Authentication of secret information in image Steganography摘要

Authentication of secret information in image Steganography Babu, K.S.; Raja, K.B.; Kiran, K.K.; Manjula Devi, T.H.; Venugopal, K.R.; Patnaik, L.M.TENCON 2008 - 2008, TENCON 2008. IEEE Region 10 ConferenceVolume , Issue , 19-21 Nov. 2008 Page(s):1 - 6Digital Object Identifier 10.1109/TENCON.2008.4766581


Summary:
In recent years, steganography and steganalysis are two important areas of research that involve a number of applications. These two areas of research are important especially when reliable and secure information exchange is required. Steganography is an art of embedding information in a cover image without causing statistically significant variations to the cover image. Steganalysis is the technology that attempts to defeat steganography by detecting the hidden information and extracting. In this paper we propose an image steganography that can verify the reliability of the information being transmitted to the receiver. The method can verify whether the attacker has tried to edit, delete or forge the secret information in the stego-image. The technique embeds the hidden information in the spatial domain of the cover image and uses two special AC coefficients of the discrete wavelet transform domain to verify the veracity (integrity) of the secret information from the stego image. The analysis shows that the BER and PSNR is improved in the case of DWT than DCT.


摘要：
近年來，steganography跟steganalysis是兩個重要的研究領域，它包含對於數字的運用。這兩個領域的研究非常重要，特別是在可靠和安全的信息交流是必需的。Steganography是將訊息嵌入多媒體中，且使多媒體前後有太大的差異。Steganalysis是一個試圖透過檢測和提取隱藏信息來打敗steganography。在這份論文中我們建議，一個image steganography藉由可靠的接收器來審核訊息。這個方法可以驗證stego-image是否有被修改、刪除或偽造秘密訊息。這個在cover image的spatial domain嵌入隱藏訊息的技術，利用了小波轉換裡的兩個特別的AC係數去驗證stego image裡的機密訊息是否完整。這個分析說明了BER(位元錯誤率)跟PSNR(信噪比)改善了「小波轉換」上的「離散餘弦轉換」。


PSNR 說真的不是很懂...
有上網找了一下資料...
他說~
psnr的模型有兩個輸入訊號，分別名為I1和I2，I1可以是原始影像，I2可以是原始影像經過處理後的結果，根據PSNR的定義I1,I2兩者亦可對調，不影響結果。舉一個簡單的例子，讀入一張彩色影像，取出紅色部分(假設為I1 signal)，並將 I1訊號每個pixel加上0.01(假設為I2訊號)，其中0.01只是我隨便舉的一個雜訊干擾量。之後分別將I1和I2連接psnr block的input signal I1和I2 即可得到一個psnr數值。

可是越看越模糊 ！
不過大概可以知道PSNR是原始影像跟處理過的影像做比對的一個比值。