Background image display method for display, background image display device, and background image display program

Abstract

In this background image display method for a display, a local sunrise time and a local sunset time are determined on the basis of location information and date information, a sunrise time slot for displaying a first image set (S1) is set on the basis of the local sunrise time, a sunset time slot for displaying a second image set (S2) is set on the basis of the local sunset time, and a daytime time slot with a variable time length for displaying a third image set (S3) is set between the sunrise time slot and the sunset time slot. Furthermore, in this method, all the images of the first image set (S1) are sequentially displayed in the sunrise time slot, all the images of the second image set (S2) are sequentially displayed in the sunset time slot, and at least some of the images in the third image set (S3) are displayed in the daytime time slot.

Description

Background image display method for display, background image display device, and background image display program

[0001] The present invention relates to a background image display method, a background image display device, and a background image display program for displaying a time-series changing scene of a day as a background image corresponding to the actual time on the display of a control device.

[0002] Patent Literature 1 discloses a background image display device for a display that displays the sun's position, which changes over time throughout the day, as a background image corresponding to the actual time on the display of a mobile terminal. In this background image display device, an image showing the sun's position, which changes from moment to moment, is displayed on the display as if it were moving along a sine wave. In other words, images showing the sun's position for all times of day are prepared, and the corresponding image is displayed on the display at each time. Furthermore, by changing the display of the sun, this background image display device is able to distinguish between the sun during the time period from sunrise to sunset and the sun outside of this time period.

[0003] If images of the sun are prepared for all times of the day in this way, the amount of data stored in the background image display device becomes large.

[0004] The present invention has been made with an eye on such problems, and one of its objects is to provide a background image display method, a background image display device, and a background image display program that can reduce the amount of data.

[0005] Japanese Patent Application Laid-Open No. 2019-164825

[0006] The present invention relates to a background image display method for a display, which includes preparing a first image set consisting of a plurality of images arranged in a time series of a sunrise time period including sunrise time, a second image set consisting of a plurality of images arranged in a time series of a sunset time period including sunset time, and a third image set consisting of a plurality of images arranged in a time series of a daytime time period between the sunrise time period and the sunset time period. The method then determines the local sunrise time and the local sunset time based on location information and date information, sets a sunrise time period during which the first image set is displayed based on the local sunrise time, sets a sunset time period during which the second image set is displayed based on the local sunset time, and sets a daytime time period between the first and the sunset time periods with a variable duration during which the third image set is displayed. Furthermore, the method sequentially displays all images of the first image set during the sunrise time period, all images of the second image set during the sunset time period, and displays at least some images of the third image set during the daytime time period.

[0007] Since the intensity of sunlight is less likely to change during daytime hours, at least a portion of the third image set is displayed on the display without chopping up the images of the third image set into small pieces during such daytime hours, thereby reducing the amount of data used by the control device.

[0008] FIG. 1 is a block diagram showing a background image display device for a display of a first embodiment; FIG. 2 is a schematic diagram showing a background image of a first embodiment; FIG. 3 is a table showing an example of a difference in sunrise time depending on the season, and FIG. 4 is a table showing an example of a difference in sunset time depending on the season; FIG. 5 is a table showing an example of a difference in sunrise time and sunset time depending on the region; FIG. 6 is an explanatory diagram showing a calculation logic for sunrise time and sunset time; FIG. 7 is a table showing a method for adjusting the display time of a background image during daytime and nighttime hours in a first embodiment; FIG. 8 is a table showing a method for adjusting the display time of a background image during daytime and nighttime hours in a second embodiment; FIG. 9 is a table showing a method for adjusting the display time of a background image during daytime and nighttime hours in a third embodiment; FIG. 10 is an explanatory diagram showing an example of determination of midnight sun and polar night; FIG. 11 is a table showing a method for adjusting the display time of a background image in a fourth embodiment;

[0009] Hereinafter, an embodiment of the background image display device of the present invention will be described with reference to the drawings. In the following embodiment, an example will be described in which the background image display device of the present invention is applied to the displays of an in-vehicle infotainment (IVI) 20 and a meter 30, which are control devices mounted on a vehicle.

[0010] The background image display device is a device that displays a day's scenery that changes over time as a background image corresponding to the actual time on the first display unit 26 and second display unit 34, which are the displays of the IVI 20 and meter 30 installed in the vehicle.

[0011] 1, the IVI 20 includes a date and location information determination unit 21, an operation reception unit 22, a first setting unit 23, a first image storage unit 24, a first image switching unit 25, and a first display unit 26, which constitute a background image display device. Various processes (background image display methods) associated with the date and location information determination unit 21 and the like are performed using a background image display program executed by a computer connected to the first display unit 26 and the second display unit 34, which are displays.

[0012] The date and location information determination unit 21 determines the location information (latitude and longitude) of the vehicle using a global positioning system (GPS) installed in the vehicle, and determines date information including the time in the local area where the vehicle is located by acquiring Coordinated Universal Time (UTC) and setting the time zone. The local area where the vehicle is located and the time in this local area may also be set by the user P of the vehicle.

[0013] A theme to be displayed on the first display unit 26 and the second display unit 34 as the background image I is input to the operation reception unit 22 by the vehicle user P. As shown in FIG. 2 , in this embodiment, the theme of the background image I is a desert Ia (shown in gray and black in FIG. 2 ), with a sky Ib above the desert Ia. Note that the theme of the background image I is not limited to the desert Ia, and may be something else that can be contrasted with the sky Ib, such as a mountain range, a building, or a plant.

[0014] The first image storage unit 24 prepares and stores a plurality of images corresponding to the time-series changes in the position and brightness of the sun throughout the day. In this embodiment, the first image storage unit 24 stores 16 types of images in which the color (including the color of shadows) of the desert Ia and the brightness of the sky Ib shown in FIG. 2 change according to the position and brightness of the sun. The first image storage unit 24 also stores a first image set S1 consisting of a plurality of images in a time series of a sunrise time period including sunrise time; a second image set S2 consisting of a plurality of images in a time series of a sunset time period including sunset time; a third image set S3 consisting of a plurality of images in a time series of a daytime time period between sunrise and sunset; and a fourth image set S4 consisting of a plurality of images in a time series of a nighttime time period between sunset and sunrise. The first to fourth image sets S1 to S4 each contain 15 to 50 images in total. The first to fourth image sets S1 to S4 will be described in detail later.

[0015] The first setting unit 23 dynamically creates a table by calculating the local sunrise time and local sunset time at the location where the vehicle is located based on the date information and location information acquired by the date and location information determination unit 21. The reason why date information is considered as one of the parameters when calculating the local sunrise time and local sunset time is because sunrise times and sunset times can vary significantly depending on the season. As shown in FIG. 3A , for example, in London, England, the sunrise time on July 1 is 3:46:58 (3:46 minutes, 58 seconds) and the sunrise time on January 1 is 8:06:02, meaning there is a difference of more than four hours between the two sunrise times. Also, as shown in FIG. 3B , for example, in Melbourne, Australia, the sunset time on May 1 is 16:33:41 and the sunset time on January 1 is 20:45:27, meaning there is a difference of more than four hours between the two sunset times. The reason why location information is considered as one of the parameters when calculating the local sunrise time and local sunset time is that sunrise and sunset times can vary significantly depending on the region. As shown in Figure 4, the sunrise time in Tehran, Iran is 10:42:14, which is significantly different from the times in Paris, France, Tokyo, Japan, Moscow, Russia, and New York, USA. Furthermore, the sunset time in Paris, France is 20:04:07, the sunset time in Tehran, Iran is 0:20:36, and the sunset time in Moscow, Russia is 21:05:05. These sunset times are significantly different from the times in Tokyo, Japan, and New York, USA.

[0016] As shown in FIG. 5 , when calculating the local sunrise time and local sunset time, the function “f(locale, date)” is executed based on the locality (locale) based on the vehicle's position information and the date (date) based on the date information. The function “f(locale, date)” obtains the local sunrise time in Coordinated Universal Time (UTC) in the item indicated by “(rising_time)(UTC)” (the top line of the program), and the local sunset time in Coordinated Universal Time (UTC) in the item indicated by “(setting_time)(UTC).” The time zone is then set in the item indicated by “(time_zone).” For example, if the locality is Tokyo, a time zone including Tokyo is set. When setting this time zone, daylight saving time (DST) is taken into account in the item “(Is_summerTime).” Here, daylight saving time (DST) is a time established in certain regions, such as the United States, Europe, Canada, Australia, New Zealand, Mexico, and Brazil, by moving clock hands forward by one hour during periods when sunrise occurs earlier, in order to make effective use of the time periods when sunlight is up. Then, the local sunrise time corresponding to the local time is obtained in the item indicated by "(rising_time) (locale)," and the local sunset time corresponding to the local time is obtained in the item indicated by "(setting_time) (locale)." For example, if the local location is Tokyo, the local sunrise time and local sunset time obtained by adding 9 hours to Coordinated Universal Time are obtained. The first setting unit 23 sets a sunrise time zone including the local sunrise time and a sunset time zone including the local sunset time based on the local sunrise time and local sunset time.

[0017] Next, a method for setting the sunrise time zone, sunset time zone, daytime time zone, and nighttime time zone by the first setting unit 23, and a method for adjusting the intervals between images in the daytime time zone and nighttime time zone will be described with reference to Fig. 6. In the example of Fig. 6, an example will be described in which the vehicle is located in France.

[0018] First, as shown on the left side of FIG. 6, a reference table T1 is set as a reference for adjusting the display time of the background image during daytime and nighttime hours in accordance with changes in the sunrise and sunset times in France.

[0019] Next, the sunrise time zone for displaying the first image set S1 is set based on 5:16, a typical local sunrise time in France. This sunrise time zone is shifted while remaining a fixed length as the local sunrise time changes depending on the time of year. In the reference table T1 of this embodiment, the time zone from 4:00 to 6:59 is defined as the sunrise time zone, and this sunrise time zone has four time zones: 4:00 to 4:59, 5:00 to 5:59, 6:00 to 6:29, and 6:30 to 6:59. As shown in the background image index, the fourth to seventh background images (numbered "4" to "7") out of the 16 background images are assigned to these four time zones as the first image set S1 (indicated by dots in the background index in FIG. 6 ). The background image "4" is located adjacent to the nighttime background image "3," which will be described later, and has darker desert Ia and sky Ib than the background image "5." The background images for "4" to "7" are set so that the background image for "4" is the darkest and becomes brighter as it approaches the background image for "7." During the sunrise period, the background images for "4" to "7" are each used once in succession, thereby dividing the background images into smaller sections. During the sunrise period, the brightness of the sun changes rapidly compared to the daytime period described below. Therefore, during this period, the background images are faithfully reproduced on the first display unit 26 and the second display unit 34 inside the vehicle, thereby synchronizing the atmosphere inside the vehicle with the real world outside the vehicle.

[0020] Next, the sunset time zone for displaying the second image set S2 is set based on 16:30, a typical local sunset time in France. This sunset time zone is shifted while remaining a fixed length when the local sunset time changes depending on the time of year. In the reference table T1 of this embodiment, the time zone from 15:00 to 18:59 is defined as the sunset time zone, and this sunset time zone has four time zones: 15:00 to 15:59, 16:00 to 16:59, 17:00 to 17:59, and 18:00 to 18:59. As shown in the background image index, the twelfth to fifteenth background images (indicated by the numbers "12" to "15") of the 16 background images in the second image set S2 (shown by hatching in the background index in FIG. 6) are assigned to these four time zones, respectively. The background image for "12" is located adjacent to the background image for "11" during the daytime period (described later), and the desert Ia and sky Ib are brighter than the background image for "13." The background images for "12" through "15" are set so that "12" is the brightest and gradually darker toward "15." During sunset, the background images for "12" through "15" are each used once in succession, resulting in a finely divided background image. Because the brightness of the sun changes dramatically during sunset compared to daytime periods (described later), faithful reproduction of the background images on the first display unit 26 and the second display unit 34 within the vehicle during this time period synchronizes the atmosphere inside the vehicle with the real world outside the vehicle.

[0021] Next, a daytime period is set between the sunrise and sunset periods, during which the third image set S3 (shown as a solid background in the background index in FIG. 6 ) is displayed. In the reference table T1 of this embodiment, the period from 7:00 to 14:59 is defined as the daytime period, and this daytime period is divided into eight time periods, each divided into one-hour segments. The eighth to eleventh background images (numbered "8" to "11") of the 16 background images are assigned to these eight time periods as the third image set S3. More specifically, the eight time periods are assigned background images "8," "8," "9," "9," "10," "10," "11," and "11." The background images "8" to "11" correspond to images taken during daytime periods when the sun is relatively high in the sky and the lighting conditions are less variable than those during sunrise and sunset periods. Furthermore, the lighting conditions change less for the background images at "9" and "10," which are located in the center of the time series, than for the background images at "8" and "11," which are located at both ends of the time series. Because the scenery is less likely to change during the daytime, we sacrifice synchronization between the real world outside the vehicle and the atmosphere inside the vehicle by using each background image multiple times, thereby reducing the number of background image types and reducing the amount of data.

[0022] The display time of each image in the third image set S3 is adjusted to correspond to the change in daytime hours based on the time of year in the local area, in this case France. During this adjustment, the background image in the middle of the time series in the third image set S3 is adjusted preferentially. Furthermore, the number of background images displayed in the third image set S3 is increased or decreased to correspond to the change in daytime hours.

[0023] After the daytime period is set, a nighttime period is set between the sunset period and the sunrise period, during which the fourth image set S4 (shown by cross-hatching in the background index in FIG. 6 ) is displayed. In the reference table T1 of this embodiment, the period from 19:00 to 3:59 is defined as the nighttime period, and this nighttime period has 11 time periods divided into one-hour or 30-minute intervals. The first, second, third, and sixteenth background images (represented by the numbers "1," "2," "3," and "16") are assigned to these 11 time periods as the fourth image set S4. More specifically, one "1" background image, four "2" background images, four "3" background images, and two "16" background images are assigned to the 11 time periods. Because the sun is not shining during the nighttime period, the amount of light is less likely to change compared to the sunrise and sunset periods. Therefore, at the expense of synchronizing the real world outside the vehicle with the atmosphere inside the vehicle, the background image "1" is used once, but each of the other background images is used multiple times, thereby reducing the number of background images and reducing the amount of data.

[0024] The display time of each image in the fourth image set S4 is adjusted to correspond to the expansion or contraction of daytime hours based on the change in the season of the local area, in this case France. The number of images displayed in the fourth image set S4 is increased or decreased to correspond to the expansion or contraction of nighttime hours.

[0025] 6, the local sunrise time in France in July is 5:50 and the local sunset time is 21:57. Therefore, in table T2, the local sunrise time is within the same time period of 5:00 to 5:59 as in reference table T1, but the local sunset time has shifted to the time period of 21:00 to 21:59, which is different from reference table T1. Therefore, in table T2, the sunset time period has been changed from the time period of 15:00 to 18:59 in reference table T1 to the time period of 20:30 to 23:59.

[0026] In addition, due to this change in the sunset time period, the daytime time period has been extended, while the nighttime time period has been shortened.

[0027] In table T2, the daytime period has been extended from 7:00 to 14:59 in reference table T1 to 7:00 to 20:29. In conjunction with this extension of the daytime period, images in the middle of the time series in the third image set S3 have been preferentially added. This means that, compared to reference table T1, two background images for "9" have been added, and two background images for "10" have been added. Furthermore, one background image each for "8" and "11" has been added.

[0028] On the other hand, the nighttime period has been reduced from 19:00 to 3:59 in the reference table T1 to 0:00 to 3:59. Along with this reduction in the nighttime period, the number of background images for "2" has been reduced by two, the number of background images for "3" by three, and the number of background images for "16" by one.

[0029] 6, the local sunrise time in France in December is 8:21 and the local sunset time is 16:57. Therefore, in Table T3, the local sunset time falls within the same time period of 16:00 to 16:59 as in Reference Table T1, but the local sunrise time has shifted to the time period of 8:00 to 8:59, unlike Reference Table T1. Therefore, in accordance with this shift in local sunrise time, the sunrise time period in Table T3 has changed from the time period of 4:00 to 6:59 in Reference Table T1 to the time period of 7:00 to 10:59.

[0030] In addition, due to this change in the sunrise time, the daytime hours have been shortened, while the nighttime hours have been extended.

[0031] In table T3, the daytime time period has been reduced from 7:00 to 14:59 in reference table T1 to 11:00 to 14:59. Along with this reduction in the daytime time period, the background images for "8," "9," "10," and "11" have been reduced by one each.

[0032] On the other hand, the nighttime period has been extended from 19:00 to 3:59 in the reference table T1 to 19:00 to 6:59. With this extension of the nighttime period, one background image for "1" has been added, two background images for "3" have been added, and one background image for "16" has been added.

[0033] The first image switching unit 25 switches the images stored in the first image storage unit 24 based on the correspondence between the time period set by the first setting unit 23 and the background image index.

[0034] The first display unit 26 is a display provided in the IVI 20 and displays the image switched by the first image switching unit 25 .

[0035] 1, the meter 30 includes a second setting unit 31, a second image storage unit 32, a second image switching unit 33, and a second display unit 34, which constitute a background image display device. Various processes associated with the second setting unit 31 and the like are performed using a background image display program executed by a computer connected to the first display unit 26 and the second display unit 34, which are displays.

[0036] The second setting unit 31 is capable of communicating with the first setting unit 23 and has a configuration similar to that of the first setting unit 23. Like the first setting unit 23, the second setting unit 31 sets the above-mentioned reference table T1 and makes adjustments in accordance with changes in the sunrise time zone and sunset time zone in tables T2 and T3 based on the vehicle's position information and date information.

[0037] The second image storage section 32 has the same configuration as the first image storage section 24, and stores 16 types of background images, background images "1" to "16".

[0038] The second image switching unit 33 has a configuration similar to that of the first image switching unit 25, and switches the images stored in the second image storage unit 32 based on the correspondence between the time period set by the second setting unit 31 and the background image index.

[0039] The second display unit 34 is a display provided on the meter 30, and has the same configuration as the first display unit 26. The second display unit 34 displays the image switched by the second image switching unit 33.

[0040] As described above, in the first embodiment, the first image storage unit 24 and the second image storage unit 32 each have a first image set S1 corresponding to a sunrise time zone, a second image set S2 corresponding to a sunset time zone, and a third image set S3 corresponding to a daytime time zone. The first setting unit 23 and the second setting unit 31 set a sunrise time zone for displaying the first image set S1 based on the local sunrise time, a sunset time zone for displaying the second image set S2 based on the local sunset time, and a daytime time zone between the two with a variable duration for displaying the third image set S3. The first display unit 26 and the second display unit 34 sequentially display all images in the first image set S1 during the sunrise time zone, sequentially display all images in the second image set S2 during the sunset time zone, and display at least some background images in the third image set S3 during the daytime time zone. When the sun is rising or setting during daytime, the light intensity is less likely to change compared to when the sun is rising or setting during sunrise or sunset. Therefore, by displaying at least some of the background images rather than all of the types of background images in the third image set S3 during the daytime as in this embodiment, it is possible to reduce the amount of data used by the IVI 20 and the meter 30. Furthermore, because the intensity of sunlight changes rapidly during sunrise and sunset, all of the types of background images in the first image set S1 and the second image set S2 are displayed on the first display unit 26 and the second display unit 34. Therefore, during sunrise and sunset, the background images are displayed in small increments, allowing the scenery outside the vehicle to be synchronized with the atmosphere inside the vehicle.

[0041] In this embodiment, the first setting unit 23 and the second setting unit 31 set a nighttime period between the sunset time period and the sunrise time period, during which the fourth image set S4 is displayed for a variable length of time. The first display unit 26 and the second display unit 34 display at least some of the background images in the fourth image set S4 during the nighttime period. Since the sun is not out during the nighttime period, it is clear that the amount of light is unlikely to change. Therefore, by displaying at least some of the background images in the fourth image set S4 during the daytime period, rather than all of the background images in the fourth image set S4 as in this embodiment, the amount of data used by the IVI 20 and the meter 30 can be reduced.

[0042] Furthermore, in this embodiment, when expanding or contracting the third image set S3, the background image that is central in time series within the third image set S3 is preferentially expanded or contracted. In the third image set S3 corresponding to the daytime period, the background image that is central in time series is a background image taken during daytime or close to daytime, which in this embodiment is the background images "9" and "10." These background images for "9" and "10" are images in which the position of the sun changes less than the background images for "8" and "11." Therefore, by preferentially expanding or contracting the background images for "9" and "10," in which the position of the sun changes less, it is possible to prevent a sudden loss of synchronization between the scenery outside the vehicle and the atmosphere inside the vehicle.

[0043] In this embodiment, the number of images displayed in the third image set S3 is increased or decreased in response to changes in the daytime hours, so that the amount of data in the third image set S3 can be adjusted when changes in the daytime hours occur.

[0044] FIG. 7 shows a method for adjusting the display time of the background image during the daytime and nighttime periods in accordance with changes in the sunrise and sunset periods in the second embodiment.

[0045] 7, the local sunrise time is set to the time period from 5:00 to 5:59, and the sunrise time period is set to the time period from 4:00 to 6:59. In the time period from 6:00 to 6:59, the background image of "6" is assigned to the time period from 6:00 to 6:29, while the background image of "7" is assigned to the time period from 6:30 to 6:59.

[0046] In addition, in table T11, the local sunset time is in the time zone of 16:00 to 16:59, and the sunset time zone is set to 15:00 to 18:59.

[0047] Between the sunrise time period and the sunset time period, a daytime time period is set, which runs from 7:00 to 14:59. Two background images each of "8," "9," "10," and "11" are assigned to the daytime time period.

[0048] Furthermore, a nighttime period is set between the sunset time period and the sunrise time period. This nighttime period is from 19:00 to 3:59. In the 20:00 to 20:59 time period, the background image "16" is assigned to the time period from 20:00 to 20:29, while the background image "2" is assigned to the time period from 20:30 to 20:59. In the 2:00 to 2:59 time period, the background image "2" is assigned to the time period from 2:00 to 2:29, while the background image "3" is assigned to the time period from 2:30 to 2:59. In this manner, the time periods in which two background images are assigned for 30 minutes each within one hour, in this embodiment, the time periods from 20:00 to 20:59 and 2:00 to 2:59, are the periods in which background images are deleted or changed when the daytime hours are extended due to changes in the sunrise and sunset time periods.

[0049] In addition, in table T12, which is the second from the left in Figure 7, the local sunrise time is in the 4:00 to 4:59 time zone, and the sunrise time zone has been changed from 4:00 to 6:59 in table T11 to 3:00 to 5:59.

[0050] In addition, in table T12, the local sunset time is in the time period of 17:00 to 17:59, and the sunset time period has been changed from the time period of 15:00 to 18:59 in table T11 to the time period of 16:00 to 19:59.

[0051] In addition, due to changes in the sunrise and sunset times, the daytime hours have been extended and the nighttime hours have been shortened.

[0052] In table T12, the daytime time period is extended from 7:00 to 14:59 in table T11 to 6:00 to 15:59. During this extension, the background images "9" and "10" in the chronological center of the third image set S3 are increased by one each.

[0053] Furthermore, the nighttime period is reduced from 19:00 to 3:59 in table T11 to 20:00 to 2:59. During this reduction, the background image "2" for the 2:00 to 2:59 period in table T11 is deleted, and the entire period is replaced with the background image "3." The background images "16" and "2" for the 20:30 to 20:59 period and the background image "3" for 23:00 to 23:59 are also deleted.

[0054] If there is a request to reduce the amount of data for the sunrise time period in table T12, the sunrise time period may be shortened. This shortening of the sunrise time period is performed, for example, by replacing the background images "6" and "7" for the time period from 5:00 to 5:59 with the background image "8" from the third image set S3 for the daytime time period. This kind of shortening of the sunrise time period may also be performed using tables T13 and T14, which will be described later.

[0055] Next, in table T13, which is the third from the left in Figure 7, the local sunrise time is in the 3:00 to 3:59 time zone, and the sunrise time zone has been changed from 3:00 to 5:59 in table T12 to 2:00 to 4:59.

[0056] In addition, in table T13, the local sunset time is in the time period of 18:00 to 18:59, and the sunset time period has been changed from 16:00 to 19:59 in table T12 to 17:00 to 20:59.

[0057] In addition, due to changes in the sunrise and sunset times, the daytime hours have been extended and the nighttime hours have been shortened.

[0058] In table T13, the daytime time period has been extended from 6:00 to 15:59 in table T12 to 5:00 to 16:59. When this daytime time period is extended, the background images "8" and "11" at both ends of the time series in the third image set S3 are increased by one each. As a result, in table T13, three background images each of "8," "9," "10," and "11" are arranged in the daytime time period.

[0059] Furthermore, the nighttime period is reduced from 20:00 to 2:59 in table T12 to 21:00 to 1:59 in table T12. When reducing the nighttime period, the background image of "3" in the time period from 1:00 to 1:59 in table T12 and the background image of "3" in the time period from 2:00 to 2:59 in table T12 are deleted.

[0060] Next, in table T14, which is located on the far right side of Figure 7, the local sunrise time is in the 2:00 to 2:59 time zone, and the sunrise time zone has been changed from 2:00 to 4:59 in table T13 to 1:00 to 3:59.

[0061] In addition, in table T14, the local sunset time is in the time period of 19:00 to 19:59, and the sunset time period has been changed from the time period of 17:00 to 20:59 in table T13 to the time period of 18:00 to 21:59.

[0062] In addition, due to changes in the sunrise and sunset times, the daytime hours have been extended and the nighttime hours have been shortened.

[0063] In table T14, the daytime time period is extended from 5:00 to 16:59 in table T13 to 4:00 to 17:59. When this daytime time period is extended, the background images "9" and "10" that are located in the middle of the time series in the third image set S3 in table T13 are increased by one each.

[0064] Furthermore, the nighttime period has been reduced from 21:00 to 1:59 in table T13 to 22:00 to 0:59. When reducing the nighttime period, the background image "2" for the time period 22:00 to 22:59 in table T13 and the background image "2" for the time period 1:00 to 1:59 in table T13 have been deleted, and the positions of the background image "1" for the time period 0:00 to 0:59 in table T13 and the background image "3" for the time period 23:00 to 23:59 in table T13 have been swapped.

[0065] In this embodiment, an example has been described in which the number of background images in the daytime period is increased by two, which is an even number, but if there is a fraction, that is, if an odd number is added, the number of background images closer to the center of the time series of daytime periods (midday) should be increased. This is because the change in the solar elevation angle per unit time is smaller at midday than at times closer to sunrise or sunset, and the change in the intensity of light is also smaller.

[0066] In the second embodiment, as in the first embodiment, first to third image sets S3 are stored and sunrise, sunset, and daytime periods are set. The first display unit 26 and the second display unit 34 sequentially display all background images in the first image set S1 during sunrise, sequentially display all background images in the second image set S2 during sunset, and display at least some background images in the third image set S3 during daytime. Therefore, by displaying at least some of the background images rather than all of the background images in the third image set S3 during daytime, the amount of data used by the IVI 20 and the meter 30 can be reduced. Furthermore, by dividing the background images into smaller parts during sunrise and sunset, the scenery outside the vehicle can be synchronized with the atmosphere inside the vehicle.

[0067] FIG. 8 shows a method for adjusting the display time of the background image during the daytime and nighttime periods in accordance with changes in the sunrise and sunset periods in the third embodiment.

[0068] On the leftmost side of FIG. 8, a table similar to table T11 in the embodiment of FIG. 7 is arranged.

[0069] In addition, in table T22, which is the second from the left in Figure 8, the local sunrise time is in the 6:00 to 6:59 time zone, and the sunrise time zone has been changed from 4:00 to 6:59 in table T11 to 5:00 to 7:59.

[0070] In table T22, the local sunset time is in the time zone of 15:00 to 15:59, and the sunset time zone has been changed from the time zone of 15:00 to 18:59 in table T11 to the time zone of 14:00 to 17:59.

[0071] In addition, due to changes in the sunrise and sunset times, the daytime hours have been shortened and the nighttime hours have been extended.

[0072] In table T22, the daytime time period has been reduced from 7:00 to 14:59 in table T11 to 8:00 to 13:59. During this reduction, the background images "8" and "11" at both ends of the time series in the third image set S3 have been deleted one by one.

[0073] Additionally, the nighttime period is extended from 19:00 to 3:59 in table T11 to 18:00 to 4:59. During this extension, the background images "16" and "2" for the 20:00 to 20:59 period, which were assigned to a 30-minute time period, and the background images "2" and "3" for the 2:00 to 2:59 period, are changed to be assigned to a 1-hour time period.

[0074] Next, in table T23, which is the third from the left in Figure 8, the local sunrise time is in the 7:00 to 7:59 time zone, and the sunrise time zone has been changed from 5:00 to 7:59 in table T22 to 6:00 to 8:59.

[0075] In addition, in table T23, the local sunset time is in the time period from 14:00 to 14:59, and the sunset time period has been changed from the time period from 14:00 to 17:59 in table T22 to the time period from 13:00 to 16:59.

[0076] In addition, due to changes in the sunrise and sunset times, the daytime hours have been shortened and the nighttime hours have been extended.

[0077] In table T23, the daytime time period has been reduced from 8:00 to 13:59 in table T22 to 9:00 to 12:59. During this reduction, the background images "9" and "10" in the middle of the time series in the third image set S3 in table T22 have been deleted one by one.

[0078] Furthermore, the nighttime period is extended from 18:00 to 4:59 in table T22 to 17:00 to 5:59. During this extension, the background image for "1" is increased by one, and the background image for "3" is increased by one.

[0079] Next, in table T24, which is located on the far right side of Figure 8, the local sunrise time is in the 8:00 to 8:59 time zone, and the sunrise time zone has been changed from 6:00 to 8:59 in table T23 to 7:00 to 9:59.

[0080] In addition, in table T24, the local sunset time is in the time zone of 13:00 to 13:59, and the sunset time zone has been changed from the time zone of 13:00 to 16:59 in table T23 to the time zone of 12:00 to 15:59.

[0081] Due to changes in the sunrise and sunset times, the daytime hours have been shortened and the nighttime hours have been extended.

[0082] In table T24, the daytime period is reduced from 9:00 to 12:59 in table T23 to 10:00 to 11:59. When reducing the daytime period, the background images "8" and "11" located at both ends of the time series in the third image set S3 in table T23 are deleted one by one, and the background image "10" is replaced with the background image "9." As a result, two background images "9" are displayed during the daytime period from 10:00 to 11:59. When the number of background images displayed during the daytime period is reduced to less than four, one background image from the third image set S3 is assigned. The reason for using one background image is to prevent the vehicle user P from perceiving the sun's position as changing drastically in a short period of time if two or more background images are displayed on the first display unit 26 and the second display unit 34 during the relatively short daytime period, even though the sun's position generally changes less rapidly during daytime than during sunrise and sunset.

[0083] In the third embodiment, as in the first embodiment, first to third image sets S3 are stored and sunrise, sunset, and daytime periods are set. The first display unit 26 and the second display unit 34 sequentially display all background images in the first image set S1 during sunrise, all background images in the second image set S2 during sunset, and at least some background images in the third image set S3 during daytime. Therefore, by displaying at least some of the background images rather than all of the background images in the third image set S3 during daytime, the amount of data used by the IVI 20 and the meter 30 can be reduced. Furthermore, by dividing the background images into smaller parts during sunrise and sunset, the scenery outside the vehicle can be synchronized with the atmosphere inside the vehicle.

[0084] Next, an example of determining the midnight sun and polar night related to the fourth and fifth embodiments will be described.

[0085] Midnight sun is generally a phenomenon in which the sun does not set at night. Polar night is generally a phenomenon in which the sun does not rise at all during the day. Midnight sun and polar night occur in areas north of 66 degrees north latitude or south of 66 degrees south latitude. Here, areas north of 66 degrees north latitude include, for example, Norway, Sweden, Russia, the United States (some areas), Canada, Iceland, and Greenland. Areas south of 66 degrees south latitude include, for example, Antarctica. In the Northern Hemisphere, midnight sun occurs near the summer solstice, and polar night occurs near the winter solstice. Meanwhile, in the Southern Hemisphere, polar night occurs near the summer solstice, and midnight sun occurs near the winter solstice.

[0086] Next, a method for determining the midnight sun and polar night will be described with reference to Fig. 9. Fig. 9 shows an example of Tromso, Norway, which is at a latitude (north) of 69.68 degrees.

[0087] The midnight sun is determined based on the location information and date information acquired by the date and location information determination unit 21. With regard to the location information, the condition for the midnight sun is that the vehicle is located in an area north of 66 degrees north latitude or south of 66 degrees south latitude. With regard to the date information, the condition for the midnight sun is that the sunset time is after 23:59, the difference between the sunrise time and the sunset time is a predetermined time, within one hour in this example, and the daytime hours are longer than the nighttime hours.

[0088] In Tromsø, Norway, located in the Northern Hemisphere, midnight sun can occur from April 1st to August 31st. As shown in FIG. 9 , on May 17th, sunrise is 1:02 and sunset is 00:18, a difference of 44 minutes. On July 1st, sunrise and sunset are both 1:00, with no difference between them. Table T31, which indicates the background (indicating day or night) for each time period, is similar for both May 17th and July 1st. In Table T31, the daytime period is from 3:00 to 23:59, while the nighttime period is from 0:00 to 2:59. Therefore, since the daytime period is longer than the nighttime period, both May 17th and July 1st are determined to be experiencing midnight sun. For the sake of simplicity, in Table T31, the time period from 0:00 to 2:59 has been described as the nighttime period, but in the example of Figure 9, the time period from 0:00 to 2:59 may actually include the sunrise time period and the sunset time period.

[0089] Furthermore, polar night is determined based on the location information and date information acquired by the date and location information determination unit 21. With regard to the location information, the condition for polar night is that the vehicle is located in an area north of 66 degrees north latitude or south of 66 degrees south latitude. With regard to the date information, the condition for polar night is that the sunset time is after 23:59, the difference between the sunrise time and the sunset time is a predetermined time, within one hour in this example, and the nighttime hours are longer than the daytime hours.

[0090] In Tromsø, Norway, located in the Northern Hemisphere, polar night can occur from November 1 to February 28. As shown in FIG. 9 , on November 28, sunrise and sunset are both 1:00 AM, with no difference between them. Furthermore, in table T32, which shows the background for time periods on November 28, the nighttime period is 1:00 PM to 9:59 AM, while the daytime period is 10:00 AM to 12:59 PM. Therefore, since the nighttime period is longer than the daytime period, November 28 is determined to be polar night. For simplicity's sake, in table T32, the 10:00 AM to 12:59 AM period is described as the daytime period. However, in the example of FIG. 9 , the 10:00 AM to 12:59 AM period may actually include the sunrise and sunset periods.

[0091] 10 shows a table T41 indicating background image indexes for time periods in Norway in May. In table T41, sunrise time falls in the time period from 3:00 to 3:59, while sunset time falls in the time period from 22:00 to 22:59. Therefore, since the difference between sunrise time and sunset time is one hour or more, table T41 shows an example in which the midnight sun does not exist.

[0092] Also, on the right side of FIG. 10 , as an example of the midnight sun, table T42 is shown, which shows background image indexes for time periods in Norway in June. In this table T42, the sunrise time falls within the time period of 1:00 to 1:59, and the sunrise time period is set to the time period of 0:00 to 2:59. As shown in FIG. 10 , background images "4" to "7" are assigned to the sunrise time period as part of the first image set S1. Furthermore, in table T42, time periods other than the sunrise time period, in this embodiment, the time period from 3:00 to 23:59, are set as daytime time periods. Five background images each of "8," "10," and "11" are assigned to this daytime time period in the third image set S3, and six background images of "9" are assigned. In this way, in the case of the midnight sun, the first image set S1 is displayed during the sunrise time period, and the third image set S3 is displayed during the time periods other than the sunrise time period, which are set as daytime time periods. Furthermore, display of the second image set S2 is prohibited. This is because the sun does not set even at night during the midnight sun, so there is no need to display the second image set S2 related to sunset.

[0093] Furthermore, in table T42, the background image for "4" is the darkest image in the first image set S1. When a user P in the vehicle sees the relatively bright background image for "11" from 23:00 to 23:59 and then the dark background image for "4" from 0:00 to 0:59, the user P will get the impression that the screen has suddenly changed. Therefore, to alleviate this, the background image for "4" from 0:00 to 0:59 may be replaced with a background image for "7" that is brighter than "4." Alternatively, the background image for "4" may be replaced with a background image for "7," and the background image for "5" may be deleted. By assigning background images for "7," "6," and "7" in this order to the time periods of 0:00 to 0:59, 1:00 to 1:59, and 2:00 to 2:59, the display time of the bright background image for "7" may be extended.

[0094] As described above, in the fourth embodiment, the determination of whether a midnight sun is occurring is performed based on location information and date information. If a midnight sun is determined to be occurring, the display of the second image set S2 is prohibited, the first image set S1 is displayed during the sunrise period, and images of the third image set S3 are displayed during periods other than the sunrise period, which are considered daytime periods. Because the sun does not set during the midnight sun, most periods other than the sunrise period are considered daytime periods, where the light intensity is bright and changes little. Therefore, by prohibiting the display of the second image set S2 and displaying the background image of the third image set S3 during the relatively long daytime periods, the amount of data used by the IVI 20 and the meter 30 can be reduced compared to when both the first image set S1 and the second image set S2 are displayed.

[0095] 11 shows table T51, which shows background image indexes for time periods in Norway in August. In table T51, sunrise time falls in the time period from 2:00 to 2:59, while sunset time falls in the time period from 23:00 to 23:59. Therefore, since the difference between sunrise time and sunset time is one hour or more, table T51 shows an example of a non-polar night.

[0096] Also, on the right side of FIG. 11 , a table T52 is shown showing background image indexes for time periods in Norway in December as an example of polar night. In this table T52, the sunset time falls within the time period of 11:00 to 11:59, and the sunset time period is set to the time period of 10:00 to 13:59. As shown in FIG. 11 , background images "12" to "15" are assigned to the sunset time period as the second image set S2. Furthermore, in table T52, the time period other than the sunset time period, in this embodiment, the time period from 14:00 to 9:59, is set as the night time period. In this night time period, two background images "1", seven background images "2", eight background images "3", and three background images "16" are assigned to the fourth image set S4. In this way, in the case of polar night, the second image set S2 is displayed during the sunset time period, and the time period other than the sunset time period is set as the night time period, and the fourth image set S4 is displayed. Furthermore, display of the first image set S1 is prohibited. This is because during the polar night, the sun does not rise all day, so there is no need to display the first set of images S1 related to sunrise.

[0097] As described above, in the fifth embodiment, polar night is determined based on location information and date information. If polar night is determined, the display of the first image set S1 is prohibited, the second image set S2 is displayed during sunset, and images of the fourth image set S4 are displayed during the period other than sunset, which is considered to be nighttime. Because the sun does not rise during the day during polar night, most of the period other than sunset can be considered to be nighttime, when the light intensity is dim and changes little. Therefore, by prohibiting the display of the first image set S1 and displaying the background image of the fourth image set S4 during the relatively long period of nighttime, the amount of data used by the IVI 20 and the meter 30 can be reduced compared to when both the first image set S1 and the second image set S2 are displayed.

Claims

1. A background image display method for a display that displays a time-series of daily scenes that change over time as background images corresponding to the actual time on the display of a control device, comprising: preparing in advance a first image set consisting of a plurality of images in a time series of sunrise time periods including sunrise time; a second image set consisting of a plurality of images in a time series of sunset time periods including sunset time; and a third image set consisting of a plurality of images in a time series of daylight time periods between the sunrise time period and the sunset time period; determining the local sunrise time and local sunset time based on location information and date information; setting the sunrise time period during which the first image set will be displayed based on the local sunrise time; setting the sunset time period during which the second image set will be displayed based on the local sunset time; setting a daylight time period between the two with a variable duration during which the third image set will be displayed; sequentially displaying all images of the first image set during the sunrise time period, sequentially displaying all images of the second image set during the sunset time period, and displaying at least some images of the third image set during the daylight time period.

2. A background image display method for a display as described in claim 1, further comprising: preparing in advance a fourth image set consisting of a plurality of images in a chronological order during a nighttime period between a sunset time period and a sunrise time period; setting a variable-length nighttime period during which said fourth image set is displayed between a sunset time period based on the local sunset time and a sunrise time period based on the local sunrise time; and displaying at least some of the images in said fourth image set during the nighttime period.

3. The background image display method for a display according to claim 1, wherein the display time of each image in said third image set is expanded or contracted in response to the expansion or contraction of said daytime hours.

4. The background image display method for a display according to claim 1, wherein the image in the third image set that is central in time series is preferentially stretched or compressed.

5. The background image display method for a display according to claim 1, wherein the number of images displayed in said third image set is increased or decreased in response to the expansion or contraction of said daytime hours.

6. A background image display method for a display as described in claim 1, wherein a sunrise time period for displaying the first set of images is set based on the local sunrise time, and a sunset time period for displaying the second set of images is set based on the local sunset time.

7. A background image display method for a display as described in claim 2, which determines whether it is a midnight sun based on the location information and the date information, and if it is a midnight sun, prohibits display of the second image set, displays the first image set during sunrise time, and displays images of the third image set during times other than sunrise time as daytime.

8. A background image display method for a display as described in claim 2, which determines whether it is polar night based on the location information and the date information, and if it is polar night, prohibits display of the first image set, displays the second image set during sunrise time, and displays images of the fourth image set during times other than sunset time as night time.

9. A background image display device for a display that displays a time-series of daily scenes that change over time as background images corresponding to actual time on the display of a control device, comprising: a storage unit that stores a first image set consisting of a plurality of images in a time series of sunrise time periods including sunrise time, a second image set consisting of a plurality of images in a time series of sunset time periods including sunset time, and a third image set consisting of a plurality of images in a time series of daylight time periods between the sunrise time period and the sunset time period; a determination unit that determines the local sunrise time and the local sunset time based on location information and date information; and a setting unit that sets the sunrise time period during which the first image set is displayed based on the local sunrise time, sets the sunset time period during which the second image set is displayed based on the local sunset time, and sets a daylight time period with a variable duration during which the third image set is displayed between the two, wherein the display sequentially displays all images of the first image set during the sunrise time period, sequentially displays all images of the second image set during the sunset time period, and displays at least some images of the third image set during the daylight time period.

10. A background image display program for causing a computer connected to said display to execute the background image display method of claim 1.

Images