Éditeur(s) : HAL CCSD Hong Kong : World Academic Publishing
Résumé : International audience
In automatic image analysis, when using natural images, it is important to select the elements in a scene that can lead to correct characterization. Extraneous elements can result in poor values in the parameter evaluation for recognition. Irrelevant elements also increase the processing time, because they can be used incorrectly by the algorithms for characterization or identification. The goal of this paper is to offer identification algorithms and characterizations that will allow effective recognition. We base our procedure on the photographer focus areas to identify those relevant elements in a scene. In this work, we propose a procedure to select the relevant shape from natural images. The treatment uses focal depth with edge detectors. The resulting points are combined with a region partition to obtain relevant shapes.
ISSN: 2309-0650

hal-01278550
https://hal.archives-ouvertes.fr/hal-01278550

Éditeur(s) : Elsevier Science Bv
Résumé : Fluid escape structures on the Nile Deep Sea Fan were investigated during the MEDIFLUX MIMES expedition in 2004. Mud volcanoes, pockmarks and authigenic carbonate structures were surveyed for the first time with a high-resolution deep-towed 75 kHz sidescan sonar and a 2-8 kHz Chirp sediment echosounder. In combination with existing multibeam bathymetry and detailed seafloor in situ geological observations, these new data allowed detailed seep analyses. About 60 gas flares were detected acoustically in the water column from the sidescan sonar raw data at water depths from 770 to 1700 m. These gas flares coincide at the seabed with 1) the centres of the mud volcanoes where mud is also extruded, 2) the borders of the mud volcanoes where the emitted gases contribute to the precipitation of authigenic carbonates, and 3) to the edges of broad sheets of authigenic carbonates. Subsurface sediments are commonly disturbed by ascending fluids throughout the delta, with an abundance of seep-related carbonate structures on the seafloor. The feeder channels below mud volcanoes, similar to the gas conduits below the widespread carbonate crust structures and pockmarks, are relatively narrow and, for the vast majority of them, do not exceed a few metres in diameter. The seeps on the Nile Deep Sea Fan clearly follow lineations on the seafloor that we can relate to faults. (C) 2010 Elsevier B.V. All rights reserved.
Marine Geology (0025-3227) (Elsevier Science Bv), 2010-09 , Vol. 275 , N. 1-4 , P. 1-19

Droits : 2010 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/00013/12457/9766.pdf
DOI:10.1016/j.margeo.2010.04.003
http://archimer.ifremer.fr/doc/00013/12457/

Éditeur(s) : HAL CCSD
Résumé : International audience
This paper deals with image processing. This study takes place in a segmentation process based on texture analysis. We use the multifractal ap-proach to characterize the textures. More precisely we study a particular multi-fractal spectrum called the large deviation spectrum. We consider two statistical methods to numerically compute this spectrum. The resulting spectrum, com-puted by both methods over an image, is a one dimension spectrum. In the scope of this article, we extend these methods in order to obtain a two dimen-sions spectrum which could be assimilated to an image. This 2D spectrum al-lows a local characterization of the image singularities while a 1D spectrum is a global characterization. Moreover, the computation of the spectrum requires the use of a measure. We introduce here a pre processing based on the gradient to improve the measure. We show results on both synthetic and real world images. Finally, we remark that the resulting 2D spectrum is close to the resulting im-age of an edge detection process while edge detection using one dimension spectrum requires post processing methods. This statement will be used for fu-ture works.
SITIS Proceedings
Hammamet, Tunisia

hal-00602273
https://hal.archives-ouvertes.fr/hal-00602273

Éditeur(s) : HAL CCSD
Résumé : International audience
Half away between edge detection and object recognition this study aim to characterize singularities in order to guide this two phases. The caracterization is obtained with a generalization of the Lipschitz exponents .for complex structures. This new characterization is called " maxima chain " and integrates the notion of value and spatial repartition of the maxima. The maxima chains are obtained with a multiscale decomposition using a Diadic Discrete Wavelet Transform (DDWT). We use the maxima of the gradient image computed with the wavelet details. The local maxima detect the position of irregular structures (edges) in the image (Canny algorithm). Then we characterize each maxima using their evolution across the different scales. A classification is made using the maxima chains. We integrate the classification to eliminate unwanted maxima (from noise or other objects) to drive the search of closed contours. In fact, there is a totally different signature from one maxima to another depending on the parameters of the objects : nature, shape, size, gray scale, texture, ...
RFIA Proceedings
Toulouse, France

hal-00602265
https://hal.archives-ouvertes.fr/hal-00602265

Éditeur(s) : HAL CCSD
Résumé : International audience
Half away between edge detection and pattern recognition this study aim to characterize singularities in order to build closed edges and to classify object within an image.
IGARSS
Toulouse, France

hal-00602262
https://hal.archives-ouvertes.fr/hal-00602262