建構嵌入式車牌辨識系統

Constructing Embedded Car License Plate Recognition System

陳奕志(I-Chih Chen)

指導教授 ： 洪文斌

淡江大學/工學院/資訊工程學系碩士班/碩士(2005年)

https://doi.org/10.6846/TKU.2005.00405

摘要

嵌入式系統乃是為特定目的製作的計算平台，由於工作較為專一，不似個人電腦以泛用型計算平台為目的，所以硬體架構精簡，生產成本低廉、耗電量低、體積小、可作為移動計算的平台。但受限於其精簡的架構，處理器運算速度慢。本篇論文以車牌辨識系統為例提出一套移植軟體到嵌入式系統下的方法，並針對嵌入式系統的特性作效能上的改進。將車牌辨識中影像前處理步驟常用的演算法改用位移算子和整數運算，避免使用浮點數運算以提升系統效能。另外，影像擷取裝置CMOS 所擷取到的影像格式為Color Filter Array，會損失掉原本的光線強度的三分之二，對其進行光線補正動作時原本會進行大量的浮點運算，但使用上述加速的方法後可減少數倍的計算時間，在移植的開發板上使用uClinux輔助硬體間的溝通與程序的排程，讓嵌入式系統能執行較複雜的程序操作，並讓軟體移植更為順暢。開發期間應用Network File System(NFS)不但解決開發期間儲存空間不足的問題，並且能減少除錯期間反覆燒錄韌體的次數。除錯期間利用TCP/IP傳遞影像至遠端電腦辨識，雙方的結果互相比對可測試移植的正確性。

關鍵字

嵌入式系統 ； 車牌辨識

並列摘要

Embedded System is a computing platform designed for specific purpose. Because it’s task is much simpler than personal computer which is designed for general computing purpose, Embedded System can simplify its hardware architecture, cost down its hardware price, produce smaller device and low energy consumption. It also fits to be mobile computing platform. But Embedded System is constrained by its simple architecture; its processing power is much slower than personal computer.
This paper purpose a software porting procedure between personal computer and Embedded System platform via a instance of Car License Plate Recognition System , and make Embedded Car License Plate Recognition System more efficient via exchange floating operation by integer operation and bitwise operation. For Example the image format captured by COMS, is Color Filter Array ,and this format will lost 2/3’s original image illumination. The illumination recovery process was originally involve with mass of floating operation, after applying the speeding method that we just mention before the processing time become times faster.
We also use uClinux to assist hardware communication and process scheduling, and uClinux makes Embedded System able to handle complicated process control, also make software porting much smooth. Network File System ,NFS not only resolving the problem of lacking storage media, but also reduces the times of flash Rom burning procedure. Finally we use TCP/IP to transfer the image captured by CMOS to remote personal computer for Car License Plate Recognition ,and compare Car License Plate Recognition results between Embedded System and personal computer.

並列關鍵字

Embedded System ； Car License Plate Recognition

參考文獻

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