WO2005038742A1 - Method and device for generating traffic information - Google Patents

Abstract

Traffic situation (b) of an objective road is sampled at specified intervals along the road, a sequence of sampled data thus abtained is divided into a plurality of blocks (block 1, block 2, block 3), and the sampled data included in the blocks is encoded by orthogonal transformation on a block basis. Since the encoded data is decoded on a block basis, program load of encoding and decoding is lessened and a work memory having a small memory quantity can be used in the processing.

Description

 Specification

 Method and apparatus for generating paternity information

 Technical field

 The present invention relates to a method for generating traffic information, a device for generating traffic information by the method, and a device for reproducing the traffic information, and is heavy in encoding processing during generation and decoding processing during reproduction. It realizes traffic information without burden.

 Background art

 [0002] Currently, VICS (Road Traffic Information and Communication System), which provides a service for providing road traffic information to car navigation devices, etc., receives road traffic information from vehicle sensors and image sensors installed on roads. Collects, edits, and provides traffic congestion information, such as traffic congestion information and travel time information indicating the required time, through FM multiplex broadcasting and beacons.

[0003] In the current VICS information, current traffic information is expressed as follows.

 Traffic congestion conditions include traffic congestion (general road: ≤10km / h 'highway ^ 20km / h), congestion (general road: 10-20km / h' highway: 20-40km / h), and quiet (general road) : ≥ 20km / h 'Highway: ≥ 40kmZh). The information is displayed in three stages. If information cannot be collected due to a failure of the vehicle detector, "Unknown" is displayed.

[0004] The traffic congestion information indicating the traffic congestion status is obtained when the entire VICS link (a road position information identifier used in VICS) has the same congestion status.

 "VIC S link number + condition (traffic congestion Z congestion Z desertion Z unknown)"

 Is displayed, and only part of the link is congested,

 "VICS link number + start distance of congestion (distance from start of link) + end distance of congestion (distance from start of link) + state (congestion)"

 Is displayed. In this case, when the traffic starts from the beginning of the S-link, the head distance SOxff is displayed. If different congestion states coexist in a link, each congestion state is described in this way.

[0005] Also, link travel time information indicating the travel time of each link is: "VICS link number + travel time"

 Is displayed.

 [0006] The car navigation device that uses this traffic information has a digital map database in which VICS link numbers are defined in the road network, and specifies the target road for traffic information from the VICS link numbers included in the VICS information. I do.

 [0007] However, the link numbers defined in the road network need to be replaced with new numbers according to new road construction or changes, and the digital map data produced by each company must be updated accordingly. Therefore, the method of specifying the road position using the link number requires a large social cost for maintenance.

 [0008] In order to improve such a point, Japanese Patent Application Laid-Open No. 2001-41757 proposes a method of notifying a road position on a digital map without using a common link number. In this method, the transmitting side sets a plurality of nodes pl, ρ2, and 'ρΝ between road sections to be transmitted on the digital map of the transmitting side, as shown in Fig. 32 (a). As shown in b), "road shape data" in which the position data of the plurality of nodes pl, ρ2, and 'ρΝ are arranged is generated. For example, when notifying the location of an accident that has occurred in this road section, the road shape data and the distance from the reference node (for example, pi) to the accident location are transmitted to the receiving side. The receiving side identifies the road section by performing position identification (including the concept of map matching) that associates each node position included in the road shape data on its own digital map, and based on the information on the distance from the reference node. To identify the accident location.

 [0009] Also, Japanese Patent Application Laid-Open No. 2003-23357 discloses a method of reducing the data amount by performing variable length coding on the road shape data.

As shown in Fig. 33, the currently provided VICS traffic information is a graph with the number of states that can express traffic information (traffic expression resolution) on the vertical axis and the position (or section) resolution on the horizontal axis. Expressed above, traffic congestion information can be displayed in 10-m units with respect to its position.However, the number of traffic information expression states is only three states: traffic congestion, congestion, and low traffic. It is positioned as information with low traffic expression resolution. In addition, the link travel time can be expressed in units of 10 seconds. Force Position resolution is only in units of links, and it is not possible to express even the fine velocity distribution in the link. That is, The link travel time information is positioned as information with high traffic expression resolution but low positional resolution.

 [0010] As described above, the current traffic information has extreme resolution of the information expression, and the intermediate resolution within the circle shown in FIG. 33 cannot be expressed.

 It is possible to collect traffic information in the circle itself, and collect and use existing sensors. The original information before editing may vary to some degree depending on sensor density, etc. It is traffic information of Le. In addition, a road traffic information collection system (probe information collection system), which has been researched in recent years, collects travel trajectory information and measurement information such as speed from running vehicles (probe cars) to help generate traffic information. In a system or a floating car data (FCD) collection system, information at each level within this circle can be collected at the center, depending on the purpose of information collection and the amount of data to be transmitted.

 [0011] The present inventors have previously proposed a method of setting the position resolution and the expression resolution of traffic information to be transmitted at arbitrary locations in Fig. 33.

 In this method, traffic conditions represented by vehicle speed, travel time, congestion degree, and the like are regarded as a function that changes along the road, and this function is sampled along the road at intervals corresponding to the position resolution. In addition, the obtained sampling data is rounded according to the expression resolution. Fig. 34 shows the array (b) of discrete values (sampled data) and the target road (a) thus obtained. The length of one cell in Fig. 34 (b) indicates the interval between sampling points where traffic conditions were sampled.

 [0012] The data sequence of the sampled data is encoded by orthogonal transformation, and the encoded data and the road shape data indicating the target road section are transmitted to the receiving side. The receiving side identifies the road section using the road shape data, decodes the encoded data, and reproduces the sampled data representing the traffic situation in that section.

 [0013] Using this method, for example, traffic information on a road section of several kilometers can be encoded and the information amount can be reduced to provide information. The measured speed information can be transmitted to the center with a small amount of data.

[0014] In this case, as the target road section of the traffic information is set longer, a large amount of data can be collectively encoded and compressed, so that the data compression ratio is improved. The present invention improves this traffic information generation method.

 [0015] Indeed, when generating traffic information by this method, the longer the distance of the target road section, the higher the data compression ratio. However, if the distance of the target road section is long, the following problems will occur.

 [0016] (1) At the time of encoding / decoding traffic information, since the number of samplers (data amount) that must be dealt with collectively is large, it is difficult to implement a program that places a heavy burden on the program. In addition, it is necessary to increase the memory size of the work memory used for the encoding / decoding processing, and it is difficult to realize this in a PDA or a low-cost car navigation device. In addition, it is difficult to perform encoding and decoding processes on standardized chips.

 [0017] (2) If the distance of the target road section is long, there is a high possibility that the target road section includes a congestion section that requires detailed traffic information and a quiet section that does not require detailed information. It is difficult to change the level of detail (compression ratio) within a section, so it is difficult to provide detailed information as needed.

 [0018] (3) If the distance of the target road section is long, for example, the distance from the base point reported by the transmitting side may be largely deviated on the receiving side, and a deviation in the distance direction of the road cannot be ignored.

 The present invention solves these problems, and a method of generating traffic information that can easily change the compression ratio with a light load on the encoding and decoding processes and that can correct a displacement in the distance direction. It is an object of the present invention to provide a device for generating traffic information by the method and a device for reproducing the traffic information.

 Patent document 1: JP 2001-41757 A

 Patent Document 2: Japanese Patent Application Laid-Open No. 2003-23357

 Disclosure of the invention

 [0019] The traffic information generation method of the present invention is a traffic information generation method for sampling traffic conditions of a target road at predetermined intervals along a road, wherein the array of sampled data is divided into a plurality of blocks. The sampled data included in this block is subjected to orthogonal transform coding in block units.

[0020] Since the decoding of the encoded data is also performed in units of blocks, the load on the program for encoding and decoding is reduced, and the amount of work memory used for this processing is small. I'm done.

 In the traffic information generating method of the present invention, the number of sampling data included in each of the blocks is set to be equal to or less than a predetermined upper limit.

If there is no limit on the number of sampled data included in the code data, the traffic information receiving side needs to adopt a processing system that can cope with a large number of sampled data. If the upper limit is set for the number of data, the receiving side can easily deal with it.

Further, in the traffic information generation method of the present invention, the number of sampled data included in each block is set to be constant.

 This makes it possible to standardize the decoding mechanism of the traffic information receiving device.

In the traffic information generation method of the present invention, the target road is divided at regular intervals, and blocks are generated corresponding to the divided sections.

 This makes it possible to standardize the process of encoding and decoding traffic information.

In the traffic information generation method of the present invention, the target road is divided at unequal distance intervals with the selected point as a boundary, and blocks are generated corresponding to the divided sections.

 In addition, an intersection or a facility point is selected as the boundary.

[0025] According to this method, a section in which a change in traffic flow occurs steadily can be included in one block, and traffic information can be displayed more easily.

 Further, in the traffic information generating method of the present invention, a block is generated by dividing the sampled data into units of time.

When the sampled data is measurement information measured by the in-vehicle probe car, the measurement information is divided into a plurality of pieces according to the time zone of the measurement time, and a block is generated based on the divided measurement information. I have.

As described above, the block may be divided into time units.

Further, in the traffic information generation method of the present invention, when the sampled data is measurement information measured by the probe car on-board unit, the traveling information on the probe car on-board unit and the position of the probe car on-board unit are associated with each other. Based on at least one of the location information on the map information and the communication operation information in the communication unit mounted on the vehicle-mounted device. Then, a block marker indicating the boundary of the block is set.

 [0028] Thereby, for example, a block marker can be set at a change point of a traffic condition according to a traveling state of a vehicle mounted on a probe car, and a block can be divided, so that a change point of traffic information can be easily distinguished. It becomes.

 [0029] Further, in the traffic information generation method of the present invention, when a predetermined event occurs in traveling of the vehicle-mounted probe car based on at least one of the traveling information, the position information, and the communication operation information. Is set to the block marker.

 [0030] With this, by setting a block marker when a predetermined event occurs, for example, turning right or left at an intersection or entering a facility, it is possible to easily distinguish a change point in traffic information, and Blocks can be divided and set according to the section where the situation changes. Further, even when the measurement information is leveled by performing the code for each block, it is possible to easily determine the change point of the traffic information.

 In the traffic information generating method of the present invention, the data compression ratio in encoding is set in units of blocks.

 Therefore, traffic information can be encoded with necessary details according to traffic conditions.

[0032] The data compression ratio changes according to the average speed of the block represented by the sampled data.

 Alternatively, the average speed of the block represented by the sampled data is changed according to the rate of change between the blocks.

 Alternatively, the change is made according to an event occurring in a section corresponding to the block.

 Alternatively, in a block including the measurement information of the probe car on-board unit as the sampling data, the change is performed by an event such as a sudden brake measured by the probe car on-board unit.

Alternatively, it is changed according to the measurement time of the measurement information measured by the probe car on-board unit.

 Alternatively, it changes depending on whether or not the measurement point of the measurement information measured by the probe car vehicle-mounted device is around the specified position.

Further, in the traffic information generation method of the present invention, when performing coding on a block basis, the range of the block is extended, and encoding is performed on the sampled data of the block including the sampled data of the extended part. . [0036] By doing so, it is possible to reduce the mismatch (block noise) generated at the boundary between blocks when decoding.

 To reduce block noise, the value of the sampled data in the extended part is made to match the value of the sampled data at the original boundary of the block.

Alternatively, the value of the sampled data of the extended portion is made to match the value of the corresponding sampled data of the block adjacent to the block.

 Alternatively, the value of the sampled data of the extension is matched with the value of the corresponding sampled data of the block adjacent to the block, and the sampled data of the block including the extension is multiplied by the window function. The value is used as the block sampling data.

[0038] In the traffic information generation method of the present invention, position information indicating a boundary of a block is added to road reference data for specifying a target road to be a part of the traffic information.

 The receiving side of the traffic information can correct the distance displacement of the target road in the distance direction using the position information indicating the boundary of this block, and can accurately reproduce the traffic information on its own digital map. it can.

 [0039] The traffic information reproducing method of the present invention is a method of reproducing traffic information in which traffic conditions of a target road are sampled at predetermined intervals along a road. The traffic information reproducing method divides an array of sampled data into a plurality of blocks. The traffic information generated by performing coding in units of the blocks is obtained, and the traffic information is decoded in units of blocks to reproduce sampled data.

 [0040] Thus, by decoding traffic information in block units, the load on the program is reduced, and the memory capacity of the work memory used for this processing can be reduced.

 In the traffic information reproducing method of the present invention, in reproducing the sampled data, the traffic information is output in association with the position information.

 Alternatively, at the time of reproducing the sampled data, the traffic information is displayed on the display unit in association with the position information.

 As a result, the processing load can be reduced when traffic information is decoded in units of blocks and output and display are reproduced and used.

[0042] The present invention also provides a program for causing a computer to execute each procedure of the traffic information generation method described in any of the above. Further, the present invention provides a program for causing a computer to execute each step of the traffic information reproducing method described in any of the above.

 [0043] The traffic information generating device of the present invention is a traffic information generating device that samples traffic conditions of a target road at predetermined intervals along a road, and includes a plurality of arrays of sampled data corresponding to the traffic conditions. A block dividing unit that divides the sampled data into blocks, and an encoding unit that performs code conversion by orthogonal transform on the sampled data included in the block in units of the block.

 [0044] Thus, by encoding traffic information in units of blocks, the load on the program can be reduced, and the memory capacity of the work memory used for this processing can be reduced.

 Also, in the present invention, the traffic information generation device includes a traffic information blocking unit that divides an array of sampled data obtained by sampling the traffic condition of the target road into a plurality of blocks, and a code of the sampled data included in the block. Block-ratio determination unit that determines the compression ratio in image coding, a block-noise reduction processor that performs processing to reduce block noise that occurs at block boundaries during decoding, and block-noise reduction processing. And an orthogonal transform code processing unit that performs encoding by orthogonal transform on a block-by-block basis with respect to the sampled data of the block.

 [0045] In this device, traffic information can be encoded in small block units, and the compression rate in encoding can be set in small block units.

 Further, the traffic information generating apparatus of the present invention further includes a block position marker follow-up unit for adding position information of a block marker indicating a block boundary to road reference data for specifying a target road, and performing orthogonal transform coding processing. The encoded data generated by the section and the road reference data to which the position information of the block marker is added are provided.

[0046] The receiving side can specify the target road and the break of the block from the road reference data.

 Further, in the traffic information generation device according to the present invention, the block position marker adding unit divides the target road at a predetermined distance interval, and sets a block marker corresponding to the divided section.

As described above, for example, a block is divided into a predetermined distance section such as a fixed distance section, and the block is divided into blocks. The traffic information can be encoded every time.

 Further, in the traffic information generation device of the present invention, when the sampled data is measurement information measured by a probe car on-board unit, the block position marker adding unit divides the measurement information at a predetermined time interval, and The block marker is set according to the measured information.

 As described above, for example, blocks can be divided at predetermined time intervals such as fixed time intervals, and traffic information can be encoded for each block.

 Further, in the traffic information generation device of the present invention, when the sampled data is measurement information measured by a probe car on-board unit, the block position marker adding unit may include: Based on at least the location information on the map information associated with the location of the on-vehicle device and the communication operation information in the communication unit mounted on the probe car on-vehicle device, based on the deviation, the block marker is identified. Set it as you like.

 [0049] This makes it possible to divide a block by setting a block marker at, for example, a point of change in traffic conditions according to the traveling state of the on-board probe car, and perform coding for each block to obtain measurement information. Even when averaged, the change point of the traffic information can be easily distinguished.

 [0050] The traffic information reproducing device of the present invention is a traffic information reproducing device in which the traffic condition of a target road is sampled at predetermined intervals along the road, wherein a plurality of arrays of sampled data corresponding to the traffic condition are provided. An acquisition unit that acquires traffic information generated by performing encoding on a block basis by dividing the traffic information into blocks, and a reproduction unit that decodes the traffic information on a block basis and reproduces sampled data. Unit.

 [0051] Thus, by decoding the traffic information in block units, the load on the program is reduced, and the memory capacity of the work memory used for this processing can be reduced.

Also, in the present invention, the traffic information reproducing apparatus divides the sampled data indicating the traffic condition of the target road into blocks and encodes the traffic information, and the road reference data indicating the boundary positions of the target road and the blocks. A receiving unit that receives, a traffic information decoding unit that decodes traffic information in block units and reproduces sampled data, and removes the sampled data added to reduce block noise from the reproduced sampled data The mark included in the range of each block For each block that calculates a correction coefficient for a deviation occurring in the distance direction of the target road, using the block noise reduction processing unit that acquires the main data and the information on the boundary position of the block included in the road reference data. A correction coefficient calculation unit and a block-by-block unit distance correction unit for specifying an accurate position of the block on the target road using the correction coefficient and positioning the sampled data at the sampling position of the block are provided. I have.

 In this traffic information reproducing apparatus, since the traffic information is decoded in units of small blocks, the load on the program is reduced and the memory capacity of the work memory can be reduced. In addition, using the information on the boundary positions of blocks on the digital map held by the user, the block positions can be accurately specified, and the sampled data can be accurately positioned at the sampling positions within the block.

 In the traffic information generation method of the present invention, the traffic information of the target road is divided into small blocks and coded, so that the load memory used in the encoding / decoding processing that reduces the load on the program is small. However, a small memory size is sufficient. Therefore, it is possible to leave the encoding / decoding process to the semiconductor chip.

 Further, since the compression ratio of the traffic information can be changed in small block units, the detail of the traffic information can be set as needed.

 In addition, it is possible to correct a deviation in the distance direction of a road by using a boundary position of a traffic information block, and to convey highly accurate traffic information.

 Brief Description of Drawings

 FIG. 1 is a schematic diagram illustrating a method for generating traffic information according to a first embodiment of the present invention.

 FIG. 2 is a block diagram showing a configuration of an information transmitting device and an information utilizing device according to the first embodiment of the present invention.

 FIG. 3 is a view showing a traveling locus with probe force and measurement data and block force information in an embodiment of the present invention.

 FIG. 4 is a flowchart showing a procedure for adding a block marker to probe car measurement information according to the first embodiment of the present invention.

[FIG. 5] Road shape data 'traffic information and block marker information according to an embodiment of the present invention. FIG.

 FIG. 6 is a flowchart showing a procedure for applying a block power to road shape data'traffic information according to the first embodiment of the present invention.

 [FIG. 7] FIG. 7 (a) shows a DWT filter circuit, and FIG. 7 (b) shows an IDWT filter circuit.

[FIG. 8] FIG. 8 (a) shows a lifting configuration of a DWT filter circuit, and FIG. 8 (b) shows a lifting configuration of an IDWT filter circuit.

 FIG. 9 is a flowchart showing a procedure of an orthogonal transform encoding process in the embodiment of the present invention.

FIG. 10 is a diagram showing a change in data due to DWT.

FIG. 11 is a diagram illustrating a transmission data portion.

 FIG. 12 is a diagram showing parameter information and traffic information generated by the method according to the embodiment of the present invention.

 FIG. 13 is a diagram for explaining a boundary value extending method used in the block noise reduction method according to the embodiment of the present invention.

 FIG. 14 is a flowchart showing a procedure of a boundary value stretching method in the embodiment of the present invention.

 FIG. 15 is a diagram showing parameter information generated by a boundary value bow [stretching method] in the embodiment of the present invention.

 FIG. 16 is a diagram illustrating an out-of-bounds coding method used in the block noise reduction method according to the embodiment of the present invention.

 FIG. 17 is a flowchart showing a procedure of an out-of-bounds encoding method in the embodiment of the present invention.

FIG. 18 is a diagram illustrating a method of using a window function in the block noise reduction method according to the embodiment of the present invention.

 FIG. 19 is a flowchart showing a procedure of a window function using method according to the embodiment of the present invention.

FIG. 20 is a diagram showing parameter information generated by a window function using method according to the embodiment of the present invention.

FIG. 21 is road shape data generated by the traffic information generation method according to the embodiment of the present invention. It is a figure showing the data composition of power information and traffic information.

FIG. 22 is a diagram illustrating another block marker setting method in the traffic information generation method according to the embodiment of the present invention.

Garden 23] is a diagram showing the relationship between the length of the resampler and the number of bits required to display the distance between node 'block markers.

FIG. 24 is a diagram showing another data structure of road shape data generated by the traffic information generating method according to the embodiment of the present invention.

 FIG. 25 is a flowchart showing a processing procedure of IDWT.

FIG. 26 is a diagram illustrating a distance shift correction method according to an embodiment of the present invention.

FIG. 27 is a schematic diagram showing a modification of the traffic information generation method according to the embodiment of the present invention.

 FIG. 28 is a schematic diagram illustrating a first example and a second example of a traffic information generation method according to the second embodiment of the present invention.

 FIG. 29 is a schematic diagram illustrating a third example and a fourth example of the traffic information generation method according to the second embodiment of the present invention.

FIG. 30 is a block diagram showing a configuration of an information transmitting device and an information utilizing device according to a second embodiment of the present invention.

FIG. 31 is a flowchart showing a procedure for assigning a block marker to probe car measurement information according to the second embodiment of the present invention.

FIG. 32 is a diagram illustrating road shape data.

 FIG. 33 is a diagram for explaining the position resolution and expression resolution of traffic information.

[34] FIG. 34 is a diagram for explaining a function of a road and a method of expressing traffic information as viewed.

BEST MODE FOR CARRYING OUT THE INVENTION

 (First Embodiment)

In the traffic information generation method according to the embodiment of the present invention, as shown in FIG. 34 (b), traffic information positioned at equal intervals along the target road is divided into blocks of a fixed distance (that is, a fixed number of sampling points). And the traffic information is encoded in units of the small blocks. Then, on the receiving side, the road shape data of the target road that clearly indicates the divided section of traffic information, and / J The traffic information encoded by the order is transmitted. The receiving side individually decodes the traffic information of the small blocks, and connects the obtained traffic information to reproduce the traffic information of the target road.

In this case, the number of sample points (data amount) included in the small block is the number of sample points (data amount) handled at the time of encoding and decoding traffic information, and thus the load on the program is reduced. In addition, the work memory used for encoding and decoding of traffic information needs only a small memory size.

FIG. 1 schematically shows a method of generating this traffic information.

 Fig. 1 (a) shows the target road for traffic information, and Fig. 1 (b) shows the traveling speed measured by the probe car per unit time, the vertical axis is the speed, and the horizontal axis is the distance from the base point of the target road. This is represented by the graph that was taken. This graph is nothing more than a graph of traffic information represented in the form of Fig. 34 (b), even though there are differences in sampling point intervals. This speed information may be regarded as traffic information sent from the probe force to the center, or as traffic information collected from the probe car by the center and provided to the car navigation device or the like.

[0059] In the graph of Fig. 1 (b), a solid line represents speed measurement data, a dashed line represents speed information obtained by compressing the measurement data at a low compression ratio, and a fine dotted line represents the measurement data. The speed information compressed at a moderate compression rate is shown, and the coarse dotted line shows the speed information compressed at a high compression rate for the measured data.

[0060] The traffic information is divided here in units of 1000m. A block marker indicating the boundary position of the traffic information block is set on the target road, and road shape data of the target road is generated so that the position of the block marker can be known (“setting of block marker”). In Fig. 1 (a), nodes for obtaining this road shape data are set at intervals of distance L1 in sections where the target road has a large curvature and where the curve is tight, and in nodes where the curvature is small and the curve is gentle, Distances are set at intervals of L2 (> L1), and block marker positions are added to nodes. Instead of changing the position of the block marker to a node, the identification information of the node adjacent to the block marker and the information of the distance to the node may be held.

[0061] The traffic information divided into blocks is encoded by orthogonal transform in units of blocks ("orthogonal transform encoding process"). At this time, the compression ratio of the encoded data is set in block units.

'Each compression ratio setting'). [0062] Also, when traffic information encoded in units of blocks is decoded and connected to information of each block, inconsistency (block noise) may occur at block boundaries. In order to avoid this, perform processing to reduce block noise in advance (“Block noise reduction processing”).

 [0063] The traffic information encoded in block units is provided together with the road shape data of the target road.

 The receiving side that receives these information specifies the target road from the road shape data, and positions the traffic information decoded in block units on the target road. At this time, the positional deviation in the length direction of the target road is corrected using the distance information between the block markers (“distance deviation correction processing”).

 FIG. 2 is a block diagram showing a configuration of an information transmitting device 10 that provides traffic information generated by this method and an information utilizing device 40 that utilizes the provided traffic information. The information transmitting device 10 is a probe car in-vehicle device that transmits probe information or a traffic information center that provides edited traffic information. The information utilization device 40 is a probe information collection center that collects probe information, or a power navigation device that receives provision of traffic information.

[0065] The information transmitting device 10 is a traffic information / measurement information input unit 11 that receives measurement information and traffic information positioned at equal intervals along a road, and a traffic that generates traffic information in block units from the input information. An information blocking unit 14, a block-by-block compression ratio determining unit 16 for setting a compression ratio for each traffic information block, a block noise reduction processing unit 17 for performing block noise reduction processing, and an orthogonal transform code for traffic information in block units. Transform processing unit 19 that performs the conversion process, a digital map database (A) 12, and a shape data extraction unit that generates, from the input information, the travel trajectory of the probe car and the road shape data of the target road for traffic information 13, a block position marker adding unit 15 for adding a block marker to the road shape data, a variable length coding processing unit 18 for performing variable length coding on the road shape data, and a block. The system includes a data transmission unit 20 for transmitting traffic information and road shape data encoded in units, and a data storage unit 21 for storing the traffic information and road shape data and providing the data through an external medium. On the other hand, the information utilization device 40 includes a data receiving unit 41 that receives data transmitted from the information transmitting device 10, and a shape-encoded data decoding unit that decodes variable-length encoded road shape data. 42, a shape data restoration unit 43 for restoring road shape data, a digital map database ( _{B) 45} , and roads represented by the road shape data on a digital map in the digital map database ( _{B) 45.} A position specifying unit 44 for specifying the position, a block position specifying unit 46 for specifying the position of the block marker, a block-by-block correction coefficient calculating unit 47 for calculating a correction coefficient used for the correction processing of the distance shift, and an orthogonal transform coding A traffic information coded data decoding unit 48 for decoding traffic information in units of blocks, and performs a block noise reduction process on the decoded traffic information.

 Block noise reduction processing unit 49, block-by-block unit distance correction unit 50 that corrects the position of sampling points in blocks, traffic information superimposition unit 51 that superimposes traffic information on target roads, and information that uses traffic information Utilization unit 52 is provided.

[0067] The information transmitting device 10 constitutes an encoder from the viewpoint of generating encoded data, and the information utilizing device 40 constitutes a decoder from the viewpoint of restoring encoded data.

 A method of generating traffic information performed by the information transmitting apparatus 10 will be described in detail.

[0068] <Setting of block marker>

 When the information transmitting device 10 is a vehicle-mounted probe car, the traffic information is measured at the coordinates of the sampling points (nodes) and the sampling points from the measurement information input unit 11 as shown in FIG. 3 (a). Measurement information such as a measurement time, a distance between sampling points and a speed is input. The traffic information blocking unit 14 generates block-based traffic information from the input information, and the shape data extracting unit 13 selects the coordinates of the sampling point for the input information force and selects the road shape data of the traveling locus. Then, the block position marker tracking unit 15 adds the information of the block marker to the road shape data.

The setting process of the block marker is performed according to the procedure shown in FIG.

A fixed distance (or a fixed number of standardized points) is set in advance as a unit for assigning a block marker. Alternatively, this distance may be dynamically determined according to the amount of free memory that can be used as a work memory for the code. The measurement is repeated every unit time (or at fixed distance intervals) until the time when the probe information is transmitted to the probe information collection center, and the measurement data is accumulated in the buffer (step 1). When the probe information transmission time comes (step 2), the traffic information blocking unit 14 determines the unit of block marker assignment (step 3), and the measurement information input from the traffic information / measurement information input unit 11 Then, a block marker is set in the unit of assignment, and block marker information shown in FIG. 3 (b) is generated (step 4).

 [0071] When a fixed distance (or the number of sampling points) is determined in advance as the block marker assignment unit, the accumulated value of the inter-node distance data of the input measurement information or the number of sampling points) is used as the block marker. Each time the distance reaches the assigned unit (the number of sampling points), the node number is written to the block marker information. When dynamically determining the distance of the block marker addition unit according to the free memory amount, measure the current free memory amount and determine the distance (or the number of sampling points) of the block marker addition unit from the value.

 The traffic information blocking unit 14 also extracts measurement data such as a measurement time and a distance and a speed between sampling points from the measurement information in which the block markers are set, and generates measurement information in block units ( Step 5). The traffic information blocking unit 14 sends the generated block marker information to the block position marker adding unit 15, and the block position marker adding unit 15 generates the traveling locus generated by the shape data extracting unit 13 based on the blocker force information. The position information of the block marker is added to the road shape data (step 6).

 When the information transmitting device 10 is a center that provides traffic information, the traffic information 'measurement information input unit 11 outputs traffic information of a number of roads as shown in FIG. 5 (a). The coordinates of the sampling points (nodes), the distance between the sampling points, and the traffic information positioned at the sampling points are input.

 [0074] The traffic information blocking unit 14 generates traffic information in block units from the input information, and the shape data extraction unit 13 selects the coordinates of the sampling point for the input information force and selects the coordinates of the target road of the traffic information. The road shape data is generated, and the block position marker adding unit 15 adds the information of the block marker to the road shape data.

The process of setting the block marker is performed according to the procedure shown in FIG. Set a fixed distance (or a fixed number of sampling points) in advance as the unit to which the block marker is assigned . Alternatively, in an interactive system, this distance may be dynamically determined according to the request of the partner device.

 When the shape data and traffic information (FIG. 5 (a)) are inputted in order from the identification number 1 through the traffic information'measurement information input unit 11 (Step 10, Step 11), the traffic information blocking unit In step 14, a block marker assignment unit is determined (step 12), a block marker is set for the input information in the assignment unit, and block marker information shown in FIG. 5 (b) is generated (step 13). ).

 [0077] When a fixed distance (or the number of sampling points) is determined in advance as a unit for assigning a block marker, the accumulated value of the distance data between nodes of the input measurement information or the number of sampling points) is used as the block marker. Each time the distance reaches the assigned unit (the number of sampling points), the node number is written to the block marker information. In the case of an interactive system, a block marker is set for each distance or the number of sampling points for which the opponent's device power is also applied.

 [0078] The traffic information blocking unit 14 also extracts each piece of traffic information positioned at the sampling point in units of blocks from the input information in which the block markers are set, and generates traffic information in units of blocks (step 14). The traffic information blocking unit 14 sends the generated block marker information to the block position marker adding unit 15, and the block position marker adding unit 15 generates the traffic information generated by the shape data extracting unit 13 based on the blockability information. The position information of the block marker is added to the road shape data of the target road (step 15).

 [0079] Such processing is repeated until the setting of the block marker is completed for all the shape data.

 (Step 16, Step 17). The traffic information blocking unit 14 constitutes a block dividing unit (traffic information blocking unit) that divides an array of standardized data corresponding to traffic conditions into a plurality of blocks.

 [0080] <Compression ratio setting for each block>

 The block-by-block compression ratio determining unit 16 sets the compression ratio of the traffic information block generated by the traffic information blocking unit 14 as follows.

(1) When the information transmitting apparatus 10 is a traffic information providing center or an on-board probe car, when the speed change between blocks is large, detailed information is required, so the compression ratio is set to a small value. . Specifically, the average speed of each block is calculated, and the average speed of each block is calculated. The compression ratio is changed according to the difference in the average speed.

 (2) If the information transmitting apparatus 10 is a traffic information providing center, and if there is an event such as an accident “construction” regulation, detailed information is required, so the compression ratio is set to a small value. Specifically, it determines whether there is an event such as an accident, construction, or regulation in each block, and changes the compression ratio according to the degree of impact of the event on traffic flow (number of restricted lanes, etc.).

 (3) When the information transmitting device 10 is a vehicle-mounted probe car, the compression ratio is changed depending on whether or not a measurement event has occurred, such as reducing the compression ratio when a sudden brake is applied. Specifically, it is determined whether or not an event designated in advance has occurred in each block, and the compression ratio is changed according to the content of the event.

 (4) When the information transmitting apparatus 10 is an in-vehicle probe car device, the longer the time elapsed from the time of measurement, the lower the information freshness of the measured information. Specifically, the time at the last (or first) measurement point of each block is calculated, and the compression ratio is changed according to the elapsed time.

 (5) When the information transmitting device 10 is a probe car in-vehicle device, the compression ratio around the position designated by the information collecting center is changed. Specifically, it is determined whether or not a location specified by the information collection center exists in each block, and if so, the compression ratio of the block is changed to the specified compression ratio.

 [0086] <Orthogonal transform coding process>

 Next, an orthogonal transform coding process performed by the orthogonal transform coding processing unit 19 before the block noise reduction process will be described.

 Here, a case where a discrete wavelet (Wavelet) transform (DWT) is used as the orthogonal transform will be described.

 This DWT can be realized by a filter circuit that recursively divides the low frequency band, and the inverse transform (IDWT) can be realized by a filter circuit that repeats the synthesis reverse to the division. Although various filter configurations can exist in DWT, the following describes an example using a 2 × 2 filter of DWT (a filter that generates one wavelet coefficient and one scaling coefficient from two inputs). explain.

FIG. 7A shows a DWT filter circuit. This DWT circuit is a low-pass filter 181, a high-pass filter 182, and a cascade connection of a plurality of circuits 191, 192, 193 provided with a thinning circuit 183 for thinning out the signal by half. The high-frequency component of the signal input to the circuit 191 passes through the high-pass filter 182, is then decimated to 1Z2 by the decimation circuit 183, and is output.The low-frequency component is passed through the low-pass filter 181. , Is decimated to 1Z2 by the decimating circuit 183 and input to the next circuit 192. FIG. 8A shows a specific configuration of each of the circuits 191, 192, and 193. “Round” in the figure represents a rounding process.

When two pieces of data are input to the circuit 191, one piece of data of a high-frequency component (this is referred to as an ゥ -wavelet coefficient) and one piece of data of a low-frequency component (this is referred to as a scaling coefficient) Is converted to The scaling coefficient indicates information obtained by smoothing (averaging) the input data, and the wavelet coefficient indicates difference information for restoring the original data from the scaling coefficient.

[0090] Further, when the circuit 191 2 ^two data inputs, two wavelet coefficients and the two scale one ring coefficients is generated, the two scaling factors force S, the input to the circuit 192, Similarly, one wavelet coefficient and one scaling coefficient are generated. The wavelet coefficients and the scaling coefficients generated by the circuit 191 are called primary wavelet coefficients and primary scaling coefficients, respectively.The wavelet coefficients and the scaling coefficients generated by the circuit 192 are called secondary wavelet coefficients and This is called the secondary scaling factor.

[0091] Similarly, when the 2 ^three data are input to the circuit 191, it is generated and four primary wavelet coefficients and four primary scaling coefficients, this four primary scaling coefficients force circuit 19 2 , Two second-order wavelet coefficients and two second-order scaling coefficients are generated, and when these two second-order scaling coefficients are input to the circuit 193, one third-order scaling coefficient and one And third-order wavelet coefficients are generated.

 As described above, in the 2 × 2 filter, the number of input data needs to be a multiple of 2 to the Nth power.

FIG. 7 (b) shows an IDWT filter circuit. The IDWT circuit includes an interpolation circuit 186 for interpolating the signal twice, a low-pass filter 184, a high-pass filter 185, and an adder for calculating the outputs of the low-pass filter 184 and the high-pass filter 185. 187 and a plurality of circuits 194, 195, and 196 with a cascade connection. The low-frequency component and high-frequency component signals are interpolated twice, added, and input to the next circuit 195. FIG. 8B shows a specific configuration of each of the circuits 194, 195, and 196.

[0093] Now, in circuit 194, one cubic scaling coefficient generated by the filter circuit of Fig. 7 (a) is input as a low-frequency component, and one tertiary wavelet coefficient is input as a high-frequency component. The circuit 194 reproduces two secondary scaling factors. Also, by inputting one of the secondary scaling coefficients as a low-frequency component of the circuit 195 and one secondary wavelet coefficient as a high-frequency component, two primary scaling coefficients are reproduced. You. Therefore, four primary scaling coefficients can be reproduced by combining two secondary scaling coefficients and two wavelet coefficients. Similarly, in the circuit 196, and four primary scaling coefficients reproduced in the circuit 195, four primary wavelet coefficients and by Ri 2 ^three input data to the combining can be reproduced.

 [0094] In other words, one tertiary scaling coefficient, one tertiary wavelet coefficient, two tertiary wavelet coefficients, and four tertiary wavelet coefficients converted from eight input data by the filter circuit of FIG. Using the primary wavelet coefficients of, eight input data can be reproduced.

 [0095] It should be noted here that the four primary scaling coefficients can be reproduced without the four primary wavelet coefficients, and the state of the eight input data can be changed by the scaling coefficients. The point is that it can be known with a coarse resolution. In addition, two secondary scaling coefficients can be reproduced only from one tertiary scaling coefficient and one tertiary wavelet coefficient. You can find out at

 [0096] In Fig. 1 (b), the graph shown as high compression shows the transition of the speed using the low-order scaling coefficient obtained by the DWT conversion of the speed data, Graphs displayed as reduced compression use medium-order scaling factors, and graphs displayed as low compression use higher-order scaling factors to represent speed transitions.

[0097] The flowchart in Fig. 9 shows a DWT for traffic information in block units, and the procedure of pre-processing and post-processing. Step 20 The processing up to step 28 shows the preprocessing until the input data in multiples of 2 N is prepared from the traffic information in block units. Traffic information in units of traffic is rounded at intervals equivalent to the position resolution (distance resolution), and rounding is performed according to the expression resolution to generate input data that is an integral multiple of ^2N . If the number of input data does not match an integer multiple of 2 ^N , add 0 or the last number as a dummy to match.

 Next, in order to reduce the absolute value of the input data, the level of each data is shifted by an intermediate value of the input data (Step 29), and the order N of the DWT is determined (Step 30). This is equivalent to determining how many of the cascaded filter circuits in Fig. 7 (a) should be used for DWT.

 [0099] Next, in the case of the 0th order (n = 0), the number of input data is determined in the order of force (step 30), and the number of input data is determined by the number of data / 2 "(step 32). The input data is decomposed into a scaling coefficient and a wavelet coefficient (step 33), wherein the number of data of the scaling coefficient and the number of wavelet coefficients are each half of the number of input data.

[0100] The obtained scaling coefficient is stored before the data, and the wavelet coefficient is stored after the data (step 34). If n <N (step 35), return to step 32, increase the order by one, and determine the number of input data by the number of data / 2 ⁿ . At this time, only the scaling factor stored ahead in step 34 is the next input data.

[0101] Step 32—Repeat the process of Step 34 until n = N is reached. In this process, if the number of input data is 2 ^N , the scaling factor is one. Further, when the number of input data is m × ^{2N, the} number of scaling coefficients is m.

 [0102] Next, the data generated by the DWT is decomposed into bit planes (step 36), and the binary bit data is arithmetically encoded (step 37).

Figure 10 shows one block of traffic information input data (a) adjusted to Na (= ^2N ) by adding dummy to Nb valid data, and generated by applying Nth-order DWT to this input data. The resulting scaling coefficient and wavelet coefficient (b) and the result of bit plane decomposition of the scaling coefficient and wavelet coefficient (c) are shown. This bit-plane-decomposed data becomes more important as it goes to the upper stage (that is, as the order becomes higher) and as it goes to the left (that is, as it goes to the upper digit). Therefore, as shown in Fig. 11, by removing the lower L digits and sending bit plane data of order n or more to the receiver, the essence of traffic information can be obtained. The receiver can transmit the traffic information with a coarse resolution enough to know the traffic situation.

 [0103] Fig. 12 shows transmission data (b) in which one block of traffic information is represented by a DWT coefficient, and its parameter information (a). The parameter information (a) contains the length of the corresponding block, the number of data Na (the number of divisions of the corresponding block), the number of valid data Nb, the final order of DWT N, and the minimum order of DWT included in the data for transmission. The DWT transmission order n and the level shift L indicating the number of digits excluded by the transmission data are included. The transmission data (b) includes the Nth-order scaling coefficient with the lower L digits removed and the Nth to nth-order wavelet coefficients. By changing the values of Na, N, n, and L for each block, the compression ratio for each block can be changed.The compression ratio set in <Compression ratio setting for each block> is It can be realized by changing these parameters. It should be noted that the program processing becomes easier if all blocks have the same Na.

 [0104] The orthogonal transform encoding unit 19 constitutes an encoding unit that performs encoding by orthogonal transform in units of blocks on the sampled data included in the blocks.

 <Block noise reduction processing>

 The block noise reduction processing unit 17 reduces block noise by the following methods (1), (2), and (3).

 [0105] (1) The value at the block boundary is stretched as it is, and compression-encoded to include a part outside the boundary (referred to as "boundary value stretching method"). At the time of restoration, information outside the block boundary is discarded.

 (2) Encode and compress data including data slightly deviating from the boundaries of the original blocks (referred to as “out-of-bounds encoding method”). At the time of restoration, information outside the block boundary is discarded.

 (3) Define a window function whose both ends are attenuated, and perform coding so that the P-tangent block overlaps (referred to as “window function usage method”).

[0107] These methods need to encode a range wider than the original range, which leads to an increase in the amount of data, but is a necessary process for reducing block noise.

 Next, each method will be described in detail.

[0108] (1) Boundary value extension method In the boundary value extension method, as shown in FIG. 13, the traffic information range (dotted line range, hereinafter referred to as “encoding data”) for sampling input data for generating transmission data (encoded data) of the target block K, as shown in FIG. Traffic information range) to the outside of the range of the target block K, the traffic information value in the upstream expanded range is set to the value at the upstream boundary of the target block K, and the downstream The value of traffic information in the extended range is set to the value at the downstream boundary of the target block K.

 [0109] The flowchart in Fig. 14 shows a coding procedure in this system. First, the number of blocks M of traffic information to be provided is obtained (step 40), and the traffic information of block Κ is obtained in order from the block with the block number K = l (step 41) (step 42), and both ends of block Κ are obtained. The value of the part is used as the value of the traffic information of the extended range generated outside the block (step 43), and the traffic information of the traffic information range for encoding including this extended range is targeted for <orthogonal transform coding process>. The orthogonal transformation described in (1) is performed (step 44). This process is repeated for all traffic information blocks (steps 45 and 46).

 [0110] To the parameter information of the DWT data generated in this way, as shown in Fig. 15, the number Ma of data in the extended range on the upstream side and the number Mb of data in the extended range on the downstream side are added.

 (2) Out-of-bounds coding method

 In the out-of-bounds coding method, as shown in Fig. 16, the traffic information range for coding of the target block K (the range indicated by the dotted line) is extended outside the range of the target block K, and adjacent blocks that fall within the extended range. Is used as the traffic information in the traffic information range for the code block of the target block K.

 [0111] The flowchart in Fig. 17 shows a coding procedure in this system. First, the number M of blocks of traffic information to be provided is obtained (step 50), and in the order of the block power of the block number K = l (step 51), the traffic information of block と and the traffic information of the extended range of the adjacent block are obtained. Acquisition is performed (step 52), and orthogonal transform is performed on the traffic information in the coding traffic information range including the extended range (step 53). This process is repeated for all traffic information blocks (steps 54 and 55).

 [0112] The parameter information of the DWT data generated in this way includes the boundary value extension method.

As in (Figure 15), the number of data Ma in the upstream extended range and the data in the downstream extended range Add a few Mb.

 [0113] (3) Window function usage method

 As shown in Fig. 18 (b), the window function is a function in which the added value with the adjacent window function is always 1, the maximum value is 1 and the minimum value is 0, and both ends are attenuated. Here, as the window function f (k) of the target block K, it intersects the window function f (k-1) of the upstream adjacent block K-11 on the upstream boundary of the target block K, and Using the window function f (k) that intersects the window function f (k + 1) of the downstream adjacent block K + 1 on the downstream boundary of, the traffic information of the target block K in the traffic information area for coding is The traffic information of the upstream adjacent block K-1, target block K, and downstream adjacent block K + 1 is multiplied by the window function fk.

 [0114] The flowchart in Fig. 19 shows a coding procedure in this system. First, the number M of traffic information blocks to be provided is obtained (step 60), and the traffic information of the block Κ and the traffic information of the necessary adjacent blocks are obtained in order from the block with the block number K = l (step 61). Then, the traffic information value at each sampling point of the traffic information is multiplied by a window function (step 63), and the obtained traffic information is subjected to an orthogonal transform as traffic information in the traffic information range for encoding (step 63). Step 64). This process is repeated for all blocks of the traffic information (steps 65 and 66).

 [0115] In the parameter information of the DWT data generated in this way, as shown in Fig. 20, the window function definition used for generating the traffic information in the traffic information range for encoding is added. Various types of window functions, such as a trapezoidal window, a triangular window, and a trigonometric window, can be used, and the identification information of the used window function is described in parameter information from among several predefined window functions. I do.

 [0116] As described above, the traffic information of each block on which the block noise reduction processing has been performed and the orthogonal transform coding has been performed is transmitted to the data transmitting unit 18 together with the road shape data. The road shape data may be subjected to variable-length encoding in the variable-length encoding processing unit 18 in order to compress the data amount. This variable length encoding method is described in detail in the above-mentioned Japanese Patent Application Laid-Open No. 2003-23357.

The data transmitting unit 18 transmits the traffic information and the road shape data to the information use device 40. The traffic information and the road shape data (road reference data) are received by the data receiving unit 41 constituting the acquiring unit that acquires the traffic information transmitted from the information transmitting device 10. Figure 21 shows a data structure of road shape data (a), block marker information (b), and traffic information (c) transmitted to the information utilization device 40. The block marker information (b) includes the shape identification number of the target road included in the road shape data (a), the number of traffic information blocks of the target road, the node number of the node where the block marker is set, and , And the distance between the block markers. The traffic information (c) includes the shape identification number, the information type of the traffic information, the number of traffic information blocks, the parameter information of each block shown in FIG. 12 (a), FIG. 15, and FIG. 12 (b) and the traffic information of each block subjected to the orthogonal transformation.

 [0118] When the road shape data is variable-length coded, the equidistant resampling is performed without adding the block marker position to the node (however, the resampling length of the section changes depending on the curvature of the road section). If the encoding is performed using only the nodes set in, the effect of data compression will increase. Therefore, in this case, as shown in FIG. 22, the block marker position is represented by the distances D1, D2, and D3 from the node on the left side set by the equidistant resampling. The number of bits required to display D1, D2, and D3 is given by d (m) where the resolution required to specify Dl, D2, and D3 is d (m).

 Required number of bits = roundup [log (L / d)]

 Where, L: Risampnore length (m)

 If d = 3m (the distance traveled by the vehicle in about 0.1 second), if L is 10m, 2 bits are enough, and if L is 160m, 6 bits are needed If L is 640 m, 8 bits are required. FIG. 23 shows the relationship between the resampling length and the number of bits required to display the distance between a node and a block marker. FIG. 24 shows road shape data including the identification information of the block marker and information on the distance from the node (the value of D) following the position information of the node.

 [0119] The information utilization device 40 that has received the traffic information and the road shape data sends the road shape data and the block marker information to the shape encoded data decoding unit 42, and sends the traffic information to the traffic information encoded data decoding unit 48. send.

[0120] The traffic information encoded data decoding unit 48 obtains the orthogonal transform coefficient of each block, and decodes the traffic information in block units according to the procedure shown in FIG. The traffic information coded data decoding unit 48 decodes traffic information in units of blocks and reproduces sampled data. Communication information decoding unit).

[0121] The order N of the DWT is read from the parameter information of the received traffic information (step 70), n is set to N-1 (step 71), and the number of input data is determined by the number of data / ²ⁿ (step 71). 72). Next, IDWT is performed by the filter circuit shown in FIG. 8 (b) using the front of the input data as a scaling coefficient and the rear of the input data as a single bullet coefficient, and the first-order lower-order scaling coefficient is reconstructed. (Step 73).

[0122] If n> 0 or if the time is within the time limit, the process returns to step 72, decrements n by 1, and repeats steps 72 and 73 (step 74). If n = 0 and IDWT is completed, the data is reverse-shifted by the level shifted by the transmitting side to restore traffic information in block units (step 77). Also, can a time limit IDWT process has passed, exit IDWT, using the traffic information data obtained for displaying the traffic information with lower resolution, sets the time resolution to 2 ^[pi times (step 76), the inverse shift is executed to restore the averaged block-by-block traffic information (step 77).

 [0123] When the block noise reduction processing unit 49 performs the boundary value expansion method or the out-of-bounds coding method block noise reduction processing on the transmitting side, the block noise reduction processing unit 49 calculates the target block from the restored value. By extracting only the information of the range, the traffic information of each block is obtained. In addition, if the transmitting side performs block noise reduction processing using the window function, the restored value of the target block に is added to the value of the block (Κ1-1) restored before the target block Κ. Then, by repeating this process, traffic information of each block is obtained.

 On the other hand, if the road shape data is variable-length coded, the road shape data is decoded by the shape coded data decoding unit 42, and is restored by the shape data restoration unit 43.

 The position specifying unit 44 specifies the position of the target road represented by the road shape data on the map of the digital map database (Β) 45 by performing position specification.

 <Distance deviation correction processing>

The blocking position specifying unit 46 calculates the latitude and longitude of the block marker position from the position of each node specified on the target road and the block marker information, and specifies the block section. FIG. 26 schematically illustrates this processing. Fig. 26 (a) shows the road shape data generated by the information transmitting device 10 using the map data of the digital map database (A) 12. (Here, the block marker positions (BM1, BM2, BM3) are set as nodes). FIG. 26 (b) shows a state in which the information utilization device 40 represents the node positions included in the road shape data on the map of the digital map database (B) 45. As shown in FIG. 26 (c), the position specifying unit 44 positions these nodes on the road in the digital map database (B) 45 by position specification. The block position specifying section 46 calculates the latitude and longitude of the block marker positions (BM1, BM2, BM3) positioned on this road based on the data of the digital map database (B) 45, and specifies the block section.

 [0126] The block-by-block correction coefficient calculation unit 7 calculates the distance (Bd) of each block along the road using the data of the digital map database (B) 45, and displays the distance (Bd) and the block marker information. The correction coefficient for this block is calculated from the ratio of the distance to the block marker of the corresponding block. When the distance transmitted from the information transmitting device 10 is applied to the block, the distance needs to be corrected with the correction coefficient.

 [0127] The block-by-block unit distance correction unit 50 corrects the length of the corresponding block included in the parameter information with a correction coefficient, and calculates the corrected length as the number of data Na of the block (the number of divisions of the corresponding block). The distance between each of the sampling points is obtained by dividing the block, and the blocking position specifying unit 46 specifies the position of each of the sampling points included in the block whose position has been specified. Then, the traffic information data of this block is assigned to each sampling point to reproduce the traffic information.

 As shown in FIG. 22, when the block marker does not match the node, the distance between the node nl and the node n2 is calculated using the distance between the block markers included in the block marker information and the distances Dl and D2. Calculates the distance N1 to the road, and calculates the distance N2 along the road from the node nl to the node n2 specified for the road in the digital map database (B) 45, and calculates the correction coefficient from the ratio of N2 to N1. . Then, Dl and D2 are corrected by the correction coefficient, and a point separated by D1 corrected by the node nl force is set as one boundary, and a point separated by D2 corrected from the node n2 is set as the other boundary, and the block is specified.

[0129] Further, when the accident occurrence position is reported by the distance from the reference node, the block-by-block unit distance correction unit 50 corrects the distance with a correction coefficient and stores the distance on the road in the digital map database (B) 45. From the specified reference node, a point separated by the corrected distance is specified as an accident occurrence point. [0130] The traffic information superimposing unit 51 sequentially superimposes the restored block-unit traffic information on the target road, and the information utilization unit 52 utilizes this traffic information.

 As described above, in this traffic information generation method, the traffic information on the target road is divided into small blocks and encoded, so that the load on the program is small, and the encoding / decoding process is performed. The memory size of the work memory used can be small. Therefore, the encoding / decoding unit can be configured by a semiconductor chip or the like.

 [0131] Also, since the compression ratio of traffic information can be changed in small block units, the detail of the traffic information can be set as necessary.

 In addition, it is possible to correct the deviation in the distance direction of the road by using the boundary position of the traffic information block, and to convey information with high accuracy.

 [0132] In addition, traffic information in small block units can be efficiently encoded and decoded by streaming processing or pipeline processing in which an input block is processed and output before the next block is input. It is possible.

 [0133] In the traffic information sampling and block division, after sampling is performed, the obtained sampled data may be divided into a plurality of blocks, or the block division position may be determined before sampling. May be determined, and then sampling may be performed at predetermined intervals in each block.

 [0134] <Modifications>

So far, the case where the length of each block is set constant has been described. However, the traffic information block may be divided at a point where the traffic flow is likely to change (a bottleneck intersection, in front of a famous facility, etc.). Figure 27 shows an example of setting block strength at a famous intersection or a bottleneck intersection. In this case, the distance between the block markers will be unequal, but by keeping the number of divisions (the number of data Na) in each block constant, or within a range not exceeding a predetermined maximum value. By setting the number of data Na, the effects of reducing the encoding / decoding processing load, adaptively changing the compression ratio, and correcting the displacement in the distance direction can be achieved. In the case of this modification, the traffic condition between important intersections is represented by traffic information of one block, so that it becomes easier to understand. In addition, it becomes possible for the information utilization device to select a block that reproduces traffic information and reproduce only the traffic conditions between the intersections that the user wants to know. [0135] Also, a case has been described above in which traffic information is divided into blocks by distance, and when a vehicle-mounted probe car provides traffic information (measurement information) to the probe information collection center, traffic information (measurement information) is not provided. Information may be divided and transmitted in units of time. If the center provides travel time traffic information, it is possible to block the traffic information in travel time units.

 [0136] Also, a case has been described above in which road shape data including a data sequence of node positions on the target road is used to convey the target road of the traffic information. However, data for identifying the target road is used. As the (road section reference data), for example, an identification code assigned to the target road section in advance, a road section identifier (link number), an intersection identifier (node number), and the like which are unified, may be used. .

 When both the providing side and the receiving side refer to the same map, the providing side transmits the latitude / longitude data to the receiving side, and the receiving side can specify a road section based on the data.

 In addition, the road map is divided into tiles and the identifiers assigned to each of them, and the key posts, road names, addresses, postal codes, etc. provided on the roads are used as the road section reference data, and the target road section of the traffic information is used. May be specified.

(Second Embodiment)

 In the second embodiment, an example is shown in which block markers are arbitrarily set at unequal intervals as in the modification of FIG. In the second embodiment, a probe car is assumed as the information transmitting apparatus, and an example suitable for collecting traffic information such as speed information by the probe car will be described.

FIG. 28 is a diagram schematically showing a first example and a second example of a method for generating traffic information according to the second embodiment. The first example is a case where the traveling direction of the probe car greatly changes by a predetermined value or more based on the output of a vehicle steering sensor such as a steering angle sensor or a gyro provided on the probe car, that is, when the vehicle turns a large angle by a predetermined angle or more during traveling. It is determined that an event has occurred at this point, and a block marker is set at this location. As shown in Fig. 28, consider the case where there is an intersection at a point between 3000m and 4000m where the setting start point of the block marker is set, and the professional car turns right here. Then, right-turn congestion occurs before this intersection It is assumed that

 [0140] Since such a place where the probe car bends greatly is considered to be a point of change in traffic conditions such as an intersection, the traffic information is compressed on a block basis by inserting a block marker here. However, it is possible to clearly determine the position where the traffic situation changes. In addition, since the block marker clearly indicates where there is a change point in traffic conditions such as an intersection, the position of the intersection is clearly grasped when calculating the waiting time for right and left turns (right and left turn costs) from the collected traffic information. It is possible to improve the accuracy of the waiting time for turning right and left. In addition, even when generating congestion information, the position of a break in the queue, such as the congestion start position and end position, can be easily determined, and the calculation of the waiting time, the end position of the queue, and the like becomes easy.

 [0141] The second example is another example in which the output of a vehicle sensor is used. When the probe car has been stopped for N minutes or more based on the output of a vehicle sensor such as a speed sensor provided in the probe car, an event occurs. Is determined, and a block marker is set at this location. For example, insert a block marker if the stop state continues for 3 minutes or more. Usually, the signal control cycle is 45 seconds to 180 seconds, and the stoppage for signal waiting is about 20 seconds to 90 seconds. The stop time is about 180 seconds at the maximum even if there is no movement for two cycles when the tip of the intersection is blocked. If the vehicle is stopped for longer than this time, it is considered that the vehicle is not on the traffic flow, such as getting on and off the taxi and waiting for people. Since such a stop is not appropriate as traffic information, a block marker is inserted to clearly indicate where the stop event occurred. This makes it possible to clearly determine the position where the running state of the probe car has changed, and to provide highly accurate traffic information.

 [0142] In the first and second examples described above, in blocks before and after a block marker set at an event occurrence point such as an intersection right turn or a stop, by changing the compression ratio of traffic information, each divided block is changed. Traffic information having an appropriate information amount can be generated. For example, by reducing the compression ratio of the upstream block located before the intersection to increase the amount of information and making the traffic information more detailed, the end of the queue such as traffic congestion during a right turn can be grasped more clearly. be able to.

FIG. 29 is a diagram schematically illustrating a third example and a fourth example of the traffic information generation method according to the second embodiment. FIG. In the third example, based on the map information of the navigation device provided in the probe car and the position of the vehicle, identification of points of interest to the user, such as the point where the probe car left the road, parking lots, stores, and amusement facilities, etc. It is determined that an event has occurred at the entry point of the target location, POI (Point Of Interest), a point on a private road or on a road inside the facility, etc., and a block marker is set at this location.

 [0144] When a car enters the POI, it must leave the public road network or drive on a private or institutional road. In general, traffic information such as traffic congestion information does not require information other than the public road network. Therefore, by inserting a block marker at each of the above points, the boundary points between the public road network and others are specified. As a result, it is possible to easily identify entry / exit positions outside the public road network, and it is possible to provide traffic information with high necessity. In addition, when traffic congestion waiting to enter a parking lot or facility occurs, when generating traffic congestion information, as in the first example, the position of a break in the queue, such as the traffic congestion start position or end position, is used. Can be easily determined, and the calculation of the waiting time and the end position of the queue becomes easy.

 [0145] In the fourth example, based on information of a communication device such as a DSRC (Dedicated Short Range Communication) type short-range wireless communication device provided in a probe car, it is determined that an event has occurred when communication occurred, and at this location This is for setting a block marker. For example, data can be transmitted and received when passing through the gate of an ETC (Electronic Toll Collection) system using DSRC narrow-area communication provided at a tollgate on an expressway, or at a DSRC system provided at the entrance of a parking lot or facility. Insert a block marker when it occurs.

 [0146] Due to traffic congestion at the toll booth, the traffic condition changes before and after the toll booth, and at the entrance and exit of the interchange connected to the toll booth. At the entrance to parking lots and facilities, traffic conditions may change due to congestion waiting for entry. By inserting a block marker at such a point, it is possible to clearly determine the position where the traffic situation changes. In addition, it is possible to clearly distinguish entrance points such as POIs and to clearly distinguish the public road network from other places such as within P〇I, and provide useful traffic information.

FIG. 30 is a block diagram showing a configuration of an information transmitting device 110 for providing traffic information and an information utilizing device 40 for utilizing the provided traffic information in the second embodiment. The information transmission device 110 is a vehicle-mounted probe car, and has the information of the first embodiment shown in FIG. The configuration of the information transmitting device 10 is partially changed. Note that, in FIG. 30, the same components as those in FIG. 2 are denoted by the same reference numerals, and detailed description thereof will be omitted.

 [0148] The information transmitting apparatus 110 includes a GPS position detecting unit 121, a speed sensor 122, and a gyro 123 as vehicle sensors. Also, a travel locus measurement information input unit 111 which fetches the map information of the digital map database (A) 12 and the measurement information obtained by each of the vehicle sensors described above, and inputs the information as the travel locus measurement information of the probe car; A traveling locus shape extracting unit 113 which generates shape data of a traveling locus of a probe car relating to a target road and P〇I of traffic information from output information of the input unit 111, the traveling locus measurement information input unit 111, a digital map Database (A) 12 and a measurement information blocking determination unit 114 that determines the division position of measurement information to be blocked based on output information of each vehicle sensor and generates traffic information in block units, and the traveling trajectory shape extraction unit 113 And a block position tracking unit 115 for adding a block marker to the shape data of the traveling locus based on the output information of the measurement information blocking determination unit 114. Further, information from the steering wheel angle sensor 124 and the DSRC communication unit 125 is input to the measurement information blocking determination unit 114.

 [0149] Information transmitting apparatus 110 constitutes an encoder from the viewpoint of generating encoded data, and information utilization apparatus 40 constitutes a decoder from the viewpoint of restoring encoded data.

 The processing of setting the block marker in the information transmitting apparatus 110 configured as described above is performed according to the procedure shown in FIG. FIG. 31 is a flowchart showing a procedure for adding a block marker to probe car measurement information in the second embodiment.

[0150] The measurement of the speed and the like by the probe car is repeated every unit time (or at fixed distance intervals), and the measurement data is accumulated in the buffer (step 101). When the transmission time of the probe information comes (Step 102), the measurement information blocking determination unit 114 determines the unit of the block strength to be applied (Step 103). Here, the unit of assigning the block marker is a value fixedly determined in the system or a value determined by measuring the amount of free memory of the current buffer. There are two types, fixed distance unit and fixed time unit. At first, the node number N of the road shape data of the target road is set as N = l (Step 104), the travel locus measurement information input section 111, the digital map database (A) 12 and Then, information from the vehicle sensors of the GPS position detector 121, the speed sensor 122, and the gyro 123 is input, and it is determined whether or not a predetermined event has occurred at the node N (step 105).

 [0151] Here, as described in the first example to the fourth example, the predetermined event may be (1) the output of the vehicle sensor (the steering angle of the vehicle, the gyro, the GPS azimuth, etc.) (2) When it is determined from the output (speed etc.) of the vehicle sensor that it has stopped for a predetermined time or more, (3) From the position identification result of the shape data of the traveling locus , "Away from the road", "P〇I (parking lot, etc.) entrance", "Private road or in-facility road", or determined to be a key point in traffic at major intersections or in front of large-scale facilities (4) When communication with the ETC system or DSRC system occurs based on the information in the DSRC communication unit.

 [0152] If a predetermined event has occurred (Yes in step 106), the measurement information blocking determination unit

 The 114 sets a block marker at the location where this event has occurred, and generates block marker information (step 107). Then, it is determined whether or not the distance or the time interval from the previous marker setting position exceeds the determined giving unit (step 108). On the other hand, if no event has occurred in step 106, the assignment unit determination is performed in step 108 without generating the block marker in step 107. If it exceeds the assignment unit (Yes in Step 109), block marker information in a fixed assignment unit is generated (Step 110). Thereafter, it is determined whether the processing has been completed for all nodes of the road shape data of the target road (step 111). On the other hand, if the number does not exceed the assignment unit, the end of all nodes is determined in step 111 without generating the block marker in step 110

If the block marker input determination and generation processing have not been completed for all the nodes of the road shape data of the target road, the node number is incremented by one as the node number N = N + 1 (step 112), and step 105 Then, the processing of steps 105-110 is repeated for the next node. On the other hand, when the processing of all the nodes is completed, the compression ratio determination unit 16 determines the compression ratio of the traffic information for each block divided by the block marker generated by the measurement information block determination unit 114, After performing the block noise reduction processing in the block noise reduction processing unit 17, the orthogonal transform coding processing unit 19 performs DWT The data is compressed by performing an orthogonal transformation code processing (step 113). Further, based on the block marker information generated by the measurement information blocking determining unit 114, the block position marker adding unit 115 adds the position information of the block marker to the shape data of the running locus generated by the running locus shape extracting unit 113. Add (step 114).

 [0154] When the traffic information is divided into small blocks and compressed in block units, measurement information such as speed and unit section travel time is leveled with the compression. It may be difficult to make a decision, and when generating traffic congestion information, etc., the end position of the event may be discriminated. Therefore, in the second embodiment, when an event corresponding to a change point in traffic conditions, such as an intersection turning right or left or entering a POI, occurs, a change in traffic condition is set by setting a blocker force at the corresponding position. Can be easily determined. In addition, in each block divided by the block marker, appropriate and efficient compression processing can be performed, and both reduction of the data amount of traffic information and improvement of usefulness can be achieved.

 [0155] Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. Is.

 [0156] This application is based on a Japanese patent application filed on October 21, 2003 (Japanese Patent Application No. 2003-360630) and a Japanese patent application filed on April 14, 2004 (Japanese Patent Application No. 2004-118744). , The contents of which are incorporated herein by reference.

 Industrial applicability

 [0157] The traffic information generation method of the present invention can reduce the load on the software side and the hardware side on the side that generates traffic information and on the side that uses traffic information. It can be widely used when generating traffic information and probe information.

 [0158] The device of the present invention can be applied to a center device of a traffic information providing system, a probe car in-vehicle device that provides measurement information, and the like. It can be widely applied to information terminals such as center devices, car navigation devices, personal computers, PDCs, and mobile phones.

Claims

The scope of the claims

 [1] A traffic information generation method for sampling traffic conditions of a target road at predetermined intervals along a road,

 Dividing the array of sampled data into a plurality of blocks;

 Performing encoding by orthogonal transformation on the sampled data included in the block in units of the block.

2. The traffic information generation method according to claim 1, wherein the number of the sampled data included in each of the blocks is set to be equal to or less than a predetermined upper limit number.

3. The traffic information generation method according to claim 2, wherein the number of the sampled data included in each of the blocks is set to be constant.

4. The traffic information generating method according to claim 1, wherein the target road is divided at regular intervals, and the blocks are generated corresponding to the divided sections.

5. The traffic information according to any one of claims 1 to 3, wherein the target road is divided at unequal distance intervals with a selected point as a boundary, and the blocks are generated corresponding to the divided sections. Generation method.

 [6] The traffic information generation method according to claim 5, wherein an intersection or a point of a facility is selected as the boundary.

 7. The traffic information generating method according to claim 1, wherein the block is generated by dividing the sampled data into time units.

[8] In the case where the sampled data is measurement information measured by a probe car vehicle-mounted device, the measurement information is divided into a plurality of pieces according to a time zone of a measurement time, and the block is generated based on the divided measurement information. The method for generating traffic information according to any one of claims 1 to 3.

[9] When the sampled data is measurement information measured by the on-board probe car, the travel information on the on-board probe car and the position on the map information to which the position of the on-board probe car is associated The block marker according to any one of claims 1 to 3, wherein a block marker indicating a boundary of the block is set based on at least one of information and communication operation information in a communication unit mounted on the probe car vehicle-mounted device. Traffic information Generation method.

 [10] The block marker is set based on at least one of the travel information, the position information, and the communication operation information when a predetermined event occurs in traveling of the probe car on-board unit. Method of generating traffic information described in 9.

11. The traffic information generation method according to claim 1, wherein a data compression ratio in encoding is set for each block.

12. The traffic information generation method according to claim 11, wherein the data compression ratio is changed according to an average speed of the block represented by the sampled data.

13. The traffic information generation method according to claim 11, wherein the data compression ratio is changed according to a change rate between the blocks of the average speed of the block represented by the sampled data.

14. The traffic information generation method according to claim 11, wherein the data compression ratio is changed according to an event occurring in a section corresponding to the block.

15. The traffic information generation method according to claim 11, wherein the data compression ratio of a block including the measurement information of the probe car on-vehicle device as sampling data is changed according to an event measured by the on-vehicle robe car device.

16. The traffic information generation method according to claim 11, wherein the data compression ratio of a block including the measurement information as sampling data is changed according to a measurement time of the measurement information measured by the probe car on-board unit.

 17. The traffic information generation according to claim 11, wherein the data compression ratio of the block including the measurement information measured by the on-board probe car is changed depending on whether or not the measurement point is around a specified position. Method.

 18. The method according to claim 1, wherein, when performing the encoding in block units, the range of the block is extended, and encoding is performed on the sampled data of the block including the sampled data of the extended part. How to generate traffic information.

19. The traffic information generation method according to claim 18, wherein the value of the sampled data of the extended portion is made to match the value of the sampled data at the original boundary of the block.

20. The traffic information generation method according to claim 18, wherein a value of the sampled data of the extended portion is made to match a value of the corresponding sampled data of a block adjacent to the block.

[21] The value of the sampled data of the extended portion is matched with the value of the corresponding sampled data of a block adjacent to the block, and the sampled data of the block including the extended portion is multiplied by a window function; 19. The traffic information generation method according to claim 18, wherein the obtained value is used as sampling data of the block.

 22. The traffic information generation method according to claim 1, wherein position information indicating a boundary of the block is added to the road reference data for specifying the target road to be a part of the traffic information.

 [23] A traffic information reproduction method in which traffic conditions of a target road are sampled at predetermined intervals along a road,

 Dividing the array of sampled data into a plurality of blocks and performing coding on the blocks to obtain traffic information generated;

 Decoding the traffic information on a block-by-block basis to reproduce sampled data.

24. The traffic information reproducing method according to claim 23, wherein in reproducing the sampled data, the traffic information is output in association with position information.

25. The traffic information reproducing method according to claim 23, wherein in reproducing the sampled data, the traffic information is displayed on a display unit in association with position information.

[26] A program for causing a computer to execute each step of the traffic information generating method according to any one of claims 122.

[27] A program for causing a computer to execute each step of the method for reproducing traffic information according to any one of claims 23 to 25.

[28] A traffic information generation device that samples traffic conditions of a target road at predetermined intervals along a road,

 A block dividing unit that divides the array of sampled data corresponding to the traffic condition into a plurality of blocks;

 A traffic information generation apparatus, comprising: an encoding unit that performs encoding by orthogonal transformation on the sampled data included in the block in units of the block.

[29] A traffic information blocking unit that divides an array of sampled data obtained by sampling the traffic condition of the target road into a plurality of blocks, A block-by-block compression ratio determining unit that determines a compression ratio in encoding of the sampled data included in the block,

 A block noise reduction processing unit that performs processing for reducing block noise occurring at the block boundary during decoding;

 A traffic information generating apparatus, comprising: an orthogonal transform encoding processing unit that performs encoding by orthogonal transform on a block-by-block basis with respect to the sampled data of the block on which block noise reduction processing has been performed.

 [30] A code generated by the orthogonal transformation code processing unit, comprising: a block position marker adding unit that adds block-aligned position information indicating a block boundary to the road reference data specifying the target road. 30. The traffic information generating device according to claim 29, wherein the traffic information generating device provides the traffic data and the road reference data to which position information of the block marker is added.

 31. The traffic information generating apparatus according to claim 30, wherein the block position marker adding unit divides the target road at a predetermined distance interval, and sets the block marker corresponding to the divided section.

 [32] The block position marker adding unit, when the sampled data is measurement information measured by a probe car on-board device, divides the measurement information at predetermined time intervals and associates the measurement information with the divided measurement information. 31. The traffic information according to claim 30, wherein the block marker is set by

[33] The block position marker adding unit, when the sampled data is measurement information measured by a probe car vehicle-mounted device, associates travel information in the probe car vehicle-mounted device with the position of the probe car vehicle-mounted device. 31. The traffic information generation apparatus according to claim 30, wherein the block marker is set based on at least one of position information on the map information and communication operation information in a communication unit mounted on the probe car on-board unit. .

 [34] A traffic information reproducing apparatus that samples traffic conditions of a target road at predetermined intervals along a road,

 An acquisition unit that divides an array of the sampled data corresponding to the traffic condition into a plurality of blocks and performs encoding in units of the blocks to acquire traffic information generated;

A reproducing unit that reproduces the sampled data by decoding the traffic information in block units; A traffic information reproducing device comprising:

[35] a receiving unit that receives traffic information obtained by dividing the sampled data indicating the traffic condition of the target road into blocks and encoding the road, and road reference data indicating the boundary positions of the target road and the block;

 A traffic information decoding unit that decodes the traffic information in block units and reproduces sampled data;

 A block noise reduction processing unit that obtains sampled data included in the range of each block except for the sampled data that has been removed for block noise reduction from the reproduced sampled data,

 A block-by-block correction coefficient calculating unit that calculates a correction coefficient of a shift occurring in a distance direction of the target road using information on a boundary position of the block included in the road reference data;

 A traffic information reproducing apparatus comprising: a block-by-block unit distance correction unit that specifies an accurate position of the block on a target road using the correction coefficient and positions the sampled data at a sampling position of the block.