Michel J.,Jean Monnet University |
Maxime C.,Jean Monnet University |
Josselin B.,Silab |
Advances in Imaging and Electron Physics | Year: 2012
The logarithmic image processing model is now recognized as a powerful framework to process images acquired in transmitted light and to take into account the human visual system. One of its major interests is linked to the strong mathematical properties it satisfies, allowing the definition and use of rigorous operators. In this paper, we introduce the concept of logarithmic additive contrast (LAC), its physical interpretation based on transmittance notion and some resulting properties: It represents by definition a grey level and it is highly efficient when computed on dark pairs of pixels, with applications for low-lighted images. Then the LAC is compared with the classical Michelson contrast, showing an explicit link between them. Furthermore, the LAC is demonstrated as very useful in the fields of automated thresholding and contour detection. Another major interest of the LAC is that it allows defining logarithmic metrics, opening various applications: grey-level images comparison, pattern recognition, target tracking, defect detection in industrial vision, and the creation of a new class of automated thresholding algorithms. Another part of the paper is dedicated to a novel notion of logarithmic multiplicative contrast (LMC), which appears as a positive real number and also presents a "physical" interpretation in terms of transmittance. Our research concerning the LMC remains today at an exploratory level if we consider the number of possible ways to deepen this notion. In fact, the LMC values may exceed the grey-scale maximum, which necessitates some normalization to display them as a contrast map. Nevertheless, the LMC is very sensitive near the bright extremity of the grey scale, which is very useful in processing overlighted images. As does the LAC, the LMC generates many new metrics, particularly the Asplünd one, and a metric combining information on shapes and grey levels. Until now, Asplünd's metric had been defined for binary shapes and is extended here to grey-level images, with interesting applications to pattern recognition. © 2012 Elsevier Inc. All rights reserved.
Jourlin M.,CNRS Hubert Curien Laboratory |
Breugnot J.,CNRS Hubert Curien Laboratory |
Itthirad F.,CNRS Hubert Curien Laboratory |
Bouabdellah M.,NT2I |
Advances in Imaging and Electron Physics | Year: 2011
The adaptation of grey-level logarithmic image processing to color is used to provide new kinds of tools for manipulating color images within the framework of a mathematically and physically justified model. These techniques are adapted for human perception in the use of color matching functions of the human eye in the elaboration of the model parameters. The results are found to depend on the precision of the color matching function used, and that diffusion and reflection phenomena are not yet taken into account. Some significant improvement has also been realized considering algorithm execution time, demonstrating that real-time treatments can be performed Results also show that that gain compensation is not enough and that saturation areas appear with the equalization. The algorithm provides details and the level of correction can be chosen.
Silab | Date: 2014-05-01
A yeast strain expressing a bi-functional fucokinase/GDP-L-fucose pyrophosphorylase enzyme and capable of producing GDP-L-fucose in vivo is provided. Also provided are yeast cells which express a GDP-L-fucose transporter and/or a fucosyl transferase with the bi-functional enzyme. In addition, the said yeast contains one or more expression cassettes for fusion proteins of heterologous glycosylation pathway and an ER/Golgi retention sequence. Finally, the invention also provides a method for producing recombinant target glycoproteins.
Gloaguen V.,University of Limoges |
Brudieux V.,University of Limoges |
Closs B.,Silab |
Barbat A.,University of Limoges |
And 5 more authors.
Journal of Natural Products | Year: 2010
Zosterin, an apiose-rich pectic polysaccharide, was extracted and purified from the sea grass Zostera marina. Structural studies conducted by gas chromatography and NMR spectroscopy on a purified zosterin fraction (AGU) revealed a typical apiogalacturonan structure comprising an α-1,4-d- galactopyranosyluronan backbone substituted by 1,2-linked apiofuranose oligosaccharides and single apiose residues. The average molecular mass of AGU was estimated to be about 4100 Da with a low polydispersity. AGU inhibited proliferation of A431 human epidermoid carcinoma cells with an approximate IC50 value of 3 μg/mL (0.7 μM). In addition, AGU inhibited A431 cell migration and invasion. Preliminary experiments showed that inhibition of metalloproteases expression could play a role in these antimigration and anti-invasive properties. Autohydrolysis of AGU, which eliminated apiose and oligo-apiose substituents, led to a virtual disappearance of cytotoxic properties, thus suggesting a direct structure-function relationship with the apiose-rich hairy region of AGU. © 2010 The American Chemical Society and American Society of Pharmacognosy.
Jourlin M.,CNRS Hubert Curien Laboratory |
Corvo J.,Silab |
Pattern Recognition | Year: 2014
The present paper focuses on non-linear pattern matching based on the Logarithmic Image Processing (LIP) Model. Our contribution consists first of using the scalar multiplication defined in the LIP context to extend the little-known Asplünds metric to gray level images. Such a metric is explainable as a novel technique of double-sided image probing and presents the decisive advantage of being physically justified in the field of transmitted light acquisition. Moreover, thanks to the consistency of the LIP context with human vision, Asplünds metric is also applicable to images acquired in reflected light: in fact, plenty of image processing algorithms aim at extracting information as a human eye would do. Finally, the proposed approach is particularly efficient in the presence of lighting variations or lighting drift. In the paper, we also suggest a solution to overcome the main drawback of probing techniques, which resides in a high sensitivity to noise. Various examples are presented to highlight the efficiency of the method. © 2014 Elsevier Ltd.