研究液晶光電相關濾波器於彩色影像之辨識

Recognition of color images by an electro-optical system constructed with liquid crystal device

余俊霖(Chun-Lin Yu)

指導教授 ： 陳祖龍

元智大學/工程學院/電機工程學系/碩士(2005年)

摘要

在本論文中，我們根據合成辨別函數法的概念提出一個新的方法，應用在聯合轉換相關器的彩色影像辨識系統中。此技術是將每一個彩色目標影像的三原色成分依比重個別處理，以各自設計出最佳化的三原色參考影像來辨識不同的目標，同時調整在頻域上的濾波器，使輸出平面的相關能量峰值能夠較為尖銳。此光學架構中所設計的理想濾波器函數，需由非線性方程式來解出。因此，我們設計一演算法來求解。以此演算法並不保證可求得一個收斂的解，但我們可以得到一個區域最佳的極值點。
本論文針對彩色目標影像之平面旋轉、雜訊、背景及形變等之辨識做研究。而在系統之效能評估方面，我們使用CPI、PSR等評估標準。由結果顯示我們所提出的方法及光學架構可以有效地辨識彩色影像。

關鍵字

相關器

並列摘要

In this thesis, according to the concept of the synthetic discriminant function (SDF), a novel technique is proposed to recognize color image displayed on the optical joint transform correlator. This technique separates the polychromatic target image into red, green and blue components. Furthermore, a weight for each training image is decided, and then a synthetic reference image for each channel is obtained. The purpose is to identify different target images. Besides, a filter in the frequency domain is utilized to make the correlation peaks sharper. The filter function is calculated from nonlinear equations. An iterative algorithm is designed to find a solution. Theoretically, this algorithm may not converge in some cases. However, a near optimum solution can always be found.
This thesis aims for image rotation, noise, background, and distortion recognition research. However, in the aspect of system evaluations, correlation peak intensity (CPI), peak to sidelobe ratio (PSR), and so on, are used as the standards. Simulating results show that the proposed novel technique and an optical architecture can recognize color images successfully.

並列關鍵字

Synthetic discriminant function ； Multi-channel non-zero order joint transform correlator

參考文獻

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[7] D. Casasent, W. T. Chang, “ Correlation synthetic discriminant Functions, ” Applied Optics, Vol.25, pp.2343-2350, 1986.