JP5144005B2 - Underwater detector - Google Patents

Description

The present invention relates to an underwater detection apparatus that measures and displays an image by measuring the direction and distance of a shallow water or an underwater obstacle that hinders the navigation of a watercraft using ultrasonic wave transmission and its echo.

There is an underwater detection device as a method of knowing information such as the direction, distance, depth, etc. of shallow waters, dark reefs, floating objects, underwater obstacles, seabeds, etc. that hinder the navigation of surface navigation vessels (for example, Patent Documents 1 and 2). . This underwater detector measures the distance and depth to an obstacle by measuring the echo return time from the transmission of the ultrasonic signal to the reception of the reflected wave using a transducer that transmits and receives the ultrasonic signal. ing. In order to make the measurement result measured in this way intuitive to the user, a cross-sectional echo for the ship's longitudinal direction is displayed on the display screen, and the relationship between the position of the obstacle present in the water and the ship's position Was displayed.
US Pat. No. 5,530,680 US Pat. No. 5,675,552

However, the distance and depth to the obstacle are calculated using signals transmitted and received by the vibrator. Therefore, the calculated distance / depth information to the obstacle is actually the distance from the vibrator attached to the bottom of the ship, and as a result, the vibrator and obstacle attached to the bottom of the ship are displayed on the display screen. Will be displayed.

FIG. 14 is an explanatory diagram for explaining the positional relationship between the ship and the obstacle, where L is the distance between the vibrator and the obstacle, La is the distance between the bow and the obstacle that may cause a collision, D represents the distance between the vibrator and the seabed, and Da represents the distance between the bottom of the ship where there is a possibility of collision and the obstacle.

As shown in FIG. 14, the underwater portion of the ship that actually causes collision / grounding exists in front of or below the vibrator. However, since the positional relationship between the vibrator and the obstacle is displayed on the display screen as described above, it is very difficult to grasp the distance between the ship position and the obstacle that may actually collide. There was a problem. In particular, in sailing yachts with keels protruding in the seabed direction, the difference between the target position appearing on the display screen and the actual keel deepest part is as large as 1 to 2 m, and the information displayed on the display screen is It could not be said to accurately represent the positional relationship between the position and the obstacle. The same applies to the bow direction, and the distance from the transducer position to the bow may be 10 m or more, and it is very difficult to grasp the distance between the ship position where there is a possibility of actual collision and the obstacle.

In the conventional display method, as shown in FIG. 15, the image of the target approaching the ship is usually rewritten at every reception timing of the pulse wave transmitted and received at regular intervals. As a result, the distance between the target appearing on the display screen and the own ship approaches each time the data is rewritten, and is visually recognized by the user.

However, such a display method has a problem that it is difficult to understand a change in distance from the ship to the target over time, and the user needs to continuously view the display screen to know this. Was.

In addition, the conventional underwater detection apparatus has a problem that it is difficult to grasp the horizontal position of the target because the search range is always limited to the front cross section of the ship.

The present invention has been made in view of the above problems, and provides an underwater screen display device capable of accurately grasping the positional relationship between a ship position and an obstacle with a possibility of collision and the search range thereof. For the purpose.

In order to solve the above problems, the present invention provides a transmission / reception unit that transmits and receives an ultrasonic signal, and a cross-sectional echo in the front-rear direction of the ship based on the reception signal received by the transmission / reception unit. Acquired by a cross-section echo drawing unit that generates a signal for drawing, a distance information acquisition unit that acquires a distance between an installation position of the transmission / reception unit on the ship and a specific part of the ship, and the distance information acquisition unit Based on the measured distance information, the ship's own ship specific part display unit is displayed on the cross-sectional echo screen to display a mark indicating the difference between the installation position of the transmission / reception unit and the ship's specific part. The distance between own ship position and obstacle position can be easily grasped.

The present invention further includes an accumulation unit that accumulates past sectional echo signals, and the display unit includes a current sectional echo signal generated by the sectional echo drawing unit and at least one past sectional echo signal. By overlapping and displaying, it is possible to easily grasp the change in distance from the ship to the target over time.

According to the present invention, the distance information acquisition unit acquires the distance between the installation position of the transmission / reception unit and the specific part of the own ship, and specifies the own ship on the cross-sectional echo screen based on the acquired distance information. By displaying the part, it is possible to accurately grasp the distance between the underwater part of the ship that actually causes collision and grounding and the position of the obstacle, and shallow water and underwater obstacles that hinder the navigation of surface-going ships There is an effect that the positional relationship with the object can be accurately known.

(Embodiment 1)
Hereinafter, an underwater detection device according to Embodiment 1 of the present invention will be described with reference to the drawings.
The underwater detection device according to the first embodiment of the present invention displays a specific portion of the underwater part of the own ship that is highly likely to cause collision / grounding on the display screen of the cross-sectional echo so that the collision / grounding can be performed. It is intended to be able to accurately grasp the distance to the target obstacle.

FIG. 1 is a block diagram for explaining the configuration of an underwater detection device according to Embodiment 1 of the present invention.
In FIG. 1, the underwater detection device according to Embodiment 1 of the present invention includes a transmission / reception unit 1, a cross-sectional echo drawing unit 2, a distance information acquisition unit 3, a ship specific part drawing unit 4, and a display unit 5. Consists of.

The transmission / reception unit 1 is fixed to the bottom of the ship and transmits / receives an ultrasonic signal, transmits an electric pulse to the vibrator to form a desired transmission beam, and receives the electric wave received by the vibrator. The signal is amplified to form the desired received beam. In addition, this transmission / reception part 1 is comprised by the vibrator | oscillator array comprised by arranging a some vibrator | oscillator element in linear form, for example.

The cross-sectional echo drawing unit 2 generates a signal for drawing a cross-sectional echo screen according to the azimuth / distance / intensity of the received signal based on the received signal received by the transmitting / receiving unit 1.

The distance information acquisition unit 3 acquires distance information between the specific part of the ship and the position of the transmission / reception unit installed on the ship. The distance information acquired by the distance information acquisition unit 3 is set by the user, but may be stored in a memory in advance or may be set from the outside every time. The specific part of the ship means the underwater part of the ship that may cause a collision or grounding, and is a position set in advance by a user or the like. Examples of the specific part of the ship include the deepest part of the ship, the underwater position around the front end or the rear end of the ship. Of course, this specific part is not restricted to one place, and may be a plurality of places.

The own ship specific part drawing unit 4 causes the user to visually recognize the specific part of the own ship on the display screen based on the distance information between the specific part of the own ship acquired by the distance information acquiring unit 3 and the installation position of the transmission / reception unit. Markers such as markers and distance scales are generated.

The display unit 5 superimposes and displays the mark line generated by the ship specific part drawing unit 4 on the cross-sectional echo in the front-rear direction of the ship generated by the cross-sectional echo drawing unit 2. That is, the display unit 5 adjusts the size of the mark line, the display position, etc. according to the display scale of the cross-sectional echo display screen, and superimposes the adjusted mark line on the cross-sectional echo screen. Thereafter, the generated superimposed screen is displayed on a display device such as an LCD.

2-4 is a figure which shows an example of the display image displayed with the underwater detection apparatus by Embodiment 1 of this invention. Here, the contact position between the deepest part of the ship and the sea surface in the bow direction of the ship is defined as a specific part of the ship.

FIG. 2 is a diagram in which the distance between the installation position of the transmission / reception unit 1 and the specific part is displayed with the installation position of the transmission / reception unit 1 as the origin. As shown in FIG. 2, the ship bottom position marker displays the distance between the installation position of the transmission / reception unit 1 and the deepest part of the ship with the installation position of the transmission / reception unit 1 as the origin. Further, the bow position marker displays the distance between the installation position of the transmission / reception unit 1 and a specific part in the bow direction of the ship with the installation position of the transmission / reception unit 1 as the origin. With such a display, the user can clearly grasp the positional relationship between a specific part of the ship that may collide or be stranded and the target.

Moreover, FIG. 3 is the figure which displayed the relationship between the specific site | part of own ship and a target using the horizontal line. As shown in FIG. 3, the ship bottom position marker is a horizontal line extending from the ship bottom position of the ship in the horizontal direction with respect to the sea surface, and displays the positional relationship between the deepest part of the ship and the target. The bow position marker is a horizontal line extending from a specific part in the bow direction of the ship in a direction perpendicular to the sea surface, and displays the positional relationship between the specific part in the bow direction of the ship and the target. Such a display makes it possible to clearly grasp the positional relationship with the target position where collision / grounding is possible.

FIG. 4 shows the positional relationship between the specific part of the ship and the target using a marked line with a scale, and a distance scale is added to the display form shown in FIG. As a result, it is possible to more clearly grasp the distance relationship with a target that may collide or be stranded, and it is possible to clearly grasp the positional relationship between a specific part of the ship and the target.

As described above, according to the underwater detection device according to Embodiment 1 of the present invention, the distance information acquisition unit 3 that acquires the distance information between the installation position of the transmission / reception unit and the specific part of the ship is provided. Based on the distance information acquired by the acquisition unit 3, it is possible to clearly grasp the positional relationship between the specific part of the ship and the target by displaying the specific part of the ship on the cross-sectional echo screen. Become.

2 to 4, the display of the bottom position marker and the bow position marker has been described as an example of the display example. However, the display is not limited to this. For example, a stern position marker is displayed in addition to the bow position marker. Alternatively, when the wave transmitting / receiving unit 1 is installed at the deepest part of the ship bottom, the ship bottom position marker may not be displayed.
In addition, in the underwater detection device according to the first embodiment of the present invention, the description has been given of displaying the specific part of the own ship using the mark line, but the information drawn by the own ship specific part drawing unit 4 is the own ship's Any information may be used as long as the specific position can be visually recognized on the display screen. For example, the specific position of the ship may be displayed using a mark such as a dot.

(Embodiment 2)
Hereinafter, an underwater detection device according to Embodiment 2 of the present invention will be described with reference to the drawings.

When a specific part ahead or behind the wave receiving / receiving unit 1 is set as a specific part of the own ship having a high possibility of collision / grounding, the underwater part of the own ship that actually causes the collision / grounding is the own ship It changes according to the amount of draft. Therefore, in the underwater detection device according to the second embodiment of the present invention, the specific part of the own ship displayed on the display screen is corrected according to the draft amount of the own ship.

FIG. 5 is a block diagram for explaining the configuration of the underwater detection device according to the second embodiment of the present invention.
In FIG. 5, the underwater detection device according to the second embodiment of the present invention includes a transmission / reception unit 1, a cross-sectional echo drawing unit 2, a distance information acquisition unit 3, a ship specific part drawing unit 4, and a display unit 5. The distance information correction unit 11. In addition, the same code | symbol is attached | subjected about the component similar to the underwater detection apparatus by the said Embodiment 1, and description is abbreviate | omitted here.

The distance information correction | amendment part 11 acquires draft information, and correct | amends the distance information acquired in the distance information acquisition part 3 according to the draft amount of the own ship. In addition, the draft information input to the distance information correction unit 11 receives the ship's loading amount in addition to the actual draft amount as an input, and based on the loading amount, the ship information in the distance information correction unit 11 The draft amount may be calculated.

As described above, according to the underwater detection device according to the second embodiment of the present invention, when a specific part ahead or behind the wave transmitting / receiving unit 1 is set as the specific part of the ship, the position of the wave transmitting / receiving part 1 By providing the distance information correction unit 11 that changes the distance between specific parts of the ship according to the draft, the underwater part in front of or behind the ship with high possibility of collision / grounding is more accurately displayed on the display screen. It is possible to clearly display the positional relationship between the specific part of the ship and the target.

(Embodiment 3)
Hereinafter, an underwater detection device according to Embodiment 3 of the present invention will be described with reference to the drawings.
The underwater detection device according to the third embodiment of the present invention displays changes over time in the distance relationship between the ship and the target on the display screen.

FIG. 6 is a block diagram for explaining the configuration of the underwater detection device according to the third embodiment of the present invention.
6, the underwater detection device according to Embodiment 3 of the present invention includes a transmission / reception unit 1, a cross-sectional echo drawing unit 2, a distance information acquisition unit 3, a ship specific part drawing unit 4, and a display unit 5. And the storage unit 21. In addition, the same code | symbol is attached | subjected about the component similar to the underwater detection apparatus by the said Embodiment 1, and description is abbreviate | omitted here.

The accumulating unit 21 is an accumulating unit that stores and holds past sectional echo signals generated by the sectional echo drawing unit 2, and outputs past sectional echo signals to the display unit 5 in response to a request from the display unit 5.

Thereby, the display unit 5 can display the current cross-sectional echo signal newly generated by the cross-sectional echo drawing unit 2 and the past cross-sectional echo signal read from the storage unit 21 in an overlapping manner.

FIG. 7 is a diagram showing an example of a display image displayed by the underwater detection device according to Embodiment 3 of the present invention.

In FIG. 7, the past video read from the storage unit 21 is drawn with the hue and saturation sequentially changed for each number of transmissions so that the change at each transmission can be seen. By performing such display, a change in the positional relationship between the ship and the target can be easily visually confirmed on the display screen every time an ultrasonic signal is transmitted from the transmission / reception unit 1.

As described above, according to the underwater detection device according to the third embodiment of the present invention, the storage unit 21 that stores the past cross-sectional echo signals generated by the cross-sectional echo drawing unit 2 is provided, and the display unit 5 uses the so-called echo trail. By performing the display, it is possible for the user to easily see the change over time in the distance relationship between the ship and the target, and the user can instantly detect the risk of collision and grounding. It becomes possible.

(Embodiment 4)
Hereinafter, an underwater detection device according to Embodiment 4 of the present invention will be described with reference to the drawings.
The underwater detection apparatus according to Embodiment 4 of the present invention displays the detection range of the front cross section of the ship in a horizontal coordinate system so that the area already detected around the ship can be easily grasped. .

FIG. 8 is a block diagram for explaining the configuration of the underwater detection device according to the fourth embodiment of the present invention.
In FIG. 8, the underwater detection device according to the fourth embodiment of the present invention includes a transmission / reception unit 1, a cross-sectional echo drawing unit 2, a position / orientation information acquisition unit 31, a selection region drawing unit 32, and a selection unit 33. The horizontal position drawing unit 34, the storage unit 35, and the display unit 36. In addition, the same code | symbol is attached | subjected about the component similar to the underwater detection apparatus by the said Embodiment 1, and description is abbreviate | omitted here.

The position / orientation information acquisition unit 31 acquires the position information and direction information of the ship from the outside. For example, the position / orientation information acquisition unit 31 can acquire such information from an external navigation device or a compass.

The selection area drawing unit 32 generates a marker signal for selecting an echo for performing horizontal position display from the cross-sectional echo screen, and allows the selection unit 33 to select a target to be displayed on the horizontal coordinate system. Generate a selection area marker.

The selection unit 33 specifies the region selected by the user based on the selection region drawn on the display screen by the selection region drawing unit 32, and outputs the selected region to the horizontal position drawing unit 34.

FIG. 9 is an explanatory diagram for explaining an example of the selection region marker drawn on the cross-sectional echo screen by the selection region drawing unit of the underwater detection device according to the fourth embodiment of the present invention. FIG. 9A is an example of a selection area display method according to the angle from the ship, FIG. 9B is an example of a selection area display method according to the water depth from the ship, and FIG. An example of a display method of a rectangular selection area corresponding to the distance from the ship and the water depth is shown.

The selection area drawing unit 32 displays the selection area set using information such as the angle from the ship, water depth, distance, etc. on the cross-sectional echo screen as shown in FIG. 9, and the selection unit 33 displays the selection result. Output to the horizontal position drawing unit 34.

The selection area drawing unit 32 and the selection unit 33 are not necessarily required when displaying the target position in the horizontal coordinate system. Normally, when all the targets displayed on the cross-sectional echo screen are displayed, It becomes difficult to grasp the distance to a target existing at a specific water depth, direction, etc. that the user wants to know. Therefore, in the fourth embodiment, the selection area drawing unit 32 and the selection unit 33 are provided, and the target position that the user wants to monitor is designated and displayed on the horizontal coordinate system.

The horizontal position drawing unit 34 draws the signal of the target selected by the selection unit 33 from the cross-sectional echo screen on the horizontal coordinate system based on the position information and the direction information acquired by the position / orientation information acquisition unit 31. The signal is generated.

The accumulating unit 35 is an accumulating unit that stores and holds information on the past ship position and direction, and the detection area previously generated by the horizontal position drawing unit 34. The information on the ship's own position, direction, and detection area is output to the horizontal position drawing unit 34. The horizontal position drawing unit 34 can match the positional relationship between the current detection area displayed in the horizontal coordinate system and the past detection area based on the position information and the direction information acquired by the position / orientation information acquisition unit 31. Coordinate transformation is performed as follows.

The display unit 36 displays the cross-sectional echo drawing result and the horizontal position drawing result on the display screen, and may display both pieces of information side by side on the same display or separately on different displays. You may make it do. Further, usually only one of the images may be displayed, and both images may be displayed when a display instruction is given from the outside.

Next, the horizontal position drawing by the horizontal position drawing unit 34 will be described in more detail.
10 and 11 are explanatory diagrams for explaining an example of the horizontal position drawing method by the horizontal position drawing unit of the underwater detection device according to the fourth embodiment of the present invention.

FIG. 10 is a diagram showing the detection order of the ship. Assume that the ship detects the front of the ship in the order of (1) to (3) as shown in FIG.
At this time, the horizontal position of the detection area drawn by the horizontal position drawing unit 34 is as shown in FIG.

FIG. 11 is a diagram showing a display image of the horizontal coordinate system displayed by the underwater detection device according to the fourth embodiment of the present invention. 11A is a horizontal position display screen when the search of (1) in FIG. 10 is performed, and FIG. 11B is a horizontal position display when the search of (2) in FIG. 10 is performed. The screen shows a horizontal position display screen when the search in (3) in FIG. 10 is performed.

In this example, the position directly above is always the front position for cross-sectional search. In addition, the left and right widths extending from the position of the ship's tip in the figure correspond to the horizontal pointing angle range of the transducer, and this is indicated by a fan shape centered on the ship.

Each time the position and direction of the ship changes as shown in (1) to (2) of FIG. 10 or (2) to (3) of FIG. The display position in the coordinates is converted, and a drawing signal is generated so that the video of the past detection area stored in the storage unit 35 and the video of the current detection area are displayed in an overlapping manner.

Here, a drawing signal generation method from FIG. 11A to FIG. 11B will be described with reference to FIG.

FIG. 12 is an explanatory diagram for explaining horizontal position drawing signal generation processing by the horizontal position drawing unit of the underwater detection device according to the fourth embodiment of the present invention. FIG. 12A is an explanatory diagram for explaining the display position conversion process when a change in the position of the ship is generated, and FIG. 12B is a description of the display position conversion process when a change in the angle of the ship is generated. FIG. 12C is a diagram showing the display result at the position (2) in FIG. 10 when the ship moves from (1) to (2) in FIG.

The horizontal position drawing unit 34 stores the ship position P1 and the azimuth θ1 of FIG. 10 (1) before the movement, and the difference between the positions of the ship position P2 and the azimuth θ2 of the latest position (2). Is calculated. That is, if the coordinates of (1) and (2) in FIG. 10 are P1 (x1, y1) and P2 (x2, y2), the respective distance differences on the x and y axes between P1 and P2 are:

xd = x2-x1, yd = y2-y1
Therefore, as shown in FIG. 12A, the display image on the past horizontal coordinate system is shifted by the movement distances xd and yd of the ship.

Similarly, regarding the azimuth change, assuming that the azimuths of (1) and (2) in FIG. 10 are θ1 and θ2, the azimuth change from (1) to (2) in FIG.

θd = θ2−θ1
Therefore, as shown in FIG. 12B, the display image on the past horizontal coordinate system is rotated around the origin by the direction change θd of the ship.

Next, as shown in FIG. 12C, drawing is performed for the past directivity angle centered on the point moved in FIG. 12B, and the image of the detection area acquired in FIG. A drawing signal is generated so as to be displayed. As a result, the distance / orientation is the same as when the past image is observed at the position (2) in FIG.

As described above, according to the underwater detection device according to the fourth embodiment of the present invention, the horizontal position drawing unit 34 can display the past video that can be displayed in only one direction of the front cross section by the cross section echo display. Since it can be displayed on the system, the relationship with the past detection area can be easily grasped, and obstacles can be avoided more easily. Also, once you catch a point such as a fishing boat or fishing reef with a fishing boat, even if the ship is swept away by the tide, you can easily return to the original location by manipulating the ship while looking at the point position on the horizontal position display. The effect that can be returned can also be expected.

In the fourth embodiment of the present invention, the upper part of the horizontal position display is taken in the direction of the bow of the ship, but it is also possible to make it a north-up display that is north on the map. In that case, based on the direction information such as a compass, the bow direction may be rotated so that the upper side of the horizontal position display is north.

In the fourth embodiment of the present invention, the selection area drawing unit 32 is provided and a specific target is selected by selecting the selection area marker displayed on the cross-sectional echo screen. For example, the echo of the area arbitrarily selected by the user may be displayed on the horizontal coordinate system.

In the fourth embodiment of the present invention, the selection area displayed on the cross-sectional echo screen is selected by the selection unit 33, and the information on the selected detection area is displayed on the horizontal coordinate system. When it is desired to know only the previously detected range without displaying the symbol, the past detected area is transformed in the horizontal coordinate system and the color of the detected range is changed as shown in FIG. You just have to do it. Note that (1) to (3) in FIG. 13 correspond to the detection areas of (1) to (3) in FIG.

The block diagram for demonstrating the structure of the underwater detection apparatus by Embodiment 1 of this invention. The figure which shows an example of the display image displayed with the underwater detection apparatus by Embodiment 1 of this invention. The figure which shows an example of the display image displayed with the underwater detection apparatus by Embodiment 1 of this invention. The figure which shows an example of the display image displayed with the underwater detection apparatus by Embodiment 1 of this invention. Block diagram for explaining a configuration of an underwater detection device according to a second embodiment of the present invention. Block diagram for explaining a configuration of an underwater detection device according to a third embodiment of the present invention. The figure which shows an example of the display image displayed with the underwater detection apparatus by Embodiment 3 of this invention. Block diagram for explaining a configuration of an underwater detection device according to a fourth embodiment of the present invention. Explanatory drawing for demonstrating an example of the selection area | region marker drawn on a cross-sectional echo screen by the selection area drawing part of the underwater detection apparatus by Embodiment 4 of this invention. Explanatory drawing for demonstrating an example of the technique of the horizontal position drawing by the horizontal position drawing part of the underwater detection apparatus by Embodiment 4 of this invention. The figure which shows an example of the display image of the horizontal coordinate system displayed by the underwater detection apparatus by Embodiment 4 of this invention. Explanatory drawing for demonstrating the production | generation process of the horizontal position drawing signal by the horizontal position drawing part of the underwater detection apparatus by Embodiment 4 of this invention. The figure which shows an example of the display image of the horizontal coordinate system displayed by the underwater detection apparatus by Embodiment 4 of this invention. Explanatory drawing for demonstrating the positional relationship of the conventional ship and an obstruction A diagram showing the positional relationship between the ship and the obstacle over time

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transmission / reception part 2 Cross-section echo drawing part 3 Distance information acquisition part 4 Own ship specific part drawing part 5 Display part 11 Distance information correction part 21 Accumulation part 31 Position / azimuth information acquisition part 32 Selection area drawing part 33 Selection part 34 Horizontal position Drawing unit 35 Storage unit 36 Display unit

Claims (8)

A transmission / reception unit for transmitting / receiving ultrasonic signals;
A cross-sectional echo drawing unit that generates a signal for drawing a cross-sectional echo in the front-rear direction of the ship based on the received signal received by the wave transmitting / receiving unit;
A distance information acquisition unit for acquiring a distance between the installation position of the transmission / reception unit and a specific part of the ship;
Based on the distance information acquired by the distance information acquisition unit, a self-ship specific part display unit that displays a mark indicating a distance difference between the installation position of the transmission / reception unit and the specific part of the own ship on the cross-sectional echo screen An underwater detection device characterized by that. The underwater detection device according to claim 1,
The underwater detection device characterized in that the specific part of the ship is the deepest part of the ship. The underwater detection device according to claim 1,
The specific part of the ship is located in front of or behind the transmission / reception unit,
An underwater detection device comprising a distance information correction unit that changes a distance between an installation position of the transmission / reception unit and a specific part of the ship according to draft. In the underwater detection apparatus in any one of Claim 1 to 3,
The underwater detection device , wherein the mark is a mark line indicating a difference in distance between an installation position of the transmission / reception unit and a specific part of the ship . In the underwater detection apparatus in any one of Claim 1 to 4,
With a storage unit that stores past cross-sectional echo signals,
The underwater detection device, wherein the display unit superimposes and displays the current cross-sectional echo signal generated by the cross-sectional echo drawing unit and at least one past cross-sectional echo signal. The underwater detection device according to claim 4,
The underwater detection device, wherein the mark line is a straight line extending from an installation position of the transmission / reception unit to a specific part of the ship in a direction parallel to or perpendicular to the water surface. The underwater detection device according to claim 4,
The underwater detection device, wherein the mark line is a horizontal line extending from a specific part of the ship in a direction parallel to or perpendicular to the water surface. The underwater detection device according to claim 7,
The underwater detection device, wherein the mark line has a distance scale.