JP2009250714A - Road guidance display device and road guidance display method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a road guidance display device and a road guidance display method capable of reducing the burden on a driver viewing a road guidance information by improving the difficulty in viewing when a foreground peripheral area image and the road guidance information are displayed superimposed. <P>SOLUTION: The road guidance display device includes: a peripheral area-image taking camera 107 for taking an image of the foreground of the traveling direction of a vehicle as a peripheral area image; a display device 112 for displaying the peripheral area-image, a vehicle position detection part 102 for detecting the present position of the vehicle; a map database 104 for storing the connecting relation of the roads, wherein a route searching part 103 searches a route ahead based on the database 104 in accordance with an operator's instruction and the present position of the vehicle, and a route image composition part 111 superimposes a route picture on the part corresponding to the sky out of the display images of the display device 112. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a road guidance display device and a road guidance display method, and more particularly to a road guidance display device and a road guidance display method for displaying road guidance information superimposed on a foreground peripheral image.

  In recent years, for drivers who are not good at understanding map information such as car navigation systems, the landscape in front of the vehicle is captured as a camera image for the purpose of assisting in reading map information and reducing the burden of recognition. Attempts to superimpose and display road guidance graphics and the like and display them on an in-vehicle monitor have been made.

For example, in the “vehicle guidance display device” disclosed in Japanese Patent Laid-Open No. 10-281795, a foreground camera image captured on-time by an in-vehicle camera, that is, a peripheral image in front of the vehicle is displayed on an in-vehicle monitor, A method of superimposing and displaying guidance information (intersection traveling direction instruction, lane change instruction, etc.) has been proposed.
Japanese Patent Laid-Open No. 10-281795

  However, in the technique disclosed in Patent Document 1 described above, it is full of guidance to display an intersection several hundred meters ahead on the vehicle-mounted monitor, and if it is attempted to guide and display the intersection ahead, the vicinity of the horizontal line Because information gathers, it becomes extremely difficult to see. Therefore, there has been a situation that it is difficult to confirm the traveling direction of the next two or three intersections by guidance display.

  The present invention has been made in view of the above-described conventional circumstances, and improves the difficulty in displaying road guidance information superimposed on the foreground peripheral image, thereby reducing the burden on the driver who recognizes the road guidance information. An object of the present invention is to provide a road guidance display device and a road guidance display method that can be realized.

  In order to solve the above-described object, the present invention is characterized in that a route map searched for a route is displayed by being superimposed on a portion corresponding to the sky in a display image ahead of the vehicle traveling direction.

  According to the present invention, it is difficult to see information due to the collection of information near the horizon, and the traveling direction of two to three intersections can be easily confirmed by the guidance display. As a result, the road guidance information is recognized. This reduces the burden on the driver.

  Hereinafter, embodiments of the road guidance display device and the road guidance display method of the present invention will be described in detail in the order of [Embodiment 1], [Embodiment 2], and [Embodiment 3] with reference to the drawings.

[Example 1]
FIG. 1 is a configuration diagram of a road guidance display device according to Embodiment 1 of the present invention. In the figure, a road guidance display device according to the present embodiment includes a destination input unit 101, a host vehicle position detection unit (host vehicle position detection unit) 102, a route search unit (route search unit) 103, a map database 104, a route guidance. Unit 105, coordinate conversion type storage unit 106, peripheral video imaging camera (peripheral video imaging means) 107, guide arrow video generation unit 108, guide arrow video synthesis unit 109, route video conversion unit (video conversion unit) 110, route video synthesis And a display device (display means) 112.

  The destination input unit 101 is a touch panel installed, for example, on the display screen of the display device 112, and sets a destination based on an address or a telephone number. This input and set information is sent to the in-vehicle computer 130.

  The own vehicle position detection unit 102 is a GPS receiver, for example, and calculates the current position of the own vehicle based on information sent from a satellite. The calculated position information is sent to the in-vehicle computer 130.

  The peripheral video photographing camera 107 is composed of a vehicle-mounted camera made up of a CCD image sensor or the like, and the photographed peripheral video is converted into an electrical video signal and sent to the vehicle-mounted computer 130.

  The display device 112 displays a composite screen created by the in-vehicle computer 130, that is, a composite image for car navigation, on the display screen, and is composed of, for example, a liquid crystal display.

  In addition, among the listed constituent elements, other constituent elements other than the destination input unit 101, the own vehicle position detection unit 102, the peripheral video camera 107, and the display device 112, that is, the route search unit 103, the map database 104, the route The guidance unit 105, the coordinate conversion type storage unit 106, the guidance arrow video generation unit 108, the guidance arrow video synthesis unit 109, the route video conversion unit 110, and the route video synthesis unit 111 are processing programs and data in the in-vehicle computer 130. That is, the in-vehicle computer 130 is realized by, for example, a processor such as a CPU, MPU (microprocessor) or DSP (digital signal processor), a memory such as RAM or ROM, and an interface unit with an external device group, and a route search unit. 103, a route guidance unit 105, a coordinate conversion type storage unit 106, a guide arrow image composition unit 109, and a route image composition unit 111 are programs stored in a memory and executed on a processor.

  The route search unit 103 searches for a route from the current position to the destination, and searches for a minimum cost route using, for example, the Dijkstra method. The route search unit 103 reads map data from the map database 104 based on the destination information by the destination input unit 101 and the current position information by the host vehicle position detection unit 102, and the route from the current position to the destination. And the route feature amount of the route.

  In addition, the route guidance unit 105 extracts information on a road on the route to the destination from the roads near the current position of the host vehicle based on the route and the route feature amount, and outputs the information as guidance route information To do.

  In addition, the guide arrow image generation unit 108 that generates a guide graphic of the traveling direction of the vehicle generates a guide arrow to be displayed on the display image of the display device 112 for road guidance based on the guide route information from the route guide unit 105. Is to be generated. In the present embodiment, a guide arrow is used as a guide figure for guiding the traveling direction of the vehicle. However, the guide figure is not limited to the guide arrow, and for example, the progress of the vehicle The direction may be guided by an appropriate color circle mark or blinking display of a vehicle graphic, or any figure may be used.

  The guide arrow video composition unit 109 synthesizes and outputs the guide arrow (guide graphic) generated by the guide arrow video generation unit 108 with the surrounding video image taken by the peripheral video camera 107. .

  In addition, the route image conversion unit 110 converts the route map based on the guide route information of the route guide unit 105 into the vertical direction and / or the horizontal direction of the route map based on the coordinate conversion formula stored in the coordinate conversion formula storage unit 106. Enlarge or compress to convert to bird's eye view.

  Further, the route video synthesis unit 111 superimposes the route map of the bird's eye view converted by the route video conversion unit 110 on the portion corresponding to the sky in the front peripheral video synthesized by the guide arrow video synthesis unit 109. To synthesize. This synthesized video is output to the display device 112 for car navigation.

  With the configuration as described above, in the road guidance display device according to the present embodiment, a route search step (in accordance with an instruction from the operator via the destination input unit 101 and the current position of the host vehicle by the host vehicle position detection unit 102). A route search unit 103) searches for a previous route based on the map database 104, a route guidance unit 105 extracts guidance route information, and a video conversion step (route video conversion unit 110) performs a route based on the guidance route information. The figure is converted into a bird's-eye view display by enlarging or compressing the vertical direction and / or horizontal direction of the route map based on the coordinate conversion formula stored in the coordinate conversion formula storage unit 106, and further, a video composition step (route video) The combining unit 111) superimposes the bird's-eye view path map on the portion corresponding to the sky in the front peripheral video, and displays it on the display device 112.

  Next, an outline of a method for enlarging or compressing the vertical and / or horizontal directions of the route map based on the coordinate conversion formula in the image conversion step (route image conversion unit 110) of the present invention will be described with reference to FIGS. This will be described in detail.

  Here, any figure of FIGS. 2-6 has shown the example of a display of the road map which has an intersection ahead. FIG. 2 is a display example viewed from above the road map as a plan view, and FIG. 3 is a display example of a bird's eye view viewed from the road map. FIG. 4 is a display example showing an enlarged bird's-eye view when the bird's-eye display shown in FIG. 3 is simply enlarged only in the vertical direction. For each area obtained by appropriately dividing the bird's-eye view shown in FIG. As an example, the enlarged bird's-eye view is enlarged n times as long as the ratio n · y1: n · y2: n · y3: n · y4 with the vertical ratio y1: y2: y3: y4 maintained as it is. ing.

  FIG. 5 illustrates an overall enlarged bird's-eye view when the plan view of FIG. 2 taken with the road viewed is enlarged and reduced so that the ratio between the vertical direction and the horizontal direction is constant. When the vertical direction is enlarged n times by the ratio n · y1: n · y2: n · y3: n · y4, n · x1: n · x2: n · x3: n · x4 is similarly applied to the horizontal direction. And a similar transformation obtained by enlarging n times. That is, in the overall enlarged bird's eye view of FIG. 5, the relationship of the vertical and horizontal ratios a: b = a ′: b ′ = a ″: b ″ = a ′ ″: b ′ ″ of each area before conversion is expanded.・ Established even after reduction conversion.

  Further, FIG. 6 exemplifies a partially enlarged bird's-eye view in the case of enlarging / reducing conversion so that the ratio between the vertical direction and the horizontal direction is constant for a part of the attention area of the bird's-eye view display of FIG. When the vertical direction is enlarged n times by the ratio n · y1: n · y2: n · y3: n · y4 only for a part of the area of interest, n · x1: n · x2: n · x3: n · x4 and similar transformation obtained by enlarging n times. That is, in the partially enlarged bird's-eye view display of FIG. 6, for only the area of interest, the aspect ratio of each area before conversion a: b = a ′: b ′ = a ″: b ″ = a ′ ″: b The relationship of '' 'is established even after enlargement / reduction conversion.

  In the case of a flat display such as the plan view of FIG. 2, intersections and curves far ahead can be faithfully displayed on the screen as the actual shape, so the driver can identify the intersections and curves ahead from the road map. There is no particular problem with the above. However, this road map is displayed superimposed on the front peripheral image on the display screen, and is superimposed on the partial area corresponding to the sky in the front peripheral video from the viewpoint of easy viewing. It is difficult to display all the route maps to the destination in a limited display area in a flat display. Therefore, it is conceivable to display a route map to the destination in the display area limited by the bird's-eye view display as shown in FIG. 3, but in this bird's-eye view display, intersections and curves far ahead are in the vertical direction. It will be crushed and displayed on the screen, making it difficult for the driver to read the map information accurately.

  As a technique for solving this problem, a method of converting only the vertical direction of the video displayed in a collapsed manner in FIG. 3 into an enlarged bird's eye view enlarged by n times according to the ratio of each area in FIG. 3 (FIG. 4). Can be considered. However, on the display screen in which only the vertical direction that is collapsed and displayed is simply enlarged as shown in the enlarged bird's-eye view shown in FIG. 4, the shape of the intersection or the curve itself will be destroyed. However, it is different from the actual shape, and it is a screen display that makes it difficult for a driver who is not good at recognizing map information to identify intersections and curves. In other words, simply expanding in the vertical or horizontal direction changes the shape of roads such as intersections and curves, making the display difficult to understand. Can not be reduced.

  On the other hand, as shown in the whole bird's-eye display in FIG. 5 and the partial bird's-eye display in FIG. 6, the ratio of the vertical and horizontal directions of each area before conversion: a: b = a ′: b ′ = a ″: b ″ = a ′ ″ : When similar transformation is performed so that the ratio of b ″ ′ is established even after enlargement / reduction transformation, the screen is enlarged and displayed in a state where the intersection and the curve shape existing in front are retained. Thus, even a driver who is not good at recognizing map information can display a screen that can easily identify intersections, curves, and the like.

  That is, according to the present invention, as shown in the whole bird's-eye view display of FIG. 5 or the partial bird's-eye view display of FIG. 6, the coordinate conversion reflecting the actual road shape is performed, thereby expanding and compressing in the vertical direction and the horizontal direction. The ratio is made the same in the entire route display or in the area of interest, and the shape such as an intersection or a curve in front of the vehicle can be reflected on the screen and displayed on the screen. In other words, the ratio of the scale ratio from the actual size of the actual road map is approximately the same in the vertical and horizontal directions according to the area of interest, and the shape of intersections and curves in front of the vehicle is approximately The screen can be displayed accurately. In other words, by maintaining a similar shape while maintaining the aspect ratio of the area of interest to be constant and converting it to display on the screen, the map information reading support for the driver is strengthened, and the driver's burden of recognizing road guidance information is reduced. It becomes possible to reduce.

  Next, in the route image conversion unit 110 of the present embodiment, a coordinate conversion formula for converting the route map based on the guide route information of the route guide unit 105 into a bird's eye view by expanding or compressing the vertical direction and / or the horizontal direction ( The coordinate conversion formula (stored in the coordinate conversion formula storage unit 106) will be described in detail with reference to FIGS.

  In general, when converting an arbitrary point on the upper surface coordinates of the plan view that accurately reflects the actual dimensions, such as a road map, to the coordinates of the bird's eye view display, the conversion may be performed as follows. For example, in the case of the positional relationship as shown in FIG. 7, with respect to the coordinate Y in the vertical direction (Y direction) of the top view coordinate of the plan view indicating the road map coordinates, It can be converted by mathematical formulas. FIG. 7 is an explanatory diagram for explaining a coordinate conversion formula (Y direction) for converting an arbitrary point Y in the Y direction on the upper surface coordinates into a point y on the display coordinates in the bird's eye view display.

That is, the y-direction coordinate y of the bird's-eye view display coordinate is
(Equation 1)
y = −DS · tan θ−DS · tan ω = −DS (tan θ + tan ω) (1)
As given. Further, an arbitrary point Y on the upper surface coordinates is given by the following equation 2.

(Equation 2)
Y = [h / sin (θ + ω)] · (cosω / sinθ) + c (2)
Here, when Formula 2 is further rearranged, the following Formula 3 is obtained.

(Equation 3)
Y = [h / (tan θ + tan ω)] · (1 / cos 2θ) + c (3)
Therefore, as a coordinate conversion formula for converting the upper surface coordinate Y to the bird's-eye display coordinate y from Equation 1 and Equation 3, the following is given between the point y on the bird's-eye display coordinate and the point Y on the upper surface coordinate: The relationship of Formula 4 is established.

(Equation 4)
Y = (− h · DS / cos 2θ) · (1 / y) + c (4)
Here, the relationship in the first parenthesis of Equation 4 is given using a constant b as shown in Equation 5 below.

(Equation 5)
b = h · DS / cos 2θ (5)
That is, when the coordinate conversion formula of Formula 4 is expressed using the constant b, the bird's eye view display coordinate y with respect to the coordinate Y in the Y direction of the top surface coordinate (map coordinate) has the relationship shown in Formula 6 below.

(Equation 6)
Y = (− b / y) + c (6)
In the route video conversion unit 110, depending on the case, for the entire route map or a specific area of interest, the vertical direction may be further crushed so that a correct sense of distance can be easily recognized. The coordinate conversion formula shown in FIG. 6 may be further modified so as to be compressed or expanded at unequal intervals in the vertical direction. As a specific example, as shown in the following Expression 7, correction is performed using a value obtained by multiplying an arbitrary point (x, y) in the x direction and y direction on the display by the correction amount d. Anyway.

(Equation 7)
Y = (− b / y) −d · x · y + c (7)
In addition, in order to make it easier to grasp the correct road shape more accurately by similar shape conversion with a constant ratio of expansion / compression ratio in the vertical direction and the horizontal direction, not only in the vertical direction (Y direction), Similarly, the lateral direction (X direction) may be modified so as to be compressed or expanded at unequal intervals.

  On the other hand, when converting an arbitrary point on the top surface coordinates of the plan view that accurately reflects the actual dimensions, such as road map data, to the coordinates of the bird's eye view display, the coordinates X in the X direction orthogonal to the Y direction on the top surface coordinates For example, as shown in FIG. 8, the relationship of the following expression 8 is established between the display coordinates on the display screen and the coordinates x in the x direction. FIG. 8 is an explanatory diagram for explaining a coordinate conversion formula (X direction) for converting an arbitrary point X in the X direction on the upper surface coordinates into a point x on the display coordinates in the bird's eye view display.

(Equation 8)
X / {(Y−c) · cos θ} = x / DS (8)
Further rearranging Equation 8 yields Equation 9 below.

(Equation 9)
X = (cos θ / DS) · x · (Y−c) (9)
Further, when (Yc) in Expression 9 is transformed using Expression 6, the coordinate conversion expression from the upper surface coordinate X to the display coordinate x is expressed by the point x on the display coordinate and the point X on the upper surface coordinate. In the meantime, the relationship of the following formula 10 is established.

(Equation 10)
X = (cosθ / DS) · x · (−b / y)
= −b · (cos θ / DS) · (x / y) (10)
Here, the relationship up to the first parenthesis of Equation 10 is given using a constant a as shown in Equation 11 below.

(Equation 11)
a = b · (cos θ / DS) (11)
That is, when the coordinate conversion expression of Expression 10 is expressed using the constant a, the coordinate X on the top surface coordinate (X direction) with respect to the coordinate x on the bird's eye display coordinates is related to the coordinate y in the y direction on the display coordinates. In this form, the relationship shown in the following Expression 12 is obtained.

(Equation 12)
X = −a · (x / y) (12)
As described above, the conversion of the route map based on the guidance route information to the bird's eye view display by the route guidance unit 105 is performed with specific numerical values (for the constants a, b, and c in the equations (6) and (12)). That is, by assigning a value corresponding to the viewpoint, the display range, etc.), an arbitrary point X, Y on the top surface coordinates indicating the map coordinates is actually used by using the coordinate conversion expressions of Expression 6 and Expression 12. It is possible to convert to a coordinate position (x, y) for bird's-eye view display.

  Further, with respect to the coordinate transformation formula relating to the X direction, that is, the formula 12, as the image moves away from the center line to the left and right so that a correct distance can be recognized not only in the front front direction but also in the diagonally forward direction. The lateral coordinate X may be modified so that the lateral length becomes longer. As a specific example, as shown in the following equation 13, correction is performed using a value obtained by multiplying the square value of an arbitrary point x in the x direction on the display image by the correction amount d. Also good.

(Equation 13)
X = −a · (x / y) −d · x ² (13)
In this case, the coordinate conversion formula from the top image to the bird's-eye view display coordinate corrected in the horizontal direction is a specific numerical value (that is, the constant a, b, c, d in each of the formulas 6 and 13 (that is, By substituting values corresponding to the viewpoint, display range, and the like, any point X, Y on the top surface coordinate can be converted to a coordinate position (x, y) on the bird's-eye view display.

  A specific screen display example of the display device 112 by the road guidance display device of the present embodiment is shown in FIGS. FIG. 9 exemplifies a display image obtained by combining the guide arrow generated by the guide arrow image generation unit 108 by the guide arrow image combining unit 109 with the surrounding image captured in front of the host vehicle captured by the peripheral image capturing camera 107. ing.

  Further, FIG. 10 superimposes and composites the bird's eye view path map converted and generated by the path video conversion unit 110 on the video in FIG. 9 on the portion corresponding to the sky in the front peripheral video. The display image is illustrated.

  In FIG. 10, only the route from which the road map is omitted is displayed as a route map. However, this may be used for navigation even if the route map is limited to a partial area corresponding to the sky in the front peripheral video. If the road map is used as it is, it is cumbersome and difficult to see. Therefore, the display is simplified in order to enhance the intuitive recognition of the driver. In this display example, a circle mark is given to the destination, and a circle mark of an appropriate color (for example, different from the destination) is given to the intersection.

  In addition, about the route map to display, it is also possible to perform stepwise setting according to the amount of information to be included. That is, the driver may be able to select and set only a simplified route shape display, a display with main place names or building names, and the like.

  As described above, in the road guidance display device and the road guidance display method according to the present embodiment, the peripheral video photographing camera 107 that photographs the front in the traveling direction of the vehicle as the peripheral video, the display device 112 that displays the peripheral video, the vehicle In a road guidance display device comprising a host vehicle position detection unit 102 for detecting the current position of the vehicle and a map database 104 storing road connection relations, the route search unit 103 (route search step) The route is searched based on the map database 104 according to the direction of the vehicle and the current position of the host vehicle, and the route map corresponds to the sky in the display video of the display device 112 by the route video synthesis unit 111 (video synthesis step). It is displayed superimposed on the part to be. This eliminates the extreme difficulty of gathering information near the horizon, and the traveling direction of the next two or three intersections can be easily confirmed by the guidance display. As a result, the road guidance information is recognized. The burden on the driver can be reduced.

  In the road guidance display device and the road guidance display method of the present embodiment, the route image conversion unit 110 (image conversion step) enlarges or compresses the vertical direction and / or the horizontal direction of the route map of the coordinate conversion type storage unit 106. Based on the coordinate conversion formula, the route map is converted into a bird's-eye view display, and the route image synthesis unit 111 (image synthesis step) superimposes and displays the bird's-eye view route map on the portion of the display image of the display device 112 corresponding to the sky. To do. In this way, the route map to the destination can be displayed in a display area limited by the bird's eye view route map, and the vertical crushing is alleviated by the conversion based on the coordinate conversion formula, and a certain amount of front is fixed. In the distance range, the intersection angle of the intersection can be easily understood, and it is easy to confirm the place to bend.

  Further, in the road guidance display device of the present embodiment, the coordinate conversion formula in the coordinate conversion formula storage unit 106 is set so that the vertical or horizontal expansion or compression of the route map is performed at unequal intervals. That is, by appropriately setting specific values to be substituted for the constants a, b, c, and d in the coordinate conversion equations (Equation 7 and Equation 12) according to the viewpoint, the display range, and the like, The compression or expansion can be made at unequal intervals, which reduces the vertical collapse, makes it easier to see the intersection angle of the intersection in the front area of interest, and makes it easier to see where to turn it can.

  Further, in the road guidance display device of the present embodiment, the coordinate transformation formula of the coordinate transformation formula storage unit 106 is set so that the lateral length increases as the distance from the center increases or decreases in the horizontal expansion or compression of the route map. It is set. In other words, the specific values to be substituted for the constants a, b, c, and d in the coordinate conversion formulas (Formula 6 and Formula 13) are set appropriately according to the viewpoint, the display range, and the like, thereby moving away from the center line to the left and right. Accordingly, it is possible to increase the lateral length, thereby making it easy to understand the crossing angle of not only the front front but also the diagonally forward crossing and making it easier to confirm the place to bend.

[Example 2]
Next, a road guidance display device and a road guidance display method according to Embodiment 2 of the present invention will be described. The configuration of the road guidance display device of the present embodiment is the same as that of the first embodiment (FIG. 1), but the bird's-eye view of a predetermined attention area in the conversion of the route map into the bird's-eye view display performed by the route image conversion unit 110. The ratio of the expansion or compression ratio in the vertical and horizontal directions of the displayed route map is a constant ratio, or the expansion or compression ratio in the vertical and horizontal directions of the path diagram of the bird's eye view is substantially the same. Is converted so that

  As described in the first embodiment in the outline explanation (see FIGS. 2 to 6) of the method of enlarging or compressing the vertical and / or horizontal directions of the route map based on the coordinate conversion formula in the route image conversion unit 110, the actual road Depending on the area of interest, the ratio of the scale ratio from the actual size of the map is approximately the same in the vertical and horizontal directions, and the shape of intersections and curves in front of the vehicle can be displayed on the screen almost accurately. Enhances the support for reading map information for the driver and reduces the burden on the driver who recognizes the road guidance information by maintaining the similar shape while maintaining the same aspect ratio of the area of interest and converting it to display on the screen. It becomes possible to do.

  Hereinafter, a coordinate conversion formula in which the ratio of the expansion or compression rate in the vertical direction and the horizontal direction is set to a constant ratio, or the expansion or compression rate in the vertical direction and the horizontal direction is made substantially the same will be described in detail.

  First, a method for making the ratio of the vertical enlargement / compression ratio and the horizontal enlargement / compression ratio constant in a predetermined area as the attention area will be described. Here, it is assumed that the upper surface coordinates (X, Y) and the bird's eye view display coordinates (x, y) satisfy the following expressions 14 and 15. It is assumed that Expression 14 that gives an arbitrary point Y in the Y direction is the same as Expression 7 in the first embodiment.

(Equation 14)
Y = (− b / y) −d · x · y + c (14)
(Equation 15)
X = f (x) (15)
Differentiating Equation 14 and Equation 15 respectively yields Equation 16 and Equation 17 below.

(Equation 16)
dY / dy = b / y ² −d · x (16)
(Equation 17)
dX / dx = df (x) / dx (17)
That is, Expression 16 means that the value of dY / dy proportional to the vertical expansion / compression ratio is {b / y ² −d · x}, while Expression 17 expresses the horizontal expansion / compression ratio. It means that the value of dX / dx proportional to the compression rate is {df (x) / dx}.

  Therefore, in order to make the ratio of the vertical enlargement / compression rate and the horizontal enlargement / compression rate constant, the following Expression 18 may be established in the date-of-day area.

(Equation 18)
dX / dx = k · dY / dy (18)
Here, k is a constant. When the condition of Expression 18 is satisfied, the following Expression 19 and Expression 20 can be obtained from Expression 16 and Expression 17.

(Equation 19)
df (x) / dx = k · b / y ² −k · d · x (19)
(Equation 20)
f (x) = k · b · (x / y 2) -k · d · x 2/2 ... (20)
That is, if coordinate transformation is performed by the following formulas 21 and 22, the ratio of the vertical expansion / compression ratio and the horizontal expansion / compression ratio can be given by a constant k in the area of interest. It is possible to display on the screen a bird's-eye view display image in which the relative distance is more easily recognized while matching the ratios and reflecting the actual dimensions more correctly. The expression 21 for giving an arbitrary point Y in the Y direction is the same as the expression 14, and the expression 22 for giving an arbitrary point X in the X direction is described above in {f (x)} of the expression 15. Equation 20 is substituted.

(Equation 21)
Y = (− b / y) −d · x · y + c (21)
(Equation 22)
X = k · b · (x / y 2) -k · d · x 2/2 ... (22)
By substituting specific numerical values (that is, values corresponding to the viewpoint, display range, etc.) for the constants b, c, d, and k in the equations 21 and 22, the equations 21 and 22 are obtained for arbitrary points X and Y. Using the coordinate conversion formula of Formula 22, the coordinate position on the bird's eye view with the same ratio of the enlargement / compression rate in the Y direction (vertical direction) and the horizontal direction (X direction) in the attention area can be calculated. .

  Note that the condition of {dX / dx = k · dY / dy} is satisfied even when another function is used as the coordinate transformation expression, without being limited to the case where the functions such as Expression 21 and Expression 22 are used. Accordingly, it is possible to create a similar video display in which the ratio of the vertical / horizontal expansion / compression ratio is constant.

  Further, in some cases, if k = 1 is set within a predetermined range, it is possible to perform similar transformation that matches the enlargement / compression rate itself in the vertical and horizontal directions.

  FIG. 11 shows a specific screen display example of the display device 112 by the road guidance display device of the present embodiment. FIG. 11 is a display in which a bird's eye view route map converted and generated by the route image conversion unit 110 is superimposed and synthesized on a portion corresponding to the sky in the surrounding captured images taken by the surrounding image capturing camera 107. The image is illustrated. The figure shows an example in which a similar transformation is performed in which the enlargement / compression ratio in the vertical direction and the enlargement / compression ratio in the horizontal direction are substantially the same.

  As described above, in the road guidance display device according to the present embodiment, the coordinate conversion formula in the coordinate conversion formula storage unit 106 is enlarged in the vertical direction and the horizontal direction of the route diagram of the bird's eye view display within a preset range. Alternatively, the compression ratio is set to be a constant ratio. That is, by appropriately setting specific values to be substituted for the constants a, b, c, and d in the coordinate conversion equations (Equation 21 and Equation 22) according to the viewpoint, the display range, and the like, By matching the ratio of the enlargement / compression rate and the horizontal enlargement / compression rate as the ratio given by the constant k, it is possible to display the sense of distance more easily while correctly reflecting the actual shape. As a result, the map information reading support for the driver can be strengthened, and the burden on the driver who recognizes the road guidance information can be reduced.

  In the road guidance display device according to the present embodiment, the coordinate conversion formula stored in the coordinate conversion formula storage unit 106 has an expansion or compression ratio in the vertical direction and the horizontal direction of the route map of the bird's-eye view display within a preset range. It is set to be substantially the same. That is, by appropriately setting specific values to be substituted for the constants a, b, c, and d in the coordinate conversion equations (Equation 21 and Equation 22) according to the viewpoint, the display range, and the like, The enlargement / compression rate and the horizontal enlargement / compression rate are almost the same, and the actual shape can be reflected more correctly, while the sense of distance (especially in the horizontal direction) can be displayed more easily. The support for reading map information for the driver can be strengthened, and the burden on the driver who recognizes the road guidance information can be reduced.

Example 3
Next, a road guidance display apparatus according to the third embodiment will be described. In the present embodiment, a graphic image with grid lines is further superimposed on a region in which a route map or a bird's eye view route map is superimposed on the peripheral video in the first and second embodiments.

  FIG. 12 shows a configuration diagram of the road guidance display device of the present embodiment. Similar to the first embodiment (see FIG. 1), the configuration includes the destination input unit 101, the vehicle position detection unit 102, the peripheral video camera 107, and the display device 112, but the internal configuration of the in-vehicle computer 230 is implemented. Different from Example 1.

  That is, the in-vehicle computer 230 includes the route search unit 103, the map database 104, the route guidance unit 105, the coordinate conversion type storage unit 106, the guidance arrow image generation unit 108, and the guidance arrow image composition unit 109 provided in the in-vehicle computer 130 of the first embodiment. In this configuration, a graphic data storage unit 120 and a graphic superimposing unit 121 are added to the route image conversion unit 110 and the route image composition unit 111.

  The graphic data storage unit 120 stores graphic data with a grid line (a grid display) corresponding to the viewpoint position of the bird's eye view path diagram. The graphic superimposing unit 121 superimposes the graphic data stored in the graphic data storage unit 120 on the synthesized video of the surrounding video and the bird's eye view path map by the route video synthesizing unit 111 and synthesizes them. This synthesized video is output to the display device 112 for car navigation.

  With such a configuration, in the road guidance display device of the present embodiment, the route search unit 103 responds to an instruction via the operator's destination input unit 101 and the current position of the host vehicle by the host vehicle position detection unit 102. A previous route is searched based on the map database 104, guide route information is extracted by the route guide unit 105, and a route map based on the guide route information is stored in the coordinate conversion formula storage unit 106 by the route image conversion unit 110. The vertical and / or horizontal directions of the route map are enlarged or compressed based on the coordinate conversion formula converted into a bird's eye view display, and the route image synthesis unit 111 makes the route view of the bird's eye view empty in the front peripheral image. Further, the graphic superimposing unit 121 superimposes and synthesizes the image on the corresponding part. Was synthesized by superimposing the graphic data with a grid line in accordance with the viewpoint position of the figure (square display), displays this on the display device 112.

  FIG. 13 shows a specific screen display example of the display device 112 by the road guidance display device of the present embodiment. 13 superimposes and combines the bird's eye view route map converted and generated by the route image conversion unit 110 on the portion corresponding to the sky in the surrounding captured images in front of the host vehicle captured by the surrounding image capturing camera 107. Furthermore, a display image obtained by superimposing graphic data with grid lines (grid display) is illustrated.

  As described above, in the road guidance display device according to the present embodiment, the graphic superimposing unit 121 converts the graphic data with the grid lines corresponding to the viewpoint positions of the route diagram of the bird's eye display stored in the graphic data storage unit 120. It is displayed on the display device 112 so as to be superimposed on a composite image of the peripheral image and the bird's eye view route map by the route image composition unit 111. In this way, the grid lines are displayed in a superimposed manner, so that the driver can easily recognize a three-dimensional sense of distance, the intersection angle of the intersection located in front is easier to understand, and it is easier to confirm the place to bend. As a result, the map information reading support for the driver can be strengthened, and the burden on the driver who recognizes the road guidance information can be reduced.

It is a block diagram of the road guidance display apparatus which concerns on Example 1 of this invention. It is explanatory drawing which illustrates the example of a display seen as a plan view from the upper part of a road map. It is explanatory drawing which illustrates the example of a display of the bird's-eye view which looked down at the road map. It is explanatory drawing which illustrates the example of a display which expanded the bird's-eye view display of FIG. 3 only to the vertical direction. FIG. 4 is an explanatory diagram illustrating a display example in which the bird's eye view of FIG. 3 is enlarged / reduced and converted so that the ratio between the vertical direction and the horizontal direction is constant. FIG. 4 is an explanatory diagram illustrating a display example in which enlargement / reduction conversion is performed so that a ratio between a vertical direction and a horizontal direction is constant for an attention area in the bird's-eye view display of FIG. 3. It is explanatory drawing explaining the coordinate conversion type | formula (Y direction) which converts the arbitrary points Y of the Y direction on an upper surface coordinate into the point y on a display coordinate in bird's-eye view display. It is explanatory drawing explaining the coordinate conversion type | formula (X direction) which converts the arbitrary points X of the X direction on an upper surface coordinate into the point x on a display coordinate in bird's-eye view display. It is explanatory drawing which illustrates the display image which synthesize | combined the guidance arrow with the periphery image | video. It is explanatory drawing which illustrates the display image which superposed | combined and combined the path | route figure of the bird's-eye view display on the image | video of FIG. It is explanatory drawing which illustrates the display image which superposed | combined the route map of the bird's-eye display on the periphery image | video (the expansion / compression rate of the vertical direction and the expansion / compression rate of the horizontal direction are substantially the same). It is a block diagram of the road guidance display apparatus of Example 3. It is explanatory drawing which illustrates the display image which superimposed and combined the graphic data on the synthetic | combination image | video which superimposed the route map of the bird's-eye view display on the periphery image | video.

Explanation of symbols

101 Destination input unit 102 Own vehicle position detection unit (own vehicle position detection means)
103 Route search unit (route search means)
DESCRIPTION OF SYMBOLS 104 Map database 105 Route guidance part 106 Coordinate conversion type | formula memory | storage part 107 Peripheral image photographing camera (Ambient image photographing means)
108 Guide arrow video generation unit 109 Guide arrow video synthesis unit 110 Route video conversion unit (video conversion means)
111 Path image composition unit (image composition means)
112 Display device (display means)
120 graphic data storage unit 121 graphic superimposing unit 130, 230 vehicle-mounted computer

Claims (9)

Peripheral image photographing means for photographing the front of the vehicle in the traveling direction as a peripheral image;
Display means for displaying the peripheral video;
Own vehicle position detection means for detecting the current position of the vehicle;
A map database that stores road connections;
Route search means for searching for a previous route based on the map database according to an instruction from the operator and the current position of the host vehicle;
Video composition means for superimposing and displaying a route map by the route search means on a portion corresponding to the sky in the display image of the display means;
A road guidance display device comprising: Image conversion means for converting the route map into a bird's eye view based on a coordinate conversion formula for enlarging or compressing the vertical and / or horizontal directions of the route map;
2. The road guidance display device according to claim 1, wherein the video composition unit superimposes and displays the bird's eye view route map on a portion corresponding to the sky in the display video of the display unit.   3. The road guidance display device according to claim 2, wherein the coordinate conversion formula is set so that vertical and / or horizontal expansion or compression of the route map is performed at unequal intervals.   4. The coordinate transformation formula is set so that the lateral length increases as the distance from the center increases or decreases in the lateral expansion or compression of the route map. The road guidance display device according to any one of the above.   The coordinate transformation formula is set so that a ratio of expansion or compression ratio between the vertical direction and the horizontal direction of the path diagram of the bird's eye view display is a constant ratio within a preset range. The road guidance display device according to any one of claims 2 to 4.   The coordinate transformation formula is set so that enlargement or compression ratio in the vertical direction and the horizontal direction of the path diagram of the bird's-eye view display is substantially the same within a preset range. The road guidance display device according to any one of claims 2 to 4. Graphic data storage means for storing graphic data with grid lines corresponding to the viewpoint position of the bird's eye view path diagram;
Graphic superimposing means for displaying the graphic data stored in the graphic data storage means on the display means by superimposing them on the synthesized video of the peripheral video and the route map or the bird's eye view path map by the video synthesizing means; The road guidance display device according to any one of claims 1 to 6, further comprising: Peripheral image photographing means for photographing the front in the traveling direction of the vehicle as a peripheral image, display means for displaying the peripheral image, own vehicle position detecting means for detecting the current position of the vehicle, and a road connection relationship are stored. A road guidance display method of a road guidance display device comprising a map database,
A route search step for searching for a previous route based on the map database according to an operator's instruction and the current position of the host vehicle;
A video composition step of superimposing and displaying a route map obtained by the route search step on a portion corresponding to the sky in the display video of the display means;
A road guidance display method comprising: A video conversion step of converting the route map into a bird's eye view based on a coordinate conversion formula for enlarging or compressing the vertical and / or horizontal directions of the route map,
9. The road guidance display method according to claim 8, wherein the video composition step displays the bird's eye view route map superimposed on a portion corresponding to the sky in the display video of the display means.

Images