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The article presents a strategy for image segmentation by active contours. Results suggest the versatility and flexibility of the strategy for accommodating a diversity of image features for segmentation.

We address the problem of robust normal reconstruction by dense photometric stereo, in the presence of complex geometry, shadows, highlight, transparencies, variable attenuation in light intensities, and inaccurate estimation in light directions. The input is a dense set of noisy photometric images, conveniently captured by using a very simple set-up consisting of a digital video camera, a reflective mirror sphere, and a handheld spotlight. We formulate the dense photometric stereo problem as a Markov network and investigate two important inference algorithms for Markov Random Fields (MRFs)--graph cuts and belief propagation--to optimize for the most likely setting for each node in the network. In the graph cutalgorithm, the MRF formulation is translated into one of energy minimization. A discontinuity-preserving metric is introduced as the compatibility function, which allows [alpha]-expansion to efficiently perform the maximum a posteriori (MAP) estimation. Using the identical dense input and the same MRF formulation, our tensor belief propagation algorithm recovers faithful normal directions, preserves underlying discontinuities, improves the normal estimation from one of discrete to continuous, and drastically reduces the storage requirement and running time. Both algorithms produce comparable and very faithful normals for complex scenes. Although the discontinuity-preserving metric in graph cuts permits efficient inference of optimal discrete labels with a theoretical guarantee, our estimation algorithm using tensor belief propagation converges to comparable results, but runs faster because very compact messages are passed and combined. We present very encouraging results on normal reconstruction. A simple algorithm is proposed to reconstruct a surface from a normal map recovered by our method. With the reconstructed surface, an inverse process, known as relighting in computer graphics, is proposed to synthesize novel images of the given scene under user-specified light source and direction. The synthesis is made to run in real time by exploiting the state-of-the-art graphics processing unit (GPU). Our method offers many unique advantages over previous relighting methods and can handle a wide range of novel light sources and directions. Index Terms--Photometric stereo, Markov random fields, belief propagation, graph cuts, normal and surface reconstruction, robust inference, real-time relighting.

Abstract -- The main analytical characteristics of the reaction of hexaoxacycloazochrom with lead were determined. A method for the sorption preconcentration of lead on the Thiopan 14 sorbent was proposed. [...]

Abstract -- Complexes of scandium(III) with 2,2',3,4-tetrahydroxy-3'-sulfo-5'-nitroazobenzene were studied in the absence and presence of a third component, papaverine, dibazole, or urotropine. Optimal conditions for their formation were found, and [...]

Abstract -- Optical and colorimetric characteristics of 1-nitroso-2-naphthol-3,6-disulfonic acid (nitroso-R-salt) are studied in aqueous solutions at pH 4-10. Equations of calibration plots are obtained as the colorimetric functions of the [...]

Abstract -- A procedure for the photometric determination of mercaptan sulfur in light petroleum products was developed. This procedure is based on the formation of colored analytical species in an [...]

Scanning a document page from a thick bound volume often results in two kinds of distortions in the scanned image, i.e., shade along the "spine" of the book and warping in the shade area. In this paper, we propose an efficient restoration method based on the discovery of the 3D shape of a book surface from the shading information in a scanned document image. From a technical point of view, this shape from shading (SFS) problem in real-world environments is characterized by 1) a proximal and moving light source, 2) Lambertian reflection, 3) nonuniform albedo distribution, and 4) document skew. Taking all these factors into account, we first build practical models (consisting of a 3D geometric model and a 3D optical model) for the practical scanning conditions to reconstruct the 3D shape of the book surface. We next restore the scanned document image using this shape based on deshading and dewarping models. Finally, we evaluate the restoration results by comparing our estimated surface shape with the real shape as well as the OCR performance on original and restored document images. The results show that the geometric and photometric distortions are mostly removed and the OCR results are improved markedly. Index Terms--Document image restoration, document image analysis, shape from shading, image warping, image distortion, OCR improvement.

What is believed to be a novel phase-sensitive optical heterodyne interferometric ellipsometer is set up to characterize a twisted-nematic liquid crystal (TN-LC) by the elliptical parameters of the output polarization state. This ellipsometer presents the advantages of both polarized optical heterodyne interferometry and optical photometry, which introduce a polarization modulation that is capable of performing with high-sensitivity on phase detection in real time. The twist angle [phi] and the untwisted phase retardation [GAMMA] of TN-LC are measured precisely. The experimental results verify that a TN-LC can be treated as identical to an elliptical retarder. OCIS codes: 120.2130, 120.3180, 120.5240, 120.5410, 160.3710.

Byline: I. E. Kalinichenko (1), L. N. Demutskaya (1) Abstract: A method was proposed for determining nitrates in drinking water from the results of absorbance measurements at three wavelengths in the ultraviolet region of the absorption the nitrate ion. The determination limit depends on the water type and varies from 0.05 to 0.5 mg/L. A relatively simple equation was proposed for calculating nitrate concentrations. Author Affiliation: (1) Dumanskii Institute of Colloid and Water Chemistry, National Academy of Sciences of Ukraine, ul. Vernadskogo 42, Kiev, 03680, Ukraine Article History: Registration Date: 06/10/2004

Byline: Kh. A. Mirzaeva (1), M. S. Akhmedova (1), A. Sh. Ramazanov (1), S. A. Akhmedov (1) Abstract: The interactions of Dimedrol (Benadryl) and papaverine with Sulfonazo were studied by extraction--photometry. The formation of sparingly soluble associates that are readily extractable with butanol was found, and conditions for the formation and extraction of these associates were optimized. The composition and solvation numbers were found, and the mechanism of formation and the structure of the above ion associates were discussed. The kinetics of extraction was studied, and the recovery (96.5--97.5%) and distribution ratios (15.4 +- 0.5 and 13.8 +- 0.3 for Dimedrol and papaverine, respectively) were calculated. Procedures for the extraction--photometric determination of Dimedrol and papaverine were developed and applied to the analysis of pharmaceutical dosage forms. These procedures are characterized by adequate sensitivity, rapidity, and selectivity. Author Affiliation: (1) Department of Chemistry, Dagestan State University, ul. M. Gadzhieva 43a, Makhachkala, 367025, Russia Article History: Registration Date: 06/10/2004

Byline: V. P. Vasil'ev (1), A. V. Katrovtseva (1), A. I. Lytkin (1), N. V. Chernyavskaya (1) Abstract: The complexation of zirconium(IV) with Semimethylthymol Blue ([H.sub.4]L) was studied by spectrophotometry. The formation of the (ZrOH).sub.2([H.sub.2]L).sup.2+ .sub.2 complex with log[beta] = 20.68 +- 0.12 and [epsilon].sub.565 = (7.26 +- 0.02) x 10.sup.4 was revealed by the isomolar series and molar ratio methods. A simple, reliable, and sensitive method was developed for the photometric determination of zirconium. The calibration plot is linear in the concentration range of 10.sup.--6--10.sup.--5 M zirconium. In a sample of frit 24--70 containing 5.7% ZrO.sub.2, 5.44 +- 0.15% ZrO.sub.2 was found. Author Affiliation: (1) Ivanovo State University of Chemical Technology, pr. F. Engel'sa 7, Ivanovo, 153460, Russia Article History: Registration Date: 06/10/2004

Byline: Mir F. Mousavi (1), A. Rahmani (2), M. Barzegar (1), A. Jabbari (2) Abstract: A simple and sensitive catalytic-photometric method for the determination of trace amounts of palladium(II) based on its heterogeneous catalytic effect on the reduction of neutral red (NR) by hypophosphite (HP) has been developed. The reaction was monitored at 530 nm and the time elapsed (At) for the absorbance to decrease from its initial value by 1.5 absorbance units was recorded using the variable time method. The influence of reaction variables is discussed. The ranges of linearity were 0.108--6.533 ppm and 0.032--0.653 ppm palladium(II) at temperatures of 30 and 55degC, respectively. The relative standard deviations of the developed method were 2.5 and 2.7% (for 8 replicate determinations of 1.110 ppm Pd(II)) at 30 and 55degC, respectively. The effect of interferences from other metal ions and some anions was studied. The developed method has been successfully tested for determination of Pd(II) in Al--Si--Pd catalysts. Author Affiliation: (1) Department of Chemistry, Tarbiat Modarres University, P. O. Box: 14115-111, Tehran, Islamic Republic of Iran (2) Department of Chemistry, Hormozgan University, Bandar Abbas, Islamic Republic of Iran Article History: Registration Date: 06/10/2004

Abstract -- A procedure was developed for the flow-injection photometric determination of mercaptans in light oil products. The use of sodium nitroferricyanide as the photometric reagent at 540 nm provides [...]