Design And Implementation Of Handheld Terminal Display System Based On DM365

Handheld terminal plays an important role in the current construction of "Intelligent Highway". To meet the demand of real-time video recording in emergency cases, this dissertation, based on new platform, focuses on the research and development of the handheld terminal display system, which includes graphic interface and video capabilities, hoping it can provide reference values for the promotion of handheld terminals in various fields like transportation and urban construction. The main work and accomplishments of this dissertation includes:1. According to the needs in both control and computation aspects and through comparisons among common schemes in the design of handheld terminals, this dissertation nails down the use of Davinci technology and DM365processor as the platform selection. Based on DM365, the dissertation designs the hardware and software hierarchy of the handheld terminal, and selects Qt as its graphic interface software through comparison.2. In terms of design and implementation of the graphic interface, the dissertation first introduces the Qt environment and its development process. Then based on the signal and slot mechanism, Qt windows and their switch among each other are designed; and the communications between the graphic interface and other processes are resolved through the message queue method.3. In video design, due to the necessary interactions among video capture, display and encoding, a multi-thread idea is put forward; to solve the synchronization among the threads, video data transportation synchronization based on the pipeline and initialization synchronization based on mutex and conditional variable and are presented; in single thread design, the capture and display thread are realized based on V4L2and DMAI, while the encoding thread is completed through calls of video co-processor by the Codec Engine software module.4. Considering the resolution differences between the video captured and the video to be displayed on the LCD, the dissertation compares and analyzes several common video interpolation scaling algorithm through MATLAB simulation, and then in order to get both good quality and low computation, an improved interpolation video scaling algorithm by combination of the existed bilinear and bi-cubic interpolation algorithm is put forward.