人們由於網路的便利,可以自由地傳遞資訊,但同時也存在著不安全,必需讓資訊進行隱藏且不被竊取,所以學者們不斷地提出新的資訊隱藏方法。另外,資訊隱藏又分為「可逆資訊隱藏」與「不可逆資訊隱藏」,早期許多資訊隱藏技術無法進行恢復,所以在改變影像結構後,就無法提取正確資訊,後期學者們陸續提出可恢復的資訊隱藏技術,改善不可逆資訊隱藏的問題,其中影像品質與藏量通常是用來比較利弊的標準。因此,許多學者們會針對減少像素修改量,並以提高影像品質,例如:LSB匹配法與雙影像技術等。本研究以Lu等學者的LSB匹配法及雙影像技術做改良,將最大像素修改量為2,縮減為1。第一步驟是以兩個原始像素為一組,更改成以一個像素為一組,將原始影像複製成兩張原始影像;第二步驟是使用改良式LSB匹配法,將兩個機密訊息分別藏入第一張原始影像與第二張原始影像中。最後步驟是產生兩張偽裝影像。實驗結果顯示,利用LSB匹配法與雙影像技術,可以達到良好的影像品質與藏量,並且在RS分析法的偵測下,達到良好的效果,機密訊息的存在無法被發現,因此不容易被有心人士攻擊。
People are free to pass information because of the convenience of the Internet. However the Internet is insecure, it is necessary to protect the secret information from stealing. Scholars are constantly proposing new ways for data hiding. In addition, data hiding is divided into "reversible data hiding" and "irreversible data hiding". Most of early data hiding technologies are irreversible data hiding, the image cannot be recovered after extracting the secret information. Lately scholars propose recoverable data hiding techniques to improve the problem of irreversible data hiding. Image quality and hiding capacity are usually used to compare the pros and cons. Therefore many scholars aim to reduce the amount of pixel modification and improve image quality by using LSB matching method and dual image technology. This study improved the dual image technology proposed by Lu et al., and the maximum pixel modification amount is reduced from 2 to 1, The first step copied the original image into two original images; the second step used the modified LSB matching method to hide two secret bit into the first original image and the second original image. The final step generated two stego images.The experimental results show that the proposed method of LSB matching method and dual image technology can achieve better hiding capacity and image quality. To detect the LSB steganograpgy, the RS analysis method is used. A good results have been obtained. The existence of secret message cannot be discovered, so it is not easy to be attacked by people who are interested.