Method for preparing encoded geoimage data

The present invention relates to a method for supplying encoded geographic image data from a server unit to at least one navigation receiving module. Here, the geographical area is provided by unencoded geographic image data stored in the server unit, and at least one wireless communication interface is provided between the server unit and at least one navigation receiving module.

Navigation systems have become more and more popular in recent years. Navigation systems are often fixedly embedded in the vehicle or retrofitted as a mobile navigation system. Such a navigation system has at least one display unit in addition to a navigation receiving module for receiving position and / or speed signals from the "Global Positioning System (GPS)". On this display unit, a map portion based on a vector graphic, for example, a map portion of a topographic map or a city map is advantageously displayed. Here, advantageously, the map portion where the object connected to the navigation receiving module currently exists is shown. In addition, from the received GPS position signal, in addition to the current position information, direction information and / or velocity information is also derived, and in some cases, a map shown or shown on another display unit. It is superimposed on the part.

The map data required to generate a map portion on the display unit is often stored on an interchangeable data storage medium, such as a DVD (Digital Video Disc). In this case, the interchangeable data storage medium includes all map data associated with indicating the closed geographic area of an individual country or area. Based on the position information obtained by the navigation receiving module, the map data regarding the map portion to be displayed is selected from the map data and displayed on the display unit. For example, the map data shown based on the vector graphic has a sufficiently high resolution in this case. This gives the user of the navigation system a good impression of the mileage or the path to be taken.

In future navigation systems, the display of geographical image data, that is, so-called "geographic image data", is planned in addition to the above-mentioned navigation information. Such geographic image data relates to aerial image recordings of a given geographic area on the surface of the earth formed by sanitary units. This record is available in the navigation system and is displayed on the display unit, for example, in addition to the map data on a regular basis. This allows the user to obtain additional information.

However, displaying such geographic image data on the monitor of the navigation system requires processing of the data, and in particular, the data format needs to be adapted to each configuration of the display unit provided in the navigation system. is there. Such known navigation systems primarily use stationary geographic image data. Immediate supply of current geographic image data to the navigation receive module of a navigation system (eg, real-time supply or supply with only a slight time delay) is not feasible with known systems. Real-time supply often yields to very large amounts of data. This is the amount of data that should be transmitted from, for example, the central server unit to the distributed navigation receiving modules within a very short time. The transmission capacity of the wireless communication interface currently available is not sufficient for this.

In order to reduce the amount of data to be transmitted, a large number of various data coding methods, particularly image data coding methods, are known from the prior art. Such an image data coding method skillfully uses, for example, individual specifications of image content. This enables almost lossless coding of image data. For this purpose, the image content is analyzed, individual image areas are assigned to different data groups, and different encodings are applied to the different data groups. In detail, this coding is performed so as to enable the highest possible display of the image represented by the coded image data. Therefore, known coding methods use different coding depths (Kodierungstiefen), and in particular, the areas where quality loss is tolerated, that is, the image data that reproduces the human face, is coded higher than the image information about the background. It is coded by depth.

Starting from the prior art described above, an object of the present invention is to provide a method of supplying encoded geographic image data from a server unit to at least one navigation receiving module. This method enables the immediate supply of geographic image data.

The above-mentioned problem is solved by the configuration described in the feature portion of claim 1, starting from the feature of the superordinate concept of claim 1.

An important aspect of the method according to the invention is that at least one location information is transmitted from the navigation receive module to the server unit. Then, within the server unit, the expected area is selected from the geographic area, depending on the location information to be transmitted, and the uncompressed first geographic image data that reproduces the selected expected area is Desired. The uncompressed first geographic image data is then compressed within the server unit, and the compressed first geographic image data is transmitted from the server unit to the navigation receive module via at least one wireless communication interface. Will be done. Advantageously, the method of the present invention can significantly reduce the data volume to be transmitted, which makes it possible to immediately supply geographic image data to the navigation system. This saves both the transmission volume and the transmission time. Since the amount of data is reduced, it is possible to additionally update the transmitted geographic image data frequently.

Particularly advantageously, in addition to the position information, the direction information and / or the velocity information indicating the current motion direction of the navigation receiving module is transmitted, and the expected region is obtained depending on this. The expected area here indicates a geographical area. This geographical area contains the current location of the subject connected to the navigation system, and the subject takes into account the direction of motion and / or the velocity of motion transmitted within this area for the next few minutes. Exists.

Further, advantageously, a buffer region containing this anticipation region is required in addition to the anticipation region in which the first geographic image data is encoded at a very high coding depth. Here, the second geographic image data assigned to this buffer region is advantageously encoded with an average coding depth. The remaining third geographic image data in the geographic area is coded at a very low coding depth. In this way, the geographic image data is advantageously transmitted with different coding qualities, depending on the probability of use in the navigation system.

Another advantageous embodiment of the method according to the invention is set forth in the dependent claims.

Hereinafter, the present invention will be described in detail with reference to the drawings according to examples.

<figref num="1">For example, a schematic block schematic of a system that supplies compressed geographic image data.</figref><figref num="2">For example, a schematic block schematic of a navigation system</figref><figref num="3">For example, the division of the geographical area into individual navigation parts and their different coding depths.</figref>

In FIG. 1, for example, a schematic block circuit diagram shows a system S for recording geographic image data GBD (Geobild daten). This system S has at least one, advantageously centralized server unit SU. This server unit can be connected to the sanitary unit SAT via at least one air interface LS and to the navigation system NS via at least one wireless communication interface KS.

Figure 1 shows, for example, two sanitary units SAT. Through these sanitary units, unencoded geographic image data GBDs of a given geographic area B, eg, a country or area, are created and transmitted to the server unit SU via the air interface LS. Geographical area B is, for example, 0.1 to 1000 km²Includes the area portion of the size of.

The server unit SU has a processor unit PU and at least one storage unit MU. Advantageously, the unencoded geographic image data GBD of the geographic region B is stored in this storage unit. The processor unit PU is configured to execute the control routine and the evaluation routine SAR. Through these, in particular, the processing of unencoded geographic image data GBD stored in the storage unit MU or currently received from the hygiene unit SAT, particularly encoding, is performed. The encoded geographic image data GBD'is stored in the storage unit MU in the same manner, for example.

In an advantageous embodiment, the image recording of geographic area B, created via the sanitary unit SAT, is created at the highest resolution possible. This results in a large amount of uncoded geographic image data GBD. However, this allows accurate reproduction of the details of geographical area B.

FIG. 1 shows, for example, a mobile navigation system NS carried by the operator BP and a navigation system NS incorporated in the vehicle F. The structure of such a navigation system NS will be described below based on the schematic block circuit diagram shown in FIG.

Each navigation system NS has a navigation receiving module NEM. At least one display unit AE is connected to it. The display unit AE is implemented, for example, as a monitor unit or as a display unit, particularly as a "liquid crystal display" display unit. In an advantageous embodiment, the navigation receiving module NEM has a transmitting unit and a receiving unit SEE, and at least one storage medium MM and a processor unit CM. The storage medium MM includes, for example, a data storage medium drive, in particular a DVD drive (not shown in FIG. 2), or can be connected to this type of data storage medium drive. The storage medium MM is provided here specifically to accommodate the map data KD and, in some cases, stationary geographic image data.

The display unit AE is divided into, for example, the first and second display portions AE1 and AE2. Within these display parts, different navigation information is displayed. For example, in the first display portion AE1, a map portion showing the current current location P of the target connected to the navigation system NS is shown. This map portion containing the current location P is created, for example, in the form of a vector graphic based on the assigned map data KD.

Within the second display portion AE2, additional navigation information, such as an actual image recording of the surroundings, created by evaluating constant geographic image data is shown. This is, for example, shown in the second display portion AE2 in addition to the navigation information as a background image. This allows the user of the navigation system NS to use such an actual image recording to get a realistic impression of the surroundings associated with the current location P.

Due to the limited transmission capacity of the communication interface KS known today, the immediate supply of geographic image data GBDs that enable the creation of high resolution real image recordings is not possible. In order to enable the supply of such current geographic image data GBD using the existing wireless communication point KS, an image coding method is advantageously used in the centrally located server unit SU. It is necessary to encode the geographic image data GBD'used and to be transmitted.

For this purpose, the navigation receive module NEM forms a communication connection KV to the server unit SU. The navigation receive module NEM requests the current geographic image data GBD from the server unit SU via the existing communication connection KV. At the same time, for example, the position information PI indicating the current location P of the navigation receiving module NEM is transmitted from the navigation receiving module NEM to the server unit SU via the existing communication connection KV.

The navigation area or geographical area B is divided into individual advantageous square, geographical navigation sections A1 to An by the control unit and the evaluation unit SAR. These navigation compartments advantageously have the same geographical area and are arranged in a chessboard pattern with each other.

Depending on the transmitted position information PI, for example, the navigation category Ap including the current current location P of the target connected to the navigation system NS is obtained.

In an advantageous embodiment, the direction information RI and / or the velocity information GI is additionally transmitted together with the position information PI. The directional information RI indicates the direction of movement of each object connected to the navigation receiving module NEM, for example, the operator BP or the vehicle F, and the velocity information GI indicates the current speed of the object's movement.

Within the central server unit SU, the control routine and evaluation routine SAR executed within the processor unit PU evaluate the transmitted location PI and, in some cases, the transmitted direction RI and / or velocity information GI. The expected area is calculated depending on. The expected region E is advantageously the current location P of the subject connected to the navigation system NS, as well as the geographical location that the subject will probably reach in the next few minutes given the direction and velocity of movement of the subject. Includes area. This forms an advantageous butt-shaped anticipatory region E. In detail, it is formed in the direction of the motion direction of the object indicated by the direction information RI, particularly the vehicle F, starting from the current current location P.

In an advantageous embodiment, the expected region E is defined by a plurality of interconnected navigation categories Ap, Ap-1, Ap + 1, and the like. Here, within the range for obtaining the expected region E, the navigation division Ap including the current current location P, the navigation divisions Ap + 1, Ap-1, etc. adjacent to the navigation division Ap, and the navigation division continuing in the movement direction are advantageous. Ap', Ap + 1', Ap-1', etc. are included. Therefore, a sudden change in direction of vehicle F is also included by the selected expected region E.

The expected region E is extended by the buffer region PB to allow further deviations from the travel route or direction of motion calculated by the navigation system NS. It surrounds the expected region E and is determined depending on the selected expected region E. Advantageously, the buffer region PB is composed of navigation divisions Ap + 2, Ap-2, etc. connected to the expected region E.

In FIG. 3, for example, the expected area E of the geographical area B and the buffer area PB belonging to the expected area E are shown. The object connected to the navigation system NS starts from the current location P and moves in the direction indicated by the direction information RI and the velocity information GI.

The remaining navigation compartments represent another traffic area V that is reachable within geographic area B. This is shown using the geographic image data GBD stored in the central server SU. Therefore, the geographical area B is divided into an expected area E, a buffer area PB, and a traffic area V following it.

If the geographical navigation areas Ap, Ap', Ap + 1, Ap-1, Ap + 2, Ap-2, etc. belonging to the expected area E and the buffer area PB should be determined, they belong by the control routine and the evaluation routine SAR. Geographic image data GBD is selected. In detail, the first geographic image data GBD1 representing the expected region E and the second geographic image data GBD2 representing the buffered region PB are required. The remaining third geographic image data GBD3 is allocated to the traffic area V.

Following this, advantageously, the first and second encoded geographic image data GBD1 and GBD2 are encoded and the resulting first and second encoded geographic image data GBD1', GBD2' are wireless. It is transmitted to the navigation system NS via the communication interface KS. Additionally, the third geographic image data GBD3 is similarly encoded and transmitted to the navigation system NS.

The first, second and third geographic image data GBD1, GBD2, GBD3 significantly reduce the amount of data to be transmitted. To this end, different coding methods are used and / or different coding depths KD1, KD2, KD3 are provided for a unified coding method.

In particular, in order to keep the quality loss caused by coding as small as possible in the individual navigation divisions Ap, Ap', Ap + 1, Ap-1, Ap + 2, Ap-2, etc. in the expected region E, the first The geographic image data GBD1 of is encoded at the first coding depth KD1, and the second geographic image data GBD2 is encoded at the second coding depth KD2. Here, the first coding depth KD1 is selected to be higher than the second coding depth KD2.

The third geographic image data GBD3 assigned to the traffic area V is encoded by the first and second coding depths KD1 and the third coding depth KD3, which is significantly lower than KD2. This ensures that the encoded first geographic image data GBD1'contains even more image information, thereby providing a sufficiently high resolution of the geographic anticipation region E after its encoding. Allows it to be displayed within the navigation system NS. Therefore, the coding depths KD1, KD2, and KD3 decrease as the distance from the current current location P increases from the expected region E to the traffic region V.

The encoded first and second geographic image data GBD1', GBD2' are received by the transmit and receive unit SEE within the navigation receive module NEM, further processed by the control unit CM, and are particularly complexed. In some cases scaled or processed for display in the second display portion AE2 of the display unit AE. In another embodiment, additional vector graphics, road information and / or other navigation information are added to the processed first and second geographic image data GBD1, GBD2. These are superimposed on the real image recording of the expected region or buffer region E, PB created by the first and second geographic image data GBD1 and GBD2.

In addition to the direction information and speed information R1 and G1, the identification number ID individually assigned to the navigation system NS and the predetermined characteristics of the display unit AE of the navigation system, such as the resolution and the number of colors, are inquired. In the range of, it is transmitted from the navigation system NS to the central server unit SU. The identification number ID clearly identifies each navigation system NS by the central server unit SU. That is, the geographic image data GBD already transmitted to the navigation system NS or the navigation receiving module NEM is obtained by using the control routine and the evaluation routine SAR. In order to update this geographic image data, only the transmission of changes that have occurred since the last transmission, the so-called delta update, is required. Thereby, the amount of data to be transmitted can be reduced again by using the incremental coding method.

It is also possible to obtain the coded geographic image data GBD1', GBD2', GBD3' for different mileages or routes. It is first stored in the storage unit MU of the central server unit SU and called by the navigation system NS when needed. This makes it possible to dynamically create alternative routes.

The method described above can also be used as an extension to the navigation system NS with stationary geographic image data. This stationary geographic image data is provided, for example, on a local storage medium or a data storage medium of the navigation system NS. For this purpose, for example, when leaving the geographical area stored on the storage medium, the above-mentioned communication connection KV to the server unit SU is formed. Through this server unit, the required additional geographic image data GBD is similarly called in an encoded form, and in some cases costly, to give the user of the navigation system NS an expanded virtual coverage area. Provided.

The encoded geographic image data GBD1'~ GBD3' transmitted from the central control unit SU can also be personalized, especially for fleet management applications. For this purpose, for example, the central control unit SU is configured as a fleet management server unit. It additionally transmits traffic and / or weather information to the assigned navigation system NS to the encoded geographic image data GBD1'~ GBD3'.

In the above, the present invention has been described according to examples. It should be understood that many changes and variations are possible without departing from the basic idea of the present invention.