應用於空間域上之資訊隱藏技術

A Study of Information Hiding in Spatial Domain

江威(Wei Jiang)

指導教授 ： 詹啟祥

亞洲大學/資訊學院/資訊多媒體應用學系碩士班/碩士(2011年)

摘要

本篇碩士論文提出兩個資訊隱藏的方法。第一個方法是由LSB Matching Revisited衍生而來，屬於不可回復式資訊隱藏技術；最初Mielkiainen所提出的 LSB Matching Revisited是作用在像素對中，其目的在減少藏入資訊時所必需修改的像素數目。而我們的方法則是作用在包含三個像素的像素集合中，每個像素集合會將它所包含的三個像素，以互斥或函式的方式循環串連，而後根據秘密資料位元，再對像素集合進行處理。根據實驗結果，第一個方法與Mielkiainen’s LSB Matching Revisited相比，需要修改的像素數可減少約一成。第二個方法屬於可回復式資訊隱藏技術(Reversible Data Hiding)，此方法利用中間邊緣預測法(Median Edge Detector, MED)，來取代Lee等人在做資訊隱藏時所使用的像素預測值方法。對於中間邊緣預測法所得到的像素預測值與原始像素值之差值，再運用差值擴張法(Difference Expansion, DE)嵌入秘密資訊位元。由於中間邊緣預測法有較高的預測準確度，所以根據實驗結果顯示，此方法的秘密資料藏入量高於Lee等人的方法的藏入量。

關鍵字

中間邊緣預測法 ； 差值擴張法 ； 可回復式資料隱藏

並列摘要

In this thesis, two information hiding methods are proposed. The first method derived from LSB Matching Revisited method is one of the irreversible information hiding technology. The original Mielkiainen’s LSB Matching Revisited method performed on pixel pairs to reduce the amount of pixel modifications. On the contrary, our method performs LSB Matching Revisited method on three-pixel sets. Each set comes from linking three pixels by using XOR operator. According to experimental results, the amount of pixels modifications of the proposed method is fewer than that of Mielkiainen’s method about 10%. As for the second method, it belongs to the reversible information hiding technology that replaces the predicted part of Lee at al.’s method with Median Edge Detector. The secret data are embedded to expanded difference between original pixel value and the predicted pixel value by using Difference Expansion method. Owing to the accurate pixel predictions from Median Edge Detector, the embedding capacity of our method is higher than that of Lee at al.’s method.

並列關鍵字

median edge detector ； difference expansion ； reversible data hiding

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