Multi-Scale Blur Estimation and Edge Type Classification for Scene Analysis

Signatures, in this work, are multi-scale representations of local gray-level information, tied to places in gray scale images where regional differences are locally maximal. The information may involve the regional differences themselves (called Gaussian differences or signed normalized gradient magnitudes, (Korn, 1988)), or, distance relations between edges (apparent width measurements), or, absence of edges in pulse edge pairs, at coarser scales. Using signatures involves the classical problem mentioned by Marr and others of relating information across scales. A novel result is that a fruitful way of doing this is to build scale paths from coarse-to-fine exploiting edge focusing and associate with pixel positions, along these paths, the three quantities Gaussian differences, apparent width and the binary information absence/presence of edges (in edge-pairs). Such a structure, if used together with proper conditional tests, serves the purpose of classifying edges with respect to profile-type, and can also be used for measuring global contrast, degree of diffuseness, deblurred line width, and qualitative labels such as diffuse versus sharp. The structure is used simultaneously for labelling tasks and quantitative measurements. Theory on apparent widths, absence/presence of edges in pulse edge pairs is developed. For measuring diffuseness and global contrast from Gaussian difference signatures a linear least squares approach is suggested. Extensive experimental results are presented. Possible applications are in image segementation, junction analysis, and depth-from-defocus. For the purpose of distinguishing between objects and illumination phenomena, such as diffuse shadow edges, classification of contours with respect to diffuseness seems useful.     

Robust real-time tracking by fusing measurements from inertial and vision sensors

The problem of estimating and predicting position and orientation (pose) of a camera is approached by fusing measurements from inertial sensors (accelerometers and rate gyroscopes) and vision. The sensor fusion approach described in this contribution is based on non-linear filtering of these complementary sensors. This way, accurate and robust pose estimates are available for the primary purpose of augmented reality applications, but with the secondary effect of reducing computation time and improving the performance in vision processing. A real-time implementation of a multi-rate extended Kalman filter is described, using a dynamic model with 22 states, where 12.5 Hz correspondences from vision and 100 Hz inertial measurements are processed. An example where an industrial robot is used to move the sensor unit is presented. The advantage with this configuration is that it provides ground truth for the pose, allowing for objective performance evaluation. The results show that we obtain an absolute accuracy of 2 cm in position and 1° in orientation.     

Binding of vitronectin and clusterin by coagulase-negative staphylococci interfering with complement function

Coagulase-negative staphylococci (CoNS) are commonly associated with infections of prosthetic devices mediated by adsorbed host factors on biomaterial surfaces. Complement activation is known to occur and induce unspecific inflammation around the biomaterials. Human vitronectin (Vn) and clusterin (Clu), two potent inhibitors of complement, can be bound by CoNS. With a hypothesis whether binding of Vn or Clu influences complement activation, two measurements were determined. For Vn, complement activation was measured with a mouse anti-activated human C9 antibody. In the presence of Vn-binding strain, Staphylococcus hemolyticus SM13I, complement activation on a surface pre-coated with Vn occurred as it did in the absence of Vn pre-coating. For S. epidermidis 3380, which does not express binding of Vn, complement activation on a Vn-presented surface was significantly decreased. For Clu, erythrocytes lysis was measured to reflect the end product of complement activation (membrane attack complex). The complement-induced hemolysis increased when human serum was pre-incubated with Clu-binding strains, S. epidermidis J9P. The enhancement of hemolysis by J9P decreased when serum was supplemented by exogenous Clu. The data imply that interaction between CoNS and Vn or Clu interferes with one of their physiological functions, complement inhibition.     

Work functions shaping the ability to innovate: insights from the case of the safety engineer

Cognition, Technology & Work - To perform as intended, firms are divided into work functions that contribute to the behaviour-shaping constraints under which individuals build their skills,...     

Machinability and manufacturing cost in low-lead brass

Today, commercially used brasses commonly contain 2 to 4 wt% lead. As the availability of low-lead and lead-free brass increases, there are environmental incentives for investigating the consequences of replacing the lead-containing brasses with lead-free equivalents. Generally, lead-free brass is expected to have a lower machinability than its lead-alloyed counterpart, implying a higher manufacturing cost. Thus, the aim of this study has been to quantify the added manufacturing cost by replacing a standard brass alloy with a low-lead alternative. This was done through a case study performed at a Swedish SME which replaced CuZn39Pb3 (3.3 wt% Pb) with low-lead CuZn21Si3P (<?0.09 wt% lead) for a select part. Since CuZn21Si3P is almost twice as expensive as CuZn39Pb3, the material cost was found to have a substantial influence on the manufacturing cost. Additionally, the lower machinability implied a longer cycle time and higher losses while machining CuZn21Si3P, resulting in a 77% overall increase in manufacturing cost when using the low-lead material. Arguably, the difference in material cost, and thus manufacturing cost, may decrease over time making production of low-lead and lead-free brass products a viable option, especially when considering the environmental incentive for decreasing the amount of lead in circulation.     

Focusing properties of high charge number vortex laser beams

We investigate experimentally and numerically the propagation characteristics of laser beams formed by imparting an azimuthal phase lphi to a Gaussian beam, where l is an integer. We find that when high-l beams of a finite extent are focused through a lens, the beams achieve peak intensity and are most sharply defined before and after the focal plane. Additionally, in these regions of highest intensity the effect of aberrations on the beam quality is greatly reduced, which we also demonstrate experimentally and numerically. We present a simple geometrical picture that provides excellent estimates of the beam radius and propagation distance to the plane of peak intensity.     

Electron propagation along Cu nanowires supported on a Cu(111) surface

We present a joint experimental-theoretical study of the one-dimensional band of excited electronic states with sp character localized on Cu nanowires supported on a Cu(111) surface. Energy dispersion and lifetime of these states have been obtained, allowing the determination of the mean distance traveled by an excited electron along the nanowire before it escapes into the substrate. We show that a Cu nanowire supported on a Cu(111) surface can guide a one-dimensional electron flux over a short distance and thus can be considered as a possible component for nanoelectronics devices.     

The Fatty Acid 8,11-Diol Synthase of <Emphasis Type="Italic">Aspergillus fumigatus</Emphasis> is Inhibited by Imidazole Derivatives and Unrelated to PpoB

(8R)-Hydroperoxy-(9Z,12Z)-octadecadienoic acid (8-HPODE) is formed by aspergilli as an intermediate in biosynthesis of oxylipins with effects on sporulation. 8-HPODE is transformed by separate diol synthases to (5S,8R)-dihydroxy- and (8R,11S)-dihydroxy-(9Z,12Z)-octadecadienoic acids (5,8- and 8,11-DiHODE). The former is formed by the cytochrome P450 (P450) domain of 5,8-linoleate diol synthase (5,8-LDS or PpoA). Our aim was to characterize the 8,11-diol synthase of Aspergillus fumigatus, which is prominent in many strains. The 8,11-diol synthase was soluble and had a larger molecular size (>100 kDa) than most P450. Miconazole, ketoconazole, and 1-benzylimidazole, classical inhibitors of P450, reduced the biosynthesis of 8,11-DiHODE from 8-HPODE (apparent IC₅₀ values ~0.8, ~5, and ~0.6 μM, respectively), but did not inhibit the biosynthesis of 5,8-DiHODE. Analysis of hydroperoxides of regioisomeric C₁₈ and C₂₀ fatty acids showed that the 8,11-diol synthase was specific for certain hydroperoxides with R configuration. The suprafacial hydrogen abstraction and oxygen insertion at C-11 of 8-HPODE was associated with a small deuterium kinetic isotope effect (^H k _cat/^D k _cat ~1.5), consistent with P450-catalyzed oxidation. The genome of A. fumigatus contains over 70 P450 sequences. The reaction mechanism, size, and solubility of 8,11-diol synthase pointed to PpoB, a homologue of 5,8-LDS, as a possible candidate of this activity. Gene deletion of ppoB of A. fumigatus strains AF:?ku80 and J272 did not inhibit biosynthesis of 8,11-DiHODE and recombinant PpoB appeared to lack diol synthase activity. We conclude that 8,11-DiHODE is formed from 8-HPODE by a soluble and substrate-specific 8,11-diol synthase with catalytic characteristics of class III P450.