排序方式: 共有14条查询结果,搜索用时 701 毫秒
1.
Burie Jean-Christophe Fornés Alicia Santosh K. C. Luqman Muhammad Muzzamil 《International Journal on Document Analysis and Recognition》2021,24(1-2):1-2
International Journal on Document Analysis and Recognition (IJDAR) - 相似文献
2.
Detection of Carbon Dioxide in Air Using Difference-Frequency Generation Based Infrared Spectrometer
Weidong Chen Gaël Mouret Jean Burie Daniel Boucher 《Journal of Infrared, Millimeter and Terahertz Waves》1998,19(3):409-417
Spectroscopic detection of carbon dioxide (CO2) in ambient air was performed using a continuous-wave mid-infrared spectrometer based on difference-frequency generation in an AgGaS2 crystal. Significant improvement in nonlinear optical frequency conversion efficiency was achieved by Gaussian beam optical design consideration. CO2 concentration was determined from direct-absorption spectral measurement. 相似文献
3.
Cu Vinh Loc Nguyen Trac Burie Jean-Christophe Ogier Jean-Marc 《International Journal on Document Analysis and Recognition》2020,23(3):219-239
International Journal on Document Analysis and Recognition (IJDAR) - Motivated by increasing possibility of the tampering of genuine documents during a transmission over digital channels, we focus... 相似文献
4.
D. Boucher R. Bocquet W. Chen J. Burie 《Journal of Infrared, Millimeter and Terahertz Waves》1993,14(10):1889-1903
Low noise heterodyne receivers are now used in a large variety of instruments such as radiotelescopes, far infrared laser side bands spectrometers, supersonic nozzle beams Fourier transform spectrometers, lidars or plasmas diagnostics devices. Numerous papers have been devoted to the analysis of heterodyne receivers in the attempt to reach ultimate performances. These previous papers usually retain the restrictive hypothesis of vanishingly small signal powers. Such a condition occurs only in a restrictive number of applications, radioastronomic systems being probably among the most representative examples. Spectroscopic instruments operate usually in a different regime. The signal to be detected consists of a small variation in the source power. The absolute value of this source power largely depends on the available technology in the spectral range of interest. The purpose of this paper is to analyze the behavior of heterodyne detection in the general case. The results apply to a large category of systems including spectroscopic instruments. The influence of crucial parameters such as source power and predetection bandwidth is analysed in details. The theory is experimentally tested on an example of ultra low noise receiver designed for far infrared laser side bands spectroscopy. Some numerical calculations are proposed, illustrating methods for an optimal sizing of receiver's predetection bandwidth and the estimation of ultimate sensitivity of spectrometers. 相似文献
5.
6.
Chen W Poullet E Burie J Boucher D Sigrist MW Zondy JJ Isaenko L Yèlisseyev A Lobanov S 《Applied optics》2005,44(19):4123-4129
The first demonstration, to the best of our knowledge, of continuous-wave (cw) difference-frequency generation (DFG) in LiInS2 crystal is reported. Wide spectral coverage (5.5-11.3 microm) has been obtained with angle and wavelength tuning for type II (eoe) critically phase-matched parametric interaction. The phase-matching conditions in cw DFG have been investigated, which allowed us to improve the Sellmeier parameters by use of a two-pole dispersion equation. An effective nonlinear coefficient deff = 6.9 +/- 0.8 pm/V has been determined at approximately 7 microm relative to the well-known nonlinear coefficient d36 of AgGaS2, which yields a power-conversion efficiency of approximately 12.4 microW/(W2 cm). We evaluated the high-resolution spectral characteristics of the DFG source by recording C2H2 and SO2 spectra. 相似文献
7.
R. Raveaux J. C. Burie J. M. Ogier 《International Journal on Document Analysis and Recognition》2012,15(1):21-43
This paper presents a benchmark for evaluating the raster to vector conversion systems. The benchmark is designed for evaluating
the performance of graphics recognition systems on images that contain polygons (solid) within the images. Our contribution
is two-fold, an object mapping algorithm to spatially locate errors within the drawing and then a cycle graph matching distance
that indicates the accuracy of the polygonal approximation. The performance incorporates many aspects and factors based on
uniform units while the method remains non-rigid (thresholdless). This benchmark gives a scientific comparison at polygon
level of coherency and uses practical performance evaluation methods that can be applied to complete polygonization systems.
A system dedicated to cadastral map vectorization was evaluated under this benchmark and its performance results are presented
in this paper. By stress testing a given system, we demonstrate that our protocol can reveal strengths and weaknesses of a
system. The behavior of our set of indices was analyzed when increasing image degradation. We hope that this benchmark will
help assessing the state of the art in graphics recognition and current vectorization technologies. 相似文献
8.
J Breton JR Burie C Berthomieu G Berger E Nabedryk 《Canadian Metallurgical Quarterly》1994,33(16):4953-4965
Light-induced FTIR difference spectra of the photoreduction of the primary quinone acceptor QA have been obtained for Rhodobacter sphaeroides RCs reconstituted with a series of isotopically labeled quinones in order to separate the contributions of the quinone from those of the protein. The isotopic shifts observed in the QA-/QA spectra of RCs reconstituted with ubiquinones (Q1, Q6) or vitamin K1 18O-labeled on their carbonyl oxygens and with fully 13C-labeled Q8 lead to a clear identification of the quinone bands from both the neutral and anion forms. Double-difference spectra from pairs of QA-/QA spectra obtained from 18O/16O Q6, 18O/16O Q1, 13C/12C Q8, 13C18O/12C16O Q8, and 18O/16O vitamin K1 allow the C = O modes of QA in vivo to be identified unambiguously for the first time. For all the investigated unlabeled quinones, two carbonyl bands are demasked, at 1660 and 1628 cm-1 for neutral ubiquinones and at 1651 and 1640 cm-1 for vitamin K1, while C = C bands are found at 1608 and 1588 cm-1 for vitamin K1 and at 1601 cm-1 for ubiquinones. Compared with the spectra of the isolated quinones, the generally smaller width observed for the C = O and C = C bands in vivo suggests precise interactions between the quinone and the contours of the protein at a single, well-defined QA site. The different frequency downshifts of the two C = O bands upon binding to the QA site underscore the inequivalence of the two carbonyls in providing asymmetrical bonding interactions with the protein. The comparison of the isotopic shifts observed for the various quinone C = O and C = C bands in vitro and in vivo demonstrates that the admixture of C = O and C = C characters in these modes is strongly affected by the binding of QA to its anchoring site. In particular, the bands at 1628 and 1601 cm-1 of Q6 in vivo exhibit highly mixed C = O and C = C characters. In contrast, the methoxy groups of the ubiquinones do not appear to suffer large strain upon binding. The closeness of the QA-/QA spectra for Q1 and Q6 indicates that a possible role of the chain in providing the proper positioning of the quinone ring in the site for both the oxidized and reduced states of QA cannot extend significantly beyond the first isoprene unit.(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献
9.
Romain Raveaux Jean-Christophe Burie Jean-Marc Ogier 《Journal of Visual Communication and Image Representation》2013,24(8):1252-1268
Here, we propose an automatic system to annotate and retrieve images. We assume that regions in an image can be described using a vocabulary of blobs. Blobs are generated from image features using clustering. Features are locally extracted on regions to capture Color, Texture and Shape information. Regions are processed by an efficient segmentation algorithm. Images are structured into a region adjacency graph to consider spatial relationships between regions. This representation is used to perform a similarity search into an image set. Hence, the user can express his need by giving a query image, and thereafter receiving as a result all similar images. Our graph based approach is benchmarked to conventional Bag of Words methods. Results tend to reveal a good behavior in classification of our graph based solution on two publicly available databases. Experiments illustrate that a structural approach requires a smaller vocabulary size to reach its best performance. 相似文献
10.
W. Chen R. Rocquet J. Burie D. Boucher 《Journal of Infrared, Millimeter and Terahertz Waves》1997,18(1):217-232
A submillimeter-wave/far-infrared (SMM/FIR) laser sideband heterodyne spectrometer has been built for molecular rotational spectroscopy application in the frequency range of 600–3000 GHz. Based on Gaussian optics, optical system of the spectrometer is designed to be quasi-achromatic and low losses. In this article the optical design and the performance of the spectrometer are presented. 相似文献