Image Technology Research In Automotive GPS Equipment

GPS technology has been widely used in the field of taxi and current of materials. At the same time customers want to get more functions in GPS equipments, image capture is a important need of them, and customers also want the cost of solution should be low. After market research, we found that the camera with usb interface has been widely used in pc, so this paper introduces a low cost solution with ARM9+WinCE+camera with usb interface. This paper gives a detailed introduction of development process including hardware and software. Main topics are as follows.1.Hardware development of new generation GPS equipmentThis part of the paper introduces the design process, features of CPU, functions of each part and electrical characteristics of key components. Operation system: WinCE.net is also introduced in this part.2.Usb protocolBasic theories of USB1.1 including topology of usb bus, structure of TokenPachet, transport type and bus Enumeration are introduced in this part. Usb interface of CPU is also described.3.JPEG/MJPEG coding alorithmCoding alorithm of JPEG is introduced, and detailed information of jpeg data is given with a sample of JPEG picture. At the end of this part the stream head of MJPEG is described.4.Development of usb driverThis part of the paper introduces choise of camera, loding process of usb driver and describes the structure of driver, definition of ioctl command and structure of code.At the end of the paper some tests are done and some useful conclusion are derived.