Network Transmission Of Images With Embedded Devices

With the development of the Internet and relevant technology, we have already entered the cybertimes. The netwrk has already permeated through all respects of our routine, life and study. Now, not only by PC can we surf the Internet, but also by various embedded equipments. In this thesis, we design one kind of special embedded equipments which can realize image information transmitting in the Internet.At present, embedded scheme that equipment surfs the Net are divided into three ways on the whole.(1) The chips of the microprocessor and special-purpose procotol inn, for instance the microprocessor interconnects with E1552, Webchip PS2000, etc. The major advantage of this kind of scheme is: The design engineer of application system needn't consider any protocols, and the order and data conveyed over can be realized connecting with the Internet network, which only need to be explained and carryed out by the network chip. The shortcoming is: Internet is always a technology of fat server and thin client therefore we must Expect relatively much to the capacity of the memory and the speed of operation, etc. A large number of 8/16 memory of processor exist limited in using, being very difficult in offering enough systematic resources.(2) Embedded network technology, the same as, Embedded Micro internetworking Technology (EMIT). EMIT adopts the desk-top computer or the high-performance embedded processor which is regarded as the gateway, called emGateway (the embedded network gateway). It supports TCP/IP protocols and operates HTTP service routine above, forms the server that a user can carry on the remote access through the network browser. The emGateway is connected with peripheral hardware that passes such lightweight buses as RS232, RS485, CAN, etc. The advantage of this scheme is: The complicated procotol is realized on the PC through emGateway, application system MCU only needs to deal with simpler emNet agreements, join the internet. The shortcoming is: Embedded equipment must surf the Net through PC or other high-performance processor.(3) The microprocessor and the Ethernet controled chip (Networ Interface Chip, NIC) realize the interface of the network. Here, 8/16 microprocessors can select many kinds of types to realize the procotol, select the different speed of microprocessors as the key chip according to the concrete demands,for instance, W78E58B, AT89C8252, SX52BD100 ,etc. Its advantage is: Surf the Net directly through embedded equipments. The shortcoming is: Expect memory capacity and operation speed to controller relatively high, so procotol software uses the simple TCP/IP protocl generally.This thesis has proposed one kind system that transmit image through network with embedded equipments. It is the third kind of Net surfing schemes adopted, namely make use of network card chip to realize the interface of the network. This system is divided into two major modules, such as, a module of dealing with video and a network interface, as Fig. 1 shows.This thesis adopts TMS320VC5509 as the embedded processor which not only finishs the information of the picture dealed with compression and storage, but controls the interface chip of network, and realize the embedded equipment surfing the Internet. The main research contents of this thesis include:(1) According to characteristic of control images, we propose a new compress algorithm which is based on the date storage afer sample, signal DPCM (difference pulse code ) , quantize, DCT, deposit in the size of the memory datum quantity of the frame, and change the frame rate and DCT transmitted and vary matrix Q in real time,.(2) Control interface chip RTL8019AS of network card with CPU of TMS320VC5509, through the coupling network voltage transformer, and connect with the paired line or the coaxial cable.This thesis is divided into 5 chapters: it has included the characteristic of the embedded system, the structure of the embedded equipment separately; introduced TMS320VC5509 and uC/OS-II embedded real-time operating system, realized uC/OS-II transplanting into TMS320VC5509; has explained the hardware circuit diagram of TMS320VC5509 and RTL8019AS interface, the disposition of RTL8019AS register, network card driver emphatically; has proposed a new compression algorithm according to the size of the data quantity after the collection and quantizing of the signal of the picture, change the algorithm turned into one yard of rates transmitting the frame rate and changing matrix in real time;Finally, we point out the weak point of this article and the further research direction, provide the research focal point of the follow-up work.