Ultrasonic sonar device

Abstract

An ultrasonic sonar device 1 includes a detection results image generation means 17 that generates a horizontal detection results image 22 that represents latest detection results in colors that correspond to the intensity of reflected waves reflected from each position within a prescribed range on the basis of a reception signal for reflected ultrasonic waves TB reflected from prescribed directions that include at least a plurality of directions set in azimuth directions. The detection results image generation means 17 generates the horizontal detection results image 22 such that the colors assigned to positions within the prescribed range that are shallower than the depth of a water bottom SB and the colors assigned to positions within the prescribed range that are deeper than the depth of the water bottom SB are different.

Description

Ultrasonic Sonar Device

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

[0002] There is known an ultrasonic sonar device that detects an object to be detected, such as a fish school, over a predetermined range in water by transmitting and receiving ultrasonic waves. A general fish school detection device detects an object to be detected in the vertical direction from a ship, whereas an ultrasonic sonar device can detect an object to be detected existing around the ship, such as horizontal detection or vertical cross-section detection. Here, horizontal detection is to detect an object to be detected included in a predetermined range, which is a direction obliquely downward from the horizontal plane as viewed from the ship, in all directions or some directions. As an ultrasonic sonar device for performing horizontal detection, for example, a PPI sonar (searchlight sonar) and a scanning sonar are known.

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

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

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

[0006] In such an ultrasonic sonar device, the transmitted ultrasonic waves are reflected not only from the object being detected but also from the seabed and other bodies of water, and these reflected waves are received. Figure 13 shows an example of a horizontal detection result image 122 displayed on a display device when horizontal detection is performed in a conventional ultrasonic sonar device. The horizontal detection result image 122 is a detection result image that shows the detection result of horizontal detection when an ultrasonic sonar device performs horizontal detection, by representing the intensity of the reflected ultrasonic waves reflected from each position with a color corresponding to that intensity. In the horizontal detection result image 122, the latest underwater detection results in each directional direction included in the detection range (predetermined range) are projected onto a plane parallel to the horizontal plane and shown as a circle (or a sector with a central angle at the position 172 of the ship) centered on the position 172 of the ship. As shown in Figure 13, the horizontal detection result image 122 displays not only the reaction of the detected object 122a due to the reflected ultrasonic waves from the detected object, but also the reaction of the seabed 122b due to the reflected ultrasonic waves from the seabed.

[0007] A problem with ultrasonic sonar devices was that it was difficult for users to easily distinguish between the detection target's response and the response of the seabed from the horizontal detection result image 122 displayed in this way. This problem was particularly pronounced when the detection target was located near the seabed. Furthermore, because the horizontal detection result image 122 is a projection of the detection results onto a plane parallel to the horizontal plane, it was difficult to obtain information about the depth of the location where the response occurred, which further made it difficult to distinguish between the detection target's response and the response of the seabed.

[0008] The present invention was made to solve the above-mentioned problems and aims to provide an ultrasonic sonar device that allows the user to easily identify the object to be detected and / or the seabed.

[0009] To achieve this objective, a first aspect of the present invention provides an ultrasonic sonar device comprising: a transmitter / receiver unit configured to transmit ultrasonic waves over a predetermined range in water and to receive reflected ultrasonic waves reflected from each position in the water for each predetermined direction including at least a plurality of directions set in the azimuth direction; a receiving signal generation means for generating a received signal for each predetermined direction based on the reflected waves received by the transmitter / receiver unit; a detection result image generation 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 predetermined direction generated by the receiving signal generation means; and a seabed depth determination means for determining the depth of the seabed based on the intensity of the reflected waves received by the transmitter / receiver unit, wherein the detection result image generation means generates the detection result image by assigning different colors to positions within the predetermined range that are shallower than the depth of the seabed and to positions within the predetermined range that are deeper than the depth of the seabed.

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

[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 a predetermined range using a color assigned to a position shallower than the depth of the seabed, and then overwrites the pixels at positions deeper than the depth of the seabed with the color assigned to a position deeper than the depth of the seabed, and displays the detection result image after overwriting.

[0012] A fourth aspect of the present invention is an ultrasonic sonar device according to the first or second aspect, comprising a storage means for storing the received signals generated by the receiving signal generation means for each predetermined direction, in association with polar coordinates indicated by information corresponding to that direction and information corresponding to the distance to the position where the reflected ultrasonic waves that form the basis of the received signals originated, wherein the detection result image generation means identifies each pixel of the detection result image in orthogonal coordinates, and comprises a conversion table that associates the orthogonal coordinates of each pixel with the corresponding polar coordinates and the distance from the transmitting / receiving unit at the underwater position corresponding to that pixel, For each pixel in the detection result image, the intensity of the reflected wave from the underwater location corresponding to that pixel is determined based on the received signal stored in the storage means, which is associated with the polar coordinates corresponding to the orthogonal coordinates of the pixel as determined by the conversion table. Furthermore, it is determined whether the pixel is located shallower or deeper than the depth of the seabed based on the distance from the transmitting / receiving unit at the underwater location corresponding to the pixel as determined by the conversion table. The detection result image is then generated by assigning different colors to the intensity of the reflected wave from the underwater location corresponding to the determined 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 generation 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 reflected waves from the underwater position corresponding to the specified pixel, based on the distance from the transmitting / receiving unit at the underwater position corresponding to the pixel, as specified by the conversion table, using the first palette if the pixel is at a position shallower than the depth of the seabed, and using the second palette if the pixel is at a position deeper than the depth of the seabed.

[0014] A sixth aspect of the present invention is an ultrasonic sonar device according to any of the first to fifth aspects, wherein the transmitting and receiving unit comprises a plurality of first transducers having predetermined directional characteristics, each of the plurality of first transducers having its central axis in the predetermined direction and fixed such that the central axis is at a predetermined angle with respect to the vertical when the transmitting and receiving unit is attached to a ship, and having the predetermined directional characteristics to include at least the central axis of an adjacent first transducer 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 comprises a second transducer fixed such 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 seabed depth determination means determines the vertical depth of the seabed based on the intensity of the reflected waves transmitted by the second transducer and received by the second transducer.

[0017] According to the ultrasonic sonar device of the first aspect of the present invention, a transmitting and receiving unit transmits ultrasonic waves into the water over a predetermined range, and reflected ultrasonic waves reflected from each position in the water are received for each predetermined direction, which includes at least a plurality of directions set in the azimuth direction. Based on the reflected waves received by the transmitting and receiving unit, a received signal is generated by a received signal generation means for each predetermined direction. Based on the received signals for each predetermined direction generated by the received signal generation means, a detection result image is generated by a detection result image generation means, which shows the latest detection result in a color corresponding to the intensity of the reflected waves reflected from each position over the predetermined range. From this detection result image, the user can determine the presence or absence of a target object and the direction and horizontal distance of the target object.

[0018] Here, the depth of the seabed is determined by the seabed depth determination means based on the intensity of the reflected waves received by the transmitting and 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 seabed depth and to positions within the predetermined range that are deeper than the seabed depth. As a result, the user can easily determine from the colors represented in the detection result image whether the reaction displayed in the image is a reaction from the detected object or a reaction from the seabed. Thus, the user has the effect of being able to easily distinguish between the detected object and / or the seabed.

[0019] The ultrasonic sonar device according to the second embodiment provides the following effects in addition to those of the ultrasonic sonar device according to the first embodiment. Specifically, the detection result image is generated by the detection result image generation means such that the brightness, saturation, hue, or transparency differs at least between the color assigned to a position shallower than the depth of the seabed and the color assigned to a position deeper than the depth of the seabed within a predetermined range. This makes it possible to clearly distinguish between the color assigned to the response from the detected object and the color assigned to the response from the seabed in the detection result image. Therefore, the user can easily distinguish between the detected object and / or the seabed.

[0020] The ultrasonic sonar device according to the third embodiment provides the following effects in addition to the effects of the ultrasonic sonar device according to the first or second embodiment. Specifically, the detection result image generation means first generates a detection result image over a predetermined range using a color assigned to positions shallower than the depth of the seabed. Then, the detection result image generation means overwrites the pixels at positions deeper than the depth of the seabed with a color assigned to those positions deeper than the depth of the seabed. The detection result image after this overwriting is then displayed. As a result, the detection result image generation process can be executed with a simple program structure, which has the effect of generating a detection result image that allows the user to easily identify the detected object and / or the seabed while keeping the memory capacity required for the program small.

[0021] The ultrasonic sonar device according to the fourth embodiment provides the following effects in addition to those of the ultrasonic sonar device according to the first or second embodiment. Specifically, the received signals generated by the received signal generation means for each predetermined direction are stored in the storage means in association with polar coordinates, which are indicated by information corresponding to the direction and information corresponding to the distance to the position where the reflected ultrasonic wave that forms the basis of the received signal originated. On the other hand, the detection result image generation means identifies each pixel of the detection result image in orthogonal coordinates. The detection result image generation means also has a conversion table that associates the polar coordinates corresponding to the orthogonal coordinates of each pixel. In this conversion table, the distance from the transmitting / receiving unit at the underwater position corresponding to the pixel indicated by the orthogonal coordinates is also associated with the orthogonal coordinates of each pixel. The detection result image generation means then identifies the intensity of the reflected wave from the underwater position corresponding to each pixel of the detection result image based on the received signal stored in the storage means, which is associated with the polar coordinates corresponding to the orthogonal coordinates of the pixel identified by the conversion table. Furthermore, the detection result image generation means determines whether the pixel is located at a depth shallower or deeper than the seabed based on the distance from the transmitting / receiving unit at the underwater location corresponding to the pixel identified by the conversion table. Based on this determination, a detection result image is generated while assigning different colors to the intensity of the reflected waves from the underwater location corresponding to the identified pixel. This makes it possible to generate a detection result image with different colors assigned to locations shallower than the seabed within a predetermined range and to locations deeper than the seabed within a predetermined range, all in a single coordinate transformation process using the conversion table. Therefore, it has the effect of generating a detection result image that allows the user to easily identify the object being detected and / or the seabed, while suppressing the time required to generate the detection result image.

[0022] The ultrasonic sonar device according to the fifth embodiment provides the following effects in addition to those of the ultrasonic sonar device according to the fourth embodiment. Specifically, the detection result image generation means has a first palette which defines the colors to be assigned to the intensity of reflected waves, and a second palette which defines the colors to be assigned to the intensity of reflected waves using colors different from those defined in the first palette. The detection result image generation means then assigns a color to the intensity of reflected waves from the underwater position corresponding to the identified pixel, based on the distance from the transmitting / receiving unit at the underwater position corresponding to the pixel, which is identified by a conversion table. This is done using the first palette if the pixel is at a position shallower than the depth of the seabed, and using the second palette if the pixel is at a position deeper than the depth of the seabed. This allows for the generation of detection result images by simply changing the palette used based on the distance from the transmitting / receiving unit at the underwater location corresponding to the pixel, using a single coordinate transformation process with a transformation table. This enables different colors to be assigned to locations shallower than the seabed within a predetermined range and to locations deeper than the seabed within the predetermined range. Therefore, it has the effect of easily generating detection result images that allow the user to easily identify the detected object and / or the seabed, while suppressing the time required to generate the detection result images.

[0023] The ultrasonic sonar device according to the sixth embodiment provides the following effects in addition to the effects of the ultrasonic sonar device according to any of the first to fifth embodiments. Specifically, each of the multiple first transducers is fixed in the transmitting and receiving unit such that its central axis is in a predetermined direction and, when the transmitting and receiving unit is attached to a ship, its central axis is at a predetermined angle with respect to the vertical direction. Each first transducer has predetermined directional characteristics that include at least the central axis of an adjacent first transducer and the vertical direction. As a result, ultrasonic waves can be transmitted simultaneously over a predetermined range with a small number of first transducers, and the reflected waves can be received to detect objects. Therefore, an ultrasonic sonar device capable of high-speed detection can be constructed at low cost. Here, since the first transducer also has directional characteristics in the vertical direction, it receives reflected waves from the seabed in the vertical direction before it receives reflected waves from the seabed in the direction of its own central axis. In detection result images, if the same color is assigned to responses from the detected object and responses from the seabed, it becomes difficult to grasp responses from the seabed in the vertical direction. In contrast, the detection result image generation means assigns different colors to positions within a predetermined range that are shallower than the seabed depth and to positions within a predetermined range that are deeper than the seabed depth, thereby generating the detection result image. This has the effect of allowing the user to easily determine responses from the seabed in the vertical direction in the detection result image.

[0024] The ultrasonic sonar device according to the seventh embodiment provides the following effects in addition to those of the ultrasonic sonar device according to the sixth embodiment. Specifically, in addition to the first transducer, a second transducer is provided on the transducer unit, which is fixed so that its central axis is located vertically when the transducer unit is attached to a ship. This has the effect of enabling detection of objects in the vertical direction and / or measurement of vertical depth with high accuracy.

[0025] The ultrasonic sonar device according to the eighth embodiment provides the following effects in addition to those of the ultrasonic sonar device according to the seventh embodiment. Specifically, ultrasonic waves are transmitted by a second transducer whose central axis is located in the vertical direction, and the depth of the seabed in the vertical direction is determined by a seabed depth determination means based on the intensity of the reflected waves received by the second transducer. This allows for a more accurate determination of the depth of the seabed in the vertical direction compared to determining the depth of the seabed in the vertical direction using a first transducer whose central axis is located at a predetermined angle with respect to the vertical direction. Therefore, the detection result image has the effect of clearly indicating to the user the response from the depth of the seabed in the vertical direction with high accuracy.

[0026] This is a schematic diagram illustrating the configuration of an ultrasonic sonar device according to a first embodiment of the present invention. This is a schematic diagram showing the state when a ship equipped with the ultrasonic sonar device performs underwater detection, viewed from the side. (a) is a schematic cross-sectional view showing the transducer unit of the ultrasonic sonar device, and (b) is a schematic perspective view showing the arrangement of a plurality of first transducers and second transducers constituting the transducer unit. (a) is a schematic diagram showing the first central axis of each of the first transducers when viewed vertically from above the ship, (b) is a schematic diagram showing the first central axis when viewed horizontally from the front of the ship, (c) is a schematic diagram showing the directional characteristics of the ultrasonic waves transmitted from the first transducers, and (d) is a diagram showing the directional characteristics of the ultrasonic waves transmitted from the first transducers when viewed from the front of the ship. This is a diagram showing an example of a display screen shown on the display device when the ultrasonic sonar device performs horizontal detection as a sonar function. This is a block diagram showing the electrical configuration of the ultrasonic sonar device. This figure schematically shows the contents of the received signal array stored in the storage means of the ultrasonic sonar device. This is a schematic figure schematically showing an example of the first palette and the second palette of the detection image generation means of the ultrasonic sonar device. This is a flowchart showing the horizontal detection result image generation process performed by the detection image generation means. This is a block diagram showing the electrical configuration of the ultrasonic sonar device according to the second embodiment of the present invention. This figure schematically shows the conversion table of the detection result image generation means of the ultrasonic sonar device. This is a flowchart showing the horizontal detection result image generation process performed by the detection image generation means. This figure shows an example of a horizontal detection result image displayed on a display device when horizontal detection is performed in a conventional ultrasonic sonar device.

[0027] Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings. The embodiments described below are all preferred specific examples of the present invention. Therefore, the numerical values, shapes, materials, components, arrangement positions of components, and connection configurations shown in the following embodiments are examples and are not intended to limit the present invention. Accordingly, among the components in the following embodiments, those not described in the independent claims representing the highest-level concept of the present invention will be described as optional components. Furthermore, in each figure, substantially identical components are denoted by the same reference numerals, and redundant explanations are omitted or simplified.

[0028] (First Embodiment) First, an ultrasonic sonar device 1 according to the first embodiment, which is one embodiment of the present invention, will be described with reference to Figures 1 to 9. Figure 1 is a schematic diagram showing the configuration of the ultrasonic sonar device 1, and Figure 2 is a schematic diagram showing the state when underwater detection is performed by a ship 71 equipped with the ultrasonic sonar device 1, viewed from the side.

[0029] As shown in Figures 1 and 2, the ultrasonic sonar device 1 is mounted on a vessel 71 and has at least a sonar function that horizontally detects objects GF such as schools of fish in the water such as the sea, lake, or river in which the vessel 71 is floating, over a predetermined range around the vessel 71. Horizontal detection is performed by detecting objects GF that are included in a predetermined range that is diagonally downward from the horizontal plane as viewed from the vessel 71 and covers all directions in the azimuth direction.

[0030] In this embodiment, the predetermined range in which horizontal detection is performed is described as being omnidirectional with respect to the azimuth direction as viewed from the vessel 71. However, it is not necessarily required to be omnidirectional, and it may be limited to a portion of the azimuth direction as viewed from the vessel 71. Furthermore, the ultrasonic sonar device 1 may have a sonar function that performs vertical cross-sectional detection in addition to horizontal detection, or it may have a fish finder function that detects objects GF located in the vertical direction directly below the vessel 71 and displays the detection results in chronological order.

[0031] The ultrasonic sonar device 1 comprises a main body 5, an operation button 31 provided on the main body 5, a display device 21 integrally formed on the main body 5 as a display means, a transmitter / receiver unit 50 for transmitting and receiving ultrasonic waves TB for detecting a target object GF, and a lifting device 41 for raising and lowering the transmitter / receiver unit 50. The main body 5, the operation button 31, and the display device 21 are located in the wheelhouse of the ship 71, while the transmitter / receiver unit 50 and the lifting device 41 are located in the bottom of the ship 71. The transmitter / receiver unit 50 can be raised and lowered by the lifting device 41, allowing it to extend and retract from the bottom of the ship 71 into the water. The ultrasonic sonar device 1 does not necessarily have to have the lifting device 41, and the transmitter / receiver unit 50 may be fixed to the ship 71 in a position where ultrasonic waves TB can be transmitted and received toward the water.

[0032] The operation button 31 is a button that can be operated by the user, and is used when the user gives various instructions or settings to the ultrasonic sonar device 1. For example, the user can turn the power of the ultrasonic sonar device 1 on or off, set the detection mode (horizontal detection, vertical cross-sectional detection, fish detection, etc.) and detection range of the ultrasonic sonar device 1, and set the type and brightness of the image displayed by the display device 21, etc., by operating the operation button 31.

[0033] As shown in Figure 2, the ultrasonic sonar device 1 transmits (irradiates) ultrasonic waves TB in a conical shape over a predetermined range from the transmitting / receiving unit 50, with the transmitting / receiving unit 50 protruding from the bottom of the ship 71. The transmitting / receiving unit 50 is configured to receive reflected ultrasonic waves TB reflected from objects to be detected GF, or from the seabed or lakebed (hereinafter collectively referred to as "seabed SB"), etc., within that predetermined conical range. The detailed configuration of the transmitting / receiving unit 50 will be described later with reference to Figures 3 and 4.

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

[0035] Next, the detailed configuration of the transmitting / receiving unit 50 will be described with reference to Figures 3 and 4. Figure 3(a) is a schematic cross-sectional view showing the transmitting / receiving unit 50, and Figure 3(b) is a schematic perspective view showing the arrangement of the multiple first transducers 52 (52a to 52f) and the second transducer 53 that constitute the transmitting / receiving unit 50.

[0036] Furthermore, Figure 4(a) schematically shows the first central axes C1a to C1f of the first transducers 52a to 52f as viewed vertically from above the ship 71, and Figure 4(b) schematically shows the first central axes C1a to C1f of the first transducers 52a to 52f as viewed horizontally from the front side of the ship 71. Furthermore, Figure 4(c) schematically shows the directional characteristics E1a, E1b, and E1f of the ultrasonic TB transmitted from adjacent first transducers 52a, 52b, and 52f, and Figure 4(d) shows the directional characteristics E1a and E1d of the ultrasonic TB transmitted from the first transducer 52a and the first transducer 52d as viewed from the front side of the ship 71.

[0037] As shown in Figure 3, the transmitting and receiving unit 50 has a structure in which a plurality of (six in the example shown in Figure 3) first transducers 52 (first transducer 52a, first transducer 52b, first transducer 52c, first transducer 52d, first transducer 52e, first transducer 52f) and a second transducer 53 are housed in a case 51 and molded. Each first transducer 52 is a disc-shaped structure having the same size and shape as the others. The second transducer 53 also has a disc shape similar to the first transducers 52. However, the size of the second transducer 53 is determined according to the required characteristics. That is, the second transducer 53 may be the same size as the first transducer 52, or it may be a different size from the first transducer 52.

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

[0039] The piezoelectric element 55 is a plate-shaped object made of piezoelectric ceramics, and for example, a disc-shaped plate-shaped object made of lead zirconate titanate (PZT) is used. The piezoelectric element 55 has a front side electrode (not shown) formed on the front surface, which is fully bonded to the substrate 54 via an adhesive layer (not shown), and a back side electrode (not shown) formed on the back surface facing the front surface. Lead wires are electrically connected to the front side electrode and the back side electrode, respectively.

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

[0041] Further, when the base material 54 vibrates due to the reflected wave of the ultrasonic TB, each of the first vibrator 52 and the second vibrator 53 causes the piezoelectric element 55 to deform due to the vibration, and a voltage is generated between the front-side electrode and the back-side electrode. The first vibrators 52a to 52f and the second vibrator 53 output the voltage generated between the front-side electrode and the back-side electrode to the corresponding reception units 13a to 13g described later, respectively, thereby generating reception signals corresponding to the reflected waves received by the respective first vibrators 52a to 52f and the second vibrator 53.

[0042] The case 51 has an opening at one end, and a plurality of first vibrators 52 and second vibrators 53 are housed in the case 51. The second vibrator 53 is disposed at the center of the case 51. Further, six first vibrators 52 are arranged around the second vibrator 53 in the counterclockwise order of the first vibrator 52a, the first vibrator 52b, the first vibrator 52c, the first vibrator 52d, the first vibrator 52e, and the first vibrator 52f as viewed from the front side of the base material 54. The acoustic radiation surfaces formed on the front surfaces of the base materials 54 of the respective 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 one virtual spherical surface.

[0043] In the present embodiment, the number of the first vibrators 52 is six. However, the number of the first vibrators 52 may be any number of three or more, preferably four or more, and more preferably six or more. However, when the number of the first vibrators 52 increases, the configuration of the ultrasonic sonar device 1 becomes complicated and the device becomes large-sized and expensive. Therefore, the number of the first vibrators 52 is preferably ten or less, and more preferably eight or less.

[0044] Here, for the first vibrator 52a, it can be understood that the direction of the first central axis C1a, which is the central axis perpendicular to the front surface (acoustic radiation surface) of the base material 54 (which can also be said to be the direction of the normal vector of the first vibrator 52a), is the acoustic radiation direction. Similarly to the first vibrator 52a, the first central axis C1b is defined for the first vibrator 52b, the first central axis C1c is defined for the first vibrator 52c, the first central axis C1d is defined for the first vibrator 52d, the first central axis C1e is defined for the first vibrator 52e, and the first central axis C1f is defined for the first vibrator 52f. And it can be understood that each of the first central axes C1b to C1f is the acoustic radiation direction of the corresponding first vibrators 52b to 52f.

[0045] Also, for the second vibrator 53, it can be understood that the direction of the second central axis C2, which is the central axis perpendicular to the front surface (acoustic radiation surface) of the base material 54 (which can also be said to be the direction of the normal vector of the second vibrator 53), is the acoustic radiation direction.

[0046] That is, the first central axes C1a to C1f of each of the first vibrators 52a to 52f and the second central axis C2 of the second vibrator 53 are the predetermined directions for transmitting the ultrasonic wave TB to a predetermined range, which is the detection range of the detection target GF, and receiving the reflected wave thereof.

[0047] Here, the wave transmitting / receiving unit 50 is attached to the ship 71 such that the direction of the second central axis C2 of the second vibrator 53 becomes the vertical direction. That is, the second vibrator 53 transmits (irradiates) the ultrasonic wave TB in the vertical direction directly below the ship 71. Due to the presence of this second vibrator 53, the ultrasonic sonar device 1 can 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 directivity characteristic of the ultrasonic wave TB transmitted from the second vibrator 53 preferably has a small directivity angle and a narrow beam shape. Thereby, 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 can be further improved.

[0048] On the other hand, in the transmitting and receiving unit 50, as shown in Figure 3, the first transducers 52a to 52f are arranged with their acoustic radiation surfaces tilted such that the first central axes C1a to C1f form a predetermined angle ω with respect to the second central axis C2 (i.e., the vertical direction when the transmitting and receiving unit 50 is attached to the ship 71). As a result, the acoustic radiation direction of each of the first transducers 52a to 52f is oriented in a direction different from the vertical direction directly below the ship 71, as shown in Figure 4(b).

[0049] In this embodiment, each of the first transducers 52a to 52f is inclined so that their acoustic radiating surfaces face inward (towards the side where the second transducer 53 is located) (see Figure 3). In this case, each of the first central axes C1a to C1f is preferably at a predetermined angle ω with respect to the second central axis C2, selected from a range of 20° to 50°. In this embodiment, the predetermined angle ω is 30°. As shown in Figure 3(a), each of the first central axes C1a to C1f and the second central axis C2 are converged at a single point.

[0050] Furthermore, the first central axes C1a to C1f of the first transducers 52a to 52f are arranged at equal intervals in the azimuthal direction, as shown in Figure 4(a), so that the angles between adjacent first central axes C1a to C1f are the same angle δ when viewed vertically from above the ship 71 with the transmitting and receiving unit 50 attached to the ship 71. When there are n first transducers 52, the angle δ is (360 / n)° (when there are 6 first transducers 52, the angle δ is 60°).

[0051] As a result, the transmitting and receiving unit 50 can simultaneously transmit ultrasonic waves TB in each predetermined direction indicated by the first central axis C1a to C1f, using at least the first transducers 52a to 52f, over a predetermined range set in all directions of the ship 71, and can also receive reflected waves in each of those predetermined directions.

[0052] In this embodiment, as shown in Figures 4(a) and (b), when viewing the ship 71 from above in a vertical direction, the first central axis C1a is oriented to the right with respect to the front-to-back direction of the ship 71, and the first central axes C1b to C1f are arranged in order counterclockwise from the first central axis C1a at intervals of angle δ. In this embodiment, an example is shown in which the first transducers 52a to 52f are arranged so that their respective first central axes C1a to C1f are evenly spaced in the azimuthal direction. However, it is sufficient that the ultrasonic TB can be transmitted simultaneously by at least the first transducers 52a to 52f in each predetermined direction indicated by the first central axes C1a to C1f over a predetermined range set in all directions of the ship 71, and there may be variations in the spacing of the first central axes C1a to C1f. The directions of the first central axes C1a to C1f set as described above correspond to the "multiple directions set in the azimuth direction" of the present invention.

[0053] The directional characteristics of the ultrasonic TB transmitted from each of the first transducers 52a to 52f are set to include the first central axes C1a to C1f of the adjacent first transducer 52. For example, as shown in Figure 4(c), the directional characteristic E1a of the ultrasonic 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 characteristics E1b of the ultrasonic TB transmitted from the first transducer 52b and the directional characteristics E1f of the ultrasonic TB transmitted from the first transducer 52f are set to include the first central axis C1a of the first transducer 52a. Although not shown in the figures, the directional characteristics E1b of the ultrasonic TB transmitted from the first transducer 52b are also set to include the first central axis C1c of the first transducer 52c adjacent on the opposite side from the first transducer 52a, and the directional characteristics E1f of the ultrasonic TB transmitted from the first transducer 52f are also set to include the first central axis C1e of the first transducer 52e adjacent on the opposite side from the first transducer 52a.

[0055] Furthermore, as shown in Figure 4(d), the directional characteristics E1a of the ultrasonic TB transmitted from the first transducer 52a and the directional characteristics E1d of the ultrasonic TB transmitted from the first transducer 52d both include the vertical direction when the transmitting / receiving unit 50 is mounted on the ship 71. Although not shown, the directional characteristics of the ultrasonic TB transmitted from the first transducers 52b, 52c, 52e, and 52f are also set to include the vertical direction when the transmitting / receiving unit 50 is mounted on the ship 71, similar to the first transducers 52a and 52d.

[0056] As described above, the ultrasonic TB transmitted from each of the first transducers 52a to 52f is set to have directional characteristics that include the first central axes C1a to C1f of adjacent first transducers 52, and also include the vertical direction when the transmitting / receiving unit 50 is attached to the ship 71. As a result, the transmitting / receiving unit 50 drives each of the first transducers 52a to 52f simultaneously, so that ultrasonic TB is irradiated from each of the first transducers 52a to 52f in the direction of their respective first central axes C1a to C1f, and the directional characteristics of the ultrasonic TB allow the ultrasonic TB to be transmitted simultaneously to a predetermined range set in all directions of the ship 71 with a small number of first transducers 52.

[0057] Furthermore, each of the first transducers 52a to 52f has a fixed direction of the first central axis C1a to C1f and a fixed directional characteristic of the ultrasonic TB emitted from each of the first transducers 52a to 52f, so that ultrasonic TB is irradiated from the transmitting / receiving unit 50 over a predetermined range. Therefore, circuits for controlling the direction of the first central axis C1a to C1f in the first transducers 52a to 52f, and circuits for controlling the directional characteristic of the ultrasonic TB emitted from each of the first transducers 52a to 52f, can be eliminated.

[0058] Furthermore, the transmitting and receiving unit 50 can receive the reflected waves of ultrasonic waves TB reflected from the object GF to be detected within a predetermined range, for each of the first central axes C1a to C1f, which are in a predetermined direction, using the first transducers 52a to 52f corresponding to each of the first central axes C1a to C1f. As a result, the ultrasonic sonar device 1 can be constructed to perform high-speed detection in a compact and low-cost manner.

[0059] The transmitting and receiving unit 50 is arranged and housed in a case 51 with the first transducers 52a to 52f and the second transducer 53 closely packed together, such that the first central axes C1a to C1f and the second central axis C2 are oriented in the directions described above, and are fixed in place with a filler. The filler used is a resin material (for example, urethane resin) that has a lower inherent acoustic impedance than the base material 54, which is the acoustic matching layer of the first transducer 52 and the second transducer 53, and is waterproof. The outer surface of the filler is filled so that it is flush with the opening of the case 51, thereby closing the opening of the case 51.

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

[0061] As shown in Figure 5, when the ultrasonic sonar device 1 performs horizontal detection as a sonar device, the display device 21 mainly displays the horizontal detection result image 22. In addition, when the ultrasonic sonar device 1 performs horizontal detection, it may also display one or more detection result images on the display device 21, in addition to the horizontal detection result image 22, which are time-series images of detection results in the distance direction from the transmitting / receiving unit 50 based on a received signal in at least one direction (in the example in Figure 5, this applies to each of the two detection result images displayed vertically in the left area of ​​the display device 21). Furthermore, detection result images other than the horizontal detection result image 22 may be displayed or hidden on the display device 21 by the user operating the operation button 31.

[0062] The horizontal detection result image 22 is a detection result image that shows the latest detection results in a horizontal detection performed diagonally downward from the ship 71 in all directions (or some directions), with the colors corresponding to the intensity of the reflected ultrasonic TB waves reflected from each position within a predetermined detection range. In the horizontal detection result image 22, the latest underwater detection results for each direction included in the predetermined range are shown as circles (or sectors with a central angle at the position 72 of the ship 71) centered on the position 72 of the ship 71, projected onto a plane parallel to the horizontal plane. 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 (hereinafter also referred to as "underwater detection results projected onto a plane parallel to the horizontal plane") over a predetermined range set in all directions of the ship 71 are displayed on the display device 21 as the horizontal detection result image 22 projected onto a plane parallel to the horizontal plane.

[0063] As described above, when ultrasonic TB is transmitted from the transmitting / receiving unit 50 over a predetermined range, the ultrasonic TB is reflected from the object GF to be detected within that predetermined range. The response 22a based on the reflected wave from the object GF (hereinafter referred to as "object GF response 22a") is displayed in the horizontal detection result image 22. In addition, ultrasonic TB is also reflected from the seabed SB, and the response 22b based on the reflected wave from the seabed SB (hereinafter referred to as "seabed SB response 22b") is also displayed in the horizontal detection result image 22.

[0064] In this embodiment, the ultrasonic sonar device 1 generates a horizontal detection result image 22, and the colors assigned according to the intensity of the reflected waves from the object GF (colors defined in the first palette 17a described later) and the colors assigned according to the intensity of the reflected waves from the seabed SB (colors defined in the second palette 17b described later) are different. For example, this allows the user of the ultrasonic sonar device 1 to easily determine from the colors represented in the horizontal detection result image 22 whether the reaction displayed in the horizontal detection result image 22 is the reaction 22a of the object GF or the reaction 22b of the seabed SB. Therefore, the user can easily distinguish between the object GF and / or the seabed SB.

[0065] In this case, for example, the color assigned according to the intensity of the reflected wave from the object GF may be a light color, and the color assigned according to the intensity of the reflected wave from the seabed SB may be a dark color. Alternatively, the color assigned according to the intensity of the reflected wave from the object GF may be a highly saturated color, and the color assigned according to the intensity of the reflected wave from the seabed SB may be a less saturated color. Furthermore, the color assigned according to the intensity of the reflected wave from the object GF may be a low transparency (transmittance) color, and the color assigned according to the intensity of the reflected wave from the seabed SB may be a highly transparency (transmittance) color.

[0066] These features allow for a clear distinction between the color assigned to the reaction 22a of the detected object GF and the color assigned to the reaction 22b of the seabed SB. Furthermore, the reaction 22a of the detected object GF can be emphasized and communicated to the user, making the reaction 22b of the detected object GF more easily noticeable and drawing the user's attention.

[0067] Furthermore, the relationship between the brightness, saturation, or transparency (transmittance) of the color assigned according to the intensity of the reflected waves from the object GF and the color assigned according to the intensity of the reflected waves from the seabed SB may be reversed from the above. This also makes it possible to clearly differentiate the color assigned to the reaction 22a of the object GF and the color assigned to the reaction 22b of the seabed SB, and to emphasize the reaction 22b of the seabed SB to the user, thereby making the seabed SB easier to understand and to draw the user's attention.

[0068] Furthermore, the hue may be different for the color assigned according to the intensity of the reflected wave from the object GF and the color assigned according to the intensity of the reflected wave from the seabed SB. This also makes it possible to clearly differentiate the color assigned to the reaction 22a of the object GF and the color assigned to the reaction 22b of the seabed SB.

[0069] Furthermore, the user may set, by operating the operation button 31, whether or not to use different colors for the color assigned according to the intensity of the reflected waves from the object GF and the color assigned according to the intensity of the reflected waves from the seabed SB. This allows the ultrasonic sonar device 1 to allow the user to choose whether or not to display the reaction 22a of the object GF and the reaction 22b of the seabed SB in different colors in the horizontal detection result image 22.

[0070] The determination of whether the received ultrasonic TB reflected wave is due to reflection from the target object GF or from the seabed SB is made based on the distance from the transmitting / receiving unit 50 to the location where the reflection of the ultrasonic TB wave occurred, and the depth of the seabed SB determined by the seabed depth determination means 16, which will be described later.

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

[0072] Furthermore, if the distance to the location where the reflected ultrasonic wave TB occurred is less than the depth of the seabed SB determined by the seabed depth determination means 16, the reflected ultrasonic wave TB can be determined to be due to reflection from the object GF being detected. Also, if the distance to the location where the reflected ultrasonic wave TB occurred is greater than or equal to the depth of the seabed SB determined by the seabed depth determination means 16, the reflected ultrasonic wave TB can be determined to be due to reflection from the seabed SB.

[0073] Furthermore, all reflected ultrasonic TB waves received after the ultrasonic TB reflected from the seabed SB is received by the transmitting / receiving unit 50 are actually all reflected from the seabed SB. However, the ultrasonic sonar device 1 treats the reflected waves as being received from deeper locations (farther distances) as time elapses since the ultrasonic TB was transmitted. In other words, reflected ultrasonic TB waves received after the ultrasonic TB reflected from the seabed SB is first received by the transmitting / receiving unit 50 are considered to have been reflected from a location deeper than the depth of the seabed SB. Therefore, in this invention, the horizontal detection result image 22 is generated assuming the existence of reflected ultrasonic TB waves reflected from a location deeper than the depth of the seabed SB, but in reality, these reflected waves are reflected from the seabed SB.

[0074] Next, the electrical configuration of the ultrasonic sonar device 1 will be described with reference to Figure 6. Figure 6 is a block diagram showing the electrical configuration of the ultrasonic sonar device 1. Inside the main body 5 of the ultrasonic sonar device 1 is a control device 10, which is equipped with transmitting units 11a, 11b, diodes 12a to 12g, receiving units 13a to 13g, a filter 14, storage means 15, seabed 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, seabed depth determination means 16, detection result image generation means 17, and display control means 18 may be configured as hardware, implemented as software, or implemented through the cooperation of hardware and software.

[0076] Although not shown in the diagram, the control device 10 includes a CPU (Central Processing Unit), a flash memory (a rewritable, non-volatile memory) and / or a ROM (Read Only Memory) (a non-rewritable, non-volatile memory) that stores programs executed by the CPU and fixed values ​​referenced by those programs, and a RAM (Random Access Memory) (a read-write, volatile memory) that temporarily stores various data when the CPU executes a program. These are connected via a bus line.

[0077] Of the transmitting units 11a, 11b, receiving units 13a to 13g, filter 14, seabed depth determination means 16, detection result image generation means 17, and display control means 18, the parts implemented by software or through the cooperation of hardware and software are implemented by the CPU executing a program. The storage means 15 is built into RAM.

[0078] Based on instructions from the CPU, the transmitting unit 11a generates a single drive signal to transmit ultrasonic TB from the first transducers 52a to 52f. The output of the single drive signal generated by the transmitting unit 11a is branched between the transmitting unit 11a and diodes 12a to 12f and distributed to each of the first transducers 52a to 52f. Specifically, one branch is input to the first transducer 52a via diode 12a, one via diode 12b to the first transducer 52b, one via diode 12c to the first transducer 52c, one via diode 12d to the first transducer 52d, one via diode 12e to the first transducer 52e, and one via diode 12f to the first transducer 52f.

[0079] Diodes 12a to 12f each allow the drive signal generated by the transmitting unit 11a to pass through and input to the corresponding first oscillators 52a to 52f, and are also elements that block the signal (voltage) generated by receiving the reflected wave in each of the first oscillators 52a to 52f from being transmitted to the transmitting unit 11a or to the branching point of the drive signal output from the transmitting unit 11a to each of the first oscillators 52a to 52f.

[0080] A single drive signal generated by the transmitting unit 11a is branched and input to the first transducers 52a to 52f via diodes 12a to 12f. As a result, each of the first transducers 52a to 52f, which have the same shape and size, are driven simultaneously and can output ultrasonic TB of the same intensity at the same timing. Therefore, ultrasonic TB can be transmitted uniformly in a predetermined direction (i.e., the direction of the first central axis C1a to C1f) within a predetermined range set in all directions relative to the ship 71, making the detection sensitivity uniform in all predetermined directions.

[0081] Furthermore, since one transmitting unit 11a is provided for multiple first transducers 52a to 52f, significant cost reduction and miniaturization can be achieved compared to the case where each first transducer 52a to 52f has its own transmitting unit 11a.

[0082] Furthermore, diodes 12a to 12f are provided at the downstream side of the branching point between the transmitting unit 11a and each of the first transducers 52a to 52f, where the drive signal output from the transmitting unit 11a branches out toward each of the first transducers 52a to 52f. This prevents the signals (voltages) output by each of the first transducers 52a to 52f upon receiving the reflected waves of the ultrasonic TB from flowing back to the transmitting unit 11a or from interfering with the signal lines of other first transducers 52a to 52f via the branching point. Therefore, even if one transmitting unit 11a is provided for multiple (six) first transducers 52a to 52f, the independence of the signals (voltages) output from each of the first transducers 52a to 52f can be ensured.

[0083] The transmitting unit 11b generates a drive signal to transmit ultrasonic TB from the second transducer 53 based on instructions from the CPU. The output of the drive signal generated by the transmitting unit 11b is input to the second transducer 53 via the diode 12g. The diode 12g is an element that allows the drive signal generated by the transmitting unit 11b to pass through and input to the second transducer 53, and also blocks the signal (voltage) generated when the second transducer 53 receives the reflected wave from being transmitted to the transmitting unit 11b. This diode 12g prevents the signal (voltage) output by the second transducer 53 when it receives the reflected wave of ultrasonic TB from flowing back to the transmitting unit 11b.

[0084] The ultrasonic sonar device 1 is provided with a transmitting unit 11b that generates a drive signal for the second transducer 53, which transmits ultrasonic TB in the vertical direction directly below the ship 71, independently of the transmitting unit 11a that generates drive signals for the first transducers 52a to 52f. This allows the ultrasonic sonar device 1 to function as a normal fish finder by turning off the transmission of ultrasonic TB from the first transducers 52a to 52f and transmitting ultrasonic TB only from the second transducer 53, or to control the transmission of ultrasonic TB from the second transducer 53 independently of the transmission of ultrasonic TB from the first transducers 52a to 52f when performing horizontal detection as a sonar function.

[0085] In this embodiment, a transmitting unit 11a corresponding to the first transducers 52a to 52f and a transmitting unit 11b corresponding to the second transducer 53 are provided separately. However, if the specifications of the ultrasonic sonar device 1 allow for the transmission of ultrasonic TB from the second transducer 53 to always occur at the same timing as the first transducers 52a to 52f, then only one transmitting unit 11a may be provided for the first transducers 52a to 52f and the second transducer 53, and a single drive signal may be generated from this transmitting unit 11a. This would allow for further significant cost reduction and miniaturization of the ultrasonic sonar device 1.

[0086] Receiving units 13a to 13g are provided for each of the multiple (six) first transducers 52a to 52f and second transducer 53. At predetermined time intervals after the corresponding first transducers 52a to 52f and second transducers 53 transmit ultrasonic TB, receiving units 13a to 13g capture signals (voltages) output according to the intensity of the reflected ultrasonic TB received by the first transducers 52a to 52f and second transducers 53, and perform sampling by applying predetermined processing to the captured signals.

[0087] Specifically, receiving unit 13a is connected to the first transducer 52a and receives a signal (voltage) output according to the intensity of the reflected wave received by the first transducer 52a, and performs predetermined processing. Similarly, receiving unit 13b is connected to the first transducer 52b, receiving unit 13c is connected to the first transducer 52c, receiving unit 13d is connected to the first transducer 52d, receiving unit 13e is connected to the first transducer 52e, receiving unit 13f is connected to the first transducer 52f, and receiving unit 13g is connected to the second transducer 53. Each receiving unit 13b to 13g also receives a signal (voltage) output according to the intensity of the reflected wave received by the connected first transducers 52b to 52f or the second transducer 53, and performs predetermined processing.

[0088] Each receiving unit 13a to 13g has an amplification circuit and an analog-to-digital conversion circuit. Each receiving unit 13a to 13g samples the signal (voltage) output from the corresponding first transducer 52a to 52f or second transducer 53 at predetermined intervals after the ultrasonic TB has been transmitted from the corresponding first transducer 52a to 52f or second transducer 53. Specifically, at predetermined intervals, as a predetermined process, each receiving unit 13a to 13g amplifies the signal (voltage) acquired from the corresponding first transducer 52a to 52f or second transducer 53 using an amplification circuit, and then converts it into a digital signal (digital value) of a predetermined number of bits (7 bits in this embodiment) using an analog-to-digital conversion circuit (AD conversion circuit).

[0089] Then, the receiving unit 13a outputs the digital signal obtained by the AD conversion circuit to the filter 14 as the received signal (received signal of the reflected wave of the ultrasonic TB) received by the first transducer 52a. Similarly, the receiving unit 13b outputs the digital signal obtained by the respective AD conversion circuit to the filter 14 as the received signal of the first transducer 52b, the receiving unit 13c outputs the digital signal obtained by the first transducer 52c, the receiving unit 13d outputs the digital signal obtained by the first transducer 52d, the receiving unit 13e outputs the digital signal obtained by the first transducer 52e, the receiving unit 13f outputs the digital signal obtained by the first transducer 52f, and the receiving unit 13g second transducer 53.

[0090] As described above, one transmitting unit 11a is provided for each of the multiple (six) first transducers 52a to 52f to reduce costs and miniaturize the device. In contrast, by providing a receiving unit 13a to 13f for each of the multiple first transducers 52a to 52f, the independence of the signals (voltages) output from each of the first transducers 52a to 52f can be maintained while applying predetermined processing to each signal (voltage). On the other hand, since the ultrasonic sonar device 1 has fewer transducers than conventional scanning sonars, even if a receiving unit 13a to 13f is provided for each of the first transducers 52a to 52f, the overall receiving unit can be made smaller and costs can be reduced compared to conventional scanning sonars.

[0091] The received signals output from the receiving units 13a to 13g are original received signals that represent the raw intensity values ​​of the reflected ultrasonic TB waves received by the corresponding first transducers 52a to 52f and the second transducer 53, respectively. This means that the original received signals are the received signals before filtering by the filter 14, which will be described next.

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

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

[0094] Here, the azimuth direction is the direction in which the first central axes C1a to C1f of the first transducers 52a to 52f, that is, the direction in which their respective acoustic radiation directions are aligned, or in other words, the circumferential direction centered on the ship 71. The distance direction is the direction in which the ultrasonic TB is transmitted at the first central axes C1a to C1f of the first transducers 52a to 52f, and at the second central axis C2 of the second transducer 53, that is, the respective acoustic radiation directions themselves.

[0095] Furthermore, when the ultrasonic sonar device 1 performs horizontal detection using its sonar function, it uses a small number of transducers (six in this embodiment), namely the first transducers 52a to 52f, which significantly reduces the azimuth resolution. Therefore, in horizontal detection, the filter 14 may set a virtual direction at an intermediate position between adjacent first central axes C1a to C1f of the first transducers 52a to 52f, which are predetermined directions in which ultrasonic TB is transmitted and received, and generate a virtual received signal from the received signals of the first transducers 52a to 52f, assuming that ultrasonic TB is virtually transmitted and received in that virtual direction.

[0096] By generating a virtual received signal in a virtual direction, the number of directions in which ultrasonic TB is transmitted and received, including the virtual direction, can be double the actual number of first transducers 52 (12 directions in this embodiment), thereby improving the azimuth resolution.

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

[0098] The filter 14 performs a predetermined filtering process on the original received signals of each of the first oscillators 52a to 52f and the second oscillator 53. The filter 14 then stores the values ​​obtained from the filtering process in the storage means 15 as the received signals of each of the first oscillators 52a to 52f and the second oscillator 53, and also includes the virtual received signals if a virtual received signal is generated for a virtual direction. The receiving units 13a to 13g and the filter 14 constitute the received signal generation means of the present invention.

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

[0100] Now, with reference to Figure 7, the details of the received signal array 15a will be explained. Figure 7 is a schematic diagram showing the contents of the received signal array 15a. Note that Figure 7 shows the received signal array 15a when the filter 14 generates a virtual received signal in a virtual direction.

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

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

[0103] In other words, in direction θ, "1" indicates the direction of the first central axis C1b. In direction θ, "2" indicates the first virtual direction (referred to as "Virtual 1" in Figure 7) set at an intermediate position between the first central axis C1b and the first central axis C1a. In direction θ, "3" indicates the direction of the first central axis C1a. In direction θ, "4" indicates the second virtual direction set at an intermediate position between the first central axis C1a and the first central axis C1f. In direction θ, "5" indicates the direction of the first central axis C1f. In direction θ, "6" indicates the third virtual direction set at an intermediate position between the first central axis C1f and the first central axis C1e.

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

[0105] Furthermore, the direction θ is assigned the value "13" relative to the second central axis C2, which is the vertical direction. In other words, in direction θ, "13" indicates the direction of the second central axis C2.

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

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

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

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

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

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

[0112] Returning to Figure 6, the explanation continues. The seabed depth determination means 16 determines the depth of the seabed SB located directly beneath (vertically) the ship 71. The determination of the seabed SB depth is made by utilizing the fact that when the transducer receives reflected ultrasonic TB waves from the seabed SB, the level of the signal (voltage) output from the transducer is much higher and the rise slope is also larger than when it receives reflected ultrasonic TB waves from other objects. That is, when the level indicated by the received signal is above a predetermined level threshold and / or the amount of change in the level indicated by the received signal is above a predetermined change threshold, the seabed depth determination means 16 determines that the received signal is due to the reception of reflected waves from the seabed SB, and identifies the depth specified by the time the determination was made as the vertical depth directly beneath the ship 71.

[0113] The seabed depth determination means 16 is performed based on the intensity of the reflected waves of the ultrasonic TB transmitted and received by the second transducer 53, which is stored in the received signal array 15a. As described above, the second transducer 53 has its second central axis C2 located in the vertical direction directly below the ship 71, so it can accurately determine the depth of the seabed SB in the vertical direction directly below the ship 71.

[0114] However, since 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 ultrasonic waves TB from the seabed SB in the vertical direction directly below the ship 71. Therefore, although the accuracy will be lower than when the second transducer 53 is used, the seabed depth determination means 16 may determine the depth of the seabed 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 seabed SB determined by the seabed depth determination means 16 is used when the detection result image generation means 17 generates the horizontal detection result image 22 shown in Figure 5.

[0116] The detection result image generation means 17 generates a detection result image to be displayed on the display device 21 based on the received signals for each of the first central axes C1a to C1f and the first to sixth virtual directions generated by the receiving units 13a to 13g and the filter 14, 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 generation means 17 generates at least the horizontal detection result image 22 shown in Figure 5.

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

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

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

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

[0121] Furthermore, the level of the received signal at the coordinate (R, θ) = (19.2, 12.7) is calculated by taking a weighted average of the levels of the received signals of the elements of the received signal array 15a, which are indicated by the respective indices (R, θ) = (19, 12), (19, 1), (20, 12), and (20, 1). The reason why the index "1" is used for direction θ is that the direction next to the direction indicated by direction θ "12" is the direction indicated by direction θ "1" in a clockwise direction.

[0122] The detection result image generation means 17 generates a horizontal detection result image 22 by identifying the intensity of the reflected wave from the underwater position corresponding to each pixel and assigning a color corresponding to the intensity of the reflected wave. The detection result image generation 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 applied to reflected waves from a position shallower than the depth of the seabed SB. The second palette 17b is applied to reflected waves from a position deeper than the depth of the seabed SB, and is a palette defined by a different color than that 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] In the ultrasonic sonar device 1 according to this embodiment, when the detection result image generation means 17 generates a horizontal detection result image 22, it first assigns a color using the first palette 17a to the intensity of reflected waves from all pixels, i.e., all positions included in a predetermined range. Then, the detection result image generation means 17 reassigns a color to the horizontal detection result image 22 to which the first palette 17a has been assigned, using the second palette 17b, according to the intensity of reflected waves from the underwater position corresponding to the pixel, for pixels corresponding to positions deeper than the depth of the seabed SB determined by the seabed depth determination means 16, and overwrites the image with the reassigned color.

[0125] As a result, in the horizontal detection result image 22, the ultrasonic sonar device 1 assigns a color defined in the first palette 17a to the reaction 22a of the detected object GF, and a color defined in the second palette 17b to the reaction 22b of the seabed SB. The colors defined in the first palette 17a and the colors defined in the second palette 17b are different as described above. Therefore, in the horizontal detection result image 22, the color assigned to the reaction 22a of the detected object GF and the color assigned to the reaction 22b of the seabed SB can be clearly distinguished. Consequently, the user can easily distinguish the detected object GF and / or the seabed SB from the horizontal detection result image 22.

[0126] Here, Figure 8 is a schematic diagram illustrating an example of a first pallet 17a and a second pallet 17b. In the example shown in Figure 8, the first pallet 17a and the second pallet 17b are stored in a memory area with contiguous addresses. In Figure 8, the relative address ("Address" in Figure 8) within the memory area where the first pallet 17a and the second pallet 17b are stored is represented by 8 bits (0 to 255). The first pallet 17a is defined at a relative address where the most significant bit (MSB) is "0" (relative address 0 to 127), and the second pallet 17b is defined at a relative address where the most significant bit (MSB) is "1" (relative address 128 to 255). That is, the most significant bit of the relative address functions as an identification bit to distinguish between the first pallet 17a and the second pallet 17b.

[0127] Furthermore, in both the first palette 17a and the second palette 17b, the lower seven bits of the relative address correspond to the intensity of the reflected wave. The color assigned to each relative address, i.e., the intensity of the reflected wave, is defined by the intensity of each of the RGBA colors, i.e., "red," "green," and "blue," and the "transparency." As described above, the colors defined in the first palette 17a and the colors defined in the second palette 17b are defined to be different.

[0128] In this embodiment, the intensity of the reflected wave is represented by 7 bits. When the detection result image generation means 17 identifies the color of each pixel using the first palette 17a, it identifies the color to be assigned to the intensity of the reflected wave from the underwater position corresponding to that pixel, identified by the above method, using a relative address represented by adding a "0" to the most significant bit. When the detection result image generation means 17 identifies the color of each pixel using the second palette 17b, it identifies the color to be assigned to the intensity of the reflected wave from the underwater position corresponding to that pixel, identified by the above method, using a relative address represented by adding a "1" to the most significant bit. As a result, by simply switching the most significant bit of the relative address between "0" and "1", the palette used to assign a color to the intensity of the reflected wave can be easily switched between the first palette 17a and the second palette 17b.

[0129] Furthermore, the second palette 17b may be defined for relative addresses where the most significant bit (MSB) is "0" (relative address 0 to 127), and the first palette 17a may be defined for relative addresses where the most significant bit (MSB) is "1" (relative address 128 to 255). In this case, when the detection result image generation means 17 identifies the color of each pixel using the first palette 17a, it identifies the color to be assigned to the intensity of the reflected wave from the underwater position corresponding to that pixel, identified by the above method, from the relative address represented by adding "1" to the higher bits. Also, when identifying the color of each pixel using the second palette 17b, it identifies the color to be assigned to the intensity of the reflected wave from the underwater position corresponding to that pixel, identified by the above method, from the relative address represented by adding "0" to the higher bits.

[0130] Furthermore, although the example shown in Figure 8 illustrates the case where the first pallet 17a and the second pallet 17b are stored in memory areas with contiguous addresses, the first pallet 17a and the second pallet 17b may be stored in separate memory areas.

[0131] Furthermore, although this embodiment describes the case where the intensity of the reflected wave is represented by 7 bits, when the intensity of the reflected wave is represented by M bits, the relative addresses of the first palette 17a and the second palette 17b, excluding the most significant bit (identification bit), are 0 to (2 Ｍ Alternatively, a color may be assigned to the intensity of each reflected wave, such that (-1) is true. This allows for a detailed color representation of the intensity of all reflected waves.

[0132] On the other hand, when the intensity of the reflected wave is represented by M bits, the relative addresses of the first palette 17a and the second palette 17b, excluding the most significant bit (identification bit), are 0 to (2 Ｎ-1) Colors may be assigned to the intensity of the reflected wave such that (where M > N). In this case, the upper N bits of the intensity of the reflected wave, which is represented 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 that can be assigned to the intensity of the reflected wave, but it also reduces the memory capacity required for the first palette 17a and the second palette 17b.

[0133] Furthermore, while the example in Figure 8 describes a case where the color assigned to the intensity of the reflected wave is defined by the intensity of each color, "red," "green," and "blue," and "transparency," any known method of defining color is acceptable. For example, RGB, i.e., transparency, may be omitted and the color may be defined only by the intensity of each color, "red," "green," and "blue." Alternatively, CMYK, i.e., the color may be defined by the intensity of each color, cyan, magenta, yellow, and black, or YCbCr, i.e., luminance Y and two color differences Cb and Cr. In addition, HSL, i.e., hue H, saturation S, and luminance L, or HSV, i.e., hue H, saturation S, and lightness V, may be used.

[0134] Furthermore, the detection result image generation means 17 may provide multiple first palettes 17a, allowing the user to select one of the multiple first palettes 17a to be assigned a color according to the intensity of the reflected waves from the object GF by operating the operation button 31. Alternatively, the detection result image generation means 17 may provide multiple second palettes 17b, allowing the user to select one of the multiple second palettes 17b to be assigned a color according to the intensity of the reflected waves from the seabed SB by operating the operation button 31. This allows the user to display the reaction 22a of the object GF and the reaction 22b of the seabed SB in the horizontal detection result image 22 in their preferred color.

[0135] Furthermore, multiple combinations of the first palette 17a and the second palette 17b may be provided, allowing the user to select one of these combinations by operating the operation button 31. For example, combinations of the first palette 17a and the second palette 17b with different brightness levels, combinations of the first palette 17a and the second palette 17b with different saturation levels, combinations of the first palette 17a and the second palette 17b with different transparency (transmittance) levels, and combinations of the first palette 17a and the second palette 17b with different hues may be provided, allowing the user to select how the color assigned according to the intensity of the reflected waves from the target object GF and the color assigned according to the intensity of the reflected waves from the seabed SB differ from each other, using brightness, saturation, transparency (transmittance), and hue. This allows the user to select how the color assigned according to the intensity of the reflected waves from the target object GF and the color assigned according to the intensity of the reflected waves from the seabed SB differ according to their preference.

[0136] Furthermore, the range to which the first palette 17a and the second palette 17b are applied may be switched based on settings 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 seabed SB, and the second palette 17b is applied to reflected waves from positions shallower than the depth of the seabed SB. Then, when the user operates the operation button 31 again, the application range may be returned to so that the first palette 17a is applied to reflected waves from positions shallower than the depth of the seabed SB, and the second palette 17b is applied to reflected waves from positions deeper than the depth of the seabed SB. This makes it possible for the user to select whether the color assigned according to the intensity of reflected waves from the object GF is brighter in brightness, more saturated, or less transparent (transmitted). Therefore, the user can display the reaction 22a of the detected object GF and the reaction 22b of the seabed SB in the horizontal detection result image 22 in a way that is different to their preference.

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

[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 explained, mainly with reference to Figures 1, 2, and 6.

[0139] When the user turns on the power to the ultrasonic sonar device 1 via the operation button 31, or when the user is instructed to start horizontal detection using the sonar function while the power is on, the ultrasonic sonar device 1 first drives the lifting device 41 to bring the transmitting and receiving unit 50 out of the water from the bottom of the ship 71. In the case of an ultrasonic sonar device 1 that does not have a lifting device 41 and in which the transmitting and receiving unit 50 is fixed to the ship 71 in a position where ultrasonic TB can be sent and received toward the water, the operation of driving the lifting device 41 is omitted.

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

[0141] The ultrasonic TB transmitted from the first transducers 52a to 52f and the second transducer 53 is reflected from the detection target object GF, seabed SB, etc., that are present in a predetermined range from which the ultrasonic TB is transmitted. The reflected waves are received by the first transducers 52a to 52f and the second transducer 53, and signals (voltages) are output from the first transducers 52a to 52f and the second transducer 53 as the intensity of the reflected waves received in each direction of the first central axis C1a to C1f and the second central axis C2, respectively.

[0142] The signals (voltages) output from the first transducers 52a to 52f and the second transducer 53 are amplified by corresponding receiving units 13a to 13g at predetermined time intervals after the transmission of the ultrasonic TB, then sampled by converting them into 7-bit digital signals (digital values), and output as received signals (original received signals) in each direction of the first central axis C1a to C1f and the second central axis C2.

[0143] These original received signals are subjected to spatial (and temporal) filtering by filter 14. Furthermore, filter 14 may set first to sixth virtual directions at intermediate positions between adjacent first central axes C1a to C1f, and receive signals assuming that ultrasonic TBs are virtually transmitted and received in each of these first to sixth virtual directions may be generated from the received signals of the first transducers 52a to 52f.

[0144] The levels of the received signals in each direction of the first central axis C1a to C1f and the second central axis C2, after filtering by the filter 14, are stored in each element of the received signal array 15a by the storage means 15. If the levels of the virtual received signals in the first virtual direction to the sixth virtual direction, which are virtually set, are also output, these virtual received signal levels are also stored in each element of the received signal array 15a as shown in Figure 7.

[0145] Next, the level of the received signal in the direction of the second central axis C2 (vertical direction) stored in the received signal array 15a is referenced by the seabed depth determination means 16 to determine the depth of the seabed SB in the vertical direction directly beneath the vessel 71. Furthermore, based on the level of the received signal in the direction of the first central axis C1a to C1f (directions set in the azimuth direction) stored in the received signal array 15a, the detection result image generation means 17 generates one or more detection result images, including the horizontal detection result image 22, to be displayed on the display device 21. 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 user the latest detection results by repeatedly performing the transmission of ultrasonic TB and the reception of reflected ultrasonic TB waves, as well as generating and displaying detection result images based on the received signals.

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

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

[0149] Next, the detection result image generation means 17 sets a first palette 17a as a palette that defines the colors to be assigned to the intensity of the reflected wave identified at each pixel (S2). 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".

[0150] Then, the detection result image generation 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) based on the intensity of the reflected wave from the underwater position corresponding to that pixel using the first palette 17a (S3).

[0151] Next, the detection result image generation means 17 sets a second palette 17b as a palette that defines the colors to be assigned to the intensity of the reflected waves (S4). 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".

[0152] Furthermore, the detection result image generation means 17 obtains information on the depth of the seabed SB in the vertical direction directly beneath the vessel 71 from the seabed depth determination means 16 (S5). The detection result image generation means 17 identifies the coordinates of the region deeper than the seabed SB depth in the horizontal detection result image 22 from the seabed SB depth information obtained in the processing of S5 (S6).

[0153] Then, the detection result image generation means 17, for the pixels in the horizontal detection result image 22 identified in processing S6 that are deeper than the depth of the seabed SB, reassigns a color in the second palette 17b to the intensity of the reflected wave from the underwater position corresponding to that pixel, and fills (overwrites) the pixels with the reassigned color (S7). Then, the detection result image generation means 17 terminates the horizontal detection result image generation process.

[0154] As a result, the detection result image generation means 17 generates the horizontal detection result image 22 shown in Figure 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 the reaction 22a of the detected object GF, and a color defined in the second palette 17b to the reaction 22b of the seabed SB. The colors defined in the first palette 17a and the colors defined in the second palette 17b are different as described above. Therefore, in the horizontal detection result image 22, the color assigned to the reaction 22a of the detected object GF and the color assigned to the reaction 22b of the seabed SB can be clearly distinguished. Accordingly, the user can easily distinguish the detected object GF and / or the seabed SB from the horizontal detection result image 22.

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

[0156] (1) The transmitting / receiving unit 50 transmits ultrasonic TB into the water over a predetermined range, and the reflected waves of the ultrasonic TB reflected from each position in the water are received for each predetermined direction set in the azimuth direction (each direction of the first central axis C1a to C1f and the second central axis C2). Based on the reflected waves received by the transmitting / receiving unit 50, a received signal is generated by the receiving units 13a to 13g and the filter 14 for each direction of the first central axis C1a to C1f and the second central axis C2. Based on the received signals for each direction of the first central axis C1a to C1f and the second central axis C2 generated by the receiving units 13a to 13g and the filter 14, the detection result image generation 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 each position over the predetermined range. From this horizontal detection result image 22, the user can determine whether or not there is a detected object GF, as well as the direction and horizontal distance of the detected object GF.

[0157] (2) Based on the intensity of the reflected waves received by the transmitting / receiving unit 50, the depth of the seabed SB is determined by the seabed depth determination means 16. The detection result image generation means 17 then 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 seabed SB and to positions within a predetermined range that are deeper than the depth of the seabed SB. As a result, the user can easily determine from the colors represented in the horizontal detection result image 22 whether the reaction displayed in the horizontal detection result image 22 is the reaction 22a of the object to be detected GF or the reaction 22b of the seabed SB. Thus, the user can easily distinguish between the object to be detected GF and / or the seabed SB.

[0158] (3) The detection result image generation means 17 first generates a provisional horizontal detection result image 22 covering the entire detection range, which is a predetermined range, using the color (first palette 17a) assigned to positions shallower than the depth of the seabed SB (S3 in Figure 9). Subsequently, the detection result image generation means 17 overwrites the pixels at positions deeper than the depth of the seabed SB with the color assigned to the region at positions deeper than the seabed SB (S7 in Figure 9). The horizontal detection result image 22 after this overwriting is displayed on the display device 21. As a result, the generation process of the horizontal detection result image 22 can be executed with a simple program structure, so that the memory capacity required for the program is kept small, and a horizontal detection result image 22 can be generated that allows the user to easily identify the detected object GF and / or the seabed SB.

[0159] (4) Each of the multiple first transducers 52a to 52f is fixed in the transmitting and receiving unit 50 such that its first central axis C1a to C1f is in a predetermined direction, and when the transmitting and receiving unit 50 is attached to the ship 71, its first central axis C1a to C1f is at a predetermined angle ω with respect to the vertical direction (direction of the second central axis C2) (see Figures 3 and 4). Each of the first transducers 52a to 52f has predetermined directional characteristics that include at least the central axis C1 of the adjacent first transducer 52 and the vertical direction (see Figures 4(c) and (d)). As a result, with a small number of first transducers 52a to 52f, ultrasonic TB can be transmitted simultaneously over a predetermined range, and the reflected waves can be received to detect the object GF to be detected. Thus, an ultrasonic sonar device 1 capable of high-speed detection can be constructed at low cost.

[0160] Here, since the first transducers 52a to 52f also have directional characteristics in the vertical direction, they receive reflected waves from the seabed SB in the vertical direction before receiving reflected waves from the seabed SB in the direction of their own first central axis C1a to C1f. However, since the horizontal detection result image 22 is a projection of the detection results onto a plane parallel to the horizontal plane, if the same color is assigned to the reaction 22a of the detected object GF and the reaction 22b of the seabed SB, it is difficult to distinguish and grasp the reaction 22b of the vertical seabed SB. In contrast, the detection result image generation means 17 generates the horizontal detection result image 22 by assigning different colors to positions shallower than the depth of the seabed SB within a predetermined range and to positions deeper than the depth of the seabed SB within a predetermined range. Therefore, the user can easily determine the reaction 22b of the vertical seabed SB in the horizontal detection result image 22.

[0161] (5) In addition to the first transducers 52a to 52f, a second transducer 53 is provided on the transducer unit 50 when the transducer unit 50 is attached to the ship 71, with the second central axis C2 fixed in the vertical direction. This enables detection of the object GF in the vertical direction and / or measurement of the vertical depth with high accuracy.

[0162] (6) The second transducer 53, whose second central axis C2 is positioned vertically, transmits ultrasonic waves TB, and the seabed depth determination means 16 determines the depth of the seabed SB in the vertical direction of the ship 71 based on the intensity of the reflected waves received by the second transducer 53. This allows for a more accurate determination of the depth of the seabed SB in the vertical direction of the ship 71 compared to using the first transducers 52a to 52f, whose first central axes C1a to C1f are positioned at a predetermined angle ω with respect to the vertical direction. Therefore, the horizontal detection result image 22 can clearly show the user the response 22b from the depth of the seabed SB in the vertical direction 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 Figures 10 to 12. Figure 10 is a block diagram showing the electrical configuration of the ultrasonic sonar device 1 according to the second embodiment. Figure 11 is a schematic diagram showing the conversion table 17c of the detection result image generation means 17 of the ultrasonic sonar device 1 according to the second embodiment. Figure 12 is a flowchart showing the horizontal detection result image generation process executed by the detection result image generation means 17 of the ultrasonic sonar device 1 according to the second embodiment.

[0164] In the first embodiment, the ultrasonic sonar device 1 generates the horizontal detection result image 22 shown in Figure 5 by first generating a provisional horizontal detection result image 22 over the entire detection range, which is a predetermined range, using a color (first palette 17a) assigned to positions shallower than the depth of the seabed SB, and then overwriting the generated provisional horizontal detection result image 22 with the color assigned to the region deeper than the seabed SB for pixels at positions deeper than the seabed SB. In contrast, the ultrasonic sonar device 1 shown in Figure 5 generates the horizontal detection result image 22 shown in Figure 5 in a single coordinate transformation process using a transformation table 17c provided by the detection result image generation device 17.

[0165] The following description focuses on the differences between the ultrasonic sonar device 1 according to the second embodiment and the ultrasonic sonar device 1 according to the first embodiment. Components identical to those in the ultrasonic sonar device 1 according to the first embodiment are denoted by the same reference numerals, and their descriptions are omitted or simplified.

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

[0167] As shown in Figure 11, the conversion table 17c, similar to the first embodiment, associates the Cartesian coordinates (X, Y) representing each pixel of the horizontal detection result image 22 with the polar coordinate system coordinates (R, θ), which consist of information θ (direction θ) corresponding to the direction and information R (distance R) corresponding to the distance, which are indices of the received signal array 15a that correspond to those coordinates (X, Y). However, in addition to this, the conversion table 17c also associates the Cartesian coordinates (X, Y) representing each pixel with a distance R', which is the distance from the transmitting / receiving unit 50 at the underwater position corresponding to the pixel at those coordinates (X, Y), expressed with a length equal to one unit of the depth D of the seabed SB output by the seabed depth determination means 16. Here, distance R corresponds to the index of the received signal array 15a, whereas distance R' is provided for comparison with the depth D of the seabed SB.

[0168] The detection result image generation means 17 uses a conversion table 17c to identify the polar coordinate system coordinates (R, θ) corresponding to the coordinates (X, Y) of each pixel in the horizontal detection result image 22. Then, for each pixel, the detection result image generation 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 in the method described in the first embodiment, and uses the identified level of the received signal as the intensity of the reflected wave from the underwater position corresponding to that pixel. In this way, the detection result image generation means 17 can identify the intensity of the reflected wave from the underwater position corresponding to that pixel 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, from the level of the azimuthal received signal stored in the received signal array 15a. Up to this point, it is the same as in the first embodiment.

[0169] On the other hand, the detection result image generation means 17 of the ultrasonic sonar device 1 according to the second embodiment identifies the polar coordinates (R, θ) corresponding to the coordinates (X, Y) of each pixel in the horizontal detection result image 22, and at the same time identifies the distance R' from the transmitting / receiving unit 50 at the underwater position from the conversion table 17c. Then, it compares the identified distance R' with the depth D of the seabed SB obtained from the seabed depth determination means 16.

[0170] As a result, if the distance R' is less than or equal to the depth D of the seabed SB, it is determined that the pixel indicates a position shallower than the depth D of the seabed SB, and a color is assigned to that pixel using the first palette 17a based on the intensity of the reflected wave from the underwater position corresponding to that pixel, which has been identified. If the distance R' is greater than the depth D of the seabed SB, it is determined that the pixel indicates a position deeper than the depth D of the seabed SB, and a color is assigned to that pixel using the second palette 17b based on the intensity of the reflected wave from the underwater position corresponding to that pixel, which has been identified. In this way, the horizontal detection result image 22 shown in Figure 5 is generated in a single coordinate transformation process.

[0171] Next, the details of the horizontal detection result image generation process, in which the detection result image generation means 17 generates the horizontal detection result image 22 using the conversion table 17c described above, will be explained with reference to Figure 12.

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

[0173] Next, the detection result image generation means 17 uses the conversion table 17c to identify the polar coordinates (R, θ) corresponding to the orthogonal coordinates (X, Y) set as pixels for color identification, and the distance R' from the transmitting / receiving unit 50 at the underwater location corresponding to that pixel (S13). Then, the detection result image generation means 17 compares the distance R' identified in the S13 process with the depth D of the seabed SB obtained in the S11 process (S14).

[0174] As a result, if the distance R' is less than or equal to the depth D of the seabed SB (S14: No), the detection result image generation means 17 determines that the pixel indicates a position shallower than the depth D of the seabed 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 that pixel that has been identified (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 in S14 shows that the distance R' is greater than the depth D of the seabed SB (S14: Yes), the detection result image generation means 17 determines that the pixel indicates a position deeper than the depth D of the seabed SB, and sets a second palette 17b as a palette to assign a color to the intensity of the reflected wave from the underwater position corresponding to that pixel that has been identified (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 determines the intensity (7 bits) of the reflected wave at the underwater position corresponding to the orthogonal coordinates (X, Y) set as the pixel for color identification, using the polar coordinates (R, θ) identified in processing S13 and the received signal array 15a, by the method described above, and then assigns the color corresponding to the identified reflected wave intensity as the color of the pixel using the palette assigned in processing S15 or S16 (S17).

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

[0178] Next, the detection result image generation means 17 determines whether the X coordinate of the pixel whose color has been identified in the previous processing is less than "100" (S18). If the X coordinate is less than "100" (S18: Yes), it adds 1 to the X coordinate (S19) and returns to the process in S13. As a result, the Y coordinate remains unchanged, and the processes in S13 to S17 are executed for the pixel one position away 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 judgment in S18 is that the X coordinate is 100 or greater (S18: No), the detection result image generation 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). If the result is that the Y coordinate is less than 100 (S20: Yes), then 1 is added to the Y coordinate and -100 is substituted for the X coordinate (S21), and the process returns to S13. As a result, the process in S13 to S17 is executed for the pixel whose X coordinate is -100, while moving one row in the positive direction of the Y coordinate, and the color of that pixel is identified.

[0180] Furthermore, if the Y coordinate is 100 or greater as a result of the judgment in S20 (S20: No), it 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 provides the following effects in addition to the effects of the ultrasonic sonar device 1 according to the first embodiment.

[0182] (7) For each direction of the first central axis C1a to C1f and the second central axis C2, the received signals generated by the receiving units 13a to 13g and the filter 14 are stored in the received signal array 15a of the storage means 15, corresponding to 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 TB that forms the basis of the received signal was generated. Meanwhile, the detection result image generation means 17 identifies each pixel of the horizontal detection result image 22 in Cartesian coordinates (X, Y). The detection result image generation means 17 also has a conversion table 17c that associates the polar coordinates (R, θ) corresponding to the Cartesian coordinates (X, Y) of each pixel. In this conversion table 17c, the distance R' from the transmitting / receiving unit 50 at the underwater position corresponding to the pixel indicated by the Cartesian coordinates (X, Y) is also associated with the Cartesian coordinates (X, Y) of each pixel. Then, the detection result image generation means 17 determines, for each pixel of the horizontal detection result image 22, the intensity of the reflected wave from the underwater position corresponding to that pixel, based on the received signal stored in the storage means 15, which is associated with the polar coordinates (R, θ) corresponding to the orthogonal coordinates (X, Y) of the pixel, which are determined by the conversion table 17c. Furthermore, the detection result image generation means 17 determines whether the pixel is at a position shallower or deeper than the depth D of the seabed SB, based on the distance R' from the transmitting / receiving unit 50 at the underwater position corresponding to the pixel, which is determined by the conversion table 17c. Based on the result of this determination, the horizontal detection result image 22 is generated while assigning different colors to the intensity of the reflected wave from the underwater position corresponding to the determined pixel. In this way, with a single coordinate transformation process using the conversion table 17c, the horizontal detection result image 22 can be generated with different colors assigned to positions shallower than the depth D of the seabed SB within a predetermined range and to positions deeper than the depth D of the seabed SB within a predetermined range. Therefore, it is possible to generate a horizontal detection result image 22 that allows the user to easily identify the target object GF and / or the seabed SB while suppressing the time required to generate the horizontal detection result image 22.

[0183] (8) The detection result image generation means 17 has a first palette 17a which defines the colors to be assigned to the intensity of the reflected waves, and a second palette 17b which defines the colors to be assigned to the intensity of the reflected waves using colors different from those defined in the first palette 17a. The detection result image generation means 17 then assigns a color to the intensity of the reflected waves from the underwater position corresponding to the specified pixel, based on the distance R' from the transmitting / receiving unit 50 at the underwater position corresponding to the pixel, which is identified by the conversion table 17c. If the pixel is located at a position shallower than the depth D of the seabed SB, the first palette 17a is used, and if the pixel is located at a position deeper than the depth D of the seabed SB, the second palette 17b is used. As a result, with a single coordinate transformation process using the transformation table 17c, by simply changing the palette used based on the distance R' from the transmitting / receiving unit 50 at the underwater position corresponding to the pixel, 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 seabed SB and to positions within a predetermined range that are deeper than the depth D of the seabed SB. Therefore, it is possible to easily generate a horizontal detection result image 22 that allows the user to easily identify the object to be detected GF and / or the seabed SB while suppressing the time required to generate the horizontal detection result image 22.

[0184] (Modifications) The present invention has been described above based on the embodiments, but it can be easily inferred that the present invention is not limited in any way to the above embodiments, and that various improvements and modifications are possible without departing from the spirit of the present invention. For example, each embodiment may be modified by adding or replacing some or more parts of the configuration of other embodiments with parts or more parts of the configuration of other embodiments, including the modifications described below. Also, the numerical values ​​given in the above embodiments are just examples, and it is of course possible to use other numerical values.

[0185] In the embodiments described above, the case in which the first transducers 52a to 52f are inclined to face inward (towards the side where the second transducer 53 is located) was explained. However, the invention is not limited to this, and the first transducers 52a to 52f may also be inclined to face outward (towards the side opposite to the side where the second transducer 53 is located). In this case as well, it is preferable that the first central axes C1a to C1f each form a predetermined angle ω with respect to the second central axis C2 (the vertical direction when the transmitting / receiving unit 50 is attached to the ship 71), selected from a range of 20° to 50°.

[0186] In the embodiments described above, the case in which the first transducers 52a to 52f are provided around the second transducer 53 in the transmitting / receiving unit 50 has been explained. However, the arrangement of the first transducers 52a to 52f and the second transducer 53 in the transmitting / receiving unit 50 can be arbitrary, as long as, when the transmitting / receiving unit 50 is attached to the ship 71, the second central axis C2 is in the vertical direction, the first central axes C1a to C1f form a predetermined angle ω with respect to the second central axis C2 (in other words, the vertical direction), and the first central axes C1a to C1f are in a predetermined direction. For example, the first oscillators 52a to 52f and the second oscillator 53 may be arranged in one or two rows, or the first oscillators 52a to 52f may be arranged in two rows and the second oscillator 53 may be placed at any position between the two rows of the first oscillators 52a to 52f.

[0187] In the embodiments described above, a first palette 17a, which is applied to reflected waves from a position shallower than the depth of the seabed SB, and a second palette 17b, which is applied to reflected waves from a position deeper than the depth of the seabed SB and defines a different color from the color defined in the first palette 17a, were described in which a color is assigned to reflected waves from each position. In contrast, the palette itself may be a common one, which defines the color to be assigned to the intensity of the reflected wave, for example, using RGB, regardless of the position where the reflected wave is generated. The same first transparency (first transmittance) value may be set for the intensity of reflected waves from a position shallower than the depth of the seabed SB, and the same second transparency (second transmittance) value may be set for the intensity of reflected waves from a position deeper than the depth of the seabed SB (however, the first transparency (first transmittance) and the second transparency (second transmittance) may be different values). This also allows the ultrasonic sonar device 1 to generate a horizontal detection result image 22 by assigning different colors to positions within a predetermined range that are shallower than the depth of the seabed SB and to positions within a predetermined range that are deeper than the depth of the seabed SB.

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

[0189] In each of the embodiments described above, the case was explained in which the color assigned to positions shallower than the depth of the seabed SB within a predetermined range and the color assigned to positions deeper than the depth of the seabed SB within a predetermined range are always different in the horizontal detection result image 22. However, the system may also include a display mode in which the color assigned to positions shallower than the depth of the seabed SB within a predetermined range and the color assigned to positions deeper than the depth of the seabed SB within a predetermined range are the same, and the user can switch between these display modes by operating the operation button 31.

[0190] In the embodiments described above, the number of first transducers 52 in the transmitting / receiving unit 50 is reduced, and the ultrasonic TB is transmitted and received simultaneously from the first transducers 52 over a predetermined range set in all directions of the ship 71 to perform horizontal detection. However, the present invention, in which the detection result image generation means 17 generates a horizontal detection result image 22 by assigning different colors to positions within the predetermined detection range that are shallower than the depth of the seabed SB and to positions within the predetermined range that are deeper than the depth of the seabed SB, is also applicable to detection using PPI sonar and scanning sonar.

[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 Filter 15 Storage means 15a Received signal array 16 Seabed depth determination means 17 Detection result image generation means 17a First pallet 17b Second pallet 17c Conversion table 22 Horizontal detection result image 50 Transmitting and receiving unit 52 First transducer 52a First transducer 52b First transducer 52c First transducer 52d First transducer 52e First transducer 52f First transducer 53 Second transducer 71 Ship 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 Bottom depth E1a Directional characteristics E1b Directional characteristics E1d Directional characteristics E1f Directional characteristics GF Detection target SB Bottom TB Ultrasonic wave ω Angle

Claims

1. An ultrasonic sonar device comprising: a transmitting / receiving unit configured to transmit ultrasonic waves over a predetermined range in water and to receive reflected ultrasonic waves reflected from each position in the water for each predetermined direction including at least a plurality of directions set in the azimuthal direction; a receiving signal generation means that generates a received signal for each predetermined direction based on the reflected waves received by the transmitting / receiving unit; a detection result image generation means that generates 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 predetermined direction generated by the receiving signal generation means; and a seabed depth determination means that determines the depth of the seabed based on the intensity of the reflected waves received by the transmitting / receiving unit, wherein the detection result image generation means generates the detection result image by assigning different colors to positions within the predetermined range that are shallower than the depth of the seabed and to positions within the predetermined range that are deeper than the depth of the seabed.

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

3. The ultrasonic sonar device according to claim 1, characterized in that the detection result image generation means first generates the detection result image over a predetermined range using a color assigned to a position shallower than the depth of the seabed, and then overwrites the pixels at positions deeper than the depth of the seabed with the color assigned to a position deeper than the depth of the seabed, and displays the detection result image after overwriting.

4. The ultrasonic sonar device according to claim 1, comprising: a storage means for storing the received signals generated by the receiving signal generation means for each predetermined direction, associated with polar coordinates indicated by information corresponding to that direction and information corresponding to the distance to the location where the reflected ultrasonic waves that form the basis of the received signals originated; the detection result image generation means for identifying each pixel of the detection result image in orthogonal coordinates; a conversion table that associates the orthogonal coordinates of each pixel with the corresponding polar coordinates and the distance from the transmitting / receiving unit at the underwater location corresponding to that pixel; for each pixel of the detection result image, the intensity of the reflected waves from the underwater location corresponding to that pixel is identified based on the received signals stored in the storage means, associated with the polar coordinates corresponding to the orthogonal coordinates of the pixel identified by the conversion table; and a determination is made as to whether the pixel is at a shallower or deeper location than the depth of the seabed based on the distance from the transmitting / receiving unit at the underwater location 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 waves from the underwater location corresponding to the identified pixel based on the result of the determination.

5. The ultrasonic sonar device according to claim 4, wherein the detection result image generation 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, based on the distance from the transmitting / receiving unit at the underwater position corresponding to the pixel, which is identified by the conversion table, the first palette is used if the pixel is at a position shallower than the depth of the seabed, and the second palette is used if the pixel is at a position deeper than the depth of the seabed, thereby assigning a color to the intensity of reflected waves from the underwater position corresponding to the identified pixel.

6. The ultrasonic sonar device according to claim 1, wherein the transmitting and receiving unit comprises a plurality of first transducers having predetermined directional characteristics, and each of the plurality of first transducers is fixed such that its central axis is in the predetermined direction and, when the transmitting and receiving unit is attached to a ship, its central axis is positioned at a predetermined angle with respect to the vertical direction, and has predetermined directional characteristics that include at least the central axis of an adjacent first transducer and the vertical direction.

7. The ultrasonic sonar device according to claim 6, wherein the transmitting and receiving unit further comprises a second transducer fixed such that its central axis is positioned vertically when attached to a ship.

8. The ultrasonic sonar device according to claim 7, characterized in that the seabed depth determination means determines the vertical depth of the seabed based on the intensity of the reflected waves transmitted by the second transducer and received by the second transducer.

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