Search results for " Computer science"
showing 10 items of 3983 documents
A Digital Watermarking Algorithm Based on Quantization of the DCT: Application on Medical Imaging
2013
International audience; The objective of this paper is to elaborate a new watermarking algorithm applied to the medical imaging. This algorithm must be invisible, robust and has a rate, relatively high, integrating data. The proposed method uses the standard JPEG compression for the integration of medical data. The insertion block is inserted just after the quantization phase. To control identification and eventually the correction (if possible) of the inserted data, we use a series of turbocodes to recover the inserted data, after application of several attacks. The simulation studies are applied on MRI medicals images.
Editorial for Special Issue “Fine Art Pattern Extraction and Recognition”
2021
Cultural heritage, especially the fine arts, plays an invaluable role in the cultural, historical, and economic growth of our societies [...]
A comparison study of evolutive algorithms for solving the partitioning problem in distributed virtual environment systems
2004
Fast Internet connections and the widespread use of high performance graphic cards are making Distributed Virtual Environment (DVE) systems very common nowadays. However, there are several key issues in these systems that should still be improved in order to design a scalable and cost-effective system. One of these key issues is the partitioning problem. This problem consists of efficiently assigning clients (3D avatars) to the servers in the system. In this paper, we present a comparison study of different modern heuristics for solving the partitioning problem in DVE systems, as an alternative to the ad hoc heuristic proposed in the literature. Performance evaluation results show that some…
Robust technique for 3D shape reconstruction
2017
Abstract In this paper a robust and simple scheme is presented for three dimensional (3D) shape reconstruction of real object. A novel composite pattern technique is proposed for projecting the light pattern on the object of interest. The proposed scheme reduces the number of patterns by combining the primary color coded channels into one composite format. Our approach uses both spatial and temporal intensity variation for calibration and construction phase. Gamma calibration is considered with the propose scheme. High quality depth map is obtained from the linear light reflected by the shape of object without complex calculations. Experimental results demonstrated that proposed technique i…
Economic Robustness Analysis of Adaptive Chart Schemes for Monitoring the Total Nonconformities Number in Inspection Units
2015
In recent years, a variety of enhanced schemes for the c chart have been developed aimed at the effectiveness improving of the related statistical process control (SPC) procedures. However, the performance of such chart schemes can be very sensitive to values assumed for some operating and cost parameters, in particular to the considered process shift magnitude arising from out-of-control conditions. In such a circumstance, the effectiveness of such chart schemes can be subjected to substantial reductions when they are implemented in operative contexts given that, in practice, such value is unknown and it can be very difficult to accurately estimate. For this reason, in the present paper i…
Measurement of three-dimensional mirror parameters by polarization imaging applied to catadioptric camera calibration
2008
International audience; We present a new efficient method for calibration of cata- dioptric sensors. The method is based on an accurate measurement of the three-dimensional parameters of the mirror through polariza- tion imaging. While inserting a rotating polarizer between the cam- era and the mirror, the system is automatically calibrated without any calibration patterns. Moreover, this method permits most of the constraints related to the calibration of catadioptric systems to be relaxed. We show that, contrary to our system, the traditional meth- ods of calibration are very sensitive to misalignment of the camera axis and the symmetry axis of the mirror. From the measurement of three-di…
Jointure G 2 de deux courbes par une courbe de Bézier rationnelle à points massiques de contrôle
2023
Cet article s'intéresse aux jointures entre deux courbes données par une courbe de Bézier rationnelle quintique à points massiques de contrôle. Pour ce faire, les propriétés différentielles de ces courbes de Bézier fournissent les formules de calcul des courbures en 0 et 1 ainsi que le cercle osculateur idoine. Chaque jointure présente deux degrés de liberté où deux points appartiennent chacun à une droite. Si la jointure G 2 est aussi une jointure C 2 alors la solution est unique. Après le cas d'école d'une jointure entre un cercle et une droite et en guise d'illustration des résultats, deux exemples de jointures entre les boucles d'un Folium de Descartes et d'une Lemniscate de Bernouilli …
A Solution to the Problem of the Maximal Number of Symbols for Biomolecular Computer
2019
The authors present a solution to the problem of generating the maximum possible number of symbols for a biomolecular computer using restriction enzyme BbvI and ligase as the hardware, and transition molecules built of double-stranded DNA as the software. The presented solution offers an answer to the open question, in the algorithm form, of the maximal number of symbols for a biomolecular computer that makes use of the restriction enzyme BbvI.
A fast algorithm for the exhaustive analysis of 12-nucleotide-long DNA sequences. Applications to human genomics
2004
We have developed a new algorithm that allows the exhaustive determination of words of up to 12 nucleotides in DNA sequences. It is fast enough as to be used at a genomic scale running on a standard personal computer. As an example, we apply the algorithm to compare the number of all 12-nucleotide long words in human chromosomes 21 and 22, each of them more than 33 million nucleotides long. Sequences that are chromosome specific are detected in less than 2 minutes, being analyzed any pair of chromosomes at a rate of 45 millions of nucleotides (45 Mb) per minute. The size of the words is long enough as to allow further analyses of all significant sequences using conventional database searche…
Design of a customized pattern for improving color constancy across camera and illumination changes
2010
International audience; This paper adresses the problem of color constancy on a large image database acquired with varying digital cameras and lighting conditions. Automatic white balance control proposed by an available commercial camera is not sufficient to provide reproducible color classification. A device-independent color representation may be obtained by applying a chromatic adaptation transform, from a calibrated color checker pattern included in the field of view. Instead of using the standard Macbeth color checker, we suggest to select judicious colors to design a customized pattern from contextual information. A comparative study demonstrates that this approach insures a stronger…