Video Remote Control System Based on Labview

　　With the rapid development of science and technology, the Internet has entered thousands of households and has become an indispensable condition for life, work and study. Remote monitoring has gradually been applied to many fields such as government, education, medical care, production and public security.

　　In the construction of remote video measurement and control system, video acquisition is an essential module. Through video, the client can easily observe the situation on site at any time and issue control commands in real time. This article introduces the remote video monitoring system developed by virtual instrument LABVIEW software using control technology.

　　2. System hardware design

　　In the hardware system, the client PC uses TCP/IP communication to send control commands to the remote monitoring PC. The remote monitoring PC receives the control commands issued by the client PC and uses the data acquisition card to output control signals for operation.

　　2.1 Capture Card

　　The data acquisition card is a USB interface acquisition card launched by Haikaicong in February 2013. It has full D1 real-time monitoring/video playback, supports 720X576 high-definition resolution, 4-channel video input, and 4-channel audio input.

　　2.2 Control mechanism

　　In the control and operation mechanism, the analog output channel is used to control the main power switch , and the analog output voltage is connected to the relay to complete the control of the remote valve and switch.

　　3. System software

The data transmission scheme designed in this project mainly adopts TCP protocol, and uses Vision Acquisition Software　　in the visualization software LabVIEW to write a complete TCP usage control. In this design module, the main purpose is to transmit the image information collected by the server to the client, so the transmission part is the top priority. Because it uses TCP protocol, you can directly call the written TCP open, TCP write, TCP read and TCP close functions, and then make the corresponding connection.

　　3.1 Overall Block Diagram

　　The software is divided into two parts: server and client. LABVIEW software is needed to design an executable flow chart. The specific design is shown in Figure 1.

　　3.2 Video image display and acquisition module

　　In order to achieve the purpose of collecting experimental data while transmitting video, the video module and data acquisition module in the software design must be executed in parallel and independently. Two independent loop programs are set up in the LABVIEW software, which are controlled by different Boolean controls, so that video and experimental data can be collected at the same time. The image acquisition program block diagram is shown in Figure 2.

　　3.3 Video surveillance design

　　In the video surveillance module, the main task is to transmit the image information collected by the server to the client. Because the TCP protocol is used, the written TCP open, TCP write, TCP read and TCP close functions can be directly called, and then the corresponding connection can be made. The TCP/IP transmission part is a string, so the server needs to convert the collected image data into a string after the image is collected before it can be transmitted. At the same time, during the transmission process, once either the client or the server is interrupted, the entire communication process ends immediately, and a handler is provided for errors, as shown in Figure 3.

　　3.4 Video Saving Module Design

　　In modern remote video surveillance systems, image saving modules are indispensable. This can be achieved by using the picture writing file function control in LABVIEW, calling the WebcamFlatto picture.vi and Picture to Pixmap.vi functions, and then calling specific structure parameter settings and saving paths.

　　4. Summary

　　The use of image virtualization software LABVIEW makes the design of wireless video transmission system simpler and the human-computer interaction interface more intuitive and beautiful. Further design research can also be carried out on this system platform, such as image clarity setting, automatic saving, etc.