JP2007078774A - Vehicle guiding device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a map display device capable of displaying a bird's-eye view according not only to the traveling state of a vehicle but also to user's circumstances and user's requests. <P>SOLUTION: In a vehicle guiding device, a bird's-eye view is drawn by using map data including positional information of roads, facilities and the like. The bird's-eye view to be drawn is so constituted that a plurality of rectangular parts with a depression angle different from each other are vertically arrayed so that the land is successively shown. The vehicle guiding device comprises: a recording section to record map data; a control section to read a part of the map data and convert it for the purpose of displaying a bird's-eye view; and a drawing section to create picture data of the bird's-eye view by using a part of the converted map data. When the view looking down at the land is divided into a plurality of rectangular parts, the control section reads map data from a recoding section and converts the data so that a bird's eye view looking down at the land with the angle set for each rectangular part is created. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vehicle guidance device such as a car navigation device that displays an overhead view for guidance of a vehicle.

  In a car navigation device, a bird's-eye view (bird's-eye view) is displayed to show the user the geographical situation related to the surroundings of the vehicle in an easy-to-understand manner. FIG. 4A is an explanatory diagram showing a method for creating an overhead view in a conventional car navigation apparatus. The ground overlooked is in the XY plane. The overhead viewpoint S is determined from the current position P of the vehicle obtained by receiving a GPS (Global Positioning System) signal, a preset depression angle φ, and the like. The overhead view is usually drawn so as to include the vehicle, and the viewpoint S is determined so that the current position P of the vehicle is viewed toward the destination, for example.

  The geographical range overlooked is a trapezoidal area ABCD in which a quadrangular pyramid having the viewpoint S as a vertex and a rectangular abcd defining the field of view intersects the XY plane. The overhead view displayed is understood as a mapping of the trapezoidal area ABCD to the rectangle abcd. The angle at which the straight line passing through the viewpoint S and the center of the rectangle abcd intersects the XY plane is the depression angle φ. In the bird's-eye view created in this way, the region farther from the viewpoint S is drawn at a smaller scale, and the smaller the depression angle φ, the larger the geographical region to be drawn. As is well known, the overhead view displayed on the display unit is appropriately updated in accordance with the traveling of the vehicle.

When driving on urban roads with many intersections at low speeds, it is preferable to display a bird's eye view showing the situation in the vicinity of the vehicle in detail, and when driving on highways at high speeds, a wide geographical area is displayed. Since it is preferable to display an overhead view, there has been proposed a car navigation device that changes the depression angle φ of the overhead view according to the type of road on which the vehicle is traveling (see Patent Document 1). In this car navigation device, the depression angle φ is increased when the road on which the vehicle is traveling is a general road (for example, 60 °), and is decreased when the road is a highway (for example, 20 °).
JP 2000-74678 A

  There are various situations where the user who drives the vehicle is placed and the user's desires. For example, even when traveling on a road in an urban area at a low speed, it may occur when it is desired to grasp the position of a relatively far destination with an overhead view. Further, even if the vehicle is traveling on a highway at a high speed, a very distant area does not have to be displayed. Therefore, it is possible to increase the scale of the distant area displayed in the overhead view. However, in the car navigation device described above, in such a case, it is impossible to respond to the user's request and display an overhead view that appropriately corresponds to the traveling state of the vehicle. For example, if the depression angle φ is reduced in the former case, detailed information about the vicinity of the vehicle position P is not displayed, which causes a problem in guiding the vehicle. Further, when the depression angle φ is increased in the latter case, the overhead view is excessively updated because the overhead view shows an area relatively close to the vehicle while the vehicle is moving at high speed.

  The present invention solves the above-described problem, and provides a map display device that can display a bird's-eye view corresponding to a situation in which a user is placed and a user's request, as well as corresponding to a traveling state of a vehicle.

  The vehicle guidance device of the present invention is a vehicle guidance device that draws an overhead view using map data including position information on roads, facilities, and the like, and displays the overhead view on a display unit. A plurality of different rectangular portions are configured to be arranged one above the other so as to indicate the ground continuously.

  In the vehicle guidance device of the present invention, the depression angle of each of the plurality of rectangular portions increases from the bottom to the top, or decreases from the bottom to the top. In the vehicle guidance device of the present invention, the lowest rectangular portion is made larger than the other rectangular portions.

  A vehicle guidance device according to the present invention includes a position determination unit that obtains a current position of a vehicle, a recording unit that records map data including position information regarding roads, facilities, and the like, and a part of the map data that is read to display an overhead view A control unit for converting to a map, a drawing unit for creating a bird's-eye view image data using a part of the converted map data, and displaying the bird's-eye view based on the image data together with the current position of the vehicle In a vehicle guidance device including a display unit, when the field of view overlooking the ground is divided into a plurality of rectangular parts arranged vertically, the control unit is set for each rectangular part with respect to the rectangular part. A part of the map data corresponding to an area on the ground viewed from a small depression is read from the recording unit and converted.

  The vehicle guidance device according to the present invention displays a plurality of overhead views with different depression angles arranged vertically so as to continuously indicate the ground, thereby responding to the traveling state of the vehicle and responding to the user's request. It is possible to display an overhead view. For example, when you are traveling on a road in an urban area at a low speed and you want to grasp a relatively distant point with an overhead view, the display area of the overhead view is divided into a lower rectangular part and an upper rectangular part. Separately, by making the depression angle of the upper rectangular part smaller than the depression angle of the lower rectangular part, the lower rectangular part displays a detailed information on the vicinity of the vehicle position, and indicates a relatively far point An overhead view is displayed in the upper rectangular part. In addition, when driving on a highway, if you want to increase the scale of the distant area displayed in the overhead view, make the depression angle of the upper rectangular part larger than the depression angle of the lower rectangular part. A small bird's-eye view of the far region is displayed in the upper rectangular portion without frequently updating.

  Hereinafter, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an outline of a car navigation apparatus according to an embodiment of the present invention. A CPU (Central Processing Unit) (1) constitutes a control unit of the car navigation device, and executes various controls and processes related to the car navigation device. A ROM (Read Only Memory) (3) describes the control and processing procedures, and stores a program executed by the CPU (1). The ROM (3) also stores font data relating to characters and symbols, various icon data used for drawing maps, and the like. The RAM (5) is used as a work area for the CPU (1).

  A GPS receiver (7), which is a vehicle position determination unit, determines the current position of the vehicle on which the car navigation device is mounted, using a GPS signal received via an antenna (not shown). The sensor unit (9) includes a vehicle speed sensor that detects the speed of the vehicle, a gyro sensor that detects the direction of the vehicle, and the like. The traffic information receiving unit (11) includes a receiver and a decoder used to obtain road traffic information from a traffic information system such as VICS (Vehicle Information and Communication System).

  The recording unit (13) includes a recording medium such as a DVD (Digital Versatile Disc) and a hard disk, and a drive device that reads desired data from the recording medium. The recording medium stores map data used for drawing a map, a program describing a guidance operation described later, and the like. The map data includes road data, facility data, background data, and the like, and is unitized within a predetermined geographical range and recorded in the recording unit (13).

  The road data includes information about links defined for each road section and nodes corresponding to road intersections and boundary points (points on the boundaries that define the geographical range). . Information related to each link includes an ID number, road attributes (for example, general road) and name (for example, National Route 1), road width, ID number of the node that is the end of the link, and other information connected to the link. The ID number of the link is included. The information regarding each node includes an ID number, coordinate values, node attributes (for example, intersections), names, and the like. The facility data includes the coordinates of the facility area, the type and name of the facility, polygon data for displaying the facility in three dimensions, and the background data includes the coordinates of the element points that specify the background type and the shape of the background. And elevation etc.

  The display unit (15) is a display device using a liquid crystal display device or an EL element, and displays a guidance map, various setting screens, and the like. The audio output unit (17) includes a speaker, an amplifier, a D / A converter, and the like. During the guidance operation, the CPU (1) appropriately generates guidance voice data based on the current position of the vehicle, and the generated voice data is reproduced by the voice output unit (17). The operation unit (19) includes a touch panel, various hard keys, a remote controller, and the like provided on the display area of the display unit (15).

  An IC (Integrated Circuit) equipped with a graphics engine for two-dimensional and three-dimensional drawing is used for the drawing unit (21). When an instruction is sent from the CPU (1), the drawing unit (21) Then, image data of various maps is created using the map data read from the recording unit (13). The image data created by the drawing unit (21) is stored in the VRAM (23), and the display unit (15) displays a map based on the image data stored in the VRAM (23). In the car navigation device of this embodiment, a two-dimensional plane map, a two-dimensional overhead view, a three-dimensional overhead view in which facilities, backgrounds, and the like are displayed in polygons can be drawn.

  FIG. 2 is a flowchart showing the guidance operation of the car navigation device of this embodiment. When the start of the guidance operation is instructed via the operation unit (19), a setting screen is displayed on the display unit (15), and the user is prompted to input a destination (S1). In step S1, in addition to the destination, one or a plurality of waypoints can be input. When the input of the destination is completed, the CPU (1) executes a route search process for determining a guidance route from the departure point to the destination (S3). In step S3, the current position of the vehicle determined by the GPS receiver (7) is set as the departure place, and the route search process is executed using, for example, the Dijkstra method or its improved method. In step S1, when a waypoint is input, a guidance route is determined so as to reach the destination through the waypoint. The determined guidance route is expressed as, for example, a link string and stored in the RAM (5).

  After step S3, a setting screen is displayed on the display unit (15), and an input regarding selection of a display mode of a map for guidance displayed along the guidance route and setting in each display mode is given to the user. You are prompted (S5). The map display mode in the car navigation device of this embodiment includes a planar map display mode, a first overhead view display mode, and a second overhead view display mode. In step S5, a display mode is selected from these. The The planar map display mode is a mode for displaying a planar map, the first overhead view display mode is a mode for displaying an overhead view in the same manner as the conventional one, and the second overhead view display mode is as described later. It is a display mode which displays a bird's-eye view in the form characterized by the present invention. Furthermore, in step S5, the presence or absence of polygon display such as facilities and backgrounds in the first or second overhead view display mode, various parameters used in the first or second overhead view display mode (for example, height H described later) , Distance L, width W1, etc.) can be set by the user.

  After the display mode is selected and set in step S5, the GPS receiver (7) determines the current position of the vehicle (S7). Then, the CPU (1) determines whether or not map drawing is necessary based on the current position (S9). For example, when the travel distance of the vehicle from the position when the map was drawn last time to the current position (latest determined in step S7) exceeds a predetermined value, or in the currently displayed map, in step S7 When the obtained current position of the vehicle is arranged in a predetermined area (for example, the upper half of the map), it is determined that the map needs to be drawn. Even when step S9 is performed for the first time, it is determined that drawing of the map is necessary. If it is determined in step S9 that map drawing is necessary, map drawing processing described later is executed (S11). After step S11, step S7 and subsequent processing are executed again.

  If it is determined in step S9 that the drawing of the map is unnecessary, it is determined whether or not the guidance operation is to be terminated (S13). For example, when it is determined from the current position obtained in step S7 that the vehicle has reached the current destination, or when an end is instructed via the operation unit (19), the guidance operation is ended. . If it is determined in step S13 that the guidance operation is not terminated, a process of updating the position of an icon (for example, see FIG. 4B) indicating the vehicle position displayed together with the map is performed (S15). After step S15, step S7 and subsequent processing are performed again.

  FIG. 3 is a flowchart showing details of the map drawing process in step S11 shown in FIG. First, it is determined whether or not the planar map display mode is selected (S31). When the planar map display mode is selected, after step S31, map data in a predetermined range including the current position of the vehicle is read from the recording unit (13) and stored in the RAM (5) (S33). ). The drawing unit (21) draws a planar map using the map data read in step S33, icon data indicating facilities (stored in the ROM (3)), etc. Data is created (S35). The image data created in step S35 is stored in the VRAM (23) after being combined with data indicating an icon indicating the vehicle position (S37). Then, the display unit (15) performs a process of displaying a map based on the image data stored in the VRAM (23) (S39).

  If it is determined in step S31 that the planar map display mode is not selected, an overhead view is drawn, so that the viewpoint S and the angle φ of the overhead view are determined (S41). The ROM (3) stores a table in which numerical values that give the viewpoint S according to the running state of the vehicle are stored. In step S41, the CPU (1) determines the table based on the running state of the vehicle. To determine the viewpoint S (the values of the X, Y and Z coordinates of the viewpoint S are determined).

  FIG. 4A is an explanatory diagram illustrating a method for creating an overhead view in the first overhead view display mode. The ground, that is, the plane described by the map data is on the XY plane. The intersection point O is an intersection point between the perpendicular line drawn from the viewpoint S to the XY plane and the XY plane. The viewpoint S is, for example, from the intersection point O, the direction of viewing the current position P of the vehicle from the intersection point O. It is determined so as to coincide with the direction of viewing the destination (or waypoint) or along the direction of the vehicle detected by the sensor unit (9). The table stored in the ROM (3) includes, for example, the height H of the viewpoint S, the intersection point O, and the vehicle for each of the case where the vehicle is traveling on a highway and the case where the vehicle is traveling on a general road. The distance L between the current position P and the depression angle φ is described. The height H when the vehicle is traveling on an expressway is smaller than the height H when traveling on an ordinary road, and the distance L when traveling on an expressway is traveling on an ordinary road. The distance L is larger than the distance L. Further, the depression angle φ when traveling on a highway is made smaller than the depression angle φ when traveling on a general road. In FIG. 4A (and similar figures to be referred to hereinafter), for the sake of simplicity, a coordinate system in which the intersection point O is the origin and the current position P of the vehicle is on the Y axis is employed.

  When the viewpoint S is determined in step S41, it is determined whether or not the first overhead view display mode is selected (S43). When the first bird's eye view display mode is selected, map data in a range necessary for drawing the bird's eye view is read from the recording unit (13) and stored in the RAM (5) (S45). Referring to FIG. 4A, the region on the XY plane to be drawn is a trapezoidal region ABCD in which a quadrangular pyramid having the viewpoint S as a vertex intersects the XY plane. In step S45, map data relating to the range including the trapezoidal area ABCD is read from the recording unit (13).

  After step S45, an overhead view is drawn using the map data read out and stored in the RAM (5), the icon data stored in the ROM (3), and the like (S47). FIG. 5 is an explanatory diagram showing a visual field to be seen from above. The horizontal spread angle π and the vertical spread angle η that define a rectangular field of view overlooking the XY plane are similar to the view area of the overhead view in the display unit (15). Is predetermined. The angle formed by the straight line passing through the viewpoint S and the center of the rectangle abcd that is a cross section of the quadrangular pyramid having the vertex S and the XY plane is the depression angle φ. The overhead view drawn by the drawing unit (21) is a mapping obtained by projecting the area in the trapezoidal area ABCD onto a rectangle abcd that gives a field of view (for example, the point A is a straight line passing through the viewpoint S and the point a and X− This is the intersection with the Y plane). In step S47, the CPU (1) converts the coordinate values included in the read map data (to the coordinate values on the rectangle abcd) and displays overhead view data (hereinafter referred to as "overhead view data"). ) Is created. Then, according to an instruction from the CPU (1), the drawing unit (21) draws an overhead view using the created overhead view data. When the facility or background polygon is displayed, the facility polygon data and background elevation information are referred to draw a three-dimensional overhead view.

  After step S47, step S37 is executed, and the drawing unit (21) adds image data indicating an empty area, icon data indicating the vehicle position, etc. to the image data of the overhead view created in step S45. The image data for display is created by combining and stored in the VRAM (23). Thereafter, step S39 is executed, and a guidance map is displayed on the display unit based on the image data stored in the VRAM (23).

  FIG. 4B is an explanatory diagram showing an image displayed on the display unit (15) when step S39 is executed in the first overhead view display mode. The upper part of the image is an empty area (31), and its width W1 (for example, specified by the number of pixels in the vertical direction) is predetermined. The overhead view (32) is displayed below the sky region (31), and an icon (33) indicating the vehicle position P is displayed in the overhead view (32). Although not shown in the overhead view (32), in addition to the icon (33), road shape, road sign, road information, VICS information, intersection information, facility shape, facility shape, facility icon, place name, via An icon or the like indicating the place or the destination is drawn (the same applies to FIG. 6B shown later). In FIG. 4B (and other similar figures), vertical grid lines (34) and horizontal grid lines (35) which are mappings of lines arranged in a grid pattern at equal intervals on a plane described by map data are shown. ) Are shown, but these may not be displayed on the display unit (15).

  If it is determined in step S43 that the first overhead view display mode is not selected, processing for drawing the overhead view in the second overhead view display mode is performed. In the second bird's-eye view display mode, the displayed bird's-eye view is composed of a region overlooking the ground at the depression angle φ determined in step S41 and one or a plurality of regions overlooking the ground at angles different from the depression angle φ. (Hereinafter, these areas are referred to as “divided areas”). The shape of each divided area is rectangular and arranged vertically. These divided areas indicate the ground continuously as a whole, and a certain divided area is geographically connected to the divided area below it, and the angle of depression of these divided areas increases from the bottom to the top or It is preferable to be small. In addition, the width (size) of the lowermost divided area is preferably made the largest compared to other divided areas, and more preferably occupies half or more of the whole overhead view. For example, the image displayed in the second overhead view display mode is an overhead view (32) shown in FIG. 4B in which the upper rectangular portion (divided region) having the width W2 is seen from above the ground at a depression angle different from the depression angle φ. Changed to an overhead view. Note that the width W2 is made smaller than the width W3 of the lower rectangular portion overlooking the ground at the depression angle φ.

  When it is determined in step S43 that the first bird's eye view display mode is not selected, the CPU (1) determines a numerical value (for example, width W2 or W3) for specifying the divided area and the divided area of the depression angle φ. A change in depression angle (or depression angle) in each of the divided areas excluding is determined (S49). For example, the ROM (3) stores a table referred to in step S49, and the table includes a case where the vehicle is traveling on a highway and a case where the vehicle is traveling on a general road. A numerical value specifying the divided area and a change in depression angle in each divided area excluding the divided area of depression angle φ are described. These values may be freely set by the user in step S5, for example, and a predetermined operation is performed via the operation unit (19) during the guiding operation shown in FIGS. Then, a setting screen is displayed in the interrupt process, and these values may be set or changed (and the display mode may be set or changed).

  As an example, let us consider a case where the rectangular upper divided area having the width W2 shown in FIG. 4B and the depression angle change θ in the divided area are specified in step S49. In FIG. 4B and FIG. 5, the upper divided area and the corresponding field of view are indicated by a rectangle efcd, and the lower divided area and the corresponding field of view are indicated by a rectangle abfe. Point E is an intersection of a straight line connecting viewpoint S and point e and the XY plane, and point F is an intersection of a straight line connecting viewpoint S and point f and the XY plane. .

  6A is an explanatory diagram showing a method of creating an overhead view in which the depression angle is larger by the angle θ than the depression angle φ for the upper divided region shown in FIG. 4B. For the lower divided area, the map data is converted so that the trapezoidal area ABFE is mapped to the rectangle abfe in the same manner as described above, and overhead view data is created. The overhead view of the upper divided area shows a trapezoidal area EFC′D ′ as a rectangle efcd in a state where the plane described by the map data is rotated counterclockwise by an angle θ (in the figure) about the straight line EF. To be understood as a mapping. The trapezoidal region EFC′D ′ is a region where a quadrangular pyramid having the viewpoint S as a vertex and the rectangle efcd as a cross section intersects the rotated plane. FIG. 7A is an explanatory diagram showing a method of creating an overhead view in which the depression angle is smaller than the depression angle φ by the angle θ for the upper divided region shown in FIG. 4B. For the upper divided region, the trapezoidal region EFC ″ D ″ is changed to a rectangle efcd in a state where the plane described by the map data is rotated clockwise by the angle θ (in the drawing) about the straight line EF. It is understood as a mapping. The trapezoidal region EFC ″ D ″ is a region where a quadrangular pyramid having the viewpoint S as a vertex and a rectangle efcd as a cross section intersects the rotated plane.

  8A to 8C are explanatory views corresponding to FIGS. 4A, 6A, and 7A, respectively, as viewed from the X-axis direction. FIG. 8B also shows a coordinate system rotated counterclockwise by an angle θ about the straight line EF, and FIG. 8C also shows a coordinate system rotated clockwise by an angle θ about the straight line EF. (The viewpoint S is fixed in the space, and the intersection point O defined as described above moves on the XY plane). Referring to FIG. 8B, it is understood that the overhead view of the upper divided area is a map that is projected onto the rectangle efcd when the XY plane is viewed from the viewpoint S at the depression angle φ + θ in the visual field shown in FIG. Note that the height H and the distance L that define the viewpoint S in FIG. 8B are different from the values in FIG. 8A. The height H and the distance L in FIG. 8B are determined by rotating a quadrangular pyramid having the viewpoint S as a vertex from the state shown in FIG. 8A so as to give a depression angle φ + θ with the straight line EF as an axis. Referring to FIG. 8C, it is understood that the overhead view of the upper divided region is a map that is reflected in the rectangle efcd when the XY plane is viewed from the viewpoint S at the depression angle φ-θ in the visual field shown in FIG. Is done. The height H and the distance L of the viewpoint S in FIG. 8C are determined by rotating a quadrangular pyramid having the viewpoint S as a vertex from the state shown in FIG. 8A so as to give a depression angle φ−θ about the straight line EF. The

  Referring to FIG. 3 again, based on the information confirmed in step S49, a part of the map data including the geographical area corresponding to the first divided area (for example, the area viewed from the depression angle φ) is read out. After (S51), an overhead view is drawn in the same manner as in step S47, and the image data is created (S53). For example, in the example shown in FIGS. 6A and 7A, map data is read for a geographical area including the trapezoidal area ABFE in step S51 and displayed in a lower divided area in step S53 (rectangular). An overhead view of the depression angle φ (which is a mapping of the trapezoidal area ABFE to abfe) is drawn.

  After step S53, it is determined whether or not the overhead view drawing has been completed for all the divided regions (S55). If there is a divided area where drawing is not performed, steps S51 and S53 are executed again. In the example shown in FIG. 6A, map data is read for a geographical range including the trapezoidal region EFC'D 'in step S51 performed again, and this map data is used in step S53 performed again. Then, an overhead view of the depression angle φ + θ (which is a mapping to the rectangle efcd) displayed in the upper divided area is drawn. In the example shown in FIG. 7A, the map data is read for the geographical range including the trapezoidal region EFC ″ D ″ in step S51 performed again, and is read in step S53 performed again. Using the map data, an overhead view of the depression angle φ−θ (mapped to the rectangle efcd) displayed in the upper divided area is drawn.

  When the drawing of the bird's-eye view is completed for all the divided areas, step S37 is executed, and the drawing unit (21) displays a plurality of image data created by repeating step S53 and an image showing the empty area (31). The data and the data of the icon (33) indicating the vehicle position are combined to create display image data, which is stored in the VRAM (23). Then, step S39 is performed and the map for guidance in the second overhead view display mode is displayed on the display unit.

  FIG. 6B is an explanatory diagram illustrating an image displayed on the display unit 15 in the case illustrated in FIG. 6A. In the lower divided area, an overhead view is displayed at the same depression angle φ as in FIG. 4B, but in the upper divided area, an overhead view is displayed at an elevation angle φ + θ larger than that of the lower divided area. The geographical area shown in the upper divided area is narrower than that of FIG. 4B, but the scale is increased. The vertical grid line (34) is bent so that the interval is widened in the upper divided region with the line segment ef as a boundary, and the interval of the horizontal grid line (35) in the upper divided region is compared with FIG. 4B. And become wider.

  FIG. 7B is an explanatory diagram showing an image displayed on the display unit (15) in the case shown in FIG. 7A. In the lower divided area, an overhead view is displayed at the same depression angle φ as in FIG. 4B, but in the upper divided area, an overhead view is displayed at an angle φ−θ smaller than that of the lower divided area. The geographical area shown in the upper divided area is wider than that in FIG. 4B, and the scale of the upper divided area is smaller than that in FIG. 4B. The vertical grid line (34) is bent so that the interval is narrowed in the upper divided region with the line segment ef as a boundary, and the interval of the horizontal grid line (35) in the upper divided region is compared with FIG. 4B. And become narrower.

  In the example shown in FIG. 6B and FIG. 7B, the display area of the overhead view is divided into two and the depression angle of these two divided areas is changed. As described above, the flowchart of FIG. However, as is apparent, in the present invention, the number of divided areas is not basically limited (in practice, it will be limited by the size of the screen of the display unit (15), the resolution, etc.). FIG. 9A is an explanatory diagram illustrating a drawing method when the display area of the overhead view is divided into three divided areas having different depression angles. FIG. 9B is an explanatory diagram showing an image displayed on the display unit (15) in this case. In FIG. 9B, the overhead view display area is divided into a first divided area having a width W4, a second divided area having a width W3, and a third divided area having a width W2. An overhead view of depression angle φ is shown in the first divided area, an overhead view of depression angle φ + θ1 is shown in the second divided area, and an overhead view of depression angle φ + θ2 is shown in the third divided area. Note that θ2 is larger than θ1. FIG. 10 is an explanatory diagram showing a visual field. The rectangle abfe corresponds to the first divided region, the rectangle eff′e ′ corresponds to the second divided region, and the rectangle e′f′cd corresponds to the third divided region.

  The overhead view of the first divided area is created as described above. On the plane described by the map data, the points E ′ and F ′ that define the trapezoidal region EFF′E ′ corresponding to the second divided region are determined as follows. Point E ′ is the intersection of the rotated plane and the straight line connecting viewpoint S and point e ′ by rotating the plane described by the map data counterclockwise by angle θ1 about straight line EF. . Point F ′ is the intersection of the straight line connecting viewpoint S and point f ′ and the rotated plane. The overhead view of the second divided area is a mapping of the trapezoidal area EFF'E 'to the rectangle eff'e' in a state where the plane described by the map data is rotated counterclockwise by the angle θ1 about the straight line EF. As understood.

  Points C ″ and D ″ that define the trapezoidal region E′F′C ″ D ″ corresponding to the third divided region are determined as follows. The plane described by the map data is rotated counterclockwise by the angle θ1 about the straight line EF, and then further rotated counterclockwise by the angle θ2-θ1 about the straight line E′F ′. The intersection of the straight line connecting the viewpoint S and the point c and the rotated plane becomes the point C ″. Further, the intersection of the straight line connecting the viewpoint S and the point d and the rotated plane becomes the point D ″. The overhead view of the third divided area is obtained by rotating the plane described by the map data counterclockwise by the angle θ1 about the straight line EF, and further rotating the angle θ2-θ1 counterclockwise about the straight line E′F ′. It can be understood as a mapping of the trapezoidal region E′F′C ″ D ″ to the rectangle e′f′cd in a state of being rotated only by the angle.

  FIG. 11 is an explanatory diagram corresponding to FIG. 9A, and shows the situation shown in FIG. 9A viewed from the X-axis direction. FIG. 11 shows a coordinate system rotated counterclockwise by an angle θ1 about the straight line EF and a coordinate system further rotated counterclockwise by an angle θ2-θ1 about the straight line E′F ′. (The viewpoint S is fixed in space, and the intersection point O moves on the XY plane). Referring to FIG. 11, it is understood that the overhead view of the second divided region is a map that is reflected in the rectangle eff′e ′ when the XY plane is viewed from the viewpoint S at the depression angle φ + θ1 in the visual field shown in FIG. 5. Is done. Note that the viewpoint S in this case is determined by rotating a quadrangular pyramid having the viewpoint S as a vertex from the state shown in FIG. 8A so as to give a depression angle φ + θ1 about the straight line EF. Further, it is understood that the overhead view of the third divided region is a map that is projected onto the rectangle e′f′cd when the XY plane is viewed from the viewpoint S at the depression angle φ + θ2 in the visual field shown in FIG. The viewpoint S in this case is determined by rotating a quadrangular pyramid having the viewpoint S as a vertex from the state shown in FIG. 8A so as to give a depression angle φ + θ2 around the straight line E′F ′.

  In the second overhead view display mode, the divided areas may be determined based on the viewpoint S or the current position P of the vehicle determined in step S41 of FIG. For example, as shown in FIG. 4A, the depression angle is changed for an area far from the current position P of the vehicle, with a straight line orthogonal to the straight line OP as a boundary, separated from the intersection O by a predetermined distance R (in the traveling direction). As described above, the second overhead view display mode may be executed. In this case, the above-mentioned points E and F are determined as the intersections of the quadrangular pyramid with the viewpoint S as the vertex and the straight line serving as the boundary. As a result, the points e and f, and the above-described upper and lower divided areas are determined.

  The operation unit (19) is provided with a scroll key (not shown) for scrolling the map displayed on the display unit (15). When the map is displayed on the display unit (15) in the planar map display mode and the first and second overhead view display modes, if the scroll key is operated, the interrupt process is executed and the area indicated by the map moves. To do. For example, when the scroll key is operated in the second bird's eye view display mode, a process of moving the viewpoint S in a plane perpendicular to the Z axis is performed according to the pressing position and the pressing time of the scroll key. For the viewpoint S, processing similar to steps S51 to S55 shown in FIG. 4 and steps S37 and S39 is performed. As a result, a plurality of divided regions having different depression angles are scrolled.

  Further, in the car navigation device of the present embodiment, when a map is displayed on the display unit (15), if a specific facility is selected on the screen via the operation unit (19), an interrupt process is performed. Once executed, a (detailed) overhead view around the facility is displayed. The bird's-eye view displayed by this processing can also be composed of a plurality of divided regions having different depression angles, like the bird's-eye view in the second bird's-eye view display mode. For example, when display of a bird's-eye view around a facility is instructed, the viewpoint S is determined in the vicinity of the facility by performing the same process as step S49 shown in FIG. It is determined). And the process similar to step S51 thru | or S55 and also step S37 and S39 is performed, and the bird's-eye view around a plant | facility is displayed on a display part (15) similarly to 2nd bird's-eye view display mode.

  Further, in the car navigation device of the present embodiment, when a predetermined operation is performed while a certain type of map is displayed on the display unit (15), an interrupt process is executed, and a plurality of displays are displayed on the display unit (15). Types of maps are displayed. For example, when a planar map is displayed on the display unit (15), if this operation is performed, a planar map is displayed on the left half of the display unit (15) and an overhead view (and sky) is displayed on the right half. The This bird's-eye view may also be composed of a plurality of divided regions with different depression angles, similar to the above-described second bird's-eye view display mode, depending on user preference. When this operation is performed when the overhead view is displayed in the second overhead view display mode on the display section (15), the left half of the display section (15) is composed of a plurality of divided areas having different depression angles. The overhead map is displayed as a plane map on the right half.

  It should be noted that the present invention can be described using mathematical expressions different from those described above. For example, in the example described together with FIGS. 6A, 6B, and 8B, the overhead view of the upper divided region is an overhead view of the trapezoidal region EFCD from the viewpoint S with the rectangle efcd as the field of view. May be understood as an angle formed by a straight line passing through the center of the rectangle efcd and the trapezoidal region EFCD. Further, the overhead view of the lower divided area is an overhead view of the trapezoidal area ABFD from the viewpoint S with the rectangle abfe as the field of view, and this depression angle is a straight line passing through the viewpoint S and the center of the rectangle abfe and the trapezoidal area It may be understood as an angle formed by ABFD.

  The above description of the embodiments is for explaining the present invention, and should not be construed as limiting the invention described in the claims or reducing the scope thereof. Moreover, each part structure of this invention is not restricted to the said Example, Of course, a various deformation | transformation is possible within the technical scope as described in a claim.

It is a block diagram which shows the outline | summary of the car navigation apparatus which is an Example of this invention. It is a flowchart which shows the guidance operation | movement of the car navigation apparatus of this invention. It is a flowchart which shows the detail of the map drawing process of the car navigation apparatus of this invention. FIG. 4A is an explanatory diagram showing a method for creating an overhead view in the first overhead view display mode of the car navigation device of the present invention, and FIG. 4B shows an image displayed on the display unit in the first overhead view display mode. It is explanatory drawing shown. It is explanatory drawing which shows the visual field which looks down at the plane described with map data in the 2nd bird's-eye view display mode of the car navigation apparatus of this invention. FIG. 6A is an explanatory diagram showing a method for creating an overhead view in the second overhead view display mode of the car navigation device of the present invention, and FIG. 6B shows an image displayed on the display unit in the second overhead view display mode. It is explanatory drawing shown. FIG. 7A is an explanatory diagram showing a method for creating an overhead view in the second overhead view display mode of the car navigation device of the present invention, and FIG. 7B shows an image displayed on the display unit in the second overhead view display mode. It is explanatory drawing shown. 8A to 8C are explanatory views showing a method for creating an overhead view in the car navigation apparatus of the present invention, and correspond to FIGS. 4A, 6A, and 7A, respectively. FIG. 9A is an explanatory diagram showing a method for creating an overhead view in the second overhead view display mode of the car navigation device of the present invention, and FIG. 9B shows an image displayed on the display unit in the second overhead view display mode. It is explanatory drawing shown. It is explanatory drawing which shows the visual field which looks down at the plane described with map data in the 2nd bird's-eye view display mode of the car navigation apparatus of this invention. It is explanatory drawing which shows the preparation method of the overhead view in the car navigation apparatus of this invention, and respond | corresponds to FIG. 9A.

Explanation of symbols

(1) CPU
(3) ROM
(5) RAM
(7) GPS receiver
(13) Recording section
(15) Display section
(21) Drawing part
(31) Empty area
(32) Overhead view area
(33) Icon

Claims (5)

In a vehicle guidance device that draws an overhead view using map data including position information on roads, facilities, etc., and displays the overhead view on a display unit,
The overhead view is a vehicle guidance device characterized in that a plurality of rectangular portions with different depression angles are arranged vertically so as to continuously show the ground.   The vehicle guidance device according to claim 1, wherein a depression angle of each of the plurality of rectangular portions increases from the bottom to the top.   2. The vehicle guidance device according to claim 1, wherein a depression angle of each of the plurality of rectangular portions decreases from bottom to top.   The vehicle guidance device according to any one of claims 1 to 3, wherein the lowermost rectangular portion is larger than the other rectangular portions. A position determining unit for obtaining a current position of the vehicle, a recording unit for recording map data including position information on roads and facilities, a control unit for reading out a part of the map data and converting it for an overhead view display, and conversion A vehicle comprising: a drawing unit that creates a bird's-eye view image data using a part of the map data that has been displayed; and a display unit that displays the bird's-eye view based on the image data together with the current position of the vehicle In the guidance device,
When the field of view overlooking the ground is divided into a plurality of rectangular parts arranged vertically, the control unit corresponds to the area of the ground overlooked at a depression angle set with respect to each rectangular part. A part of the map data is read from the recording unit and converted.

Images