DISPLAY APPARATUS AND METHOD FOR AUTOMOTIVE VEHICLE

Abstract: In display apparatus and method for an automotive vehicle in which an image display is mounted, a road map data image is stored in a storage medium, a mark representing the present position of the vehicle is superimposed on the road map data image, the road map data image is rotated on an image screen of the image display in accordance with a traveling direction of the vehicle while displaying the road map data image on an image screen of the image display, and a display form of the displayed road map data image is varied between a region of the road map data image which is near to a displayed position at which the vehicle is present and another region thereof which is remote from the displayed position thereof while rotating the road map data image on the image screen of the image display section.

Description: DESCRIPTION DISPLAYAPPARATUSANDMETHODFORAUTOMOTIVEVEHICLE Technical Field The present invention relates to display apparatus and method for an automotive vehicle such as, so-called, car navigation system and method. The present invention, more particularly, relates to a technique for improving a visibility of an image displayed on an image screen of a display. Background Art A Japanese Patent Application First Publication No . Heisei 10-148534 published on June 2, 1998 exemplifies a previously proposed vehicular display apparatus. In the previously proposed vehicular display apparatus disclosed in the above-identified Japanese Patent Application First Publication, in a case where a vehicular steering wheel is steered toward a center of the vehicle in order to turn the vehicle, the image screen of the display is switched to a state in which a visibility of the whole image screen of the display is lowered so that a vehicular driver does not feel troublesome. Disclosure of the Invention; However, since, in the previouslyproposedvehicular display apparatus disclosed in the above-identified Japanese Patent Application First Publication, the visibility of the whole display image screen is modified, there is a possibility that the vehicular driver still feels troublesome. It is, therefore, an object of the present invention to provide display apparatus and method for an automotive vehiclewhichmeet avehiculardriving sense of thevehicular driver while improving a visibility of the displayed image . According to one aspect of the present invention, there is provided a display apparatus for an automotive vehicle, comprising: an image display section; a present positionmeasuring section that measures a present position of the vehicle; a road map storing section that stores a road map data image; a superimpose processing section that superimposes a mark representing the present position of the vehicle on the road map data image to display the road map data image on which the mark is superimposed through the image display section; and display control section that rotates the road map data image displayed on an image screen of the image display section in accordance with a traveling direction of the vehicle and varies a display form of the displayed road map data image between a region of the road map data image which is near to a displayed position at which the vehicle is present and another region of the road map data image which is remote from the displayed position thereof when rotating the road map data image on the image screen displayed on the image display section. This disclosure of the inventiondoes not necessarily describe all necessary features so that the invention may also be a sub-combination of these described features. Brief Description of the Drawings; Fig. 1 is a block diagram representing a structure of a vehicular display apparatus according to the present invention related to each of first, second, third, fourth, fifth, and sixth preferred embodiments. Fig.2 is ablock diagramrepresenting amore detailed structure of vehicular display apparatus related to the first, third, and fourth preferred embodiments. Fig. 3 is a processing flowchart representing a procedure of the vehicular display apparatus in the first preferred embodiment. Figs .4A and 4B are characteristic curves on an image contrast preset in a display form setting table, respectively. Fig.5 is aphotograph representing adisplay example ofadisplayedimageonadisplaywhenthevehiclehas traveled in a straight run. Fig.6 is aphotographrepresenting adisplay example of a displayed image on display when a contrast of road map data image is changed during a rotation of road map. Fig.7 is a photograph of a display example of a road map data image when a brightness of the road map data image is varied during the rotation of road map data image. Fig. 8A is a photograph of a display example of the road map data image when a focus of the road map data image is varied during the rotation of road map data image. Fig. 8B is a photograph of a display example of the road map data image when a contrast of a region of the road map data image which surrounds an arrowedmark representing a present position of the vehicle is raised and that of another region of the road map data which is remote from the displayed arrowed mark is lowered. Fig.8Cis aphotographrepresentingadisplayexample of the displayed image when a saturation of a region of the road map data image which surrounds the arrowed mark is lowered as compared with another region thereof which is remote from the arrowed mark. Fig. 9 is a photograph representing an example of theroadmapdataimageinaformof abird' s eyeviewdisplayed on the display to which the present invention is applicable. Fig. 10 is a photograph representing an example of the displayed road map data image in the form of the bird 1 s eye view to which a contrast process described in the first embodiment shown in Figs.l and 2 is added. Fig. 11 is a detailed block diagram of the vehicular display apparatus in the second preferred embodiment according to the present invention. Fig. 12 is a characteristic graph representing an example of varying the display form according to a circumferential velocity VI and a luminance of an area surrounding the vehicle used in the second embodiment shown in Fig. 11. Fig. 13 is an operational flowchart representing a procedure of vehicular display apparatus in the third preferred embodiment according to the present invention. Fig.14 is aphotographof a displayexample of display representing a road map data image processed in a simplification process carried out in the third embodiment shown in Figs . 1 and 13. Fig. 15 is an operational flowchart representing a procedure of vehicular display apparatus in the fourth preferred embodiment according to the present invention. Fig.16 is aphotographrepresentingadisplayexample of the displayed image of display when a ratio of a road map data image before a rotation of the road map data image to that after the rotation thereof is 10 : 0. Fig.17 is aphotographrepresentingadisplayexample of the displayed image of display when the ratio of the road map data image before the rotation of the road map data image to that after the rotation thereof is 7 : 3. Fig.18 is aphotographrepresentingadisplayexample of the displayed image of display when the ratio of road map data image before the rotation of the road map data image to that after the rotation thereof is 5 : 5. Fig. 19 a photograph representing a display example of the displayed image of display when the ratio of road map data image before the rotation of the road map data image to that after the rotation thereof is 3 : 7. Fig.20 is aphotographrepresentingadisplayexample of the displayed image of display when the ratio of road map data image before the rotation of the road map data image to that after the rotation thereof is 0 : 10. Fig. 21 is an operational flowchart representing a procedure carried out in the vehicular display apparatus in the fifth preferred embodiment according to the present invention. Fig. 22 is a block diagram of the structure of the vehicular display apparatus in the sixth preferred embodiment according to the present invention. Figs. 23, 24, and 25 are integrally a procedure flowchart executed in the vehicular display apparatus of the sixth preferred embodiment shown in Figs. 1 and 22. Fig. 26A is a timing chart representing start and end of a turning of the vehicle. Figs.26B, 26C, and26Daretimingcharts representing start and end of the rotation of each display form varied road map data image. Best Mode for Carrying Out the Invention; Reference will hereinafter be made to the drawings in order to facilitate a better understanding of the present invention Fig. 1 shows a whole configuration of a display apparatus for an automotive vehicle (hereinafter, also referred to as a vehicular display apparatus) related to eachpreferredembodimentaccordingtothepresent invention. As shown in Fig.1, vehicular display apparatus 1 includes: apresent positionmeasuring unit 2 whichmeasures apresent position of the vehicle (hereinafter, also referred to as a host vehicle) ; a GPS (Global Positioning System) antenna 2 which receives GPS signals radiated from a plurality of position measuring satellites; a gyro sensor 4 which measures a traveling direction of the host vehicle; a distance measurement sensor 5 which measures a running distance of the vehicle; a display (corresponding to image display means) 7; and a display controller 6 which controls an image display onto display 7. Present position measuring unit 2 measures an absolute position of the host vehicle on the basis of a position measurement information received from GPS antenna 3. In addition, in a case where the GPS signals cannot be received, the present position of the vehicle is measured using a self-contained navigation (SCN) method based on the position measurement data obtained from gyro sensor 4 and distance sensor 5. It is noted that display 7 may be constitutedbyaliquidcrystal display, present position measuringunit 2 and display controller 7 maybe constituted by a microcomputer and its peripheral circuit. Fig.2 shows a functional block diagram representing a structure of the vehicular display apparatus 1 related to each of first, second, third, fourth, and fifthpreferred embodiments according to the present invention. As shown in Fig. 2, display controller (corresponding to display control means) 6 includes a velocity calculating section 11; an (arithmetically) comparing section 12; a display form adjusting section 13; and a display image data generating section 14. In addition, display controller 6 includes a display form setting table which stores setting data needed when the display form adjusting section 13 adjusts the displayform; and aroadmap data storing section 22 which stores a road map data image placed in a proximity to a running position of the host vehicle. Velocity calculating section 11 detects a circumferential velocity VI at various points of places (given spots) on the roadmap data image displayedon display 7 along with a turn of the vehicle when the vehicular driver steers a vehicular steering wheel to turn the vehicle so that atravelingdirectionofthevehiclemeasuredbypresent position measuring section 2 is changed. In addition, velocity calculating section 11 has a function to calculate a turning angle θ 1 of the vehicle within a predetermined period of time when the traveling direction of the vehicle is changed, as will be described later in each of the third and fourth preferred embodiments. In comparing section 12, a reference value Vref of the circumferential velocity is preset . Comparing section 12 compares the circumferential velocity VI derived by velocity calculating section 11 with reference value Vref to determine whether the circumferential velocity VI is larger than reference value Vref thereof. A signal indicating a result of the determination described above is suppliedto displayformadjustingsection 13. Inaddition, another reference value 0ref of a turning angle of the vehicle with another predetermined period of time is preset in comparing section 12 as will be described later in each of the third and fourth preferred embodiments according to the present invention. Then, comparing section 12 compares the turning angle θ 1 derived by velocity calculating section 11 with reference value #ref. Displayformad ustingsection 13 carries outaproper modification (variation) of a display form of the road map data image displayed on display 7 when comparing section 12 determines that the circumferential velocity VI of the image on display 7 is larger than a reference value Vref of circumferential velocity described above. The display form includes an image contrast, an image brightness, an image saturation, and a simplification (simplifying process) of the displayed image. Display form adjusting section 13 adjusts at least one of display forms of these items on the basis of data stored in display form setting table 21 in such a procedure as will be described later. Furthermore, display form adjusting section 13 has a function to implement a display process such as to superimpose a road map data image after the traveling direction of the vehicle is changed on that before the traveling direction of the vehicle is changed. Display image data generating section 14 carries out a process of generating an image to be displayed on display 7 on the basis of road map data read from road map storing section 22, data on the present position of the vehicle and the traveling direction of the vehicle supplied from present position measuring unit 2 , and data on various kinds of display forms supplied from display form adjusting section 13. It is noted that road map data storing section 22 may be constituted by an external storage medium and driver therefor. Next , an operation of the first preferred embodiment of vehicular display apparatus 1 will be described with reference to a flowchart shown in Fig. 3. At a step ST1, present position measuring section 2 measures the present position of the host vehicle on the basis of data obtained by GPS antenna 3 or by both of distance sensor 5 and gyro sensor 4. At the next step ST2, display image data generating section 14 reads road map data of a surrounding regional area with a point of place at which the vehicle is running as a center f om roadmap data storing section 22. At the next step ST3, display image data generating section 14 superimposes a mark representing the position of the host vehicle on the road map data image. At the next step ST4 , display image data generating section 14 generates the image data to be displayed on display 7. Next , if the vehicular driver steers a steeringwheel of the vehicle to change the traveling direction of the vehicle (Yes at a step ST5) , display image data generating section 14 rotates the road map data image with the position of the vehicle to be displayed as a center so as to adjust the travelingdirectionof thevehicleon display 7 tousually indicate the same direction as the actual traveling direction thereof. At the same time, velocity calculating section 11 calculates rotation velocity at various point of places (various given points) on the road map data image along with the steering operation, namely, circumferential velocities VI . It is noted that circumferential velocities VI can easily be derived on the basis of a rotation velocity of the road map image data and respective distances of the respective points of places to the center of the image (viz . , the position of the vehicle). At a step ST6, comparing section 12 compares the preset reference value Vref of circumferential velocity (Vref is, for example, 50 mm/s (millimeter/second) ) with eachof circumferentialvelocitiesVI calculatedbyvelocity calculating section 11 to determine whether a position (a point of place) on the road map data image at which corresponding magnitude of circumferential velocity VI becomes larger than reference value Vref is present on the image screen of display 7. If Yes at step ST6, namely, the above-described position on the road map data image is determined to be present, display form adjusting section 13 then carries out such a process as to adjust the image contrast along with the rotation of road map data image on the image screen of display 7 at the next step ST7. It is noted that although an adjustment on the contrast, as one example, will herein be explained, the adjustment of brightness, saturation, focus, or a combination of these elements is possible. The adjustment process of the contrast is set in accordance with a characteristic graph stored in display form setting table 21. Fig. 4A shows the characteristic graph representing a relationship between circumferential velocity VI and contrast. As shown in Fig. 4A, at the position at which the corresponding magnitude of circumferential velocity VI which is equal to or lower than 50 mm/s, a high contrast (the same contrast as that in an ordinary display) is maintained. Such a processing as reducing the contrast in the form of a first-order function with respect to an increase in circumferential velocity VI when circumferentialvelocityVI falls in arange between 50 mm/s and 150 mm/s is added. Furthermore, if circumferential velocity VI is in excess of 150 mm/s, such a process as to reduce further the contrast is not carried out. Then, the image to which the adjustment process of the contrast is added is displayed on the image screen of display 7 (at a step ST8 in Fig. 3). Thereafter, the above-described series of processes of steps ST1 through ST8 are repeateduntil an ignition switch of the hostvehicle is turned off (Yes at a step ST9). Fig.5 shows a display example of display 7 when the vehicle (the present position (including the traveling direction) is represented by an arrowed mark in red) is running ordinarily (or normally) . Fig. 6 shows a display example of the image screen of display 7 when the contrast of the road map data image displayed through display 7 is varied when the traveling direction of the host vehicle is changed. As appreciated from Figs .5 and 6 , the road map data image displayed on the image screen of display 7 is adjusted in such a manner that, as the road map data image becomes apart from the displayed position of the vehicle (represented by the arrowed mark), the contrast thereon becomes generally lowered. Hence, when the traveling directionof thevehicleis changedat, forexample, atraffic intersection, a vehicular occupant (including vehicular driver) can avoid a troublesomeness caused by the rotation of the road map data image on the image screen of display 7 so that the visibility of road map data image can be improved. In the first embodiment, the example of setting the relationship between circumferential velocity VI and contrast of road map data image using the characteristic graph as shown in Fig.4A has been explained. However, the present invention is not limited to this. That is to say, as shown in a characteristic graph of Fig. 4B, it is also possibletoreducethecontrastintheformofthefirst-order function as a region of the road map data image becomes remote from the rotation center of the road map data image. In this case, such a comparison process as comparing circumferential velocity VI with reference value Vref of circumferential velocity in the comparing section 12 can be omitted. In addition, in the first embodiment, circumferential velocity VI on each of various points of places is derived and the display form such as the contrast is changed on the basis of a magnitude of circumferential velocityVI . However, the present invention is not limited to this. It is possible to vary the display form on the basis of an angularvelocityAV of each of the various points of places, each distance D of the various points of places from the rotation center, and a magnitude of a visual sense variation rate R. In this case, each lateral axis in the characteristic graphs of Figs. 4A and 4B denotes any one of angularvelocityAV, distance D rom the rotation center, visual sense variation rate R. In addition, in the first embodiment, display form adjusting section 13 adjusts the contrast on the road map data image. However, as another display form, the brightness, the saturation, and focus of the road map data image may be adjusted. Fig. 7 shows a display example of the image screen of display 7 when the brightness of road map data image is adjusted. As shown in Fig.7, with the present position of thevehicle on the image screen of display 7 as the center, as the region of the road map image becomes more remote from the present position of thevehicle on the image screen, the brightness of the road map data image becomes lowered. Even in suchadisplayformas shown inFig.7 , the troublesome feeling that the vehicular occupant gives when the road map data image is rotated can be avoided in the same manner as described above. Furthermore, Fig. 8A shows a display example of adjusting the focus of the road map data image by display form adjusting section 13 in such a manner that an adjacent portion of the rotation center on the road map data image is clearly displayed and, as the region of the road map data image becomes more remote from the rotation center, the image becomes shaded. In the case of the display form of adjusting the focus, the troublesome feeling that the vehicular occupant gives during the rotation of the road map data image can be avoided and the visibility of the image screen of display 7 can be improved. It is noted that Fig.8B shows a display example on the display image screen of display 7 in which the contrast of a region of the road map data image which is near to the present position of the vehicle indicated by the arrowed mark is lowered and that of another region thereof which is remotefromthe centerofrotation (arrowedmarkposition) is raised and Fig.8C shows a display example on the display image screen of display 7 in which the saturation of the remoteregionfromthepositionofthearrowedmarkis lowered than that of the region near to the arrowed mark position. In addition, it is possible not only to vary various display forms concentrically (contrast, brightness, saturation, focus, and so forth) with the present position of the vehicle on the road map data image as the center but also to adjust the display form at a desired portion on the road map data image in such a manner as only an upper portion of the display image screen of display 7 or only a lower portion thereof. In the first preferred embodiment described above, such a series of processes as for a plan view road map data image displayed on the image screen of display 7 has been explained. However, the same series of processes described above are applicable to the road map data image in a form of a bird's eye view (perspective view). Fig.9 shows a display example of the bird' s eye view displayed on the image screen of display 7. As shown in Fig. 9, the region of the road map data image in the form of the bird' s eye view which is near to the present position of the vehicle indicated by the arrowed mark is displayed approximately three-dimensionally. Then, when the traveling direction of the vehicle is changed and the road map data image in the form of the bird' s eye view is rotated, the contrast of the region which is remote from the arrowed mark position (the present position of the host vehicle) is lowered, as shown in Fig. 10. Hence, even in the bird's eye view formedroadmap data image, the troublesome feeling that the vehicular occupant gives during the rotation of the road map data image can be reduced. Next, the second preferred embodiment of vehicular display apparatus 1 will be described below. Fig. 11 shows a block diagram representing the structure of vehicular display apparatus 1 in the second preferred embodiment according to the present invention. As shown inFig.11 , an addition of a luminance sensor 23 is a point of difference fromvehicular display apparatus 1 in the case of the first embodiment shown in Fig. 2. Luminance sensor 23 is a sensor to detect a luminance of a surrounding area of the vehicle. In this embodiment, the display form of the road map image data on display 7 is adjusted on the basis of detected data of the luminance sensor 23. In addition. Fig. 12 shows characteristic graphs representing each relationship between circumferential velocityVIoftherotatingroadmapdataimageandaluminance (it is noted that the contrast, the saturation, or focus may be adopted in place of the luminance) of the road map data image displayed on display 7 and which are set in display form setting table 21. Characteristic graphs representing the relationship between the luminance and circumferential velocity VI are different between that in the case where the surrounding area of the vehicle is bright and that in the casewhere the surrounding area of thevehicle is dark. That is to say, when the luminance of the surrounding area of the vehicle is determined to be equal to or larger than a predetermined level, the brightness is set to be varied gradually like the first-order function in the range of circumferential velocity VI from 50 to 150 mm/s as shown by a characteristic curve of SI inFig.12. When the luminance of the surrounding area of the vehicle is lower than the predetermined level, the brightness is set to be varied abruptly like the first-order function in the range of circumferential velocity VI from 50 to 100 mm/s, as shown by another characteristic curve of S2 in Fig. 12. In the second embodiment described above, in such a case where the luminance of the surrounding area of the vehicle is low as a night time, rainy weather, or run in a tunnel at which the vehicular occupant is particularly easy to feel troublesome, a rate of variation in the brightness with respect to circumferential velocity VI is set tobe large . Hence, the troublesomefeelingcanbereduced and the visibility of display 7 can be improved. In addition, in such a case where the luminance of the surrounding area is bright as a daytime, the brightness is set to be varied moderately with respect to circumferential velocity VI so that a required information can accurately be recognized. Next, the third preferred embodiment of vehicular display apparatus 1 according to the present invention will be described below. In the third embodiment, the road map data image becomes simplified and displayed as the region of the road mapdataimagebecomesmoreremotefromthecenterofrotation along with the rotation of the road map data image on the image screen of display 7 so that the troublesome feeling that the vehicular occupant gives can be reduced. The structure of the third embodiment is the same as the block diagram shown in Fig. 2 of the first embodiment described above . The operation of vehicular display apparatus 1 in the third embodiment will be explained with reference to theblockdiagramshowninFig.2 andanoperational flowchart shown in Fig. 13. First, at a step ST11, present position measuring unit 2 detects a run position of the vehicle. Then, at a step ST12, display controller 6 determines whether the ignition switchis turnedoff. IfNo at step ST12 , theroutine goes to a step ST13. At step ST13, display image data generating section 14 of display controller 6 carries out such a process as to superimpose and display the present position of the vehicle (the arrowed mark) on the region of the roadmap data stored in road map data storing section 22 which surrounds the point of place at which the vehicle is running. Next, at a step ST14, velocity calculating section 11 carries out such a process as to derive a turning angle θ 1 of the vehicle within a predetermined period of time on the basis of data on the present position of the vehicle obtained by present position measuring unit 2. Then, at a step ST15, comparing section 12 compares the turning angle θ l with the preset reference value θref in the comparing section 12 to determine whether θ 1 > θ ref . If θ 1 > θref (Yes) at step ST15, the routine goes to a step ST16. If θl ----- - ref (No), the routine jumps to step ST12. At step ST16, display form adjusting section 13 carries out such a process as to simplify the road map data image for the region of the roa map data image which is equal to or longer than a predetermined distance value from the center of rotation and to display the other region of the road map data image which is shorter than the predetermined distance value from the rotation center normally without the simplification process. Then, at the next step ST17, the generated image data is displayed on the image screen of display 7. Fig. 14 shows a display example representing an example of the road map data image which has been processed under the simplification process as described in the third embodiment . As appreciated from Fig. 14, for the region of the road map data image which surrounds the displayed present position of the vehicle (arrowed mark, viz . , which provides the center of rotation on the road map data image) , the road map data image is displayed normally in details and for the other region of the road map data image which is remote from the center of rotation by the predetermined distance value, the road map data image is simplified and displayed. The meaning of this term of simplified is that the detailed road map information is omitted. Hence, the troublesome feeling that the vehicular occupant gives when the road map data image is rotated can be reduced and the visibility of the image screen on display 7 can be improved. Next, the fourth preferred embodiment of vehicular display apparatus 1 will be described below. In the fourth embodiment, along with the rotation of the road map data image on the image screen of display 7 , the image before the rotation and that after the rotation are superimposed together and displayed and a ratio of this superimposition is varied gradually so that the road map data image on display 7 is rotated without giving the vehicular occupant the troublesome feeling. The structure of vehicular display apparatus 1 in the fourth embodiment is the same as the block diagram of Fig. 2. Fig. 15 shows a processing flowchart of the fourth preferred embodiment for explaining the operation of vehicular display apparatus 1 in the fourth embodiment. At a step ST21, present position measuring unit 2 detects the running position of the vehicle (it is natural that the traveling direction thereof is measured) . At a step ST22, displaycontroller 6 receives the ignition switch position information to determine whether the ignition switch is turned off. If the ignition switch is not turned off (No) at step ST22, the routine goes to a step ST22. If the ignition switch is turned off (Yes) at step ST22, the routine is ended. At step ST23, display image data generating section 14 of display controller 6 carries out such a process as to superimpose the present position of the vehicle (arrowed mark) on the region of the road map datawhichsurrounds therunningpointofplaceof thevehicle stored in road map data storing section 22 and displays the arrowed mark superimposed road map data image on the image screen of display 7. Then, at the next step ST24,velocity calculating section 11 derives the rotation angle θl of the vehicle within the predetermined period of time on the basis of the data on the present position of the vehicle obtained by present position measuring unit 2. Then, the routine goes to a step ST24. At step ST24, comparing section 12 comparesreferencevalue θrefpreset incalculatingsection 12withrotationangle θ 1 of thevehicle to determinewhether θ l > ( ref. If θ l > θref (Yes) at step ST25, the routine goes to a step ST26. At step ST26, display form adjusting section 13 carries out such a process as to turn a count value of L indicating a level of an image processing to 0 (L = 0) . Then, the image of level L is displayed on image screen of level L at the next step ST27. It is noted that level L is a level indicating a magnitude of the superimposition of two images, when L = 0, the image to be displayed is the whole road map data image before the traveling direction of the vehicle is changed, and, when L = LI, the image to be displayed is the whole road map data image after the traveling direction of the vehicle is changed. Suppose now that LI = 5. In this case, when L = 0, an superimposition ratio of the road map data image before the traveling direction of the vehicle is changed to that after the traveling direction thereof is changed is 10 : 0. When L = 1, the same ratio indicates 7 : 3. When L = 2, the same ratio indicates 5 : 5. When L = 3, the same ratio indicates 3 : 7. When L = 4, the same ratio indicates 0 : 10. Next, at a step ST27, display form adjusting section 13 of display controller 6 carries out such a process as to generate the image of level L (at this time, L = 0). Then, at the next step ST28, the generated road map data image on the image screen of display 7. Thereafter, the value of L is incremented by one (L = L + 1) at a step ST29. The above-described process from step ST27 to step ST29 is repeated until L = LI at a step ST30. If L = LI (in this case, LI = 5) at step ST30 (Yes), the routine jumps to step ST24 and the same series of processes of steps ST24 to ST30 are repeated if θ 1 > θ ref at step ST25. Figs. 16, 17, 18, 19, and 20 show series of display examples of the image screen of display 7 for explaining a variation pattern of the road map data image in the case of the display form adjustment carried out in the fourth embodiment described above. In details. Fig. 16 shows the result of image processing when L = 0 (viz., the superimposition ratio of the road map data image before the rotation thereof to that after the rotation thereof is 10 : 0 ) . Fig. 17 shows the result of image processing when L = 1 (the ratio thereof is 7 : 3). Fig. 18 shows the result of image processing when L = 2 (the same ratio is 5 : 5). Fig. 19 shows the result of image processing when L = 3 (the same ratio is 3 : 7). Fig. 20 shows the result of processing when L = 4 (the same ratio is 0 : 10). As appreciated from Figs. 16 through 20, the image is displayed on display 7 in such a manner that the superimposition ratio between two images (image before the rotation thereof and that after the rotation thereof) is gradually varied while the turn of the vehicle is started and, then, the turn of the vehicle is ended. As described above, in the fourth embodiment of vehicular display apparatus 1 according to the present invention, when the traveling direction of the vehicle is changed, the superimpositionbetweentheroadmapdataimage before and after this direction change is carried out and the superimposition ratio is set to be gradually varied. Therefore, the vehicular occupant can visually recognize the roadmapdataimage displayedon display 7 withapleasant feeling. Consequently, the troublesome feeling that the vehicular occupant gives can be relieved. Next, the fifth preferred embodiment of vehicular display apparatus 1 will be described below. In the fifth embodiment, such a process as to rotate the road map data image is carried out in such a manner as to synchronize the rotation of the road map data image displayed on the image screen of display 7 with a variation of a field of viewfor avehicular forward zone of the vehicle that the vehicular occupant visually recognizes. Hence, the road map data image can be displayed without giving an unpleasant feeling to the vehicular occupant . The structure of vehicular display apparatus 1 in the fifth embodiment has the same structure as the block diagram of Fig. 1 described above. Fig.21 shows a processing flowchart carried out in the fifth embodiment. The operation of the fifth embodiment will be described with reference to Fig. 21. In Fig.21, display controller 6 determines whether the ignition switch of the vehicle is turned off at a step ST31. At a step ST32, the present position measuring unit 2 measures the present position of thevehicle and traveling direction thereof. At a step ST33, display controller 6 superimposes the arrowed mark representing the present position of the vehicle and direction thereof on the region of the road map data image which surrounds the running position of the vehicle and generates the image synthesized with character data representing a name of place or so forth. Then, at the next step ST34, the display controller 6 carries out such a process as to display the generated image on display 7. Next, at a step ST35, display controller 6 carries out such a process as to calculate the traveling direction (vehicular direction) of the vehicle on the basis of the data on the traveling direction of the vehicle obtained by gyro sensor 4. At a step ST36, display controller 6 determines whether a magnitude of the turning angle Δ θ of the vehicle for a predetermined period of time is larger (wider) than reference value θref preset in calculating section 12. If | Δ θ | > -9 ref (Yes) at step ST36, the routine goes to a step ST37. At step ST37, display controller 6 carries out such a process as to rotate the road map data image displayed on display 7 by the angle of Δ θ in a reverse direction to the turning direction of the vehicle. At this time, since the turning angle is measured on the basis of the data derivedby gyro sensor 4 , the display image onto display 7 can be generated at an earlier timing than such as a process as to read a new road map data image and as to synthesize the characters. Hence, the road map data image can be rotated in synchronization with the turn of the vehicle. Then, the image treated under the image processing is addedwith the process of varying appropriately the image contrast, brightness, saturation, and focus during the rotation of the road map data image and, thereafter, the image processed road map data image is displayed on the image screen of display 7 at steps ST38 and ST39. As described above, in the fifth embodiment, when the traveling direction of the vehicle is changed, the rotation of the roadmap data image to be displayed on display 7 is synchronized with the field of view for the actual vehicular forward zone that the vehicular occupant visually recognizes. The vehicular occupant can visually recognize the roadmap data image displayed on display 7 without giving the unpleasant feeling. Next, the sixth preferred embodiment of vehicular display apparatus 1 according to the present invention will be described below. In the sixth embodiment, it is possible to adjust the rotation of the road map data image to be displayed ondisplay7 onthebasis ofapredicteddataderivedaccording to a result of such a prediction as a traveling route of the vehicle. Fig. 22 shows a block diagram representing the structure of vehicular display apparatus in the sixth preferred embodiment. As appreciated from Fig. 22, vehicular velocity display apparatus 1 includes: present position measuring unit 2, GPS antenna 3, gyro sensor 4, distance sensor 5, display controller 6 , and display 7 in the same way as the vehicular display apparatus shown in Fig. 1. In the sixth embodiment, a winker sensor 31 to detect a drive state of an winker of the vehicle and a vehicular velocity sensor 32 to detect a velocity of the vehicle. The operation of vehicular display apparatus 1 in the sixth preferred embodiment will be described with reference to a series of operational flowcharts shown in Figs. 23 through 25. Present position measuring unit 2 shown in Fig. 22 measures the position of the vehicle on the basis of data obtained from the measuring satellites through GPS antenna 3 andthedataof thetravelingdirectionandrunningdistance of the vehicle obtained from gyro sensor 4 and distance sensor 5. Next, when the vehicular driver inputs a destination to which the vehicle is to be reached on display controller 6at astepST52. At astepST53, displaycontroller 6 carries out such a process as to calculate a guide route to guide the vehicle from the present position to the destination. Then, the image display processing is carried out with a count value N set as N = 0 at a step ST54, the count value N representing a level of the image processing. Then, at a step ST55, the image processing of level of N = 0 is carried out and the image processed road map data image is displayed. It is noted that the display image, at this time, is MO. Next, a timer (not shown) provided within display controller 6 is reset at a step ST56. The present time T is set as T = 0. Display controller 6 determines whether the winker of the vehicle is presently operated at a step ST57 from a signal of winker sensor 31. If the winker is being operated (Yes at step ST57), the routine goes to a step ST58. At step ST58, display controller 6 determines whether a traffic intersection is present in the traveling direction of the vehicle on the basis of data on the guide route. If the traffic intersection is present (Yes at step ST58 ) , the routine goes to a step ST59. Display controller 6 carries out such a process as to estimate a road to which the vehicle turns right or left. Next, at a step ST60, display controller 6 estimates the position of thevehicle and direction thereof at a future time Tl after an elapse of a predetermined period of time from the present time. At a step ST61, display controller 6 carries out such a process as to derive the road map data image at the time of Tl . It is noted that the level of image processing at a time Tl is Nl and the image to be displayed on display 7 is Ml. Display controller 6 compares road map data image MO displayed on display 7 with road map data image Ml at a future time Tl (step ST62). When the vehicle is turned at an ordinary velocity, display controller 6 determines whether a position of the road map data image at which the corresponding circumferential velocity VI of road map data image is larger than reference value Vref (for example, Vref = 50 mm/s) at a step ST63. Consequently, if display controller 6 determines that the position of the road map data image at which circumferential velocity VI is larger than reference value Vref (No) at step ST63 is present, the routine goes to a step ST64. At step ST64, display controller 6 determines whether image processing level N is 0 (N = 0) . In this case, since N = 0 (Yes at a step ST64), the routine jumps to a step ST73. At step ST73, display controller 6 carries out such a process as to display image Ml at a time point at which the present time T has reached to the time Tl. Thus, display controller 6 calculates the present position and traveling direction of the vehicle at a step ST75. If an engine of the vehicle is turned off (No at a step ST76), then, the processing is repeated from a step ST56. That is to say, if circumferential velocity VI on a future road map data image is smaller than reference value Vref, display controller 7 does not carry out such aprocess as to variably modifythedisplayformsuchas theimagecontrastbutcarries out such a process as to display image Ml corresponding to a time point at which it reaches to time point Tl. On the other hand, it is predicted that the position of the roadmap data image at which circumferential velocity VI of road map data image is larger than reference value Vref (VI > Vref at step ST63), the routine goes to a step ST68. At step ST68, if image processing level N has reached to image processing level Nl at time point Tl (Yes at step ST68) , the routine goes to a step ST72. At step ST72, such a process as to add display image Ml at time point Tl to image processing level Nl is carried out. Thereafter, when the time has reached to Tl (Yes at step ST73), display controller 6 displays display image Ml on display 7 at a step ST74. At a step ST75, display controller 6 calculates the present position and traveling direction of the vehicle. Unless the engine is turned off (No at step ST76) , the routine jumps to and returns to step ST56. In this state, since the time has reached to Tl and the vehicle has ended to turn the intersection. No is an answer at step ST63. If No at step ST63, the routine goes to step ST64. Since, at this time, image processing level " N " is N = Nl (No at step ST64), the routine goes to a step ST65. At step ST65, image processing level is decremented by one (N = N - 1) . Then, at a step ST66, such an image processing as contrast adjustment is carried out . At the next step ST67, the image display is carried out. Then, at a time point at which image processing level " N " is N = 0, the road map data image at the time point Tl ( ewlyset timeTl) is displayed (stepST74) . Inaddition, if the engine is turned off (Yes at a step ST76), the processing shown in Figs. 23, 24, and 25 is ended. As described above, in a case where at future time point Tl, it is predicted that the position on the road map data image at which corresponding circumferential velocity VI of road map data image is larger than reference value Vref, such a process can be carried out as to relieve the troublesome feeling given to the vehicular occupant bypreviously adjusting the contrast, brightness, and focus on the road map data image before the time has reached to time tl . The road map data image displayed on display 7 can be modified in more natural sense of feeling. Consequently, the visibility of the image screen of display 7 for the vehicular driver can remarkably be improved. In vehicular display apparatus in the sixth embodiment described above, the guide route can be derived from the present position of the vehicle and from the data on the destination and winker sensor 31 and vehicular velocitysensor32 canbeusedtoestimatewhetherthevehicle is to turn the intersection at a future time Tl. Therefore, both of timings at which the vehicle has turnedinresponse to the steeringoperationbythevehicular driver and at which the road map data image on display 7 can appropriately be adjusted. Figs.26A, 26B, 26C, and 26D show explanatory views representing rotational timings of the vehicular turn and road map data image. Fig.26Ashowsatimingchartrepresentingavehicular turn and rotation timing of rotation of roadmap data image. Figs.26B, 26C, and26Daretimingchartsrepresenting various timing charts representing various timing patterns when the road map data image is rotated. As shown in Figs .26A, thevehicle starts the turning at a time point of tl and ends the turning at a time point of t2. In the example shown in Fig. 26B, the timings of the rotation start and rotation end are synchronized with the turning of the vehicle. In addition, the image processing is added to the road map data image at a time Rl immediately before the start of rotation on the road map data image and the contrast adjustment and brightness adjustment are carried out. At a time R2 immediatelyafter the endof rotation, thecontrast andbrightness arereturned to original states . In the example of Fig. 26C, the start timing of rotation of the road map data image is synchronized with the turn of the vehicle and the image processing is added to the road map data image at a time R3 immediately before the start of the turning (rotation) of the road map image. In addition, at a time point of t3 slightly immediately before the time point t2 which is a time point at which the turn of the vehicle is ended, the rotation of the road map data image is ended. At a time R4, the road map data image under the image processing is returned to the original state. In the example of Fig.26D, the image processing is started synchronizing the time point tl at which the turn of the vehicle is started and, after the elapse of the time R5, the road map data image is rotated. In addition, such aprocess as to return theroa map data image to the original state is carried out at the time point t2 at which the turn of the vehicle is ended. Then, as shown in Fig.26B, in a case where the timing at which the start of turn of the vehicle is made coincident with that at which the start of rotation of the road map data image and that at which the turn of the vehicle is ended made coincident with that at which the end of rotation of the road map is ended, respectively, the turn of the vehicle is made coincident with the rotation of the road map data image. Thus, the unpleasant feeling that the vehicular occupant gives is reduced and it is suitable when the traveling direction of the vehicle is varied along the path. In addition, since, in the case of Fig.26C, the road map data image is switched to the display for a straight run at a time point at which the turning of the vehicle is substantially ended in such a case when the vehicle turns right orleft onthetraffic intersection. Hence, itbecomes possible for the vehicular driver to anticipate the subsequent travelingdirection. Consequently, thedisplay method shown in Fig.26C is suitable when the vehicle turns left or right at the traffic intersection. In either the case of Fig. 26D or Fig. 26C, the display image on display is changed to that used for the rotation there of and road map information quantity on the display image is reduced. Hence, the vehicular driver's attention is not paid to the displayed image on display 7 more than necessary. Consequently, a driving safety at the vehicular run on any traffic intersection can be improved. It is noted that, in the case of Fig. 26D, the display of road map data image is switched in synchronization with the actual start or end of the turn of the vehicle. Hence, it is unnecessary to predict the future traveling direction of the vehicle. The entire contents of Japanese Patent Application No. 2000-346694 (filed in Japan on November 14, 2000) are herein incorporated by reference. Modifications and variations of the embodiments described above will occur to those skilled in the art in the light of the above teachings . The scope of the invention is defined with reference to the following claims. INDUSTRIAL APPLICABILITY; The present invention relates to the display apparatus and method for the automotive vehicle such as, so-called, car navigation system and method, in which the roadmap data image whichmeets the vehicular driver' s drive eeling of the vehicle can be displayed and the visibility of display can be improved. Basically, in the vehicular display apparatus according to the present invention, when the road map data image is rotated along with the turn of the vehicle on the image screen of display, the display form is modified in such a manner that the display form on the region of the road map data image which is near to the displayed present position of the vehicle is made different from that on the other region thereof which is remote from the displayed present position of the vehicle.

Claims: CLAIMS 1. A display apparatus for an automotive vehicle, comprising: an image display section; a present position measuring section that measures a present position of the vehicle; a road map storing section that stores a road map data image; a superimpose processing section that superimposes a mark representing the present position of the vehicle on the road map data image to display the road map data image on which the mark is superimposed through the image display section; and display control section that rotates the road map data image displayed on an image screen of the image display section in accordance with a traveling direction of the vehicle and varies a display form of the displayed road map data image between a region of the road map data image which is near to a displayed position at which the vehicle is present and another region of the road map data image which is remote from the displayed position thereof when rotatingtheroadmapdataimageonthe image screendisplayed on the image display section. 2. A display apparatus for an automotive vehicle, comprising: an image display section; a present position measuring section that measures a present position of the vehicle; a road map storing section that stores a road map data image; a superimpose processing section that superimposes a mark representing the present position of the vehicle on the road map data image to display the road map image on which the mark is superimposed through the image display section; and a display control section that rotates the road map data image displayed on an image screen of the image display section in accordance with a traveling direction of the vehicle and displays a region of the road map data image which is near to a displayed position at which the vehicle is present in a display form of a video image clearer than another region of the road map data image which is remote from the displayed position thereof, when rotating the road map data image on the image screen displayed on the image display section. 3. A display apparatus for an automotive vehicle, comprising: an image display section; a present position measuring section that measures a present position of the vehicle; a road map storing section that stores a road map image; a superimpose processing section that superimposes a mark representing the present position of the vehicle on the road map data image to display the road map data image through the image display section; and a display control section that rotates the road map data image displayed on an image screen of the image display section in accordance with a traveling direction of the vehicle and controls an image displayed on the image display section, the display control section comprising: velocity calculatingsectionthat calculates oneofacircumferential velocity thereof at least one given spot of place on the displayed image screen and an angular velocity thereof on the basis of a turning velocity of the vehicle detected by the present vehicle position measuring section and a display magnification displayed on the image screen of the image display section; and a display form adjusting section that adjusts a display form of the displayed image screen of the image display section according to a magnitude of at least one of the circumferential velocity and the angular velocity calculated by the velocity calculating section. 4. A display apparatus for an automotive vehicle, as claimedin claim 1 , further comprisingadisplayform setting table storing a variation characteristic of the display form and wherein the display control section adjustably varies the display form on the image screen of the image display section on the basis of thevariation characteristic preset in the display form setting table. 5. A display apparatus for an automotive vehicle, as claimed in claim 4 , wherein the variation characteristic in the display form setting table is preset with any one of the angular velocity, circumferential velocity, a distance from a center of the rotation of the road map data image and a visual sense variation rate as a parameter. 6. A display apparatus for an automotive vehicle, as claimed in claim 1, wherein the display form is at least one of image contrast, brightness, saturation, and focus. 7. A display apparatus for an automotive vehicle, as claimed in claim 1, wherein, when rotating the road map data image displayed on the image screen of the image display section, the display control section controllably displays the road map data image on the image screen of the image display section in such a manner that contents of the road map data image in the region of the road map data image which is near to the displayed position at which the vehicle is present are displayed in details and the contents thereof in the other region thereof which is remote from the position thereat are displayed in a simplification form. 8. A display apparatus for an automotive vehicle, as claimed in claim 7, wherein the display control section determines whether the other region of the road map data image is to be displayed in the simplification form with any one of an angular velocity of the rotating road map data image, a circumferential velocity of at least a given spot on the other region, a distance of the given spot from a rotation center thereof, and a visual sense variation rate as a parameter. 9. A display apparatus for an automotive vehicle, as claimed in claim 1, wherein the display control section varies the display form in such a manner as to superimpose the road map data image after the traveling direction of thevehicle is changedonthat before the travelingdirection of the vehicle is changed when the direction of the vehicle is changed to rotate the road map data image and to vary gradually a superimposition ratio of the roadmap data image after the traveling direction of the vehicle is changed to the road map image data before the road map data image is changed as the time has passed from 10 : 0 to 0 : 10. 10. A display apparatus for an automotive vehicle, as claimed in claim 1, wherein the display control section varies the display form in such a manner as to synchronize a rotation of a field of view in a driving direction of the vehicle with that of the road map image data for the road map image to be displayed on the image screen of the road map data image. 11. A display apparatus for an automotive vehicle, as claimed in claim 1, wherein the display control section comprises a vehicular traveling route direction predicting section that predicts a direction of a traveling route of the vehicle andwherein, when the direction of the traveling route of the vehicle is varied through an angle equal to or wider than a predetermined angle, the display control section rotates the road map data image with the image of the vehicle as a center on the basis of a predicted data on the direction of the travelingroute of thevehiclevaried through an angle equal to or wider than the predetermined angle. 12. A display apparatus for an automotive vehicle, as claimed in claim 11, wherein the vehicular traveling route direction predicting section predicts the direction of the forwarding route of the vehicle on the basis of at least one of the following data: (a) a comparison data comparing the present traveling direction of the vehicle read from the road map data image with a forward bend situation of the present traveling direction; (b) a data on a preset guide route; and (c) a data on a winker operation of the vehicle. 13. A display apparatus for an automotive vehicle, as claimed in claim 11, wherein the display control section varies the display form of the displayed image screen at an earlier timing than a turning start timing of the vehicle. 14. A display apparatus for an automotive vehicle, as claimed in claim 11, wherein the display control section returns the display form of the displayed image screen on the image display section to an original state at a time point earlier than a timing at which the vehicle has ended a turning. 15. A display apparatus for an automotive vehicle, as claimed in claim 11, wherein the display control section varies the display form of the displayed roadmap data image on the image screen of the image display section after a timing at which the vehicle starts to turn and returns the varied display form to the original state after a timing at which the vehicle has ended the turning. 16. A display apparatus for an automotive vehicle, comprising: image display means; present position measuring means for measuring a present position of the vehicle; road map storing means for storing a road map data image; superimpose processing means for superimposing a mark representing the present position of the vehicle on the road map image to display the road map data image on which the mark is superimposed through the image display section; and display control means for rotating the road map data image displayed on an image screen of the image display section in accordance with a traveling direction of the vehicle and for varying a display form of the displayed road map data image between a region of the road map data image which is near to a displayed position at which the vehicle is present and another region of the road map data image which is remote from the displayed position thereof when rotating the road map data image on the image screen displayed on the image display section. 17. A display method for an automotive vehicle, comprising: providing an image display section; measuring a present position of the vehicle; storing a road map data image; superimposing a mark representing the present position of the vehicle on the roadmap data image to display the road map data image on which the mark is superimposed through the image display section; rotating the road map data image on an image screen of the image display section in accordance with a traveling direction of the vehicle while displaying the road map data image on an image screen of the image display section; and varying a display form of the displayed roadmap data image between a region of the road map data image which is near to a displayed position at which the vehicle is present and another region of the road map data image which is remotefromthe displayedpositionthereofwhile rotating the road map data image on the image screen of the image display section. 18. A display apparatus for an automotive vehicle, as claimed in claim 2, wherein the display control section varies the display form in such a manner as to synchronize a rotation of a field of view in a traveling direction of the vehicle with that of the road map image data for the road map image to be displayed on the image screen of the road map data image. 19. A display apparatus for an automotive vehicle, as claimed in claim 3, wherein the display control section comprises avehicular traveling route direction predicting section that predicts a direction of a traveling route of the vehicle andwherein, when the direction of the traveling route of the vehicle is varied through an angle equal to or wider than a predetermined angle, the display control section rotates and displays the road map data image with the imageof thevehicleas acenteronthebasis ofapredicted data on the direction of the traveling route of the vehicle varied through an angle equal to or wider than the predetermined angle.

Inventors: HIJIKATA SHUNSUKE, HIRAO AKINARI, KATO KAZUHITO, KITAZAKI SATOSHI, NAKAJI YOSHIHARU, HIJIKATA, SHUNSUKE, HIRAO, AKINARI, KATO, KAZUHITO, KITAZAKI, SATOSHI, NAKAJI, YOSHIHARU
Applicants: HIJIKATA SHUNSUKE, HIRAO AKINARI, KATO KAZUHITO, KITAZAKI SATOSHI, NAKAJI YOSHIHARU, NISSAN MOTOR, HIJIKATA, SHUNSUKE, HIRAO, AKINARI, KATO, KAZUHITO, KITAZAKI, SATOSHI, NAKAJI, YOSHIHARU, NISSAN MOTOR CO., LTD.
Application year: 2001
Main classification: G01C21
IPC codes: G01C21, G08G1, G09B29