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摘要
In this paper we present a distortion-free data hiding algorithm which can embed secret messages into high dynamic range (HDR) images. Our scheme provides three significant benefits. First, it enables us to convey secret messages to produce a stego HDR image. When we operate the tone mapping technique to reduce the high contrast to a displayable range, no distortion is encountered between the tone-mapped cover and the stego images. A quantitative measure verifies that histograms of the cover and stego HDR images are correlated with linear dependency. To the best of our knowledge, our algorithm is the first approach in HDR literature that can provide capability of distortion-free data embedding. For the application of image annotation, the average capacity offered by our method is in the range of 0.12-0.29 bits per pixel. Our scheme provides an average capacity in the range of 0.0010-0.0026 bits per pixel for the application of image steganography where the stego HDR image preserves an HDR image encoding format which does not cause any suspicion by eavesdroppers. Second, our algorithm performs with adaptive message embedding where pixels conceal different amounts of secret messages based on their homogeneous representations. Quantitative analysis indicates that our algorithm offers an insignificantly small magnitude of the maximal pixel difference between the cover and stego HDR images. This feature and the histogram distribution of similarity between the cover and stego HDR images increase the difficulty of detecting whether any message is hidden in an HDR image. Third, our scheme is efficient. The time required for message embedding or extraction is in the range of several hundred milliseconds. Our approach belongs to a blind detection where the messages can be extracted without referring to the original cover HDR image. We believe our proposed scheme is suitable for applications such as image annotation or image steganography.
- 出版日期2011-12
