Analysis of mobile ar implementation based on edge computing (Part 2)

0 Preface

        Move AR On the realization of , This article is mainly based on business , Design mobile according to business characteristics AR The implementation architecture of . Move AR The business is compute intensive , It involves a lot of data processing , Combined with the AR Terminal devices are usually portable and wearable products , The device is small and light , Therefore, the business part needs to be unloaded to the edge side or the cloud for processing . Based on the above principles , We divide the implementation framework into three layers , Namely AR terminal , Mobile edge and cloud . Each layer depends on the computing power , Energy consumption , Handle different businesses separately , Each layer cooperates with each other to complete the whole function . The detailed module design of each layer is shown in the figure below .

1 AR Terminal module

        AR The terminal is AR Carrier of business , It mainly completes the collection of environmental data and user posture , The transmission and final information are superimposed . In the figure above, this layer contains device connections 、 sensor 、 actuator 、 And equipment status 、 Security and networking related modules . The following is a description of the main functions of each module and the design challenges .

• Equipment connection mainly realizes AR Terminal network access and communication functions , Low power consumption should be considered in design , High bandwidth and low latency requirements .
• The sensor mainly completes the collection of environmental information and user interaction information , High precision is required 、 The real time , The quality of collected data will directly affect the subsequent data analysis .
• The actuator mainly superimposes the recognized data information or the generated 3D scene information onto the real environment seamlessly , It's like real existence , This requires high-definition display 、 Precise positioning 、 Real 3D scene rendering , Obviously AR It is difficult for the terminal to complete the above functions with its own resources , So under this framework ,AR The terminal is only responsible for completing the display .
• Equipment status reporting mainly focuses on AR Maintainability deployment of terminal equipment , Like most IOT devices ,AR After the terminal equipment is connected to the network , You need to report the status information of your own devices to the cloud or edge , To help you upgrade or solve some common fault information .
• Equipment safety is mainly aimed at AR Safe network access of terminal equipment , Authorized certification . because AR The terminal will recognize the user's posture , Sense users' intentions and preferences , Therefore, it is necessary to authorize such data .
• Edge nodes mainly refer to AR Networking between devices , Realize point-to-point direct communication and interaction .

2 AR Terminal system implementation

        As shown in the figure below is AR The basic devices required for the implementation of terminal equipment . around AR The terminal needs to collect environmental information and the user's posture , Various sensors are required . Such as camera , infrared , gyroscope ,GPS, Microphone , The headset , Touch chip, etc , These sensors are integrated into a pair of glasses or a car AR HUD On , Collect information about the real environment , In depth information , User attitude , gesture , Eyes , Voice etc. , Get the user's real intention , Interact with users .

        When a user is in an environment , The camera will capture the environment picture , Generally, two cameras are required , Plus infrared sensors , You can get the data information of the three-dimensional scene . The other side of the camera is facing the user , It mainly collects the focus information of users' eyeballs , The user's facial expression information , Provide the focus of data analysis users . Gyroscopes and GPS It is mainly used to generate user location information , Head movement information and angle , Predict in advance what users are interested in , The computing model can also be unloaded to the corresponding edge device in advance according to the user's location information , The details will be discussed in the next article . Microphones and earphones are mainly used to collect users' voice interaction information , The issuance of certain control instructions , It can interact through voice , Make identification more accurate . The ideal display mode is to display the interactive screen transparently , stay AR HUD On the device , Usually, the beam is projected , Either way, the virtual information should be seamlessly superimposed on the appropriate position of the real scene , For example, the navigation information is naturally displayed in the lane view range . As far as we are concerned AR Equipment view , On the vehicle terminal AR HUD Is most likely to develop rapidly , Compared with the on-board equipment in terms of resources AR Glasses are much richer , It can carry more computing tasks , comparison AR glasses , There is no demand for lightweight .

        The outermost part of the figure above refers to the adopted communication technology , because AR The terminal itself is low energy consumption , So after simply formatting the collected information , You need to unload them all to the mobile edge device for data processing . Even in car scenes , We also need to consider the optimization of energy consumption .

3 AR Terminal communication

        In terms of data transmission , If it is AR glasses , In terms of energy consumption , At present, only Bluetooth can be used to realize transmission , But there is very little data available for transmission , Unable to meet demand , If you use your mobile phone as an edge device , Can pass wifi Connect to your mobile phone , Unload some data to the mobile phone for processing , It can solve the problem of bandwidth , At present, this communication mode is the best choice . The future as 5G The evolution of chips and the reduction of communication energy consumption , Can be passed directly through 5G Way to connect , Completely satisfied AR High bandwidth requirements for data , But this requires the chip to be small enough in terms of size and energy consumption , It is difficult to achieve in a short time . Currently on board AR HUD Because it has rich space , Not affected by lightweight , You can choose LTE/5G Such cellular technology as a means of communication . If you will AR Glasses are used as the display terminal of vehicle , Use the on-board system as an edge computing device , That will AR With the car WIFI Connect , Can be realized AR Data access .

        The choice of communication technology should comprehensively consider the bandwidth , Time delay , As AR Terminal equipment , Do you want to uninstall , Where to uninstall , We should also make decisions according to the network quality and the number of users at that time , If the network quality is poor , Unloading will increase the delay , At this point, you should consider completing the calculation locally .

4 Summary

        This paper starts from AR From the perspective of the terminal AR Business and edge computing related implementation . The next article will focus on edge devices and the cloud AR Implementation related design , Coming soon .