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CdS–ZnS layered thin films have been fabricated with using ZnS/glass layer prepared by chemical bath deposition as the seed, followed by deposition and crystallization of CdS thin films on its surface by hydrothermal reaction. X-ray diffraction, Ultraviolet–Visible absorption spectroscopy, Scanning Electron Microscopy, Transmission Electron Microscopy, and Confocal Raman spectroscopy were used to characterize the thin films. It was found that through adjusting the hydrothermal reaction condition, the thickness, crystal size, and optical properties of the CdS–ZnS heterostructure films can be finely controlled.

The undoped TiO 2 and Nd 3+ -doped TiO 2 samples were prepared by the sol–gel method and characterized by X-ray diffraction, diffuse reflectance UV-visible spectroscopy, transmission electron microscopy, and N 2 adsorption. The correlation of the photocatalytic activity for hydrogen evolution with the phase composition, BET surface area, and light absorption intensity in the UV region was investigated. For the undoped TiO 2 sample, the particle size and agglomeration increased while the BET surface area and the light absorption intensity in the UV region decreased with increasing calcination temperature. The anatase to rutile phase transformation started at 600°C and completed at 800°C. The photocatalytic activity of undoped TiO 2 decreased with increasing calcination temperature, and the sample calcined at 600°C was the best because of the coexistence of a certain proportion of rutile/anatase mixed phase. For the Nd 3+ /TiO 2 samples, Nd 3+ doping inhibited the crystal phase transformation and the rutile phase appeared at 800°C. Moreover, Nd 3+ doping restrained the growth of grain size, improved the dispersivity of the particles, and raised BET surface area. The more the doping amount, the larger the BET surface area. As the calcination temperature increased, the decreasing extent of the light absorption intensity of Nd 3+ /TiO 2 in the UV region was lower than that of undoped TiO 2 . Nd 3+ doping raised the photocatalytic activity for hydrogen generation, and the optimum amount of Nd 3+ doping was 0.1%, at which the photocatalytic activity of Nd 3+ /TiO 2 was 3.5 times that of undoped TiO 2 .

Sulfur-substituted In(OH)(3) [hereafter denoted as In(OH)(y)S-z] and Zn-doped In(OH)(y)S-z [hereafter denoted as In(OH)(y)S-z:Zn] are synthesized in an aqueous Solution of ethylenediamine via the hydrothermal method. The photoactivities of these catalysts for H,) production are investigated in the presence of Na2S and Na2SO3 sacrificial reagent under visible light illumination (lambda > 420 nm). The absorption edge of In(OH)(y)S-z shifted monotonically from 240 nm for In(OH)(3) to 570 nm for In(OH)(y)S-z when the atomic ratio of S/In in the synthesis solution is increased from 0 to 2.0. But the absorption edge of In(OH)(y)S-z:Zn shifted from 570 to 470 nm as the atomic ratio of Zn/In in the synthesis solution was increased from 0 to 1.0. The catalyst In(OH)(y)S-z is active for H-2 production, with an average rate of H-2 of 0.9-1.8 mu mol/h, under visible light illumination. The The rate of H-2 production is 35.8 and 67 mu mol/h on 2wt% Pt-loaded In(OH)(y)S-z:Zn photoactivity of In(OH)(y)S-z is enhanced by doping with Zn2+ catalyst when X = 0.2 and 0.5, respectively, corresponding to a quantum efficiency of 0.32 and 0.59% at 420 +/- 10 nm, respectively. (c) 2005 Elsevier Inc. All rights reserved.

Driven by the wide usage of smart devices today, gesture control with normal cameras is in great need to be studied further, especially in healthcare sector, for example, patient monitoring and rehabilitation. This paper proposes a practical hand tracking method to tackle the related challenges including efficiency and robustness. Based on an efficient framework which integrates segmentation and tracking, several enhancements are proposed for a robust hand chasing. Experiments on both PC and android smartphones prove the proposed method is efficient and robust.

An antimony germanate (Sb 2 Ge 3 O 9 ) was synthesized under mild solvothermal condition. Organic amine did not incorporate into the structure, although they are used and necessary in synthesis. The structure of this compound can be described as antimony germanate layers constructed from vertex-sharing GeO 4 tetrahedra and SbO 3 trigonal pyramid. The linkage of 3-rings and 9-rings forms an infinite sheet in crystallographic ab plane. The layer stacking together with only van der Waals force between layers. This work open possibilities for synthesizing other antimony germanate with novel structure topologies, since polyhedra such as [SbX 3 ], [SbX 4 ], [SbX 5 ] and [SbX 6 ] (X=O or F) can be formed.

Chemical vapor deposition growth of 1T' ReS2x Se2(1-x) alloy monolayers is reported for the first time. The composition and the corresponding bandgap of the alloy can be continuously tuned from ReSe2 (1.32 eV) to ReS2 (1.62 eV) by precisely controlling the growth conditions. Atomic-resolution scanning transmission electron microscopy reveals an interesting local atomic distribution in ReS2x Se2(1-x) alloy, where S and Se atoms are selectively occupied at different X sites in each Re-X6 octahedral unit cell with perfect matching between their atomic radius and space size of each X site. This structure is much attractive as it can induce the generation of highly desired localized electronic states in the 2D surface. The carrier type, threshold voltage, and carrier mobility of the alloy-based field effect transistors can be systematically modulated by tuning the alloy composition. Especially, for the first time the fully tunable conductivity of ReS2x Se2(1-x) alloys from n-type to bipolar and p-type is realized. Owing to the 1T' structure of ReS2x Se2(1-x) alloys, they exhibit strong anisotropic optical, electrical, and photoelectric properties. The controllable growth of monolayer ReS2x Se2(1-x) alloy with tunable bandgaps and electrical properties as well as superior anisotropic feature provides the feasibility for designing multifunctional 2D optoelectronic devices.

This paper describes a novel two-stage scheme for false alarm suppression on fast face detection which is mainly applied on real-time video applications, such as surveillance systems. The new scheme consists of the well-known Viola-Jones framework and face verifier based on eigenfaces for fast face detection while suppressing the false alarm to extremely low. The proposed scheme can be benefited from fusion of both local and global features. Experimental results show that our proposed method is able to overcome the inherent limitation of the Viola-Jones face detector without any compromise in speed.

Anatase TiO2, hexagonal Nd2O3, amorphous SiO2 and Al2O3 with macroporous or hollow sphere structures have been fabricated by employing periodically macroporous active carbon as a template; the final morphology of the oxides can be controlled by the number of infiltration steps and the addition of solvent to the precursor.

A new implicit polynomial (IP) fitting method is presented. It provides a different way of viewing the IP fitting problem from those of the nonlinear optimization approaches. It requires less computation, and can be done automatically or interactively. Linear programming is used to do the fitting. The approach can incorporate a variety of distance measures and global geometric constraints.

Query By Sketch for indexing into an image database involves presenting the machine with a sketch of the object to be found in the database. The sketch can be of the object shape or distinct contours on the image of the object. This sketch can be made from memory, or can be refined interactively in response to what the database search returns at each iteration. Or the sketch can be made by generating curves of an object boundary or object-surface image-discontinuities from an example image. This paper introduces and describes a family of 2D curves (implicit polynomial curves) for this purpose, and an algorithm for generating a representation which passes within e of a set of control points specified by the user. Control points can be placed at arbitrary locations and in arbitrary order, and can be erased by the user at will, in order to arrive at the desired shape representation. Level sets of the object potential field have been used to facilitate the interaction process. The fitting algorithm is formulated in the efficient Linear Programming (LP) framework. We illustrate the use of this method in the application of content-based image retrieval.

The LaTaON 2 catalyst with a perovskite structure has been successfully prepared by a high-temperature ammonolysis technique using NH 4 Cl as the mineralizer. The optical absorption edge of LaTaON 2 is significantly red-shifted compared with that of LaTaO 4 . Under visible light irradiation, LaTaON 2 with Pt or Ru as a co-catalyst shows high activity for reduction of water to H 2 in the presence of ethanol as a sacrificial electron reagent. A remarkable improvement in production efficiency was observed when both Pt and Ru were present.

Streaming layered video over peer-to-peer (P2P) networks has been recognized as an efficient way to address the receiver heterogeneity problem. The distinctive characteristics of layer encoded video also introduce complexities to data scheduling. In this paper, we propose a new data scheduling algorithm for layered P2P video-on-demand (VoD) streaming networks. Our algorithm consists of two parts: 1) layer adaptation, where peers adaptively adjust the number of subscribed layers to ensure a continuous playback of the highest possible video quality; and 2) piece selection, in which a peer selects a missing data piece to request based on its utility. The piece utility is calculated based on the playback constraint and the layer dependency of a piece. Through extensive packet-level simulations we show that our proposed data scheduling algorithm can effectively enhance the video playback quality.

A high-performance supercapacitor electrode consisting of platelet ordered mesoporous carbon CMK-5 and polyaniline (PANi) was prepared by chemical oxidative polymerization of aniline in the presence of CMK-5. The PANi with uniform size of 2-5 nm was primarily confined in the mesochannels of CMK-5 at low PANi loadings (40 and 51 wt %), whereas at a high loading of 64 wt %, additional PANi thin films with thicknesses of 5-10 nm were coated on the surface of the CMK-5 particles. Such CMK-5-PANi composites afforded a high electrochemical active surface area for surface Faradic redox reactions, leading to a more than 50% utilization efficiency when considering the theoretical capacitance of PANi of about 2000 F/g. As a result, a specific capacitance of 803 F/g and an energy density of 27.4 Wh/kg were achieved for CMK-5-PANi composite electrode with 64 wt % PANi, showing substantial improvement as compared with symmetric capacitors configured with CMK-5 electrodes (10.1 Wh/kg) or pure PANi electrodes (16.4 Wh/kg). Moreover, an excellent rate capability and a substantially enhanced electrochemical stability with 81% capacitance retention as compared with 68% of pure PANi were also observed over 1000 charge-discharge cycles at a constant current density of 4.0 A/g.

H. Xu, J. Zhang, and co-workers synthesize anisotropic 2D-layered rhenium disulfide with high crystal quality and uniform monolayer thickness. As described on page 5019, tellurium-assisted epitaxial growth on a mica substrate is chosen to generate such structures.

When peer-to-peer (P2P) networks meet social networks (for instance, Facebook), the former develops new characteristics. A notable change is that peers would use real names in social networks, and hence the P2P networks become naturally clustered according to the human relationship imported from the social networks. Conceivably, social network theories can be applied to improve the performance of P2P networks. This chapter introduces the social network theories, including small world (six degrees of separation), weak ties, structural holes, and others, and their applications in P2P networks. Specifically, the chapter describes applications of social networks in P2P networks using network coding as well as social networks in P2P content-centric networking (CCN) or named data networking (NDN), which is a brand-new framework for future communications.

Global warming and the finite nature of fossil fuels have driven the world to adopt sustainable and renewable energies. Electrochemical energy conversion and storage systems are considered as such energy sources. As a bridge between high-power-output conventional capacitors and high-energy-density batteries, supercapacitors (also known as ultracapacitors or electrical double layer capacitors) are an ideal electrochemical energy-storage system, suitable for rapid storage and release of energy. In comparison with that of batteries, the energy density of supercapacitors is much lower. Therefore, improving the energy density without sacrificing the high power density of supercapacitors has been a key research direction in developing high-performance supercapacitor devices. The properties of the active electrode materials, including surface area, pore size, pore connectivity, electric conductivity, and surface chemistry, play a crucial role in determining the ultimate performance of the supercapacitor. This article presents an overview of literature data on supercapacitor electrode materials. With a brief description of the structure and energy-storage mechanism of supercapacitors, recent advancements in electrode materials including carbon-based materials (e.g., activated carbon, templated carbon, carbon nanotubes, graphene), transition-metal oxides, and conducting polymers are summarized and discussed.

In this paper, we study the impact of the image quality (hence, the video streaming bit-rate) and the chunk-level impairment (hence the playback discontinuity) on the perceptual assessment of the viewing experience of P2P layered video streaming services. Through subjective QoE experiments, we have obtained several interesting findings and useful insights. The results clearly reveal the tradeoffs between streaming bitrate (B) and discontinuity (D) on the MOS under ceratin network condition. It is also showed that B-D tradeoff pattern is video content dependant. Based on these observations, a heuristic model is proposed to derive a group of MOS contours. This type of contours have practical usage and can help selecting suitable video streaming bit-rate (layer) for playback so as to maximize the perceptual QoE of the end users.

Ordered macroporous lanthanide oxides (Eu2O3, Nd2O3 and Sm2O3) have been fabricated using colloidal crystals of polystyrene (PS) spheres as a template in conjunction with the sol–gel method. Solidification of Ln3+–EDTA chelates in the voids between the PS spheres and removal of the template by calcination yields three-dimensional ordered macroporous oxides. X-Ray diffraction reveals that the phases of Eu2O3 , Nd2O3 and Sm2O3 are cubic, hexagonal and cubic, respectively, and scanning electron micrography shows that these oxides retain the structure of the initial template and exhibit 3D long-range ordered close packing of pores. The properties of these oxides are expected to allow them to find applications in areas including separation, catalysis and photonic crystals.

Three-dimensionally ordered macroporous active carbon has been fabricated by carbonizing an aqueous solution of sucrose in the presence of sulfuric acid; nitrogen adsorption measurements show the presence of a microporous wall structure framework leading to a high BET surface area of 408 m2 g−1.

A three-dimensional well-ordered network of macroporous CdS has been fabricated by a novel solvothermal synthesis route using SiO2 beads as a template; the CdS particles, which were introduced in the voids of the template and used as crystal seeds for the further growth of CdS from the liquid phase, were found to play a very important role in the formation of the final pore structure.

In this paper, we focus on the perceptual quality assessment of network streamed video via P2P networks. In these systems, the most noticeable impairments are not bit-level distortions, nor packet losses (as they get repaired), but video chunk or frame level delays. A key module in a video player is the video playback controller that decides whether to wait for delayed frames (hence freezing the playback), or try to playback by concealing the missing data. A good design should be based on how users react to different frame delay scenarios and playback decisions. We carefully designed a set of subjective tests to sample user reactions, and discuss how our results can be used in the design of playback controllers.

Ordered macroporous lanthanide oxides (Eu2O3, Nd2O3 and Sm2O3) have been fabricated using colloidal crystals of polystyrene (PS) spheres as a template in conjunction with the sol–gel method. Solidification of Ln3+–EDTA chelates in the voids between the PS spheres and removal of the template by calcination yields three-dimensional ordered macroporous oxides. X-Ray diffraction reveals that the phases of Eu2O3 , Nd2O3 and Sm2O3 are cubic, hexagonal and cubic, respectively, and scanning electron micrography shows that these oxides retain the structure of the initial template and exhibit 3D long-range ordered close packing of pores. The properties of these oxides are expected to allow them to find applications in areas including separation, catalysis and photonic crystals.

An antimony germanate (Sb 2 Ge 3 O 9 ) was synthesized under mild solvothermal condition. Organic amine did not incorporate into the structure, although they are used and necessary in synthesis. The structure of this compound can be described as antimony germanate layers constructed from vertex-sharing GeO 4 tetrahedra and SbO 3 trigonal pyramid. The linkage of 3-rings and 9-rings forms an infinite sheet in crystallographic ab plane. The layer stacking together with only van der Waals force between layers. This work open possibilities for synthesizing other antimony germanate with novel structure topologies, since polyhedra such as [SbX 3 ], [SbX 4 ], [SbX 5 ] and [SbX 6 ] (X=O or F) can be formed.

Highly-ordered three-dimensionally macroporous BaTiO3 is prepared by template-directed synthesis and is structurally characterized.

Spherical mesoporous carbons (SMC) were successfully synthesized by chemical vapor deposition (CVD) method using ferrocene as the carbon precursor and colloidal silica arrays as templates. The structure and textural properties of SMCs were characterized by a variety of techniques. Accordingly, a possible formation mechanism was proposed. These SMC materials were found to exhibit extraordinary high adsorption capacities (ca. 100 μmol/g) for lysozyme (Lz) in solution with a pH value of 11 close to its isoelectric point. The correlations between the textural parameters of SMCs with Lz adsorption capacity were also investigated along with discussion on its adsorption kinetics and stability.

Y(2)Ta(2)O(5)N(2) is presented as a novel photocatalyst with high activity for water splitting under visible-light irradiation in the presence of appropriate sacrificial reagents; the activity for reduction to H(2) is increased by the incorporation of Pt or Ru as a co-catalyst, with a significant increase in production efficiency when both Pt and Ru are present.

We present a novel application for Content Based Retrieval Techniques in Electronic Commerce using Interactive Multimedia, in which visual queries play a central role. We address some of the technical issues in representing and analysing image primitive features that are the building blocks of the MIRACLE system. These can be generalized into a much broader range of applications as well. We believe that Electronic Commerce is a very promising area with much potential for growth and that it covers a spectrum of rich research topics.

We present completely new very powerful solutions to two fundamental problems central to computer vision. Given data sets representing C objects to be stored in a database, and given a new data set for an object, determine the object in the database that is most like the object measured. We solve this problem through use of PIMs ("Polynomial Interpolated Measures"), which is a new representation integrating implicit polynomial curves and surfaces, explicit polynomials, and discrete data sets which may be sparse. The method provides high accuracy at low computational cost. 2. Given noisy 2D data along a curve (or 3D data along a surface), decompose the data into patches such that new data taken along affine transformations or Euclidean transformations of the curve (or surface) can be decomposed into corresponding patches. Then recognition of complex or partially occluded objects can be done in terms of invariantly determined patches. We briefly outline a low computational cost image-database indexing-system based on this representation for objects having complex shape-geometry.

Query By Sketch for indexing into an image database involves presenting the machine with a sketch of the object to be found in the database. The sketch can be of the object shape or distinct contours on the image of the object. This sketch can be made from memory, or can be refined interactively in response to what the database search returns at each iteration. Or the sketch can be made by generating curves of an object boundary or object-surface image-discontinuities from an example image. This paper introduces and describes a family of 2D curves for this purpose, and an algorithm for generating a representation which passes within E of a set of control points specified by the user. Control points can be placed at arbitrary locations and in arbitrary order, and can be erased by the user at will, in order to arrive at the desired shape representation. These curves can be applied in a number of ways: we illustrate their use in one approach to indexing.

In this paper, we developed a color model to cancel the dependency between color channels, which enables us to separate spectral processing from, spatial processing. We introduced Independent Component Analysis (ICA) transformation in the wavelet domain to decorrelate the subband color joint statistics. The decorrelated joint color conditional histograms display scaling of variance. Gaussian Scale Mixture (GSM) was used to model the subband color statistics and a normalization scheme was adapted to cancel the pair-wise color subband statistical dependency. This color model was combined with the Portilla/Simoncelli texture model to construct the color texture model. Based on this model, features were extracted and the corresponding color texture synthesis scheme was developed.

Video segmentation is a critical component for video shot detection, video data analysis and information retrieval. In this paper, a new statistical method for video segmentation based on the spatial and temporal analysis of the video data is proposed. A statistical hypothesis testing framework is described for video shot detection and video sequence segmentation. The proposed approach is based on the salient statistical features utilizing both local and global spatial and temporal information in the video image sequence. The statistical hypothesis testing framework in our approach provides a flexible way of handling the variabilities of the video data, and it avoids the pitfalls of heuristic methods of pre-defined threshold in traditional frame-difference and histogram based approaches. This algorithm is applied to real-time broadcasting news video and movie video clips. Experimental results indicate that the proposed algorithm is more robust than previous approaches. Significant performance improvements are observed and the efficacy of the algorithm is verified on the real unconstrained video sequence.

3D ordered macroporous multicomponent composite materials have been fabricated by electrochemical deposition of aniline on the inner surface of macroporous carbon; the maximum thickness of polyaniline (PANI) deposited is dependent on the concentration of the aniline as well as the dimension of the windows in the macroporous carbon.

In this paper we propose a novel system of semantic feature extraction and retrieval for interior design and decoration application. The system, V/sup 2/ID (virtual visual interior design), uses colored texture and spatial edge layout to obtain simple information about global room environment. We address the domain specific segmentation problem in our application and the techniques for obtaining semantic features from a room environment. We also discuss heuristics for making use of these features (color, texture or shape) to retrieve objects from an existing database. The final resynthesized room environment with original scene and novel object from database is created for the purpose of animation and virtual room walkthrough.

Multimedia information systems are experiencing a tremendous growth as a direct consequence of the popularity and pervasive use of the world wide web. As a consequence, it is becoming increasingly important to provide efficient and flexible solutions for accessing and retrieving multimedia data. Images and video are emerging as significant data types in multimedia systems. And yet, most commercial systems are still text and keyword based and do not fully exploit the image content of these systems. We believe that there is an opportunity to build a novel interactive multimedia system for some specific applications in electronic commerce. In this paper, we present an overview of our approach, the rationale behind it and the problems that are inherent in building such a system. We address some of the technical issues in representing and analyzing image primitive features. These are the building blocks of any such systems. They can be generalized into a much broader range of applications as well.

In this paper, we propose a novel system of semantic feature extraction and retrieval for interior design and decoration application. The system, V2ID(Virtual Visual Interior Design), uses colored texture and spatial edge layout to obtain simple information about global room environment. We address the domain-specific segmentation problem in our application and present techniques for obtaining semantic features from a room environment. We also discuss heuristics for making use of these features (color, texture, edge layout, and shape), to retrieve objects from an existing database. The final resynthesized room environment, with the original scene and objects from the database, is created for the purpose of animation and virtual walk-through.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

In this paper, we introduce a feature-based approach for image retrieval by sketch. Using edge segments as features which are modeled by implicit polynomials (IPs), we hope to provide a similarity computation method that is robust towards user query sketch distortions. We report some preliminary results of the first phase of our work in this paper. From these results, we could see that the feature-based method, which currently uses edge features modeled by first degree IPs, generally performs better than a pixel-based method that has been adopted by a number of well-known content-based image indexing and retrieval systems such as the IBM QBIC project. The feature-based method appears more robust and tolerant towards distortions in query sketches. We attribute this quality to the fact that it uses more structural information to compute the similarities between images. We will also describe a prototype built upon the Java technology that allows queries over the WWW. Finally we will discuss the promise and limitations of the feature-based method and conclude the paper with a look at areas for future work.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Implicit polynomials (IPs) are among the most effective representations for modeling and recognition of complex geometric shape structures because of their stability, robustness and invariant characteristics. In this paper, we describe an approach for geometric indexing into pictorial databases using IP representations. We discuss in detail a breakthrough in invariant decomposition of a complex object shape into manageable pieces or patches. The self and mutual invariants of those invariant patches can be then used as geometric indexing features vectors. The new concept of invariant signature curve for complex shapes ins developed that captures the semi-global algebraic structure of the object and has the advantage of being able to deal with multi-scale and object occlusion.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

A significant amount of text now present in World Wide Web documents is embedded in image data, and a large portion of it does not appear elsewhere at all. To make this information available, we need to develop techniques for recovering textual information from in-line Web images. In this paper, we describe two methods for Web image OCR. Recognizing text extracted from in-line Web images is difficult because characters in these images are often rendered at a low spatial resolution. Such images are typically considered to be 'low quality' by traditional OCR technologies. Our proposed methods utilize the information contained in the color bits to compensate for the loss of information due to low sampling resolution. The first method uses a polynomial surface fitting technique for object recognition. The second method is based on the traditional n-tuple technique. We collected a small set of character samples from Web documents and tested the two algorithms. Preliminary experimental results show that our n-tuple method works quite well. However, the surface fitting method performs rather poorly due to the coarseness and small number of color shades used in the text.

In this paper we present a geometry based indexing method for the semantic retrieval of large video databases. It combines two separate modules i.e., 3D object shape inferencing from a video sequence and geometric modeling from the reconstructed shape, to achieve better performance. First, a motion-based segmentation algorithm employing feature block tracking and hierarchical principal component split is used for multi-moving-object motion classification and segmentation. After segmentation, feature blocks for an individual moving scene or object can be used to reconstruct the 3D motion and shape structure of this scene or object by a factorization method. We assume object is rigid and relatively far away from the camera so that perspective distortion can be ignored. The estimated shape structure and motion parameters are then used to generate the implicit polynomial (IP) representation for the object. The system starts with a very coarse representation of the 3D shape. When more frames are available from the video stream and are properly segmented and classified, the IP representation will change accordingly by varying the coefficients of the implicit polynomial to minimize the estimation error. This process will stop when enough information is obtained to generate a reliable IP shape representation or until the video stream runs out. The semantic retrieval of the video databases is achieved by using the geometric structure of the objects and their spatial relationship. We generalize the 2D sting concept to 3D to compactly encode the spatial relationship among objects. The algebraic invariants of the implicit polynomial are used as the geometric feature vector for the object. A similarity value can be computed for two sets of objects or two video sequences to allow fast retrieval of video databases.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

In this paper we summarize our results and methods in modeling and representing free-form objects by implicit polynomials, and outline the application of this approach to the industrial inspection problem. Implicit polynomials have been widely used in the computer vision and graphics communities for many years with their flexibility, robustness and invariant features. The effectiveness of the use of this representation hinges upon two factors; the stability of the implicit polynomial fitting procedure and the segmentation of the object shape into manageable pieces. In much of the previous work, algebraic invariants of implicit polynomials have been used for estimation or recognition. In this paper, we propose a general multi-scale free-form object modeling and recognition framework where shape information at different scale is captured by different degree and size polynomials (patchlets). We also show that pose estimation and in turn object recognition can be done without using the algebraic invariants. To accomplish this a closed-form pose solution is obtained by comparing the corresponding patchlets. An overview of a free-form object recognition and inspection system built upon these results is given in the paper.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Denote a point in the plane by z=(z,y) and a polynomial of nth degree in z by f(z) /spl Sigma//sub i,j//spl ges/o/sub 1/i+j/spl les/n(a/sub ij/x/sup i/y/sup j/). Denote by Z(f) the set of points for which f(z)=0. Z(f) is the 2D curve represented by f(z). In this paper, we present a new approach to fitting 2D curves to data in the plane (or 3D surfaces to range data) which has significant advantages over presently known methods. It requires considerably less computation and the resulting curve can be forced to lie close to the data set at prescribed points provided that there is an nth degree polynomial that can reasonably approximate the data. Linear programming is used to do the fitting. The approach can incorporate a variety of distance measures and global geometric constraints.

β-MnO2 well-dispersed single crystals (average length ∼20 μm) with growth shape composed by bipyramid prism, are prepared by a F− anions-assisted hydrothermal method in a reaction system of Mn2+ and MnO4− at 180 °C for 36 h, and their formation process has been discussed. The as-prepared materials are characterized by XRD, SEM, TEM, XPS, and TG–DTA analyses, and their phase and morphology depend on the amount of F− anions, hydrothermal treatment temperature, and the hydrothermal treatment time. The F− anions play an important role in controlling the crystal phase and morphology of the obtained materials. A phase transformation change from the nanofiber α-MnO2 to tetragonal bipyramid, and finally, bipyramid prism β-MnO2 is observed with the increasing of the hydrothermal treatment time at 180 °C. The free F− anions in the reaction system are adsorbed preferentially on the {111} faces of the tetragonal bipyramid, which inhibits the growth rate of the [111] direction and favors growth of the {110} faces. The F− anions-assisted hydrothermal method can be potentially extended to prepare other metal oxides with particular crystallographic faces and novel morphologies.