Multimedia Tools and Applications - Many vision-based human-computer interaction (HCI) applications require skin detection. However, their performance relies on accuracy in detecting skin regions... 相似文献
The effective visualization of vascular structures is critical for diagnosis, surgical planning as well as treatment evaluation. In recent work, we have developed an algorithm for vessel detection that examines the intensity profile around each voxel in an angiographic image and determines the likelihood that any given voxel belongs to a vessel; we term this the "vesselness coefficient" of the voxel. Our results show that our algorithm works particularly well for visualizing branch points in vessels. Compared to standard Hessian based techniques, which are fine-tuned to identify long cylindrical structures, our technique identifies branches and connections with other vessels. Using our computed vesselness coefficient, we explore a set of techniques for visualizing vasculature. Visualizing vessels is particularly challenging because not only is their position in space important for clinicians but it is also important to be able to resolve their spatial relationship. We applied visualization techniques that provide shape cues as well as depth cues to allow the viewer to differentiate between vessels that are closer from those that are farther. We use our computed vesselness coefficient to effectively visualize vasculature in both clinical neurovascular x-ray computed tomography based angiography images, as well as images from three different animal studies. We conducted a formal user evaluation of our visualization techniques with the help of radiologists, surgeons, and other expert users. Results indicate that experts preferred distance color blending and tone shading for conveying depth over standard visualization techniques. 相似文献
Historical data based fault diagnosis methods exploit two key strengths of multivariate statistical approaches, viz.: (i) data compression ability, and (ii) discriminatory ability. It has been shown that correspondence analysis (CA) is superior to principal components analysis (PCA) on both these counts (Detroja, Gudi, Patwardhan, & Roy, 2006a), and hence is more suited for the task of fault detection and isolation (FDI). In this paper, we propose a CA based methodology for fault diagnosis that can facilitate significant data reduction as well as better discrimination. The proposed methodology is based on the principle of distributional equivalence (PDE). The PDE is a property unique to the CA algorithm and can be very useful in analyzing large datasets. The principle, when applied to historical data sets for FDI, can significantly reduce the data matrix size without significantly affecting the discriminatory ability of the CA algorithm. This can significantly reduce computational load during statistical model building. The data reduction ability of the proposed methodology is demonstrated using a simulation case study involving benchmark quadruple tank laboratory process. The proposed methodology when applied to experimental data obtained from the quadruple tank process also demonstrated data reduction capabilities of the principle of distributional equivalence. The above aspect has also been validated for large-scale data sets using the benchmark Tennessee Eastman process simulation case study. 相似文献
A new inorganic–organic POM-based hybrid material comprising Keggin type mono manganese substituted phosphotungstate and enantiopure S-(+)-sec-butyl amine was synthesized in an aqueous media by simple ligand substitution method. The synthesized hybrid material was systematically characterized in solid as well as solution by various physicochemical techniques such as elemental analysis, TGA, UV–vis, FT-IR, ESR and multinuclear solution NMR (31P, 1H, 13C). The presence of chirality in the synthesized material was confirmed by CD spectroscopy and polarimeter. The above study reveals the attachment of S-(+)-sec-butyl amine to Keggin type mono manganese substituted phosphotungstate through N → Mn bond. It also indicates the retainment of Keggin unit and presence of chirality in the synthesized material. An attempt was made to use the synthesized material as a heterogeneous catalyst for carrying out aerobic asymmetric oxidation of styrene using molecular oxygen. The catalyst shows the potential of being used as a stable recyclable catalytic material after simple regeneration without significant loss in conversion. 相似文献
Uniform spherical chitosan particles of size <10 μm in diameter are important in drug delivery applications due to their excellent
biocompability and biodegradability. A high concentration of chitosan in the particles can help to control the release of
drugs and methods for processing high viscosity chitosan solutions are therefore required. In principle, any type of polymer,
whether hydrophobic or hydrophilic, can be electrosprayed to obtain monodisperse particles of diameter <10 μm. In practice,
however, electrospraying of biopolymers having viscosities of >100 mPa s results in particles >10 μm diameter. In this study,
by reducing surface tension of a high viscosity chitosan suspension, it was found that smaller diameter particles could be
prepared. Chitosan solutions were electrosprayed in the stable cone-jet mode to systematically study the relationship between
particle diameter, viscosity and surface tension. Increasing viscosity resulted in larger diameter particles with a broad
size distribution, but decreasing surface tension had the opposite effect. Results show that a chitosan solution having a
viscosity of ~80 mPa s can be used to prepare chitosan particles of diameter ~2.5 μm which on drying reduced to particles
of 500 nm. 相似文献
Production of protein and volatile fatty acids by anaerobic digestion of blackstrap molasses was investigated. This protein
may have potential as a feed for animals (and, we hope, for humans) in the near future. Volatile fatty acids can be further
fermented to produce methane. Fermentation of molasses byEubacterium ruminantium was studied in a chemostat at a constant temperature of 37 C. This study focused on kinetics of growth of the pure culture.
The maximum rate of protein production of about 0.326 g/l/hr was obtained when the pH and retention times were 6.2 and between
5 and 7 hrs, respectively. Average cell yield was 12.6% and carbohydrate conversion was 82 to 99%. Volatile fatty acids also
were produced, with acetic acid and n-butyric acid being the predominant products. Two different kinetic models were used
to fit the experimental data. The kinetic parameters obtained for the Monod model were: μmax=0.207 (1/hr); ks=0.165 g/l. 相似文献
The miniaturization of chemical and biological processes in microfluidic devices and bioarrays is a major technological achievement. Microchips performing multiphase material synthesis operations could be a future step in this trend of miniaturizing technology. Here we show how electrically controlled chips can be used for the synthesis and manipulation of new types of particles with advanced structure. The method is based on a technique that allows freely suspended droplets and particles to be entrapped and transported using electric fields. The fields that hold and guide the droplets and particles are applied through arrays of electrodes submerged in the oil. Each of the microdroplets suspended on the surface of fluorinated liquid serves as a microscopic reactor, where the particles are formed by solidification of the carrier droplets. Controlled on-chip assembly, drying, encapsulation and polymerization were used to make anisotropic 'eyeball' and striped particles, polymer capsules and semiconducting microbeads. 相似文献
In recent times, the majority of colour-based skin detection methods used skin modelling in different colour spaces, and they are capable of skin classification at a pixel level. However, the accuracy of these methods is significantly affected by different issues, such as the presence of skin-like colours in scene background, variations in skin pigmentation, scene illumination, etc. Recent developments show that the discriminating power of a colour-based skin classifier can be increased by employing texture and spatial features. However, we observed that discriminability between skin and non-skin regions does not follow any statistics, and the discrimination is extremely image specific. In this paper, a novel adaptive discriminative analysis (ADA) is proposed to extract most discriminant features between skin and non-skin regions from an image itself in an unsupervised manner. Experimental results for standard databases show that the proposed method can efficiently segment out skin pixels in the presence of skin-like background colours.