臺灣博碩士論文加值系統

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。

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.

第一章 緒論 1
1.1 引言 1
1.2 研究動機 1
1.3 論文架構 2
第二章 影像處理技術 3
2.1 空間領域的影像和像素鄰居表示方法 3
2.2 長條圖 Histogram 4
2.3 邊緣強化與Sobel濾波器 5
2.4 灰階值延展Gray Level Stretching 7
2.5 K mean 二值化 8
第三章 車牌辨識技術 10
3.1影像擷取與Color Filter Array 10
3.2車牌定位 12
3.3字元切割 14
3.4字元辨識 16
3.5特徵正規化 16
3.6 類神經網路架構 17
第四章 嵌入式系統與實作 21
4.1嵌入式系統簡介 21
4.2 Embedded Linux 22
4.3 uCLinux簡介 22
4.4 使用uClinux的優點 24
4.5 NTFS Network File System 24
4.6 ARM７處理器簡介 25
4.7 嵌入式系統的開發環境 26
4.7.1 嵌入式系統開發板Creator 26
4.7.2 軟體套件 28
4.7.3 程式編譯與執行流程 29
4.7.4 安裝Cygwin 30
4.7.5 安裝Arm-tool-chain 31
4.7.6 編譯uClinux核心以支援NFS 31
4.7.7 在PC端的cygwin啟動NFS分享 35
4.7.8 啟動NFS 35
4.7.9 安裝Creator的cmos╲lcd驅動程式 36
4.7.10燒錄映像檔 41
4.8 Makefile簡介 44
4.9 使用Domingo開發程式 45
4.10 程式移植過程 49
4.10.1 程式架構簡介 50
4.10.3 後端程式簡介 52
4.10.4 測試方法 52
4.11實驗結果 56
第五章 結論與待改進方向 58
結論 58
待改進方向 58
參考文獻 60

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