3D medical images security via light-field imaging.

This Letter proposes a selective encryption scheme for three-dimensional (3D) medical images using light-field imaging and two-dimensional (2D) Moore cellular automata (MCA). We first utilize convolutional neural networks (CNNs) to obtain the saliency of each elemental image (EI) originating from a 3D medical image with different viewpoints, and successfully extract the region of interest (ROI) in each EI. In addition, we use 2D MCA with balanced rule to encrypt the ROI of each EI. Finally, the decrypted elemental image array (EIA) can be reconstructed into a full-color and full-parallax 3D image using the display device, which can be visually displayed to doctors so that they can observe from different angles to design accurate treatment plans and improve the level of medical treatment. Our work also requires no preprocessing of 3D images, which is more efficient than the method of using slices for encryption.

Deep-learning-based 3D object salient detection via light-field integral imaging.

This Letter proposes an effective light-field 3D saliency object detection (SOD) method, which is inspired by the idea that the spatial and angular information inherent in a light-field implicitly contains the geometry and reflection characteristics of the observed scene. These characteristics can provide effective background clues and depth information for 3D saliency reconstruction, which can greatly improve the accuracy of object detection and recognition. We use convolutional neural networks (CNNs) to detect the saliency of each elemental image (EI) with different viewpoints in an elemental image array (EIA) and the salient EIA is reconstructed by using a micro-lens array, forming a 3D salient map in the reconstructed space. Experimental results show that our method can generate high-quality 3D saliency maps and can be observed simultaneously from different angles and positions.

Color ghost imaging through the scattering media based on A-cGAN.

Ghost imaging plays an important role in the field of optical imaging. To realize color ghost imaging through the scattering media, we propose a deep learning method with high generation ability. Through our method, we can efficiently reconstruct color images with rich details, in line with human perception and close to the target color pictures. Experimental results show that our method can image through the scattering media with different scattering intensities and achieve good results even at a sampling rate of 0.1.

Cryptanalysis for a light-field 3D cryptosystem based on M-cGAN.

Integral imaging, as an excellent light-field three-dimensional (3D) imaging technique, is considered as one of the most important technologies for 3D encryption because of its obvious advantages of high robustness, security, and computational feasibility. However, to date, there is no effective cryptanalysis technology for the light-field 3D cryptosystem. In this Letter, a cryptanalysis algorithm based on deep learning for the light-field 3D cryptosystem is presented. The 3D image can be optically retrieved by the trained network model without encryption keys. The experimental results verify the feasibility and effectiveness of our proposed method.

SP1-induced lncRNA DANCR contributes to proliferation and invasion of ovarian cancer.

Transcription factor SP1 could manipulate pathways involved in ovarian cancer progression. LncRNAs are involved in SP1-mediated tumorigenesis. LncRNA DANCR could promote metastasis of ovarian cancer. However, the regulatory function and involvement of SP1-induced lncRNA DANCR in ovarian cancer remain elusive. Data from this study showed that SP1 was up-regulated in ovarian cancer tissues and cells (CAOV3, SKOV3, A2780), and SP1 could bind to the promoter region of DANCR through chromatin immunoprecipitation and leuciferase activity assays. Therefore, DANCR was transcriptionally induced by SP1 in ovarian cancer tissues and cells (CAOV3, SKOV3, A2780). Functionally, reduced expression of DANCR suppressed cell viability, migration and invasion of CAOV3, while enhanced DANCR expression contributed to SKOV3 growth. Over-expression of SP1 reversed the suppressive effects of DANCR interference on ovarian cancer progression. In conclusion, SP1-induced DANCR contributed to oncogenic potential of ovarian cancer, suggesting a promising therapeutic target for ovarian cancer.

Integral imaging-based 2D/3D convertible display system by using holographic optical element and polymer dispersed liquid crystal.

An integral imaging-based 2D/3D convertible display system is proposed by using a lens-array holographic optical element (LAHOE), a polymer dispersed liquid crystal (PDLC) film, and a projector. The LAHOE is closely attached to the PDLC film to constitute a projection screen. The LAHOE is used to realize integral imaging 3D display. When the PDLC film with an applied voltage is in the transparent state, the projector projects a Bragg matched 3D image, and the display system works in 3D mode. When the PDLC film without an applied voltage is in the scattering state, the projector projects a 2D image, and the display system works in 2D mode. A prototype of the integral imaging-based 2D/3D convertible display is developed, and it provides 2D/3D convertible images properly.

Evolution of optical properties and electronic structures: band gaps and critical points in MgxZn1-xO (0 ≤ x ≤ 0.2) thin films.

MgxZn1-xO (ZMO) thin films with tunable Mg content were deposited by atomic layer deposition (ALD) on silicon substrates at 190 °C. The elemental and structural properties were acquired by X-ray photoelectron spectroscopy, transmission electron microscopy, atomic force microscopy and X-ray diffraction. Spectroscopic ellipsometry measurements were performed to reveal the evolution of the dielectric functions and critical points in the ZMO thin films by point-by-point fit in the photon energy range of 1.2-6.0 eV. The dependence of the dielectric functions on doping content is clearly demonstrated and physically explained. The critical point energies and the types of interband optical transitions were extracted from standard lineshape analysis of the second derivatives of the dielectric functions. The critical point features were discussed in terms of band structure modification and structural homogeneity arisen by introducing the Mg dopant into the films. Controlling these transitions by changing the doping content will be of practical significance in emerging ZMO-based thin-film photonic and optoelectronic devices.

Optical Properties of Al-Doped ZnO Films in the Infrared Region and Their Absorption Applications.

The optical properties of aluminum-doped zinc oxide (AZO) thin films were calculated rapidly and accurately by point-by-point analysis from spectroscopic ellipsometry (SE) data. It was demonstrated that there were two different physical mechanisms, i.e., the interfacial effect and crystallinity, for the thickness-dependent permittivity in the visible and infrared regions. In addition, there was a blue shift for the effective plasma frequency of AZO when the thickness increased, and the effective plasma frequency did not exist for AZO ultrathin films (< 25 nm) in the infrared region, which demonstrated that AZO ultrathin films could not be used as a negative index metamaterial. Based on detailed permittivity research, we designed a near-perfect absorber at 2-5 µm by etching AZO-ZnO alternative layers. The alternative layers matched the phase of reflected light, and the void cylinder arrays extended the high absorption range. Moreover, the AZO absorber demonstrated feasibility and applicability on different substrates.

Dual-view-zone tabletop 3D display system based on integral imaging.

In this paper, we propose a dual-view-zone tabletop 3D display system based on integral imaging by using a multiplexed holographic optical element (MHOE) that has the optical properties of two sets of microlens arrays. The MHOE is recorded by a reference beam using the single-exposure method. The reference beam records the wavefronts of a microlens array from two different directions. Thus, when the display beam is projected on the MHOE, two wavefronts with the different directions will be rebuilt and the 3D virtual images can be reconstructed in two viewing zones. The MHOE has angle and wavelength selectivity. Under the conditions of the matched wavelength and the angle of the display beam, the diffraction efficiency of the MHOE is greatest. Because the unmatched light just passes through the MHOE, the MHOE has the advantage of a see-through display. The experimental results confirm the feasibility of the dual-view-zone tabletop 3D display system.

Effects of Bilayer Thickness on the Morphological, Optical, and Electrical Properties of Al2O3/ZnO Nanolaminates.

This report mainly focuses on the investigation of morphological, optical, and electrical properties of Al2O3/ZnO nanolaminates regulated by varying bilayer thicknesses. The growth mechanism of nanolaminates based on atomic layer deposition and Al penetration into ZnO layer are proposed. The surface roughness of Al2O3/ZnO nanolaminates can be controlled due to the smooth effect of interposed Al2O3 layers. The thickness, optical constants, and bandgap information of nanolaminates have been investigated by spectroscopic ellipsometry measurement. The band gap and absorption edge have a blue shift with decreasing the bilayer thickness on account of the Burstein-Moss effect, the quantum confinement effect and the characteristic evolution of nanolaminates. Also, the carrier concentrations and resistivities are found to be modified considerably among various bilayer thicknesses. The modulations of these properties are vital for Al2O3/ZnO nanolaminates to be used as transparent conductor and high resistance layer in optoelectronic applications.

Dielectric functions and critical points of crystalline WS2 ultrathin films with tunable thickness.

Centimeter-scale WS2 ultrathin films were synthesized on sapphire substrates, and they showed highly oriented crystallographic growth along the c axis. Afterwards, the as-grown samples were systematically characterized using various detection methods. Reliable values of the roughness layer thickness and the film thickness were extracted using both atomic force microscopy (AFM) and spectroscopic ellipsometry (SE), and identified using Raman spectroscopy as well. The expansion and tensile strain along the [001] direction were discovered using X-ray diffraction (XRD) measurements. Accurate dielectric functions of WS2 films were derived from the point-by-point fitting results. The critical points (CPs) of WS2, which have not been reported so far, are precisely extracted from the standard critical point (SCP) model. Their origins are uniquely assigned to different interband electronic transitions in the Brillouin zone, including some novel optical structures above 3 eV, which were not investigated in earlier studies. In this work, it is found that dielectric functions are thickness-dependent, while CPs have an opposite nature, and their intrinsic mechanisms are revealed. The as-obtained results can be expected to help people develop more extensive applications of WS2.

Optical Constants and Band Gap Evolution with Phase Transition in Sub-20-nm-Thick TiO2 Films Prepared by ALD.

Titanium dioxide (TiO2) ultrathin films with different thicknesses below 20 nm were grown by atomic layer deposition (ALD) on silicon substrates at 300 °C. Spectroscopic ellipsometry (SE) measurements were operated to investigate the effect of thickness on the optical properties of ultrathin films in the spectra range from 200 to 1000 nm with Forouhi-Bloomer (F-B) dispersion relation. It has been found that the refractive index and extinction coefficient of the investigated TiO2 ultrathin film increase while the band gap of TiO2 ultrathin film decreases monotonically with an increase in film thickness. Furthermore, with the purpose of studying the temperature dependence of optical properties of TiO2 ultrathin film, the samples were annealed at temperature from 400 to 900 °C in N2 atmosphere. The crystalline structure of deposited and annealed films was deduced by SE and supported by X-ray diffraction (XRD). It was revealed that the anatase TiO2 film started to transform into rutile phase when the annealing temperature was up to 800 °C. In this paper, a constructive and effective method of monitoring the phase transition in ultrathin films by SE has been proposed when the phase transition is not so obvious analyzed by XRD.

Effects of a Small Interfering RNA Targeting YKL-40 Gene on the Proliferation and Invasion of Endometrial Cancer HEC-1A Cells.

OBJECTIVE: The purpose of this study was to explore the effects of a small interfering RNA (siRNA) targeting YKL-40 on the proliferation and invasion of endometrial cancer (EC) HEC-1A cells. METHODS: We used an siRNA targeting a sequence in YKL-40 (si-YKL-40) to transfect HEC-1A cells. Quantitative real-time polymerase chain reaction assay was performed to investigate the mRNA levels of YKL-40. MTT, migration, and invasion assays were performed to identify the effects of si-YKL-40 on the proliferation, migration, and invasive abilities of the HEC-1A cells. RESULTS: mRNA expression of YKL-40 was down-regulated in HEC-1A cells after transfection with si-YKL-40 (P < 0.05). The proliferation, migration, and invasive abilities of HEC-1A cells were inhibited by siRNA (P < 0.05). CONCLUSIONS: YKL-40 targeting siRNA specifically blocks the activity of YKL-40 in human EC HEC-1A cells, resulting in tumor suppression. This indicates that YKL-40 might serve as a potential small molecule target in the treatment of EC.

Active integral imaging system based on multiple structured light method.

In this paper, we simplify the equipments for integral imaging (II) pickup and implement an active II system based on multiple structured light (MSL) method. In the active II system, the complete three-dimensional (3D) shape of the 3D scene can be reconstructed, and the tunable parallaxes can be generated without occlusions. Therefore, the high-quality 3D images can be displayed efficiently by the II. We also use the Compute Unified Device Architecture implementing the processing algorithms in graphics processing unit. The experimental results demonstrate the effectiveness of the MSL method for the II pickup and the acceleration for the elemental image array generation. Especially, the proposed method is suitable for the real scene with high precision.

Using a laser source to measure the refractive index of glass beads and Debye theory analysis.

Using a monochromatic laser beam to illuminate a homogeneous glass bead, some rainbows will appear around it. This paper concentrates on the study of the scattering intensity distribution and the method of measuring the refractive index for glass beads based on the Debye theory. It is found that the first rainbow due to the scattering superposition of backward light of the low-refractive-index glass beads can be explained approximately with the diffraction, the external reflection plus the one internal reflection, while the second rainbow of high-refractive-index glass beads is due to the contribution from the diffraction, the external reflection, the direct transmission, and the two internal reflections. The scattering intensity distribution is affected by the refractive index, the radius of the glass bead, and the incident beam width. The effects of the refractive index and the glass bead size on the first and second minimum deviation angle position are analyzed in this paper. The results of the measurements agree very well with the specifications.

Dual-view integral imaging 3D display using polarizer parallax barriers.

We propose a dual-view integral imaging (DVII) 3D display using polarizer parallax barriers (PPBs). The DVII 3D display consists of a display panel, a microlens array, and two PPBs. The elemental images (EIs) displayed on the left and right half of the display panel are captured from two different 3D scenes, respectively. The lights emitted from two kinds of EIs are modulated by the left and right half of the microlens array to present two different 3D images, respectively. A prototype of the DVII 3D display is developed, and the experimental results agree well with the theory.

Tilted elemental image array generation method for moiré-reduced computer generated integral imaging display.

In this paper, we propose a tilted elemental image array generation method for computer generated integral imaging display with reduced moiré patterns. The pixels of the tilted elemental image array are divided into border pixels and effective pixels. According to the optimal tilted angle, the effective pixels are arranged with uniform arrangement. Also, a pixel mapping method is proposed. Appropriate experiments are carried out and the experimental results show that not only the color moiré patterns are reduced remarkably, but also the resolution of the reconstructed 3D images are improved through the proposed method.

Dual-view integral imaging three-dimensional display.

In this paper, we propose a dual-view integral imaging (DVII) three-dimensional (3D) display that presents different 3D images in the left and right viewing directions simultaneously. The DVII 3D display consists of a display panel and a microlens array, and its elemental image array (EIA) is composed of two sub-EIAs. The sub-EIAs captured for two different 3D scenes are responsible for two different 3D images in the left-view and right-view integral imaging 3D displays, respectively. A prototype of the DVII 3D display using a pinhole array is developed, and good results are obtained.

Autostereoscopic three-dimensional display based on two parallax barriers.

An autostereoscopic three-dimensional (3D) display composed of a flat-panel display, two parallax barriers, and a backlight panel is proposed. Parallax barrier 1, located between the backlight panel and the flat-panel display, divides the lights to create the perception of stereoscopic images. Parallax barrier 2, located between the flat-panel display and the viewers, acts as the function of decreasing the cross talk of the stereoscopic images. The operation principle of the display and the calculation equations for the parallax barriers are described in detail. An autostereoscopic 3D display prototype is developed. The prototype presents high-quality stereoscopic images. At the optimal viewing distance, it presents stereoscopic images without cross talk. At other viewing distances, it has less cross talk than a conventional autostereoscopic 3D display based on one parallax.

Cross-talk reduction by correcting the subpixel position in a multiview autostereoscopic three-dimensional display based on a lenticular sheet.

A method is proposed to alleviate the cross talk in multiview autostereoscopic three-dimensional displays based on a lenticular sheet. We analyze the positional relationship between subpixels on the image panel and the lenticular sheet. According to this relationship, optimal synthetic images are synthesized to minimize cross talk by correcting the positions of subpixels on the image panel. Experimental results show that the proposed method significantly reduces the cross talk of view images and improves the quality of stereoscopic images.