Research And Application Of Acquisition And Transmission Technology For Sample Image By Electronic Probe

At present, our country faces the problem that the number of large-scale scientific instruments is insufficient, so the realization of remote network experiment of the large-scale scientific instrument is of great significance. When people use electronic probe to do experiment, the sample image information is one of the main parameter of the sample, so the study of electronic probe sample image collection and transmission technology is important to realize the remote sharing of electronic probe instrument, the realization of this system makes remote personnel participate in the on-the-spot experiment become possible, and it also offers reference for teaching of remote experiment at the same time.The research of remote sharing system for the large-scale instrument is still at preliminary stage in domestic and international at present. In foreign countries, the research of remote sharing system for the electron microscope instrument has been made great progress, but the picture compress algorithm adopted by the sharing system is such as JPEG in the sample image compression, there are still relatively few ones that adopted advanced code standards such as H.264,etc.. In 2005, The ion probe system, which is the national science and technology basic platform construction project and the demonstration of large-scale science equip remote sharing research, is developed successfully by the Beijing Ion Probe Center, China National Measuring Science Research Inst and Jilin University. However, the transmission of ion probe sample images is not by video but picture of the frame, so it affects the continuity of the sample images. For the electronic probe large-scale instrument, the continuous sample image video is very necessary for the understanding of the sample information, and also more vivid and intuitionistic for the remote participant; With the cooperation of voice communication, the remote staff can participate in the scene experiment from multidimension, so it make it close between the remote participant and laboratory; So it is necessary to develop a set of remote sharing systems which is suitable for the electronic probe instrument sample image. The study of sample image video capture and transmission technology is the focus of this article.Based on Visual C++6.0 development platform and the characteristic of the JXA-8200 electronic probe sample image, Adopting the module design concept, and according to the study of Directshow multimedia technology, COM component technology, multi-threaded technology, network communication technology, video capture and compression technology, this text designed and implemented the server and client software which based on C/S structure for the electronic probe image acquisition and transmission system.1.Server software(1) Sample image acquisition module On the basis of further research for JXA-8200 electronic probe sample image form and interface, adopting directshow multimedia technology, we enumerate video capturing source device and create a video source filter for the device, and realized the capturing of the sample image video data in the end.(2) Sample image coding moduleThe resolution of electron probe sample image video is generally much higher than the resolution of ordinary video, up to 1280 * 1024. The code for the sample image is critical under the situation that the current bandwidth of the internet is limited. On the basis of studying the popular video coding standard, This article make an effective compression for the sample image by the advanced X264 encoder which is an open-source encoder accord with the H.264 coding standard, it greatly reduces the rate of video image data and make it suitable to transmit In the current network.(3) Sample image sending moduleOn the basis of studying Socket network communication technology, the text designed and developed a send filter for the sample image by the TCP protocol, which realized the function of sending sample image video data through the network.2. Client software(1) Sample image receiving moduleLike the sender filter, the receiver filter was designed by the TCP protocol and realized the function of receiving sample image video data through the network(2) Sample image decoding moduleThe client program firstly enumerates the corresponding video decoder filter in the system,and then add it into the filter graph, it finally connect the filter's Pin with the front and behind filters'Pin and realized the function of decoding the sample image video data.(3) Sample image grabbing moduleThis module is realized by designing one grab filter, this filter is an transform filter, every Sample (a picture frame) flowing in Filter Graph will flow through this filter, so the filter need a custom interface to copy the video data from the Sample ,and save it to the local memory.Based on the research of electronic probe sample video image capturing, compression, transmission technology, this text design and realize the electronic probe sample image acquisition and transmission system, which solve a key technology for the large-scale scientific instrument network experiment. Meanwhile, the research of video capture and transmission technology can be used in fields such as the network classroom, teleeducation,etc.. Through experiment, the system is proved to be well functioning in LAN and campus network, and the real-time character of this system is good. but the performance is not good in the education network, it is needed to be improved in the future.