ultrasonic sonar device

Abstract

The ultrasonic sonar device 1 has a detection result image generating means 17 that generates a horizontal detection result image 22 showing the latest detection result in colors corresponding to the intensity of the reflected waves reflected from each position over a predetermined range, based on the received signals of the reflected waves of ultrasonic waves TB reflected from predetermined directions that include at least a plurality of directions set in the azimuth direction. The detection result image generating means 17 generates the horizontal detection result image 22 by assigning different colors to positions within the predetermined range that are shallower than the depth of the water bottom SB and positions within the predetermined range that are deeper than the depth of the water bottom SB.

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] Ultrasonic sonar devices are known that detect targets, such as schools of fish, over a predetermined underwater range by transmitting and receiving ultrasonic waves. While typical fish finders detect targets in a vertical direction from a ship, ultrasonic sonar devices can detect targets around a ship using horizontal detection, vertical cross-sectional detection, and other methods. Horizontal detection involves detecting targets within a predetermined range, either in all directions or in a partial direction, obliquely downward from the horizontal plane as viewed from the ship. Examples of ultrasonic sonar devices that perform horizontal detection include PPI sonar (searchlight sonar) and scanning sonar.

[0003] PPI sonar emits (transmits) a thin beam of ultrasonic waves and uses a rotatable or pivotable transducer that receives the reflected waves from the object to be detected, and performs underwater detection around the ship while changing the direction of the ultrasonic waves (see, for example, Patent Document 1). PPI sonar can be constructed at low cost because the transducer has a simple structure, but it takes time to complete a single detection over a specified range.

[0004] Scanning sonars form an array of multiple minute transducers on the surface of a cylinder, sphere, or the like, and simultaneously transmit ultrasonic waves from each transducer and receive the reflected waves, thereby performing simultaneous underwater detection around a ship (see, for example, Patent Document 2). While scanning sonars can perform a single detection over a predetermined range in a short time, the transducer array is complex and the transmitting and receiving circuits for transmitting and receiving ultrasonic waves in each transducer are large, making them expensive. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-066208 [Patent Document 2] Japanese Patent Application Publication No. 2019-200204 Summary of the Invention [Problem to be solved by the invention]

[0006] In such an ultrasonic sonar device, the transmitted ultrasonic waves are reflected not only by the detection target but also by the bottom of the water, such as the seabed, and the reflected waves are received. Here, Fig. 13 shows an example of a horizontal detection result image 122 displayed on a display device when a horizontal detection is performed by a conventional ultrasonic sonar device. The horizontal detection result image 122 is a detection result image that shows the detection results of the horizontal detection when the ultrasonic sonar device performs horizontal detection by displaying the intensity of the reflected waves of ultrasonic waves reflected from each position in a color corresponding to that intensity. In the horizontal detection result image 122, the latest underwater detection results in each azimuth direction included in the detection range (predetermined range) are projected onto a plane parallel to the horizontal plane and displayed as a circle centered on the ship's position 172 (or a sector having a central angle at the ship's position 172). As shown in FIG. 13, the horizontal detection result image 122 displays not only the response 122a of the detection target due to the ultrasonic waves reflected from the detection target, but also the response 122b of the water bottom due to the ultrasonic waves reflected from the water bottom.

[0007] A problem with ultrasonic sonar devices is that it is difficult for users to easily distinguish between the response of the detection target and the response of the bottom of the water from the horizontal detection result image 122 displayed in this way. This problem is particularly evident when the detection target is located near the bottom of the water. Furthermore, because the horizontal detection result image 122 projects the detection results onto a plane parallel to the horizontal plane, it is difficult to grasp information about the depth of the location of the response, which makes it even more difficult to distinguish between the response of the detection target and the response of the bottom of the water.

[0008] The present invention has been made to solve the above problems, and aims to provide an ultrasonic sonar device that allows a user to easily identify the object to be detected and / or the bottom of the water. [Means for solving the problem]

[0009] In order to achieve this object, a first aspect of the present invention is an ultrasonic sonar device comprising: a wave transmitting and receiving unit configured at least to transmit ultrasonic waves over a predetermined range underwater and to receive reflected waves of the ultrasonic waves reflected from each position underwater in each predetermined direction including at least a plurality of directions set in the azimuth direction; a received signal generating means for generating a received signal for each of the predetermined directions based on the reflected waves received by the wave transmitting and receiving unit; a detection result image generating means for generating a detection result image showing the latest detection result in a color corresponding to the intensity of the reflected waves reflected from each position over the predetermined range based on the received signals for each of the predetermined directions generated by the received signal generating means; and a water bottom depth determining means for determining the depth of the water bottom based on the intensity of the reflected waves received by the wave transmitting and receiving unit, wherein the detection result image generating means generates the detection result image by assigning different colors to positions within the predetermined range that are shallower than the depth of the water bottom and to positions within the predetermined range that are deeper than the depth of the water bottom.

[0010] A second aspect of the present invention is an ultrasonic sonar device according to the first aspect, wherein the detection result image generating means generates the detection result image by differentiating at least the brightness, saturation, hue, or transparency between a color assigned to a position within the specified range that is shallower than the depth of the water bottom and a color assigned to a position within the specified range that is deeper than the depth of the water bottom.

[0011] A third aspect of the present invention is an ultrasonic sonar device according to the first or second aspect, wherein the detection result image generation means first generates the detection result image over the specified range in a color assigned to positions shallower than the depth of the water bottom, and then overwrites pixels in the generated detection result image at positions deeper than the depth of the water bottom with the color assigned to positions deeper than the depth of the water bottom, and displays the overwritten detection result image.

[0012] A fourth aspect of the present invention is an ultrasonic sonar device according to the first or second aspect, further comprising a storage means for storing the reception signals generated by the reception signal generating means for each of the predetermined directions in association with polar coordinates indicated by information corresponding to the direction and information corresponding to the distance to a position where a reflected wave of the ultrasonic wave that is the source of the reception signal has been generated, and the detection result image generating means specifies each pixel of the detection result image by orthogonal coordinates, and includes a conversion table that associates the corresponding polar coordinates with the distance from the wave transmitting and receiving unit at a position in the water corresponding to the pixel for the orthogonal coordinates of each pixel, and For each pixel in the detection result image, the intensity of the reflected wave from the underwater position corresponding to that pixel is identified based on the received signal stored in the memory means and associated with polar coordinates corresponding to the pixel's Cartesian coordinates identified by the conversion table, and a determination is made as to whether the pixel is located shallower or deeper than the depth of the water bottom based on the distance from the transmitting and receiving unit to the underwater position corresponding to the pixel identified by the conversion table, and the detection result image is generated while assigning different colors to the intensity of the reflected wave from the underwater position corresponding to the identified pixel based on the result of the determination.

[0013] A fifth aspect of the present invention is an ultrasonic sonar device according to the fourth aspect, wherein the detection result image generating means comprises a first palette that defines colors to be assigned to the intensity of reflected waves, and a second palette that defines colors to be assigned to the intensity of reflected waves that are different from the colors defined in the first palette, and for each pixel of the detection result image, a color is assigned to the intensity of the reflected waves from the underwater position corresponding to the identified pixel based on the distance from the transmitting and receiving unit to the underwater position corresponding to the pixel identified by the conversion table, using the first palette if the pixel is located shallower than the depth of the bottom of the water, and using the second palette if the pixel is located deeper than the depth of the bottom of the water.

[0014] A sixth aspect of the present invention is an ultrasonic sonar device according to any one of the first to fifth aspects, wherein the transmitting and receiving unit comprises a plurality of first transducers having a predetermined directional characteristic, each of which is fixed so that its central axis is in the predetermined direction and is at a predetermined angle relative to the vertical direction when the transmitting and receiving unit is attached to a ship, and which has the predetermined directional characteristic so as to include at least the central axes of adjacent first transducers and the vertical direction.

[0015] A seventh aspect of the present invention is an ultrasonic sonar device according to the sixth aspect, wherein the transmitting and receiving unit further has a second transducer fixed so that its central axis is positioned vertically when attached to a ship.

[0016] An eighth aspect of the present invention is an ultrasonic sonar device according to the seventh aspect, wherein the bottom depth determination means determines the depth of the bottom in the vertical direction based on the intensity of the reflected wave received by the second transducer after the ultrasonic wave is transmitted by the second transducer. [Effects of the Invention]

[0017] According to the ultrasonic sonar device of the first aspect of the present invention, a wave transmitting / receiving unit transmits ultrasonic waves into water over a predetermined range, and receives reflected waves of the ultrasonic waves reflected from various positions underwater in each predetermined direction, including at least a plurality of directions set in the azimuth direction. A received signal generating means generates a received signal for each predetermined direction based on the reflected waves received by the wave transmitting / receiving unit. A detection result image generating means generates a detection result image showing the latest detection result in a color corresponding to the intensity of the reflected waves reflected from various positions over the predetermined range based on the received signals for each predetermined direction generated by the received signal generating means. From this detection result image, a user can determine whether a detection target is present, as well as the direction and horizontal distance of the detection target.

[0018] Here, the depth of the water bottom is determined by the water bottom depth determination means based on the intensity of the reflected waves received by the wave transmitting / receiving unit.Then, the detection result image generation means generates a detection result image by assigning different colors to positions within a predetermined range that are shallower than the water bottom and to positions within a predetermined range that are deeper than the water bottom.This allows the user to easily determine from the colors displayed in the detection result image whether the reaction displayed in the detection result image is a reaction from the detection target or a reaction from the water bottom.This has the effect of allowing the user to easily distinguish between the detection target and / or the water bottom.

[0019] The ultrasonic sonar device according to the second aspect achieves the following effect in addition to the effect achieved by the ultrasonic sonar device according to the first aspect. That is, the detection result image generation means generates a detection result image so that the color assigned to positions within a predetermined range that are shallower than the depth of the water bottom differs from the color assigned to positions deeper than the depth of the water bottom in at least brightness, saturation, hue, or transparency. This makes it possible to clearly differentiate the color assigned to responses from the detection target and the color assigned to responses from the water bottom in the detection result image. This has the effect of allowing the user to easily distinguish between the detection target and / or the water bottom.

[0020] The ultrasonic sonar device according to the third aspect achieves the following effect in addition to the effects achieved by the ultrasonic sonar device according to the first or second aspect. That is, the detection result image generating means first generates a detection result image covering a predetermined range in a color assigned to positions shallower than the depth of the water bottom. Then, the detection result image generating means overwrites pixels in the generated detection result image that are deeper than the depth of the water bottom with the color assigned to positions deeper than the depth of the water bottom. The overwritten detection result image is displayed. This allows the process of generating the detection result image to be executed with a simple program structure, resulting in the effect of generating a detection result image that allows the user to easily distinguish the detection target and / or the water bottom while keeping the memory capacity required for the program small.

[0021] The ultrasonic sonar device according to the fourth aspect achieves the following effect in addition to the effect achieved by the ultrasonic sonar device according to the first or second aspect. Specifically, the received signals generated by the received signal generating means for each predetermined direction are stored in the storage means in association with polar coordinates indicated by information corresponding to the direction and information corresponding to the distance to the location where the reflected ultrasonic waves that are the basis of the received signals were generated. Meanwhile, the detection result image generating means identifies each pixel of the detection result image using Cartesian coordinates. The detection result image generating means also has a conversion table that associates the polar coordinates with the Cartesian coordinates of each pixel. This conversion table also associates the Cartesian coordinates of each pixel with the distance from the wave transmitting / receiving unit at the underwater location corresponding to the pixel indicated by the Cartesian coordinates. The detection result image generating means then identifies, for each pixel of the detection result image, the intensity of the reflected waves from the underwater location corresponding to that pixel based on the received signals stored in the storage means in association with the polar coordinates corresponding to the Cartesian coordinates of the pixel identified by the conversion table. Furthermore, the detection result image generating means determines whether the pixel is located shallower or deeper than the water bottom based on the distance from the wave transmitting / receiving unit to the underwater position corresponding to the pixel specified by the conversion table, and generates a detection result image based on the result of that determination, assigning different colors to the intensity of the reflected wave from the underwater position corresponding to the specified pixel. This makes it possible to generate a detection result image by performing a single coordinate conversion process using the conversion table, assigning different colors to positions within a predetermined range that are shallower than the water bottom and to assign different colors to positions within a predetermined range that are deeper than the water bottom. This has the effect of reducing the time required to generate the detection result image while generating a detection result image that allows the user to easily distinguish the detection target and / or the water bottom.

[0022] The ultrasonic sonar device according to the fifth aspect achieves the following effect in addition to the effect achieved by the ultrasonic sonar device according to the fourth aspect. That is, the detection result image generation means has a first palette that defines colors to be assigned to the intensity of reflected waves, and a second palette that defines colors to be assigned to the intensity of reflected waves that are different from the colors defined in the first palette. Then, for each pixel of the detection result image, the detection result image generation means assigns a color to the intensity of the reflected waves from the underwater position corresponding to the identified pixel based on the distance from the wave transmitting and receiving unit to the identified underwater position corresponding to the pixel, using the first palette if the pixel is located shallower than the bottom of the water, and using the second palette if the pixel is located deeper than the bottom of the water. As a result, by simply changing the palette used based on the distance from the wave transmitting / receiving unit to the underwater position corresponding to the pixel in a single coordinate conversion process using the conversion table, it is possible to generate a detection result image by assigning different colors to positions within a predetermined range that are shallower than the depth of the water bottom and different colors to positions within a predetermined range that are deeper than the depth of the water bottom.This has the effect of reducing the time required to generate a detection result image while easily generating a detection result image that allows the user to easily distinguish the detection target and / or the water bottom.

[0023] The ultrasonic sonar device according to the sixth aspect achieves the following effect in addition to the effect achieved by the ultrasonic sonar device according to any one of the first to fifth aspects. Specifically, the 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 relative to the vertical direction when the transducer unit is attached to the vessel. Each first transducer has a predetermined directional characteristic that includes at least the central axis of an 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 a detection target. Therefore, an ultrasonic sonar device capable of high-speed detection can be constructed at low cost. Here, since the first transducer has a directional characteristic in the vertical direction, it receives reflected waves from the water bottom in the vertical direction before receiving reflected waves from the water bottom in the direction of its own central axis. If the same color is assigned to the reaction from the detection target and the reaction from the bottom of the water in the detection result image, it is difficult to grasp the reaction from the bottom of the water in the vertical direction. In contrast, the detection result image generation means generates a detection result image by assigning different colors to positions within a predetermined range that are shallower than the depth of the bottom of the water and to positions within a predetermined range that are deeper than the depth of the bottom of the water, which has the effect of allowing the user to easily determine the reaction from the bottom of the water in the vertical direction in the detection result image.

[0024] The ultrasonic sonar device according to the seventh aspect achieves the following effect in addition to the effect achieved by the ultrasonic sonar device according to the sixth aspect. That is, in addition to the first transducer, the wave transmitting and receiving unit is provided with a second transducer fixed so that its central axis is positioned in the vertical direction when the wave transmitting and receiving unit is attached to a ship. This has the effect of enabling detection of a detection target in the vertical direction and / or measurement of depth in the vertical direction to be performed with high accuracy.

[0025] The ultrasonic sonar device according to the eighth aspect achieves the following effect in addition to the effect achieved by the ultrasonic sonar device according to the seventh aspect. Specifically, ultrasonic waves are transmitted from a second transducer whose central axis is positioned in the vertical direction, and the water bottom depth determination means determines the water bottom depth in the vertical direction based on the intensity of the reflected waves received by the second transducer. This allows the water bottom depth in the vertical direction to be determined with greater accuracy than when the water bottom depth in the vertical direction is determined using a first transducer whose central axis is positioned at a predetermined angle with respect to the vertical direction. This has the effect of clearly indicating to the user in the detection result image the response from the water bottom depth in the vertical direction with high accuracy. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a schematic diagram illustrating the configuration of an ultrasonic sonar device according to a first embodiment of the present invention. [Figure 2] 1 is a schematic side view showing a state in which underwater detection is performed by a ship equipped with the ultrasonic sonar device. FIG. [Figure 3] 1A is a schematic cross-sectional view showing the wave transmitting and receiving unit of the ultrasonic sonar device, and FIG. 1B is a schematic perspective view showing the arrangement of a plurality of first transducers and second transducers that make up 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 the ultrasound transmitted from the first transducer, and (d) is a diagram showing the directional characteristics of the ultrasound transmitted from the first transducer when viewed from the front side of the ship. [Figure 5] 10 is a diagram showing an example of a display screen displayed on a display device when the ultrasonic sonar device performs horizontal detection as a sonar function. FIG. [Figure 6] FIG. 2 is a block diagram showing the electrical configuration of the ultrasonic sonar device. [Figure 7] 3 is a diagram showing a schematic diagram of the contents of a received signal array stored in a storage means of the ultrasonic sonar device. FIG. [Figure 8] 3 is a schematic diagram showing an example of a first palette and a second palette included in the detection image generating means of the ultrasonic sonar device. FIG. [Figure 9] 10 is a flowchart showing a horizontal detection result image generation process executed by the detection image generation means. [Figure 10] FIG. 10 is a block diagram showing the electrical configuration of an ultrasonic sonar device according to a second embodiment of the present invention. [Figure 11] 3 is a diagram schematically showing a conversion table included in the detection result image generating means of the ultrasonic sonar device. FIG. [Figure 12] 10 is a flowchart showing a horizontal detection result image generation process executed by the detection image generation means. [Figure 13] FIG. 10 is a diagram showing an example of a horizontal detection result image displayed on a display device when horizontal detection is performed in a conventional ultrasonic sonar device. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Each of the embodiments described below illustrates a preferred specific example of the present invention. Therefore, the numerical values, shapes, materials, components, component placement and connection configurations, etc., shown in the following embodiments are merely examples and are not intended to limit the present invention. Therefore, among the components in the following embodiments, components that are not recited in the independent claims that represent the highest concept of the present invention will be described as optional components. Furthermore, in each drawing, substantially identical components are assigned the same reference numerals, and redundant explanations will be omitted or simplified.

[0028] (First embodiment) First, an ultrasonic sonar device 1 according to a first embodiment, which is one embodiment of the present invention, will be described with reference to Figures 1 to 9. 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 vessel 71 equipped with the ultrasonic sonar device 1 performing underwater detection.

[0029] 1 and 2, the ultrasonic sonar device 1 is mounted on a ship 71 and has at least a sonar function for horizontally detecting a detection target GF, such as a school of fish, over a predetermined range around the ship 71 in the waters of the sea, lake, river, or other area on which the ship 71 floats. Horizontal detection is performed by detecting a detection target GF within a predetermined range that is diagonally downward from the horizontal plane as viewed from the ship 71 and in all directions in the azimuth direction.

[0030] In this embodiment, a case will be described in which the predetermined range in which horizontal detection is performed is all-directional in the azimuth direction as viewed from the ship 71, but it does not necessarily have to be all-directional, and it may be in a partial direction in the azimuth direction as viewed from the ship 71. Furthermore, the ultrasonic sonar device 1 may have a sonar function that performs vertical cross-sectional detection in addition to horizontal detection, and may also have a fish detection function that detects detection targets GF that exist in the vertical direction directly below the ship 71 and displays the detection results in a chronological order.

[0031] The ultrasonic sonar device 1 includes a main body 5, an operation button 31 provided on the main body 5, a display device 21 as display means 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 an elevator 41 that raises and lowers the wave transmission / reception unit 50. The main body 5, operation button 31, and display device 21 are disposed in the wheelhouse of the ship 71, while the wave transmission / reception unit 50 and the elevator 41 are disposed in the bottom of the ship 71. The wave transmission / reception unit 50 is raised and lowered by the elevator 41, so that it can freely appear and disappear underwater from the bottom of the ship 71. Note that the ultrasonic sonar device 1 does not necessarily have to include the elevator 41, and the wave transmission / reception unit 50 may be fixed to the ship 71 in a position where it can transmit and receive ultrasonic waves TB into the water.

[0032] 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 power of the ultrasonic sonar device 1 on / off, set the detection mode (horizontal detection, vertical cross-sectional detection, fish detection, etc.) and detection range of the ultrasonic sonar device 1, set the type and brightness of the image displayed by the display device 21, etc.

[0033] 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 within the predetermined cone-shaped range, the bottom of the sea or lake (hereinafter collectively referred to as the "bottom SB"), etc. The detailed configuration of the wave transmitting and receiving unit 50 will be described later with reference to FIGS. 3 and 4.

[0034] The display device 21 displays the detection result based on the received signal generated by receiving units 13a to 13g (described later) and a filter 14 (see FIG. 5) when the wave transmitting and receiving unit 50 receives the reflected wave of the ultrasonic wave TB. The display device 21 is configured, for example, with a liquid crystal display or an organic EL (Electro-Luminescence) display. When the ultrasonic sonar device 1 performs horizontal detection using the search function, a horizontal detection result image 22 is displayed on the display device 21 as a detection result image. Details of the horizontal detection result image 22 will be described later with reference to FIG. 5.

[0035] Next, the 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 the arrangement of a plurality of first vibrators 52 (52a to 52f) and a second vibrator 53 that constitute the wave transmitting and receiving unit 50.

[0036] 4(a) is a diagram schematically showing the first center axes C1a to C1f of the first transducers 52a to 52f when viewed vertically from above the ship 71, and FIG. 4(b) is a diagram schematically showing the first center axes C1a to C1f of the first transducers 52a to 52f when viewed horizontally from the front side of the ship 71. FIG. 4(c) is a diagram schematically showing directional characteristics E1a, E1b, and E1f of ultrasonic waves TB transmitted from adjacent first transducers 52a, 52b, and 52f, and FIG. 4(d) is a diagram showing directional characteristics E1a and E1d of ultrasonic waves TB transmitted from the first transducers 52a and 52d, respectively, when viewed from the front side of the ship 71.

[0037] 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 oscillators 52 (first oscillator 52a, first oscillator 52b, first oscillator 52c, first oscillator 52d, first oscillator 52e, and first oscillator 52f) that transmit ultrasonic waves TB in a predetermined direction and receive the reflected waves, and a second oscillator 53 are housed and molded in a case 51. The individual first oscillators 52 are disk-shaped structures having the same size and shape. Similarly to the first oscillators 52, the second oscillators 53 also have a disk-like shape. However, the size of the second oscillators 53 is determined according to the desired characteristics. That is, the second oscillators 53 may be the same size as the first oscillators 52, or may be a different size from the first oscillators 52.

[0038] Each of the first vibrator 52 and the second vibrator 53 includes a base material 54 and a piezoelectric element 55. The base material 54 is a circular resin plate material that also serves as an acoustic matching layer, and is made of, for example, glass epoxy.

[0039] The piezoelectric element 55 is a plate-like object made of piezoelectric ceramic, 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 substrate 54 via an adhesive layer (not shown), and a back electrode (not shown) formed on its back surface opposite the front surface. Lead wires are electrically connected to the front electrode and the back electrode, respectively.

[0040] When a drive voltage is applied to the piezoelectric element 55 by a front electrode and a back electrode from the transmitting unit 11a or the transmitting unit 11b (see FIG. 5), which will be described later, the piezoelectric element 55 deforms in the thickness direction and vibrates the base material 54. This vibration of the base material 54 causes the first vibrator 52 and the second vibrator 53 to generate ultrasonic waves TB.

[0041] Furthermore, when the substrate 54 of each of the first oscillator 52 and the second oscillator 53 is vibrated by the reflected waves of the ultrasonic waves TB, the vibrations deform the piezoelectric element 55, generating a voltage between the front electrode and the back electrode. The first oscillators 52a to 52f and the second oscillator 53 output the voltage generated between the front electrode and the back electrode to the corresponding receiving units 13a to 13g, which will be described later, thereby generating reception signals corresponding to the reflected waves received by each of the first oscillators 52a to 52f and the second oscillator 53.

[0042] The case 51 has an opening at one end, and houses a plurality of first vibrators 52 and second vibrators 53 inside the case 51. The second vibrator 53 is disposed at the center of the case 51. Six first vibrators 52 are disposed around the second vibrator 53 in the order of first vibrator 52a, first vibrator 52b, first vibrator 52c, first vibrator 52d, first vibrator 52e, and first vibrator 52f, in a counterclockwise direction as viewed from the front surface of the base material 54. The acoustic radiation surfaces formed on the front surface of the base material 54 of each of the first vibrators 52 and the acoustic radiation surface formed on the front surface of the base material 54 of the second vibrator 53 are all located on a single imaginary spherical surface.

[0043] In this embodiment, the number of first oscillators 52 is six, but the number of first oscillators 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 oscillators 52 is large, the configuration of the ultrasonic sonar device 1 becomes complicated, larger, and more expensive, so the number of first oscillators 52 is preferably ten or less, and more preferably eight or less.

[0044] Here, the direction of the first oscillator 52a's first central axis C1a (which can also be considered the direction of the normal vector of the first oscillator 52a) is the central axis that is perpendicular to the center of the front surface (sound radiation surface) of the base material 54. Similarly to the first oscillator 52a, the first oscillator 52b is defined as having a first central axis C1b, the first oscillator 52c as having a first central axis C1c, the first oscillator 52d as having a first central axis C1d, the first oscillator 52e as having a first central axis C1e, and the first oscillator 52f as having a first central axis C1f. The first central axes C1b to C1f can be understood to be the sound radiation directions of the corresponding first oscillators 52b to 52f.

[0045] Furthermore, the direction of the second central axis C2 (which can also be said to be the direction of the normal vector of the second oscillator 53), which is a central axis perpendicular to the center of the front surface (acoustic radiation surface) of the base material 54, can be understood to be the acoustic radiation direction of the second oscillator 53.

[0046] That is, the first central axes C1a to C1f of the first oscillators 52a to 52f and the second central axis C2 of the second oscillator 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.

[0047] Here, the wave transmitting / receiving unit 50 is attached to the vessel 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 (radiates) ultrasonic waves TB in the vertical direction directly below the vessel 71. The presence of this second transducer 53 enables the ultrasonic sonar device 1 to detect the detection target GF in the vertical direction and / or measure the depth of the water bottom SB in the vertical direction with high accuracy. Note that the directional characteristics of the ultrasonic waves TB transmitted from the second transducer 53 are preferably a narrow beam with a small beam angle. This further increases the accuracy of detecting the detection target GF in the vertical direction and measuring the depth of the water bottom SB in the vertical direction.

[0048] 3, in the wave transmitting and receiving unit 50, the first transducers 52a to 52f are arranged with the sound emitting surface of each of the first transducers 52a to 52f inclined such that the first central axes C1a to C1f form a predetermined angle ω 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 a result, the sound emitting direction of each of the first transducers 52a to 52f is oriented in a direction different from the vertical direction directly below the ship 71, as shown in FIG. 4(b).

[0049] In this embodiment, the first transducers 52a to 52f are tilted with their acoustic radiation surfaces facing inward (toward the second transducer 53) (see FIG. 3). Preferably, each of the first central axes C1a to C1f forms a predetermined angle ω with respect to the second central axis C2, the predetermined angle ω being an angle selected from the range of 20° to 50°. In this embodiment, the predetermined angle ω is 30°. As shown in FIG. 3(a), the first central axes C1a to C1f and the second central axis C2 converge at one point.

[0050] 4(a), when the wave transmitting and receiving unit 50 is attached to the ship 71 and viewed vertically from above the ship 71, the first center axes C1a to C1f of the first oscillators 52a to 52f are arranged at equal intervals in the azimuth direction so that the angles formed between adjacent first center axes C1a to C1f are the same angle δ. When the number of first oscillators 52 is n, the angle δ is (360 / n)° (when the number of first oscillators 52 is six, the angle δ is 60°).

[0051] As a result, the transmitting and receiving unit 50 can simultaneously transmit ultrasonic waves TB in each of the predetermined directions indicated by the first center 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.

[0052] 4(a) and 4(b), when the ship 71 is viewed vertically from above, the wave transmitting and receiving unit 50 is attached to the ship 71 so that the first central axis C1a faces rightward with respect to the longitudinal direction of the ship 71 and the first central axes C1b to C1f are aligned counterclockwise from the first central axis C1a at intervals of an angle δ. In addition, in this 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 ultrasonic waves TB can be simultaneously transmitted by at least the first transducers 52a to 52f 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. The directions of the first central axes C1a to C1f set as above correspond to the "plurality of directions set in the azimuth directions" of the present invention.

[0053] 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 characteristic E1a of the ultrasonic waves TB transmitted from the first transducer 52a is 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.

[0054] On the other hand, both the directional characteristic E1b of the ultrasonic waves TB transmitted from the first transducer 52b and the directional characteristic E1f of the ultrasonic waves TB transmitted from the first transducer 52f are set to include the first central axis C1a of the first transducer 52a. Although not shown, the directional characteristic E1b of the ultrasonic waves TB transmitted from the first transducer 52b is also set to include the first central axis C1c of the first transducer 52c that is adjacent to the first transducer 52a on the opposite side, and the directional characteristic E1f of the ultrasonic waves TB transmitted from the first transducer 52f is also set to include the first central axis C1e of the first transducer 52e that is adjacent to the first transducer 52a on the opposite side.

[0055] 4(d), the directional characteristic E1a of the ultrasonic waves TB transmitted from the first transducer 52a and the directional characteristic E1d of the ultrasonic waves TB transmitted from the first transducer 52d both include the vertical direction when the wave transmission and reception unit 50 is attached to the ship 71. Although not shown, the directional characteristics of the ultrasonic waves TB transmitted from the first transducers 52b, 52c, 52e, and 52f are also set to include the vertical direction when the wave transmission and reception unit 50 is attached to the ship 71, similar to the first transducers 52a and 52d.

[0056] As described above, the directivity of the ultrasonic waves TB transmitted from each of the first transducers 52a to 52f is set so as to include the first central axes C1a to C1f of the adjacent first transducers 52 and also 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 to 52f, the transducer unit 50 irradiates ultrasonic waves TB from each of the first transducers 52a to 52f in the direction of the respective first central axes C1a to 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.

[0057] Furthermore, the directions of the first central axes C1a to C1f of the first transducers 52a to 52f and the directional characteristics of the ultrasonic waves TB emitted from the first transducers 52a to 52f are fixed so that the ultrasonic waves TB are emitted over a predetermined range from the wave transmitting and receiving unit 50. This eliminates the need for circuits for controlling the directions of the first central axes C1a to C1f of the first transducers 52a to 52f and circuits for controlling the directional characteristics of the ultrasonic waves TB emitted from the first transducers 52a to 52f.

[0058] The wave transmitting and 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 oscillators 52a to 52f corresponding to each of the first center axes C1a to 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 and at low cost.

[0059] 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 spaced so that the first central axes C1a-C1f and the second central axis C2 are oriented in the above-mentioned directions, and is fixed in place by a filler. This filler is made of a waterproof resin material (such as urethane resin) that has a lower specific acoustic impedance than the base material 54, which is the acoustic matching layer for the first transducers 52 and the second transducers 53. The filler is filled so that the outer surface is flush with the opening of the case 51, thereby sealing the opening of the case 51.

[0060] Next, the horizontal detection result image 22 will be described with reference to Fig. 5. Fig. 5 is a diagram that schematically shows an example of a display screen that is displayed on the display device 21 when the ultrasonic sonar device 1 performs horizontal detection as a sonar function.

[0061] As shown in Fig. 5, when the ultrasonic sonar device 1 performs horizontal detection as a sonar device, it primarily displays a horizontal detection result image 22 on the display device 21. Note that when performing horizontal detection, the ultrasonic sonar device 1 may also display, in addition to the horizontal detection result image 22, one or more detection result images on the display device 21 that chronologically arrange detection results in the distance direction from the wave transmitting and receiving unit 50 based on received signals in at least one direction (in the example of Fig. 5, this corresponds to each of the two detection result images displayed one above the other in the left-hand area of ​​the display device 21). Furthermore, detection result images other than the horizontal detection result image 22 may be displayed or hidden on the display device 21 by the user operating the operation button 31.

[0062] The horizontal detection result image 22 is a detection result image that shows the latest detection results in colors corresponding to the intensity of reflected waves of ultrasonic waves TB reflected from each position over a predetermined range, which is the detection range, in response to horizontal detection performed in all directions (or some of the directions) diagonally downward from the ship 71. In the horizontal detection result image 22, the latest underwater detection results in each direction included in the predetermined range are displayed as a circle (or a sector having a central angle at the position 72 of the ship 71) projected onto a plane parallel to the horizontal plane, with the position 72 of the ship 71 at its center. Specifically, based on the received signals for each direction of the first central axes C1a to C1f of the first transducers 52a to 52f, the latest underwater detection results over a predetermined range set in all directions of the ship 71 (hereinafter also referred to as "underwater detection results projected onto a plane parallel to the horizontal plane") are displayed on the display device 21 as the horizontal detection result image 22 projected onto a plane parallel to the horizontal plane.

[0063] As described above, when ultrasonic waves TB are transmitted from the wave transmitting / receiving unit 50 over a predetermined range, the ultrasonic waves TB are reflected from detection targets GF included in that predetermined range. A response 22a based on the waves reflected from the detection targets GF (hereinafter referred to as the "response 22a of the detection target GF") is displayed in the horizontal detection result image 22. The ultrasonic waves TB are also reflected from the water bottom SB, and a response 22b based on the waves reflected from the water bottom SB (hereinafter referred to as the "response 22b of the water bottom SB") is also displayed in the horizontal detection result image 22.

[0064] Here, when generating the horizontal detection result image 22, the ultrasonic sonar device 1 according to this embodiment assigns different colors depending on the intensity of the waves reflected from the detection target GF (colors defined in a first palette 17a, described later) and different colors depending on the intensity of the waves reflected from the water bottom SB (colors defined in a second palette 17b, described later). For example, this allows the user of the ultrasonic sonar device 1 to easily determine, from the color displayed in the horizontal detection result image 22, whether the response displayed in that horizontal detection result image 22 is the response 22a of the detection target GF or the response 22b of the water bottom SB. Therefore, the user can easily distinguish between the detection target GF and / or the water bottom SB.

[0065] In this case, for example, the color assigned in accordance with the intensity of the wave reflected from the detection target GF may be a bright color, and the color assigned in accordance with the intensity of the wave reflected from the water bottom SB may be a dark color.Alternatively, the color assigned in accordance with the intensity of the wave reflected from the detection target GF may be a highly saturated color, and the color assigned in accordance with the intensity of the wave reflected from the water bottom SB may be a less saturated color.Alternatively, the color assigned in accordance with the intensity of the wave reflected from the detection target GF may be a color with low transparency (transparency), and the color assigned in accordance with the intensity of the wave reflected from the water bottom SB may be a color with high transparency (transparency).

[0066] This allows the color assigned to the reaction 22a of the detection target GF to be clearly different from the color assigned to the reaction 22b of the bottom SB, and also allows the reaction 22a of the detection target GF to be emphasized and conveyed to the user, making it easier to draw the user's attention to the reaction 22b of the detection target GF.

[0067] The relationship of brightness, saturation, or transparency (transparency) between the color assigned according to the intensity of the reflected wave from the detection target GF and the color assigned according to the intensity of the reflected wave from the water bottom SB may be reversed. This also makes it possible to clearly differentiate the color assigned to the reaction 22a of the detection target GF from the color assigned to the reaction 22b of the water bottom SB, and to emphasize the reaction 22b of the water bottom SB and convey it to the user, thereby more clearly drawing the user's attention to the water bottom SB.

[0068] Furthermore, the color assigned according to the intensity of the wave reflected from the detection target GF may be different from the color assigned according to the intensity of the wave reflected from the water bottom SB. This also makes it possible to clearly differentiate the color assigned to the reaction 22a of the detection target GF from the color assigned to the reaction 22b of the water bottom SB.

[0069] Furthermore, the user may be able to set whether to assign different colors depending on the intensity of the reflected waves from the detection target GF and the intensity of the reflected waves from the water bottom SB by operating the operation button 31. This allows the ultrasonic sonar device 1 to allow the user to select whether to display the response 22a of the detection target GF and the response 22b of the water bottom SB in different colors in the horizontal detection result image 22.

[0070] The determination of whether the reflected wave of the received ultrasonic wave TB is due to reflection from the detection target GF or from the water bottom SB is made based on the distance from the transmitting / receiving unit 50 to the position where the reflection of the reflected wave of the ultrasonic wave TB occurred and the depth of the water bottom SB determined by the water bottom depth determination means 16 described later.

[0071] The distance to the position where the reflected wave of the ultrasonic wave TB is reflected can be determined based on the elapsed time from when the wave transmitting / receiving unit 50 transmits the ultrasonic wave TB until it receives the reflected wave of the ultrasonic wave TB. The depth of the water bottom SB can be determined based on the intensity of the reflected wave of the ultrasonic wave TB, as will be described later in the explanation of the water bottom depth determination means 16.

[0072] If the distance to the position where the reflected wave of the ultrasonic wave TB is reflected is less than the depth of the water bottom SB determined by the water bottom depth determination means 16, it can be determined that the reflected wave of the ultrasonic wave TB is due to reflection from the detection target GF. Also, if the distance to the position where the reflected wave of the ultrasonic wave TB is reflected is equal to or greater than the depth of the water bottom SB determined by the water bottom depth determination means 16, it can be determined that the reflected wave of the ultrasonic wave TB is due to reflection from the water bottom SB.

[0073] Note that after the ultrasonic waves TB are reflected by the wave transmitting / receiving unit 50 from the bottom SB, all reflected waves of the ultrasonic waves TB received after the wave transmitting / receiving unit 50 are actually reflected from the bottom SB. However, the ultrasonic sonar device 1 treats the reflected waves as having been received from deeper positions (farther distances) as the time that has passed since the transmission of the ultrasonic waves TB. In other words, the reflected waves of the ultrasonic waves TB received after the wave transmitting / receiving unit 50 begins to receive the reflected waves of the ultrasonic waves TB from the bottom SB are considered to have been reflected from positions deeper than the depth of the bottom SB. Therefore, in the present invention, the horizontal detection result image 22 is generated assuming that there are reflected waves of the ultrasonic waves TB reflected from positions deeper than the bottom SB, but in reality, the reflected waves are reflected from the bottom SB.

[0074] Next, the electrical configuration of the ultrasonic sonar device 1 will be described with reference to Fig. 6. Fig. 6 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 and 11b, diodes 12a to 12g, receiving units 13a to 13g, a filter 14, storage means 15, water bottom depth determination means 16, detection result image generation means 17, and display control means 18.

[0075] Each of the transmitting units 11a, 11b, receiving units 13a to 13g, filter 14, bottom depth determination means 16, detection result image generation means 17, and display control means 18 may be configured as hardware, may be realized by software, or may be realized by a combination of hardware and software.

[0076] Although not shown, 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.

[0077] The parts of the transmitting units 11a and 11b, the receiving units 13a to 13g, the filter 14, the bottom depth determining means 16, the detection result image generating means 17, and the display control means 18 that are realized by software or by a combination of hardware and software are realized by the CPU executing a program. Also, the storage means 15 is constructed in RAM.

[0078] Based on instructions from the CPU, the transmission unit 11a generates one drive signal for transmitting ultrasound waves TB from the first transducers 52a to 52f. The output of the 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 signal is input to the first transducer 52a via the diode 12a, one signal is input to the first transducer 52b via the diode 12b, one signal is input to the first transducer 52c via the diode 12c, one signal is input to the first transducer 52d via the diode 12d, one signal is input to the first transducer 52e via the diode 12e, and one signal is input to the first transducer 52f via the diode 12f.

[0079] 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.

[0080] 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 time. Therefore, ultrasonic waves TB can be transmitted uniformly in predetermined directions (i.e., in the directions of the first central axes C1a-C1f) included in a predetermined range set in all directions with respect to the ship 71, making it possible to make detection sensitivity uniform in all predetermined directions.

[0081] Furthermore, since one transmission unit 11a is provided for the plurality of first oscillators 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 oscillators 52a to 52f.

[0082] Furthermore, since the diodes 12a-12f are provided between the transmitting unit 11a and each of the first oscillators 52a-52f and downstream of the branching points where the drive signal output from the transmitting unit 11a branches toward each of the first oscillators 52a-52f, it is possible to prevent the signals (voltages) output by each of the first oscillators 52a-52f upon receiving the reflected waves of the ultrasonic waves TB from flowing back to the transmitting unit 11a or from entering the signal lines of the other first oscillators 52a-52f via the branching points, causing interference. Therefore, even if one transmitting unit 11a is provided for multiple (six) first oscillators 52a-52f, it is possible to ensure the independence of the signals (voltages) output from each of the first oscillators 52a-52f.

[0083] The transmitting unit 11b generates a drive signal for transmitting ultrasonic waves TB from the second oscillator 53 based on instructions from the CPU. The output of the drive signal generated by the transmitting unit 11b is input to the second oscillator 53 via a diode 12g. The diode 12g is an element that passes the drive signal generated by the transmitting unit 11b and inputs it to the second oscillator 53, and also blocks a signal (voltage) generated by receiving a reflected wave at the second oscillator 53 from being transmitted to the transmitting unit 11b. This diode 12g makes it possible to prevent the signal (voltage) output by the second oscillator 53 by receiving a reflected wave of the ultrasonic waves TB from flowing back to the transmitting unit 11b.

[0084] 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 when performing horizontal detection as a sonar function, 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.

[0085] In this embodiment, separate transmission units 11a corresponding to the first transducers 52a to 52f and transmission unit 11b corresponding to the second transducer 53 are provided, but if the specifications of the ultrasonic sonar device 1 are such that transmission of ultrasonic waves TB from the second transducer 53 can always be performed at the same timing as the first transducers 52a to 52f, then only one transmission unit 11a may be provided for the first transducers 52a to 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 made even more compact and at a much lower cost.

[0086] The receiving units 13a to 13g are provided for each of the plurality (six) of first oscillators 52a to 52f and second oscillators 53. Each time a predetermined time has elapsed since the corresponding first oscillators 52a to 52f and second oscillators 53 transmitted ultrasonic waves TB, the receiving units 13a to 13g acquire signals (voltages) output in accordance with the intensities of the reflected waves of the ultrasonic waves TB received by the first oscillators 52a to 52f and second oscillators 53, and perform sampling to perform predetermined processing on the acquired signals.

[0087] That is, receiving unit 13a is connected to first oscillator 52a, and receives a signal (voltage) output by first oscillator 52a in accordance with the intensity of the reflected wave received, and performs predetermined processing on the signal. Further, receiving unit 13b is connected to first oscillator 52b, receiving unit 13c is connected to first oscillator 52c, receiving unit 13d is connected to first oscillator 52d, receiving unit 13e is connected to first oscillator 52e, receiving unit 13f is connected to first oscillator 52f, and receiving unit 13g is connected to second oscillator 53. Each of receiving units 13b to 13g also receives a signal (voltage) output by first oscillator 52b to 52f or second oscillator 53 in accordance with the intensity of the reflected wave received, and performs predetermined processing on the signal.

[0088] Each of the receiving units 13a to 13g has an amplifier circuit and an analog-to-digital converter circuit. Each of the receiving units 13a to 13g samples a signal (voltage) output from the corresponding first oscillator 52a to 52f or second oscillator 53 every time a predetermined time has elapsed after an ultrasonic wave TB is transmitted from the corresponding first oscillator 52a to 52f or second oscillator 53. Specifically, each of the receiving units 13a to 13g performs predetermined processing every time a predetermined time has elapsed by amplifying the signal (voltage) taken in from the corresponding first oscillator 52a to 52f or second oscillator 53 using an amplifier circuit, and then converts the amplified signal into a digital signal (digital value) with a predetermined number of bits (7 bits in this embodiment) using an analog-to-digital converter circuit (AD converter circuit).

[0089] Then, the receiving unit 13a outputs a digital signal obtained by an AD conversion circuit as a reception signal received by the first oscillator 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 oscillator 52b, the receiving unit 13c outputs a digital signal obtained by the first oscillator 52c, the receiving unit 13d outputs a digital signal obtained by the first oscillator 52d, the receiving unit 13e outputs a digital signal obtained by the first oscillator 52e, the receiving unit 13f outputs a digital signal obtained by the first oscillator 52f, and the receiving unit 13g outputs a digital signal obtained by the second oscillator 53 to the filter 14.

[0090] As described above, one transmitting unit 11a is provided for multiple (six) first transducers 52a-52f to reduce costs and size, while 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 signals (voltages) output from each of the first transducers 52a-52f. On the other hand, because 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.

[0091] 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 oscillators 52a to 52f and second oscillator 53. These original reception signals are reception signals before filtering by the filter 14, which will be described next.

[0092] The filter 14 performs predetermined filtering on the received signals (original received signals) output from the receiving units 13a to 13g to the first oscillators 52a to 52f and the second oscillator 53. The predetermined filtering includes spatial filtering and may also include temporal filtering.

[0093] As for spatial filtering, filtering is performed in the azimuth direction and the distance direction on the original received signals of the first transducers 52a to 52f that receive the reflected waves of the ultrasonic waves TB for each predetermined direction, for the purpose of reducing noise and / or improving resolution, etc. The spatial filtering also includes filtering in the distance direction on the original received signals of the second transducer 53 that receive the reflected waves of the ultrasonic waves TB from the vertical direction directly below the ship 71.

[0094] Here, the azimuth direction is the direction in which the first central axes C1a to C1f of the first transducers 52a to 52f, i.e., the respective acoustic radiation directions, are aligned, in other words, the circumferential direction centered on the ship 71. Furthermore, the distance direction is the direction in which ultrasonic waves TB are transmitted from 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, i.e., the respective acoustic radiation directions themselves.

[0095] When performing horizontal detection using the sonar function, the ultrasonic sonar device 1 performs detection using a small number of transducers, the first transducers 52a to 52f (six in this embodiment), resulting in a significant decrease in azimuth resolution. Therefore, in horizontal detection, the filter 14 may set a virtual direction at a position midway between adjacent first central axes C1a to C1f of the first transducers 52a to 52f, which are predetermined directions in which ultrasonic waves TB are transmitted and received, and generate virtual reception signals from the reception signals of the first transducers 52a to 52f, assuming that ultrasonic waves TB are virtually transmitted and received in that virtual direction.

[0096] By generating virtual reception signals in virtual directions, the number of directions in which ultrasonic waves TB are transmitted and received can be doubled (12 directions in this embodiment) as the number of actual first transducers 52, including the virtual directions, thereby improving the azimuth resolution.

[0097] On the other hand, temporal filtering refers to filtering a received signal indicating the intensity of a reflected wave reflected from a certain distance (or depth) in a certain direction, together with at least one received signal received earlier in time and / or at least one received signal received later in time from the same direction and the same distance (or depth). This temporal filtering allows the horizontal detection result image 22, which will be described later and is displayed on the display device 21, to change smoothly over time, allowing the user to view the horizontal detection result image 22 without feeling any discomfort.

[0098] The filter 14 performs a predetermined filter process on the original reception signals of each of the first oscillators 52a to 52f and the second oscillator 53, and then stores the values ​​obtained by the filter process as the reception signals of each of the first oscillators 52a to 52f and the second oscillator 53, and also stores the virtual reception signals in the storage means 15 when generating virtual reception signals for virtual directions. The reception units 13a to 13g and the filter 14 correspond to the reception signal generating means of the present invention.

[0099] The storage means 15 stores the filtered reception signals of the first oscillators 52a to 52f and the second oscillator 53, generated by the filter 14, for each of the first oscillators 52a to 52f and the second oscillator 53 (i.e., for each of the directions of the first central axes C1a to C1f and the second central axis C2), in the reception signal array 15a. When virtual reception signals are generated for virtual directions, the virtual reception signals are also stored in the reception signal array 15a for each virtual direction.

[0100] Here, the details of the received signal array 15a will be described with reference to Fig. 7. Fig. 7 is a diagram schematically showing the contents of the received signal array 15a. Fig. 7 shows the received signal array 15a in the case where the filter 14 generates virtual received signals in virtual directions.

[0101] The received signal array 15a is a two-dimensional array with indexes of information θ corresponding to the direction in which the reflected wave of the ultrasonic wave TB that is the basis of the received signal was received, including the above-mentioned virtual directions (i.e., the direction of each of the first central axes C1a to C1f, the first virtual direction to the sixth virtual direction set at a position midway between the adjacent first central axes C1a to C1f, and the direction of the second central axis C2; hereinafter referred to as "direction θ"), and information R corresponding to the distance from the wave transmitting / receiving unit 50 to the position where the reflected wave of the ultrasonic wave that is the basis of the received signal was generated (hereinafter referred to as "distance R"). In other words, the received signal array 15a stores the intensity (level) of the reflected wave reflected from each position specified by polar coordinates consisting of the direction θ and the distance R as the level of the received signal.

[0102] The direction θ is assigned numbers "1" to "12" clockwise from the front of the ship 71 when viewed vertically from above the ship 71 for each of the first center axes C1a to C1f, which are directions for receiving reflected waves of ultrasonic waves TB set in the azimuth direction, and for each of the first virtual direction to sixth virtual direction set at a position midway between adjacent first center axes C1a to C1f.

[0103] That is, in the direction θ, "1" indicates the direction of the first central axis C1b. "2" in the direction θ indicates a first virtual direction (referred to as "virtual 1" in FIG. 7) set at a position midway between the first central axis C1b and the first central axis C1a. "3" in the direction θ indicates the direction of the first central axis C1a. "4" in the direction θ indicates a second virtual direction set at a position midway between the first central axis C1a and the first central axis C1f. "5" in the direction θ indicates the direction of the first central axis C1f. "6" in the direction θ indicates a third virtual direction set at a position midway between the first central axis C1f and the first central axis C1e.

[0104] In the direction θ, "7" indicates the direction of the first central axis C1e. "8" in the direction θ indicates a fourth virtual direction set at a position midway between the first central axis C1e and the first central axis C1d. "9" in the direction θ indicates the direction of the first central axis C1d. "10" in the direction θ indicates a fifth virtual direction set at a position midway between the first central axis C1d and the first central axis C1c. "11" in the direction θ indicates the direction of the first central axis C1c. "12" in the direction θ indicates a sixth virtual direction (referred to as "virtual 6" in Figure 7) set at a position midway between the first central axis C1c and the first central axis C1b.

[0105] Furthermore, the direction θ is assigned the number "13" with respect to the second central axis C2, which is the vertical direction. That is, in the direction θ, "13" indicates the direction of the second central axis C2.

[0106] When a virtual reception signal in a virtual direction is not generated by the filter 14, the direction θ may be assigned, for example, as follows: the direction of the first center axis C1b is "1," the direction of the first center axis C1a is "2," the direction of the first center axis C1f is "3," the direction of the first center axis C1e is "4," the direction of the first center axis C1d is "5," and the direction of the first center axis C1c is "6." In this case, the direction θ may be assigned as "7" for the second center axis C2, which is the vertical direction.

[0107] On the other hand, the numbers "1" to "200" are assigned to the distance R. Then, in the first transducers 52a to 52f or the second transducer 53 corresponding to each direction θ, sampling is performed by the corresponding receiving units 13a to 13g at predetermined time intervals after the ultrasonic wave TB is transmitted, and a received signal is output. Then, the numbers "1" to "200" are assigned to the output received signals one by one in ascending order. As is known, there is a proportional relationship between the time elapsed since the ultrasonic wave TB was transmitted and the distance to the position where the ultrasonic wave TB is reflected. Therefore, the distance R assigned in this manner can indicate the distance from the wave transmitting and receiving unit 50 to the position where the ultrasonic wave TB is reflected.

[0108] The memory means 15 stores the level RSLn (n=θ+13(R-1)) of the received signal of the reflected wave reflected from the position specified by the direction θ and the distance R in the element specified by the direction θ and the distance R of the received signal array 15a.

[0109] For example, after the first transducer 52b, which transmits and receives ultrasonic waves TB in the direction of the first center axis C1b, transmits the ultrasonic waves TB, the level RSL1 of the received signal after filtering by the filter 14 that is sampled for the first transducer 52b is stored in an element of the received signal array 15a indicated by an index of "1" for the direction θ and "1" for the distance R.

[0110] Furthermore, the level RSL15 of the received signal virtually generated by the filter 14 as the second sampled signal in the first virtual direction based on the received signal in the direction of the first center axis C1b and the received signal in the direction of the first center axis C1a is stored in the element of the received signal array 15a indicated by the index of "2" for the direction θ and the index of "2" for the distance R.

[0111] Furthermore, after the second transducer 53, which transmits and receives ultrasonic waves TB in the direction of the second central axis C2 (vertical direction), transmits the ultrasonic waves TB, the level RSL2600 of the received signal sampled 200th time for the second transducer 53 is stored in the element of the received signal array 15a indicated by the index of "13" for the direction θ and "200" for the distance R.

[0112] Returning to Figure 6, the explanation will be continued. The water bottom depth determination means 16 determines the depth of the water bottom SB located directly (vertically) below the vessel 71. The depth of the water bottom SB is determined by utilizing the fact that when the transducer receives a reflected wave of ultrasonic waves TB from the water bottom SB, the level of the signal (voltage) output from the transducer is much higher and the rising slope is also steeper than when a reflected wave of ultrasonic waves TB is received from another object. That is, when the level indicated by the received signal is equal to or greater than a predetermined level threshold and / or the amount of change in the level indicated by the received signal is equal to or greater than a predetermined change amount threshold, the water bottom depth determination means 16 determines that the received signal is due to reception of a reflected wave from the water bottom SB, and identifies the depth identified by the time at which this determination was made as the vertical depth directly below the vessel 71.

[0113] The water bottom depth determination means 16 is based on the intensity of the reflected waves of the ultrasonic waves TB transmitted and received by the second transducer 53, which are stored in the received signal array 15a. As described above, the second transducer 53 has its second central axis C2 positioned in the vertical direction directly below the vessel 71, so that the depth of the water bottom SB in the vertical direction directly below the vessel 71 can be determined with high accuracy.

[0114] However, because the directional characteristics of each of the first transducers 52a to 52f include the vertical direction directly below the ship 71, the signals (voltages) output from the first transducers 52a to 52f also include reflected waves of ultrasonic waves TB from the water bottom SB in the vertical direction directly below the ship 71. Therefore, although the accuracy is lower than when the second transducer 53 is used, the water bottom depth determination means 16 may determine the depth of the water bottom SB in the vertical direction directly below the ship 71 using the received signals output from the first transducers 52a to 52f stored in the received signal array 15a.

[0115] The depth of the water bottom SB determined by the water bottom depth determining means 16 is used when the detection result image generating means 17 generates a horizontal detection result image 22 shown in FIG.

[0116] The detection result image generating means 17 generates a detection result image to be displayed on the display device 21 based on the first center axes C1a to C1f generated by the receiving units 13a to 13g and the filter 14, and the received signals for each of the first to sixth virtual directions, i.e., the received signal array 15a stored in the storage means 15. When the ultrasonic sonar device 1 performs horizontal detection as a sonar function, the detection result image generating means 17 generates at least a horizontal detection result image 22 shown in FIG.

[0117] The detection result image generating means 17 manages and identifies each pixel of the horizontal detection result image 22 in a Cartesian coordinate system consisting of an X coordinate and a Y coordinate. The detection result image generating means 17 has a conversion table in which Cartesian coordinates (X, Y) indicating each pixel of the horizontal detection result image 22 are associated with coordinates (R, θ) in a polar coordinate system consisting of a direction θ and a distance R, which are indexes of the received signal array 15a corresponding to the coordinates (X, Y). The direction θ associated in the conversion table is 1≦θ<13. Here, a direction indicated by 12≦θ<13 means a direction included between the direction θ indicated by "12" (the sixth virtual direction) and the direction θ indicated by "1" (the direction of the first center axis C1b). In other words, this conversion table associates only the azimuth direction θ.

[0118] The detection result image generating means 17 uses a conversion table to identify, for each pixel of the horizontal detection result image 22, the coordinates (R, θ) in the polar coordinate system corresponding to the coordinates (X, Y) of that pixel. Then, for each pixel, the detection result image generating means 17 identifies the level of the received signal at the position of the coordinates (R, θ) identified for that pixel from the received signal array 15a stored in the storage means 15, and sets the identified received signal level as the intensity of the reflected wave from the underwater position corresponding to that pixel. In this way, the detection result image generating means 17 can identify, for each pixel of the horizontal detection result image 22, which shows the underwater detection result projected onto a plane parallel to the horizontal plane, the intensity of the reflected wave from the underwater position corresponding to that pixel, from the level of the received signal in the azimuth direction stored in the received signal array 15a.

[0119] Here, the direction θ and distance R, which are coordinates in the polar coordinate system corresponding to the coordinates (X, Y), are not necessarily natural numbers used as indices in the received signal array 15a, but are often expressed as decimals. In this case, the received signal level at the coordinate (R, θ) is determined by calculating a weighted average of the received signal levels of four elements of the received signal array 15a that are close to the coordinate (R, θ) expressed as a decimal. The weighted average is calculated so that the received signal level of the element of the received signal array 15a that is closest to the coordinate (R, θ) is largely reflected.

[0120] For example, the level of the received signal at the position of coordinates (R, θ) = (49.8, 2.3) is calculated by taking a weighted average of the received signal levels of the elements of the received signal array 15a indicated by the respective indexes (R, θ) = (49, 2), (49, 3), (50, 2), and (50, 3).

[0121] The level of the received signal at the position of coordinates (R, θ) = (19.2, 12.7) is calculated by taking a weighted average of the levels of the received signals of the elements of received signal array 15a indicated by the respective indexes (R, θ) = (19, 12), (19, 1), (20, 12), and (20, 1). The index "1" is used for direction θ because the direction next to the direction indicated by "12" where θ is "1" is clockwise.

[0122] The detection result image generating means 17 identifies, for each pixel, the intensity of the reflected wave from the underwater position corresponding to that pixel, and assigns a color according to the intensity of the reflected wave to generate a horizontal detection result image 22. The detection result image generating means 17 has a first palette 17a and a second palette 17b that define the colors to be assigned to the intensity of the reflected wave.

[0123] The first palette 17a is a palette that is applied to waves reflected from positions shallower than the depth of the water bottom SB. The second palette 17b is a palette that is applied to waves reflected from positions deeper than the depth of the water bottom SB, and is defined in colors different from those defined in the first palette 17a. The first palette 17a and the second palette 17b are stored in a flash memory or ROM (not shown) that constitutes the control device 10.

[0124] When the ultrasonic sonar device 1 according to this embodiment generates a horizontal detection result image 22 in the detection result image generation means 17, it first assigns colors to all pixels, i.e., the intensities of reflected waves from all positions within a predetermined range, using the first palette 17a. Then, for pixels in the horizontal detection result image 22 that have had colors assigned using the first palette 17a, the detection result image generation means 17 reassigns colors using the second palette 17b for pixels that correspond to positions deeper than the depth of the water bottom SB determined by the water bottom depth determination means 16, in accordance with the intensity of reflected waves from the underwater positions corresponding to those pixels, and overwrites the image with the reassigned colors.

[0125] As a result, in the ultrasonic sonar device 1, in the horizontal detection result image 22, at least the color defined in the first palette 17a is assigned to the response 22a of the detection target GF, and the color defined in the second palette 17b is assigned to the response 22b of the water bottom SB. As described above, the colors defined in the first palette 17a and the colors defined in the second palette 17b are different. Therefore, in the horizontal detection result image 22, the color assigned to the response 22a of the detection target GF and the color assigned to the response 22b of the water bottom SB can be clearly different. Therefore, the user can easily distinguish the detection target GF and / or the water bottom SB from the horizontal detection result image 22.

[0126] FIG. 8 is a schematic diagram showing an example of the first palette 17a and the second palette 17b. In the example shown in FIG. 8, the first palette 17a and the second palette 17b are stored in a memory area with consecutive addresses. In FIG. 8, the relative address ("Address" in FIG. 8) within the memory area where the first palette 17a and the second palette 17b are stored is represented by 8 bits (0 to 255), with the first palette 17a being defined as a relative address with the most significant bit (MSB) set to "0" (relative address 0 to 127), and the second palette 17b being defined as a relative address with the most significant bit (MSB) set to "1" (relative address 128 to 255). In other words, the most significant bit of the relative address functions as an identification bit for identifying the first palette 17a and the second palette 17b.

[0127] In both the first palette 17a and the second palette 17b, the lowest 7 bits of the relative address correspond to the intensity of the reflected wave. The colors assigned to each relative address, i.e., the intensity of the reflected wave, are specified by RGBA, i.e., the intensities of the colors "red," "green," and "blue," and "transparency." As described above, the colors specified in the first palette 17a and the colors specified in the second palette 17b are specified so that they are different from each other.

[0128] In this embodiment, the intensity of the reflected wave is represented by 7 bits. When the detection result image generating means 17 specifies the color of each pixel using the first palette 17a, it specifies the color to be assigned to the intensity of the reflected wave from the relative address represented by adding "0" to the most significant bit of the intensity (7 bits) of the reflected wave from the underwater position corresponding to the pixel specified by the above method. When the detection result image generating means 17 specifies the color of each pixel using the second palette 17b, it specifies the color to be assigned to the intensity of the reflected wave from the relative address represented by adding "1" to the most significant bit of the intensity (7 bits) of the reflected wave from the underwater position corresponding to the pixel specified by the above method. This makes it easy to switch between the first palette 17a and the second palette 17b, which are used to assign colors to the intensity of the reflected wave, simply by switching the most significant bit of the relative address between "0" and "1."

[0129] Alternatively, the second palette 17b may be defined at a relative address where the most significant bit (MSB) is "0" (relative address 0 to 127), and the first palette 17a may be defined at a relative address where the most significant bit (MSB) is "1" (relative address 128 to 255). In this case, when the detection result image generating means 17 specifies the color of each pixel using the first palette 17a, it specifies the color to be assigned to the intensity of the reflected wave from the relative address represented by adding "1" to the most significant bit of the intensity (7 bits) of the reflected wave from the underwater position corresponding to the pixel specified by the above method. When the detection result image generating means 17 specifies the color of each pixel using the second palette 17b, it specifies the color to be assigned to the intensity of the reflected wave from the relative address represented by adding "0" to the most significant bit of the intensity (7 bits) of the reflected wave from the underwater position corresponding to the pixel specified by the above method.

[0130] In addition, in the example shown in FIG. 8, the first palette 17a and the second palette 17b are stored in memory areas with consecutive addresses, but the first palette 17a and the second palette 17b may also be stored in separate memory areas.

[0131] In addition, in this embodiment, the case where the intensity of the reflected wave is expressed by 7 bits has been described. However, if the intensity of the reflected wave is expressed by M bits, the first palette 17a and the second palette 17b have relative addresses excluding the most significant bit (identification bit) from 0 to (2 M A color may be assigned to the intensity of each reflected wave so that the intensity of all reflected waves can be expressed in detail using colors.

[0132] On the other hand, when the intensity of the reflected wave is expressed by M bits, the first palette 17a and the second palette 17b have relative addresses excluding the most significant bit (identification bit) from 0 to (2 N Colors may be assigned to the intensity of the reflected wave so that M>N (M-1) (where M>N). In this case, the most significant N bits of the intensity of the reflected wave expressed by M bits correspond to the relative addresses of the first palette 17a and the second palette 17b excluding the most significant bit (identification bit). This reduces the number of colors assigned to the intensity of the reflected wave, but also reduces the storage capacity required for the first palette 17a and the second palette 17b.

[0133] In the example of FIG. 8, the color assigned to the intensity of the reflected wave is defined by the intensities of the colors "red," "green," and "blue" and "transparency." However, any known method for defining the colors may be used. For example, the colors may be defined using RGB, i.e., by the intensities of the colors "red," "green," and "blue" only, without defining "transparency." The colors may also be defined using CMYK, i.e., the intensities of cyan, magenta, yellow, and black, or YCbCr, i.e., by luminance Y and two color differences Cb and Cr. The colors may also be defined using HSL, i.e., hue H, saturation S, and luminance L, or HSV, i.e., hue H, saturation S, and lightness V.

[0134] The detection result image generating means 17 may also be provided with a plurality of first palettes 17a, and the user may be able to select one of the plurality of first palettes 17a to be assigned in accordance with the intensity of the reflected wave from the detection target GF by operating the operation button 31. The detection result image generating means 17 may also be provided with a plurality of second palettes 17b, and the user may be able to select one of the plurality of second palettes 17b to be assigned in accordance with the intensity of the reflected wave from the water bottom SB by operating the operation button 31. This allows the user to display the response 22a of the detection target GF and the response 22b of the water bottom SB in the horizontal detection result image 22 in the color of their choice.

[0135] Alternatively, multiple combinations of first palette 17a and second palette 17b may be provided, and the user may operate operation button 31 to select one of the combinations. For example, combinations of first palette 17a and second palette 17b with different brightnesses, combinations of first palette 17a and second palette 17b with different saturations, combinations of first palette 17a and second palette 17b with different transparencies (transparencies), and combinations of first palette 17a and second palette 17b with different hues may be provided, and the user may be able to select the manner in which the color assigned according to the intensity of the reflected wave from the detection target GF and the color assigned according to the intensity of the reflected wave from the water bottom SB differ from each other by brightness, saturation, transparency (transparency), hue, etc. This allows the user to select the manner in which the color assigned according to the intensity of the reflected wave from the detection target GF and the color assigned according to the intensity of the reflected wave from the water bottom SB differ according to their preferences.

[0136] The application range of the first palette 17a and the second palette 17b may be switched based on the setting made by the user operating the operation button 31. That is, when the user operates the operation button 31, the application range may be changed so that the first palette 17a is applied to reflected waves from positions deeper than the depth of the water bottom SB, and the second palette 17b is applied to reflected waves from positions shallower than the depth of the water bottom SB. Then, when the user operates the operation button 31 again, the application range may be returned so that the first palette 17a is applied to reflected waves from positions shallower than the depth of the water bottom SB, and the second palette 17b is applied to reflected waves from positions deeper than the depth of the water bottom SB. This allows the user to select which color is brighter, more saturated, or less transparent (transparent) between the color assigned according to the intensity of the reflected wave from the detection target GF and the color assigned according to the intensity of the reflected wave from the water bottom SB. Therefore, the user can display the response 22a of the detection target GF and the response 22b of the water bottom SB on the horizontal detection result image 22 in different colors as desired.

[0137] The display control means 18 performs control to display the horizontal detection result image 22 generated by the detection result image generation means 17 and other images on the display device 21. For example, the display control means 18 adjusts the size and display position of the horizontal detection result image 22 and other detection result images, and also combines characters, symbols, figures, etc. with the horizontal detection result image 22, etc., to display one image on the display device 21.

[0138] Next, a method for performing horizontal detection using the sonar function with the ultrasonic sonar device 1 of this embodiment configured as described above will be described with reference mainly to FIGS.

[0139] When the user turns on the power to the ultrasonic sonar device 1 via the operation button 31, or when an instruction is given to start performing horizontal detection using the sonar function while the power is on, the ultrasonic sonar device 1 first drives the lifting device 41 to make the wave transmitting and receiving unit 50 appear in the water from the bottom of the ship 71. Note that in an ultrasonic sonar device 1 that does not have the lifting device 41 and in which the wave transmitting and receiving unit 50 is fixed to the ship 71 in a position where it can transmit and receive ultrasonic waves TB into the water, the driving operation of the lifting device 41 is omitted.

[0140] Next, the ultrasonic sonar device 1 outputs drive signals from the transmitting units 11a and 11b, and transmits ultrasonic waves TB in the directions of the first center axes C1a to C1f and the second center axis C2, respectively, from the first transducers 52a to 52f and the second transducer 53 of the wave transmitting and receiving unit 50. Due to the directional characteristics of the ultrasonic waves TB transmitted from each of the first center axes C1a to C1f, the ultrasonic waves TB are transmitted in all directions to the ship 71.

[0141] The ultrasonic waves TB transmitted from the first oscillators 52a to 52f and the second oscillator 53 are reflected from the detection target GF and the water bottom SB that are present within a predetermined range from which the ultrasonic waves TB are transmitted. The reflected waves are received by the first oscillators 52a to 52f and the second oscillator 53, and signals (voltages) are output from the first oscillators 52a to 52f and the second oscillator 53 as the intensities of the reflected waves received in the directions of the first central axes C1a to C1f and the second central axis C2, respectively.

[0142] The signals (voltages) output from the first transducers 52a to 52f and the second transducer 53 are amplified by the corresponding receiving units 13a to 13g at predetermined intervals after the transmission of the ultrasonic wave TB, and then sampled by being converted into 7-bit 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.

[0143] These original reception signals are subjected to spatial (and temporal) filtering by the filter 14. Furthermore, the filter 14 may set first to sixth virtual directions at intermediate positions between adjacent first center axes C1a to C1f, respectively, and may generate reception signals from the reception signals of the first transducers 52a to 52f, assuming that ultrasonic waves TB are virtually transmitted and received in the first to sixth virtual directions, respectively.

[0144] The levels of 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 are stored in each element of the received signal array 15a by the storage means 15. When the levels of the virtual received signals in the first to sixth virtual directions that are virtually set are also output, the levels of the virtual received signals are also stored in each element of the received signal array 15a as shown in FIG.

[0145] Next, the level of the received signal in the direction of the second center axis C2 (vertical direction) stored in the received signal array 15a is referenced by the water bottom depth determination means 16, and the depth of the water bottom SB in the vertical direction directly below the ship 71 is determined. Furthermore, based on the level of the received signal in the direction of the first center axes C1a to C1f (directions set as azimuth directions) stored in the received signal array 15a, the detection result image generation means 17 generates one or more detection result images to be displayed on the display device 21, including a horizontal detection result image 22. The detection result images, including the horizontal detection result image 22, generated by the detection result image generation means 17 are formed into a single image by the display control means 18 and displayed on the display device 21.

[0146] The ultrasonic sonar device 1 can show the latest detection results to the user by repeatedly transmitting ultrasonic waves TB and receiving reflected waves of the ultrasonic waves TB, and then generating and displaying a detection result image based on the received signal.

[0147] Here, the horizontal detection result image generation process executed by the detection result image generation means 17 will be described with reference to Fig. 9. Fig. 9 is a flowchart showing the horizontal detection result image generation process. The horizontal detection result image generation process is a process for generating the horizontal detection result image 22 shown in Fig. 5.

[0148] When the detection result image generating means 17 starts executing the horizontal detection result image generating process, it first identifies (S1) for each pixel of the horizontal detection result image 22 the intensity of the reflected wave from the underwater position corresponding to that pixel. Specifically, as described above, the detection result image generating means 17 identifies for each pixel from the conversion table the polar coordinates (R, θ) corresponding to the Cartesian coordinates (X, Y) of that pixel, identifies the level of the received signal at the position of the polar coordinates (R, θ) from the received signal array 15a stored in the storage means 15, and sets the identified level of the received signal as the intensity of the reflected wave from the underwater position corresponding to that pixel.

[0149] Next, the detection result image generating means 17 sets the first palette 17a as a palette that defines the colors to be assigned to the intensity of the reflected wave identified for each pixel (S2). For example, when using the palette shown in Fig. 8, the first palette 17a is set by setting the most significant bit (MSB) of the relative address to "0".

[0150] Then, the detection result image generating means 17 generates a temporary horizontal detection result image 22 by assigning a color to all pixels across the entire set detection range (predetermined range) using the first palette 17a according to the intensity of the reflected wave from the underwater position corresponding to that pixel (S3).

[0151] Next, the detection result image generating means 17 sets the second palette 17b as a palette that defines the colors to be assigned to the intensity of the reflected wave (S4). For example, when using the palette shown in Fig. 8, the second palette 17b is set by setting the most significant bit (MSB) of the relative address to "1".

[0152] The detection result image generating means 17 also acquires information on the depth of the water bottom SB in the vertical direction directly below the ship 71 from the water bottom depth determining means 16 (S5). The detection result image generating means 17 identifies the coordinates of an area in the horizontal detection result image 22 that is deeper than the depth of the water bottom SB from the information on the depth of the water bottom SB acquired in the processing of S5 (S6).

[0153] Then, for pixels at coordinates in an area deeper than the depth of the water bottom SB in the horizontal detection result image 22 identified in the process of S6, the detection result image generation means 17 reallocates a color in the second palette 17b according to the intensity of the reflected wave from the underwater position corresponding to that pixel, and fills (overwrites) the pixel with the reallocated color (S7).The detection result image generation means 17 then ends the horizontal detection result image generation process.

[0154] As a result, the detection result image generating means 17 generates the horizontal detection result image 22 shown in FIG. 8 . This horizontal detection result image 22 is displayed on the display device 21 by the display control means 18. Therefore, in the horizontal detection result image 22, the ultrasonic sonar device 1 assigns a color defined in the first palette 17a to at least the response 22a of the detection target GF, and a color defined in the second palette 17b to the response 22b of the water bottom SB. As described above, the colors defined in the first palette 17a and the second palette 17b are different. Therefore, in the horizontal detection result image 22, the color assigned to the response 22a of the detection target GF and the color assigned to the response 22b of the water bottom SB can be clearly different. Therefore, the user can easily distinguish the detection target GF and / or the water bottom SB from the horizontal detection result image 22.

[0155] As described above, the ultrasonic sonar device 1 according to the first embodiment has the following advantages.

[0156] (1) The wave transmitting / receiving unit 50 transmits ultrasonic waves TB into water over a predetermined range, and receives reflected waves of the ultrasonic waves TB reflected from various positions underwater in each of predetermined directions (the directions of the first central axes C1a-C1f and the second central axis C2) set in the azimuth direction. Based on the reflected waves received by the wave transmitting / receiving unit 50, the receiving units 13a-13g and the filter 14 generate received signals for each of the directions of the first central axes C1a-C1f and the second central axis C2. Based on the received signals for each of the directions of the first central axes C1a-C1f and the second central axis C2 generated by the receiving units 13a-13g and the filter 14, the detection result image generating means 17 generates a horizontal detection result image 22 showing the latest detection result in a color corresponding to the intensity of the reflected waves reflected from various positions over the predetermined range. From this horizontal detection result image 22, the user can determine whether a detection target GF is present, as well as the direction and horizontal distance of the detection target GF.

[0157] (2) The depth of the water bottom SB is determined by the water bottom depth determination means 16 based on the intensity of the reflected waves received by the wave transmitting / receiving unit 50. Then, the detection result image generation means 17 generates a horizontal detection result image 22 by assigning different colors to positions within a predetermined range that are shallower than the depth of the water bottom SB and to positions within a predetermined range that are deeper than the depth of the water bottom SB. This allows the user to easily determine from the color displayed in the horizontal detection result image 22 whether the reaction displayed in the horizontal detection result image 22 is the reaction 22a of the detection target GF or the reaction 22b of the water bottom SB. Therefore, the user can easily distinguish between the detection target GF and / or the water bottom SB.

[0158] (3) The detection result image generating means 17 first generates a provisional horizontal detection result image 22 covering the entire detection range, which is a predetermined range, in a color (first palette 17a) assigned to positions shallower than the depth of the water bottom SB (S3 in FIG. 9). Then, the detection result image generating means 17 overwrites pixels at positions deeper than the water bottom SB in the generated provisional horizontal detection result image 22 with a color assigned to areas deeper than the water bottom SB (S7 in FIG. 9). The overwritten horizontal detection result image 22 is displayed on the display device 21. This allows the generation process of the horizontal detection result image 22 to be executed with a simple program structure, making it possible to generate a horizontal detection result image 22 that allows the user to easily distinguish the detection target GF and / or the water bottom SB while keeping the memory capacity required for the program small.

[0159] (4) The first transducers 52a-52f are fixed to the transducer unit 50 so that their first central axes C1a-C1f are oriented in a predetermined direction and are positioned at a predetermined angle ω with respect to the vertical direction (the direction of the second central axis C2) when the transducer unit 50 is attached to the vessel 71 (see FIGS. 3 and 4). Each of the first transducers 52a-52f has a predetermined directional characteristic that includes at least the central axis C1 of the adjacent first transducer 52 and the vertical direction (see FIGS. 4(c) and 4(d)). 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. This allows an ultrasonic sonar device 1 capable of high-speed detection to be constructed at low cost.

[0160] Here, because the first transducers 52a-52f have directional characteristics in the vertical direction, they receive reflected waves from the water bottom SB in the vertical direction before receiving reflected waves from the water bottom SB in the direction of their first central axes C1a-C1f. However, because the horizontal detection result image 22 is a projection of the detection result onto a plane parallel to the horizontal plane, if the same color is assigned to the response 22a of the detection target GF and the response 22b of the water bottom SB, it is difficult to distinguish and understand the response 22b of the water bottom SB in the vertical direction. In contrast, the detection result image generating means 17 generates the horizontal detection result image 22 by assigning different colors to positions within the predetermined range that are shallower than the water bottom SB and positions within the predetermined range that are deeper than the water bottom SB. This allows the user to easily distinguish the response 22b of the water bottom SB in the vertical direction in the horizontal detection result image 22.

[0161] (5) In addition to the first transducers 52a to 52f, the second transducer 53 is provided in the wave transmitting and receiving unit 50, and is fixed so that the second center axis C2 is positioned in the vertical direction when the wave transmitting and receiving unit 50 is attached to the ship 71. This makes it possible to detect the detection target GF in the vertical direction and / or measure the depth in the vertical direction with high accuracy.

[0162] (6) Ultrasonic waves TB are transmitted from the second transducer 53, whose second center axis C2 is positioned in the vertical direction, and the depth of the water bottom SB in the vertical direction of the ship 71 is determined by the water bottom depth determination means 16 based on the intensity of the reflected waves received by the second transducer 53. This allows the depth of the water bottom SB in the vertical direction of the ship 71 to be determined with higher accuracy than when the first transducers 52a to 52f, whose first center axes C1a to C1f are positioned at a predetermined angle ω with respect to the vertical direction, are used to determine the depth of the water bottom SB in the vertical direction of the ship 71. Therefore, in the horizontal detection result image 22, the response 22b from the depth of the water bottom SB in the vertical direction can be clearly displayed to the user with high accuracy.

[0163] (Second embodiment) Next, an ultrasonic sonar device 1 according to a second embodiment of the present invention will be described with reference to Figs. 10 to 12. Fig. 10 is a block diagram showing the electrical configuration of the ultrasonic sonar device 1 according to the second embodiment. Fig. 11 is a schematic diagram showing a conversion table 17c held by the detection result image generating means 17 of the ultrasonic sonar device 1 according to the second embodiment. Fig. 12 is a flowchart showing horizontal detection result image generation processing executed by the detection result image generating means 17 of the ultrasonic sonar device 1 according to the second embodiment.

[0164] Here, in the ultrasonic sonar device 1 according to the first embodiment, the detection result image generating means 17 first generates a provisional horizontal detection result image 22 covering the entire detection range, which is a predetermined range, using a color (first palette 17a) assigned to positions shallower than the depth of the water bottom SB, and then overwrites pixels at positions deeper than the water bottom SB in the generated provisional horizontal detection result image 22 with a color assigned to areas deeper than the water bottom SB, thereby generating the horizontal detection result image 22 shown in Fig. 5. In contrast, the ultrasonic sonar device 1 according to the second embodiment generates the horizontal detection result image 22 shown in Fig. 5 through a single coordinate conversion process using the conversion table 17c provided in the detection result image generating means 17.

[0165] The ultrasonic sonar device 1 according to the second embodiment will be described below, focusing on the differences from the ultrasonic sonar device 1 according to the first embodiment. The same components as those in the ultrasonic sonar device 1 according to the first embodiment will be assigned the same reference numerals, and their description will be omitted or simplified.

[0166] The ultrasonic sonar device 1 according to the second embodiment differs from the ultrasonic sonar device 1 according to the first embodiment in that, as shown in Figures 10 and 11, the detection result image generating means 17 has a conversion table 17c of a format different from that of the first embodiment, and as shown in Figure 12, the detection result image generating means 17 executes horizontal detection result image generation processing using that conversion table 17c.

[0167] 11, the conversion table 17c, like the first embodiment, associates the Cartesian coordinates (X, Y) representing each pixel of the horizontal detection result image 22 with coordinates (R, θ) in a polar coordinate system consisting of information θ (direction θ) corresponding to the direction and information R (distance R) corresponding to the distance, which are indices in the received signal array 15a corresponding to the coordinates (X, Y). However, the conversion table 17c also associates, with the Cartesian coordinates (X, Y) representing each pixel, a distance R' representing the distance from the wave transmitting / receiving unit 50 to the underwater position corresponding to the pixel at the coordinates (X, Y), in units of one length, with the depth D of the water bottom SB output by the water bottom depth determination means 16. Here, the difference is that the distance R corresponds to an index in the received signal array 15a, while the distance R' is prepared for comparison with the depth D of the water bottom SB.

[0168] The detection result image generating means 17 uses the conversion table 17c to identify, for each pixel in the horizontal detection result image 22, the coordinates (R, θ) in the polar coordinate system corresponding to the coordinates (X, Y) of that pixel. Then, for each pixel, the detection result image generating means 17 identifies the level of the received signal at the position of the coordinates (R, θ) identified for that pixel from the received signal array 15a stored in the storage means 15 using the method described in the first embodiment, and sets the identified received signal level as the intensity of the reflected wave from the underwater position corresponding to that pixel. This allows the detection result image generating means 17 to identify, for each pixel in the horizontal detection result image 22, which shows the underwater detection result projected onto a plane parallel to the horizontal plane, the intensity of the reflected wave from the underwater position corresponding to that pixel, from the level of the received signal in the azimuth direction stored in the received signal array 15a. Up to this point, this is the same as in the first embodiment.

[0169] On the other hand, the detection result image generating means 17 of the ultrasonic sonar device 1 according to the second embodiment identifies, for each pixel of the horizontal detection result image 22, the polar coordinates (R, θ) corresponding to the coordinates (X, Y) of that pixel, and also identifies the distance R' from the wave transmitting and receiving unit 50 at the underwater position from the conversion table 17c. Then, the identified distance R' is compared with the depth D of the water bottom SB obtained by the water bottom depth determining means 16.

[0170] As a result, if the distance R' is less than the depth D of the water bottom SB, the pixel is determined to indicate a position shallower than the depth D of the water bottom SB, and a color is assigned using the first palette 17a to the intensity of the reflected wave from the underwater position identified for that pixel. On the other hand, if the distance R' is greater than the depth D of the water bottom SB, the pixel is determined to indicate a position deeper than the depth D of the water bottom SB, and a color is assigned using the second palette 17b to the intensity of the reflected wave from the underwater position identified for that pixel. In this way, the horizontal detection result image 22 shown in Figure 5 is generated in a single coordinate conversion process.

[0171] Next, details of the horizontal detection result image generating process in which the detection result image generating means 17 generates the horizontal detection result image 22 using the conversion table 17c explained above will be described with reference to FIG.

[0172] When the detection result image generation means 17 starts executing the horizontal detection result image generation process, it first obtains the depth D of the water bottom SB from the water bottom depth determination means 16 (S11). Next, the detection result image generation means 17 assigns -100 to X and -100 to Y as the initial values ​​of the Cartesian coordinates (X, Y) of the pixel whose color is to be specified (S12). As a result, in the following process, for the pixel specified by the Cartesian coordinates (-100, -100), first the intensity of the reflected wave from the underwater position corresponding to that pixel is specified, and then the color corresponding to the specified intensity of the reflected wave is specified for that pixel.

[0173] Next, the detection result image generating means 17 uses the conversion table 17c to identify the polar coordinates (R, θ) corresponding to the Cartesian coordinates (X, Y) set as the pixel specifying the color, and the distance R' from the wave transmitting and receiving unit 50 to the underwater position corresponding to that pixel (S13).The detection result image generating means 17 then compares the distance R' identified by the processing of S13 with the depth D of the water bottom SB obtained by the processing of S11 (S14).

[0174] As a result, if the distance R' is equal to or less than the depth D of the water bottom SB (S14: No), the detection result image generating means 17 determines that the pixel indicates a position shallower than the depth D of the water bottom SB, and sets the first palette 17a as a palette that assigns a color to the intensity of the reflected wave from the underwater position corresponding to the identified pixel (S15). For example, when using the palette shown in Figure 8, the first palette 17a is set by setting the most significant bit (MSB) of the relative address to "0".

[0175] On the other hand, if the comparison result in S14 shows that the distance R' is greater than the depth D of the water bottom SB (S14: Yes), the detection result image generating means 17 determines that the pixel indicates a position deeper than the depth D of the water bottom SB, and sets the second palette 17b as a palette that assigns a color to the intensity of the reflected wave from the underwater position corresponding to the identified pixel (S16). For example, when using the palette shown in Figure 8, the second palette 17b is set by setting the most significant bit (MSB) of the relative address to "1".

[0176] After processing S15 or S16, the detection result image generation means 17 identifies the intensity (7 bits) of the reflected wave at the underwater position corresponding to the Cartesian coordinates (X, Y) set as the pixel for specifying the color, using the polar coordinates (R, θ) identified by processing S13 and the received signal array 15a, using the method described above, and then assigns the color corresponding to the identified intensity of the reflected wave as the color of the pixel using the palette assigned by processing S15 or S16 (S17).

[0177] 8 is used, the detection result image generating means 17 determines an 8-bit relative address by adding the intensity of the reflected wave (7 bits) identified in the process of S17 to the lower-order bit of the most significant bit of the relative address set to "0" or "1" in the process of S15 or S16. Then, the detection result image generating means 17 reads out color information associated with the determined relative address and assigns the read-out color as the color of the pixel.

[0178] Next, the detection result image generating means 17 determines whether the X coordinate of the pixel whose color has been identified in the previous processing is less than "100" (S18), and if the result is that the X coordinate is less than "100" (S18: Yes), it adds 1 to the X coordinate (S19) and returns to the processing of S13. As a result, the Y coordinate remains unchanged, and the processing of S13 to S17 is executed for the pixel immediately adjacent in the positive direction of the X coordinate, and the color of that pixel is identified.

[0179] On the other hand, if the result of the determination in S18 is that the X coordinate is equal to or greater than "100" (S18: No), the detection result image generating means 17 then determines whether the Y coordinate of the pixel whose color has been identified in the previous processing is less than "100" (S20). As a result, if the Y coordinate is less than "100" (S20: Yes), 1 is added to the Y coordinate and -100 is assigned to the X coordinate (S21), and the processing returns to S13. As a result, the processing moves one row in the positive direction of the Y coordinate, and the processing of S13 to S17 is executed for the pixel whose X coordinate is -100, and the color of that pixel is identified.

[0180] Also, if the result of the judgment in S20 is that the Y coordinate is greater than or equal to "100" (S20: No), this means that the color has been identified for all pixels in one horizontal detection result image 22, and the horizontal detection result image generation process is terminated.

[0181] As described above, the ultrasonic sonar device 1 according to the second embodiment has the following advantages in addition to the advantages of the ultrasonic sonar device 1 according to the first embodiment.

[0182] (7) The received signals generated by the receiving units 13a-13g and the filter 14 for each direction of the first center axes C1a-C1f and the second center axis C2 are stored in the received signal array 15a of the storage means 15 in association with polar coordinates (R, θ) indicated by information θ indicating the direction and information R indicating the distance at which the reflected wave of the ultrasonic wave TB, which is the basis of the received signal, occurred. Meanwhile, the detection result image generation means 17 identifies each pixel of the horizontal detection result image 22 by orthogonal coordinates (X, Y). The detection result image generation means 17 also has a conversion table 17c that associates the orthogonal coordinates (X, Y) of each pixel with the corresponding polar coordinates (R, θ). This conversion table 17c also associates the orthogonal coordinates (X, Y) of each pixel with the distance R' from the wave transmitting and receiving unit 50 at the underwater position corresponding to the pixel indicated by the orthogonal coordinates (X, Y). The detection result image generating means 17 then identifies, for each pixel of the horizontal detection result image 22, the intensity of the reflected wave from an underwater position corresponding to that pixel, based on the received signal stored in the storage means 15 and associated with the polar coordinates (R, θ) corresponding to the pixel's Cartesian coordinates (X, Y) as specified by the conversion table 17c. The detection result image generating means 17 also determines whether the pixel is located shallower or deeper than the depth D of the water bottom SB based on the distance R' from the wave transmitting and receiving unit 50 to the underwater position corresponding to that pixel as specified by the conversion table 17c, and generates the horizontal detection result image 22 based on the result of that determination, assigning different colors to the intensity of the reflected wave from the underwater position corresponding to the identified pixel. This allows the horizontal detection result image 22 to be generated by a single coordinate conversion process using the conversion table 17c, with different colors assigned to positions within a predetermined range that are shallower than the depth D of the water bottom SB and positions within a predetermined range that are deeper than the depth D of the water bottom SB. Therefore, it is possible to generate a horizontal detection result image 22 that allows the user to easily distinguish the detection target GF and / or the water bottom SB while reducing the time required to generate the horizontal detection result image 22.

[0183] (8) The detection result image generating means 17 has a first palette 17a that defines colors to be assigned to the intensity of the reflected wave, and a second palette 17b that defines colors to be assigned to the intensity of the reflected wave as colors different from the colors defined in the first palette 17a. Then, for each pixel of the horizontal detection result image 22, the detection result image generating means 17 assigns a color to the intensity of the reflected wave from the underwater position corresponding to the identified pixel based on the distance R' from the wave transmitting and receiving unit 50 to the underwater position corresponding to the pixel specified by the conversion table 17c, using the first palette 17a if the pixel is located shallower than the depth D of the water bottom SB, and using the second palette 17b if the pixel is located deeper than the depth D of the water bottom SB. As a result, by simply changing the palette to be used based on the distance R' from the wave transmitting / receiving unit 50 at the underwater position corresponding to the pixel in a single coordinate conversion process using the conversion table 17c, it is possible to generate a horizontal detection result image 22 by assigning different colors to positions within a predetermined range that are shallower than the depth D of the water bottom SB and different colors to assign to positions within a predetermined range that are deeper than the depth D of the water bottom SB. Therefore, it is possible to easily generate a horizontal detection result image 22 that allows the user to easily distinguish the detection target GF and / or the water bottom SB while reducing the time required for generating the horizontal detection result image 22.

[0184] (Variation) Although the present invention has been described above based on the embodiments, it is readily apparent that the present invention is not limited to the above embodiments and that various improvements and modifications are possible within the scope of the present invention. For example, each embodiment may be modified by adding or replacing a part or parts of the configuration of another embodiment, including the modifications described below. Furthermore, the numerical values ​​given in the above embodiments are merely examples, and other numerical values ​​may of course be adopted.

[0185] In the above-described embodiments, the first transducers 52a to 52f are tilted and arranged with their acoustic radiation surfaces facing inward (toward the side where the second transducer 53 is located), but this is not necessarily limited to this, and the first transducers 52a to 52f may also be tilted and arranged with their acoustic radiation surfaces facing outward (toward 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 to C1f forms a predetermined angle ω 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° to 50°.

[0186] In each of the above embodiments, the case where the first oscillators 52a to 52f are arranged around the second oscillator 53 in the wave transmitting and receiving unit 50 has been described. However, the method of arranging the first oscillators 52a to 52f and the second oscillator 53 in the wave transmitting and receiving unit 50 may be arbitrary, from a broad perspective, as long as, 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 ω with respect to the second central axis C2 (in other words, the vertical direction), and the first central axes C1a to C1f are in a predetermined direction. For example, the first oscillators 52a to 52f and the second oscillator 53 may be arranged in one 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.

[0187] In the above-described embodiments, a first palette 17a is used to assign colors to reflected waves from positions shallower than the depth of the water bottom SB, and a second palette 17b is used to assign colors different from those specified in the first palette 17a to reflected waves from positions deeper than the depth of the water bottom SB. Alternatively, a common palette may be prepared, for example, using RGB to assign colors to the intensity of reflected waves regardless of the position at which the reflected waves are generated, and the same first transparency (first transmittance) value may be assigned to the intensity of reflected waves from positions shallower than the depth of the water bottom SB, and the same second transparency (second transmittance) value (however, the first transparency (first transmittance) and the second transparency (second transmittance) may be different values) may be assigned to the intensity of reflected waves from positions deeper than the depth of the water bottom SB. This also allows the ultrasonic sonar device 1 to generate a horizontal detection result image 22 by assigning different colors to positions within the specified range that are shallower than the depth of the bottom SB and different colors to positions within the specified range that are deeper than the depth of the bottom SB.

[0188] In each of the above embodiments, the bottom depth determination means 16 determines the depth of the bottom SB in the vertical direction directly below the ship 71, and the detection result image generation means 17 determines, based on the depth of the bottom SB in the vertical direction directly below the ship 71, whether the reflected wave of the ultrasonic wave TB is a reflection from a position shallower than the depth of the bottom SB or a reflection from a position deeper than the depth of the bottom SB. In contrast, if the detection range does not include the vertical direction of the ship 71, for example, in the case where the transmission / reception unit 50 shown in Figure 3 does not transmit ultrasonic waves TB from the second transducer 53 and the first transducers 52a to 52f each perform horizontal detection while transmitting and receiving ultrasonic waves TB so that their directional characteristics do not include the vertical direction, the bottom depth determination means 16 may determine the depth of the bottom SB in the direction of the first central axes C1a to C1f of the first transducers 52a to 52f, and the detection result image generation means 17 may determine, based on the depth of the bottom SB in the direction of the first central axes C1a to C1f, whether the reflected wave of the ultrasonic waves TB is reflected from a position shallower than the depth of the bottom SB or from a position deeper than the depth of the bottom SB.

[0189] In each of the above embodiments, a case has been described in which the color assigned to positions within the specified range that are shallower than the depth of the bottom SB in the horizontal detection result image 22 is always different from the color assigned to positions within the specified range that are deeper than the depth of the bottom SB. However, it is also possible to provide such a display mode and a display mode in which the color assigned to positions within the specified range that are shallower than the depth of the bottom SB and the color assigned to positions within the specified range that are deeper than the depth of the bottom SB are the same, and to allow the user to switch between these display modes by operating the operation button 31.

[0190] In each of the above embodiments, we have described a case where horizontal detection is performed by reducing the number of first transducers 52 in the transmitting and receiving unit 50 and simultaneously transmitting and receiving ultrasonic waves TB from the first transducers 52 over a predetermined range set in all directions of the ship 71.However, the present invention, in which the detection result image generating means 17 generates a horizontal detection result image 22 by assigning different colors to positions within the predetermined range that is the detection range that are shallower than the depth of the bottom SB and different colors to positions within the predetermined range that are deeper than the depth of the bottom SB, can also be applied to detection using PPI sonar or scanning sonar. [Explanation of symbols]

[0191] 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 Memory means 15a Received signal array 16 Bottom depth determination means 17 Detection result image generation means 17a First palette 17b Second palette 17c Conversion table 22 Horizontal detection result image 50 Transmission and reception wave unit 52 First oscillator 52a First oscillator 52b First oscillator 52c First oscillator 52d First oscillator 52e First oscillator 52f First oscillator 53 Second oscillator 71 Ship C1 Central axis C1a First central axis C1b First central axis C1c First central axis C1d First central axis C1e First central axis C1f First central axis C2 Second central axis D Depth of the water bottom E1a Directivity characteristic E1b Directivity characteristic E1d Directivity characteristic E1f Directivity characteristic GF Detection target object SB Water bottom TB Ultrasonic wave ω Angle

Claims

1. A wave transmitting / receiving unit attached to a vessel, configured to transmit ultrasonic waves over a predetermined range underwater and receive reflected waves of the ultrasonic waves reflected from each position underwater in each predetermined direction including at least a plurality of directions set in the azimuth 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 and receiving unit; a detection result image generating means for generating a detection result image showing the latest detection result in a color corresponding to the intensity of the reflected wave reflected from each position over the predetermined range, based on the reception signal for each of the predetermined directions generated by the reception signal generating means; and a water bottom depth determination means for determining the depth of the water bottom in the vertical direction directly below the vessel based on the intensity of the reflected wave received by the wave transmitting and receiving unit, The wave transmitting and receiving unit comprises: a plurality of first transducers each having a predetermined directional characteristic; each of the plurality of first transducers is fixed such that its central axis is in the predetermined direction and is positioned at a predetermined angle with respect to a vertical direction when the wave transmission / reception unit is attached to the ship, and has the predetermined directional characteristic so as to include at least the central axes of adjacent first transducers and the vertical direction; The detection result image generating means An ultrasonic sonar device characterized in that the detection result image is generated by assigning different colors to positions within the specified range that are shallower than the depth of the water bottom and to positions within the specified range that are deeper than the depth of the water bottom.

2. The ultrasonic sonar device of claim 1, characterized in that the detection result image generation means generates the detection result image by differentiating at least the brightness, saturation, hue, or transparency between the color assigned to a position within the specified range that is shallower than the depth of the water bottom and the color assigned to a position within the specified range that is deeper than the depth of the water bottom.

3. The detection result image generating means An ultrasonic sonar device as described in claim 1, characterized in that the detection result image covering the specified range is first generated in a color assigned to positions shallower than the depth of the water bottom, and then pixels at positions deeper than the depth of the water bottom are overwritten on the generated detection result image with the color assigned to positions deeper than the depth of the water bottom, and the overwritten detection result image is displayed.

4. a storage means for storing the reception signals generated by the reception signal generating means for each of the predetermined directions in association with polar coordinates indicated by information corresponding to the direction and information corresponding to the distance to a position where a reflected wave of the ultrasonic wave that is the source of the reception signal was generated; The detection result image generating means Identifying each pixel of the detection result image by Cartesian coordinates; a conversion table that associates the polar coordinates of each pixel with the distance from the wave transmitting / receiving unit to a position in water corresponding to the pixel, for each pixel's orthogonal coordinates; 2. The ultrasonic sonar device according to claim 1, wherein the detection result image is generated by determining, for each pixel of the detection result image, the intensity of the reflected wave from an underwater position corresponding to that pixel based on the received signal stored in the storage means and associated with polar coordinates corresponding to the orthogonal coordinates of the pixel specified by the conversion table, and determining whether the pixel is located shallower or deeper than the depth of the water bottom based on the distance from the wave transmitting and receiving unit to the underwater position corresponding to the pixel specified by the conversion table, and assigning different colors to the intensity of the reflected wave from the underwater position corresponding to the specified pixel based on the result of the determination.

5. The detection result image generating means a first palette that defines colors to be assigned to the intensities of reflected waves; a second palette that defines colors to be assigned to the intensities of reflected waves as colors different from the colors defined in the first palette, 5. The ultrasonic sonar device according to claim 4, wherein for each pixel of the detection result image, a color is assigned to the intensity of the reflected wave from the underwater position corresponding to the identified pixel based on the distance from the wave transmitting / receiving unit to the underwater position corresponding to the pixel identified by the conversion table, using the first palette if the pixel is located shallower than the depth of the water bottom, and using the second palette if the pixel is located deeper than the depth of the water bottom.

6. The wave transmitting and receiving unit comprises:

2. The ultrasonic sonar device according to claim 1, further comprising a second transducer fixed so that its central axis is positioned in the vertical direction when the sonar device is attached to the ship.

7. The ultrasonic sonar device according to claim 6, characterized in that the water bottom depth determination means determines the depth of the water bottom in the vertical direction directly below the ship based on the intensity of the reflected wave received by the second transducer after the ultrasonic wave is transmitted by the second transducer.

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