Mutual-information Descriptors Research Articles

Video tamper detection based on multi-scale mutual information

Video frame manipulation has become commonplace with the growing easy access to powerful computing abilities. One of the most common types of video frame tampers is the copy-paste tamper, wherein a region from a video frame is replaced with another region from the same frame. In order to improve the robustness of passive video tampering detection, we propose a content-based video similarity tamper passive blind detection algorithm based on multi-scale normalized mutual information which can implement video frame copy, frame insertion and frame deletion tamper detection. The detail implementation of the proposed algorithm consists of multi-scale content analysis, single-scale content similarity measure, multi-scale content similarity measure, and tampering positioning. Firstly, we get the scales of the visual content of the video frame using Gaussian pyramid transform; Secondly, to measure the similarity of single-scale visual content, we define adjacent normalized mutual information of two frames according to information theory; Thirdly, we construct the multi-scale normalized mutual information descriptors to achieve the multi-scale visual content similarity measure of adjacent two frames using a linear combination. Finally, we use the local outlier isolated factor detection algorithm to detect the position of the video tampering. Experimental results show that the proposed approach can not only detect the video frame tampering position of delete, copy, and insert effectively, but also can detect the tampering of different and homology video encoding formats. We obtain a feature detecting accuracy in excess of 93% and detection rate of 96% across post processing operations, and are able to detect the delete, copy, and insert regions with a high true positive rate and lower false positive rate than the existing time field tamper detection methods.

A novel image retrieval method based on hybrid information descriptors

In this paper, we propose a novel image retrieval method called hybrid information descriptors (HIDs) consisting of mutual information descriptors (MIDs) and self information descriptors (SIDs). Based on the physiological structure of human eyes and visual perception mechanism, HIDs are designed to explore the internal correlations among different image feature spaces with image structure and multi-scale analysis, not only characterizing the low-level features, such as color, shape and texture, but also imitating the process of visual information transfer and perception in high-level understanding with the help of the proposed visual optimization model for feature fusion. Comparing with other existing methods applied to content-based image retrieval (CBIR) on four datasets, the usefulness and effectiveness of the HIDs are shown. Extensive experimental results can also demonstrate this.

Information-Scattering Perspective on Orbital Hybridization

Within the communication theory of the chemical bond, the transformation of atomic orbitals (AO) into molecular orbitals (MO) generates the information system for the associated electronic promotion of AOs in a molecule. It consists of the two orbital-mixing stages involving AOs and MOs, and one MO-occupation subchannel. The conditional-entropy and mutual-information descriptors of this resultant "communication" system, which measure the average "noise" and the amount of information in the molecular channel, provide novel information-theoretic measures of the system bond covalency and ionicity, respectively. This information-theoretic approach to the many-center probability-scattering in AO resolution is now applied to the one-center orbital transformations to examine the entropic indices of an effective promotion of the canonical AO in alternative valence states of an atom, identified by different occupations of hybrid orbitals (HO). This phenomenon is first illustrated and tested using the simplest scheme of mixing two atomic orbitals in a generalized sp hybridization. The conditions for the maximum of the AO-promotion covalency are examined, and the shape independence of the orbital channels and their entropy/information descriptors for the equalized probability weights of HO in the specified atomic valence state is commented upon. Entropic indices are then generated for selected valence states of the carbon atom, resulting from different hybridization schemes, in order to characterize their complementary aspects of the system electron polarization (one-center ionicity) and electron delocalization (one-center covalency). The interpretation of these components as measures of a degree of the acquired "order" and surviving "disorder" (electron uncertainty) in the valence state is also given. These results are found to generally agree with intuitive expectations. The exact HO-occupation subchannel is derived, which reproduces the average AO occupations in the valence state. This approach is also proposed for the multicenter probability scattering in molecules, via the system occupied MO, in probing the system chemical bonds.

Molecular communication channels of model excited electron configurations†

In the Communication Theory of the chemical bond, molecular systems are interpreted in atomic resolution as the information channels, in which ‘signals' of the electron allocations to constituent atoms are propagated from the molecular/promolecular input (‘source'), to the molecular output (‘receiver'). The electron delocalization throughout the system is responsible for the effective ‘noise' affecting the transmission of such atom-assignment signals. The conditional entropy and mutual-information descriptors of such molecular communication channels, measuring the average noise and the amount of information flowing through the molecular channel, respectively, provide measures of the covalent and ionic bond components, respectively. This work examines the influence of the relative phases of the atomic orbitals (AO) in the occupied molecular orbitals (MO) on these entropy/information indices of the chemical bond in the 2-AO, two-electron model. First, the singly- and doubly-excited-state configurations of the model are examined to investigate the influence of the occupied bonding and anti-bonding molecular orbitals on the previously proposed (phase-insensitive) entropy/information descriptors of the ground-state configuration. They in principle correctly identify the non-bonding character of the singly-excited configuration, but fail to recognize the anti-bonding character of the doubly-excited state. This is because the relative phases of AO in MO and those of the elementary valence-bond structures in the configuration wave-function are lost in the corresponding electron probabilities, which determine the molecular channel. A resolution of this difficulty is proposed through partition of the overall input probabilities of the molecular channel into the partial (phase-dependent) ‘forward' and ‘backward' inputs, which determine the entropy/information flows associated with the ‘positive' and ‘negative' phases of the wave-function components in the AO representation. †Dedicated to Professor A. Sadlej on the occasion of his 65th birthday.

Comparison between valence bond and communication theories of the chemical bond in H2

In the communication theory of the chemical bond the molecular systems in atomic resolution are interpreted as information channels, in which ‘signals' of the electron allocations to constituent atoms are propagated from the molecular/promolecular input (source), determined by either the free atoms of the promolecule or the bonded atoms in the molecule, to the molecular output (receiver) of atoms in molecules. The transmission network of the system chemical bonds is determined by the molecular conditional two-electron probabilities in atomic resolution. The electron delocalization throughout the system is responsible for the effective ‘noise' affecting the transmission of such atom-assignment signals, which inhibits the amount of information passing through the molecular communication system. The conditional entropy and mutual information descriptors of such molecular communication channels, measuring the average noise and the amount of information flowing through the molecular channel, accordingly, provide the overall measures of the covalent and ionic bond components, respectively. The communication theory approach to the chemical bond in H2 is compared with the familiar valence bond (VB) description of Heitler and London. In the information-theoretic (IT) approach the non-bonding, purely covalent, and purely ionic combinations of the elementary VB structures are defined and their information channels are discussed. It is demonstrated, that the VB covalent and VB ionic components of the molecular ground state wavefunction are in fact both IT ionic. The purely IT covalent components of the molecular ground state are established and their communication channels are examined. The communication origins of the information ionicity and entropy covalency are identified and a distinction between the electron-sharing (covalent) and pair-sharing (coordination) bonds is briefly explored.

Communication Theory Approach to the Chemical Bond

Recently proposed communication theory treatment of the chemical bond is outlined. The molecular systems in atomic resolution are interpreted as “communication” systems in which “signals” of the electron allocations to constituent atoms are propagated from the molecular input (source), e.g., the atomic promolecule reference, to the molecular output (receiver) via a network defined by the conditional two-electron probabilities. The electron delocalization accompanying the bond formation is responsible for the noise affecting the flow of information throughout the system. The conditional entropy and mutual information descriptors of such molecular communication channels are identified as overall measures of the covalent and ionic components of the system chemical bonds, and a distinction between the electron-sharing and coordination (donor–acceptor) bonds is investigated. These entropy/information descriptors of the chemical bond are illustrated in the two-electron, two-orbital model. This analysis covers the orbital and spin channels for the singlet (bonding) and triplet (nonbonding) states. The overall bond-order conservation in the model and the competition between the bond ionicity and covalency is stressed. The model polyatomic systems discussed include the π bonds in butadiene and benzene in the Huckel theory approximation. The predictions from the communication theory approach compare favorably with the chemical intuitive values and bond orders from other orbital approaches, e.g., the quadratic index of Wiberg and the two-electron multiplicities of the difference approach. The Hirshfeld partition of molecular electron density is briefly summarized and the average entropies of the local stockholder communication channel it generates are proposed as alternative information descriptors of the chemical bonds in molecules.