1,721,088 research outputs found
Three-dimensional ultrasound palmprint recognition using curvature methods
No full textPalmprint recognition systems that use three-dimensional (3-D) information of the palm surface are the most recently explored techniques to overcome some two-dimensional palmprint difficulties. These techniques are based on light structural imaging. In this work, a 3-D ultrasound palmprint recognition system is proposed and evaluated. Volumetric images of a region of the human hand are obtained by moving an ultrasound linear array along its elevation direction and one by one acquiring a number of B-mode images, which are then grouped in a 3-D matrix. The acquisition time was contained in about 5 s. Much information that can be exploited for 3-D palmprint recognition is extracted from the ultrasound volumetric images, including palm curvature and other under-skin information as the depth of the various traits. The recognition procedure developed in this work is based on the analysis of the principal curvatures of palm surface, i.e., mean curvature image, Gaussian curvature image, and surface type. The proposed method is evaluated by performing verification and identification experiments. Preliminary results have shown that the proposed system exhibits an acceptable recognition rate. Further possible improvements of the proposed technique are finally highlighted and discussed
3-D Ultrasound Palmprint Recognition System Based on Principal Lines Extracted at Several Under Skin Depths
No full textIn recent years, several palmprint recognition procedures that use 3-D information on the palm surface have been proposed in order to overcome some limitations of 2-D palmprint. However, 3-D optical images provide information on the external skin surface only. Ultrasound waves have the capability to penetrate into human tissue and, therefore, can provide new kinds of 3-D information from acquired palmprints. In this paper, a 3-D ultrasound palmprint recognition system that accounts for principal line depth is proposed. It exploits several 2-D palmprints, extracted at different under skin depths with a classic procedure, opportunely combined to achieve a 3-D template. An ad hoc matching criterion is then defined in order to account for line depth information when comparing 3-D templates. Experiments of both verification and identification, performed on a homemade database, have shown that the 3-D recognition procedure exhibits very good recognition rates. The proposed 3-D technique also benefits from other advantages of ultrasound, including not being sensitive to many kinds of surface contaminations and its capability to detect liveness during the acquisition phase, which makes it very difficult to counterfeit
Valutazione della Presenza di Farine Animali nei Mangimi per Ruminanti mediante la Determinazione della Carnosina utilizzando la Cromatografia Ionica con Rivelazione Amperometrica Pulsata (HPAEC-IPAD)
No full textDeterminazione dell’Acido Orotico in Matrici Reali mediante Cromatografia Ionica e Rivelazione Amperometrica Pulsata
No full textA new recognition procedure for palmprint features extraction from ultrasound images
No full textIn this work, an improved palmprint recognition system based on 3D ultrasound images is proposed and experimentally validated. The system exploits an ultrasound gel pad as coupling medium, which results much more practical and non-invasive in real applications than water. An ad hoc recognition procedure has been derived; it uses as input a 2D image of the palmprint at a fixed under skin depth and extracts main features exploing the Frost filter and a series of morphological operations. The recognition system has been preliminarily evaluated through verification experiments carried out on an ad hoc established database composed of 75 samples from 17 different volunteers
Determination of Carnosine in Feeds and Meat Samples by High-Performance Anion-Exchange Cromatography with Integrated Pulsed Amperometric Detection
No full textCarnosine (-alanyl-l-histidine) is a dipeptide regarded as an important molecular marker of the presence of processed animal proteins including meat and bone meal in animal feed. For its identification and quantification a sensitive and selective method by high-performance anion-exchange chromatography coupled with integrated pulsed amperometric detection (HPAEC–IPAD) was developed. The assay is based on isocratic elution with 100mM NaOH as the mobile phase. Interferences of real matrices were efficiently removed; carnosine could be determined at the concentration ranges 0.1–100 uM with a rather low detection limit of 0.23 ng. Unlike feeds for dogs and cats, no carnosine peak was observed in all examined feeds for ruminants. The good analytical characteristics allowed carnosine determination down to 5 ug/g of feed
Experimental evaluation of 3D ultrasound Palmprint recognition techniques based on curvature methods and under skin principal lines
No full textIn this work, two procedures to extract 3D Palmprint features from a 3D ultrasound image of the human palm are presented and experimentally evaluated by using a database composed of 172 samples from 71 different users. Appreciable recognition results were found
Assessment of Fumonisins B1 and B2 Levels in Commercial Maize-Based Food Products by Liquid Chromatography with Fluorimetric Detection and Postcolumn Chemical Derivatization
No full textThe occurrence of the fumonisins B1 and B2 in maize-based food products marketed in Italy was examined. A simply and reliable chromatographic method with fluorimetric detection and postcolumn o-phtalaldehyde derivatization was used for a monitoring of 100 samples (8 flours, 21 corn-meal, 16 snacks, 7 maize samples, 13 gluten-free products, and 35 corn-flakes) bought in local supermarkets during the years 2008 and 2009. The presence of both fumonisins B1 and B2, at a concentration higher than 15 μg/kg, was observed in all samples of corn-meal and maize-flour, in 75% of snacks, in 57% of maize samples, in 54% of gluten-free products, and in 29% of corn-flakes. A total of 7 samples including 4 corn-meals, 2 maize-flours, and 1 maize showed a value exceeding the maximum level fixed in the Regulation 1126/2007/EC; no positive sample was observed in corn-flakes, snacks, and gluten-free foods. Fumonisins contamination, on the whole range of maize-based food products analyzed, emphasizes the need of improve agricultural practices, and increase official control and monitoring studies
A multiresidual method based on ion-exchange chromatography with conductivity detection for the determination of biogenic amines in food and beverages
No full textIn the present work a sensitive and accurate method by ion chromatography and conductimetric detection has been developed for the determination of biogenic amines in food samples at microgram per kilogram levels. The optimized extraction procedure of trimethylamine, triethylamine, putrescine, cadaverine, histamine, agmatine, spermidine, and spermine from real samples, as well as the separation conditions based on a multilinear gradient elution with methanesulfonic acid and the use of a weak ionic exchange column, have provided excellent results in terms of resolution and separation efficiency. Extended calibration curves (up to 200 mg/kg, r > 0.9995) were obtained for all the analyzed compounds. The method gave detection limits in the range 23-65 μg/kg and quantification limits in spiked blank real samples in the range 65-198 μg/kg. Recovery values ranged from 82 to 103 %, and for all amines, a good repeatability was obtained with precision levels in the range 0.03-0.32 % (n = 4). The feasibility and potential of the method were tested by the analysis of real samples, such as tinned tuna fish, anchovies, cheese, wine, olives, and salami. © 2012 Springer-Verlag Berlin Heidelberg
PULSED AMPEROMETRIC DETECTION AT GLASSY CARBON ELECTRODES: A NEW DETECTION SCHEME FOR SENSITIVE AND REPRODUCIBLE DETERMINATION OF POLYPHENOLS AND BETA-AGONISTS IN LIQUID CHROMATOGRAPHY
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