| As the concept of ’Healthy China’ has risen to a national strategy,telemedicine is experiencing a period of rapid development Specially,Remote eye care based on imaging applications has a unique advantage.The current remote ophthalmology and more remote reading mode-based remote transmission of static images,and doctors can not remotely operate ophthalmic instruments;part of the video transmission mode requires not only the development of complex streaming media servers and clients-ends,and costs of system deployment and later maintenance are high.In regard of these problems,this paper realizes an ophthalmic real-time inspection system that can remotely operate slit lamp microscope.The system uses B/S structure,the use of the browser as a client,no need to develop additional plug-ins.The doctor client and the remote nurse set up a P2P connection based on Google WebRTC technology through a Web browser,and the ophthalmologist can observe the video images collected by the ophthalmic electronic camera in real time.The system has the advantages of low development cost,low resource consumption and high platform compatibility,and provides a new way for the realization and popularization of remote ophthalmology.Based on the functional requirements analysis,the overall architecture design of the system is provided.Also,the main modules of slit lamp microscope,Web application and HID controller are designed and implemented respectively.What is worth mentioned is that the design scheme of slit lamp microscope terminal and HID controller are put forward,and the hardware circuit and software coding for these two parts are also given.In order to improve the response speed of the stepper motor on the slit lamp microscope terminal and reduce the loss step,it is necessary to select a reasonable stepping motor control algorithm.Based on the comparison of linear and S-type acceleration and deceleration curves,the dynamic model of stepper motor is established and analyzed,and the discrete mathematical model of S-curve is given.By verifying the correctness of the model through simulation and experiment,the vibration condition of the motor is tested.The experimental results show that the algorithm is superior to the linear curve algorithm in the acceleration or deceleration time and vibration performance.It turns out that the motor running effect satisfies the system demand.Three-tier Web application architecture based on SSH framework integration has been designed and implemented.On the basis of comparison of the common instant messaging scheme,the paper analyzes the principle mechanism of WebSocket protocol and designs and realizes the instant communication module.Moreover,the real-time video diagnosis analysis with the P2P connection is realized based on Google WebRTC technology from the aspect of media negotiation mechanism,signal bearer and NAT traversal.The design of the module is analyzed.The realization process of the signaling server is given,as well as the establishment of connection coding between the clients.We do the actual deployment and testing of the entire system,and it turns out that through the HID controller and the doctor client page controls to achieve the remote slit lamp microscope instrument control;based on WebRTC technology,the P2P connection between clients is successfully established and the patient’s real-time eye image is transmitted.The test results of Web applications show that all the applied cases are normally passed,.and the statistical analysis of the video transmission performance parameters shows that after WebRTC component is compressed by compiling under the guarantee of the image quality,the video diagnostic module has the characteristics of low resource consumption,low bandwidth requirements,low delay and so on. |
