Design Of Automobile Electronic Rearview

Generally speaking, drivers observe the status after the vehicle through traditional rearview mirror in the process of reserving the car. However, invisible corner, blurred and inaccurate vision may happen in this observation as well as some other situations just like this, which often lead to the fact that the drivers cannot reverse their cars safely. In order to make up the disadvantages of the traditional rearview mirror, this thesis designed a kind of automotive electronic rear-view mirror.The automotive electronic rear-view mirror system designed by this thesis is made up of five subsystems:ultrasonic distance measuring subsystem, rear-view camera subsystem, control subsystem, display subsystem and the voice alarming subsystem. This system has applied the ultrasonic distance measuring technology and the rear-view camera technology, and added the functions of HD video display and accurate voice alarming. In this way, the drivers do not need to turn their heads, but can see the scene after the vehicle clearly and know the accurate distance between the car and obstacles through the multi-function display installed in the automobile driving cab so that drivers can reverse their cars more safely.In this thesis, the background and the significance of the research topic were firstly introduced, and then the author analyzed the current research situation in this field in both domestic and foreign countries, and based on these, the author put forward the systematic overall design philosophy as well as its realization scheme and described the function of each subsystem.Besides, the thesis presented more than one realization scheme for each subsystem of the automotive electronic rear-view mirror system, chose the best one through comprehensive consideration based on the analysis and comparison of advantages as well as disadvantages of each scheme, and finally confirmed the structure of each subsystem. The author carefully designed the hardware circuit employed in this system, mainly consisting of ultrasonic transmitting and receiving circuit, control circuit, video decoding circuit, image processing circuit, coding circuit and alarming circuit, etc. and drew up some hardware circuit diagrams. Control of transmitting and receiving signal in the ultrasonic distance measuring circuits was realized by means of MCU; processing of the video image in the rear-view camera subsystem was done with DSP; the voice alarming subsystem was completed by adopting the IC and buzzer; and LCD was adopted to display the rear-view scene.At last, the author designed the software program of the automotive electronic rear-view mirror system according to the hardware circuits in this system, drew the software flow chart and edited the program. In the ultrasonic distance measuring subsystem,40kHz pulsating wave was produced by way of MCU software, which can control the transmitting and receiving of ultrasonic wave. In the rear-view camera subsystem, software was designed to propel the camera to control the collection of video image and the storage of image data; image processing algorithm was employed to process image. In the voice alarming subsystem, distance measurement subprogram was adopted to measure the real-time distance, according to which corresponding voice alarming was chosen.