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The paper presents a real-time vision system to compute traffic parameters by analyzing monocular image sequences coming from pole-mounted video cameras at urban crossroads. The system uses a combination of segmentation and motion information to localize and track moving objects on the road plane, utilizing a robust background updating, and a feature-based tracking method. It is able to describe the path of each detected vehicle, to estimate its speed and to classify it into seven categories. The classification task relies on a model-based matching technique refined by a feature-based one for distinguishing between classes having similar models, like bicycles and motorcycles. The system is flexible with respect to the intersection geometry and the camera position. Experimental results demonstrate robust, real-time vehicle detection, tracking and classification over several hours of videos taken under different illumination conditions. The system is presently under trial in Trento, a 100,000-people town in northern Italy.  相似文献   
3.
An oxygen plasma treatment has been used to improve the adhesion of amorphous hydrogenated carbon (a‐C:H) films onto surfaces of recycled poly(ethylene terephthalate) (PET). Modifications produced by the oxygen plasma on the PET surface in chemical bonds and morphology were investigated by X‐ray photoelectron spectroscopy and atomic force microscopy, respectively. Contact angle measurements were used to study the changes in the surface wettability. Adhesion of the a‐C:H film onto the PET surface was investigated by the tape test method. It was observed that the improvement in film adhesion is in good correlation with the increase in surface roughness, due to plasma etching, and with the appearance of oxygen‐related functional groups at the surface. The results of this study indicate that a‐C:H‐coated recycled PET can be used in food packaging. The a‐C:H film could be used as a functional barrier to reduce or prevent migration of contaminants from the polymer to the package content. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010  相似文献   
4.
Quality criteria for an image received from optic-electronic complexes of space remote sensing systems and methods of evaluating these quality criteria that allow one to choose parameters of elements of a ground space information channel together with orbital design of space remote sensing systems are considered.  相似文献   
5.
The flotation behaviour of fine particles is studied in this work. Fine methylated quartz particles within the size range from 0.2 to 50 μm, and with varying contact angles, were floated in a mechanical flotation cell. Results indicate that particles of a given size need to possess a minimum critical contact angle, which increases in value as particle size decreases, for flotation to be initiated. As a consequence, a non-floating component exists within a given size fraction. This is interpreted as a fraction consisting of particles below the critical contact angle for flotation for that size. The critical contact angle for flotation is explained in terms of the existence of an energy barrier for bubble-particle attachment. The flotation results are interpreted by means of [Scheludko et al., 1976] and [Drelich and Miller, 1992] models for the floatability of fine particles. The experimental data compared very well with calculations using the Drelich and Miller equation, allowing extension to the prediction of the critical contact angle for flotation down to particle sizes well below the previous limits investigated, bridging the gap existing in the literature.  相似文献   
6.
In this work, high density polyethylene (HDPE) incorporation in virgin resin was assessed as to its electrical performance with the use of volumetric resistivity, dielectric strength, and stress tracking measurements. HDPE post-consumer packaging was collected and submitted to a basic process of plastic recovering: washing, grinding, and drying. Formulations containing 0, 25, 50, 75, and 100% of recycled material in the virgin resin were reprocessed by extrusion and injection molding with stabilization. Dielectric strength test results were analyzed by the statistical distribution of Weibull, and the maximum likelihood method. The degree of crystallinity was measured by X-ray diffraction. Atomic absorption spectroscopy was also done to identify metallic residue present in the samples. From the results analyzed, it can be concluded that the HDPE derived from post-consumer packaging can be considered in electrical insulation systems for low voltage (up to 600 V) containing as much as 75% incorporated virgin resin.  相似文献   
7.
The lattice constants of AlxGa1?x As epitaxial alloys with various AlAs (x) contents are determined for AlxGa1?xAs/GaAs(100) heterostructures grown by MOC-hydride epitaxy using X-ray diffractometry and an X-ray back-reflection method. An ordered AlGaAs2 (superstructural) phase is found in epitaxial heterostructures with x ≈ 0.50. The lattice constant of this phase is smaller than the lattice constants of an Al0.50Ga0.50As alloy and GaAs single-crystal substrate.  相似文献   
8.
This work focuses principally on the influence of time, temperature, and contact with food simulants in adhesion of amorphous hydrogenated carbon (a‐C:H) films obtained by the plasma enhanced chemical vapor deposition process in recycled PET from packaging. Shelf life of packaging used in soft drinks, fruit juice, etc. is known to be ~ 6 months, with possible variations. The a‐C:H film, used in this study as a functional barrier against possible contaminants in recycled PET, was analyzed to determine possible alterations in its physical and chemical properties. The film underwent an accelerated aging test and was exposed to contact with food simulants listed by the FDA. In this case, adhesion is one of the properties most in need of conservation. This property was analyzed by means of the tape test and scanning electronic microscopy. Superficial chemical alterations resulting from both the accelerated aging test and contact with liquids were examined by the contact angle. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009  相似文献   
9.
A model was developed to study the drying rate of biopolymer films. The diffusivity of water in this biopolymer film is an exponential function of the water concentration. This creates a situation where simply increasing gas velocity can decrease the actual drying rate. The model revealed that the main factor limiting the drying of the biopolymer film was a significant and rapid decrease in the diffusivity of water through the film as the film dried. To avoid this a pulsing scheme was proposed where the velocity of the drying gas would be varied during the experiment; this variation allowed for a compromise between a high overall drying rate and maintaining a high diffusivity within the film. It was found that the optimum combination of gas velocities was 0.8 and 0.6 m/s with a duration of 10 min at the high and low gas velocities.  相似文献   
10.
A GIS-based procedure for predicting pesticide exposure in surface waters has been applied on a pilot river basin characterized by intensive agricultural activity. The predictive approach has been validated through experimental monitoring, performed by collecting manual and automatic water samples during the productive season. Five active ingredients (terbuthylazine, metolachlor, alachlor, linuron, fenitrothion) were selected for analysis to validate the predictive approach. Comparison between predicted and experimental values showed good agreement for terbuthylazine and metolachlor (used in large volumes within the basin), demonstrating the reliability of the approach. However, some anomalous results were obtained for some of the other chemicals, which serve to highlight the difficulties in getting reliable input data, in particular on application patterns (rate and time). Furthermore, the value of mapping pesticide exposure on the medium-large scale is described, and the limitations of the reported predictive approach are discussed.  相似文献   
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