CN113179420B - City-level wide-area high-precision CIM scene server dynamic stream rendering technical method - Google Patents

Abstract

The invention discloses a dynamic stream rendering technical method for an urban wide-area high-precision CIM scene server, which is characterized by comprising the following steps of: the method comprises the following steps: the method comprises the following steps: scene visualization information data acquisition: s1: analyzing the recognition object; s2: slicing audio and video coding; step two: and (3) high-definition rendering dynamic stream output: s3: pushing flow; s4: pulling the flow; step two: transferring signaling service: s5: user signaling; s6: and transferring signaling. The method is reasonable in design, and aims at wide-area high-precision CIM scene rendering, visual elements and characteristic information are processed, space vector topological information is decomposed and extracted, a space vector database is established to support topological space analysis, so that the problem of distribution of urban wide-area high-precision CIM scene rendering is solved for users, and the technical support capability of high-precision, multi-device and cross-platform real-time operation and browsing of CIM scenes is provided.

Description

City-level wide-area high-precision CIM scene server dynamic stream rendering technical method

Technical Field

The invention relates to the technical field of CIM application platforms, in particular to a technical method for rendering dynamic streams of an urban wide-area high-precision CIM scene server.

Background

The high-precision CIM scene is an organic complex of a three-dimensional city space model and city information established on the basis of massive city information data, based on the fusion of BIM and GIS technologies, the CIM is used for accurately measuring the data granularity to a single module in a city building, and a cool special effect is added to manufacture a real-time dynamic, virtual-real interactive and intelligent city CIM scene; the communication signaling server side controls the program control exchange, the network database and other 'intelligent' nodes in the network to exchange the following related information: call setup, monitoring (supervisory), Teardown (Teardown), information required for distributed application processes (queries/responses between processes or user-to-user data), network management information. Signaling transmission establishes a message channel for a CIM scene and a visual stream server, and is used for ensuring a control signal required by normal communication; the highly visual stream service establishes a stable and reliable data transmission service with the signaling service through stream sockets, and the service ensures that data can be received in sequence without errors and repeated sending, and streams and distributes the collected signaling messages (see fig. 1 in the attached drawing of the specification).

In terms of spatial range and technical logic, the construction of cim (tyinformationcoding) is an organic combination of GIS data of a large scene, BIM data of a small scene and internet of things IOT. The existing BIM technology can realize digital twinning of component dimensions on each building in a city, so that the information of the building is digitalized; the GIS technology can be used for carrying out structured and time-lapse storage on intangible social and economic activity information in cities, such as topographic features, land utilization and other macro-space environmental features, crowd features, information fund flow and the like on the scale of the cities. The IOT technology can supplement the operation data of buildings in BIM and more importantly sense and collect the change of microcosmic environments in urban open spaces such as traffic flow, atmospheric hydrology and the like in real time through the wide arrangement of urban sensors. The BIM and the GIS are complementary in space range, the data structure is common, each building can be regarded as a ground feature in the GIS, and each city infrastructure such as pipelines, street lamps and the like can also be regarded as a member of the BIM. On the basis, the data of the Internet of things is embedded, the refinement degree of data space and time granularity is greatly improved, and fine, comprehensive, dynamic and real-time digitization of urban space is realized. On the basis of comprehensively collecting data, the CIM carries out structuring and standardized integration on data with different dimensions in each field through a unified data platform. On one hand, the urban data can be calculated, the spatial indexes such as building area and volume rate in any spatial range and the social and economic indexes such as population density, vehicle density and even water and electricity consumption can be statistically analyzed, and mining rules can be learned and simulated through a machine to predict. On the other hand, by means of a spatial information visualization technology, the city data can correspond to the spatial position of the city data in real time, and the city data is clear at a glance and is convenient for rapid perception and decision of operation and management personnel.

At present, after the CIM technology is applied to a smart city, a large-range, dynamic and real-time mass model data information is bound to be faced, and a common application mode has problems and challenges in a plurality of aspects such as large-quantity dynamic loading, browsing performance, object materialization, space topology analysis and the like:

loading mass model data: the file size of a single conventional building complete full-element model generally reaches 2G,1000 ten thousand triangular faces and 10 thousand components, the model is several times larger for a super high-rise complex building, in addition, a CIM platform is a system facing to an urban area level, the platform size covers hundreds to tens of thousands of building groups, the whole model data belongs to a mass level, and the traditional loading and application method inevitably encounters a bottleneck and difficulty;

the problem of loading high-precision model data is solved: in a conventional urban CIM scene, because the traditional scene rendering limitation scene adopts an LOD100 stage of an engineering BIM model structure in a large range. The model at this stage usually represents the building size, the analysis includes geometric information such as the volume, the building orientation, the wall surface, the solid size, the shape and the position of the model, the scene refinement degree is insufficient, and the professional structural analysis can not be reflected in the CIM scene;

for the browsing performance problem: because of the mass model data problem faced by the CIM platform, dynamic loading has bottlenecks and difficulties, the browsing performance of the scene is also affected, different from a client, a Web end firstly needs to solve network data transmission and consider the use limit of a front-end browser on resources, for example, the maximum limit of v8 of chrome on rendering on a 32-bit system for the use of a memory on a 32-bit system is 1G, the maximum limit on a 64-bit system is 4G, and the transmission needs to be determined according to the network conditions, most of the current large-scale Web3D applications have difficulty in achieving smooth access on the internet, this also becomes a similar pseudo-problem, in theory you can use the system anywhere you get to the internet, but in practice there are preconditions like: a first, sufficient bandwidth; second, the hardware support is good enough, the condition is obviously not easier than installing a plug-in or downloading an application, and the front end has a limit and cannot meet the loading of a high-volume high-precision CIM scene;

for the spatial topology analysis problem: in a city-level wide-area CIM scene, because the data of a refined BIM model cannot be loaded due to a bearing bottleneck, spatial topology analysis application such as collision analysis and connectivity analysis of an engineering construction pipeline cannot be carried out;

the problem of blocking rendered video stream: in the transmission process of general streams, videos are coded and decoded, high-definition videos often bring decoding pressure to hardware, and blockage caused by decoding is particularly obvious. If the hardware configuration of the mobile phone/computer is low or the version of the playing software is too low, the speed of encoding and decoding is reduced, and the video playing is possibly blocked;

the problem of video streaming that cannot be interacted with by users is as follows: the traditional streaming transmission mode is that multimedia files such as animation, video and audio and the like are divided into compression packets through a special compression mode, and the compressed streaming multimedia files such as the animation, the video and the audio and the like can be decompressed on a computer of a user by using a corresponding player or other hardware and software for playing and watching after the start delay of several seconds or dozens of seconds, the traditional streaming can not allow the user to have participation control right, and the BIM scene is reflected on human-computer interaction on one hand;

therefore, a technical method for rendering dynamic streams of a city-level wide-area high-precision CIM scene server is provided.

Disclosure of Invention

The invention aims to overcome the problems in the prior art and provides a dynamic flow rendering technical method for a city-level wide-area high-precision CIM scene server, aiming at the scene rendering of the wide-area high-precision CIM, visual elements and characteristic information are processed, space vector topological information is decomposed and extracted, and a space vector database is established to support topological space analysis, so that the problem of providing users with the distribution of the city wide-area high-precision CIM scene rendering is solved, and the technical support capability of operating and browsing the CIM scene in real time in a high-precision, multi-device and cross-platform manner is provided.

In order to achieve the technical purpose and achieve the technical effect, the invention is realized by the following technical scheme:

a dynamic stream rendering technical method for an urban wide-area high-precision CIM scene server comprises the following steps:

the method comprises the following steps: scene visualization information data acquisition:

s1: analyzing the recognition object;

s2: slicing audio and video coding;

step two: and (3) outputting the high-definition rendering dynamic stream:

s3: pushing flow;

s4: drawing the flow;

step two: transfer of signaling service:

s5: user signaling;

s6: and transferring signaling.

Preferably, in S1, the points, lines and planes in the field of view of the camera are collected by the correlation function under VC, and the resolution is changed, so that the whole image can be thought of as a large chessboard, and the resolution is expressed by the number of intersections of all the longitude lines and the latitude lines; under the condition of certain display resolution, the smaller the display screen is, the clearer the image is, otherwise, when the size of the display screen is fixed, the higher the display resolution is, the clearer the image is, visual information is identified through a scene lens, the resolution is set, and the image is loaded into a temporary cache in a slicing mode.

Preferably, in S2, compression techniques such as motion-compensated inter-frame prediction, DCT transformation, adaptive quantization, and entropy coding are performed on the analysis information data obtained in the first step.

Preferably, in S3, the collected audio/video data is encapsulated by using a transmission protocol, and is changed into streaming data; common streaming protocols include RTSP, RTMP, HLS, and the like, delay of using RTMP transmission is usually 1-3 seconds, and for a scene with a very high real-time requirement, such as mobile phone live broadcast, RTMP also becomes the most common streaming protocol in mobile phone live broadcast, and finally, audio/video streaming data is pushed to a network segment through a certain Qos algorithm and is distributed through CDN.

Preferably, in S4, the video stream is read from the visual stream server by using a corresponding protocol, and discrete cosine transform (DCT transform) is performed, and after the image is DCT-transformed, the main components of the frequency coefficients of the image are concentrated in a relatively small range and are mainly located in the low frequency part.

Preferably, in S5, the signaling transmitted between the user and the exchange office collects signal commands of receiving devices such as a keyboard, a mouse, and a touch screen of the user, and uses the signaling information transmitted by the D channel (16kbit/S) in a digital coding format.

Preferably, in S6, the signaling relay station transmits signaling between switching nodes in the communication network, i.e. network interface (NNI) signaling, which is transmitted on a trunk between signaling services by a user, and mainly controls the establishment and release of call-related commands and corresponding signaling communication connections in the communication network, and transmits communication-related information.

Compared with the prior art, the invention has the following beneficial effects:

the invention has reasonable design, the first: the technical goals of lightweight loading and efficient rendering of the city information model data are achieved by carrying out file format analysis on the CIM city information model data and carrying out decomposition and extraction on visual elements and characteristic information, cleaning the model data, hierarchical layering of the model, geometric expression optimization of the elements and reasonable combination of space elements;

secondly, the method comprises the following steps: the method comprises the steps of analyzing file formats of CIM city information model data, decomposing and extracting space vector topology information, vectorizing and mapping three-dimensional space elements, establishing a massive space vector information base, unitizing entity objects, establishing a space database space index, and providing quick retrieval and space topology analysis capabilities of city information model objects;

thirdly, the method comprises the following steps: the method comprises the steps of integrating BIM city information model data, geographic information GIS data and Internet of things IoT data information, integrating city underground and ground, indoor and outdoor and historical present situation future multi-dimensional information model data and city perception data, and constructing a high-precision CIM scene digital bottom board, so that CIM scene projection data information can be conveniently and fluidically pushed to signaling service through an encryption data packet.

Of course, it is not necessary for any product to practice the invention to achieve all of the above-described advantages at the same time.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a signal transmission flow chart among a CIM scenario, a visual stream server and a communication signaling server according to the present invention;

FIG. 2 is a first flowchart of a dynamic stream rendering technique method for an urban wide-area high-precision CIM scene server according to the present invention;

FIG. 3 is a flowchart II of a dynamic stream rendering technique method of an urban wide-area high-precision CIM scene server according to the present invention;

fig. 4 is a signal transmission flowchart of a scene streaming service according to the present invention;

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1-4, a technical method for rendering dynamic streams of an urban wide-area high-precision CIM scene server includes the following steps:

the method comprises the following steps: scene visualization information data acquisition:

s1: analyzing recognition objects

Collecting points, lines and planes in the visual field range of the camera by using a correlation function under VC, and changing the resolution, wherein the whole image can be imagined as a large chessboard, and the expression mode of the resolution is the number of intersections of all longitude lines and latitude lines; under the condition of certain display resolution, the smaller the display screen is, the clearer the image is, otherwise, when the size of the display screen is fixed, the clearer the image is, the higher the display resolution is, the visual information is identified through a scene lens, the resolution is set, and the image is loaded into a temporary cache in a slicing mode;

s2: sliced audio/video coding

Performing compression technologies such as interframe prediction, DCT (discrete cosine transform) transformation, adaptive quantization and entropy coding of motion compensation on the analysis information data obtained in the first step;

step two: and (3) high-definition rendering dynamic stream output:

s3: plug flow

Packaging the acquired audio and video data by using a transmission protocol to become streaming data; common streaming protocols include RTSP, RTMP, HLS and the like, the delay of RTMP transmission is usually 1-3 seconds, the RTMP also becomes the most common streaming protocol in mobile phone live broadcast for scenes with high real-time requirements, such as mobile phone live broadcast, and finally, audio and video streaming data is pushed to a network break through a certain Qos algorithm and is distributed through a CDN;

s4: pulling flow

Reading a video stream from a visual stream server by using a corresponding protocol, and performing Discrete Cosine Transform (DCT), wherein after the image is subjected to DCT, the main components of the frequency coefficient are concentrated in a smaller range and are mainly positioned in a low-frequency part;

step three: transfer of signaling service:

s5: user signaling

The signaling transmitted from the user to the exchange office collects the signal instructions of the receiving equipment such as a user keyboard, a mouse, a touch screen and the like, and adopts a D channel (16kbit/s) to transmit the signaling information by using a digital coding format;

s6: transfer signaling

Signalling that the signalling transfer station transfers between individual switching nodes in the communication network, i.e. network interface (NNI) signalling, it transfers on the trunk between signalling services for subscribers, and it mainly controls the set-up and release of call-related commands and corresponding signalling communication connections in the communication network, and transfers communication-related information.

The signaling service in the invention is composed of a source signaling point, a signaling point for receiving the message is a destination signaling point of the message;

there are three types of signaling points:

(1) a serviceswitching point (ssp) is a generation or termination point of signaling messages, essentially a local switching system (or switching center CO) that originates calls or receives incoming calls.

(2) SignalTransferPoint (STP) performs the function of a router, looks at messages sent by SSPs, and then switches each message to the appropriate place over the network. STP connects other signaling points and networks together to form larger networks.

(3) Servicecontrolpoint (SCP) is a typical access database server, and is a control center of an intelligent network service, and is responsible for executing service logic, providing a call processing function, receiving query information and a query database sent by SSP, sending a call processing instruction to the SSP after verification, receiving a ticket generated by the SSP, and performing corresponding processing.

One specific application of this embodiment is: the method is reasonable in design, and achieves the technical aims of lightweight loading and efficient rendering of the urban information model data by analyzing the file format of the CIM urban information model data, decomposing and extracting visual elements and characteristic information, cleaning model data, grading and layering the model, geometrically expressing and optimizing the elements and reasonably combining spatial elements;

the method comprises the steps of analyzing file formats of CIM city information model data, decomposing and extracting space vector topology information, vectorizing and mapping three-dimensional space elements, establishing a massive space vector information base, unitizing entity objects, establishing a space database space index, and providing quick retrieval and space topology analysis capabilities of city information model objects;

the method comprises the steps of integrating BIM city information model data, geographic information GIS data and Internet of things IoT data information, integrating multi-dimensional multi-scale information model data and city perception data of cities in the ground, underground, indoor and outdoor and historical current situations in the future, and constructing a high-precision CIM scene digital bottom plate, so that CIM scene projection data information is conveniently and fluidically pushed to signaling service through an encrypted data packet;

thus, for scene rendering of wide-area high-precision CIM, visual elements and characteristic information are processed, space vector topological information is decomposed and extracted, a space vector database is established to support topological space analysis, and an original wide-area high-precision CIM scene is converted into a set of technical scheme supporting fast and efficient rendering of stream media playing operation through three parallel technical routes of scene visual information data acquisition, high-definition rendering dynamic stream output and signaling service transfer, so that distribution of urban wide-area high-precision CIM scene rendering is provided for users, and the technical support capability of high-precision, multi-device and cross-platform real-time operation and browsing of the CIM scene is provided.

"HTTP" as referred to in the drawings of the present document is Hypertext transfer protocol (HTTP), a simple request-response protocol that typically operates on TCP;

"TCP" is Transmission control protocol (Transmission control protocol), a connection-oriented, reliable, byte-stream-based transport-layer communication protocol, defined by RFC793 of the IETF;

"Socket" is an abstraction of an endpoint for two-way communication between application processes on different hosts in a network. One socket is one end of process communication on the network, and provides a mechanism for the application layer process to exchange data by using a network protocol;

"SessionDescription": a message session description;

"offer sdp": a protocol for sending a session;

"AnswerSDP": a protocol of a response session;

"ICECandidate": candidate address events thrown by service messages.

In the description herein, references to the description of "one embodiment," "an example," "a specific example" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The preferred embodiments of the invention disclosed above are intended to be illustrative only. The preferred embodiments are not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims (1)

1. A technical method for rendering dynamic streams of an urban wide-area high-precision CIM scene server is characterized by comprising the following steps: the method comprises the following steps:

the method comprises the following steps: scene visualization information data acquisition:

s1: analyzing recognition objects

Collecting points, lines and planes in the visual field range of the camera by using a correlation function under VC, changing the resolution, imagining the whole image into a large chessboard, wherein the expression mode of the resolution is the number of intersections of all longitude lines and latitude lines; under the condition of certain display resolution, the smaller the display screen is, the clearer the image is, otherwise, when the size of the display screen is fixed, the clearer the image is, the visual information is identified through a scene lens, the resolution is set, and the image is loaded into a temporary cache in a slicing mode;

s2: sliced audio and video coding

Performing motion compensation inter-frame prediction, DCT transformation, adaptive quantization and entropy coding compression technology through the analysis information data obtained in the first step;

step two: and (3) high-definition rendering dynamic stream output:

s3: plug flow

Packaging the collected audio and video data by using a transmission protocol to obtain stream data; common streaming protocols include RTSP, RTMP and HLS, the transmission delay of RTMP is 1-3 seconds, the RTMP is used for live broadcast of a mobile phone in a scene with high real-time requirement, the RTMP also becomes the most common streaming protocol in live broadcast of the mobile phone, and audio and video streaming data are pushed to a network break through a Qos algorithm and are distributed through a CDN;

s4: pulling flow

Reading a video stream from a visual stream server by using a corresponding protocol, performing discrete cosine transform, and performing DCT (discrete cosine transform) on an image;

step three: transferring signaling service:

s5: user signaling

The signaling transmitted from the user to the exchange office collects the signal instructions of the keyboard, mouse and touch screen receiving equipment of the user, and adopts a D channel (16kbit/s) to transmit the signaling information by using a digital coding format;

s6: transfer signaling

Signalling transferred between switching nodes in a communications network by a signalling relay station, i.e. network interface (NNI) signalling, which is carried on trunks between signalling services by subscribers, controls the set-up and release of call-related commands and corresponding signalling traffic connections in the communications network, and conveys information relating to the traffic.

Images