JP2010049244A - Drawing-processing device, drawing-processing method, and drawing-processing program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve such a problem that roads, which originally do not cross, occasionally cross when a bird's-eye view is drawn by a bird's-eye view conversion. <P>SOLUTION: Map information M includes information on lines interpolated by a plurality of interpolation points. A reversal bird's-eye view conversion part 68 subjects the frame of a screen, which displays a bird's-eye view obtained when one looks down at a two-dimensional map from a prescribed viewpoint position, to a reversal bird's-eye view conversion to obtain a rectangular area on the two-dimensional map to be displayed as the bird's-eye view. An interpolation point-adding part 70 adds a point which exists on the sides of the rectangular area thus found or inside this rectangular area and is located between existing interpolation points adjacent to each other and interpolates a line, as the new interpolation point of the line. A bird's-eye view conversion part 62 subjects interpolation points for interpolating a line including the added interpolation point to the bird's-eye view conversion to generate the bird's-eye view obtained when one looks down at the two-dimensional map from the viewpoint position. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a drawing processing device, a drawing processing method, and a drawing processing program for drawing map information.

  A navigation device, which is an example of a drawing processing device that displays a map, is used in various fields, and is mainly mounted on a vehicle or the like and used to guide a route from a current location to a destination. The navigation device is equipped with a heading-up mode and a north-up mode that display a two-dimensional map with the line of sight looking down from directly above the vehicle position, as well as a direction of movement from behind the traveling direction above the vehicle position. It also has a three-dimensional mode that displays a bird's eye view looking down.

  With respect to a bird's eye view, a navigation device that calculates a trapezoidal road map area corresponding to a display screen area, selects an interpolation point in the road map area from map information, and performs projective conversion is generally known (for example, Patent Document 1). In order to speed up the creation of a bird's-eye view, a navigation device has also been proposed that displays a bird's-eye view by thinning out road interpolation points according to the screen display position and display priority (for example, see Patent Document 2).

JP-A-8-160852 JP-A-8-159783

  However, in the general bird's-eye view generation technology described in Patent Document 1 and Patent Document 2, projective transformation is performed on a plurality of continuous interpolation points representing a road, the interpolation points are adjusted, and the interpolation points and the interpolation points are changed. When a road is drawn with a connecting line, two roads that do not originally intersect may intersect due to the difference in accuracy of interpolation points for interpolating the road.

  The interpolation point of the road in the map information is composed of two-dimensional latitude / longitude coordinates viewed from directly above. For this reason, the coordinates of the interpolation point of the two-dimensional map that is distant from the center position of the bird's eye view greatly move when the bird's eye view is converted. If the map information stores interpolation points at intervals of 1 meter for all roads, all the interpolation points are converted to a bird's eye view and the road is drawn, and the techniques described in Patent Document 1 and Patent Document 2 are accurate. A bird's-eye view can be displayed. However, actual map information includes roads composed of interpolation points at intervals of 1 meter, and roads composed of interpolation points at intervals of 100 meters. In particular, when two roads having different distance intervals between successive interpolation points representing roads are close to each other and exist in parallel, a bird's-eye view is obtained with respect to all the interpolation points of the road in order to obtain a bird's-eye view. If you convert and connect the calculated points with a line, they may intersect unintentionally.

  The present invention has been made in view of such a situation, and an object thereof is to create a bird's-eye view having an accurate positional relationship from two-dimensional map information.

  In order to solve the above-described problem, a drawing processing apparatus according to an aspect of the present invention includes a map information storage unit that stores map information including information on a plurality of interpolation points for forming a line, and drawing based on the map information. By performing reverse conversion processing opposite to the interpolation point conversion processing for bird's-eye view generation on the display frame of the screen displaying the bird's-eye view when assuming that the two-dimensional map to be viewed is looked down from the predetermined viewpoint position An inverse transform processing unit for obtaining a rectangular area on a two-dimensional map displayed as a bird's eye view, and a line existing between adjacent interpolation points existing on or in the side of the rectangular area An interpolating point adding unit that adds a point as a new interpolating point of the line, and the interpolating point for forming a line including the added interpolating point, by performing the conversion processing, generates the bird's eye view And a bird's eye view generating unit.

  Another aspect of the present invention is a drawing processing method. In this method, it is assumed that a map information including information on a plurality of interpolation points for forming a line is referred from a memory, and that a two-dimensional map drawn based on the map information is looked down from a predetermined viewpoint position. A step of obtaining a rectangular area on a two-dimensional map displayed as a bird's-eye view by performing reverse conversion processing opposite to the interpolation point conversion processing for bird's-eye view generation on the display frame of the screen displaying the bird's-eye view Adding a point that is on or in the side of the rectangular area and is between existing adjacent interpolation points to form a line as a new interpolation point of the line, and the added interpolation Generating the bird's-eye view by performing the conversion process on interpolation points for forming lines including points.

  It should be noted that any combination of the above-described constituent elements and a conversion of the expression of the present invention between a method, an apparatus, a system, a recording medium, a computer program, etc. are also effective as an aspect of the present invention.

  According to the present invention, it is possible to create a bird's eye view having an accurate positional relationship based on two-dimensional map information.

It is a block diagram which shows roughly the function of the navigation apparatus which concerns on embodiment of this invention. It is a block diagram of the arithmetic unit of FIG. It is a figure explaining the two-dimensional window coordinate system in the case of displaying a two-dimensional map on a screen. It is a figure which shows the example of the two-dimensional map displayed by the interpolation point of a two-dimensional window coordinate system. It is a figure explaining the three-dimensional window coordinate system in the case of displaying a bird's-eye view on a screen. It is a figure which shows the example of the bird's-eye view displayed by the interpolation point of a three-dimensional window coordinate system. It is a figure explaining the interpolation point of the two-dimensional window coordinate system for drawing the two-dimensional map of FIG. It is a figure explaining the bird's-eye view drawn by performing bird's-eye view conversion of the interpolation point of the two-dimensional window coordinate system shown in FIG. It is the figure which reversely converted the bird's-eye view map and displayed it in the two-dimensional map on the screen on which the bird's-eye view is displayed. It is a figure which shows the bird's-eye view drawn by carrying out bird's-eye view conversion using the newly added interpolation point. It is a flowchart explaining the bird's-eye view production | generation method which concerns on this Embodiment. It is the bird's-eye view which showed two roads and the interpolation point in the three-dimensional window coordinate system. FIG. 13 is a diagram in which a display frame of the screen of FIG. 12 on which a bird's eye view is displayed is converted into a reverse bird's eye view and displayed in a two-dimensional map. It is a figure which shows the bird's-eye view drawn by carrying out bird's-eye view conversion using the newly added interpolation point. It is the bird's-eye view which showed two roads and the interpolation point in the three-dimensional window coordinate system. FIG. 16 is a diagram in which a display frame of the screen of FIG. 15 on which a bird's eye view is displayed is converted into a reverse bird's eye view and displayed in a two-dimensional map. It is a figure which shows the bird's-eye view drawn by carrying out bird's-eye view conversion using the newly added interpolation point.

  FIG. 1 is a block diagram schematically showing functions of the navigation device 1 according to the embodiment of the present invention.

  The navigation device 1 is a position detection device 2 that detects the current location of a driver who is a user, a road map that connects interpolation points and interpolation points with lines, road regulations, background information, icons, information necessary for map display such as map information M An information storage unit 3 that stores information, a user interface unit 4 that functions as an interface with a driver, an information processing unit 5 that performs various conversion processes of information such as map information M, and the like. Such a navigation device 1 is used by being mounted on a vehicle or the like that is driven by a driver, and guides the driver the optimum route from the departure point to the destination.

  The position detection device 2 includes a GPS sensor 21 that receives GPS signals from GPS (Global Positioning System) satellites, a gyro sensor 22, a road information reception sensor 23 that receives road traffic information from beacons, FM multiplex broadcasts, and the like, and a speed. A sensor 24 and the like are provided. Such a position detection device 2 receives external radio waves and information and transmits the radio waves and information to the information processing unit 5.

  The information storage unit 3 stores various types of information required by the information processing unit 5 including the map information M, and transmits and receives various types of information to and from the information processing unit 5.

  The user interface unit 4 includes a voice input / output device 41 for performing voice input and voice output, a display 42 such as an LCD (liquid crystal display) for displaying various screens, a control device 43 for receiving operations from a driver, and the like. ing. Such a user interface unit 4 transmits and receives audio information, image information, and the like to and from the information processing unit 5. The voice input / output device 41 provides voice guidance for the route searched by the information processing unit 5. Further, since the voice input / output device 41 has a voice input function, it receives an instruction from the driver by voice. Here, the voice input / output device 41 and the control device 43 function as an input unit, and the display 42 functions as a display unit.

  The information processing unit 5 includes an arithmetic device 51 that performs various arithmetic operations, a sensor interface 52, a communication interface 53, an image sound processing device 54, and the like.

  The arithmetic unit 51 includes a central processing unit (CPU) that centrally controls each unit, a read only memory (ROM) that stores various programs executed by the CPU, a random access memory (RAM) that functions as a work area of the CPU, and the like. , A timer, an image memory, and the like (all not shown), and execute various arithmetic processes. For example, the arithmetic device 51 performs processing such as an affine transformation unit, a bird's eye view conversion unit, a reverse bird's eye view conversion unit, and an interpolation point addition unit, which will be described later.

  The sensor interface 52 receives the position information detected by each of the sensors 21, 22, 23, and 24 of the position detection device 2 and transmits the position information to the arithmetic device 51. Further, the computing device 51 obtains road information such as current location information, traffic jam information, and accident information based on the position information, and further obtains optimum route information and different route information based on the current location information and destination information. Ask.

  The destination information is set by the driver's operation on the control device 43 or the driver's instruction by voice to the voice input / output device 41. That is, the arithmetic device 51 sets a destination in accordance with a driver operation on the control device 43 and a driver instruction by voice to the voice input / output device 41.

  The communication interface 53 acquires the map information M from the information storage unit 3 and transmits it to the arithmetic device 51. The communication interface 53 receives a signal from the control device 43 of the user interface unit 4.

  The audio / video processing device 54 transmits audio information and image information to the audio input / output device 41 and the display 42 of the user interface unit 4 and receives audio information from the outside (for example, a driver).

  FIG. 2 is a configuration diagram of the arithmetic device 51. Here, a function for generating a bird's-eye view among the functions of the arithmetic device 51 is illustrated.

  The map information M includes node information such as roads, rivers, and railways, and each node information has a plurality of interpolation points. For example, in the case of a road, an interpolation point is composed of two-dimensional coordinates of latitude and longitude and road attributes such as the number of lanes. The road width is determined by the number of lanes. In this specification, nodes such as roads, rivers, and railroads that are interpolated with interpolation points are collectively referred to as “lines”, and information including interpolation points and line attributes for interpolating lines is referred to as “lines”. It is called “information”. “Line” has a thickness corresponding to the attribute of the line.

  Since the affine transformation unit 60 draws a two-dimensional map on the screen of the display 42 based on the line information included in the map information M stored in the information storage unit 3, the affine transformation unit 60 is expressed by the latitude and longitude of the interpolation point of the line. The general coordinates are affine transformed into a two-dimensional window coordinate system corresponding to the screen of the display 42 in accordance with the scale and the rotation angle. Information on the interpolation point 72 in the two-dimensional window coordinate system after the affine transformation is stored in the memory.

  The reverse bird's-eye view conversion unit 68 projects the area displayed on the screen as a bird's-eye view on the two-dimensional map by converting the display frame of the screen of the display 42 on which the bird's-eye view is displayed. Thereby, the trapezoid area displayed as a bird's-eye view is obtained in the two-dimensional map. More specifically, the reverse bird's-eye view conversion unit 68 performs reverse bird's-eye view conversion on the top of the display frame of the screen on which the bird's-eye view is displayed (represented by a “three-dimensional window coordinate system” described later) on the two-dimensional map. Of the trapezoidal area (represented by a “two-dimensional window coordinate system” described later).

  The interpolation point adding unit 70 adds a point for interpolating the line as a new interpolation point between the existing adjacent interpolation points of the line. This new interpolation point is provided on or inside the trapezoidal area displayed as a bird's eye view.

  In particular, when any side of a trapezoidal area displayed as a bird's-eye view intersects with a line segment formed by sequentially connecting interpolation points, the interpolation point adding unit 70 adds the intersection as a new interpolation point of the road. May be. Alternatively, the interpolation point adding unit 70 may add a new interpolation point to a section in which the interval between the interpolation points of the lines is coarser than the other inside the trapezoid area.

  The interpolation point adding unit 70 obtains the density of interpolation points for a plurality of lines existing in a trapezoidal area displayed as a bird's eye view, and preferentially adds a new interpolation point for a line having a coarse interpolation point density. May be performed. Alternatively, the process of adding a new interpolation point may be skipped for a line whose interpolation point density is higher than a predetermined threshold. Thereby, it is possible to increase the calculation efficiency by avoiding the process of adding interpolation points more than necessary.

  The interpolation point adding unit 70 updates the information of the interpolation point 72 of the two-dimensional window coordinate system stored in the memory by adding the coordinates and attributes of the new interpolation point. As a result, a line such as a road is interpolated by adding a new interpolation point in addition to the interpolation point originally present as the map information M, and the interpolation accuracy is improved.

  The bird's eye view conversion unit 62 performs projective transformation on the interpolation point 72 of the two-dimensional window coordinate system stored in the memory in order to generate a bird's eye view when the map is viewed from the predetermined viewpoint in the line-of-sight direction. Adjustments are made to obtain a sense of depth with respect to the interpolation points subjected to the projective transformation, and the bird's eye view is converted into a three-dimensional window coordinate system. Interpolation point data at the top of the screen moves from the viewpoint position at the center of the screen to the viewpoint position, and interpolation point data at the bottom of the screen moves in the direction opposite to the viewpoint position. The amount of movement increases as the interpolation point moves away from the viewpoint position, and is proportional to the vertical component from the viewpoint position with respect to the screen. Information on the interpolation point 74 in the three-dimensional window coordinate system after the bird's eye view conversion is stored in the memory.

  The line drawing unit 64 draws a line such as a road by connecting the interpolation points 74 of the three-dimensional window coordinate system stored in the memory. The thickness of the line is determined based on line attributes such as the number of road lanes.

  The display unit 66 displays a bird's-eye view image obtained by synthesizing a line such as a road drawn by the line drawing unit 64 with the background image on the display 42.

  FIG. 3 is a diagram illustrating a two-dimensional window coordinate system when a two-dimensional map is displayed on the screen.

  In heading-up mode and north-up mode, a two-dimensional map of the road viewed from directly above is displayed on the screen. Map information in which interpolation points of lines are given by latitude and longitude are represented on the XY plane, and a Z axis perpendicular to the XY plane is assumed. If the area to be displayed on the screen of the display 42 is a rectangular area ABCD (reference numeral 200) on the XY plane, the center F of the rectangular ABCD is displayed at the center of the display frame abcd (reference numeral 210) on the screen of the display 42. As described above, the viewpoint E is set right above the center F of the rectangle ABCD, and the rectangular area ABCD is affine transformed into the display frame abcd of the screen. Specifically, the rectangular area ABCD may be rotated to a display frame abcd at a scale corresponding to the viewpoint altitude after the rectangular area ABCD is rotated at a rotation angle corresponding to the traveling direction and direction of the host vehicle.

  When displaying a two-dimensional map, the display frame abcd of the screen of the display 42 is placed in parallel with the XY plane. The coordinate system of the interpolation point after the interpolation point in the rectangular area ABCD on the XY plane is converted into the display frame abcd of the screen by affine transformation is called a “two-dimensional window coordinate system”.

  FIG. 4 is a diagram illustrating an example of a two-dimensional map displayed by interpolation points in a two-dimensional window coordinate system. Here, the two roads R0, R1 and the vehicle A when viewed from directly above are displayed in two dimensions.

  The information processing unit 5 calculates the vehicle position based on the position information received by the sensor interface 52. The computing device 51 acquires interpolation points of a line such as a road in the area around the vehicle position from the map information M, and connects the interpolation points of the two-dimensional window coordinate system after the affine transformation with a line. Draw. The point (thickness) of the line is calculated by line attributes such as the scale and the number of lanes. The computing device 51 also performs affine transformation for the vehicle position, and draws the vehicle position icon A at the corresponding screen position. Here, the two roads R0 and R1 are parallel from the middle.

  FIG. 5 is a diagram illustrating a three-dimensional window coordinate system when a bird's eye view is displayed on the screen.

  Suppose that the map on the XY plane is looked down from the viewpoint E along the line of sight EF. The trapezoidal area ABCD (reference numeral 300) on the XY plane is converted into a display frame abcd (reference numeral 310) of the screen of the display 42 by bird's-eye view conversion and displayed as a bird's-eye view. In other words, the display frame abcd in which the bird's-eye view is displayed on the screen of the display 42 is converted into a trapezoid area ABCD on the two-dimensional map by reverse bird's-eye view conversion.

  When generating a bird's-eye view as viewed from the rear of the vehicle rather than from the rear of the vehicle, it should be noted that the area ABCD displayed as the bird's-eye view is not a trapezoid and is generally rectangular. In any case, the bird's-eye view is reduced as it goes farther from the vehicle and is enlarged toward the front. Therefore, the area ABCD on the two-dimensional map displayed as the bird's-eye view has a lower side on the screen. It becomes a shape with more spread.

  When displaying a bird's eye view, the display frame abcd of the screen of the display 42 is placed in the three-dimensional space XYZ. The coordinate system of the interpolation point after the interpolation point in the trapezoidal area ABCD on the XY plane is converted into the display frame abcd of the screen by bird's eye view conversion is referred to as a “three-dimensional window coordinate system”.

  FIG. 6 is a diagram showing an example of a bird's eye view displayed by interpolation points in a three-dimensional window coordinate system. Here, corresponding to the example of FIG. 4, the two roads R <b> 0 and R <b> 1 and the own vehicle A when viewed from the rear of the vehicle from the rear are displayed in three dimensions.

  The two roads R0 and R1 do not normally intersect, but if the interpolation points of the two roads are simply converted into a bird's eye view, the two roads may intersect in the bird's eye view as shown in FIG. In the present embodiment, in order not to cause such inconvenience, the reverse bird's eye view conversion unit 68 and the interpolation point addition unit 70 add the interpolation point of the road and reinforce the interpolation accuracy. Hereinafter, after explaining the cause of the inconvenience as shown in FIG. 6, the solving means according to the present embodiment will be described in detail.

  FIG. 7 is a diagram for explaining interpolation points of the two-dimensional window coordinate system for drawing the two-dimensional map of FIG. The road R0 is drawn by connecting 15 interpolation points in the two-dimensional window coordinate system in order. On the other hand, the road R1 is drawn by connecting four interpolation points H0, H1, H2, and H3 in the two-dimensional window coordinate system in order. The interval between the third interpolation point H2 and the fourth interpolation point H3 is larger than the interval between the first three adjacent interpolation points H0, H1, and H2. In addition, the number of interpolation points varies between the road R0 and the road R1, and the interpolation accuracy differs greatly.

  FIG. 8 is a diagram for explaining a bird's-eye view drawn by performing bird's-eye view conversion on the interpolation points of the two-dimensional window coordinate system shown in FIG.

  The bird's-eye view conversion unit 62 of the computing device 51 converts the interpolation point of FIG. 7 into a bird's-eye view so that the viewpoint position is in the sky behind the course of the vehicle position and the line-of-sight direction is in front of the vehicle traveling direction. The line drawing unit 64 draws a road by sequentially connecting the interpolation points of the three-dimensional window coordinate system that has been bird's-eye view converted.

  In the bird's eye view of FIG. 8, the four interpolation points H10, H11, H12, and H13 of the three-dimensional window coordinate system of the road R1 are respectively four interpolation points H0, H1, and H2 of the two-dimensional window coordinate system of FIG. , H3 is a bird's eye view converted and displayed on the screen. A road is drawn by connecting two adjacent points of the four interpolation points H10, H11, H12, and H13 in the three-dimensional window coordinate system in order.

  As can be seen from a comparison between FIG. 7 and FIG. 8, the coordinates in the X direction (lateral direction) of the fourth interpolation point H3 of the road R1 have changed greatly due to the bird's eye view conversion and moved to the center of the screen. In the three-dimensional window coordinate system, when the road R1 is drawn by connecting the third interpolation point H12 and the fourth interpolation point H13, the road R0 crosses, and an accurate bird's-eye view cannot be obtained. This is because the density of the interpolation points on the road R0 is coarse and the interpolation error increases due to the bird's eye view conversion.

  Interpolation point addition processing executed by the reverse bird's eye view conversion unit 68 and the interpolation point addition unit 70 of the computing device 51 in order to display an accurate bird's eye view will be described with reference to FIG.

  FIG. 9 is a diagram in which a display frame of a screen on which a bird's-eye view is displayed is converted into a reverse bird's-eye view and displayed in a two-dimensional map. The reverse bird's-eye view conversion unit 68 performs reverse bird's-eye view conversion on the display frame of the screen on which the bird's-eye view of FIG. 8 is displayed to obtain a trapezoidal region T in the two-dimensional map. Specifically, when XY coordinates with the position of the vehicle in the two-dimensional map as the origin are determined, the vertex of the trapezoid area T, particularly the Y coordinate value Y2 of the upper side of the trapezoid area T and the Y coordinate value Y1 of the lower side are obtained. .

  Of the four interpolation points H0, H1, H2, and H3 in the two-dimensional window coordinate system of the road R1, the first three interpolation points H0, H1, and H2 are inside the trapezoidal area T, but the fourth interpolation point H3. Is outside the trapezoidal region T. The interpolation point adding unit 70 checks whether or not a line segment formed by connecting the four interpolation points H0, H1, H2, and H3 of the road R1 in order intersects the upper side or the lower side of the trapezoidal region T. Here, a line segment connecting the third interpolation point H2 and the fourth interpolation point H3 intersects with the upper side of the trapezoidal region T at the intersection H4. This intersection H4 is added as a new interpolation point for interpolating the road R1.

  As for the interpolation point of the road R0, it may be checked whether the line segment connecting the interpolation points similarly has an intersection with the upper side or the lower side of the trapezoidal region T. However, the density of the interpolation points for the road R0 is higher than that of the road R1. Since it is high, interpolation point addition processing may be skipped for the road R0.

  Since the new interpolation point H4 of the road R1 and the interpolation point of the road R0 are located apart from each other on the upper side of the trapezoidal region T, the interpolation point is converted into a bird's-eye view for the road R1 including the new interpolation point H4. Even if it asks, two roads R1 and R0 do not cross.

  FIG. 10 is a diagram illustrating a bird's-eye view drawn by performing bird's-eye view conversion using newly added interpolation points. The two roads R0 and R1 do not intersect in the bird's eye view and are drawn accurately.

  FIG. 11 is a flowchart for explaining the bird's eye view generation method according to the present embodiment.

  The affine transformation unit 60 affine-transforms the latitude / longitude coordinates of the interpolation point representing the road to be displayed acquired from the map information M into a two-dimensional window coordinate system (step S1).

  In the example of FIG. 9, the converted interpolation points of the two-dimensional window coordinate system are 15 interpolation points of the road R0 and four interpolation points H0, H1, H2, and H3 of the road R1. At the time of affine transformation, the affine transformation unit 60 calculates the point (thickness) of the line based on the number of lanes of each road and the scale ratio of the two-dimensional map, and stores it as interpolation point information in the two-dimensional window coordinate system. (Step S2).

  Next, the reverse bird's-eye view conversion unit 68 performs reverse bird's-eye view conversion on the two-dimensional map of the rectangular area displayed on the screen as a bird's-eye view (step S3). As shown in FIG. 9, the area obtained by reverse bird's eye view conversion is a trapezoid area T, and what is specifically required is the Y coordinate Y2 of the upper side of the trapezoid area T and the Y coordinate Y1 of the lower side. Therefore, only the Y coordinates of the upper and lower sides of the rectangular area displayed on the screen as a bird's-eye view are converted by reverse bird's-eye view to calculate the Y-coordinate values Y2 and Y1 of the upper and lower sides of the trapezoid area T on the two-dimensional map.

  The interpolation point adding unit 70 forms a line by connecting two adjacent interpolation points of the road in order in the two-dimensional window coordinate system, and detects whether or not the upper side or the lower side of the trapezoidal region T intersects (step S4). Specifically, it is possible to determine whether or not it intersects with the upper side or the lower side by comparing the magnitude relationship between the Y coordinate value of the interpolation point of the road and the Y coordinate values Y2 and Y1 of the upper side and the lower side of the trapezoid region T. it can.

  In the example of FIG. 9, the line connecting the first interpolation point H0 and the second interpolation point H1 of the road R1 in the two-dimensional window coordinate system does not intersect with either the upper side or the lower side of the trapezoidal region T. The line connecting the second interpolation point H1 and the third interpolation point H2 does not intersect with either the upper side or the lower side of the trapezoidal region T. A line connecting the third interpolation point H2 and the fourth interpolation point H3 intersects the upper side of the trapezoidal region T. When the road line intersects the side of the trapezoidal region T (Y in step S4), the coordinates of the intersection and the point (thickness) of the line are calculated, and the information on the intersection is used as the third interpolation point H2 and the fourth interpolation point. A new interpolation point H4 is added during H3 (step S5). When the road line does not intersect with the side of the trapezoidal area T (N in Step S4), Step S5 is skipped and the process proceeds to Step S6.

  Similarly, for 15 interpolation points on the road R0, it is checked whether or not the line connecting adjacent interpolation points intersects with the upper side or the lower side of the trapezoidal region T, but does not intersect with the lower side of the trapezoidal region T, and the trapezoidal region T Since there is an interpolation point on or near the upper side, there is no new interpolation point to be set.

  Next, the bird's-eye view conversion unit 62 performs bird's-eye view conversion on all the interpolation points of the two-dimensional window coordinate system including the newly set interpolation point H4 (step S6). The line drawing unit 64 connects all the three-dimensional window coordinate system interpolation points calculated by bird's-eye view conversion with lines, adjusts the thickness of the lines, and draws the road (step S7). Thereby, an accurate bird's-eye view as shown in FIG. 10 can be drawn without the two roads R0 and R1 intersecting as shown in FIG.

  In the above description, when the road line intersects either the upper side or the lower side of the trapezoidal area T, the intersection point is set as a new interpolation point, thereby improving the road interpolation accuracy. Here, the upper side of the trapezoidal area T is reduced and displayed on the screen by bird's-eye view conversion, while the lower side of the trapezoidal area T is enlarged and displayed on the screen by bird's-eye view conversion. Considering this point, adding an interpolation point on the upper side of the trapezoidal region T is more important than adding an interpolation point on the lower side of the trapezoidal region T in terms of preventing an unintended intersection of the road. high. Therefore, it is possible to preferentially add the intersection point on the upper side of the trapezoidal area T displayed in a reduced scale in the bird's eye view, and not to obtain the intersection point on the lower side of the trapezoidal area T. Thereby, calculation efficiency can be improved.

  In the above description, the case where the road intersects the upper side or the lower side of the trapezoidal region T is considered, and the case where the road intersects the left side or the right side of the trapezoidal region T is not considered. This is because the display screen of the navigation device is normally horizontally long, and therefore, when a bird's-eye view is displayed, interpolation error tends to increase due to bird's-eye view conversion, particularly on the upper side of the display frame of the screen. However, if the number of interpolation points on the road is not sufficient, roads may unintentionally intersect due to interpolation errors on the left and right sides of the screen. Considering such a case, in order to further improve the accuracy of the bird's eye view, the intersection of the road and the left side or the right side of the trapezoidal area T may be obtained and added as an interpolation point. As a result, even on a road that does not intersect with the upper side or the lower side of the trapezoidal region T, interpolation accuracy can be increased by adding interpolation points when the number of interpolation points is not sufficient.

  Hereinafter, an example in which a bird's eye view is drawn by obtaining an intersection point on a side other than the upper side of the trapezoidal region and setting an interpolation point will be described.

  A case where an interpolation point is set on the lower side of the trapezoidal area will be described with reference to FIGS. FIG. 12 is a bird's eye view showing two roads R20 and R21 and their interpolation points in a three-dimensional window coordinate system. The three interpolation points J10, J11, J12 of the road R21 are in the screen, but the fourth interpolation point J13 is outside the screen. Therefore, the two roads R20 and R21 cross unintentionally in the bird's eye view of FIG. 12 due to an interpolation error.

  FIG. 13 is a diagram in which the display frame of the screen in FIG. 12 on which the bird's-eye view is displayed is converted into a reverse bird's-eye view and displayed in the two-dimensional map. A trapezoidal area T displayed as a bird's eye view, two roads R20 and R21, and interpolation points thereof are displayed in a two-dimensional window coordinate system. The Y coordinate of the upper side of the trapezoidal area T is Y2, and the Y coordinate of the lower side is Y1.

  The three interpolation points J0, J1, and J2 of the road R21 (corresponding to the three interpolation points J10, J11, and J12 in the three-dimensional window coordinate system of FIG. 12, respectively) exist in the trapezoidal area T, but are the fourth. The interpolation point J3 (corresponding to the interpolation point J13 in FIG. 12) exists outside the trapezoidal region T.

  Since the line segment connecting the third interpolation point J2 and the fourth interpolation point J3 intersects with the lower side of the trapezoidal region T at the intersection J4, the interpolation point adding unit 70 adds the intersection J4 as a new interpolation point of the road R21.

  FIG. 14 is a diagram illustrating a bird's-eye view drawn by performing bird's-eye view conversion using newly added interpolation points. Since a new interpolation point J4 is added to the road R21 at the lower side of the trapezoidal region T, the road R21 does not intersect the road R20 on the lower side of the screen even if the bird's-eye view conversion is performed, and the bird's-eye view is drawn accurately.

  A case where an interpolation point is set on the right side of the trapezoidal area will be described with reference to FIGS. FIG. 15 is a bird's eye view showing two roads R30 and R31 and their interpolation points in a three-dimensional window coordinate system. The three interpolation points K10, K11, K12 of the road R31 are on the screen, but the fourth interpolation point K13 is outside the screen. Therefore, due to the interpolation error, the two roads R30 and R31 cross unintentionally in the bird's eye view of FIG.

  FIG. 16 is a diagram in which the display frame of the screen in FIG. 15 on which the bird's-eye view is displayed is converted into a reverse bird's-eye view and displayed in the two-dimensional map. A trapezoidal area T displayed as a bird's eye view, two roads R30 and R31, and their interpolation points are displayed in a two-dimensional window coordinate system.

  The three interpolation points K0, K1, and K2 of the road R31 (corresponding to the three interpolation points K10, K11, and K12 in the three-dimensional window coordinate system of FIG. 15) exist in the trapezoidal area T, but the fourth one. The interpolation point K3 (corresponding to the interpolation point K13 in FIG. 15) exists outside the trapezoidal region T.

  Since the line segment connecting the third interpolation point K2 and the fourth interpolation point K3 intersects the right side of the trapezoidal region T at the intersection K4, the interpolation point adding unit 70 adds this intersection K4 as a new interpolation point of the road R31.

  FIG. 17 is a diagram illustrating a bird's-eye view drawn by performing bird's-eye view conversion using newly added interpolation points. Since a new interpolation point K4 is added to the road R31 on the right side of the trapezoidal region T, even if the bird's-eye view conversion is performed, the road R31 does not intersect the road R30 on the right side of the screen, and the bird's-eye view is accurately drawn.

  The present invention has been described based on the embodiments. The embodiments are exemplifications, and it will be understood by those skilled in the art that various modifications can be made to combinations of the respective constituent elements and processing processes, and such modifications are within the scope of the present invention. .

The method for creating a bird's-eye view by adding interpolation points described in this embodiment is a method for performing bird's-eye view conversion of other node information such as a river or a railway that draws a line by connecting the interpolation points and the interpolation points regardless of road drawing. It can also be applied to.
In addition, the present invention is naturally applicable to bird's-eye view generation by a conversion method other than the bird's-eye view conversion described in the present embodiment.

  DESCRIPTION OF SYMBOLS 1 Navigation apparatus, 2 Position detection apparatus, 3 Information storage part, 4 User interface part, 5 Information processing part, 51 Arithmetic apparatus, 60 Affine conversion part, 62 Bird's eye view conversion part, 64 Line drawing part, 66 Display part, 68 Reverse Bird's eye view conversion unit, 70 Interpolation point addition unit.

Claims (7)

A map information storage unit for storing map information including information on a plurality of interpolation points for forming a line;
The reverse of the interpolation point conversion processing for bird's-eye view generation for the display frame of the screen displaying the bird's-eye view when it is assumed that the two-dimensional map drawn based on the map information is looked down from a predetermined viewpoint position. An inverse conversion processing unit for obtaining a rectangular area on a two-dimensional map displayed as a bird's eye view by performing a conversion process;
An interpolation point adding unit that exists on or in the side of the rectangular area and adds a point for forming a line between existing adjacent interpolation points as a new interpolation point of the line;
A drawing processing apparatus comprising: a bird's eye view generation unit configured to generate the bird's eye view by performing the conversion process on an interpolation point for forming a line including an added interpolation point.   The interpolation point adding unit, when a line segment formed by sequentially connecting existing interpolation points intersects any side of the rectangular area, adds the intersection as a new interpolation point of the line. The drawing processing apparatus according to claim 1.   The interpolation point adding unit, when a line segment formed by sequentially connecting existing interpolation points and an upper side with respect to the screen of the rectangular area intersect, the intersection of the upper side with the new side of the line The drawing processing apparatus according to claim 2, wherein the drawing processing apparatus adds the interpolation points as simple interpolation points.   The interpolation point adding unit, when a line segment formed by sequentially connecting existing interpolation points and a lower side of the rectangular region with respect to the screen intersect the intersection of the lower side with the line The drawing processing apparatus according to claim 2, wherein the drawing processing device is added as a new interpolation point.   The interpolation point adding unit obtains the density of interpolation points for a plurality of lines existing in the rectangular area, and skips the process of adding a new interpolation point for lines whose interpolation point density is higher than a predetermined threshold. The drawing processing apparatus according to claim 1, wherein: Referencing from the memory map information including information about a plurality of interpolation points to form a line;
The reverse of the interpolation point conversion processing for bird's-eye view generation for the display frame of the screen displaying the bird's-eye view when it is assumed that the two-dimensional map drawn based on the map information is looked down from a predetermined viewpoint position. Obtaining a rectangular region on a two-dimensional map displayed as a bird's-eye view by performing a conversion process;
Adding a point that is on or inside a side of the rectangular area and that is between existing adjacent interpolation points to form a line as a new interpolation point of the line;
And a step of generating the bird's-eye view by performing the conversion process on the interpolation points for forming the line including the added interpolation points. A function for referring to map information including information on a plurality of interpolation points for forming a line from a memory;
The reverse of the interpolation point conversion processing for bird's-eye view generation for the display frame of the screen displaying the bird's-eye view when it is assumed that the two-dimensional map drawn based on the map information is looked down from a predetermined viewpoint position. A function for obtaining a rectangular area on a two-dimensional map displayed as a bird's eye view by performing a conversion process;
A function that exists on or in the side of the rectangular area and that is between existing adjacent interpolation points and forms a line as a new interpolation point of the line;
A drawing processing program characterized by causing a computer to realize the function of generating the bird's eye view by performing the conversion process on an interpolation point for forming a line including an added interpolation point.

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