Method and apparatus for determining a posted speed limit value for a map road

Abstract

The application provides a method for determining a marked speed limit value for a map road, the method comprising the following steps: obtaining speed limit sign information of each map road, the speed limit sign information comprising a real speed limit value of a speed limit sign and an effective range thereof; obtaining road type information of each map road, and determining a derived speed limit value based on the road type information; and determining a marked speed limit value for each map road based on the speed limit sign information and the road type information, and in at least some cases, when a marked speed limit value is determined for a missing road section of the speed limit sign information of the map road, a value source is selected from the real speed limit value and the derived speed limit value with different priorities. The application also provides a device for determining a marked speed limit value for a map road and a computer program product. Through the speed limit marking scheme provided by the application, all roads in the map data have legal and compliant speed limit values for use by a navigation system and an automatic driving function.

Description

Technical Field

[0001] This application relates to a method for determining the marked speed limit value for roads on a map, and also to an apparatus and a computer program product for determining the marked speed limit value for roads on a map. Background Technology

[0002] In some areas, road networks lack full coverage of speed limit signs, and map data typically only records information on existing speed limit signs. For road sections lacking signs, how to inform drivers of legal speed limits and how to enable autonomous vehicles to control their speed appropriately have become pressing issues. Currently, the industry lacks unified speed limit labeling rules for road sections with missing signs, limiting the reliability of navigation and intelligent driving functions in these areas.

[0003] Therefore, the existing map road speed limit marking scheme still has obvious shortcomings. Summary of the Invention

[0004] The purpose of this application is to provide a method for determining the marked speed limit value for roads on a map, an apparatus for determining the marked speed limit value for roads on a map, and a computer program product, so as to at least solve some of the problems in the prior art.

[0005] According to a first aspect of this application, a method for determining marked speed limits for roads on a map is provided. The method includes the following steps: obtaining speed limit sign information for each road on the map, the speed limit sign information including the actual speed limit value and its effective range of the speed limit sign; obtaining road type information for each road on the map, and determining a derived speed limit value based on the road type information; and determining marked speed limits for each road on the map based on the speed limit sign information and the road type information, wherein, at least in some cases, when determining marked speed limits for road segments where speed limit sign information is missing, the source of the assignment is selected from the actual speed limit value and the derived speed limit value with different priorities.

[0006] This application specifically includes the following technical concept: Through the aforementioned speed limit labeling mechanism, a reasonable speed limit solution can be provided for all map roads based on the actual distribution of existing speed limit signs and combined with legal and compliant derivation logic. Thus, all map roads can have legal and compliant speed limits, which can be used by navigation systems and autonomous driving functions. Furthermore, by selecting the assignment source from real and derived speed limit values ​​in a differentiated manner, the speed limit labeling rules can be personalized according to the complexity of the road environment. While ensuring the accuracy of speed limit values ​​and regulatory compliance, the computational overhead in the speed limit labeling process is effectively reduced.

[0007] In one exemplary embodiment, selecting the assignment source from the actual speed limit value and the derived speed limit value with different priorities includes: for highways or urban expressways, when determining the marked speed limit value for road sections with missing speed limit sign information, the actual speed limit value is preferentially used as the assignment source; for ordinary urban roads, when determining the marked speed limit value for road sections with missing speed limit sign information, the derived speed limit value is preferentially used as the assignment source.

[0008] In one exemplary embodiment, the method further includes: for road segments on the map where speed limit sign information exists, directly using the actual speed limit value contained in the speed limit sign information as the labeled speed limit value; and / or, for cases where all road segments on the entire map lack speed limit sign information, directly using the derived speed limit value as the labeled speed limit value for each road segment on the map.

[0009] In an exemplary embodiment, the actual speed limit value is used as the source of the speed limit sign information for road sections lacking speed limit sign information by: expanding the scope of the speed limit sign to determine the expanded scope of the speed limit sign; for road sections lacking speed limit sign information that fall within the expanded scope, the actual speed limit value of the speed limit sign corresponding to the expanded scope is used as its marked speed limit value.

[0010] In an exemplary embodiment, for highways or urban expressways, the effective range of speed limit signs is extended in the following ways: the starting point of the effective range of the first speed limit sign on the main road is extended forward to the beginning of the main road; the ending point of the effective range of the previous speed limit sign on the main road is extended backward to the location where the next speed limit sign appears; if dedicated speed limit sign information is missing for tunnels or bridges on the main road, the effective range of the last speed limit sign before entering the tunnel or bridge is extended backward to cover the tunnel or bridge and the road segment after its exit, until the next speed limit sign appears; and / or, if dedicated speed limit sign information exists for tunnels or bridges on the main road, the effective range of the last speed limit sign before entering the tunnel or bridge is extended backward to cover the road segment after its exit, until the next speed limit sign appears.

[0011] In an exemplary embodiment, for highways or urban expressways, in the scenario of an entrance ramp, the deduced speed limit value is used as the marked speed limit value for the section of road before the first speed limit sign on the ramp; in the scenario of an exit ramp, the actual speed limit value of the dedicated speed limit sign for that ramp on the main road is used as the marked speed limit value for the section of road before the first speed limit sign on the ramp; in the scenario of a ramp bifurcation, the merged ramp adopts the marked speed limit value of the main ramp into which it is merged; and / or, in the scenario of a ramp bifurcation, the main ramp after the bifurcation adopts the marked speed limit value of the ramp before the bifurcation, and the branch ramp after the bifurcation adopts the deduced speed limit value as the marked speed limit value.

[0012] In an exemplary embodiment, for ordinary urban road grades, the derived speed limit value is preferentially used as the assignment source in the following cases: The section of road on the map before the first speed limit sign appears; The section of road after the intersection and before the next speed limit sign appears; The section of road after the speed limit sign is lifted and before the next speed limit sign appears; and / or The section of road after the exit of a tunnel or bridge and before the next speed limit sign appears; For ordinary urban roads, the effective range of speed limit signs is limited in the following ways: - When a speed limit sign does not specify that its effective range is valid for the entire road on the map, the endpoint of the effective range of the speed limit sign is set to the location of the first intersection that appears thereafter.

[0013] In an exemplary embodiment, the road type information includes: road grade, road link attribute, number of lanes, and road toll type. The derived speed limit is determined based on the road type information by: pre-configuring a derived speed limit table based on traffic regulations or road design standards; and querying a speed limit that matches the road type information from the preset derived speed limit table, and using it as the derived speed limit.

[0014] According to a second aspect of this application, an apparatus is provided for determining marked speed limits for roads on a map. The apparatus includes a memory and a processor. The memory stores computer program instructions, which, when executed by the processor, enable the processor to perform the method described according to the first aspect of this application.

[0015] According to a third aspect of this application, a computer program product is provided, comprising computer program instructions, wherein, when executed by a processor, the computer program instructions enable the processor to perform the method according to a first aspect of this application. Attached Figure Description

[0016] The principles, features, and advantages of this application will be better understood below with reference to the accompanying drawings. The drawings include: Figure 1 A flowchart is shown illustrating a method for determining labeled speed limits for roads on a map according to an exemplary embodiment of this application; Figure 2 A flowchart is shown of a method for determining labeled speed limit values ​​for roads on a map according to another exemplary embodiment of this application; Figure 3This diagram illustrates the process of determining speed limit values ​​for map roads in an exemplary scenario. Figure 4 This diagram illustrates the process of determining labeled speed limits for roads on a map in another exemplary scenario; Figure 5 This diagram illustrates the process of determining labeled speed limits for roads on a map in another exemplary scenario; Figure 6 This diagram illustrates the process of determining labeled speed limits for roads on a map in another exemplary scenario; and Figure 7 A schematic diagram of an apparatus for determining speed limit values ​​for map roads according to an exemplary embodiment of this application. Detailed Implementation

[0017] To make the technical problems to be solved, the technical solutions, and the beneficial technical effects of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and several exemplary embodiments. It should be understood that the specific embodiments described herein are only for explaining this application and are not intended to limit the scope of protection of this application.

[0018] Figure 1 A flowchart illustrating a method for determining labeled speed limits for roads on a map according to an exemplary embodiment of this application is shown. The method includes steps S1 to S3.

[0019] In step S1, the speed limit sign information of each map road is obtained. The speed limit sign information includes the actual speed limit value of the speed limit sign and its effective range.

[0020] In this context, a map road refers to an actual road unit represented by map data, which in a high-resolution map is represented, for example, as a road link (road line). Each map road corresponds to a continuous segment of an actual physical road, and has a unique road identifier, geometry, length, and related attribute information, such as road class, number of lanes, and direction of travel.

[0021] In one embodiment, speed limit sign information can be read directly from map data. In another embodiment, speed limit sign information can also be obtained through other channels. For example, official speed limit data can be obtained from traffic management departments, or speed limit sign information for each road segment can be identified and collected through onboard sensors (such as cameras) of surveying vehicles.

[0022] The speed limit information included on the speed limit sign may be the actual speed limit value, such as the maximum speed limit value specified for a specific direction of traffic, the minimum speed limit value, or a speed limit range (such as "60-100km / h"). The actual speed limit value is usually clearly indicated by numbers or words on the speed limit sign, representing the legal speed requirement that vehicles must comply with within the area covered by the sign.

[0023] The scope of effect included in speed limit sign information refers to the road section where the speed limit specified by the sign is effective. This scope information can be pre-stored in map data in the form of start and end point coordinates, distance length, or road segment identification.

[0024] In one embodiment, the speed limit sign will directly indicate the effective distance, such as an additional note below the sign saying "1km ahead". In this case, the effective range is the interval extending from the position of the sign to that distance.

[0025] In one embodiment, a speed limit sign (such as "Speed ​​Limit Removal") is placed after the speed limit sign, and the road segment between the two signs is the area of ​​effect of the former sign.

[0026] In one embodiment, the speed limit sign itself does not explicitly indicate its scope of application. The map data provider may determine a reasonable scope of application based on rules such as road traffic regulations or road sign design specifications. For example, the scope of application may be set to extend from the location of the sign to the subsequent ramp merging node, intersection, or location where the road grade changes.

[0027] In one embodiment, the scope of the speed limit sign may also be divided by lane, meaning that different lanes may be subject to different speed limits, and this information will also be recorded in the map data.

[0028] In step S2, road type information for each map road is obtained, and speed limit values ​​are derived based on the road type information.

[0029] In this context, deriving speed limits refers to the reasonable speed limits required for different types of roads based on traffic regulations and road design standards, rather than speed limits directly read from speed limit signs. Its purpose is to provide a legally compliant basis for speed limits on road sections where speed limit signs are missing.

[0030] In one embodiment, road type information may include: road grade, road link attribute, number of lanes, and road toll type. Different road types can be understood as different combinations of the above information.

[0031] For example, road classifications in map data are typically identified by "road class," with different numbers representing different road levels. For instance, expressways and urban expressways correspond to road classes 0 and 1 respectively; national highways, provincial highways, and urban arterial roads correspond to 2, 3, and 5 respectively; county roads and urban secondary arterial roads correspond to 4 and 6 respectively; and ordinary roads, rural roads, county and village roads, and side roads correspond to 7 to 10. Road link attributes include, for example, the main road itself, roads within service areas, roads within parking lots, ramps, auxiliary roads, roundabouts, and other roads.

[0032] In one embodiment, speed limits can be batch-determined for map roads corresponding to various road types by combining traffic regulations and road design standards. Specifically, a deduced speed limit table can be pre-configured based on regulations and standards such as road traffic safety laws, urban road engineering design specifications, and highway speed limit sign design specifications of specific countries or regions. This table stores legal and compliant speed limits applicable to different road types, indexed by road grade, number of lanes, road link attributes, and toll type. When determining the deduced speed limit, the speed limit that matches the current road type information can be retrieved from the pre-set deduced speed limit table and used as the deduced speed limit for that road.

[0033] For example, a derivation speed limit table as shown in Table 1 can be pre-configured.

[0034] Table 1 In step S3, based on the speed limit sign information obtained in step S1 and the derived speed limit value determined in step S2, a labeled speed limit value is determined for each map road. At least in some cases, when determining the labeled speed limit value for road sections lacking speed limit sign information, the assignment source is selected from the actual speed limit value and the derived speed limit value with different priorities.

[0035] Here, "road segment lacking speed limit sign information" refers, for example, to a road segment that is not within the coverage area of ​​any speed limit sign, or whose coverage area cannot be determined. For example, this includes the following situations: -A complete road on the map with absolutely no speed limit signs; - Although there are speed limit signs on the roads in the map, some sections of the road are outside the scope of the speed limit signs. For example, the scope of the sign only covers a distance extending from the location of the sign in the direction of travel. The section of road beyond this distance is considered a missing section. -Speed ​​limit signs are placed on the roads in the map, but the data on the effective range of these speed limit signs is incomplete, blurry, or missing, making it impossible to determine whether a certain road segment is covered.

[0036] In the above situation, it is necessary to select the source of the assignment from the actual speed limit value (through the expansion of the scope of application) or the derived speed limit value according to the corresponding assignment rules in order to determine the marked speed limit value.

[0037] Accordingly, "the presence of speed limit signs" means that the road section is within the effective range of existing speed limit signs on the map.

[0038] In one embodiment, the actual speed limit value is used as the source of the speed limit sign information for road sections lacking this information by expanding the effective range of existing speed limit signs on the road to determine the extended effective range. For road sections lacking speed limit sign information that fall within the extended effective range, the actual speed limit value of the corresponding speed limit sign within that extended effective range is used as the marked speed limit value. This expansion process allows the coverage of speed limit signs to extend forward or backward, thereby filling in blank areas between signs or missing speed limit information at the start and end points of the road.

[0039] In one embodiment, the derived speed limit value is used as the source of the value for road segments with missing speed limit sign information in the following way: based on the road type information of the current road, the speed limit value that matches the road type information is queried from the preset derived speed limit value table, and the speed limit value is directly used as the marked speed limit value for the missing road segment.

[0040] In one embodiment, different priority rules can be applied based on road classification. For example, roads can be classified as expressways or urban expressways, and ordinary urban roads, with different priorities applied to the selection of sources for assigning speed limit sign information to road sections lacking such information.

[0041] In another embodiment, scene complexity can be assigned to all map roads based on road type information first, and different road scenes can be distinguished accordingly. The evaluation of scene complexity can take into account factors such as road grade, number of lanes, intersection density, and surrounding environment. Different rules can be applied to the priority selection of the assignment source for road scenes with higher complexity (such as urban center areas) and road scenes with lower complexity (such as suburban highways).

[0042] In one embodiment, after determining the marked speed limit for each road according to the aforementioned steps, the map data can be updated so that all road segments in the map data have corresponding marked speed limits. This update process completes the map road segments that originally lacked speed limit information with legal and compliant speed limit values, thereby forming a complete road speed limit data layer.

[0043] In one embodiment, after updating the map data, the updated map data can be provided to a navigation system or an intelligent driving system. The navigation system can provide speed limit reminders and overspeed warnings to the driver based on the marked speed limits. The intelligent driving system can plan and control vehicle speed based on the marked speed limits to ensure that the vehicle's speed on different road sections complies with traffic regulations. In this way, a complete and reliable road speed limit data foundation is provided for navigation and intelligent driving functions.

[0044] Figure 2 A flowchart illustrating a method for determining labeled speed limits for roads on a map according to another exemplary embodiment of this application is shown. Figure 2 In the illustrated embodiment, Figure 1 Step S3 is shown as further including sub-steps S31 to S35. The implementation process of steps S1 and S2 can be referred to the previous description, and will not be repeated here.

[0045] In sub-step S31, the presence of speed limit signs is first checked on different road segments of each map road. As defined above, the presence of speed limit signs means that the road segment is within the effective range of existing speed limit signs on its road. For example, if a map road is divided into three consecutive road segments A, B, and C, where road segment A is within the effective range of speed limit signs on that road, while road segments B and C are not within the effective range of any speed limit signs, then road segment A is considered to have speed limit signs, and road segments B and C are considered to be road segments without speed limit signs.

[0046] For road sections with speed limit signs, the actual speed limit value contained in the speed limit sign information can be directly used as the marked speed limit value for that road section in sub-step S32. Continuing with the above example, if road section A is within the effective range of a speed limit sign with an actual speed limit of 80 km / h, then the marked speed limit value for road section A can be directly determined as 80 km / h.

[0047] For road sections lacking speed limit sign information, sub-step S33 can further determine whether all road sections on the entire map road lack speed limit sign information. If this is the case, since it is impossible to obtain a reference for the actual speed limit value from any existing speed limit signs, for example, if no speed limit signs are set on the main road of a highway, and the other map roads connected to it are no longer of the same road level, the speed limit signs on them are also not of reference value. In this case, sub-step S34 can directly determine the derived speed limit value based on the road type information of the map road, and use the derived speed limit value as the marked speed limit value for each road section.

[0048] Conversely, if it is determined in sub-step S33 that not all road segments on the entire map are missing speed limit signs, but only some road segments are missing, then in sub-step S35, the priority of selecting the assignment source can be determined based on the road level and other information of the map road, and the assignment source can be selected from the actual speed limit value and the derived speed limit value according to the determined priority.

[0049] In one embodiment, priority setting rules can be determined according to road classification. For example, for highways or urban expressways, when determining the marked speed limit for road sections lacking speed limit sign information, the actual speed limit value can be used as the assignment source first, that is, the existing speed limit signs on the same road can be used to expand their coverage to cover the road sections lacking signs. For ordinary urban roads, when determining the marked speed limit for road sections lacking speed limit sign information, the derived speed limit value can be used as the assignment source first, that is, the derived speed limit value can be obtained by looking up a table based on the road type information. The specific assignment rules mentioned above will be discussed in the following text. Figures 3 to 6 The illustrated embodiment further illustrates this point.

[0050] The aforementioned priority setting rules are based on considerations such as the following: In highway or urban expressway scenarios, due to the lack of complex at-grade intersections, relatively simple topological structures, and singular speed limit rules, especially when driving along main roads, drivers tend to assume that speed limit signs apply to the entire road. Therefore, the principle of expanding coverage using actual speed limit values ​​is prioritized, which aligns with cognitive habits and reduces the overhead of speed limit labeling. In contrast, in ordinary urban areas, road intersections are dense and the environment is complex. The effective range of speed limit signs usually only applies to certain road sections. Therefore, the principle of using speed limit values ​​derived from road type information is prioritized to more accurately reflect regulatory requirements.

[0051] In other embodiments, priority rules may also be determined based on other factors, such as road scene complexity, intersection density, surrounding environment type, and historical speed limit data distribution characteristics.

[0052] Figure 3 This diagram illustrates the process of determining labeled speed limits for roads on a map in an exemplary scenario. This scenario corresponds to a highway or urban expressway. In this embodiment, the original effective range of existing speed limit signs on main road 3 is expanded, and labeled speed limits are determined for road segments lacking speed limit sign information based on the expanded effective range. The labeled speed limits for each road segment are identified by "SL" in the diagram.

[0053] exist Figure 3The image shows the main road 3 of the expressway, with a road classification of, for example, 0, consisting of three lanes, and the prescribed direction of travel is from right to left. The starting point of main road 3 is shown on the right side of the image. For ease of description, main road 3 is divided into sections D1 to D6. It can be seen that there are three speed limit signs 31, 32, and 33 on main road 3, with speed limits of 100 km / h, 80 km / h, and 120 km / h respectively. The original effective range of each speed limit sign is marked with double arrows in the image, that is, the section of road in which each sign is effective as recorded in the map data.

[0054] In the diagram, road segments D1, D3, and D5, not covered by the double arrows, are not within the effective range of any speed limit signs 31, 32, and 33, and thus fall under the previously defined category of "road segments lacking speed limit sign information." For these road segments D1, D3, and D5, in highway or urban expressway scenarios, the actual speed limits of existing speed limit signs 31, 32, and 33 on the main road 3 can be prioritized as the source for assigning the marked speed limit values. Therefore, the effective range of speed limit signs 31, 32, and 33 is first expanded to determine the expanded effective range of each sign. Then, based on the expanded effective range into which road segments D1, D3, and D5 fall, the actual speed limit value of the corresponding sign is used as its marked speed limit value.

[0055] Specifically, road segment D1 is located between the starting point of main road 3 and the first speed limit sign 31. The effective range of this first speed limit sign 31 is recorded in the map data as extending from the sign's location to the merging point of ramp R_A. Therefore, road segment D1 was originally not within the effective range of any speed limit sign. To address this, the effective range of the first speed limit sign 31 on main road 3 is extended forward to the starting point of that road, so that road segment D1 falls within the extended effective range of the sign. Thus, the actual speed limit value of sign 31, 100 km / h, can be used as the designated speed limit value for road segment D1.

[0056] From a driver's perspective, when entering a new highway 3, before seeing a clear speed limit sign 31, drivers typically expect the speed limit on that section D1 to be consistent with the first speed limit sign that appears thereafter. This extended rule aligns with both drivers' actual cognitive habits and the traffic regulations' requirement for continuity of speed limits on highways.

[0057] Section D2 is located within the effective range of the first speed limit sign 31 on the main road 3, so the speed limit value marked on it can be directly adopted from the actual speed limit value of the sign, which is 100km / h.

[0058] Section D3 is located after the end of the effective range of the first speed limit sign 31 on main road 3, and before the next speed limit sign 33 for non-tunnel sections. Therefore, the effective range of speed limit sign 31 is extended backward to the location of speed limit sign 33, so that section D3 falls within its extended effective range. Thus, the speed limit value marked on section D3 also adopts the actual speed limit value of speed limit sign 31, which is 100 km / h.

[0059] Section D4 is a tunnel or bridge section. A dedicated speed limit sign 32 is located at the beginning of this section. Its coverage area only covers the tunnel or bridge section itself and becomes invalid after exiting the tunnel or bridge. Therefore, the marked speed limit value for the entire tunnel or bridge section D4 is directly adopted from the actual speed limit value of sign 32, which is 80 km / h.

[0060] Section D5 is the section following the exit of tunnel or bridge section D4, where no new speed limit sign has yet appeared. Therefore, the effective range of the last speed limit sign 31 before entering tunnel or bridge section D4 is extended backward to cover section D5 after the tunnel exit, until the next speed limit sign 33 appears. Thus, section D5 falls within the extended effective range of speed limit sign 31, and its marked speed limit value is the actual speed limit of 100 km / h as indicated on that sign.

[0061] Section D6 is located within the effective range of the speed limit sign 33 that appears later on the main road 3, so the actual speed limit value of 120km / h on the sign can be directly used as its marked speed limit value.

[0062] In one embodiment (not shown), if a dedicated speed limit sign 32 is missing before tunnel or bridge section D4, the coverage area of ​​the last speed limit sign 31 before entering the tunnel or bridge section can be extended backward to cover tunnel or bridge section D4 and section D5 after its exit, until the next speed limit sign 33 appears. In this case, the speed limit value marked on section D4 adopts the actual speed limit value of 100 km / h from speed limit sign 31.

[0063] In an embodiment not shown, if no speed limit signs are installed on the entire main road 3, it is impossible to obtain the marked speed limit values ​​for each road segment by extending the scope of existing signs. In this case, the derived speed limit value that matches the road type information can be queried from Table 1 and used as the marked speed limit value for the main road 3.

[0064] Figure 4 This diagram illustrates the process of determining labeled speed limits for roads on a map in another exemplary scenario. This scenario corresponds to the highway or urban expressway level, combined with... Figure 4 The purpose is to illustrate how to determine the marked speed limit for ramp sections under this category.

[0065] exist Figure 4The diagram shows the main road 3 of the expressway and several ramps R_A to R_F connected to it. Among them, ramps R_A, R_B, and R_C are the entrance ramps of expressway 3.

[0066] For ramp R_A, there is a speed limit sign 35 at the starting point of the ramp, and the entire ramp is within the range of the sign 35. Therefore, the actual speed limit value of 40km / h specified by the sign 35 can be directly used as its marked speed limit value.

[0067] Ramp R_B is divided into sections D1 and D2. Section D1 is located before the first speed limit sign 34 appears, and is a section with missing speed limit sign information. The speed limit of 40 km / h can be derived from Table 1 based on the road type information and used as the marked speed limit. Section D2 is within the effective range of speed limit sign 34, therefore the actual speed limit of 60 km / h on sign 34 can be directly used as the marked speed limit.

[0068] Ramp R_C corresponds to the road formed after the merging of multiple ramps in a scenario where multiple ramps converge. It is formed by the merging of ramp R_B into ramp R_A, where R_A is the main ramp. Therefore, the speed limit of ramp R_C is the same as the speed limit of the main ramp R_A into which it merges, which is 40 km / h.

[0069] Ramps R_D, R_E, and R_F are exit ramps of Expressway 3.

[0070] Ramp R_D exits from the main road of the highway 3 and is located before the first speed limit sign 37 on the ramp. This ramp section R_D is considered to fall within the effective range of the dedicated speed limit sign 36 on the main road 3 for ramp R_D, therefore the actual speed limit value of 60km / h specified on sign 36 is used as its marked speed limit value.

[0071] Ramp R_E comprises the pre-branch and post-branch sections of the main ramp. For the pre-branch section, since it falls within the effective range of speed limit sign 37, the actual speed limit of 50 km / h on sign 37 can be directly used as the marked speed limit. For the post-branch section, the marked speed limit of the pre-branch section can be retained, also 50 km / h. Ramp R_F separates from the main ramp R_E, thus representing a branch ramp after the branch in the ramp bifurcation scenario. Since it does not have a speed limit sign, the deduced speed limit of 40 km / h, obtained from Table 1 based on road type information, is used as its marked speed limit.

[0072] Figure 5 This diagram illustrates the process of determining speed limits for roads on a map in another exemplary scenario. This scenario corresponds to road 4 in a typical city, which is a 5-level (urban arterial road) with two lanes and a right-to-left traffic direction. The right side of the diagram shows the starting point of road 4.

[0073] like Figure 5 As shown, the road is divided into several sections D1 to D9. Among them, sections D2, D4, D7, and D9 are within the effective range of speed limit signs 41, 42, 44, and 45, respectively. Therefore, the actual speed limit value of the corresponding sign can be directly used as its marked speed limit value.

[0074] For road sections D1, D3, D5, D6, and D8 that are not within the effective range of any speed limit signs, the handling method for this scenario differs from the standard approach. Figure 3 and Figure 4 The method for expanding the scope of speed limit signs prioritizes directly using the derived speed limit value determined based on road type information as the source of its value assignment.

[0075] Specifically, segment D1 is the starting segment of road 4, located before the first speed limit sign 41 appears on road 4. Based on its road classification of 5 and two lanes, the corresponding derived speed limit value of 60 km / h is obtained from Table 1 and is used as the marked speed limit value for segment D1.

[0076] Road segment D2 is immediately following the first speed limit sign 41. Since this sign does not explicitly state whether its area of ​​effect covers the entire road, its area of ​​effect needs to be reasonably limited in this scenario. For example, its endpoint could be set at the first intersection 51 that follows it. Road segment D2 falls within this area of ​​effect; therefore, the actual speed limit of 70 km / h on sign 41 is directly adopted as the marked speed limit.

[0077] Road segment D3 extends backward from intersection 51 and is located before the next speed limit sign 42, thus it is also a segment with missing speed limit sign information. Based on the road type information, the deduced speed limit value of 60 km / h is obtained from Table 1 and used as the marked speed limit value for road segment D3.

[0078] Section D4 is located between speed limit sign 42 and the subsequent end-of-speed-limit sign 43, and is within the effective range of sign 42. Therefore, the actual speed limit value of 30km / h on that sign is directly used as its marked speed limit value.

[0079] Road sections D5 and D6 are located after the end of speed limit sign 43, and are therefore considered to be outside the scope of speed limit sign 42 and not within the scope of any speed limit sign. They are therefore road sections with missing speed limit sign information. Based on the road type information, the deduced speed limit value of 60 km / h is obtained from Table 1 and is used as the marked speed limit value for road sections D5 and D6.

[0080] Section D7 is a tunnel section, and there is a dedicated speed limit sign 44 ahead of it. The scope of this sign covers the entire tunnel section. Therefore, the actual speed limit value of sign 44, 40km / h, is used as the marked speed limit value for section 7.

[0081] Section D8 is the section after the tunnel or bridge exit and before the next speed limit sign appears, which is a section with missing speed limit sign information. Based on the road classification of 5 and the two-lane attribute of its location, Road 4, the derived speed limit of 60 km / h is obtained from Table 1 and used as its marked speed limit.

[0082] Section D9 is located within the effective range of speed limit sign 45, so the actual speed limit of 50 km / h corresponding to sign 45 can be directly used as its marked speed limit.

[0083] Figure 6 This diagram illustrates the process of determining speed limits for map roads in another exemplary scenario. This scenario corresponds to road classifications within a typical city, where roads 9, 15, and 17 are bidirectional vectorized roads, meaning a single road link in the map data represents two opposite directions of traffic. Roads 5, 6, 7, and 8 are unidirectional vectorized roads, meaning a single road link in the map represents only one direction of traffic; bidirectional traffic would require two parallel road links in opposite directions.

[0084] These two vectorization methods follow similar logic for determining the marked speed limit value. The difference is that for unidirectional vectorized roads, it is usually only necessary to consider the speed limit sign set on one side of the road and determine its range of effect in combination with the direction of traffic; for bidirectional vectorized roads, it is necessary to consider the speed limit signs set on both sides of the road, and each sign is only effective for the direction of traffic corresponding to its side.

[0085] exist Figure 6 In the illustrated embodiment, when determining the speed limit value for road sections lacking speed limit sign information, the derived speed limit value is also preferentially used as the source of the assignment. For ease of description, all roads in the figure are now divided into road sections D1 to D11.

[0086] Road segments D1 to D3 are located on the horizontally extending, single-direction vectorized road 5 shown in the upper right of the diagram, with the designated travel direction being from right to left. Road segment D2 falls within the effective range of speed limit sign 51 (which extends to the next intersection), therefore, the actual speed limit of 70 km / h on sign 51 is directly used as the labeled speed limit for road segment D2. Road segments D1 and D3 both lack speed limit sign information, requiring the derivation of speed limits from a table based on road type information. For example, road 5 has a road classification of 5 and is a two-lane road; the derivation speed limit of 60 km / h is obtained from Table 1 and used as the labeled speed limit for road segments D1 and D3.

[0087] Sections D6 to D8 are located on the horizontally extending, single-direction vectorized road 6 shown in the lower right part of the diagram, with the designated traffic direction being left to right. Section D7 falls within the effective range of speed limit sign 61; therefore, the actual speed limit of 70 km / h on sign 61 is directly used as the marked speed limit for section D7. Sections D6 and D8 both lack speed limit sign information; therefore, based on road grade 5 and two-lane attributes, the deduced speed limit of 60 km / h is obtained from Table 1 and used as their marked speed limit.

[0088] Section D4 is located on a two-way vectorized road 9 extending horizontally. This entire road 9 lacks any speed limit signs, representing a complete absence of speed limit information. Based on its road type information (road grade 6, urban secondary arterial road, two lanes), the corresponding derived speed limit of 50 km / h is obtained from Table 1 and used as the marked speed limit for section D4.

[0089] Road segments D5 and D11 are located on longitudinally extending bidirectional vectorized roads 15 and 17, respectively, while road segments D9 and D10 are located on longitudinally extending unidirectional vectorized roads 7 and 8, respectively. None of these roads have speed limit signs; therefore, the derived speed limits must be determined by consulting tables based on their respective road type information. Specifically, roads 15 and 17, where segments D5 and D11 are located, have a road classification of 7, and the derived speed limit from Table 1 is 30 km / h. Road 7, where segment D9 is located, has a road classification of 5 and is a single lane, and the derived speed limit from Table 1 is 50 km / h. Road 8, where segment D10 is located, has a road classification of 5 and is a two-lane road, and the derived speed limit from Table 1 is 60 km / h.

[0090] It should be noted that the speed limit signs, speed limits, road grades, number of lanes, and derived speed limits involved in all embodiments of this application are illustrative and not intended to limit the scope of protection of this application. In practical applications, the values ​​of the above parameters and the configuration of rules can be adjusted according to the specific circumstances of traffic regulations, road design standards, and map data in different regions.

[0091] Figure 7 A schematic diagram of an apparatus for determining speed limit values ​​for map roads according to an exemplary embodiment of this application.

[0092] The device 10 includes a processor 11 and a memory 12, wherein the memory 12 may include a computer-readable storage medium such as a hard disk, RAM, or flash memory, and stores computer program instructions. The processor 11 may be a central processing unit (CPU), a microcontroller unit (MCU), a graphics processing unit (GPU), a neural network processing unit (NPU), a digital signal processor (DSP), or other general-purpose or special-purpose processor. When the processor 11 executes the computer program instructions in the memory 12, it can perform the method described above for determining and marking speed limits for roads on a map.

[0093] It should be noted that the specific process of determining and marking speed limits for roads on the map mentioned in this embodiment is only briefly described here. The relevant technical details have been fully explained in the foregoing method embodiments, and can be directly referred to in the description of the corresponding parts, and will not be repeated here.

[0094] Although specific embodiments of this application are described in detail herein, they are given for illustrative purposes only and should not be construed as limiting the scope of this application. Various substitutions, modifications, and alterations can be conceived without departing from the spirit and scope of this application.

Claims

1. A method for determining and marking speed limits for roads on a map, the method comprising the following steps: Obtain speed limit sign information for each road on the map, including the actual speed limit value and its effective range; Obtain road type information for each map road, and derive speed limit values ​​based on the road type information; as well as Based on the speed limit sign information and the road type information, a marked speed limit value is determined for each map road. In at least some cases, when determining the marked speed limit value for road segments where the speed limit sign information is missing, the source of the assignment is selected from the actual speed limit value and the derived speed limit value with different priorities.

2. The method according to claim 1, wherein, The selection of assignment sources from actual speed limits and derived speed limits, based on different priorities, includes: For highways or urban expressways, when determining the marked speed limit value for road sections lacking speed limit sign information, the actual speed limit value shall be used as the source of the value assignment. For ordinary urban roads, when determining the speed limit for road sections lacking speed limit sign information, the derived speed limit value should be used as the primary source for assignment.

3. The method according to claim 1 or 2, wherein, The method further includes: For road sections on the map that have speed limit signs, the actual speed limit value contained in the speed limit sign information is directly used as the marked speed limit value; and / or In cases where all road segments on the entire map lack speed limit signs, the derived speed limit values ​​are directly used as the marked speed limits for each road segment on the map.

4. The method according to any one of claims 1 to 3, wherein, The actual speed limit value will be used as the source for assigning values ​​to road sections lacking speed limit sign information in the following way: The scope of application of speed limit signs is expanded to determine the extended scope of application of speed limit signs; For road sections with missing speed limit sign information that fall within the extended coverage area, the actual speed limit value of the speed limit sign corresponding to the extended coverage area shall be used as the marked speed limit value.

5. The method according to claim 4, wherein, For highways or urban expressways, the scope of speed limit signs is expanded in the following ways: The effective range of the first speed limit sign on the main road is extended forward to the beginning of the main road itself; Extend the effective range of the previous speed limit sign on the main road to the location where the next speed limit sign appears; If a tunnel or bridge section on the main road lacks dedicated speed limit signs, the coverage area of ​​the last speed limit sign before entering that tunnel or bridge section will be extended backwards to cover that tunnel or bridge section and the section after its exit, until the next speed limit sign appears; and / or If there are dedicated speed limit signs on tunnels or bridges on the main road, the scope of the last speed limit sign before entering the tunnel or bridge will be extended backward to cover the section of road after the exit of the tunnel or bridge until the next speed limit sign appears.

6. The method according to any one of claims 1 to 5, wherein, For highways or urban expressways, the marked speed limits for ramps are determined using the following methods: In the scenario of entrance ramps, for the section of road before the first speed limit sign on the ramp, the derived speed limit value is used as the marked speed limit value; In the scenario of an exit ramp, for the section of road before the first speed limit sign on the ramp, the actual speed limit value of the dedicated speed limit sign for that ramp on the main road is used as the marked speed limit value; In the scenario of ramp bifurcation, the merged ramp adopts the speed limit value marked on the main ramp into which it was merged; and / or In the scenario of ramp bifurcation, the main ramp after the bifurcation uses the marked speed limit value of the ramp before the bifurcation, while the branch ramp after the bifurcation uses the derived speed limit value as the marked speed limit value.

7. The method according to any one of claims 1 to 6, wherein, For ordinary urban roads, the derived speed limit value should be used as the primary source of assignment in the following situations: -The section of road on the map before the first speed limit sign appears; -The section of road after the intersection and before the next speed limit sign appears; -The section of road after the speed limit sign is lifted and before the next speed limit sign appears; and / or -The section of road after the exit of a tunnel or bridge and before the next speed limit sign appears; For ordinary urban roads, the effective range of speed limit signs is limited in the following ways: - When a speed limit sign does not specify that its effective range is valid for the entire road on the map, the endpoint of the effective range of the speed limit sign is set to the location of the first intersection that appears thereafter.

8. The method according to any one of claims 1 to 7, wherein, The road type information includes: road grade, road link attribute, number of lanes, and road toll type. The speed limit is derived based on the road type information using the following method: Speed ​​limit tables are pre-configured and derived based on traffic regulations or road design standards; and Based on the road type information, the speed limit value that matches the road type information is queried from the preset derivation speed limit value table, and used as the derivation speed limit value.

9. An apparatus for determining marked speed limits for roads on a map, the apparatus comprising a memory and a processor, the memory storing computer program instructions, wherein when the computer program instructions are executed by the processor, the processor is capable of performing the method according to any one of claims 1 to 8.

10. A computer program product comprising computer program instructions, wherein, When executed by a processor, the computer program instructions enable the processor to perform the method according to any one of claims 1 to 8.

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