21 research outputs found
Real-World Normal Map Capture for Nearly Flat Reflective Surfaces
Although specular objects have gained interest in recent
years, virtually no approaches exist for markerless reconstruction
of reflective scenes in the wild. In this work, we
present a practical approach to capturing normal maps in
real-world scenes using video only. We focus on nearly planar
surfaces such as windows, facades from glass or metal,
or frames, screens and other indoor objects and show how
normal maps of these can be obtained without the use of an
artificial calibration object. Rather, we track the reflections
of real-world straight lines, while moving with a hand-held
or vehicle-mounted camera in front of the object. In contrast
to error-prone local edge tracking, we obtain the reflections
by a robust, global segmentation technique of an
ortho-rectified 3D video cube that also naturally allows efficient
user interaction. Then, at each point of the reflective
surface, the resulting 2D-curve to 3D-line correspondence
provides a novel quadratic constraint on the local surface
normal. This allows to globally solve for the shape by integrability
and smoothness constraints and easily supports
the usage of multiple lines. We demonstrate the technique
on several objects and facades
Anaerobic granular sludge as a biocatalyst for 1,3-propanediol production from glycerol in continuous bioreactors
1,3-propanediol (1,3-PDO) was produced from glycerol in three parallel Expanded Granular Sludge Blanket (EGSB) reactors inoculated with granular sludge (control reactor-R1), heat-treated granular sludge (R2) and disrupted granular sludge (R3) at Hydraulic Retention Times (HRT) between 3 and 24 h. Maximum 1,3-PDO yield (0.52 mol mol-1) and productivity (57 g L-1 d-1) were achieved in R1 at HRTs of 12 h and 3 h, respectively. DGGE profiling of PCR-amplified 16S rRNA gene fragments showed that variations in the HRT had a critical impact in the dominant community of microorganisms. However, no appreciable differences in the bacterial population were observed between R2 and R3 at low HRTs. Production of H2 was observed at the beginning of the operation, but no methane production was observed. This study proves the feasibility of 1,3-PDO production in EGSB reactors and represents a novel strategy to valorise glycerol generated in the biodiesel industry.The financial support given to Roberto Gallardo from Fundacao da Ciencia e da Tecnologia (ref SFRH/BD/42900/2008) is gratefully acknowledged. The authors thank the MIT- Portugal Program for the support given to R. Gallardo and C. Faria