Direct, Dense, and Deformable:Template-Based Non-Rigid 3D Reconstruction from RGB Video

In this paper we tackle the problem of capturing the dense, detailed 3D geometry of generic, complex non-rigid meshes using a single RGB-only commodity video camera and a direct approach. While robust and even real-time solutions exist to this problem if the observed scene is static, for non-rigid dense shape capture current systems are typically restricted to the use of complex multi-camera rigs, take advantage of the additional depth channel available in RGB-D cameras, or deal with specific shapes such as faces or planar surfaces. In contrast, our method makes use of a single RGB video as input, it can capture the deformations of generic shapes, and the depth estimation is dense, per-pixel and direct. We first compute a dense 3D template of the shape of the object, using a short rigid sequence, and subsequently perform online reconstruction of the non-rigid mesh as it evolves over time. Our energy optimization approach minimizes a robust photometric cost that simultaneously estimates the temporal correspondences and 3D deformations with respect to the template mesh. In our experimental evaluation we show a range of qualitative results on novel datasets, we compare against an existing method that requires multi-frame optical flow, and perform a quantitative evaluation against other template-based approaches on a ground truth dataset

A regional thermohaline inverse method for estimating circulation and mixing in the Arctic and subpolar North Atlantic

A Regional Thermohaline Inverse Method (RTHIM) is presented that estimates velocities through the section bounding an enclosed domain and transformation rates due to interior mixing within the domain, given inputs of surface boundary fluxes of heat and salt and interior distributions of salinity and temperature. The method works by invoking a volumetric balance in thermohaline coordinates between the transformation due to mixing, surface fluxes and advection, while constraining the mixing to be down tracer gradients. The method is validated using a 20-year mean of outputs from the NEMO model in an Arctic and subpolar North Atlantic domain, bound to the south by a section with a mean latitude of 66°N. RTHIM solutions agree well with the NEMO model ‘truth’ and are robust to a range of parameters; the MOC, heat and freshwater transports calculated from an ensemble of RTHIM solutions are within 12%, 10% and 19%, respectively, of the NEMO values. There is also bulk agreement between RTHIM solution transformation rates due to mixing and those diagnosed from NEMO. Localized differences in diagnosed mixing may be used to guide the development of mixing parameterizations in models such as NEMO, whose downgradient diffusive closures with prescribed diffusivity may be considered oversimplified and too restrictive

The Keck Cosmic Web Imager: a capable new integral field spectrograph for the W. M. Keck Observatory

The Keck Cosmic Web Imager (KCWI) is a new facility instrument being developed for the W. M. Keck Observatory and funded for construction by the Telescope System Instrumentation Program (TSIP) of the National Science Foundation (NSF). KCWI is a bench-mounted spectrograph for the Keck II right Nasmyth focal station, providing integral field spectroscopy over a seeing-limited field up to 20"x33" in extent. Selectable Volume Phase Holographic (VPH) gratings provide high efficiency and spectral resolution in the range of 1000 to 20000. The dual-beam design of KCWI passed a Preliminary Design Review in summer 2011. The detailed design of the KCWI blue channel (350 to 700 nm) is now nearly complete, with the red channel (530 to 1050 nm) planned for a phased implementation contingent upon additional funding. KCWI builds on the experience of the Caltech team in implementing the Cosmic Web Imager (CWI), in operation since 2009 at Palomar Observatory. KCWI adds considerable flexibility to the CWI design, and will take full advantage of the excellent seeing and dark sky above Mauna Kea with a selectable nod-and-shuffle observing mode. In this paper, models of the expected KCWI sensitivity and background subtraction capability are presented, along with a detailed description of the instrument design. The KCWI team is lead by Caltech (project management, design and implementation) in partnership with the University of California at Santa Cruz (camera optical and mechanical design) and the W. M. Keck Observatory (program oversight and observatory interfaces)