3D salient object detection based on light field integral imaging.

Potent usage of the multi-scale light field information for salient object detection (SOD) is the essential requirement of three-dimensional (3D) SOD. On this basis, a light field 3D-SOD scheme is proposed that employs the pixel mapping algorithm to achieve a more distinct representation of spatial and angular information in the four-dimensional (4D) light field, collaboratively mining the global saliency cues via the co-salient object detection (CoSOD) network. Compared with the previous method, our scheme filters out most of the noise by thoroughly leveraging the global dependence of the 4D light field, offering significant enhancements in saliency extraction performance and efficiency. Additionally, the 3D reconstruction results demonstrate the integral retention of the spatial and angular information of the original light field.

Color 3D display and security via monochrome scenes.

Color three-dimensional (3D) displays have always been the ideal display method because of their strong sense of reality, whereas color 3D displays of monochrome scenes are still challenging and unexplored. A color stereo reconstruction algorithm (CSRA) is proposed to solve the issue. We design a deep learning-based color stereo estimation (CSE) network to obtain color 3D information of monochrome scenes. The vivid color 3D visual effect is verified by our self-made display system. Furthermore, an efficient CSRA-based 3D image encryption scheme is achieved by encrypting a monochrome image with two-dimensional double cellular automata (2D-DCA). The proposed encryption scheme fulfills the requirement for real-time and high-security 3D image encryption with a large key space and the parallel processing capability of 2D-DCA.

Optical 3D object security and reconstruction using pixel-evaluated integral imaging algorithm.

Under the framework of computational integral imaging, an optical 3D objects security and high-quality reconstruction method based on pixel-evaluating mapping (PEM) algorithm is proposed. In this method, the pixel crosstalk caused by noneffective pixel overlap is effectively reduced by a pixel-evaluated mask, which can improve the image quality of the reconstructed 3D objects. Meanwhile, compared with the other computational integral imaging reconstruction methods, our proposed PEM algorithm can obtain more accurate pixel mapping weight parameters, thereby the reconstructed 3D objects provide higher quality. In addition, the nonlinear feedback shift register cellular automata algorithm is proposed to increase the security of the proposed method. We have experimentally verified the proposed 3D objects encryption and reconstruction algorithm. The experimental results show that the proposed method is superior to the other computational reconstruction methods.

Cost-effective 400-Gbps micro-intradyne coherent receiver using optical butt-coupling and FPCB wirings.

We present a cost-effective and bandwidth-enhanced 64-Gbaud micro-intradyne coherent receiver based on hybrid integration of InP waveguide-photodetector (WG-PD) and silica planar lightwave circuit (PLC). InP waveguide-photodetector (WG-PD) arrays are simply chip-to-chip bonded and optically butt-coupled to a silica-based dual-polarization optical hybrid chip. Multiple flexible printed circuit boards are adapted for electrical RF and DC wirings, which provide low-cost integration and good RF performance of the receiver. A 3-dB bandwidth of the fabricated coherent receiver is extended to ~36 GHz by optimization of bondwire inductance between the WG-PD array and the transimpedance amplifier (TIA), even when commercial TIAs with a typical bandwidth of ~29 GHz are used. Through optimization of the silica hybrid integrated coherent receiver, 64-Gbaud DP-16QAM signal transmission over 1050-km standard single-mode fiber is successfully demonstrated below a bit error rate of 2 × 10-3. This is the threshold for a soft decision-based forward error correction, at the optical signal to noise ratio of 23.8 dB.

Designing optical 3D images encryption and reconstruction using monospectral synthetic aperture integral imaging.

This paper realizes an optical 3D images encryption and reconstruction by employing the geometric calibration algorithm to the monospectral synthetic aperture integral imaging system. This method has the simultaneous advantages of improving the quality of 3D images by eliminating the crosstalk from the unaligned cameras and increasing security of the multispectral 3D images encryption by importing the random generated maximum-length cellular automata into the Fresnel transform encoding algorithm. Furthermore, compared with the previous 3D images encryption methods of encrypting 3D multispectral information, the proposed method only encrypts monospectral data, which will greatly minimize the complexity. We present experimental results of 3D image encryption and volume pixel computational reconstruction to test and verify the performance of the proposed method. Experimental results validate the feasibility and robustness of our proposed approach, even under severe degradation.

Optical encryption via monospectral integral imaging.

Optical integral imaging (II) uses a lenslet array and CCD sensor as the 3D acquisition device, in which the multispectral information is acquired by a color filter array (CFA). However, color crosstalk exists in CFA that diminishes color gamut, resulting in the reduced resolution. In this paper, we present a monospectral II encryption approach with a monospectral camera array (MCA). The monospectral II system captures images with the MCA that can eliminate color crosstalk among the adjacent spectral channels. It is noteworthy that the captured elemental images (EIs) from the colored scene belong to grayscale; the colored image encryption is converted to grayscale encryption. Consequently, this study will significantly save the calculation load in image encoding and decoding (nearly reduced 2/3) compared with the similar works. Afterwards, an optimized super-resolution reconstruction algorithm is introduced to improve the viewing resolution.

Copyright protection for elemental image array by hypercomplex Fourier transform and an adaptive texturized holographic algorithm.

In practical applications of three-dimensional integral imaging, the captured elemental image array (EIA) needs to be stored and delivered through the Internet. Therefore, there is an urgent need for protecting the copyright of EIA against piracy and malicious manipulation. In our work, we propose a copyright protection algorithm for EIA by combining the use of the modified hypercomplex Fourier transform (HFT) and the adaptive texturized holographic algorithm. The modified HFT can accurately extract the features from each elemental image. According to these features, we embed watermark into the visually less noticeable regions of the EIA to increase the visual perception. In addition, an adaptive texturized holographic algorithm is proposed to increase the robustness. Finally, the analytical performances are contrasted with simulation results where the imperceptibility and robustness of the proposed method are evaluated against standard attacks.

Radiation fields and dose assessments in Korean nuclear power plants.

In the primary systems of nuclear power plants (NPPs), various radionuclides including fission products and corrosion products are generated due to the complex water chemistry conditions. In particular, (3)H, (14)C, (58)Co, (60)Co, (137)Cs, and (131)I are important or potential radionuclides with respect to dose assessment for workers and the management of radioactive effluents or dose assessment for the public. In this paper, the dominant contributors to the dose for workers and the public were reviewed and the process of dose assessment attributable to those contributors was investigated. Furthermore, an analysis was carried out on some examples of dose to workers during NPP operation.