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With the rapid development of the electronic medical information systems and Internet technology, the frequency of electronic medical records (EMRs) and electronic patient information (EPIs) transmitted over the Internet and shared among authorized medical parties is gradually increased. Reversible data hiding in medical images is an efficient technique to embed an EPI or EMR into a medical image, such as X-ray, MRI etc. In this paper, a reversible data hiding scheme by using enhanced neighbor mean interpolation (ENMI) technology is proposed to expand each 22 block in the original image to a 33 block. The four original pixels remaining at the four corners in each expanded block. Five derived pixels by using the ENMI interpolation algorithm are used to carry 4-bits secret data and a 1-bit authentication code with our proposed efficient data hiding strategy. Experimental results confirm that the detection performance and the robustness of the hidden data with our proposed scheme are significantly higher than that of the Geeth & Geeth scheme and other six representative schemes.

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During transmission of digital images, secret messages can be embedded using data hiding techniques. Such techniques can transfer private secrets without drawing the attention of eavesdroppers. To reduce the amount of transmitted data, image compression methods are widely applied. Hiding secret data in compressed images is a hot issue recently. In this paper, we apply the de-clustering concept and the indicator-free search-order coding (IFSOC) technique to hide information into vector quantization (VQ) compressed images. Experimental results show that the proposed two-layer reversible data hiding scheme for IFSOC-encoded VQ index table can hide a large amount of secret data among state-of-the-art methods with a relatively lower bit rate and high security.

A complex spherical code is a finite subset on the unit sphere in C d . A fundamental problem on complex spherical codes is to find upper bounds for those with prescribed inner products. In this paper, we determine the irreducible decomposition under the action of the one-point stabilizer of the unitary group U (d) on the polynomial ring C[z1 . . . , z d , z1, . . . , zd ] in order to obtain the semidefinite programming bounds for complex spherical codes.