Two New Steganographic Methods for Data Hiding in General 2D Bar Codes

[[abstract]]資訊隱藏的技術近年來被廣泛的應用在音訊、影像及視訊等多媒體上。各種二維條碼也已被普遍的使用於紀錄各種資訊，包括產品代碼、網址及個人資訊等。一般二維 條碼係以模組為單位所組成，本計畫提出兩種在以矩形模組為基本單位的一般性二維條 碼中做資料隱藏之新方法。第一，在異色模組對中，利用水平及垂直微幅調整模組長寬 以嵌入資料。本方法提出模組對連動調整的技術，讓模組間無鋸齒狀發生，提升隱藏資 料後的不可察覺性。第二，以修改模組的邊角像素之像素值來嵌入資料，再利用雙線性內插法重新計算模組內其他像素之像素值，讓模組內部呈現漸層效果。本方法也提出讓 模組與鄰近同色模組之交界處，不會產生突兀顏色變化的技術。 本計畫所提出兩種在一般二維條碼嵌入資訊的方法，均不會破壞原二維條碼黑白 模組組合的次序，所以嵌入機密資訊後之二維條碼仍能以標準條碼解碼器正確讀取原標示資訊。[[abstract]]Data hiding techniques are used on many different fields recently, such as audio, image, and video. Various kinds of 2D bar codes are also used widely on recording many kinds of information, such as product identification, website addresses and personal information etc., 2D bar codes are generally composed by modules. This project proposes two data hiding methods in general 2D bar codes with rectangular modules. Firstly, in a pair of modules with different color, the embedding process was accomplished by slightly adjusting modules’ horizontal lengths and vertical widths. The purposed technique for adjusting modules can eliminate uneven shapes among modules, which also improves the invisibility after data embedding. Secondly, to embed information by changing pixel value of corner pixels in a module, and use bilinear interpolation method to estimate other pixel values in the module. It makes the module represents gradient look. The purposed approach also has no edge effects in the boundary between gradient module and surrounding module with the same color. Both two proposed data hiding methods of general 2D bar codes will not disturb the combination and order of black and white modules. So, the original information in 2D bar codes which were embedded secret information can be correctly read out by standard bar code readers.[[note]]NSC102-2221-E327-02