疊紋原理應用在二維解合影像多重防偽 技術之研究

Abstract

現今防偽技術區分為三線，解合影像需要藉輔助儀器作驗證，是屬於二線防偽的種類。過去在其研究與應用上多採用一維結構的影像分割做為防偽設計的應用，並搭配光柵進行防偽解密。但在二線防偽之中，使用二維結構影像分割做為防偽設計的相關研究與實際使用上則屬少數。本研究鎖定在二維結構進行影像分割，配合多重陣列排列方法進行防偽設計，並使用微透鏡陣列做為防偽解密的工具。此種設計著重於防偽細微影像被放大仍無法辨識原影像內容，搭配多重分割排列組合可進而達成多重防偽效果。本研究將以實驗法進行，其中網屏解碼影像是本研究的基礎。論文中提出利用疊紋公式，依微透鏡陣列材料的週期計算出防偽文字影像的加密參數，之後將文字影像分割成不同等分與排列組合，並搭配不同組合進行合併，完成多重排列組合的單一加密影像，並輸出防偽用底片，最後選用正確週期與排列方式的微透鏡陣列，還原先前未分割的文字影像達到解密的效果，經實驗證明本研究推論是可行的。

Anti-counterfeiting technologies are often divided into three classes: first line, second line and third line. Image scrambling technology belongs to the second line anti-counterfeiting technology. In second line inspection, the document is authenticated by simple tools. For academic research and industrial applications, the 1-D image scrambling technology and the lenticular lens, as the decryption tools, have been commonly used for anti-counterfeiting design. By contrast, the researches and applications related to the 2-D scrambled images are much less addressed. Therefore, this study focuses on using 2-D scrambled images with multiple arrangements to enhance the anti-counterfeiting functions. The micro-lens array is adopted as the decryption tool. In addition, the proposed method makes the scrambled images cannot be recognized even when they have been enlarged, to achieve the multiple anti-counterfeiting features. This study uses the experimental method. And the screen-decoded images are the basic elements. The formula of moiré is also applied to obtain the encryption parameters of scrambled images, basing on the periods of selected micro-lens array. In this research, the scrambled images will be divided into varied combinations to construct a single encryption image with multiple arrangements. The results show that observing the output negative through the micro-lens array with proper resolution, the scrambled images can be restored to the original image successfully, to prove the feasibility of the proposed method.