Patent Publication Number: US-11391592-B2

Title: Display system for augmented reality route section determination

Description:
TECHNICAL FIELD 
     The present disclosure relates to a display system to be used as, for example, an in-vehicle display system. 
     BACKGROUND ART 
     As a display apparatus, a head-up display (hereinafter, also referred to as an HUD) is known. The HUD can realize so-called AR (Augmented Reality) by projecting an image on a translucent display medium and presenting to a user this image so as to be superimposed on an object which can be seen through the display medium. 
     An in-vehicle HUD includes a display apparatus of a type which presents to a driver, information which supports driving, or the like, in front of a windshield as a virtual image which can be seen so as to be superimposed on actual scenery. This type of display apparatus is disclosed in, for example, PTL 1, PTL 2, or the like. 
     The in-vehicle HUD includes an H-ID which displays an AR route as a virtual image. Display of an AR route is disclosed in, for example, PTL 3, or the like. The AR route is a direction in which a driver should go, displayed on a road in a band shape. 
     CITATION LIST 
     Patent Literature 
     PTL 1 
     Japanese Patent Application Laid-Open No. H7-257228 
     PTL 2 
     Japanese Patent Application Laid-Open No. 2018-045103 
     PTL 3 
     Japanese Patent Application Laid-Open No. 2018-140714 
     SUMMARY OF INVENTION 
     Technical Problem 
     In practice, an AR (Augmented Reality) route is created using map information of a navigation system. Specifically, first, the navigation system searches for a route to a destination, and selects coordinates (nodes, links) corresponding to the route among coordinates of roads (nodes, links) included in the map information. Then, a display apparatus forms an AR route on the basis of information of the selected nodes and links and projects the formed AR route on a front windshield as a virtual image. 
     Here, the coordinates of the nodes and the links refer to coordinates of feature points such as, for example, coordinates of intersections and shape interpolating coordinates, in other words, discontinuous coordinates. Because the AR route is formed using discontinuous coordinates in this manner, there are problems that (1) although a route is a linear road, the route looks bent in route display, (2) a route of a curve looks a broken line in route display, or the like. 
     For example, while, in a navigation screen which displays a route on a dedicated small monitor, a bent route, or the like, is less likely to provide a feeling of strangeness to a driver, because the AR route is displayed on a field of view of driving of the driver, an unnatural bent route, or the like, provides a feeling of strangeness to the driver. That is, in display of the AR route, if the AR route does not match a shape of a route on which a subject vehicle is to travel, the driver experiences a great feeling of strangeness. 
     The present disclosure has been made in view of the above-described points, and provides a display system which can display an AR route which matches a shape of a route on which a subject vehicle is to travel without providing a feeling of strangeness. 
     Solution to Problem 
     A display system according to one aspect of the present disclosure is a system for displaying an AR (Augmented Reality) route which is a virtual image so as to be superimposed on a real image seen by a user, the display system including: 
     an AR route former that forms the AR route; and 
     a display that displays the AR route as a virtual image, 
     in which the AR route former determines whether or not a route section is a linear section on a basis of positional relationship of nodes within the route section including three or more nodes, and 
     for the route section which is determined to be the linear section, the AR route former forms a line which connects a start node of the route section with a terminal node of the same, as the AR route. 
     Advantageous Effects of Invention 
     According to the present disclosure, it is possible to display an AR route which matches a shape of a route on which a subject vehicle is to travel without providing a feeling of strangeness. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  illustrates an example where a display apparatus according to an embodiment is mounted on a vehicle; 
         FIG. 2  illustrates an example of a region in which light is projected by the display apparatus in the embodiment; 
         FIG. 3  illustrates an example which a virtual image is displayed so as to be superimposed on foreground; 
         FIG. 4  is a block diagram illustrating a configuration example of a display apparatus; 
         FIGS. 5A to 5C  explain AR route formation in the embodiment; 
         FIG. 6  illustrates a display example of an AR route in a case where line correction processing of the embodiment is not applied; 
         FIG. 7  illustrates a display example of an AR route in a case where the line correction processing of the embodiment is applied; 
         FIG. 8  illustrates a flowchart of flow of the line correction processing of the AR route in the embodiment; 
         FIG. 9  illustrates an example of curve interpolation in the embodiment; 
         FIG. 10  illustrates a display example of an AR route in a case where curve interpolation processing of the embodiment is not applied; 
         FIG. 11  illustrates a display example of an AR route in a case where the curve interpolation processing of the embodiment is applied; 
         FIGS. 12A and 12B  explain display of the AR route which is conventionally performed,  FIG. 12A  illustrates node positions, and  FIG. 12B  illustrates the AR route; 
         FIGS. 13A and 13B  explain display of an AR route in the embodiment,  FIG. 13A  illustrates shifting of the node positions, and  FIG. 13B  illustrates the shifted AR route; and 
         FIG. 14A  illustrates an example where the AR route is not shifted, and  FIG. 14B  illustrates an example where AR route shifting processing of the present embodiment is applied. 
     
    
    
     DESCRIPTION OF EMBODIMENT 
     An embodiment of the present invention will be described below with reference to the accompanying drawings. 
     &lt;1&gt; Schematic Configuration of Display Apparatus 
       FIG. 1  illustrates an example where display apparatus  100  according to an embodiment of the present disclosure is mounted on vehicle  200 . 
     Display apparatus  100  in the present embodiment is embodied as an in-vehicle head-up display (HUD). Display apparatus  100  is attached near an upper face of dashboard  220  of vehicle  200 . 
     Display apparatus  100  projects light on region D 10  within a field of view of a driver, indicated with a dashed-dotted line, in windshield (so-called, front windshield)  210 . While part of the projected light passes through windshield  210 , the other part of the light is reflected by windshield  210 . This reflected light heads for eyes of the driver. The driver perceives the reflected light which has entered the eyes as virtual image Vi which looks like an image of an object located on an opposite side (outside of vehicle  200 ) of windshield  210  against a background of a real object seen through windshield  210 . 
       FIG. 2  illustrates an example of region D 10  which is a region where light is projected by display apparatus  100  in the present embodiment. 
     Region D 10  is located at a lower portion on the driver side of windshield  210 , for example, as indicated as a region enclosed by a dashed line in  FIG. 2 . Display apparatus  100  attached at dashboard  220  projects an image on windshield  210  by projecting light on region D 10  as illustrated in  FIG. 1 . By this means, virtual image Vi which looks like an image of an object located outside of vehicle  200  from the driver is generated. 
     Note that an image projected on windshield  210  can be perceived by the driver in virtual image Vi as if it were located at different distances depending on vertical positions within region D 10 . For example, in the examples in  FIG. 1  and  FIG. 2 , because region D 10  is located at a portion lower than height of the eyes of the driver, an image located at a portion lower in region D 10  can be perceived as if it were an object located closer from the driver in virtual image Vi, while an object located at a portion higher within the image projected on region D 10  can be perceived as if it were an object located farther from the driver in virtual image Vi. Principle of such perception is explained by one type of geometric perspective (vertical perspective). 
       FIG. 3  illustrates an example of a virtual image generated by display apparatus  100  in the present embodiment, and an example where this virtual image is superimposed on scenery ahead of vehicle  200  seen from the driver of vehicle  200  which is traveling. 
       FIG. 3  schematically illustrates part of scenery within a field of view of a driver (not illustrated) who is driving vehicle  200  as a whole. Note that a frame indicated with a dashed line indicating region D 10  in which an image from display apparatus  100  is projected is illustrated for the purpose of illustration of the present embodiment, and neither exists nor is perceived by the driver. Reference numeral  200  indicates a hood which is part of vehicle  200 . Further, an arrow image with reference numeral V 10  indicates an AR (Augmented Reality) route which is an example of virtual image Vi generated by display apparatus  100  and perceived by the driver. 
     As illustrated in  FIG. 3 , AR route V 10  which is a virtual image is displayed so as to be superimposed on scenery actually seen within a field of view of the driver. In practice, AR route V 10  is displayed so as to be superimposed on a road. By this means, the driver is guided to travel on a band-like region indicated by AR route V 10 . 
       FIG. 4  is a block diagram illustrating a configuration example of display apparatus  100 . 
     Display apparatus  100  includes map information acquirer  101 , position detector  102 , radar  103 , vehicle behavior detector  104 , viewpoint detector  105 , image former  110 , display controller  120  and HUD  130 . 
     Map information acquirer  101  acquires map information including information which expresses landforms, road shapes, or the like, with coordinates in an absolute coordinate system. The map information acquired by map information acquirer  101  may be information stored in a map information storage medium mounted on vehicle  200  or may be acquired through communication with an external apparatus. In a case of the present embodiment, map information acquirer  101 , which is a so-called navigation system, acquires a course from a current location to a destination. Map information acquirer  101  outputs the map information and course information to image former  110 . 
     Position detector  102 , which is embodied by a GPS receiver, a gyro scope, a vehicle speed sensor, or the like, detects a current location of subject vehicle  200 . 
     Radar  103  detects whether or not there is an object and a distance to the object by emitting a radio wave or laser light toward a region ahead of subject vehicle  200  and receiving the reflected wave. Note that display apparatus  100  may include other detection apparatuses such as a camera and an infrared sensor in addition to radar  103  to detect an object in a peripheral region. 
     Vehicle behavior detector  104 , which is embodied by a gyro scope, a suspension stroke sensor, a vehicle height sensor, a vehicle speed sensor, an acceleration sensor, or the like, detects a physical amount indicating behavior of the vehicle. 
     Viewpoint detector  105  takes an image of the eyes of the driver with, for example, an infrared camera, and measures coordinates of positions of the eyes of the driver in a vehicle coordinate system from the taken image of the eyes through image processing. The detection result by viewpoint detector  105  is output to display controller  120 . 
     Image former  110  forms an image which becomes a basis of virtual image Vi on the basis of input signals from map information acquirer  101 , position detector  102 , radar  103  and vehicle behavior detector  104 . Image former  110  includes AR route former  111 . AR route former  111  forms an image which becomes a basis of an AR route which is a virtual image on the basis of input signals from map information acquirer  101  and position detector  102 . 
     Display controller  120  displays virtual image Vi in region D 10  of the windshield by controlling a light source, a scanner, a screen driver, or the like, which constitute HUD  130  on the basis of the image formed by image former  110  and viewpoint information. 
     &lt;2&gt; AR Route Formation 
     Before characteristic AR route forming processing according to the present embodiment is described, typical route formation using map information will be described. 
     Note that functions of AR route former  111  which will be described below may be realized by a CPU copying a program stored in a storage apparatus to a RAM, sequentially reading out commands included in the program from the RAM and executing the commands. In other words, the processing of AR route former  111  which will be described below may be realized by a program. 
     AR route former  111  inputs road map data from map information acquirer  101 . In the road map data, a minimum unit indicating a road section is referred to as a link. That is, each road is constituted with a plurality of links set for each predetermined road section. Points which connect the links are referred to as nodes, and each of the nodes has position information (coordinate information). Further, points called shape interpolating points may be set between nodes within a link. Each of the shape interpolating points also has position information (coordinate information) in a similar manner to the nodes. A link shape, that is, a shape of a road is determined by position information of the nodes and the shape interpolating points. 
     The node is an intersection, a branch point, a junction, or the like, and AR route former  111  inputs coordinate information of the intersection, the branch point, the junction, or the like, as information of the nodes. Further, AR route former  111  also inputs coordinate information of the shape interpolating points as described above. 
     Each link is constituted with respective pieces of data such as a link length indicating a length of the link, shape information of the link, coordinates (latitude, longitude) of a start node and a terminal node of the link, road name, a road type, a road width, a road attribute, a one-way attribute, the number of lanes, presence or absence of a right-turn-only or left-turn-only lane, and the number of the right-turn-only or left-turn only lanes as attribute information of the link. 
     AR route forming processing by AR route former  111  of the present embodiment will be described next. Information of the nodes and the links indicating the traveling route of the subject vehicle as described above is input to AR route former  111 . 
     &lt;2-1&gt; Line Correction 
       FIGS. 5A to 5C  explain AR route formation in the present embodiment.  FIGS. 5A to 5C  illustrate nodes N 1  to N 5  within a route section. Therefore, in a conventional AR route forming processing, the AR route which sequentially connects N 1 , N 2 , N 3 , N 4  and N 5  is formed. 
     Meanwhile, in AR route forming processing in the present embodiment, first, it is determined whether or not a section from N 1  to N 5  is a linear section, and, in a case where it is determined that the section is a linear section, line L 0  which connects start node N 1  with terminal node N 5  of the section is formed as the AR route and displayed. On the other hand, in a case where it is determined that the section is not a linear section, dividing processing or curve correction processing which will be described later are performed. 
     The processing will be specifically described. In the AR route forming processing in the present embodiment, first, as illustrated in  FIG. 5A , line L 0  which connects section start node N 1  with section terminal node N 5  within a route section to be subjected to determination on whether or not the section is a linear section is formed. 
     Then, distances h 2 , h 3  and h 4  between line L 0  and other nodes N 2 , N 3  and N 4  included in the route section are calculated. 
     Next, AR route former  111  compares distances h 2 , h 3  and h 4  with a predetermined threshold. In a case where distances h 2 , h 3  and h 4  are all equal to or less than the threshold, AR route former  111  creates an AR route by connecting the section between node N 1  with node N 5  with one line L 0 . On the other hand, in a case where there is a distance greater than the threshold among distances h 2 , h 3  and h 4 , AR route former  111  divides a route section at a node to which the distance is the greatest as a dividing point. In a case of the examples in  FIGS. 5A to 5C , because distance h 3  to node N 3  is the greatest, the route section is divided at node N 3  as the dividing point. 
     Then, as illustrated in  FIG. 5B , processing of determining whether or not the section is a linear section is repeated in a similar manner as described above using the dividing point as an end point and a start point of the section. Specifically, line L 1  which connects section start node N 1  with section terminal node N 3  is formed within the route section. In a similar manner, line L 2  which connects section start node N 3  with section terminal node N 5  is formed within the route section. Then, distance h 2  between line L 1  and another node N 2  included within the route section is calculated. In a similar manner, distance h 4  between line L 2  and another node N 4  included in the route section is calculated. Then, distance h 2  is compared with the threshold. In a similar manner, distance h 4  is compared with the threshold. In an example of the drawing, because distance h 2  is smaller than the threshold, as illustrated in  FIG. 5C , an AR route is created by connecting a section between node N 1  and node N 3  with one line L. In a similar manner, because distance h 4  is smaller than the threshold, as illustrated in  FIG. 5C , an AR route is created by connecting a section between node N 3  and node N 5  with one line L 2 . 
     In short, line correction processing in the present embodiment is processing for creating a line while excluding (ignoring) nodes which do not largely deviate from a line connecting a start node with a terminal node of a section. By this means, it is possible to prevent an AR route from being unnaturally bent due to a way of setting of coordinates of the nodes. For example, it is possible to prevent inconvenience that an AR route is slightly bent for each intersection due to the coordinate of the node being set at a coordinate of the center of the intersection, although the road is actually a linear road. 
       FIG. 6  illustrates a display example of the AR route in a case where the line correction processing of the present embodiment is not applied. It can be seen from this drawing that the AR route is slightly bent at the intersection although the road is a linear road.  FIG. 7  illustrates a display example of the AR route in a case where the line correction processing of the present embodiment is applied. It can be seen from this drawing that a bent portion of the AR route at the intersection disappears. 
       FIG. 8  illustrates a flowchart of flow of the line correction processing of the AR route in the present embodiment. 
     AR route former  111  first calculates distance h between a line connecting the start node with the terminal node and another node included in the section in step S 1 . That is, AR route former  111  calculates distances h 2 , h 3  and h 4  between line L 0  connecting section start node N 1  with section terminal node N 5  and other nodes N 2 , N 3  and N 4  included in the section in the example in  FIG. 5A . 
     AR route former  111  calculates whether or not all distances h 2 , h 3  and h 4  are equal to or less than a threshold in the subsequent step S 2 . In a case where a positive result is obtained in step S 2  (step S 2 : Yes), the processing transitions to step S 3 , and the section is determined to be a linear section, and an AR route is formed. In the example in  FIG. 5A , line L 0  is set as the AR route. 
     Meanwhile, in a case where a negative result is obtained in step S 2  (step S 2 : No), the processing transitions to step S 4 , and the section is divided at a node to which distance h is the greatest as a dividing point. That is, in the example in  FIG. 5B , the route section is divided at node N 3  as the dividing point. The processing of AR route former  111  returns to step S 1  again after the processing in step S 4 . This processing in step S 1  corresponds to the processing of calculating distances h 2  and h 4  in the example in  FIG. 5B . 
     In this manner, AR route former  111  divides the section until there is no longer a node to which the distance is equal to or greater than the threshold by recursively repeating the processing of step S 1 -S 2 -S 4 -S 1  until a positive result can be obtained in step S 2 . Then, when such a node no longer exists, the section is determined to be a linear section, and the processing in step S 3  is performed to form a liner AR route within the linear section. 
     &lt;2-2&gt; Curve Interpolation 
     AR route former  111  in the present embodiment performs curve interpolation on the route section which is determined to be a non-linear section. 
     For example, curve interpolation as illustrated in  FIG. 9  is performed on a non-linear section subjected to the line correction (which can be also referred to as smoothing of a line) as described in section &lt;2-1&gt;. In the example in  FIG. 9 , because line L 1  and line L 2  are connected while being bent via node N 3  which is the dividing point, a section from N 1 -N 3 -N 5  is not a linear section. In practice, in most every case, the section from N 1 -N 3 -N 5  is not a bent road, but a curve. In view of this, AR route former  111  forms curve L 10  by performing curve interpolation on the section from N 1 -N 3 -N 5  and outputs this curve L 10  as the AR route. 
     At this time, AR route former  111  performs curve interpolation using nodes included in the section as control points. In the example in  FIG. 9 , curve L 10  is formed by curve interpolation being performed using nodes N 1 , N 3  and N 5  as control points. 
     Here, the nodes are not always arranged so as to make a clear curve, and there is a case where a curve shape having distortion is made if curve interpolation is performed so that the curve passes through all nodes. In view of this, in the present embodiment, curve L 10  without distortion is formed by interpolation being performed using a B-spline curve. However, the curve interpolation is not limited to interpolation using a B-spline curve. 
     Note that, while a case has been described here where curve interpolation is performed on a section which is not a linear section after the line correction as described in section &lt;2-1&gt; has been performed, the present invention is not limited to this, and, in short, it is only necessary to perform curve interpolation on the route section which is determined to be a non-linear section using nodes included in the section as the control points and output a curve subjected to the curve interpolation as the AR route. 
       FIG. 10  illustrates a display example of the AR route in a case where the curve interpolation processing of the present embodiment is not applied. It can be seen from this drawing that the AR route becomes a broken line although an actual road is curved.  FIG. 11  illustrates a display example of the AR route in a case where the curve interpolation processing of the present embodiment is applied. It can be seen from this drawing that the AR route having a curved shape along the curve can be displayed. 
     &lt;2-3&gt; Processing of Shifting AR Route on the Basis of Lane Information 
     As described above, the AR route is created on the basis of the nodes and the links included in the road map data. However, because the coordinate information included in the nodes and the links are often coordinates of the centers of the roads, if the AR route is formed using the information as it is, there is a case where an AR route which provides a feeling of strangeness is displayed. Particularly, an AR route which provides a feeling of strangeness is highly likely to be displayed at positions such as an intersection and a branch point, where a plurality of roads intersect. 
     In view of this, in the present embodiment, the AR route is formed by shifting a coordinate of the node included in the road map data to a lane on which the subject vehicle is to travel on the basis of the lane information. By this means, on the basis of the lane information, it becomes possible to display an AR route which does not provide a feeling of strangeness, shifted on the side of the lane on which the subject vehicle travels. For comparison, because the AR route is formed by connecting the nodes, shifting the coordinate of the node is equivalent to shifting the AR route. Therefore, in the following description, it is possible to read shifting the coordinate of the node as shifting the AR route, inversely, it is possible to read shifting the AR route as shifting the coordinate of the node. 
       FIGS. 12A and 12B  explain conventional display of an AR route. As illustrated in  FIG. 12A , a case is assumed where the subject vehicle is travelling on a road which has one lane each way and which has a center line, and turns right at an intersection ahead. At this time, coordinates of nodes N 1  to N 4  are coordinates on the center line. 
       FIG. 12B  illustrates the AR route formed and displayed on the basis of nodes N 1  to N 4  in  FIG. 12A . As can be seen from  FIG. 12B , because, in the conventional AR route, the start point is set so as to match a traveling position of the subject vehicle, while a portion ahead of the subject vehicle is displayed without providing a feeling of strangeness, after the subject vehicle passes through an intersection, the AR route is on a center line. That is, the AR route is displaced in the center line direction from a lane on which the subject vehicle is to actually travel. 
       FIGS. 13A and 13B  explain display of the AR route in the present embodiment. In the present embodiment, as illustrated in  FIG. 13A , nodes N 1 ′, N 2 ′, N 3 ′ and N 4 ′ are calculated by coordinates of nodes N 1 , N 2 , N 3  and N 4  on the center line being shifted to the lane on which the subject vehicle is to travel, and the AR route is formed and displayed using nodes N 1 ′, N 2 ′, N 3 ′ and N 4 ′. 
       FIG. 13B  illustrates the AR route formed and displayed on the basis of nodes N 1 ′, N 2 ′, N 3 ′ and N 4 ′ in  FIG. 13A . As can be seen from  FIG. 13B , the AR route in the present embodiment is displayed on the lane on which the subject vehicle is to travel even after the subject vehicle passes through the intersection. As a result, it is possible to display the AR route without providing a feeling of strangeness. 
     Here, a specific example of shifting of the AR route according to the present embodiment will be described here. 
     In a case where the road has three lanes each way and a lane on which the subject vehicle is to travel is the leftmost lane, the node positions are shifted on the lane of the subject vehicle by a “lane width (for example, 3.25 m)×(the number of lanes (in this example, 3)-0.5)”. This processing is processing to address a situation where the nodes are set on the center line. 
     In this manner, in the AR route shifting processing of the present embodiment, a node set at the center of the road is shifted on the lane on which the subject vehicle is to travel. In the present embodiment, the AR route is shifted to the center of the lane on which the subject vehicle is to travel. 
     Then, effects by the AR route shifting processing according to the present embodiment will be described using  FIGS. 14A and 14B . 
       FIGS. 14A and 14B  illustrate display of the AR route in a case where the subject vehicle turns left at an intersection ahead.  FIG. 14A  illustrates an example where the AR route is not shifted, and  FIG. 14B  illustrates an example where the AR route shifting processing of the present embodiment is applied. As can be clear through comparison between these drawings, while the AR route in  FIG. 14A  is displayed near the center of the road on which the subject vehicle is not to travel after the subject vehicle passes through the intersection, the AR route in  FIG. 14B  is displayed on the lane on which the subject vehicle is to travel even after the subject vehicle passes through the intersection without a feeling of strangeness being provided. 
     In this manner, by performing the AR route shifting processing of the present embodiment, even if the node position at the intersection is displaced to a left side or right side from an extension of the traveling lane, it is possible to display the AR route along the lane on which the subject vehicle is to travel without providing a feeling of strangeness. 
     &lt;3&gt; Conclusion 
     As described above, according to the present embodiment, as described in section &lt;2-1&gt;, whether or not the route section is a linear section is determined on the basis of positional relationship of the nodes within the route section including three or more nodes, and a line connecting a start node with a terminal node of the route section is formed and displayed as the AR route for the route section which is determined to be a linear section, so that it is possible to display the AR route which matches the shape of the route on which the subject vehicle is to travel without providing a feeling of strangeness while resolving inconvenience that the AR route looks bent although the road is a linear road. 
     Further, as described in section &lt;2-2&gt;, for the route section which is determined to be a non-linear section, by forming the AR route having a shape which is subjected to curve interpolation using the nodes included in the section as control points, it is possible to display the AR route which matches the shape of the route on which the subject vehicle is to travel without providing a feeling of strangeness. 
     Particularly, even a slight difference in orientation between links which seem linear roads when seen from above looks a large angle in display of the route like display of the AR route, which is obliquely seen. By performing the line correction and the curve interpolation in the above-described embodiment, it is possible to effectively resolve this problem. 
     While, in the above-described embodiment, a case has been described where the display apparatus of the present disclosure is applied to an in-vehicle HUD, the present disclosure is not limited to this, and the display apparatus of the present disclosure can be widely applied to display systems and apparatuses which display the AR route which is a virtual image so as to be superimposed on a real image which is seen by the user, in short. 
     While various embodiments have been described herein above, it is to be appreciated that various changes in form and detail may be made without departing from the spirit and scope of the invention(s) presently or hereafter claimed. 
     INCORPORATION BY REFERENCE 
     This application is entitled and claims the benefit of Japanese Patent Application No. 2019-061463, filed on Mar. 27, 2019, the disclosure of which including the specification, drawings and abstract is incorporated herein by reference in its entirety. 
     INDUSTRIAL APPLICABILITY 
     The display system of the present invention is suitable for, for example, a system including an in-vehicle HUD. 
     REFERENCE SIGNS LIST 
     
         
           100  Display apparatus 
           101  Map information acquirer 
           102  Position detector 
           103  Radar 
           104  Vehicle behavior detector 
           105  Viewpoint detector 
           110  Image former 
           111  AR route former 
           120  Display controller 
           130  HUD (Head-Up Display) 
           200  Vehicle 
           210  Windshield 
           220  Dashboard 
         N 1 , N 2 , N 3 , N 4 , N 5  Node 
         h 2 , h 3 , h 4  Distance 
         L 0 , L 1 , L 2  Line 
         L 10  Curve 
         Vi Virtual image