臺灣博碩士論文加值系統

在人們對於影像品質越來越重視的今天，影像的柔化日趨受到重視，但是在高品質的背後是所費不貲的，如何得到便宜品質又好的影像是本文研究的重點。
為解決此一問題，本論文提出理用薄膜的製程製作相位式的光柵可以當作光學低通率波器，置於CCD（Charge Couple Device）前，可以消除偽訊號等高頻雜訊，使影像趨於逼真，以解決因為使用晶體當作低通率波器產生不利於系統縮小化及成本昂貴的問題。

A new method utilizing the technique of coating process was applied to make a grating optical low-pass filter (GOLF). Using a metal mesh as a mask, the thin-film phase grating was fabricated with an advantage of simple and process for a mass-production. The modulation transfer function (MTF) was measured and proved it was agree well with the theoretical calculation. The GOLF was installed to a digital camera to take pictures of the circular zone plane (CZP) to show the ability of suppression of a Moiré pattern.

摘要……………………………………………………………………Ⅰ
Abstract………………………………………………………………Ⅱ
誌謝……………………………………………………………………Ⅲ
目錄……………………………………………………………………Ⅳ
圖目錄…………………………………………………………………Ⅶ
第一章 前言…………………………………………………………1
1. 1研究動機……………………………………………………………1
1. 2本論文之架構………………………………………………………2
第二章 光學低通濾波器的基本原理…………………………………3
2.1 疊紋(Moiré)現象產生的原因………………………………………3
2.1.1 如何判斷影像的品質與疊紋訊號的發生………………………7
2.2 概述消除疊紋效應的方法…………………………………………9
2.2.1 離焦法……………………………………………………………9
2.2.2 雙折射(單軸)晶體………………………………………………10
2. 2. 2. 1 影像重疊的原則…………………………………………11
2. 2. 2. 2 雙折射(單軸)晶體光學低通濾波器的設計……………13
2.2.3相位式繞射光柵…………………………………………………15
第三章 薄膜相位式繞射光柵的設計………………………………17
3. 1光柵的規格及符號說明……………………………………………17
3. 2 光柵設計原理……………………………………………………18
3. 3. 1光強分佈推導…………………………………………………18
3. 3. 2 MTF的推導……………………………………………………20
3. 3 光柵參數分析……………………………………………………24
3. 3. 1 光柵參數分析---與週期個數的關係………………………24
3. 3. 2 光柵參數分析---與分光距離的關係………………………25
3. 3. 3 光柵參數分析---與蝕刻深度的關係………………………29
3. 3. 4 光柵參數分析---與Duty Cycle的關係……………………34
3. 4 相位式繞射光柵設計……………………………………………37
第四章 薄膜相位式繞射光柵的製作…………………………………39
4. 1 製程設備…………………………………………………………39
4. 2 薄膜製程…………………………………………………………40
4. 2. 1 製程注意事項………………………………………………40
4. 2. 2 製程步驟……………………………………………………42
第五章 元件光學特性量測…………………………………………43
5. 1 光柵表面分析……………………………………………………43
5. 2 光柵MTF量測分析………………………………………………46
5. 3 數位元影像測試…………………………………………………49
第六章 討論與未來發展………………………………………………52
6. 1 設計討論…………………………………………………………52
6. 2 製程討論…………………………………………………………53
6. 3 量測討論…………………………………………………………55
6. 4 未來發展…………………………………………………………56
參考文獻………………………………………………………………58

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