First-order multiples imaging aided by water bottom

Surface-related multiples frequently propagate into the subsurface and contain abundant information on small reflection angles.Compared with the conventional migration of primaries,migration of multiples offers complementary illumination and a higher vertical resolution.However,crosstalk artifacts caused by unrelated multiples during reverse time migration(RTM)using multiples severely degrade the reliability and interpretation of the final migration images.Therefore,we proposed RTM using first-order receiver-side water-bottom-related multiples for eliminating crosstalk artifacts and enhancing vertical resolution.We first backward propagate the first-order receiver-side water-bottom-related multiples using a water-layer model,followed by saving the upper boundary wavefield.Then we produce the source wavefield using a seismic wavelet and the receiver wavefield by back-extrapolating the saved boundary.Finally,the cross-correlation imaging condition is applied to generate the final image.This method transforms the receiver-side multiples into primaries,followed by the conventional migration processing procedures.Numerical examples using synthetic datasets demonstrate that our method significantly enhances the imaging quality by eliminating crosstalk artifacts and improving the resolution.

Near-field multiple super-resolution imaging from Mikaelian lens to generalized Maxwell's fish-eye lens

Super-resolution imaging is vital for optical applications, such as high capacity information transmission, real-time bio-molecular imaging, and nanolithography. In recent years, technologies and methods of super-resolution imaging have attracted much attention. Different kinds of novel lenses, from the superlens to the super-oscillatory lens, have been designed and fabricated to break through the diffraction limit. However, the effect of the super-resolution imaging in these lenses is not satisfactory due to intrinsic loss, aberration, large sidebands, and so on. Moreover, these lenses also cannot realize multiple super-resolution imaging. In this research, we introduce the solid immersion mechanism to Mikaelian lens(ML) for multiple super-resolution imaging. The effect is robust and valid for broadband frequencies. Based on conformal transformation optics as a bridge linking the solid immersion ML and generalized Maxwell's fish-eye lens(GMFEL), we also discovered the effect of multiple super-resolution imaging in the solid immersion GMFEL.

Three-dimensional positions of scattering centers reconstruction from multiple SAR images based on radargrammetry

A method and procedure is presented to reconstruct three-dimensional(3D) positions of scattering centers from multiple synthetic aperture radar(SAR) images. Firstly, two-dimensional(2D) attribute scattering centers of targets are extracted from 2D SAR images. Secondly, similarity measure is developed based on 2D attributed scatter centers' location, type, and radargrammetry principle between multiple SAR images. By this similarity, we can associate 2D scatter centers and then obtain candidate 3D scattering centers. Thirdly, these candidate scattering centers are clustered in 3D space to reconstruct final 3D positions. Compared with presented methods, the proposed method has a capability of describing distributed scattering center, reduces false and missing 3D scattering centers, and has fewer restrictionson modeling data. Finally, results of experiments have demonstrated the effectiveness of the proposed method.

A Visual Secret Sharing Scheme for Progressively Restoring Secrets

Visual secret sharing has received more and more attention over the past years due to the fact that neither complex computation nor cryptographic knowledge is required to decrypt the secret image directly according to the characteristics of the human vision system. Considering the issue of sharing the secret image at multiple image resolutions with the meaningful shadows, in this paper, we present a friendly progressive visual secret sharing scheme without expanding the image size in the shadows and the reconstructed secret image based on applying a 2x2-sized block-wise operation to generate the shadows block by block. The proposed method can achieve these benefits： 1） the generated shadows are meaningful, and their sizes are not expanded, and 2） the secret image can be recovered at different resolutions by stacking different quantities of shadows together. The experimental results also show that the proposed method is superior to other compared schemes.

Multiple Images Steganography of JPEG Images Based on Optimal Payload Distribution

Multiple images steganography refers to hiding secret messages in multiple natural images to minimize the leakage of secret messages during transmission.Currently,the main multiple images steganography algorithms mainly distribute the payloads as sparsely as possible inmultiple cover images to improve the detection error rate of stego images.In order to enable the payloads to be accurately and efficiently distributed in each cover image,this paper proposes a multiple images steganography for JPEG images based on optimal payload redistribution.Firstly,the algorithm uses the principle of dynamic programming to redistribute the payloads of the cover images to reduce the time required in the process of payloads distribution.Then,by reducing the difference between the features of the cover images and the stego images to increase the detection error rate of the stego images.Secondly,this paper uses a data decomposition mechanism based on Vandermonde matrix.Even if part of the data is lost during the transmission of the secret messages,as long as the data loss rate is less than the data redundancy rate,the original secret messages can be recovered.Experimental results show that the method proposed in this paper improves the efficiency of payloads distribution compared with existing multiple images steganography.At the same time,the algorithm can achieve the optimal payload distribution of multiple images steganography to improve the anti-statistical detection performance of stego images.

ULTRASHORT PULSE MULTISPECTRAL NON-LINEAR OPTICAL MICROSCOPY

Ultrashort pulse,multispectral non-linear optical microscopy(NLOM)is developed and used to image,simultaneously,a mixed population of cells expressing different fluorescent protein mutants in a 3D tissue model of angiogenesis.Broadband,sub-10-fs pulses are used to excite multiple fluorescent proteins and generate second harmonic in collagen.A 16-channel multispectral detector is used to delineate the multiple non-linear optical signals,pixel by pixel,in NLOM.The ability to image multiple fluorescent protein mutants and collagen,enables serial measurements of cell-cell and cell-matrix interactions in our 3D tissue model and characterization of fundamental processes in angiogenic morphogenesis.

Time-resolved multiple imaging by detecting photons with changeable wavelengths

Transporting information is one of the important functions of photons and is also the essential duty of information science. Here, we realize multiple imaging by detecting photons with changeable wavelengths based on time-resolved correlation measurements. In our system, information from multiple objects can be transported. During this process, the wavelength of the photons illuminating the objects is different from the wavelength of the photons detected by the detectors. More importantly, the wavelength of the photons that are utilized to record images can also be changed to match the sensitive range of the used detectors. In our experiment, images of the objects are reconstructed clearly by detecting the photons at wavelengths of 650, 810, and 1064 nm, respectively. These properties should have potential applications in information science.

Feasibility study of phase-sensitive imaging based on multiple reference optical coherence tomography

Multiple reference optical coherence tomography（MR-OCT） is a recently developed, low-cost and compact time-domain OCT solution for primary care and consumer level applications. A combination of a voice coil actuator and a partial mirror（PM） extends the scan range for imaging depths of approximately 1 mm in biological samples. Our previous research on MR-OCT is based only on intensity information obtained from the depth-resolved interference signal. In this Letter, we extract the phase information from the MR-OCT signal and, hence, provide an additional contrast modality. The phase sensitivity of the system is measured to be approximately 0.2 and 1.5 rad for the first and twelfth orders of reflection when using a mirror as the sample.This Letter describes first results of phase-sensitive data measured on a phantom obtained with MR-OCT. Data from a chick embryo chorioallantoic membrane（CAM） is used to demonstrate the feasibility of MR-OCT for in vivo phase-sensitive imaging.

3D image reconstruction with controllable spatial filtering based on correlation of multiple periodic functions in computational integral imaging

We propose a novel method of slice image reconstruction with controllable spatial filtering by using the correlation of periodic delta-function arrays （PDFAs） with elemental images in computational integral imaging. The multiple PDFAs, whose spatial periods correspond to object＇s depths with the elemental image array （EIA）, can generate a set of spatially filtered EIAs for multiple object depths compared with the conventional method for the depth of a single object. We analyze a controllable spatial filtering effect by the proposed method. To show the feasibility of the proposed method, we carry out preliminary experiments for multiple objects and present the results.

Five-level noncontiguous spinal injuries of cervical region： report of a case and literature review

The incidence of multiple noncontiguous spinal injuries （MNSI） in the cervical spine is rare but has catastrophic consequences. The patient in this report was a 34-year-old woman with five-level cervical MNSI. CT and MRI showed that injuries included atlantoaxial instability, burst fracture of C6, dislocation of C6/7, rupture of the intervertebal disc or ligamentous complex, and irreversible cord damage. The mechanism for this case was a combined pattern of hyperflexion, compression, and hyperextension injuries. A review of the literature revealed that this case is the first report in the literature of a vehicle related accident causing five-level noncontiguous injuries of the cervical spine.

The Multiple Images of Modernity

The multiple images of modernity are used here to put forward and corroborate the possibility of the genesis of multiple modern civilizations and their very modernity while confirming the prior existence of modern Western civilization. In examining the complexity, inner tensions and contemporary predicaments appearing in the formation and evolution of earlier Western modernity, this paper reveals the basic mechanisms of modernity and the various possible approaches to it, that is, the fact that there are more possibilities for modernity other than the Western one. Economic globalization is the first step and the only pathway towards the modernity goals of human society, and any deglobalization or antiglobalization will hinder or check the progress of human society towards the ideal goal of modernity. History and the real-world economy demonstrate that “building a community with a shared future for mankind” is so far a more suitable and more explanatory guiding concept for seeking and approaching the human ideal of modernity;it surpasses existing concepts such as “ecumenicalism,” “cosmopolitanism,” and “globalism,” and is the latest understanding of the modernity of human society in contemporary China.