Universal demosaicking for imaging pipelines with an RGB color filter array

A universal demosaicking solution appropriate for imaging pipelines employing a red-green-blue (RGB) color filter array (CFA) is introduced. The proposed solution can demosaick a raw, grayscale, CFA sensor image captured by a digital camera equipped with any RGB-CFA currently in use. The solution utilizes a spectral model, an edge-sensing mechanism, and a postprocessor to preserve the coloration and sharpness of the captured image. The framework readably unifies existing demosaicking solutions which differ in design characteristics, performance, and computational efficiency. Simulation studies indicate that the universal demosaicking framework allows for cost-effective camera image processing and produces visually pleasing full-color digital images.     

Secure single-sensor digital camera

An efficient secure single-sensor camera for captured image copyright protection and ownership authentication is introduced. Visible watermarks are embedded during the colour filter array (CFA) data acquisition process. Subsequent demosaicking of the watermarked CFA grey-scale images generates secure full-colour images readily available for storage or distribution.     

Suspensions Plasma Spraying of Ceramics with Hybrid Water-Stabilized Plasma Technology

Technology of water-stabilized plasma torch was recently substantially updated through introduction of a so-called hybrid concept that combines benefits of water stabilization and gas stabilization principles. The high-enthalpy plasma provided by the WSP-H (“hybrid”) torch may be used for thermal spraying of powders as well as liquid feedstocks with high feed rates. In this study, results from three selected experiments with suspension plasma spraying with WSP-H technology are presented. Possibility of deposition of coatings with controlled microstructures was demonstrated for three different ceramics (YSZ—yttria-stabilized zirconia, YAG—yttrium aluminum garnet and Al₂O₃) introduced into ethanol-based suspensions. Shadowgraphy was used for optimization of suspension injection and visualization of the liquid fragmentation in the plasma jet. Coatings were deposited onto substrates attached to the rotating carousel with integrated temperature monitoring and air cooling, which provided an excellent reproducibility of the deposition process. Deposition of columnar-like YSZ and dense YAG and Al₂O₃ coatings was successfully achieved. Deposition efficiency reached more than 50%, as evaluated according to EN ISO 17 836 standard.     

Controlling Microstructure of Yttria-Stabilized Zirconia Prepared from Suspensions and Solutions by Plasma Spraying with High Feed Rates

Introduction of suspension and solution plasma spraying led to a breakthrough in the deposition of yttria-stabilized zirconia (YSZ) coatings and enabled preparation of new types of layers. However, their deposition with high feed rates needed, for example, for the deposition of thermal barrier coatings (TBCs) on large-scale components, is still challenging. In this study, possibility of high-throughput plasma spraying of YSZ coatings is demonstrated for the latest generation of high-enthalpy hybrid water-stabilized plasma (WSP-H) torch technology. The results show that microstructure of the coatings prepared by WSP-H may be tailored for specific applications by the choice of deposition conditions, in particular formulation of the liquid feedstock. Porous and columnar coatings with low thermal conductivity (0.5-0.6 W/mK) were prepared from commercial ethanol-based suspension. Dense vertically cracked coatings with higher thermal conductivity but also higher internal cohesion were deposited from suspension containing ethanol/water mixture and coarser YSZ particles. Spraying of solution formulated from diluted zirconium acetate and yttrium nitrate hexahydrate led also to the successful deposition of YSZ coating combining regions of porous and denser microstructure and providing both low thermal conductivity and improved cohesion of the coating. Enthalpy content, liquid-plasma interaction and coating buildup mechanisms are also discussed.     

Potential for acrylamide formation in potatoes: data from the 2003 harvest

Reducing sugars, free amino acids, and the potential for acrylamide formation were determined in more than 50 potato samples from the 2003 harvest in Switzerland. The reducing sugar content strongly correlated with acrylamide, whereas no correlation was found between acrylamide and free asparagine or the pool of free amino acids. The reducing sugar contents and the acrylamide potentials were higher in most of the cultivars tested than in the samples from 2002. This was probably due to the hot and dry summer of 2003. Monitoring sugars and amino acids during heating at 120 °C and 180 °C showed that glucose and fructose reacted much faster than sucrose and the amino acids. Glutamine was consumed to a larger extent than any of the other amino acids. During prolonged storage, the reducing sugars decreased considerably while only moderate changes in the free amino acids were observed. Altogether, glucose and fructose remain the critical factors for acrylamide formation in potatoes and represent the most feasible way of reducing the formation of acrylamide in potato products.     

Energy storage and heat deposition in flashlamp-pumped sensitizederbium glass lasers

Measurements of population inversion energy storage and heat deposition in flashlamp-pumped Nd:Yb:Er:glass and Cr:Nd:Yb:Er:glass lasers are reported. A thermal camera is used to measure temperature changes following isolated flashlamp pulses. A rate equation model is developed in order to determine energy storage from the output versus input energy characteristics of erbium lasers operating in a free-oscillation mode. Contributions of different sensitizers are distinguished by spectrally filtering flashlamp-pump radiation. Ratios of the deposited heat per unit stored energy in both glasses are compared for several spectral regions     

Development of EM field in lasers with rotating mirrorQ-switch

A fast-Fourier-transform (FFT) computational scheme based on a Fourier expansion technique is developed to calculate the development of an electromagnetic (EM) field from spontaneous noise inside a loaded rotating mirror Q-switched laser. A rate equations analysis is also carried out, using the FFT-calculated dependence of the diffraction loss on the fixed Q-switch mirror tilt angle. The computational results are compared with the output characteristics of an eye-safe (λ=1.54 μm) erbium glass laser. The experiments are in good qualitative and quantitative agreement with the predictions of the FFT mode. The model reveals short-duration intense spatial regions, as well as two types of temporal modulations of the laser output pulses. These modulations are attributed to the inhomogeneous development of the laser field in the longitudinal and transverse laser resonator direction. These irregularities must be taken into account when calculating eye-safety levels of rotating mirror Q-switched lasers     

Failure analysis of thermally cycled columnar thermal barrier coatings produced by high-velocity-air fuel and axial-suspension-plasma spraying: A design perspective

Axial-suspension-plasma spraying (ASPS) is a fairly recent thermal spray technology which enables production of ceramic top coats in TBCs, incorporating simultaneously the properties of both the conventional-plasma sprayed (highly insulating porous structures) and electron-beam-physical-vapor-deposited (strain-tolerant columnar structures) top coats. TBCs are required to insulate the hot components in a gas turbine engine against high temperature and harsh operating conditions. Periodic heating and cooling of turbine engines during operation can create severe thermal cyclic fatigue conditions which can degrade the performance of these coatings eventually leading to the failure. An in-depth experimental investigation was performed to understand the failure behavior of columnar TBCs subjected to thermal cyclic fatigue (TCF) test at 1100?C. The study revealed that the TCF performance was influenced to an extent, by the top coat microstructure, but was primarily affected by the severity of thermally grown oxide (TGO) growth at the bond coat-top coat interface. Mixed failure modes comprising crack propagation through the bond coat-TGO interface, through TGO and within the top coat were identified. Based on the analysis of the experimental results and thorough discussion a novel design of microstructure for the high TCF performance columnar TBC is proposed.