Detailed Description
Exemplary embodiments of the present disclosure are described below with reference to the accompanying drawings, in which various details of the embodiments of the disclosure are included to assist understanding, and which are to be considered as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the present disclosure. Also, descriptions of well-known functions and constructions are omitted in the following description for clarity and conciseness.
In practical applications, the road-level positioning can be simply divided into two stages, namely initialization and stable positioning. In the stable positioning stage, the road at the previous moment is determined, and even when the road is driven to the intersection at present, the selectable road is limited because the road which is not connected on the topological structure (such as a road network structure) at the previous moment is not considered. Therefore, stable prior information is obtained, and the selection range is narrowed. However, in the initialization phase, there is no a priori information and it is necessary to select the correct road from the roads within a certain radius around the current position of the vehicle with a very high accuracy. Based on this, this application scheme provides a road location scheme.
Specifically, the present disclosure provides a road positioning method, as shown in fig. 1, the method includes:
step S101: predicting to obtain position characteristic information of target vehicles at N adjacent moments, wherein the predicted position characteristic information represents a probability value of the target vehicles at the current moment in at least one associated candidate road; and N is an integer greater than or equal to 2.
Step S102: obtaining transfer characteristic information of the target vehicle from a time t to a time t +1 in the N moments based on the position characteristic information of the target vehicle at the N moments, wherein the transfer characteristic information at least represents a probability value of a transfer path corresponding to the target vehicle transferring from at least one candidate road associated with the time t to at least one candidate road associated with the time t + 1. Here, t and t +1 are two adjacent times within N times.
Step S103: and predicting the initial road of the target vehicle in the time period corresponding to the N moments from all the candidate roads based on the position characteristic information and the road transfer information.
Therefore, the initial road of the target vehicle is presumed based on the probability value of the candidate road associated with the target vehicle at the current moment and the probability value of the transfer path between two adjacent moments (namely, the moment t and the moment t + 1), so that the candidate roads and the transfer path are quantized from the perspective of the probability, and the initial road is selected, the problem of large error in the prior art is solved, the user experience is improved on the basis of realizing the road-level positioning, and the use scene is enriched.
In practical application, in the scene of automatic driving, the positioning precision of decimeter or even centimeter level is required. Before high-precision positioning is achieved, road-level positioning with extremely high accuracy is achieved. Obviously, the scheme of the application can be applied to an automatic driving scene, and provides support for realizing accurate road-level positioning of the automatic driving scene.
Here, it should be noted that the candidate road associated at time t may be the same as, may be different from, or may be only partially the same as the candidate road associated at time t + 1; based on this, the transition route may be a transition from the candidate road a at the time t to the candidate road B at the time t +1, or a transition from the candidate road a at the time t to the candidate road a at the time t +1, that is, the driving road does not change, which is not limited in the present application.
In a specific example of the application scheme, in order to further improve the accuracy of the initial road of the positioning, the application scheme may also be applied to a training scene, and at this time, the real initial road is known in advance, so as to further improve the accuracy of the positioning result. Specifically, based on the difference characteristics between the predicted initial road and the real initial road of the target vehicle in the time period corresponding to the N moments, the predicted position characteristic information is optimized.
In a specific example of the present application, the position feature information may be obtained by acquiring road image information of the target vehicle at the time t and geographic position information of the target vehicle; the road image information may be specifically a road on which the target vehicle is driving at the present time, and the information may be collected by a vehicle-mounted device, for example, a vehicle-mounted camera, and uploaded to a server for positioning processing. Further, predicting at least one candidate road associated with the target vehicle at the time t and a probability value of the target vehicle being in the associated candidate road based on the road image information and the geographic position information; and then, at least one candidate road associated with the target vehicle at the time t and the probability value of the target vehicle in the associated candidate road are used as the position characteristic information of the target vehicle at the time t, so that the position characteristic information of the target vehicle at each time of N times is obtained through prediction, and a foundation is laid for realizing road-level positioning subsequently.
In a specific example of the scheme of the application, a probability value of a candidate road associated at a certain time may also be obtained by determining at least two preset features required for locating a road where the target vehicle is located and initial weights of the preset features; here, the preset feature may be arbitrarily set based on an actual positioning requirement, and accordingly, the initial weight may also be arbitrarily set based on an actual requirement, which is not limited in the present application. Further, determining an initial characteristic value of the preset characteristic, wherein the initial characteristic value is determined based on the road image information of the target vehicle at the time t of the N times and the geographical position information; and then obtaining the probability value of the target vehicle at the time t in the associated candidate road based on the initial weight and the initial characteristic value, so as to obtain the position characteristic information of the time t in a prediction manner, and further obtain the position characteristic information of the target vehicle at each time in the adjacent N times in a prediction manner, thereby laying a foundation for realizing subsequent road-level positioning.
In a specific example of the scheme of the application, the optimizing the predicted location characteristic information specifically includes: optimizing the initial weight of the preset feature to obtain a target weight for the preset feature; wherein the initial road predicted based on the target weight matches the true initial road. Specifically, a probability value that the target vehicle is in the associated candidate road at the time t and a probability value that the target vehicle is in the associated candidate road at the time t +1 can be obtained based on the target weight, and then a probability value that the target vehicle transfers from the candidate road associated at the time t to the transfer path corresponding to the candidate road associated at the time t +1 is obtained, so that the initial road is obtained by prediction, and here, since the target weight is obtained by taking reference to the real road and optimizing and adjusting, the accuracy of the initial road obtained by prediction based on the target weight is higher, and further, the user experience is further improved.
In a specific example of the present application, the obtaining of the transfer characteristic information of the target vehicle from time t to time t +1 of the N times based on the location characteristic information of the target vehicle at the N times as described above may specifically include: acquiring the position characteristic information at the time t and the position characteristic information at the time t + 1; multiplying the probability value of the candidate road associated with the position characteristic information at the time t with the probability value of the candidate road associated with the position characteristic information at the time t + 1; and taking the multiplication processing result as transfer characteristic information of the target vehicle from the time t to the time t +1 in the N moments. That is, the result of the multiplication is used as the probability value of the transition path corresponding to the candidate road associated with the time t +1, for example, the probability value of the candidate road a associated with the time t is a1, the probability value of the candidate road B associated with the time t +1 is B1, and at this time, the probability value of the transition path is a1 multiplied by B1. Therefore, based on a simple quantification mode, transfer characteristic information from the time t to the time t +1 is obtained, and a foundation is laid for accurately determining the initial road.
In a specific example of the present disclosure, the predicting, based on the location characteristic information and the road transition information, an initial road on which the target vehicle is located in a time period corresponding to the N times from all the candidate roads may specifically include: obtaining probability values of all the transfer paths based on the position feature information and the road transfer information, for example, obtaining probability values of all the transfer paths based on a product relationship, and determining an initial road where the target vehicle is located based on a candidate road corresponding to the transfer path with the maximum probability value. That is to say, the transfer path with the maximum probability is selected as the driving path of the target vehicle, so as to predict the initial road, thereby realizing the road-level positioning, simultaneously improving the user experience and enriching the use scenes.
Here, it should be noted that, in the present application, the time t is any one of adjacent N times, in other words, in an actual application, the processing flow of the related information at any one of adjacent N times can be referred to the processing manner for time t in the above example, and details of each time are not repeated here.
Therefore, the initial road of the target vehicle is presumed based on the probability value of the candidate road associated with the target vehicle at the current moment and the probability value of the transfer path between two adjacent moments (namely, the moment t and the moment t + 1), so that the candidate roads and the transfer path are quantized from the perspective of the probability, and the initial road is selected, the problem of large error in the prior art is solved, the user experience is improved on the basis of realizing the road-level positioning, and the use scene is enriched.
The present disclosure will be described in further detail with reference to specific examples, and specifically, the road-level localization technology may utilize historical information and current information from an information perspective, and a hidden markov framework may well integrate information from two perspectives, based on which the present disclosure uses the hidden markov framework to achieve localization of an initial road, as shown in fig. 2, in which a state may also be referred to as state information and may be inferred based on observations (i.e., observation information), and thus may also be referred to as a hidden state. And the probability value of the transition road corresponding to the two adjacent states can be obtained based on the time sequence derivation. Specifically, the timing derivation and information matching are explained in detail:
first, timing derivation is performed to obtain the transition probability from the state derivation of the current frame to the state derivation of the next frame. Here, the frame may be understood as overall feature information including at least road image information and geographical position information for the target vehicle at the current time. In an actual scene, a real road is divided into a plurality of segments, each segment may be called a link and has its unique id, i.e. link id. Based on this, the state of the frame can be understood as a set of candidate road link ids where the target vehicle is likely to be located, which is presumed based on the observation (i.e., the global feature information) at the present time. Further, the timing derivation between adjacent states represents a probability, i.e., a transition probability, based on the map topology connectivity and the similarity between the variation of the previous and subsequent states and the variation of the previous and subsequent observations. For example, in the state T-1 and the state T in fig. 2, assuming that there are m possible link ids for the state T-1 and n possible link ids for the state T, a transition matrix T is obtained based on timing derivation, and the transition matrix T is a matrix of m × n. Further, after the probability values of m link ids in the state t-1 and the probability values of n link ids in the state t are determined, the probability value of the transition path related in the transition matrix, that is, the transition probability, can be obtained.
Secondly, information matching can be understood as a matching process of the overall characteristic information of the current frame and the map information, and can be characterized by a similarity probability, namely, the probability value of link id is characterized by the similarity probability. For example, the candidate road of the target vehicle at the current moment can be preliminarily screened out based on the relevant information of the GNSS, and then the attribute of the road where the positioning is located can be determined more accurately based on the acquired perception information and the like. For example, based on the road image information, it can be detected that the road where the target vehicle is currently located has three lanes, the lane line attributes are solid lines, dotted lines and solid lines, the colors are all white, and then the probability value can be given to the link id after the link id is matched with the map information.
In practical applications, there is no standard definition of the similarity probability. Based on the link id similarity calculation method, preset features such as the difference between the GNSS heading and the map heading, the vertical distance between the GNSS position and the map, the matching degree between perception information (such as information obtained through a vehicle-mounted sensor) and the map, the difference between the vehicle speed and the map road speed limit, the difference between the GNSS elevation and the map elevation and the like can be determined in advance to comprehensively calculate the link id similarity. Specifically, the preset features may be written as:
X=(x1,xx,...,xn)
assuming that each preset feature has independent distribution, converting the distribution into a probability value to represent, and obtaining:
P=(p1,p2,...,pn)
between the probabilities, a linear weighting form is adopted to obtain the similarity probability of a single link id:
note that the weight ω, whose magnitude represents the importance of the corresponding preset feature, can be trained to obtain the optimal weight combination through data-driven training.
Specifically, the optimal weight combination is obtained by training in a sliding window form, where if the window size is N, that is, N times are included, there are N observations inside the window, corresponding to N states. Based on this, the best value of each state, i.e. the best link id of each state, can be determined by means of determining the state chain (i.e. transition path) of the maximum probability inside the window. Here, it should be noted that, in the above process, the training is implemented by using the real road information as the reference information, so that the optimal weight combination is obtained.
Specifically, based on the similarity probability and the transition probability, the following formula is obtained:
(similar probability at time t) × (transition probability from time t to time t + 1) × (similar probability at time t + 1) × … × (similar probability at time t + N-1) × (transition probability from time t + N-1 to time t + N) × (similar probability at time t + N).
For each transition path (i.e., chain), the probability is a function of ω, and after the probability normalization processing of all chains, the proportion of the chain in all options can be seen, for example, the chain is characterized by means of a probability vector a.
Further, the above formula is also rewritten into the probability vector B by performing the labeling of the true value of the real scene, for example, when the probability of the road on which the target vehicle is located is 1 and the probability of the road to which the target vehicle does not travel is 0 in the real scene. In this case, the loss function may be the square of the difference between the normalized probability (probability vector a) and the true value (probability vector B). Thus, by a simple gradient descent method, the optimal omega parameter can be trained, so that the road selected by the multiplication of the probability expressed by omega is the road with the highest accuracy.
For example, as shown in fig. 3, suppose N is equal to 3, that is, 3 time instants are included in the sliding window, where the road associated withtime instant 1 includes a road a and a road D, and the probability value of the road a attime instant 1 is ρ1AThe probability value of the road D attime 1 is ρ1D(ii) a Similarly, the roads associated withtime 2 include road a, road B, and road C, and accordingly, the probability values are ρ2A,ρ2BAnd ρ2C(ii) a The roads associated with thetime 3 include a road B and a road D, and accordingly, the probability values are ρ3BAnd ρ3D. At this time, based on the scheme of the present application, the probabilities of all the links in the sliding window, that is, ρ (AAB) (the probability value representing the transition route corresponding to the road a fromtime 1 totime 2 and then to the road C from time 3), ρ (AAD), ρ (ABB), etc. may be obtained. Further, the p (aab) ═ ρ1A×TAA×ρ2A×TAB×ρ2BHere, T is as definedAAI.e. the probability value of the transition route corresponding to the road a fromtime 1 totime 2, for example, equal ρ1A×ρ2A. Thus, the chain with the maximum probability is determined, and the initial road is obtained.
In conclusion, the scheme of the application emphasizes the problem of initialization of the hidden Markov model based on the sliding window, and compared with the current situation that the initialization stage is lack of discussion and realization in the traditional technology, the scheme of the application makes a complete abstraction on the initialization technology, makes full use of the related information of multiple sensors of the target vehicle, simplifies the initialization into the classification model problem, and further obtains the initial road with higher accuracy. At present, the accuracy rate of the test data of 1w kilometer in the scheme of the application can basically reach more than 99.9%.
This application scheme still provides a road positioner, as shown in fig. 4, the device includes:
the prediction unit 401 is configured to predict and obtain location feature information of target vehicles at N adjacent moments, where the predicted location feature information represents a probability value that the target vehicle is located in at least one associated candidate road at a current moment; n is an integer greater than or equal to 2;
a transfer characteristic determining unit 402, configured to obtain transfer characteristic information of the target vehicle from a time t to a time t +1 of the N times based on the location characteristic information of the target vehicle at the N times, where the transfer characteristic information at least represents a probability value of a transfer path corresponding to the transfer of the target vehicle from at least one candidate road associated with the time t to at least one candidate road associated with thetime t + 1;
an initial road determining unit 403, configured to predict, based on the location characteristic information and the road diversion information, an initial road on which the target vehicle is located in a time period corresponding to the N times from all the candidate roads.
In a specific example of the scheme of the present application, the method further includes:
and the optimization unit is used for optimizing the predicted position characteristic information based on the predicted difference characteristics between the initial road and the real initial road of the target vehicle in the time period corresponding to the N moments.
In a specific example of the application, the prediction unit is further configured to obtain road image information and geographical location information of the target vehicle at the time t; predicting at least one candidate road associated with the target vehicle at the time t and a probability value of the target vehicle in the associated candidate road based on the road image information and the geographic position information; and taking at least one candidate road associated with the target vehicle at the time t and the probability value of the target vehicle at the associated candidate road as the position characteristic information of the target vehicle at the time t so as to predict the position characteristic information of the target vehicle at N times.
In a specific example of the application, the prediction unit is further configured to determine at least two preset features required for locating the road where the target vehicle is located, and initial weights of the preset features; determining an initial characteristic value of the preset characteristic, wherein the initial characteristic value is determined based on road image information of the target vehicle at the time t of the N times and geographical position information of the target vehicle; and obtaining a probability value of the target vehicle at the associated candidate road at the time t based on the initial weight and the initial characteristic value so as to predict and obtain the position characteristic information at the time t.
In a specific example of the solution of the present application, the optimizing unit is further configured to optimize an initial weight of the preset feature to obtain a target weight for the preset feature; wherein the initial road predicted based on the target weight matches the true initial road.
In a specific example of the scheme of the application, the transfer characteristic determining unit is further configured to obtain the position characteristic information at the time t and the position characteristic information at thetime t + 1; multiplying the probability value of the candidate road associated with the position characteristic information at the time t with the probability value of the candidate road associated with the position characteristic information at thetime t + 1; and taking the multiplication processing result as transfer characteristic information of the target vehicle from the time t to the time t +1 in the N moments.
In a specific example of the scheme of the application, the initial road determining unit is further configured to obtain probability values of all transition paths based on the location characteristic information and the road transition information; and determining an initial road where the target vehicle is located based on the candidate road corresponding to the transfer path with the maximum probability value.
The functions of each unit in the road positioning device according to the embodiment of the present invention may refer to the corresponding description in the above method, and are not described herein again.
The present disclosure also provides an electronic device, a readable storage medium, and a computer program product according to embodiments of the present disclosure.
FIG. 5 illustrates a schematic block diagram of an exampleelectronic device 500 that can be used to implement embodiments of the present disclosure. Electronic devices are intended to represent various forms of digital computers, such as laptops, desktops, workstations, personal digital assistants, servers, blade servers, mainframes, and other appropriate computers. The electronic device may also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions, are meant to be examples only, and are not meant to limit implementations of the disclosure described and/or claimed herein.
As shown in fig. 5, theelectronic device 500 includes acomputing unit 501, which can perform various appropriate actions and processes according to a computer program stored in a Read Only Memory (ROM)502 or a computer program loaded from astorage unit 508 into a Random Access Memory (RAM) 503. In theRAM 503, various programs and data required for the operation of theelectronic apparatus 500 can also be stored. Thecalculation unit 501, theROM 502, and theRAM 503 are connected to each other by abus 504. An input/output (I/O)interface 505 is also connected tobus 504.
A number of components in theelectronic device 500 are connected to the I/O interface 505, including: aninput unit 506 such as a keyboard, a mouse, or the like; anoutput unit 507 such as various types of displays, speakers, and the like; astorage unit 508, such as a magnetic disk, optical disk, or the like; and acommunication unit 509 such as a network card, modem, wireless communication transceiver, etc. Thecommunication unit 509 allows theelectronic device 500 to exchange information/data with other devices through a computer network such as the internet and/or various telecommunication networks.
Thecomputing unit 501 may be a variety of general-purpose and/or special-purpose processing components having processing and computing capabilities. Some examples of thecomputing unit 501 include, but are not limited to, a Central Processing Unit (CPU), a Graphics Processing Unit (GPU), various dedicated Artificial Intelligence (AI) computing chips, various computing units running machine learning model algorithms, a Digital Signal Processor (DSP), and any suitable processor, controller, microcontroller, and so forth. Thecalculation unit 501 performs the respective methods and processes described above, such as a road positioning method. For example, in some embodiments, the road location method may be implemented as a computer software program tangibly embodied in a machine-readable medium, such asstorage unit 508. In some embodiments, part or all of the computer program may be loaded and/or installed onto theelectronic device 500 via theROM 502 and/or thecommunication unit 509. When the computer program is loaded into theRAM 503 and executed by thecomputing unit 501, one or more steps of the road locating method described above may be performed. Alternatively, in other embodiments, thecomputing unit 501 may be configured to perform the road location method in any other suitable manner (e.g., by means of firmware).
Various implementations of the systems and techniques described here above may be implemented in digital electronic circuitry, integrated circuitry, Field Programmable Gate Arrays (FPGAs), Application Specific Integrated Circuits (ASICs), Application Specific Standard Products (ASSPs), system on a chip (SOCs), load programmable logic devices (CPLDs), computer hardware, firmware, software, and/or combinations thereof. These various embodiments may include: implemented in one or more computer programs that are executable and/or interpretable on a programmable system including at least one programmable processor, which may be special or general purpose, receiving data and instructions from, and transmitting data and instructions to, a storage system, at least one input device, and at least one output device.
Program code for implementing the methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the processor or controller, cause the functions/operations specified in the flowchart and/or block diagram to be performed. The program code may execute entirely on the machine, partly on the machine, as a stand-alone software package partly on the machine and partly on a remote machine or entirely on the remote machine or server.
In the context of this disclosure, a machine-readable medium may be a tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. The machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of a machine-readable storage medium would include an electrical connection based on one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.
To provide for interaction with a user, the systems and techniques described here can be implemented on a computer having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to a user; and a keyboard and a pointing device (e.g., a mouse or a trackball) by which a user can provide input to the computer. Other kinds of devices may also be used to provide for interaction with a user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user may be received in any form, including acoustic input, speech input, or tactile input.
The systems and techniques described here can be implemented in a computing system that includes a back-end component (e.g., as a data server), or that includes a middleware component (e.g., an application server), or that includes a front-end component (e.g., a user computer having a graphical user interface or a web browser through which a user can interact with an implementation of the systems and techniques described here), or any combination of such back-end, middleware, or front-end components. The components of the system can be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: local Area Networks (LANs), Wide Area Networks (WANs), and the Internet.
The computer system may include clients and servers. A client and server are generally remote from each other and typically interact through a communication network. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other.
It should be understood that various forms of the flows shown above may be used, with steps reordered, added, or deleted. For example, the steps described in the present disclosure may be executed in parallel or sequentially or in different orders, and are not limited herein as long as the desired results of the technical solutions disclosed in the present disclosure can be achieved.
The above detailed description should not be construed as limiting the scope of the disclosure. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions may be made in accordance with design requirements and other factors. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present disclosure should be included in the scope of protection of the present disclosure.