3D human modeling from a single depth image dealing with self-occlusion

This paper presents a 2D to 3D conversion scheme to generate a 3D human model using a single depth image with several color images. In building a complete 3D model, no prior knowledge such as a pre-computed scene structure and photometric and geometric calibrations is required since the depth camera can directly acquire the calibrated geometric and color information in real time. The proposed method deals with a self-occlusion problem which often occurs in images captured by a monocular camera. When an image is obtained from a fixed view, it may not have data for a certain part of an object due to occlusion. The proposed method consists of following steps to resolve this problem. First, the noise in a depth image is reduced by using a series of image processing techniques. Second, a 3D mesh surface is constructed using the proposed depth image-based modeling method. Third, the occlusion problem is resolved by removing the unwanted triangles in the occlusion region and filling the corresponding hole. Finally, textures are extracted and mapped to the 3D surface of the model to provide photo-realistic appearance. Comparison results with the related work demonstrate the efficiency of our method in terms of visual quality and computation time. It can be utilized in creating 3D human models in many 3D applications.     

Slotted capacitive microphone with sputtered aluminum diaphragm and photoresist sacrificial layer

In this paper, we have fabricated a new microphone using aluminum (Al) slotted perforated diaphragm and back plate electrode, and photoresist (AZ1500) sacrificial layer on silicon wafer. The novelty of this method relies on aluminum diaphragm includes some slots to reduce the effect of residual stress and stiffness of diaphragm for increasing the microphone sensitivity. The acoustic holes are made on diaphragm to reduce the air damping, and avoid the disadvantages of non standard silicon processing for making back chamber and holes in back plate, which are more complex and expensive. Photoresist sacrificial layer is easy to deposition by spin coater and also easy to release by acetone. Moreover, acetone has a high selectivity to resist compared to silicon oxide and Al, thus it completely removes sacrificial resist without incurring significant damage silicon oxide and Al. The measured zero bias capacitance is 17.5 pF, and its pull-in voltage is 25 V. The microphone has been tested with external amplifier and speaker, the external amplifier was able to detect the sound waves from microphone on speaker and oscilloscope. The maximum amplitude of output speech signal of amplifier is 45 mV, and the maximum output of MEMS microphone is 1.125 μV.     

Design and fabrication of a new MEMS capacitive microphone using a perforated aluminum diaphragm

In this paper, a novel single-chip MEMS capacitive microphone is presented. The novelties of the method relies on the moveable aluminum (Al) diaphragm positioned over the backplate electrode, where the diaphragm includes a plurality of holes to allow the air in the gap between the electrode and the diaphragm to escape and thus reducing acoustical damping in the microphone. Spin-on-glass (SOG) was used as a sacrificial and isolating layer. Backplate is monocrystalline silicon wafer, that it is more stiff. This work will focus on design, simulation, fabrication and characterization of the microphone. The structure has a diaphragm thickness of 3 μm, a diaphragm size of 0.5 mm × 0.5 mm, and an air gap of 1.0 μm. The results show that the pull-in voltage is 105 V, the initial stress of evaporated aluminum diaphragm is around 1500 MPa and the zero bias capacitance of microphone is 2.12 pF. Comparing with the previous works, this microphone has several advantages: the holes have been made on diaphragm, therefore no need of KOH etching to make back chamber, in this way the chip size of each microphone is reduced. The fabrication process uses minimal number of layers and masks to reduce the fabrication cost.     

Design, fabrication and testing of sandwich coupled inductors

A planar coupled inductor having sandwich coil structure is fabricated using MEMS microfabrication techniques. The structure of the inductor coil is designed to achieve high coupling and high winding number with a relatively small coil area. In this work, the structure is fabricated by bonding two planar on-chip coil fabricated on two different substrates. This method can replace the conventional via connections that cause various problems in output pads interconnection. The functionality of the fabricated device was tested, while the basic characteristics of the fabricated coil were measured at wide range of operating frequency using cascade GSG probe and compared with the simulation. For measurements up to 1?GHz, three resonance frequencies, inductance of 35?nH and resistance of as low as 25?Ω were observed. The results show that the proposed technique is a promising alternative method for fabricating a simple and cost effective 3-D coupled inductors.     

Impact of oxygen-permeable mold on fabrication of microchannels with ultraviolet curable materials

In this work, effect of oxygen diffusion on curing of materials which are sensitive to ultra violet light (UV) in fabrication of microchannels using micromolds with oxygen permeability is investigated. The effects of physical boundary conditions of mold on microfabrication of polymeric arrays of high aspect-ratio microchannels in presence of oxygen inhibition and under variable UV intensity and dose are studied analytically and experimentally. Polydimethylsiloxane (PDMS) as the oxygen-permeable material and polyurethane methacrylate (PUMA) as the UV-curable substrate are selected for experiments. It is shown that for a wide range of exposure intensity and dose, a thin layer of PUMA resin with thickness of a few micrometers in contact with the mold remains uncured and inhibited by high concentration of oxygen molecules while the overall curing rate is reduced by about tenfold for PDMS compared to impermeable silicon mold. The direct impact of presence of high concentration of oxygen in both of mold and resin during UV curing and due to insufficient exposure dose and intensity is a considerable alteration in geometries of manufactured microstructures. The obtained results are crucial for method of use of micromolding and evaluation of fidelity of the replicated microstructures with the proposed design in terms of verticality of the walls and details of the transferring patterns that are important to microfluidic applications.

     

Tunable Spectrum Selectivity for Multiphoton Absorption with Enhanced Visible Light Trapping in ZnO Nanorods

Observation of visible light trapping in zinc oxide (ZnO) nanorods (NRs) correlated to the optical and photoelectrochemical properties is reported. In this study, ZnO NR diameter and c‐axis length respond primarily at two different regions, UV and visible light, respectively. ZnO NR diameter exhibits UV absorption where large ZnO NR diameter area increases light absorption ability leading to high efficient electron–hole pair separation. On the other hand, ZnO NR c‐axis length has a dominant effect in visible light resulting from a multiphoton absorption mechanism due to light reflection and trapping behavior in the free space between adjacent ZnO NRs. Furthermore, oxygen vacancies and defects in ZnO NRs are associated with the broad visible emission band of different energy levels also highlighting the possibility of the multiphoton absorption mechanism. It is demonstrated that the minimum average of ZnO NR c‐axis length must satisfy the linear regression model of Z _p,min = 6.31d to initiate the multiphoton absorption mechanism under visible light. This work indicates the broadening of absorption spectrum from UV to visible light region by incorporating a controllable diameter and c‐axis length on vertically aligned ZnO NRs, which is important in optimizing the design and functionality of electronic devices based on light absorption mechanism.     

Enhanced electromagnetic transmission through a slit surrounded by rectangular grooves

Electromagnetic transmission through a slit surrounded by rectangular grooves in a conducting plane is investigated. An electromagnetic boundary-value problem associated with a slit surrounded by rectangular grooves in a conducting plane is rigorously solved based on the Fourier transform, eigenfunction expansion and mode matching method. The transmission coefficient through the slit is represented in a series. Computation is performed to illustrate the effect of the groove geometry on the transmission behaviours.     

Analyzing CT images for detecting lung cancer by applying the computational intelligence-based optimization techniques

Lung cancer is the most critical disease because it affects both men and women. Most of the time, lung cancer leads to death due to less health care and medical attention. In addition, lung cancer is difficult to identify in earlier stages due to the low-level symptoms and risk factors. To overcome the complexity, effective techniques must predict lung cancer earlier. To attain the problem statement, an lung cancer identification system is developed with the help of a meta-heuristic algorithm. The CT imageries obtained from the CIA database are analyzed step by step. The gathered image noise is removed by applying the mean filter, and the affected regions are segmented with the help of the Butterfly Optimization Algorithm-based K-Means Clustering (BOAKMC) algorithm. Afterward, various statistical features are derived, and the Supervised Jaya Optimized Rough Set related Feature Selection (SJORSFS) process is used to select the lung features. Finally, the lung cancer is identified using Autoencoder based Recurrent Neural Network (ARNN) classification algorithm, successfully recognizing the lung cancer features. Then the system's efficiency is evaluated using a MATLAB setup; here, 3000 are treated as training images and 2043 for testing images. The effective training enhances overall lung cancer prediction accuracy by up to 99.15%.