ICA-Based Algorithm Applied to Image Coding

©2007 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.International audienceRecently, Narozny et al [1] proposed a new viewpoint in variable high-rate transform coding. They showed that the problem of finding the optimal 1-D linear block transform for a coding system employing entropy-constrained uniform quantization may be viewed as a modified independent component analysis (ICA) problem. By adopting this new viewpoint, two new ICA-based algorithms, called GCGsup and ICAorth, were then derived for computing respectively the optimal linear transform and the optimal orthogonal transform. In this paper, we show that the transforms returned by GCGsup and ICAorth can achieve better visual image quality(better preservation of lines and contours) than the KLT and 2-D Discrete Cosine Transform (DCT) when applied to the compression of well-known grayscale images

ICA based algorithms for computing optimal 1-D linear block transforms in variable high-rate source coding

International audienceThe Karhunen-Loève Transform (KLT) is optimal for transform coding of Gaussian sources, however, it is not optimal, in general, for non-Gaussian sources. Furthermore, under the high-resolution quantization hypothesis, nearly everything is known about the performance of a transform coding system with entropy constrained scalar quantization and mean-square distortion. It is then straightforward to find a criterion that, when minimized, gives the optimal linear transform under the abovementioned conditions. However, the optimal transform computation is generally considered as a difficult task and the Gaussian assumption is then used in order to simplify the calculus. In this paper, we present the abovementioned criterion as a contrast of independent component analysis modified by an additional term which is a penalty to non-orthogonality. Then we adapt the icainf algorithm by Pham in order to compute the transform minimizing the criterion either with no constraint or with the orthogonality constraint. Finally, experimental results show that the transforms we introduced can (1) outperform the KLT on synthetic signals, (2) achieve slightly better PSNR for high-rates and better visual quality (preservation of lines and contours) for medium-to-low rates than the KLT and 2-D DCT on grayscale natural images

On simulations about the precision of non uniform hybrid filter bank analog/digital converters

©2006 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.International audienceIn this paper we present a theoretical study of the errors due to imperfect reconstruction and to quantization in hybrid filter bank (HFB) analog/digital (A/D) converters, that are non uniform i.e., with K channels and an arbitrary ratio M of the M-fold expanders (M ≤ K). We propose then a new method of simulation for such HFB A/D converters that avoids any numerical computation of differential equation solutions. The results of simulation are compared with theoretical ones. Moreover, in HFB A/D converter studies, the effect of quantization noise is generally indicated by its average power at the output of the HFB, when it is M-cyclostationary. This paper shows on an example that the variance of the global error at the HFB output can vary a lot in a period of M samples

Adapted generalized lifting schemes for scalable lossless image coding

International audienceStill image coding occasionally uses linear predictive coding together with multi-resolution decompositions, as may be found in several papers. Those related approaches do not take into account all the information available at the decoder in the prediction stage. In this paper, we introduce an adapted generalized lifting scheme in which the predictor is built upon two filters, leading to taking advantage of all this available information. With this structure included in a multi-resolution decomposition framework, we study two kinds of adaptation based on least squares estimation, according to different assumptions, which are either a global or a local second order stationarity of the image. The efficiency in lossless coding of these decompositions is shown on synthetic images and their performances are compared with those of well-known codecs (S+P, JPEG-LS, JPEG2000, CALIC) on actual images. Four images' families are distinguished: natural, MRI medical, satellite and textures associated with fingerprints. On natural and medical images, the performances of our codecs do not exceed those of classical codecs. Now for satellite images and textures, they present a slightly noticeable (about 0.05 to 0.08 bpp) coding gain compared to the others that permit a progressive coding in resolution, but with a greater coding time

Autoroute A64 « La Pyrénéenne », section Capvern-Pinas

Date de l'opération : 1989 (PR) Inventeur(s) : Veyssière Frédéric ; Barret Michel Le projet de liaison autoroutière Tarbes-Toulouse concerne un secteur à risques archéologiques qu’il convenait d’évaluer avec précision : industrie du paléolithique inférieur et moyen sur les communes de Pinas et de Lannemezan, tumulus du Premier Âge du fer à Capvern et Lannemezan, voie supposée antique à Pinas et Cantaous. Une prospection aérienne, doublée d’une prospection au sol, a permis de déceler dans des..

Totally laparoscopic aortic repair: A new device for direct transperitoneal approach

On the basis of our experience with more than 71 cases of totally laparoscopic aortic surgery by the retrocolic approach, we have developed a new technique by a simple transperitoneal approach. The purpose of this report is to describe that technique and the novel laparoscopic bowel retractor used to ensure stable exposure of the aorta

Discrete Wavelet Transform and Optimal Spectral Transform Applied to Multicomponent Image Coding

ISBN 978-953-307-482-5 Chapitre 10International audienc

Les organisations de producteurs en zone cotonnière au Mali

En Afrique de l’Ouest, les politiques de post ajustement donnent un rôle croissant aux organisations paysannes dans divers cadres de concertation où doivent se négocier les politiques sectorielles et se cogérer les filières agricoles. À travers le cas la filière coton au Mali, qui concerne près du quart de la population et un peu moins de 10 % du PIB, il est mis en balance les nouveaux enjeux auxquels se trouvent confrontées les organisations de producteurs et leurs capacités à les relever, capacités qui sont fortement liées aux diverses conditions de leur émergence. Les OP soit sont initiées par les pouvoirs publics (l’État ou la société cotonnière) soit émergent de la société civile à l’initiative des paysans ou d’Ong. La perspective d’une gestion interprofessionnelle de la filière coton en cours de privatisation permet de discuter des options offertes et de leurs implications en termes de règlementation, d’appuis et de recherches.In West Africa, post adjustment policies give an increasing role to farmers organizations within various concertation frameworks for the negotiation of sectoral policies and joint management of agricultural chains. Through the Malian cotton chain case which concerns about one quarter of the population and a little less than 10% of the GDP, the new challenges encountered by farmers’ organizations are confronted with their ability to face them. Thisability is strongly related to the various conditions of their emergence. Farmers’ organizations have been initiated by authorities (State or cotton Company) or have emerged from the civil society, initiated by peasants or Ngos. The prospect for an interprofessional management of the cotton chain under privatization allows the discussion of options offered and of their consequences for regulation, supports and research

The XMM-Newton serendipitous survey. VII. The third XMM-Newton serendipitous source catalogue

Thanks to the large collecting area (3 x ~1500 cm$^2$ at 1.5 keV) and wide field of view (30' across in full field mode) of the X-ray cameras on board the European Space Agency X-ray observatory XMM-Newton, each individual pointing can result in the detection of hundreds of X-ray sources, most of which are newly discovered. Recently, many improvements in the XMM-Newton data reduction algorithms have been made. These include enhanced source characterisation and reduced spurious source detections, refined astrometric precision, greater net sensitivity and the extraction of spectra and time series for fainter sources, with better signal-to-noise. Further, almost 50\% more observations are in the public domain compared to 2XMMi-DR3, allowing the XMM-Newton Survey Science Centre (XMM-SSC) to produce a much larger and better quality X-ray source catalogue. The XMM-SSC has developed a pipeline to reduce the XMM-Newton data automatically and using improved calibration a new catalogue version has been produced from XMM-Newton data made public by 2013 Dec. 31 (13 years of data). Manual screening ensures the highest data quality. This catalogue is known as 3XMM. In the latest release, 3XMM-DR5, there are 565962 X-ray detections comprising 396910 unique X-ray sources. For the 133000 brightest sources, spectra and lightcurves are provided. For all detections, the positions on the sky, a measure of the quality of the detection, and an evaluation of the X-ray variability is provided, along with the fluxes and count rates in 7 X-ray energy bands, the total 0.2-12 keV band counts, and four hardness ratios. To identify the detections, a cross correlation with 228 catalogues is also provided for each X-ray detection. 3XMM-DR5 is the largest X-ray source catalogue ever produced. Thanks to the large array of data products, it is an excellent resource in which to find new and extreme objects.Comment: 23 pages, version accepted for publication in A&