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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.

A microcountercurrent flame photometric detector [micro]cc-FPD) was adapted and optimized for ultrafast gas chromatographic (GC) separation and detection of organophosphor (OP) and organosulfur (OS) compounds on short chromatographic columns. Air and hydrogen are introduced to the [micro]cc-FPD from opposite directions, creating a hydrogen-rich flame. In this [micro]cc-FPD, combustion takes place between the burner tips without touching them. The separation between the tips and the flame reduces heat loss from the flame to the surrounding environment, resulting in low hydrogen consumption and a compact flame. The [micro]cc-FPD is capable of detecting very narrow (13 ms) chromatographic peaks. An ultrafast GC separation of a group of six OP and OS compounds is achieved within less than 5 s using fast temperature programming of a 0.5-m-long microbore column. Very fast separations are also demonstrated on a 1-m-long microfabricated column consisting of 150-[micro]m-wide, 240-[micro]m-deep channels, etched in a 1.9-cm square silicon chip, covered with a Pyrex wafer, and statically coated with dimethyl polysiloxane. With a hydrogen flow rate of 10 mL/min, the detection limit for OP is 12 pg of P/s and 3 ng of S/s for OS compounds at a signal-to-noise ratio of 2. The coupling of a microfabricated column and a miniature FPD is an important step toward the development of a miniaturized GC-FPD capable of ultrafast detection of low levels of OP and OS compounds.

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 [...]

Ground-based and spacecraft photometry covering phase angles from 2[degrees] to 179[degrees] has been acquired in wavelength bands from blue to near infrared. An unexpected brightness surge is seen in the B and V bands when the disk of Venus is less than 2% illuminated. This excess luminosity appears to be the result of forward scattering from droplets of [H.sub.2]S[O.sub.4] (sulfuric acid) in the high atmosphere of Venus. The fully sunlit brightness of Venus, adjusted to a distance of one AU from the Sun and observer, was found to be V = -4.38, and the corresponding geometric albedo is 67%. The phase integral is 1.35 and the resulting spherical albedo is 90%. Comparison between our data and photometry obtained over the past 50 years indicates a bias in the older photoelectric results, however atmospheric abundance variations suggest that brightness changes may have occurred too. Keywords: Venus; Atmospheres; Photometry

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

On-line coupling of reversed-phase microcolumn liquid chromatography (micro-RPLC) and sulfur-selective flame photometric detection (S-FPD) was studied for the selective and direct determination of thiodiglycol, bis(2-hydroxyethylthio)methane, 1,2-bis(2-hydroxyethylthio)ethane, 1,3-bis(2-hydroxyethylthio)propane, and 1,4-bis(2hydroxyethylthio)butane, which are breakdown products of the chemical warfare agents called sulfur mustards. Both isocratic and gradient elution were used. To improve sensitivity, large-volume injections were applied together with peak compression by displacement for late-during analytes. With S-FPD, detection limits of 1 (mu)g/mL were obtained for all compounds. Using the same approach, the target analytes as well as various oxidation products could be identified by micro-RPLC with electrospray ionization mass spectrometry (ESI-MS) and ESI-MS/MS. The optimized micro-RPLC-S-FPD system was successfully used for the analysis of a spiked soil sample.

Hydrolyzable carbohydrate intake in horse diets may become excessive when rapidly growing pastures are supplemented with grain-based concentrates. The substitution of fat and fiber for hydrolyzable carbohydrate in concentrates has been explored in exercising horses but not in young, growing horses. Our objective was to compare bone development in foals that were fed pasture and concentrates rich in sugar and starch (corn, molasses) or fat and fiber (corn oil, beet pulp, soybean hulls, oat straw). Forty foals were examined, 20 each in 1994 and 1995. In each year, 10 mares and their foals were fed a corn and molasses supplement (SS) and 10 others were fed a corn oil and fiber supplement (FF). The concentrates were formulated to be isocaloric and isonitrogenous, and mineral content was balanced to complement the pastures and meet or exceed NRC requirements. Dorsopalmar radiographs were taken of the left third metacarpal monthly from birth to weaning and then every other month until 1 yr of age. Bone density was estimated using imaging software and an aluminum stepwedge. Radiographic examination indicated differences in medial, lateral, and central bone mineral content of the metacarpal III. Bone mineral content increased with age, and a plateau was observed during winter. Bone mineral content was lower in weanlings and yearlings fed the FF supplement than in those fed SS. Subjective clinical leg evaluations indicated differences in physitis, joint effusion, and angular and fiexural limb deformities in response to age, and possibly to season. Regression analysis indicated positive relationships between bone mineral content and body weight, age, and body measurements. Nutrient and chemical interactions, such as the binding of calcium by fat and fiber, may alter the availability of elements necessary for bone development. Key Words: Radiographic Photometry, Bones, Bone Diseases, Foals

An investigation of brightness and color of Comet SL9 was carried out, when the comet had a phase angle less than 1 [degrees]. The color of the subnuclei was the same within error limits and was close to solar color. The g-r color of the dust increases along the tails of the subnuclei until they merge in the common dust envelope. Similarly in the common dust envelope there seems to be a trend of increased reddening with increased distance from the chain of subnuclei. The brightness peaks at minimum phase angle. Comparison with other observers indicates a phase curve similar to the phase dependence observed in C-type asteroids. The comet did not change its appearance when it passed minimum phase angle. This means that there is no evidence for fresh dust leaving the subnuclei in the form of syndyne tails or ongoing fragmentation producing micrometer-sized particles in the common dust envelope. We conclude that most of the dust present in the image was emitted either at breakup of the parent nucleus or a little later. As in this case the grains must be large as compared to the visual wavelength we can interpret the color as color of a macroscopic body. The fact that it is close to the solar color is consistent with the color of C-type asteroids. The color trend, if real, could then be due to separation of brighter and redder grains from the dark carbonaceous component by radiation pressure.

The photometric properties of the equatorial disturbances in Saturn are obtained from multicolor charge-coupled device (CCD) images at wavelengths from 370 to 900 nanometers. The CCD images were obtained from the Pic-du-Midi Observatory, France. The photometric properties are studied in former morphologically different regions. The study indicates the presence of ammonia clouds in Saturn's atmosphere.

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 [...]

The luminance and quantum yields of organic light emitting diodes (OLEDs) are calculated by using a hypothetic monochromatic emission. The calculation of the yield is practically unchanged, whatever hypothesis is used as shown by the demonstration.

Radiation hardness is one of the fundamental parameters characterizing a scintillator. The reason is that ionizing radiation often induces the formation of color centers in the irradiated material. These centers are related to lattice defects and may absorb light in the visible range. Possible overlap of the induced absorption spectrum with the emission spectrum of the scintillator can reduce the number of photons emitted by the scintillator, influencing negatively the energy resolution of the detector. In this paper, the irradiation ([sup.60]Co) induced absorption of [Ce.sup.3+] ([Tb.sup.3+]) phosphate scintillating glasses is reported in the dose range 1 / 10 Gy. Irradiation tests were performed in the 'Calliope' irradiation plant, placed in the Research Centre ENEA-Casaccia in the same dosimetric point (3.7 Gy/h), and the irradiation-induced damage was investigated by transmission measurements. Results are discussed by taking into account the possible dependence of radiation hardness on the composition of glass matrix. Index Terms--Glass, radiation effects, scintillation detectors.