JP2013206239A - Map image display system, map image display device, map image display method, and computer program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image display system that prevents the occurrence of large deviation between a shadow that is actually made and a shadow drawn on a map image caused by drawing a shadow made by a feature on a map on the map image, an image display device, an image display method, and a computer program.SOLUTION: A map image display system is configured to acquire illuminance (current illuminance) of light that is actually radiated around a liquid crystal display 15, and draw a shadow made by a feature on a map on a map image when the current illuminance is equal to or more than a predetermined reference threshold.

Description

  The present invention relates to a map image display system, a map image display device, a map image display method, and a computer program for displaying a map image.

  2. Description of the Related Art In recent years, a navigation device is often mounted on a vehicle that provides vehicle travel guidance so that a driver can easily arrive at a desired destination. Here, the navigation device detects the current position of the vehicle by a GPS receiver or the like, acquires map data corresponding to the current position through a recording medium such as a DVD-ROM or HDD or a network, and stores it in the image display device. It is a device capable of displaying. In recent years, some mobile phones, smart phones, PDAs (Personal Digital Assistants), personal computers, and the like have the same map image display function as the navigation device.

  Further, conventionally, when a map image is displayed on the navigation device or the like, a shadow caused by a feature (such as a building) on the map is displayed in order to bring the display of the map image closer to the actual situation around the vehicle. A technique for drawing on an image has been proposed. For example, in Japanese Patent Application Laid-Open No. 2006-126445, the position of the sun at the current time is calculated, and based on the positional relationship between the sun and the feature on the map, the color or range of the shadow caused by the feature is specified, A technique for drawing a shadow on a map image is described.

JP 2006-126445 A (page 5-7, FIG. 1)

  However, in addition to the current date and time, various factors such as weather influence how shadows are generated on features. Therefore, in the configuration in which the color and range of the shadow caused by the feature is specified based on the current date and time as in Patent Document 1 described above, there is a large deviation between the shadow that actually occurs and the shadow that is drawn on the map image. There was a case.

  The present invention has been made to solve the above-described conventional problems, and an image display system and an image display which prevent a large shift between an actually generated shadow and a shadow drawn on a map image. An object is to provide an apparatus, an image display method, and a computer program.

To achieve the above object, a map image display system (1) according to claim 1 of the present application displays a map image display means (13) for displaying a map image (51) including a feature (65) on an image display device (15). ), Current illuminance acquisition means (13) for acquiring the illuminance of the light radiated to the periphery of the image display device as the current illuminance, and shadows generated by the features when the current illuminance is equal to or higher than a reference threshold ( 66) and a shadow drawing means (13) for drawing in the map image.
The “light irradiated to the periphery of the image display device” includes light irradiated within a predetermined distance of the image display device and light irradiated to the image display device itself.
In addition to buildings, “features” include structures such as overpasses and traffic lights, and natural objects such as trees.

Further, the map image display system (1) according to claim 2 is the map image display system according to claim 1, wherein the current illuminance acquisition means (13) moves together with the image display device (15). The illuminance of the light irradiated to (60) is acquired as the current illuminance.
The “moving body” includes a pedestrian and a two-wheeled vehicle in addition to the vehicle.

  Further, the map image display system (1) according to claim 3 is the map image display system according to claim 2, wherein the current illuminance acquisition means (13) is configured to transmit light radiated to the moving body (60). Illuminance is acquired for each of a plurality of directions, and the shadow drawing means (13) draws the shadow when the current illuminance in one or more of the plurality of directions is equal to or greater than the reference threshold. It is characterized by that.

  The map image display system (1) according to claim 4 is the map image display system according to claim 3, wherein the shadow drawing means (13) is an illuminance equal to or higher than the reference threshold value in the plurality of directions. A shadow (66) generated by the feature (65) when light is irradiated from the direction in which the image is acquired is drawn in the map image.

  Further, the map image display system (1) according to claim 5 is the map image display system according to any one of claims 1 to 4, wherein the shadow drawing means (13) corresponds to the current illuminance. The shadow (66) is drawn with density.

  Further, the map image display system (1) according to claim 6 is the map image display system according to any one of claims 1 to 5, wherein the shadow drawing means (13) is configured such that the current illuminance is the reference. When the current illuminance becomes less than the reference threshold when the current illuminance is less than the reference threshold, the shadow (66) is continuously drawn until a predetermined time elapses.

  A map image display system (1) according to claim 7 is the map image display system according to any one of claims 1 to 6, wherein a date and time acquisition means (13) for acquiring the current date and time, Corresponding illuminance acquisition means (13) for acquiring the illuminance of light that is predicted to irradiate around the image display device (15) at the date and time, and the shadow drawing means (13) When the current illuminance is higher than the corresponding illuminance by an allowable threshold or more, the shadow is not drawn even when the current illuminance is more than the reference threshold.

  Further, the map image display system (1) according to claim 8 is the map image display system according to claim 1, wherein the current illuminance acquisition means (13) is light applied to the image display device (15). Is obtained as the current illuminance.

  A map image display device (1) according to claim 9 is a map image display device that displays a map image (51) including a feature (65), and is irradiated to the periphery of the map image display device. Current illuminance acquisition means (13) that acquires the illuminance of light as the current illuminance, and a shadow drawing means (13) that draws a shadow caused by the feature in the map image when the current illuminance is greater than or equal to a reference threshold value. It is characterized by having.

  According to a tenth aspect of the present invention, there is provided a map image display method for displaying a map image (51) including a feature (65) in an image display device (15), and irradiating the periphery of the image display device. A current illuminance acquisition step of acquiring the illuminance of light as current illuminance, and a shadow drawing step of drawing a shadow (66) caused by the feature in the map image when the current illuminance is equal to or greater than a reference threshold; It is characterized by having.

  Furthermore, the computer program according to claim 11 irradiates a computer with a map image display function for displaying a map image (51) including the feature (65) on the image display device (15) and the periphery of the image display device. A current illuminance acquisition function for acquiring the illuminance of the generated light as the current illuminance, and a shadow drawing function for drawing a shadow (66) generated by the feature in the map image when the current illuminance is greater than or equal to a reference threshold; Are executed by a processor.

  According to the map image display system according to claim 1 having the above-described configuration, when the illuminance of light radiated to the periphery of the image display device is equal to or higher than a predetermined reference threshold, a shadow caused by a feature on the map is displayed. Since the image is drawn on the map image, it is possible to prevent a large shift between the shadow actually generated and the shadow drawn on the map image. For example, it is possible to prevent a shadow from being drawn on the map image even though no shadow is actually generated, or to prevent a shadow from being drawn on the map image even though a shadow is actually generated. As a result, the display of the map image can be brought close to the actual situation around the user, and the uncomfortable feeling caused by the difference between the displayed map image and the actual landscape visually recognized by the user can be reduced.

  According to the map image display system of claim 2, since the illuminance of the light irradiated to the moving body moving together with the image display device is acquired as the current illuminance, the illuminance of the light is detected by the image display device itself. Even if no device is installed, it is possible to detect the irradiation state of light around the user that affects the density and range of the shadow caused by the feature.

  According to the map image display system according to claim 3, when the illuminance of the light irradiated to the moving body is obtained for each of a plurality of directions, and the current illuminance in any one direction is greater than or equal to the reference threshold value. Since the shadow caused by the feature is drawn, it is possible to detect the correct current illuminance even when the light source is in an orientation other than directly above the moving body. Therefore, it is possible to accurately specify the shadow situation actually caused by the feature.

  Further, according to the map image display system of claim 4, since the shadow caused by the feature is drawn in the map image when the light is irradiated from the direction in which the illuminance equal to or higher than the reference threshold is acquired, the movement is performed. The direction of the light source with respect to the body can be accurately specified, the range of the shadow actually caused by the feature can be accurately specified and reproduced on the map image.

  Further, according to the map image display system of claim 5, since the shadow is drawn at a density according to the current illuminance, the shadow can be drawn on the map image at a density close to the actually occurring shadow. It becomes possible. As a result, the display of the map image can be brought close to the actual situation around the user, and the uncomfortable feeling caused by the difference between the displayed map image and the actual landscape visually recognized by the user can be reduced.

  Further, according to the map image display system of claim 6, when the current illuminance falls from the reference threshold value to less than the reference threshold value, the shadow is not reflected until a predetermined time elapses after the current illuminance becomes less than the reference threshold value. Will continue to draw shadows on the map image even when entering a tunnel, etc., or entering the shadow of a building and the current illuminance temporarily falls below the reference threshold. It becomes possible to do. Therefore, it is possible to prevent the shadow from being drawn on the map image even though the shadow is actually generated.

  According to the map image display system of claim 7, the illuminance of light predicted to be irradiated around the image display device at the current date and time is acquired as the corresponding illuminance, and the current illuminance is less than the corresponding illuminance. If it is higher than the allowable threshold, no shadow will be drawn even if the current illuminance is higher than the reference threshold. It is possible to prevent a shadow from being erroneously drawn on a map image when the surroundings become bright or when the headlight of another vehicle is irradiated. Therefore, it is possible to prevent the shadow from being drawn on the map image even though no shadow is actually generated.

  According to the map image display system of claim 8, since the illuminance of the light irradiated to the image display device is acquired as the current illuminance, when the device for detecting the illuminance of light is installed in the image display device itself Even so, it becomes possible to detect the irradiation state of the light around the user that affects the density and range of the shadow caused by the feature.

  According to the map image display device of claim 9, when the illuminance of the light irradiated to the map image display device is equal to or higher than a predetermined reference threshold, a shadow caused by the feature on the map is displayed on the map image. Since the drawing is performed, it is possible to prevent a large shift between the shadow actually generated and the shadow drawn on the map image. For example, it is possible to prevent a shadow from being drawn on the map image even though no shadow is actually generated, or to prevent a shadow from being drawn on the map image even though a shadow is actually generated. As a result, the display of the map image can be brought close to the actual situation around the user, and the uncomfortable feeling caused by the difference between the displayed map image and the actual landscape visually recognized by the user can be reduced.

  According to the map image display method of claim 10, when the illuminance of light radiated to the periphery of the image display device is equal to or higher than a predetermined reference threshold, a shadow caused by a feature on the map is displayed on the map image. Therefore, it is possible to prevent a large shift between the shadow actually generated and the shadow drawn on the map image. For example, it is possible to prevent a shadow from being drawn on the map image even though no shadow is actually generated, or to prevent a shadow from being drawn on the map image even though a shadow is actually generated. As a result, the display of the map image can be brought close to the actual situation around the user, and the uncomfortable feeling caused by the difference between the displayed map image and the actual landscape visually recognized by the user can be reduced.

  Furthermore, according to the computer program according to claim 11, when the illuminance of light radiated to the periphery of the image display device is equal to or higher than a predetermined reference threshold, a shadow caused by the feature on the map is drawn on the map image. Therefore, it is possible to prevent a large deviation from occurring between the shadow actually generated and the shadow drawn on the map image. For example, it is possible to prevent a shadow from being drawn on the map image even though no shadow is actually generated, or to prevent a shadow from being drawn on the map image even though a shadow is actually generated. As a result, the display of the map image can be brought close to the actual situation around the user, and the uncomfortable feeling caused by the difference between the displayed map image and the actual landscape visually recognized by the user can be reduced.

It is the block diagram which showed the navigation apparatus which concerns on this embodiment. It is the figure which showed the illumination intensity correspondence table. It is the figure which showed the driving guidance screen displayed on a liquid crystal display. It is the figure which showed the illumination intensity sensor installed in the vehicle. It is a flowchart of the map image display processing program which concerns on this embodiment. It is the figure which showed the intensity | strength of the light of the light source estimated when the difference of the present illumination intensity for every direction is large. It is the figure which showed the light intensity of the light source estimated when the difference of the present illumination intensity for every direction is small. It is a flowchart of the shadow drawing process program which concerns on this embodiment. It is the figure which showed the drawing aspect of the shadow with respect to a map image.

  Hereinafter, a map image display system and a map image display device according to the present invention will be described in detail with reference to the drawings based on an embodiment in which the map image display device is embodied in a navigation device. First, a schematic configuration of the navigation device 1 according to the present embodiment will be described with reference to FIG. FIG. 1 is a block diagram showing a navigation device 1 according to this embodiment.

  As shown in FIG. 1, the navigation device 1 according to the present embodiment includes a current position detection unit 11 that detects a current position of a vehicle on which the navigation device 1 is mounted, a data recording unit 12 that records various data, The navigation ECU 13 that performs various arithmetic processes based on the input information, the operation unit 14 that receives operations from the user, the liquid crystal display 15 that displays a map image around the vehicle to the user, and route guidance A communication module 18 that performs communication between a speaker 16 that outputs voice guidance, a DVD drive 17 that reads a DVD as a storage medium, and an information center such as a probe center or a VICS (registered trademark: Vehicle Information and Communication System) center. And is composed of. In addition, the navigation device 1 is connected to illuminance sensors 19A to 19D installed at a total of four locations on the outer wall of the vehicle on which the navigation device 1 is mounted via an in-vehicle network such as CAN.

Below, each component which comprises the navigation apparatus 1 is demonstrated in order.
The current position detection unit 11 includes a GPS 21, a vehicle speed sensor 22, a steering sensor 23, a gyro sensor 24, and the like, and can detect the current vehicle position, direction, vehicle traveling speed, current time, and the like. . Here, in particular, the vehicle speed sensor 22 is a sensor for detecting a moving distance and a vehicle speed of the vehicle, generates a pulse according to the rotation of the driving wheel of the vehicle, and outputs a pulse signal to the navigation ECU 13. And navigation ECU13 calculates the rotational speed and moving distance of a driving wheel by counting the generated pulse. Note that the navigation device 1 does not have to include all the four types of sensors, and the navigation device 1 may include only one or more types of sensors.

  The data recording unit 12 reads an external storage device and a hard disk (not shown) as a recording medium, a map information DB 31 recorded on the hard disk, an illuminance correspondence table 32, a predetermined program, and the like, and stores predetermined data on the hard disk. And a recording head (not shown) which is a driver for writing. The data recording unit 12 may be configured by a memory card, an optical disk such as a CD or a DVD, instead of the hard disk. Further, an external server may have the data recording unit 12, and the navigation device 1 may acquire data from the server via communication.

  Here, the map information DB 31 includes, for example, link data relating to roads (links), node data relating to node points, point data relating to points such as facilities, map display data for displaying maps, intersection data relating to each intersection, and routes. It is a storage means in which search data for searching, search data for searching for points, and the like are stored.

In addition, the illuminance correspondence table 32 is predicted to be irradiated on the date and the vicinity of the liquid crystal display 15 (more specifically, the outer wall of the vehicle on which the navigation device 1 is installed) when the vehicle travels outdoors at the date and time. Is a table in which stored illuminance (hereinafter referred to as appropriate illuminance) is stored in association with each other. FIG. 2 shows an example of the illuminance correspondence table 32.
As shown in FIG. 2, the illuminance correspondence table 32 is divided into a predetermined range of date and time, and corresponding illuminance is stored in association with each division. For example, in the example illustrated in FIG. 2, “35000 lx (lux)” is associated with 5:00 to 10:00 as the corresponding illuminance between April 1 and May 30. That is, in the time zone from 5:00 to 10:00 from April 1 to May 30, it is predicted that 35,000 lx of light will be irradiated to the periphery of the liquid crystal display 15 when the vehicle travels outdoors. The In addition to the date and time, the illuminance correspondence table 32 may be associated with illuminance corresponding to each weather (for example, sunny, cloudy, rainy) or each region (for example, Hokkaido, Honshu, Shikoku, Kyushu, Okinawa).
Then, the navigation ECU 13 specifies the corresponding illuminance corresponding to the current date and time from the illuminance correspondence table 32 as described later. Then, based on the difference between the actual illuminance detected by the illuminance sensors 19A to 19D and the corresponding illuminance, a display mode (more specifically, the color of the color and brightness when the map image is displayed on the liquid crystal display 15 is displayed. Attributes and the brightness of the backlight), and the shadows caused by the features on the map (for example, buildings, trees, traffic lights, etc.) are drawn on the map image. Note that color attributes include hue, saturation, brightness, and contrast, and are specified by RGB values.

  On the other hand, the navigation ECU (Electronic Control Unit) 13 is an electronic control unit that controls the entire navigation device 1. The CPU 41 as an arithmetic device and a control device, and a working memory when the CPU 41 performs various arithmetic processes. In addition to the RAM 42 storing the route data when the route is searched and the currently set display mode (RGB value, backlight luminance) of the liquid crystal display 15, a control program, etc. And an internal storage device such as a flash memory 44 for storing a program read from the ROM 43 and a ROM 43 in which a map image display processing program (see FIG. 5) and a shadow drawing processing program (see FIG. 8) are recorded. The navigation ECU 13 constitutes various means as processing algorithms. For example, the map image display means displays a map image including features on the liquid crystal display 15. The current illuminance acquisition unit acquires the illuminance of the light applied to the periphery of the liquid crystal display 15 as the current illuminance. The shadow drawing means draws a shadow caused by the feature in the map image when the current illuminance is equal to or higher than the reference threshold value. The date and time acquisition unit acquires the current date and time. The corresponding illuminance acquisition means acquires the illuminance of light predicted to be irradiated around the liquid crystal display 15 at the current date and time as the corresponding illuminance.

  The operation unit 14 is operated when inputting a departure point as a travel start point and a destination as a travel end point, and includes a plurality of operation switches (not shown) such as various keys and buttons. Then, the navigation ECU 13 performs control to execute various corresponding operations based on switch signals output by pressing the switches. The operation unit 14 can also be configured by a touch panel provided on the front surface of the liquid crystal display 15. Moreover, it can also be comprised with a microphone and a speech recognition apparatus.

  In addition, the liquid crystal display 15 includes a travel guidance screen for guiding vehicle travel, a facility search screen for performing facility searches, a menu screen, traffic information, operation guidance, operation menus, key guidance, from the current position to the destination. Guide route, guide information along the guide route, news, weather forecast, time, mail, TV program, etc. are displayed. Here, FIG. 3 is a diagram showing an example of a travel guidance screen 50 displayed on the liquid crystal display 15 while the vehicle is traveling.

  As shown in FIG. 3, the travel guidance screen 50 displayed on the liquid crystal display 15 includes a map image 51 around the current position of the vehicle, and a vehicle position mark 52 indicating the current position of the vehicle matched on the map. The center cursor 53 for specifying the center position of the display target area of the map image, the guide route 54 currently set in the navigation device 1 (displayed only when the guide route is set), and a predetermined function in the navigation device 1 Various buttons 55 to 59 for selection to execute are displayed. The user can grasp facility information around the current vehicle, road shape (including a guidance route when a guidance route is set), and the like by referring to the travel guidance screen 50. When the detail button 55 is touched on and selected, the scale of the map can be changed to a larger scale. Further, when the display change button 56 is touched on and selected, the display mode (bird's eye view, plan view, nose up, north up, etc.) of the map image 51 can be changed. When the destination set button 57 is touched on and selected, the point indicated by the central cursor 53 can be set as the destination. When the location registration button 58 is touched on and selected, the location indicated by the central cursor 53 can be registered in the navigation device 1 as a registration location. When the wide area button 59 is touched on and selected, the scale of the map can be changed to a smaller scale.

  The liquid crystal display 15 has a backlight 45 inside, and illuminates the display area of the liquid crystal display 15 with light emitted from the backlight 45. In the navigation device 1, a display mode (more specifically, a color attribute and a luminance of the backlight 45) relating to the color and brightness when the map image or the like is displayed on the liquid crystal display 15 is set in advance. Stored in the RAM 42 or the like. Note that color attributes include hue, saturation, brightness, and contrast, and are specified by RGB values. When a map image or the like is displayed on the liquid crystal display 15, the display mode of the image currently set in the navigation device 1 is read from the RAM 42 or the like, and the map image or the like is displayed according to the read image display mode. The setting of the display mode can be arbitrarily changed from the standard setting at the time of factory shipment by a user operation. Further, as will be described later, when the difference between the actual illuminance detected by the illuminance sensors 19A to 19D and the corresponding illuminance is equal to or greater than the threshold value, processing for temporarily changing the display mode of the image from the set state is also performed. .

  The speaker 16 outputs voice guidance for guiding traveling along the guidance route based on an instruction from the navigation ECU 13 and traffic information guidance. It is also used when outputting information related to the found facility when the facility search is performed.

  The DVD drive 17 is a drive that can read data recorded on a recording medium such as a DVD or a CD. Based on the read data, music and video are reproduced, the map information DB 31 is updated, and the like. In addition, it is good also as a structure provided with HDD and a memory card reader instead of the DVD drive 17. FIG.

  The communication module 18 is a communication for receiving traffic information composed of information such as traffic jam information, regulation information, and traffic accident information transmitted from a traffic information center such as a VICS (registered trademark) center or a probe center. For example, a mobile phone or DCM is applicable.

  Further, as shown in FIG. 4, the illuminance sensors 19 </ b> A to 19 </ b> D are installed on the outer wall of the vehicle 60 on which the navigation device 1 is installed, and detect the illuminance of light irradiated on the outer wall of the vehicle 60. In particular, the illuminance sensor 19A is installed near the front nozzle of the vehicle and detects the illuminance of light emitted from the front of the vehicle. The illuminance sensor 19B is installed near the rear bumper of the vehicle and detects the illuminance of light emitted from the rear of the vehicle. The illuminance sensor 19C is installed near the door mirror on the left side surface of the vehicle, and detects the illuminance of light emitted from the left side of the vehicle. The illuminance sensor 19D is installed near the door mirror on the right side surface of the vehicle, and detects the illuminance of light emitted from the right side of the vehicle. In addition, you may install apparatuses other than the illumination intensity sensors 19A-19D as a means to detect illumination intensity. For example, it is good also as a structure which installs a camera instead of the illumination intensity sensors 19A-19D.

  Next, a map image display processing program executed by the navigation ECU 13 in the navigation device 1 having the above configuration will be described with reference to FIG. FIG. 5 is a flowchart of the map image display processing program according to this embodiment. Here, the map image display processing program is executed after the ACC of the vehicle is turned on, displays a map image around the vehicle on the liquid crystal display 15, and displays the map displayed on the liquid crystal display 15 in a necessary situation. It is a program for changing the display mode of an image. Note that the programs shown in the flowcharts of FIGS. 5 and 8 below are stored in the RAM 42 and the ROM 43 provided in the navigation device 1 and are executed by the CPU 41.

  First, in step (hereinafter abbreviated as S) 1 in the map image display processing program, the CPU 41 acquires the display mode of the map image currently set in the navigation device 1. Here, the navigation device 1 has a display mode (more specifically, the color attribute and the luminance of the backlight 45) related to the color and brightness when displaying various images such as a map image on the liquid crystal display 15. It is set in advance and stored in the RAM 42 or the like. Note that color attributes include hue, saturation, brightness, and contrast, and are specified by RGB values. In S <b> 1, the CPU 41 acquires the image display mode currently set in the navigation device 1 by reading it from the RAM 42 or the like.

  Next, in S <b> 2, the CPU 41 displays a travel guidance screen 50 (see FIG. 3) including the map image 51 on the liquid crystal display 15 based on the display mode of the image acquired in S <b> 1.

  Subsequently, in S3, the CPU 41 actually irradiates the periphery of the liquid crystal display 15 (more specifically, the outer wall of the vehicle 60 in which the navigation device 1 is installed) based on the detection results of the illuminance sensors 19A to 19D. The illuminance of the current light (hereinafter, the current illuminance) is detected. As described above, the illuminance sensors 19A to 19D acquire the illuminance of light irradiated to the vehicle in every four directions, front, rear, left, and right (see FIG. 4).

  Thereafter, in S4, the CPU 41 acquires the current date and time. The current date and time may be acquired by the GPS 21, may be acquired by communicating with an external server via the communication module 18, or may be acquired by a timer provided in the navigation device 1. good.

  Next, in S5, based on the current date and time and the illuminance correspondence table 32 (FIG. 2) acquired in S4, the CPU 41 is arranged around the liquid crystal display 15 (more specifically, when the vehicle travels outdoors at the current date and time). Specifically, the corresponding illuminance predicted to be irradiated on the outer wall of the vehicle on which the navigation device 1 is installed is specified.

Subsequently, in S6, the CPU 41 determines whether or not the difference between the current illuminance detected in S3 and the corresponding illuminance specified in S5 is equal to or greater than a predetermined threshold. In addition, when the value of the present illuminance detected by the illuminance sensors 19A to 19D is different for each direction, it is desirable to use the highest current illuminance as the determination target in S6. However, an average value in four directions may be used.
In addition, the threshold value that is the determination criterion in S6 is, for example, 10000 lx, and is stored in the RAM 42 or the like. The threshold value may be a fixed value or may be changed as appropriate according to the surrounding conditions (for example, 30000 lx in the daytime and 5000 lx in the nighttime). Here, the situation where the current illuminance and the corresponding illuminance differ greatly include, for example, when the surroundings of the vehicle suddenly become dark when the surroundings of the vehicle are bright, such as in the daytime in summer, or when the surroundings suddenly become dark. There are cases where the surroundings suddenly become bright when the vehicle approaches a streetlight or a store in a dark situation such as at night.

  If it is determined that the difference between the current illuminance and the corresponding illuminance is greater than or equal to a predetermined threshold (S6: YES), it is recognized that the display mode of the map image should be changed from the current setting state, and S7 Migrate to On the other hand, if it is determined that the difference between the current illuminance and the corresponding illuminance is less than a predetermined threshold (S6: NO), it is determined that there is no need to change the display mode of the map image from the current setting state. Then, the map image display processing program ends.

  In S7, the CPU 41 changes the display mode of the map image from the setting state acquired in S1 based on the difference between the current illuminance and the corresponding illuminance. When the current illuminance values detected by the illuminance sensors 19A to 19D are different for each direction, it is desirable to use the highest current illuminance as in S6. However, an average value in four directions may be used.

In S7, the CPU 41 more specifically executes the following process (A) or (B).
(A) When the current illuminance is darker than the corresponding illuminance (Soft processing) Decrease the contrast and brightness. Note that the contrast and brightness can be adjusted by RGB values.
(Hardware processing) The brightness of the backlight 45 is lowered.
(B) When the current illuminance is brighter than the corresponding illuminance (Soft processing) Increase the contrast and brightness. Note that the contrast and brightness can be adjusted by RGB values.
(Hardware processing) The brightness of the backlight 45 is increased.
It should be noted that both (software processing) and (hardware processing) are not necessarily executed, and only one of them may be executed. In addition, it is desirable to increase the display mode change degree as the difference between the current illuminance and the corresponding illuminance is larger.

In S7, when the current illuminance values detected by the illuminance sensors 19A to 19D are different for each direction, the CPU 41 changes the display mode of the map image in consideration of the difference in the current illuminance for each direction. Is desirable. Specifically, the greater the difference between the current illuminance (maximum current illuminance) in the direction in which the highest illuminance is detected among the four directions and the current illuminance (minimum current illuminance) in the direction in which the lowest illuminance is detected. The degree of change of the display mode is increased.
That is, when the difference between the maximum current illuminance and the minimum current illuminance is large, as shown in FIG. 6, stronger light is emitted from the light source (that is, the intensity of the light from the light source is stronger and stronger external light is emitted from the liquid crystal. The possibility of entering the display 15 is high). Therefore, the contrast, brightness, and luminance of the backlight 45 need to be increased greatly.
On the other hand, when the difference between the maximum current illuminance and the minimum current illuminance is small, as shown in FIG. 7, the light source is not irradiated with very strong light (that is, the light intensity of the light source is weak and strong external light is liquid crystal). The possibility of entering the display 15 is low). Therefore, it is not necessary to increase the contrast, brightness, and brightness of the backlight 45 in particular.

  Thereafter, in S8, the CPU 41 determines whether or not the difference between the current illuminance detected in S3 and the corresponding illuminance specified in S5 is less than a predetermined threshold. In addition, when the value of the present illuminance detected by the illuminance sensors 19A to 19D is different for each direction, it is desirable to use the highest current illuminance as the determination target in S8 as in S6. However, an average value in four directions may be used.

  If it is determined that the difference between the current illuminance and the corresponding illuminance is less than a predetermined threshold value (S8: YES), it is determined that it is better to return the display mode of the map image to the original setting state. Migrate to On the other hand, when it is determined that the difference between the current illuminance and the corresponding illuminance is equal to or greater than a predetermined threshold (S8: NO), the state in which the display mode of the map image is changed is maintained.

  In S9, the CPU 41 returns the display mode of the map image to the original setting state. That is, the CPU 41 reads again the display mode of the image currently set in the navigation device 1 from the RAM 42 or the like, and displays the travel guidance screen 50 (see FIG. 3) including the map image based on the read display mode of the image. Displayed on the liquid crystal display 15.

  Next, a shadow drawing processing program executed by the navigation ECU 13 in the navigation device 1 will be described with reference to FIG. FIG. 8 is a flowchart of the shadow drawing processing program according to this embodiment. Here, the shadow drawing processing program is executed when a map image is displayed in the navigation device 1, and a shadow caused by a feature (for example, a building, a tree, a traffic light, etc.) on the map in a necessary situation is displayed on the map image. A program that draws on top.

  First, in the shadow drawing processing program, in S11, the CPU 41 actually sets the periphery of the liquid crystal display 15 (more specifically, the outer wall of the vehicle 60 on which the navigation device 1 is installed) based on the detection results of the illuminance sensors 19A to 19D. The illuminance of the current light being irradiated (current illuminance) is detected. As described above, the illuminance sensors 19A to 19D acquire the illuminance of light irradiated to the vehicle in every four directions, front, rear, left, and right (see FIG. 4).

  Next, in S12, the CPU 41 determines whether or not the current illuminance detected in S3 is greater than or equal to a reference threshold value. Here, the reference threshold value used as the determination reference in S12 is, for example, 10000 lx, and is stored in the RAM 42 or the like. The reference threshold value may be a fixed value or may be appropriately changed according to the surrounding conditions (for example, 30000 lx in summer and 5000 lx in winter). In addition, as described above, the illuminance sensors 19A to 19D acquire the illuminance of the light irradiated to the vehicle for each of the four directions of front, rear, left, and right. If the current illuminance detected in at least one direction is equal to or greater than the reference threshold, It is determined that the illuminance is greater than or equal to the reference threshold (S12: YES).

  If it is determined that the current illuminance is greater than or equal to the reference threshold value (S12: YES), it is determined that a shadow is generated by the feature if the current light irradiation condition, and the process proceeds to S13. On the other hand, when it is determined that the current illuminance is less than the reference threshold (S12: NO), it is recognized that no shadow is generated by the feature under the current light irradiation condition, and the shadow drawing processing program is terminated. To do.

  Thereafter, in S13, the CPU 41 acquires the current date and time. The current date and time may be acquired by the GPS 21, may be acquired by communicating with an external server via the communication module 18, or may be acquired by a timer provided in the navigation device 1. good.

  Next, in S14, based on the current date and time and the illuminance correspondence table 32 (FIG. 2) acquired in S13, the CPU 41 is arranged around the liquid crystal display 15 (more specifically, when the vehicle travels outdoors at the current date and time). Specifically, the corresponding illuminance predicted to be irradiated on the outer wall of the vehicle on which the navigation device 1 is installed is specified.

Subsequently, in S15, the CPU 41 determines whether or not the current illuminance detected in S3 is higher than the corresponding illuminance specified in S5 by an allowable threshold or more. In addition, when the value of the present illuminance detected by the illuminance sensors 19A to 19D is different for each direction, it is desirable to use the highest current illuminance as the determination target in S15. However, an average value in four directions may be used.
In addition, the allowable threshold that is the determination criterion in S15 is, for example, 10000 lx, and is stored in the RAM 42 or the like. The allowable threshold value may be a fixed value or may be appropriately changed according to the surrounding conditions (for example, 30000 lx in summer and 5000 lx in winter). Here, as the situation where the current illuminance is higher than the appropriate illuminance by more than the allowable threshold, for example, in the situation where the surroundings of the vehicle are dark, such as on a rainy day or at night, the surroundings suddenly become brighter due to the approach of the vehicle to the streetlight or the store. There are cases where the light from the headlights of other vehicles is irradiated.

  If it is determined that the current illuminance is higher than the corresponding illuminance by an allowable threshold or more (S15: YES), only bright light is detected temporarily, and it is recognized that the situation does not cause a shadow. Then, the map image display processing program is terminated. On the other hand, if it is determined that the current illuminance is not higher than the permissible threshold value by more than the appropriate illuminance (S15: NO), it is determined that a shadow is generated by the feature if the current light irradiation condition is set, and the process proceeds to S16 And migrate.

In S <b> 16, the CPU 41 specifies the range and density of the shadow caused by the features (for example, buildings, trees, traffic lights, etc.) on the map.
Specifically, the CPU 41 first compares the current illuminance for each direction detected by the illuminance sensors 19A to 19D, and specifies the position of the light source. For example, it is specified that the light source is in the direction in which the illuminance equal to or higher than the reference threshold is acquired (or the direction in which the highest illuminance is obtained when there are a plurality of directions in which the illuminance equal to or higher than the reference value is obtained). And the range of the shadow produced by the light irradiated from a light source is specified based on the positional relationship of the identified light source and the feature on a map. It is also desirable to specify the shadow range in consideration of the shape and height of the feature.
On the other hand, the shadow density is set to a density corresponding to the value of the current illuminance detected by the illuminance sensors 19A to 19D. That is, the CPU 41 sets the shadow density higher as the current illuminance is higher, and sets the shadow density lower as the current illuminance is lower.

  Thereafter, in S17, the CPU 41 is caused by features (for example, buildings, trees, traffic lights, etc.) on the map with respect to the map image displayed on the liquid crystal display 15 based on the range and density set in S16. Draw a shadow. Here, FIG. 9 is a diagram showing an example in which a shadow on a feature is drawn on the travel guide screen 50 shown in FIG.

  In the example shown in FIG. 9, it is the figure which showed an example of the shadow drawn when it determines with having a light source in the east side with respect to a vehicle. As shown in FIG. 9, the driving guidance screen 50 displayed on the liquid crystal display 15 has a shadow 66 in a range predicted to be generated by each building 65 with respect to the west side of each building 65 on the map image 51. Drawn. As a result, the display of the map image can be brought closer to the actual situation around the vehicle, and the uncomfortable feeling caused by the difference between the displayed map image and the actual landscape visually recognized by the user can be reduced.

Thereafter, in S18, the CPU 41 determines whether or not a predetermined time (for example, 30 seconds) has elapsed since the current illuminance detected in S3 becomes less than the reference threshold. In addition, when the value of the present illuminance detected by the illuminance sensors 19A to 19D is different for each direction, it is desirable to use the highest current illuminance as the determination target in S18. However, an average value in four directions may be used.
Here, when a vehicle enters a tunnel or the like or enters behind a building, the current illuminance may temporarily be less than a reference threshold. However, in such a case, the surroundings of the vehicle are only temporarily darkened, and it is recognized that the surrounding situation is a situation in which a shadow is caused by a feature. Therefore, in addition to the current illuminance being less than the reference threshold, the fact that a predetermined time (for example, 30 seconds) has passed since the illuminance is less than the reference threshold is added to the condition of S18.

  If it is determined that the predetermined time has elapsed since the current illuminance is less than the reference threshold value (S18: YES), it is determined that there is no situation where a shadow is caused by the feature, and the process proceeds to S19. On the other hand, if the current illuminance is equal to or higher than the reference threshold value, or if it is determined that the predetermined time has not elapsed since the current illuminance is less than the reference threshold value (S18: NO), a shadow is continuously generated by the feature. It recognizes that it is in the situation, and returns to S16. Then, the shadow is continuously drawn based on the current light irradiation conditions, the shape of the features around the vehicle, and the like. If the direction of the light source and the current illuminance change, the shadow range and density to be drawn change accordingly.

  On the other hand, in S19, the CPU 41 erases the shadow drawn in S17. As a result, the normal travel guidance screen 50 shown in FIG. 3 is displayed.

As described in detail above, in the navigation device 1 according to the present embodiment, the map image display method by the navigation device 1 and the computer program executed by the navigation device 1, the light actually irradiated around the liquid crystal display 15 is reflected. The illuminance (current illuminance) is acquired (S11), and when the current illuminance is greater than or equal to a predetermined reference threshold, a shadow caused by the feature on the map is drawn on the map image (S17). And a large shift between the shadows drawn on the map image can be prevented. For example, it is possible to prevent a shadow from being drawn on the map image even though no shadow is actually generated, or to prevent a shadow from being drawn on the map image even though a shadow is actually generated. As a result, the display of the map image can be brought close to the actual situation around the user, and the uncomfortable feeling caused by the difference between the displayed map image and the actual landscape visually recognized by the user can be reduced.
In addition, since the shadow is drawn at a density according to the current illuminance, it is possible to draw the shadow on the map image at a density close to the actually occurring shadow. As a result, the display of the map image can be brought close to the actual situation around the user, and the uncomfortable feeling caused by the difference between the displayed map image and the actual landscape visually recognized by the user can be reduced.
Further, since the illuminance of the light irradiated to the vehicle 60 moving with the liquid crystal display 15 is acquired as the current illuminance, the shadow of the shadow caused by the feature can be obtained without installing a device for detecting the illuminance of the light on the liquid crystal display 15 itself. It is possible to detect the irradiation state of light around the user that affects the density and range.
Moreover, since the illuminance of the light irradiated to the vehicle 60 is acquired for each of a plurality of directions and a shadow generated by the feature is drawn when the current illuminance in one or more directions is equal to or higher than the reference threshold, the light source is the vehicle 60. Even if it is in a direction other than directly above, it is possible to detect the correct current illuminance. Therefore, it is possible to accurately specify the shadow situation actually caused by the feature.
In addition, since the shadow caused by the feature is drawn in the map image when light is irradiated from the direction in which the illuminance equal to or higher than the reference threshold is acquired, the direction of the light source with respect to the vehicle 60 can be accurately specified, It is possible to accurately specify the range of the shadow actually caused by the feature and reproduce it on the map image.
In addition, when the current illuminance falls below the reference threshold from the reference threshold, the shadow is drawn continuously until the predetermined time has elapsed since the current illuminance is less than the reference threshold. Even if the current illuminance temporarily falls below the reference threshold after entering the shade of the building, it is possible to continuously draw a shadow on the map image. Therefore, it is possible to prevent the shadow from being drawn on the map image even though the shadow is actually generated.
Further, the illuminance of light predicted to be irradiated around the liquid crystal display 15 at the current date and time is acquired as the corresponding illuminance, and when the current illuminance is higher than the corresponding illuminance by an allowable threshold or more, the current illuminance is greater than or equal to the reference threshold Since no shadows are drawn even in the case of rain, the surroundings suddenly become brighter when approaching street lamps or stores in situations where shadows such as rainy days and nights cannot occur, and the light of headlights of other vehicles It is possible to prevent a shadow from being erroneously drawn on a map image when, for example, is irradiated. Therefore, it is possible to prevent the shadow from being drawn on the map image even though no shadow is actually generated.

Note that the present invention is not limited to the above-described embodiment, and various improvements and modifications can be made without departing from the scope of the present invention.
For example, in the present embodiment, the illuminance sensors 19 </ b> A to 19 </ b> D are installed on the outer wall of the vehicle 60, but may be installed in other places as long as it is around the liquid crystal display 15. For example, you may install in the navigation apparatus 1, the console panel in a vehicle, etc. If an illuminance sensor is installed in the navigation device 1, it is possible to detect the illuminance of light applied to the liquid crystal display 15 that displays a map image as the current illuminance, which affects the visibility of the liquid crystal display 15. It becomes possible to detect the irradiation state of light around the user more accurately.

  Further, in the image display processing program (FIG. 5) of the present embodiment, the display mode is changed based on the current illuminance and the corresponding illuminance, particularly in the state where the map image is displayed on the liquid crystal display 15, but other than the map image Even if the image (for example, the menu screen or the facility search screen) is displayed, the display mode may be similarly changed.

  Further, in the shadow drawing processing program (FIG. 8) of the present embodiment, the shadow generated by the building in the map image is particularly drawn. However, other than the building, the features (for example, traffic lights, overheads) to be displayed on the map image are displayed. Also, it is possible to draw a shadow caused by a tree or the like.

  In addition to the navigation device, the present invention can be applied to a device having a function of displaying a map image. For example, the present invention can be applied to a portable terminal such as a mobile phone or a smartphone, a personal computer, a portable music player, or the like (hereinafter referred to as a portable terminal or the like). Further, the present invention can be applied to a system including a server and a mobile terminal. In that case, each step of the above-described map image display processing program (FIG. 2) and shadow drawing processing program (FIG. 5) may be implemented by either a server or a mobile terminal. In addition, when the present invention is applied to a mobile terminal or the like, the travel guidance screen 50 may also show a map image around the current position of a moving body other than a vehicle, for example, a user of a mobile terminal or a two-wheeled vehicle. is there. Furthermore, when the present invention is applied to a portable terminal or the like, it is desirable that the illuminance sensor is installed in the main body of the portable terminal or the like and the illuminance of light irradiated on the display that displays the map image is detected as the current illuminance.

1 Navigation device 13 Navigation ECU
15 Liquid crystal display 19A-19D Illuminance sensor 32 Illuminance correspondence table 41 CPU
42 RAM
43 ROM
45 Backlight 50 Travel guidance screen 51 Map image 60 Vehicle 65 Building 66 Shadow

Claims (11)

Map image display means for displaying a map image including features in the image display device;
Current illuminance acquisition means for acquiring the illuminance of the light applied to the periphery of the image display device as the current illuminance;
A map image display system comprising: a shadow drawing unit that draws a shadow generated by the feature in the map image when the current illuminance is equal to or higher than a reference threshold value.   2. The map image display system according to claim 1, wherein the current illuminance acquisition unit acquires, as the current illuminance, illuminance of light irradiated to a moving body that moves together with the image display device. The current illuminance acquisition means acquires the illuminance of light irradiated to the moving body for each of a plurality of directions,
3. The map image according to claim 2, wherein the shadow drawing unit draws the shadow when the current illuminance in one or more of the plurality of directions is not less than the reference threshold value. 4. Display system.   The shadow drawing means draws, in the map image, a shadow generated by the feature when light is irradiated from a direction in which illuminance equal to or higher than the reference threshold is acquired among the plurality of directions. The map image display system according to claim 3.   The map image display system according to claim 1, wherein the shadow drawing unit draws the shadow at a density corresponding to the current illuminance.   The shadow drawing means continues the shadow until a predetermined time elapses after the current illuminance falls below the reference threshold when the current illuminance falls below the reference threshold from the reference threshold. The map image display system according to any one of claims 1 to 5, wherein the map image display system is drawn. A date and time acquisition means for acquiring the current date and time;
Corresponding illuminance acquisition means for acquiring the illuminance of light predicted to be irradiated around the image display device at the current date and time as corresponding illuminance,
The shadow drawing unit does not draw the shadow when the current illuminance is higher than the corresponding illuminance by an allowable threshold or more, even when the current illuminance is higher than the reference threshold. The map image display system according to any one of claims 1 to 6.   The map image display system according to claim 1, wherein the current illuminance acquisition unit acquires the illuminance of light applied to the image display device as the current illuminance. A map image display device for displaying a map image including a feature,
Current illuminance acquisition means for acquiring the illuminance of light irradiated around the map image display device as the current illuminance;
A map image display device comprising: a shadow drawing unit that draws a shadow generated by the feature in the map image when the current illuminance is equal to or higher than a reference threshold value. A map image display step for displaying a map image including a feature in the image display device;
Current illuminance acquisition step for acquiring the illuminance of light irradiated around the image display device as the current illuminance;
A map image display method comprising: a shadow drawing step of drawing a shadow caused by the feature in the map image when the current illuminance is equal to or higher than a reference threshold value. On the computer,
A map image display function for displaying a map image including features in the image display device;
A current illuminance acquisition function for acquiring the illuminance of light applied to the periphery of the image display device as the current illuminance;
A shadow rendering function for rendering a shadow caused by the feature in the map image when the current illuminance is greater than or equal to a reference threshold;
A computer program for executing

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