are virtually transmitted and received in a virtual direction set between the predetermined directions.

3. The detection result image generating means includes:

3. The ultrasonic sonar device according to claim 2, wherein the detection result image is generated so that the predetermined direction and the virtual direction can be distinguished.

4. The detection result image generating means includes:

4. The ultrasonic sonar device according to claim 3, wherein the detection result image is generated so that a first line is represented in a first manner with respect to the specified direction, and a second line is represented in a second manner with respect to the virtual direction that is different from the first manner.

5. The detection result image generating means includes:

3. The ultrasonic sonar device according to claim 2, wherein the detection result image is generated so that the reliability of the received signals generated in each direction can be determined.

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