360-degree Video Stitching for Dual-fisheye Lens Cameras Based On Rigid Moving Least Squares

Dual-fisheye lens cameras are becoming popular for 360-degree video capture, especially for User-generated content (UGC), since they are affordable and portable. Images generated by the dual-fisheye cameras have limited overlap and hence require non-conventional stitching techniques to produce high-quality 360x180-degree panoramas. This paper introduces a novel method to align these images using interpolation grids based on rigid moving least squares. Furthermore, jitter is the critical issue arising when one applies the image-based stitching algorithms to video. It stems from the unconstrained movement of stitching boundary from one frame to another. Therefore, we also propose a new algorithm to maintain the temporal coherence of stitching boundary to provide jitter-free 360-degree videos. Results show that the method proposed in this paper can produce higher quality stitched images and videos than prior work.Comment: Preprint versio

Sulfidation Kinetics of Silver Nanoparticles Reacted with Metal Sulfides

Recent studies have documented that the sulfidation of silver nanoparticles (Ag-NP), possibly released to the environment from consumer products, occurs in anoxic zones of urban wastewater systems and that sulfidized Ag-NP exhibit dramatically reduced toxic effects. However, whether Ag-NP sulfidation also occurs under oxic conditions in the absence of bisulfide has not been addressed, yet. In this study we, therefore, investigated whether metal sulfides that are more resistant toward oxidation than free sulfide, could enable the sulfidation of Ag-NP under oxic conditions.We reacted citrate-stabilized Ag-NP of different sizes (10–100 nm) with freshly precipitated and crystalline CuS and ZnS in oxygenated aqueous suspensions at pH 7.5. The extent of Ag-NP sulfidation was derived from the increase in dissolved Cu²⁺ or Zn²⁺ over time and linked with results from X-ray absorption spectroscopy (XAS) analysis of selected samples. The sulfidation of Ag-NP followed pseudo first-order kinetics, with rate coefficients increasing with decreasing Ag-NP diameter and increasing metal sulfide concentration and depending on the type (CuS and ZnS) and crystallinity of the reacting metal sulfide. Results from analytical electron microscopy revealed the formation of complex sulfidation patterns that seemed to follow preexisting subgrain boundaries in the pristine Ag-NP. The kinetics of Ag-NP sulfidation observed in this study in combination with reported ZnS and CuS concentrations and predicted Ag-NP concentrations in wastewater and urban surface waters indicate that even under oxic conditions and in the absence of free sulfide, Ag-NP can be transformed into Ag₂S within a few hours to days by reaction with metal sulfides

Formation of Chlorination Byproducts and Their Emission Pathways in Chlorine Mediated Electro-Oxidation of Urine on Active and Nonactive Type Anodes

Chlorination byproducts (CBPs) are harmful to human health and the environment. Their formation in chlorine mediated electro-oxidation is a concern for electrochemical urine treatment. We investigated the formation of chlorate, perchlorate, and organic chlorination byproducts (OCBPs) during galvanostatic (10, 15, 20 mA·cm^–2) electro-oxidation of urine on boron-doped diamond (BDD) and thermally decomposed iridium oxide film (TDIROF) anodes. In the beginning of the batch experiments, the production of perchlorate was prevented by competing active chlorine and chlorate formation as well as by direct oxidation of organic substances. Perchlorate was only formed at higher specific charges (>17 Ah·L^–1 on BDD and >29 Ah·L^–1 on TDIROF) resulting in chlorate and perchlorate being the dominant CBPs (>90% of initial chloride). BDD produced mainly short chained OCBPs (dichloromethane, trichloromethane, and tetrachloromethane), whereas longer chained OCBPs (1,2-dichloropropane and 1,2-dichloroethane) were more frequently found on TDIROF. The OCBPs were primarily eliminated by electrochemical stripping: On BDD, this pathway accounted for 40% (dichloromethane) to 100% (tetrachloromethane) and on TDIROF for 90% (1,2-dichloroethane) to 100% (trichloromethane) of what was produced. A post-treatment of the liquid as well as the gas phase should be foreseen if CBP formation cannot be prevented by eliminating chloride or organic substances in a pretreatment

Schematic of biofilm detachment mechanisms during BaSO₄ injection.

<p>Schematic of biofilm detachment mechanisms during BaSO₄ injection.</p

Three-dimensional renderings of the solid phase (left), of the sample imaged with FeSO₄ (center) and barium suflate (right) as a contrast-enhancing agents.

<p>Three-dimensional renderings of the solid phase (left), of the sample imaged with FeSO₄ (center) and barium suflate (right) as a contrast-enhancing agents.</p

Information relative to the different scans and datasets used in this work as well as the corresponding details concerning the data analysis.

<p>Information relative to the different scans and datasets used in this work as well as the corresponding details concerning the data analysis.</p

Evaluation of the presented method and another existing one for imaging biofilms in porous media.

<p>Evaluation of the presented method and another existing one for imaging biofilms in porous media.</p

Conditioned probabilities that a given phase in the FeSO4 data locally belongs to the same phase in the BaSO4 data computed for the solid (S), liquid (L) and biofilm (BF) phases for the registered Lorentz filtered FeSO₄ and BaSO₄ datasets.

<p>Conditioned probabilities that a given phase in the FeSO4 data locally belongs to the same phase in the BaSO4 data computed for the solid (S), liquid (L) and biofilm (BF) phases for the registered Lorentz filtered FeSO₄ and BaSO₄ datasets.</p

Evolution of the permeate flux.

<p>The flux is shown in L m⁻² h⁻¹ for the filtration of differently treated feed water sources (LMA, DMA, and CON according to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0111794#pone-0111794-g001" target="_blank">Figure 1</a>). The two replicates per system are shown as circles and triangles, and are connected by the mean.</p

Middle slices (filtered prior to segmentation according information in Table 1) for the <i>LFeSO</i>₄ (A) and <i>BaSO</i>₄ (B) datasets.

<p>The corresponding 8 bit gray value histograms are shown in C) for the <i>BaSO</i>₄ (blue) dataset and for the <i>LFeSO</i>₄ (red) dataset after contrast enhancement and application of the 3D curvature-driven diffusive filter. For the <i>LFeSO</i>₄ dataset, the vertical dashed lines in yellow, purple and green correspond to isosurface values of 64, 73 and 82 used for the segmentation and the corresponding sensitivity analysis. The peaks corresponding to the different phases are annotated. (D) and (E) show the segmented datasets where the solid, liquid and biofilm phases are color coded in white, blue and green respectively. The scale bar represents 1 mm.</p