For The Design Of The Dsp System For Real-time License Plate Recognition

With the development of transportation system,more and more roads are constructed and more and more vehicles are used,there are more and more demands on the management of transportation system,Intelligent Transport System(ITS) provides a scientific method for it. License Plate Recognition(LPR) is the key of ITS. With the development of LPR technology,LPR is widely used in toll station,parking lot traffic management,automatic payment of highway toll fee,and so on.LPR is a very hard research area. The license plate automatic recognition systems of now-days still have some shortage:It is too expensive,the recognition speed is not fast enough,and the ratio of recognition is not high enough. After all,because the whole LPR system is based on PC software it is hard to protect the right of the LPR system.Digital Signal Processors(DSP)are the powerful tools for digital signal processing. It is widely used in digital communication,signal processing,industry controlling and so on.LPR is an important research area of our laboratory. In order to control the cost of the LRP system,improve its performance and protect the right,based on analysis the characters of the algorithm of LPR and the characters of DSP chips and DSP systems,We draw a conclusion,that the LPR system based on DSP can resolve those shortage.We have developed two LPR systems based on DSP:one is a general DSP signal processing system based on PCI bus. The other is a special License Plate recognition system based on DSP. Though the research,I get the knowledge of the structure of the DSP,the knowledge of DSP system development flow. Designed and made a general DSP signal processing system based on PCI bus,and write the driver of this system,and at the end,I validate the function of the system through FFT. During design the special License Plate recognition system based on DSP,I resolved many problems such as video capture synchronization,the conversion from 16 bits RGB to 24 bits RGB,the interface between DSP and SDRAM,FLASH video capture and host PC and so on. This paper gives a detail introduction about these two systems.In chapter two,I analysis the characters of the algorithm of LPR andthe characters of DSP chips and DSP systems. We draw a conclusion,that the LPR system realization though DSP have some advantages. In chapter three,I introduce the flow chart of DSP system development,tools of DSP development and eXpressDSP Algorithm Standard. In chapter four,I designed a general DSP signal processing system based on PCI bus. In this chapter,I introduce the hardware design of this system,include:PCI interface,memory expand and the communication between the DSP and the host PC. In chapter five,I introduce the design of the software of the general DSP signal processing system based on PCI bus. Include BOOTLOAD and PCI driver. In chapter six,I designed a special LPR system based on DSP.I introduce the interface and the drivers of DMA and PCI bus. In chapter sever,I conclude the work what I had done and analysis the work still need to been.