A System On Chip Dedicated To Pipeline Neighborhood Processing For Mathematical Morphology

Also available at http://www.eurasip.org/Proceedings/Eusipco/Eusipco2008/papers/1569104317.pdfInternational audienceThis paper describes a system on chip for image processing. It is based on a pipe-line of neighborhood processors named SPoC and is controlled by a general purpose processor. Each SPoC are connected one to the other through a reconfigurable data path to get more adaptability and their structure exploits temporal and spatial parallelism to speed up computations and minimize memory transfers. Two applications, a motion detection algorithm and a licence plate extraction, are presented to show performances in terms of speed, embeddability and re-usability of the SoC. Comparisons with many architectures such as digital signal processors, workstations or embedded SIMD processors are made to benchmark the platform and prove the originality and the strength of our solution

A multi-scale and morphological gradient preserving contrast

International audienceThis document outlines an algorithm which extends and enhances the regularised gradient. The regularised gradient is known to be a thin gradient. It has little noise, is multi-scale and has been extensively used, for instance, for the extraction of road markers from particularly challenging image sets. However, the intensity values taken by the regularised gradient are usually not representative of the perceived contrast across object boundaries. This limitation may prevent hierarchical segmentations based on the waterfalls or synchronous floodings from being meaningful with respect to the actual human perception of saliency. The proposed enhancement of the regularised gradient preserves the thinness and multi-scale properties of the latter whilst taking the actual contrast across different image scales into account

Depth map estimation: a region-based approach

This work has been performed in the project PANORAMA, co-funded by grants from Belgium, Italy, France, the Netherlands, and the United Kingdom, and the ENIAC Joint Undertaking.This paper presents an approach to the estimation of depth from stereo images which exploits correspondences of image segments. A key motivation is to bypass pixel correspondences which are ambiguous in texture-less regions. One of the main difficulty though is to come up to an equivalent partitioning of both stereo images that facilitates region matching. The reference image which the depth is estimated for is first segmented using the watershed algorithm. Regions are then transferred to the other image of the stereo pair according to a correlation analysis of region contours. This transfer yields regional disparities which are significant as long as the contours for a given region are not due to an occlusion. Based on that observation, we propose an algorithm that detects occlusion contours along a region and that rectifies disparity accordingly

Multistep Detection of Oriented Structure in Complex Textures

International audienceIn the context of online industrial control, we propose a multistep method, based on mathematical morphology operators, to carry out the characterization of oriented structures in a complex texture environment. In a data base of about ten thousand patches, ten percent show various oriented structures. First we measure for each patch the x and y covariances, and apply pyramids of dilations-erosions and openings-closings using linear structuring elements. Second we transform the resulting pyramid images into usable condensed information. All the measures for each patch set up texture descriptors. For each of them we apply a Principal Components Analysis (PCA) to sum up the information. Then we use a Linear Discriminant Analysis (LDA) on the principal axes which carry the most information and analyze in the LDA space the distribution of the two types of patches to reach 99.45% of sensitivity and 99.61% of specificity

Morphological processing of stereoscopic image superimpositions for disparity map estimation

This paper deals with the problem of depth map computation from a pair of rectified stereo images and presents a novel solution based on the morphological processing of disparity space volumes. The reader is guided through the four steps composing the proposed method: the segmentation of stereo images, the diffusion of superimposition costs controlled by the segmentation, the resulting generation of a sparse disparity map which finally drives the estimation of the dense disparity map. An objective evaluation of the algorithm's features and qualities is provided and is accompanied by the results obtained on Middlebury's 2014 stereo database

New Operator Based on a Multi Support Point Algorithm Applied to Feature Extraction

International audienceIn the context of quality control, we propose a new operator using multi support points to highlight local perturbations on flat surfaces. We compare the design of this operator with different gradients and residues in their ability to extract small perturbations as well as their efficiency on large surface. The operator is defined as a weighted differential operator evaluated on each point. It is designed to extract a region with a high slope followed by a plateau with a given width. It has a low computational complexity and it could be vectorized

Appariements de régions pour l'estimation de cartes de profondeur

International audienceEn vision stéréoscopique binoculaire, les coordonnées spatiales d'un point de la scène peuvent être déduites de ses projections dans les deux images formées. Trouver les projections qui se correspondent constitue cependant la principale difficulté du problème et ce pour deux raisons: l'ambiguïté des appariements au travers des régions homogènes et l'impossibilité de trouver une correspondance valide en cas d'occultation.Cet article propose une méthode d'estimation de cartes de profondeur utilisant l'appariement de régions plutôt que de points. Ces appariements sont effectués à deux échelles de segmentation obtenues au moyen de critères morphologiques assurant l'existence d'une relation hiérarchique entre les partitions fine et grossière. La hiérarchie peut alors être exploitée afin d'obtenir des cartes de disparité régionales fines non bruitées desquelles les cartes de profondeur finales sont déduites.Enfin, nous montrons comment cette méthode s'adapte à différents types d'images stéréoscopiques: des images fortement texturées acquises dans les même conditions d'illumination à celles ayant une faible dynamique de disparités et dont les contours constituent la seule source d'information pertinente.</p

A top-down methodology to depth map estimation controlled by morphological segmentation

Given a pair of stereo images and the transformation existing between the corresponding camera coordinate systems, the depth of a scene point can be computed from its projections on both images. Despite the difficulties related to the matching of such projections across homogeneous regions and the occlusion phenomenon, state of the art methods have already produced accurate results on classical stereo datasets. This article proposes a new way of approaching depth estimation. Instead of searching for dense pixel correspondences, a gross estimation of the disparities is initially performed at the region level, resulting in a regional disparity map which highlights the principal depth layers of the image. The disparity map is then systematically refined by considering finer partitions of the image. To this end, the watershed of the image colour gradient is selected in order to compute the image partitions alongside a meaningful hierarchy. We show that the ability to be driven by labelled markers enables the watershed algorithm to generate a co-segmentation of both stereo images given the regional disparities, which constitutes the main contribution of this paper. This co-segmentation allows one to reliably compute the disparities of pixels along the region contours. Finally, the contour disparities are transferred to the concerned regions after a careful analysis of their occlusion state with respect to each adjacent region. Though approximate, we show that the proposed method yields regional disparity maps which are close enough to ground truths in the view of performing the desired refinements. We also expose the perspectives of this methodology with respect to challenging stereo imagery, i.e. which is affected by noise or which contains a considerable amount of homogeneous regions

Texture Analysis with Arbitrarily Oriented Morphological Opening and Closing

13 pagesThis paper presents a fast, streaming algorithm for 1-D morphological opening on 2-D support. The algorithm is further extended to compute the complete size distribution during a single image run. The Structuring Element (SE) can be oriented under arbitrary angle that allows us to perform different orientation-involved image analysis, such as local angle extraction, directional granulometries, \etc The algorithm processes an image in constant time irrespective of the SE orientation and size, with a minimal latency and very low memory requirements. Regardless the SE orientation, it reads and writes data strictly sequentially in the horizontal scan order. Aforementioned properties allow an efficient implementation in embedded hardware platforms that opens a new opportunity of a parallel computation, and consequently, a significant speed-up

Development of a long term monitoring network of sensitive clay slopes in Québec in the context of climate change

The Government of Québec recently initiated the deployment of a vast groundwater pressures monitoring network in postglacial marine clays to document their variations in time and improve our understanding of the relationship between failure initiation and climate in clay slopes. This project aims at evaluating the impacts of climate change on clay-slope stability and how it can be integrated in landslide risk management to improve public safety. Hydrogeological data will be acquired at sites located throughout the Québec Province’s post-glacial clay deposits to create a public georeferenced index of typical hydrogeological conditions. The project goes beyond the characterization of groundwater pressures and their variations in clay slopes. Indeed, slope deformation will be measured at several sites. Also, two sites in flat terrain will be instrumented in order to evaluate mechanical properties of clay layers in simple 1-D conditions and groundwater recharge. The unsaturated clay crust in slopes susceptible to superficial landslides will be characterized and instrumented. The current lifetime of the monitoring project has been set to a period of 25 years.