Marine chart information display system, marine chart information display method, and program

Abstract

To provide a marine chart information display system capable of improving discriminability of a deep side and a shallow side with respect to a contour line.SOLUTION: A marine chart information display system comprises: an acquisition section for acquiring marine chart data including lines which constitute contour lines and where a first direction in a width direction expresses a side deeper than the contour line, and a second direction expresses a side shallower than the contour line; a face generation section for generating a first inclined face where a segment is adopted as an upper side and a first lower segment separated downward in the first direction with respect to the segment is adopted as a lower side in a virtual three-dimensional space, so as to arrange a first surface image on the first inclined face; a setting section for setting a virtual camera in the virtual three-dimensional space; and a display section for displaying a virtual sight image which includes the first inclined face with the first surface image arranged thereon and is obtained by plotting a sight within a visual field of the virtual camera.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a nautical chart information display system, a nautical chart information display method, and a program. [Background technology]

[0002] It is known to generate and render three-dimensional display data for displaying a figure showing additional display information superimposed on the water surface of an image output by a photographing device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018 / 216535 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, the chart data for displaying electronic charts includes contour lines such as coastlines or safety contour lines, but simply displaying the contour lines can make it difficult for users to understand the deep and shallow sides of the contour lines.

[0005] Since not all of the contour lines contained in the chart data are closed curves, it is difficult to fill them in, and processing the data so that the contour lines become closed curves is not desirable from the perspective of preventing groundings.

[0006] The present invention has been made in consideration of the above-mentioned problems, and its main purpose is to provide a nautical chart information display system, a nautical chart information display method, and a program that can improve the distinguishability between the deep and shallow sides of contour lines. [Means for solving the problem]

[0007] In order to solve the above problems, one aspect of the present invention provides a nautical chart information display system that includes an acquisition unit that acquires nautical chart data including line segments that form contours and whose first width direction represents a deeper side than the contours and whose second width direction represents a shallower side than the contours, a surface generation unit that generates a first slope in a virtual three-dimensional space, the first slope being an upper side and a first lower line segment that is spaced apart from the first slope in the first direction and downward from the line segment as a lower side, and that places a first surface image on the first slope, a setting unit that sets a virtual camera in the virtual three-dimensional space, and a display unit that displays a virtual scene image that depicts a scene within the field of view of the virtual camera, including the first slope on which the first surface image is placed. This makes it possible to improve the distinguishability between the deep and shallow sides of the contours.

[0008] In the above aspect, the surface generating unit may further generate a second inclined plane having the line segment as its upper side and a second lower line segment that is spaced apart from the line segment in the second direction and downward as its lower side, and place a second surface image on the second inclined plane. This makes it possible to further improve the ability to distinguish between deep and shallow sides of the contour lines.

[0009] In the above aspect, the surface generating unit may further generate an end surface that shares a side with each of the first inclined surface and the second inclined surface, and place a third surface image on the end surface, thereby making it possible to express the three-dimensional effect of the inclined surface.

[0010] In the above aspect, the surface generating unit may generate an intermediate surface that shares a side with each of the two first slopes between the two line segments that are bent in the second direction and connected to each other, and place the first surface image on the intermediate surface, thereby making it possible to express the continuity of the slope.

[0011] In the above aspect, the surface generating unit may add an extension line segment along the closed curve after a final line segment of the plurality of line segments that form the closed curve, and generate the intermediate surface for the final line segment and the extension line segment as well. This makes it possible to represent the continuity of a slope.

[0012] In the above aspect, the first surface image may include a portion adjacent to the line segment that has a higher brightness or saturation than the background of the virtual scene image, thereby improving the visibility of the line segments that make up the contour lines.

[0013] In the above aspect, the first surface image may include a portion in which the brightness or saturation increases toward the line segment, thereby improving the visibility of the line segments that make up the contour lines.

[0014] In the above aspect, the second surface image may have a lower brightness or saturation than the first surface image, which makes it possible to make the second slope less noticeable.

[0015] In the above aspect, the second surface image may be the same color as the background of the virtual scene image, which makes it possible to make the second slope less noticeable.

[0016] In the above aspect, the portion of the third surface image adjacent to the first slope may have higher brightness or saturation than the portion of the third surface image adjacent to the second slope, thereby making it possible to express the three-dimensional effect of the slope.

[0017] In the above aspect, the setting unit may set the virtual camera to a bird's-eye view mode in which the virtual camera faces diagonally downward from a position higher than the virtual water surface, thereby improving the ability to distinguish between deep and shallow sides of the contour lines in the bird's-eye view mode.

[0018] In the above aspect, the apparatus may further include a placement unit that places a ship object representing the ship at a position in the virtual three-dimensional space corresponding to the position of the ship based on the ship position data, thereby making it easier to understand the positional relationship between the depth contours and the ship.

[0019] Another aspect of the nautical chart information display method of the present invention includes acquiring nautical chart data including line segments that form contours and whose first width direction represents a side deeper than the contours and whose second width direction represents a side shallower than the contours, generating a first slope in a virtual three-dimensional space, the first slope being its upper side and a first lower line segment spaced apart from the line segment in the first direction and downward, placing a first surface image on the first slope, setting a virtual camera in the virtual three-dimensional space, and displaying a virtual scene image depicting a scene within the field of view of the virtual camera, including the first slope on which the first surface image is placed. This method makes it possible to improve the distinction between the deep and shallow sides of the contours.

[0020] Another aspect of the present invention provides a program that causes a computer to execute the following steps: acquire nautical chart data including a line segment that forms a bathymetric contour and whose first width direction represents a deeper side than the bathymetric contour and whose second width direction represents a shallower side than the bathymetric contour; generate a first slope in a virtual three-dimensional space, the first slope being its upper side and a first lower line segment that is spaced downward from the first slope in the first direction; place a first surface image on the first slope; set a virtual camera in the virtual three-dimensional space; and generate a virtual scene image that depicts a scene within the field of view of the virtual camera, including the first slope on which the first surface image is placed. This allows for improved discrimination between the deep and shallow sides of the bathymetric contour. [Effects of the Invention]

[0021] According to the present invention, it is possible to improve the discrimination between the deep side and the shallow side of the contour line. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 is a diagram illustrating an example of a ship information display system. [Figure 2] FIG. 10 is a diagram showing an example of a display image. [Figure 3] FIG. 1 is a diagram illustrating an example of a virtual three-dimensional space. [Figure 4] FIG. 10 is a diagram showing an example of a display image. [Figure 5] FIG. 10 is a diagram showing an example of a display image. [Figure 6] FIG. 10 is a diagram showing an example of a display image. [Figure 7] FIG. 2 illustrates an example of a control unit. [Figure 8] FIG. 2 is a diagram illustrating an example of a other ship management database. [Figure 9] FIG. 10 is a diagram illustrating an example of a ship information display method. [Figure 10] FIG. 10 is a diagram illustrating an example of a ship information display method. [Figure 11] FIG. 10 is a diagram for explaining a surface generation process. [Figure 12] FIG. 10 is a diagram for explaining a surface generation process. [Figure 13] FIG. 10 is a diagram for explaining a surface generation process. [Figure 14] FIG. 10 is a diagram for explaining a surface generation process. [Figure 15] FIG. 10 is a diagram for explaining a surface generation process. [Figure 16] FIG. 10 is a diagram for explaining a surface generation process. [Figure 17] FIG. 10 is a diagram for explaining a surface generation process. [Figure 18] FIG. 10 is a diagram for explaining a surface generation process. [Figure 19] FIG. 10 is a diagram for explaining a surface generation process. [Figure 20] FIG. 10 is a diagram for explaining a surface generation process. [Figure 21] FIG. 10 is a diagram for explaining a surface generation process. [Figure 22] FIG. 10 is a diagram for explaining a surface generation process. [Figure 23] FIG. 10 is a diagram for explaining a surface generation process. DETAILED DESCRIPTION OF THE INVENTION

[0023] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this specification and the drawings, elements similar to those described above with reference to the previous drawings will be designated by the same reference numerals, and detailed descriptions thereof may be omitted as appropriate.

[0024] Figure 1 is a block diagram showing an example of the configuration of a navigation information display system 100. The navigation information display system 100 is a system installed on a ship. In the following description, the ship on which the navigation information display system 100 is installed is referred to as the "own ship," and other ships are referred to as "other ships."

[0025] The navigation information display system 100 includes a control unit 1, a display unit 2, a radar 3, an AIS 4, a camera 5, a GNSS receiver 6, a gyrocompass 7, an ECDIS 8, a wireless communication unit 9, and a ship maneuvering control unit 10. These devices are connected to a network N, such as a LAN, and are capable of network communication with each other.

[0026] The control unit 1 includes a computer including a CPU, RAM, ROM, non-volatile memory, an input / output interface, etc. The CPU of the navigation support device 1 executes information processing in accordance with a program loaded from the ROM or non-volatile memory to the RAM.

[0027] The program may be supplied via an information storage medium such as an optical disk or a memory card, or may be supplied via a communication network such as the Internet or a LAN.

[0028] The display unit 2 displays a display image generated by the information processing device 1. The display unit 2 also displays a radar image, a camera image, an electronic nautical chart, or the like.

[0029] The display unit 2 is, for example, a display device with a touch sensor, a so-called touch panel, and detects a position on the screen pointed to by a user's finger, etc. Alternatively, the pointed position may be input by a pointing device such as a trackball.

[0030] The radar 3 emits radio waves around the ship, receives the reflected waves, and generates echo data based on the received signals. The radar 3 also identifies targets from the echo data and generates target tracking data (TT data) that indicates the position and speed of the targets.

[0031] The AIS (Automatic Identification System) 4 receives AIS data from other ships around the ship or from land-based control. Instead of AIS, a VDES (VHF Data Exchange System) may also be used. The AIS data includes the identification codes, names, positions, courses, speeds, types, lengths, and destinations of other ships.

[0032] The camera 5 is a digital camera that captures images of the outside from the ship and generates image data. The camera 5 is installed, for example, on the bridge of the ship, facing the bow direction. The camera 5 is, for example, a so-called PTZ camera that has pan / tilt and optical zoom functions.

[0033] The camera 5 may include an image recognition unit that estimates the position and type of a target, such as a ship, included in a captured image using an object detection model. The image recognition unit is not limited to the camera 5 and may be implemented in another device, such as the control unit 1.

[0034] The GNSS receiver 6 detects the ship's position based on radio waves received from the GNSS (Global Navigation Satellite System). The gyrocompass 7 detects the ship's heading. A GPS compass may be used instead of a gyrocompass.

[0035] An ECDIS (Electronic Chart Display and Information System) 8 acquires the ship's position from the GNSS receiver 6 and displays the ship's position on an electronic chart. The ECDIS 9 also displays the ship's planned route on the electronic chart. A GNSS plotter may be used instead of an ECDIS.

[0036] The wireless communication unit 9 includes wireless equipment for realizing satellite communication and wireless equipment for realizing ship-to-shore or ship-to-ship wireless communication using, for example, ultra-high frequency, very high frequency, short frequency, or medium frequency.

[0037] The ship steering control unit 10 is a control device for realizing autonomous navigation, and controls the steering gear of the ship. The ship steering control unit 10 may also control the engine of the ship.

[0038] In this embodiment, the control unit 1 and the display unit 2 are independent devices, but this is not limiting, and the control unit 1 and the display unit 2 may be an integrated device.

[0039] Furthermore, the control unit 1 is not limited to being an independent device, but may be integrated with another device such as the ECDIS 8. In other words, some or all of the functions of the control unit 1 may be realized by another device.

[0040] Furthermore, the display unit 2 is not limited to being an independent device, and a display unit of another device such as the ECDIS 8 may be used as the display unit 2 that displays the display image generated by the control unit 1.

[0041] Furthermore, the control unit 1 and the display unit 2 may be installed in a land-based control center, for example, and used to monitor ships sailing in a controlled sea area.

[0042] Fig. 2 is a diagram showing an example of a display image MG generated by the control unit 1 and displayed on the display unit 2. Fig. 3 is a diagram showing an example of a virtual three-dimensional space VS for generating a virtual scene image VG included in the display image MG. Figs. 4 to 6 are diagrams showing more specific examples of the display image MG.

[0043] The control unit 1 sequentially generates display images MG for each point in time based on data acquired from other devices such as radar 3, AIS 4, camera 5, and GNSS receiver 6, and outputs moving image data including the time-series display images MG to the display unit 2.

[0044] The display image MG mainly includes a virtual scene image VG. The virtual scene image VG is an image depicting the scene within the field of view of a virtual camera VC set in a virtual three-dimensional space VS. Figures 2 and 3 show an example of a bird's-eye view mode in which the virtual water surface SS is viewed diagonally downward from a predetermined height.

[0045] The virtual three-dimensional space VS has a coordinate system that corresponds to the real space. The height of the virtual water surface SS corresponds to the height of the water surface in the real space (for example, 0 m above sea level).

[0046] Ship objects X are placed on the virtual water surface SS. The ship objects X are three-dimensional objects. The ship objects X include a ship object X1 (also called "own ship object X1") representing the player's own ship, and a ship object X2 (also called "other ship object X2") representing another ship.

[0047] The own ship object X1 and the other ship object X2 are displayed so as to be distinguishable from each other, for example, in terms of color, shape, texture, or the like.

[0048] The own ship object X1 is placed at a position on the virtual water surface SS that corresponds to the own ship's two-dimensional position in real space. The own ship object X1 has a shape that resembles a ship, and its heading can be determined from its appearance.

[0049] The other ship object X2 is also placed at a position on the virtual water surface SS that corresponds to the two-dimensional position of the other ship in real space. The other ship object X2 has various shapes and sizes. Examples of the other ship object X2 include the other ship object X2c shaped like a ship and the button-shaped object X2b.

[0050] In the virtual three-dimensional space VS, concentric circles CC are arranged with the own ship object X1 at the center. Character strings DT1 and DT2 indicating distances are added to the concentric circles CC. A scale and numerical values ​​indicating the direction may be added to the outermost ring of the concentric circles CC.

[0051] Also arranged in the virtual three-dimensional space VS are a route object RT indicating the planned route of the ship, and a waypoint object WP indicating a waypoint on the planned route.

[0052] Additionally, a coastline ZC and safety contour lines SC are arranged in the virtual three-dimensional space VS. The coastline ZC and safety contour lines SC are examples of contour lines and are created based on nautical chart data. The nautical chart data is, for example, ENC (Electronic Navigational Chart) data.

[0053] The coastline ZC is a contour line that indicates 0m above sea level and marks the boundary between the sea and land. The safety contour SC is a contour line that indicates the minimum water depth required for a ship to navigate safely, and is determined based on factors such as the size of the ship.

[0054] In addition, the virtual three-dimensional space VS may further include a mark indicating the intersection of the display line of sight and the virtual water surface SS, an object indicating the echo intensity detected by the radar 4, or a range circle indicating the detection range of the radar 4.

[0055] In addition to the virtual scene image VG, the display image MG also includes a compass object DR and buttons B6 to B9 etc. The compass object DR is an object that indicates directions such as north and south like a compass.

[0056] Button B6 is a button for switching the direction corresponding to the top of the virtual scene image VG between the ship's bow direction (H-UP) and north direction (N-UP). Figure 2 shows an example in which the top of the virtual scene image VG corresponds to the ship's bow direction.

[0057] Button B7 is a button for switching the display viewpoint to top view mode, button B8 is a button for switching the display viewpoint to bird's-eye view mode, and button B9 is a button for switching the display viewpoint to bridge view mode.

[0058] Figures 4 and 5 show examples of the bird's-eye view mode, with Figure 5 showing an enlarged example of a portion including the coastline ZC and the safety contour line SC, and Figure 6 shows an example of the top-view mode.

[0059] However, when contour lines such as coastlines ZC and safety contour lines SC are simply displayed, it can be difficult for the user to grasp the deeper and shallower sides of the contour lines.

[0060] Because not all contour lines are closed curves, it is difficult to distinguish between the deep and shallow sides of the contour lines. Furthermore, processing the data so that the contour lines become closed curves, or adding separate closed curve data for the purpose of distinguishing between them, is undesirable from the perspective of both preventing strandings, which is the original purpose, and reducing the amount of data.

[0061] Therefore, in this embodiment, as described below, a surface generation process is performed to add a slope F1 (see Figure 5) to contour lines such as the coastline ZC or safety contour lines SC, thereby improving the ability to distinguish between the deep and shallow sides of the contour lines with a smaller amount of data.

[0062] An example of the configuration and operation of the control unit 1 that generates the display image MG will be described below.

[0063] Figure 7 is a block diagram showing an example of the configuration of the control unit 1. The control unit 1 includes an own ship data acquisition unit 11, an other ship data acquisition unit 12, an input reception unit 13, a nautical chart data acquisition unit 14, a virtual space management unit 15, an object placement unit 16, a camera setting unit 17, a plane generation unit 18, and an image generation unit 19. These functional units are realized by the CPU of the control unit 1 executing information processing in accordance with a program.

[0064] The ship data acquisition unit 11 acquires ship data including the ship's position and speed. Speed ​​is a vector quantity expressed by ship speed and direction, and ship speed is a scalar quantity. Direction is the course, but may also be the heading (heading). Position is expressed in geographic coordinates that represent a two-dimensional position in real space.

[0065] Specifically, the ship data acquisition unit 11 successively acquires the ship's position detected by the GNSS receiver 6 and calculates the ship's speed from changes in the ship's position over time. However, the ship's speed may be acquired from a ship's speedometer (not shown), and the ship's direction may be acquired from the gyrocompass 7.

[0066] The other ship data acquisition unit 12 acquires other ship data, including the position and speed of each of multiple other ships present around the ship. The other ship data is generated based on data detected by the radar 3, AIS 4, or camera 5 installed on the ship. The other ship data may also be acquired from an external source via wireless communication.

[0067] Specifically, the other ship data acquisition unit 12 sequentially acquires, as other ship data, the TT data generated by the radar 3, the AIS data received by the AIS 4, or the identification data identified from the images captured by the camera 5. The other ship data acquisition unit 12 registers the acquired other ship data in a other ship management database constructed in memory.

[0068] As shown in Figure 8, the other ship management database includes fields such as "Ship ID," "Source," "Position," "Ship Speed," and "Direction." "Ship ID" is an identifier assigned to other ships. "Source" indicates whether the other ship data was generated by the radar 3, the AIS 4, or the camera 5.

[0069] "Position" indicates the position of the other ship. The position of the other ship is expressed as latitude and longitude. The position of the other ship detected by the radar 3 or camera 5 is a relative position to the own ship, so it is converted to an absolute position using the position of the own ship detected by the GNSS receiver 6.

[0070] "Ship speed" indicates the speed of the other ship. "Direction" indicates the direction of the other ship. The speed and direction of the other ship detected by the radar 3 or camera 5 are estimated from the change in the position of the other ship in the image over time.

[0071] In addition, if the position of other ship data sourced from one of AIS 3, radar 4, and camera 5 is the same as or similar to the position of other ship data sourced from another one of them, the other ship data will be combined into one record as being related to a common other ship.

[0072] In this embodiment, other ships detected by AIS 3, radar 4, or camera 5 are managed as display objects, but this is not limited to this, and targets other than other ships, such as buoys, icebergs, or floating containers, detected by radar 4 or camera 5, may also be displayed as objects.

[0073] Returning to the explanation of Fig. 7, the input receiving unit 13 receives an operation input by a user. Specifically, the input receiving unit 13 acquires input data representing the operation input by the user detected by the touch sensor of the display unit 2, and interprets the command content corresponding to the operation input.

[0074] The operation input by the user is, for example, an operation input for selecting a ship object X included in the display image MG, pressing buttons B6 to B9, or adjusting the viewpoint position or line of sight direction of the virtual camera VC.

[0075] The nautical chart data acquisition unit 14 acquires nautical chart data for displaying the coastline ZC and the safety contour lines SC. In this embodiment, the nautical chart data is acquired from an external server via the wireless communication unit 9. However, the nautical chart data is not limited to this, and may be stored in the memory of the control unit 1.

[0076] The virtual space management unit 15 manages the virtual three-dimensional space VS (see FIG. 3), and receives the placement of the ship object X, etc., the setting of the virtual camera VC, and the placement of the coastline ZC and safety contour line SC.

[0077] The object placement unit 16 places a ship object X at a position in the virtual three-dimensional space VS that corresponds to the position of the ship, based on the position data of the ship (see FIG. 3).

[0078] Specifically, based on the own ship data acquired by the own ship data acquisition unit 11, the object placement unit 16 places an own ship object X1 shaped like a ship at a position on the virtual water surface SS corresponding to the two-dimensional position of the own ship in real space, in an orientation corresponding to the own ship's course.

[0079] Furthermore, based on the other ship data acquired by the other ship data acquisition unit 12, the object placement unit 16 places the other ship object X2 at a position on the virtual water surface SS that corresponds to the two-dimensional position of the other ship in real space.

[0080] Specifically, the object placement unit 16 places a ship object X2c shaped like a ship in a direction corresponding to the bow direction for another ship detected by the AIS 3. The other ship object X2c is formed in a shape or size according to the type of ship or hull length.

[0081] Furthermore, the object placement unit 16 places a button-shaped other ship object X2b for another ship detected by the radar 4 or the camera 5. The object placement unit 16 may change the appearance of the other ship object X2 depending on the detection reliability.

[0082] The camera setting unit 17 sets a virtual camera VC in the virtual three-dimensional space VS. The camera setting unit 17 adjusts the viewpoint position and line of sight direction of the virtual camera VC. The viewpoint of the virtual camera VC is also called the display viewpoint, and the line of sight of the virtual camera VC is also called the display line of sight.

[0083] The camera setting unit 17 sets the virtual camera VC to a top view mode, a bird's-eye view mode, or a bridge view mode in response to the user pressing any of the buttons B7 to B9.

[0084] In the top view mode, the virtual camera VC is set to look directly down on the own ship object X1 from a position higher than the virtual water surface SS, while in the bird's-eye view mode, the virtual camera VC is set to look diagonally down on the own ship object X1 from a position higher than the virtual water surface SS.

[0085] In the top view mode or bird's-eye view mode, the viewpoint position and viewing direction of the virtual camera VC are set so that the own ship object X1 is located at the center of the field of view. In the bridge view mode, the virtual camera VC is set so that it views the course from a position corresponding to the wheelhouse of the own ship object X1.

[0086] The camera setting unit 17 sets a camera tracking mode in which the virtual camera VC moves in accordance with the movement of the own ship object X1. That is, the camera setting unit 17 causes the virtual camera VC to track the own ship object X1 while maintaining the position and attitude of the virtual camera VC relative to the own ship object X1.

[0087] The camera setting unit 17 can also set a camera fixed mode in which the camera does not follow the own ship object X1. In this case, the camera setting unit 17 adjusts the viewpoint position, line of sight direction, viewing angle, magnification rate, etc. of the virtual camera VC in response to operation input by the user.

[0088] The surface generation unit 18 performs a surface generation process that adds a slope to the coastline ZC or the safety contour line SC arranged in the virtual three-dimensional space VS to improve the distinction between the deep side and the shallow side. The surface generation process will be described in detail later.

[0089] The image generation unit 19 generates a virtual scene image VG that depicts a scene within the field of view of the virtual camera VC in the virtual three-dimensional space VS, and outputs a display image MG that includes the virtual scene image VG to the display unit 2.

[0090] 9 and 10 are flow diagrams mainly showing an example of the procedure related to the surface generation processing of the ship information display method realized in the ship information display system 100. The control unit 1 of the ship information display system 100 executes the information processing shown in the figures in accordance with a program. The processing shown in the figures is executed, for example, every time the display viewpoint or display line of sight changes, or periodically.

[0091] 11 to 23 are diagrams for explaining the plane generation process. In the drawings, the X1-X2 and Y1-Y2 directions represent the horizontal direction, and the Z1-Z2 direction represents the vertical direction. The Z1 direction is the upward direction, and the Z2 direction is the downward direction.

[0092] The Y1-Y2 direction represents the extension direction of the line segment SG that constitutes the contour line. The X1-X2 direction represents the width direction of the line segment SG. Within the width direction of the line segment SG, the X1 direction represents the deeper side than the contour line, and the X2 direction represents the shallower side than the contour line. The X1 direction is also called the outward direction relative to the contour line, and the X2 direction is also called the inward direction relative to the contour line.

[0093] 9, first, the control unit 1 acquires nautical chart data (S11, processing as the nautical chart data acquisition unit 14). Specifically, the control unit 1 acquires nautical chart data for the sea area to which the ship's position belongs from an external server via the wireless communication unit 9.

[0094] Next, the control unit 1 places a coastline ZC and safety contour lines SC in the virtual three-dimensional space VS based on the acquired nautical chart data (S12, processing as the virtual space management unit 15). Each of the coastline ZC and safety contour lines SC is composed of a number of line segments SG.

[0095] 11, one line segment SG has a start point E1 and an end point E2, and is defined by the coordinates of the start point E1 and the end point E2. Furthermore, the line segment SG has attributes of an outward direction (X1 direction) and an inward direction (X2 direction) relative to the line segment SG.

[0096] Next, the control unit 1 determines whether or not the coastline ZC or the safety contour SC includes a closed curve, i.e., whether or not the coastline ZC or the safety contour SC includes a plurality of line segments SG that form a closed curve (S13). The processing when a closed curve is included will be described later.

[0097] Next, the control unit 1 selects one line segment SG (S14), and performs a surface generation process for the selected line segment SG (S15 to S24, processing as the surface generation unit 18).

[0098] Specifically, the control unit 1 places an outer-lower line segment LG1 spaced outward (in the X1 direction) and downward (in the Z2 direction) from the line segment SG (S15), and generates an outer slope F1 with the line segment SG as its upper side and the outer-lower line segment LG1 as its lower side (S16, see FIG. 12). The outer-lower line segment LG1 is an example of a first lower line segment, and the outer slope F1 is an example of a first slope.

[0099] The outer slope F1 is a quadrangle formed by a line segment SG, a downward outer line segment LG1, and a pair of side edges YG1. The angle θ of the outer slope F1 with respect to the vertical plane and the distance between the line segment SG and the downward outer line segment LG1 are not particularly limited. In the illustrated example, the downward outer line segment LG1 is parallel to the line segment SG and has the same length as the line segment SG, and the outer slope F1 is rectangular, but this is not limiting.

[0100] Next, the control unit 1 places an inner lower line segment LG2 spaced inward (X2 direction) and downward (Z2 direction) from the line segment SG (S17), and generates an inner slope F2 with the line segment SG as its upper side and the inner lower line segment LG2 as its lower side (S18, see FIG. 13). The inner lower line segment LG2 is an example of a second lower line segment, and the inner slope F2 is an example of a second slope.

[0101] The inner slope F2 is a quadrangle formed by a line segment SG, an inner lower line segment LG2, and a pair of side edges YG2. The angle θ of the inner slope F2 with respect to the vertical plane and the distance between the line segment SG and the inner lower line segment LG2 are not particularly limited and may differ from those of the outer slope F1. In the illustrated example, the inner lower line segment LG2 is parallel to and has the same length as the line segment SG, and the inner slope F2 is rectangular, but is not limited thereto.

[0102] Next, the control unit 1 generates end faces FE at both ends of the line segment SG in the extension direction (Y1-Y2 direction) (S19, see FIG. 14). The end face FE shares a side YG1 with the outer slope F1 and a side YG2 with the inner slope F2. In other words, the outer slope F1 and the end face FE share a side YG1, and the inner slope F2 and the end face FE share a side YG2. The end face FE is a triangle formed by the side YG1, the side YG2, and the bottom side LG3.

[0103] As shown in Figure 10, the control unit 1 then places an outer surface image G1 on the outer slope F1 (S20, see Figure 16), an inner surface image G2 on the inner slope F2 (S21, see Figure 17), and an end surface image G3 on the end surface FE (S22, see Figure 18).

[0104] The arrangement of the outer surface image G1, the inner surface image G2, and the end surface image G3 is what is called texture mapping. The outer surface image G1 is an example of a first surface image, the inner surface image G2 is an example of a second surface image, and the end surface image G3 is an example of a third surface image.

[0105] 16, the outer surface image G1 has a higher brightness or saturation overall than the inner surface image G2. Specifically, the outer surface image G1 includes a high-brightness area G1W adjacent to the line segment SG, which has a higher brightness or saturation than the background of the virtual scene image VG. The high-brightness area G1W is the same color as the coastline ZC or the safety contour line SC.

[0106] The outer surface image G1 also includes a low-brightness area G1B adjacent to the outer-lower line segment LG1, which has a lower brightness or saturation than the high-brightness area G1W. The low-brightness area G1B has the same color as the background of the virtual scene image VG. The background of the virtual scene image VG is, for example, black (see FIGS. 4 to 6).

[0107] Furthermore, the outer surface image G1 includes a transition portion G1T between the high-brightness portion G1W and the low-brightness portion G1B, where the brightness or saturation increases toward the line segment SG. The transition portion G1T gradually changes color from the same color as the low-brightness portion G1B to the same color as the high-brightness portion G1W as it moves upward.

[0108] By arranging such an outer surface image G1 on the outer slope F1, it is possible to improve the visibility of the coastline ZC and the safety contour line SC, especially by including the high-brightness portion G1W in the outer surface image G1 (see FIG. 23). Furthermore, by including the transition portion G1T in the outer surface image G1, it is possible to make the outer slope F1 blend in with the background of the virtual scene image VG.

[0109] 17, the inner surface image G2 has a lower brightness or saturation overall than the outer surface image G1. Specifically, the inner surface image G2 has the same color as the background of the virtual scene image VG.

[0110] By placing such an inner surface image G2 on the inner slope F2, it is possible to improve the visibility of the coastline ZC and the safety contour line SC (see Fig. 23). That is, as shown in Fig. 15, the difference in brightness or saturation between the inside and outside of the line segment SG becomes large, and the line segment SG is emphasized.

[0111] Furthermore, by making the inner surface image G2 the same color as the background of the virtual scene image VG, the entire inside of the coastline ZC or safety contour line SC will be the same color, as shown in Figure 23, making it possible to represent land or shallow waters.

[0112] 18, the outer portion G31 adjacent to the outer slope F1 of the end face surface image G3 has higher brightness or saturation overall than the inner portion G32 adjacent to the inner slope F2. The outer half of the end face surface image G3 is the outer portion G31, and the inner half is the inner portion G32.

[0113] Specifically, the outer portion G31 of the end surface image G3 has the same color as the outer surface image G1, and includes a high-brightness portion G1W, a transition portion G1T, and a low-brightness portion G1B, just like the outer surface image G1. The inner portion G32 of the end surface image G3 has the same color as the inner surface image G2.

[0114] By placing such an end face surface image G3 on the end face FE, even if the coastline ZC or safety contour line SC is interrupted, it is possible to provide continuity between the outer slope F1 and the end face FE, so that the outer slope F1 does not appear to be suddenly interrupted.

[0115] As shown in FIG. 10, next, if the selected line segment SG and the previous line segment SG connected to it are bent inward at the connection point (S23: YES), the control unit 1 generates an intermediate plane FM that shares a side YG1 with each of the outer slopes F1 of those line segments SG (S24), and places the outer surface image G1 on the generated intermediate plane FM (S25).

[0116] Specifically, as shown in Figure 19, when the line segment SG between points E1 and E2 and the line segment SG between points E2 and E3 are connected to each other at point E2 and bent inward (toward the shallower side), the two end faces FE intersect at point E2, and a notch NC exists between the two outer slopes F1.

[0117] Therefore, as shown in Figure 20, the control unit 1 generates an intermediate plane FM that shares a side YG1 on the point E2 side with each of the two outer slopes F1, and places an outer surface image G1 that is the same as the outer slope F1 on the generated intermediate plane FM.

[0118] That is, the control unit 1 generates an intermediate surface FM covering the cutout NC between the side YG1 on the point E2 side of the outer slope F1 located between points E1 and E2 and the side YG1 on the point E2 side of the outer slope F1 located between points E2 and E3, thereby making the cutout NC invisible.

[0119] By providing an intermediate surface FM between the two outer slopes F1 in this way, it is possible to give continuity to the two outer slopes F1 so that there does not appear to be a gap between the two outer slopes F1.

[0120] In addition, not only when the line segment SG between points E1-E2 and the line segment SG between points E2-E3 are bent inward, but also when they are bent outward, an intermediate surface that shares a side YG2 with each of the two inner slopes F2 may be generated, and an inner surface image G2 identical to the inner slope F2 may be placed on the generated intermediate surface.

[0121] However, as mentioned above, the inner surface image G2 and the inner portion G32 of the end surface image G3 are the same color as the background of the virtual scene image VG, and even if a cutout is present, it is not noticeable. Therefore, if the two line segments are bent outward, the generation of an intermediate surface may be omitted.

[0122] 10, the control unit 1 then determines whether or not the surface generation process has been performed for all line segments SG (S26). If the surface generation process has not been performed for all line segments SG (S26: NO), the control unit 1 selects the next line segment SG (S27) and performs the surface generation process for the newly selected line segment SG (S15 to S24).

[0123] When the surface generation process has been performed for all line segments SG (S26: YES), the control unit 1 generates a virtual scene image VG (S28: processing as the image generation unit 19). The virtual scene image VG generated in this manner includes the coastline ZC or the safety contour line SC, as well as the outer slope F1, inner slope F2, end face FE, and intermediate face FM.

[0124] The process in S13 above when the coastline ZC or the safety contour SC includes a closed curve will be described. If the coastline ZC or the safety contour SC includes a closed curve (S13: YES), the control unit 1 adds an extension line segment to the multiple line segments SG that make up the closed curve (S29).

[0125] Specifically, as shown in Fig. 21, the closed curve is formed by a line segment SG between points E1 and E2, a line segment SG between points E2 and E3, a line segment SG between points E3 and E4, and a line segment SG between points E4 and E5. Whether or not a curve is a closed curve is determined by whether or not the first point E1 and the last point E5 of the points E1-E5 that define the multiple line segments SG are in the same position.

[0126] In steps S15 and S16, outer slopes F1 are generated for the line segment SG between points E1 and E2, the line segment SG between points E2 and E3, the line segment SG between points E3 and E4, and the line segment SG between points E4 and E5.

[0127] Furthermore, since these line segments SG are bent inward, intermediate surfaces FM are generated by steps S23-S25 between the two outer slopes F1 at point E2, between the two outer slopes F1 at point E3, and between the two outer slopes F1 at point E4.

[0128] However, at points E1 and E5, the line segment SG between points E1 and E2 and the line segment SG between points E4 and E5 are not connected to each other, so no intermediate surface FM is generated and the notch NC remains.

[0129] Therefore, as shown in FIG. 22, the control unit 1 adds a line segment SG between points E5 and E6 along the closed curve as an extension line segment after the line segment SG between points E4 and E5, which is the final line segment among the line segments SG that make up the closed curve (S29).

[0130] Specifically, the control unit 1 adds a new point E6 at the same position as the next point E2 after the first point E1, thereby adding a line segment SG between points E5 and E6 that overlaps with the first line segment SG between points E1 and E2.

[0131] As a result, S15 and S16 generate an outer slope F1 for the line segment SG between points E5 and E6, which is an extended line segment, and further, S23-S25 generate intermediate surfaces FM for the line segment SG between points E4 and E5 and the line segment SG between points E5 and E6.

[0132] That is, an intermediate surface FM covering the cutout NC is generated between the side YG1 on the point E5 side of the outer slope F1 located between points E4 and E5 and the side YG1 on the point E5 side of the outer slope F1 located between points E5 and E6, making the cutout NC invisible.

[0133] According to the embodiment described above, by adding an outer slope F1, an inner slope F2, an end surface FE, an intermediate surface FM, etc. to the coastline ZC or the safety contour line SC, it is possible to improve the distinguishability between the deep and shallow sides of the coastline ZC or the safety contour line SC.

[0134] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made by those skilled in the art.

[0135] For example, the generation of the inner slope F2 may be omitted, and the outer surface image G1 may be placed on the outer surface facing outward of the outer slope F1, and the inner surface image G2 may be placed on the inner surface facing inward of the outer slope F1. This also makes it possible to achieve the same representation as in the above embodiment.

[0136] Representative embodiments of the present invention will be listed below.

[0137] (1) An acquisition unit that acquires nautical chart data including line segments that form contour lines, with a first direction in the width direction representing a side deeper than the contour lines and a second direction representing a side shallower than the contour lines; a surface generating unit that generates, in a virtual three-dimensional space, a first inclined surface having the line segment as its upper side and a first lower line segment that is spaced apart from the line segment in the first direction and in a downward direction as its lower side, and places a first surface image on the first inclined surface; a setting unit for setting a virtual camera in the virtual three-dimensional space; a display unit that displays a virtual scene image that depicts a scene within the field of view of the virtual camera, including the first inclined surface on which the first surface image is arranged; A nautical chart information display system comprising:

[0138] (2) the surface generating unit further generates a second inclined surface having the line segment as an upper side and a second lower line segment that is spaced apart from the line segment in the second direction and in a downward direction as a lower side, and places a second surface image on the second inclined surface. (1) A nautical chart information display system.

[0139] (3) the surface generation unit further generates an end surface that shares a side with each of the first inclined surface and the second inclined surface, and places a third surface image on the end surface. (2) A nautical chart information display system.

[0140] (4) the surface generation unit generates an intermediate surface that shares a side with each of the two first slopes of the two line segments that are bent in the second direction and connected to each other, and places the first surface image on the intermediate surface. A nautical chart information display system described in any of (1) to (3).

[0141] (5) the surface generation unit adds an extension line segment along the closed curve after a final line segment among the plurality of line segments constituting the closed curve, and generates the intermediate surface for the final line segment and the extension line segment as well. (4) A nautical chart information display system as described above.

[0142] (6) the first surface image includes a portion adjacent to the line segment that has a higher brightness or saturation than the background of the virtual scene image; A nautical chart information display system described in any of (1) to (5).

[0143] (7) the first surface image includes a portion whose brightness or saturation increases toward the line segment; A nautical chart information display system described in any of (1) to (6).

[0144] (8) the second surface image has a lower brightness or saturation than the first surface image; A nautical chart information display system as described in (2) or (3).

[0145] (9) the second surface image is the same color as the background of the virtual scene image; A nautical chart information display system as set forth in (2), (3) or (8).

[0146] (10) a portion of the third surface image adjacent to the first slope has a higher brightness or saturation than a portion of the third surface image adjacent to the second slope; (3) A nautical chart information display system as described above.

[0147] (11) the setting unit sets the virtual camera to a bird's-eye view mode in which the virtual camera faces obliquely downward from a position higher than the virtual water surface. A nautical chart information display system according to any one of (1) to (10).

[0148] (12) a placement unit that places a ship object representing the ship at a position in the virtual three-dimensional space that corresponds to the position of the ship based on position data of the ship; A nautical chart information display system according to any one of (1) to (11).

[0149] (13) Acquire nautical chart data including a line segment that forms a contour line and has a first width direction that represents a side deeper than the contour line and a second width direction that represents a side shallower than the contour line; In the virtual three-dimensional space, a first slope is generated, the first slope having the line segment as an upper side and a first lower line segment that is spaced apart from the line segment in the first direction and in a downward direction as a lower side; disposing a first surface image on the first bevel; A virtual camera is set in the virtual three-dimensional space, displaying a virtual scene image depicting a scene within the field of view of the virtual camera, including the first inclined surface on which the first surface image is disposed; How to display chart information.

[0150] (14) Acquiring nautical chart data including line segments that form contour lines, with a first direction in the width direction representing a side deeper than the contour lines and a second direction representing a side shallower than the contour lines; generating, in a virtual three-dimensional space, a first inclined plane having the line segment as its upper side and a first lower line segment spaced apart from the line segment in the first direction and in a downward direction as its lower side, and arranging a first surface image on the first inclined plane; Setting a virtual camera in the virtual three-dimensional space; and generating a virtual scene image depicting a scene within the field of view of the virtual camera, including the first slope on which the first surface image is disposed; A program that causes a computer to execute the following. [Explanation of symbols]

[0151] 1 control unit, 2 display unit, 3 radar, 4 AIS, 5 camera, 6 GNSS receiver, 7 gyrocompass, 8 ECDIS, 9 wireless communication unit, 10 ship maneuvering control unit, 11 own ship data acquisition unit, 12 other ship data acquisition unit, 13 input reception unit, 14 nautical chart data acquisition unit, 15 virtual space management unit, 16 object placement unit, 17 camera setting unit, 18 surface generation unit, 19 image generation unit, 100 ship information display system

Claims

1. an acquisition unit that acquires nautical chart data including line segments that form contour lines, with a first direction in the width direction representing a side deeper than the contour lines and a second direction representing a side shallower than the contour lines; a surface generating unit that generates, in a virtual three-dimensional space, a first inclined surface having the line segment as an upper side and a first lower line segment that is spaced apart from the line segment in the first direction and in a downward direction as a lower side, and places a first surface image on the first inclined surface; a setting unit for setting a virtual camera in the virtual three-dimensional space; a display unit that displays a virtual scene image that depicts a scene within the field of view of the virtual camera, including the first slope on which the first surface image is arranged; A nautical chart information display system comprising:

2. the surface generating unit further generates a second inclined surface having the line segment as an upper side and a second lower line segment spaced apart from the line segment in the second direction and in a downward direction as a lower side, and places a second surface image on the second inclined surface. The nautical chart information display system according to claim 1.

3. the surface generation unit further generates an end surface sharing a side with each of the first inclined surface and the second inclined surface, and places a third surface image on the end surface.

3. The nautical chart information display system according to claim 2.

4. the surface generation unit generates an intermediate surface that shares a side with each of the two first slopes of the two line segments that are bent in the second direction and connected to each other, and places the first surface image on the intermediate surface. The nautical chart information display system according to claim 1.

5. the surface generation unit adds an extension line segment along the closed curve after a final line segment among the plurality of line segments constituting the closed curve, and generates the intermediate surface for the final line segment and the extension line segment as well.

5. A nautical chart information display system according to claim 4.

6. the first surface image includes a portion adjacent to the line segment that has a higher brightness or saturation than the background of the virtual scene image; The nautical chart information display system according to claim 1.

7. the first surface image includes a portion whose brightness or saturation increases toward the line segment; The nautical chart information display system according to claim 1.

8. the second surface image has a lower brightness or saturation than the first surface image; 3. The nautical chart information display system according to claim 2.

9. the second surface image is the same color as the background of the virtual scene image; 3. The nautical chart information display system according to claim 2.

10. a portion of the third surface image adjacent to the first slope has a higher brightness or saturation than a portion of the third surface image adjacent to the second slope; The nautical chart information display system according to claim 3.

11. the setting unit sets the virtual camera to a bird's-eye view mode in which the virtual camera faces obliquely downward from a position higher than the virtual water surface. The nautical chart information display system according to claim 1.

12. a placement unit that places a ship object representing the ship at a position in the virtual three-dimensional space that corresponds to the position of the ship based on position data of the ship; The nautical chart information display system according to claim 1.

13. Acquire nautical chart data including line segments that form contour lines, with a first direction in the width direction representing a side deeper than the contour lines and a second direction representing a side shallower than the contour lines; generating, in a virtual three-dimensional space, a first slope having the line segment as an upper side and a first lower line segment spaced apart from the line segment in the first direction and in a downward direction as a lower side; A first surface image is disposed on the first slope; a virtual camera is set in the virtual three-dimensional space; displaying a virtual scene image depicting a scene within the field of view of the virtual camera, including the first slope on which the first surface image is disposed; How to display chart information.

14. acquiring nautical chart data including line segments that form contour lines, the first direction of which in the width direction represents a side deeper than the contour lines, and the second direction of which in the width direction represents a side shallower than the contour lines; generating, in a virtual three-dimensional space, a first inclined plane having the line segment as an upper side and a first lower line segment spaced apart from the line segment in the first direction and in a downward direction as a lower side, and arranging a first surface image on the first inclined plane; Setting a virtual camera in the virtual three-dimensional space; and generating a virtual scene image depicting a scene within a field of view of the virtual camera, including the first slope on which the first surface image is disposed; A program that causes a computer to execute the following.

Images