Computationally efficient, one-pass algorithm for morphological filters

International audienceMany useful morphological filters are built as long concatenations of erosions and dilations: openings, closings, size distributions, sequential filters, etc. This paper proposes a new algorithm implementing morphological dilation and erosion of functions. It supports rectangular structuring element, runs in linear time w.r.t. the image size and constant time w.r.t. the structuring element size, and has minimal memory usage. It has zero algorithm latency and processes data in stream. These properties are inherited by operators composed by concatenation, and allow their efficient implementation. We show how to compute in one pass an Alternate Sequential Filter (ASF(n)) regardless the number of stages n. This algorithm opens the way to such time-critical applications where the complexity and memory requirements of serial morphological operators represented a bottleneck limiting their usability. (C) 2011 Elsevier Inc. All rights reserved

Grey-scale 1-D dilations with spatially-variant structuring elements in linear time

Full text also available online for free at http://www.eurasip.org/Proceedings/Eusipco/Eusipco2008/International audienceSpatially variant morphological operators can significantly improve filtering capabilities or object detection score of various applications. Whereas an effort has been made to define the theoretical background, the efficient implementation of adaptable algorithms remained far less considered. In this paper, we present an efficient,one-scan, linear algorithm for 1-D grey-scale dilations/erosions with spatially variant structuring elements. The proposed algorithm processes data in stream, can work in place and produces results with minimal latency. The computing time is independent of the structuring element size

Region Growing Structuring Elements and New Operators Based on Their Shape

International audienceThis paper proposes new adaptive structuring elements in the framework of mathematical morphology. These structuring elements (SEs) have a fixed size but they adapt their shape to the image content by choosing, recursively, similar pixels in gray-scale, with regard to the seed pixel. These new SEs are called region growing structuring elements (REGSEs). Then, we introduce an original method to obtain some features by analyzing the shape of each REGSE. We get a powerful set of operators, which is able to enhance efficiently thin structures in an image. We illustrate the performance of the proposed filters with an application: the detection of cracks in the framework of non-destructive testing. We compare these methods with others, including morphological amoebas and general adaptive neighborhood structuring elements and we see that these operators, based on REGSE, yield the best detection for our application

Geometry Analysis of Superconducting Cables For The Optimization of Global Performances

International audienceSuperconducting cables have now become a mature technology for energy transport, high-field magnets (MRI, LHC) and fusion applications (ToreSupra, and eventually ITER and DEMO). The superconductors are extremely brittle and suffer from electrical damages brought by mechanical strain induced by electromagnetic field that they generate. An optimal wiring architecture, obtained by simulation, can limit these damages. However, the simulation is a complex process and needs validation. This validation is performed on real 3D samples by the means of image processing. Within this objective, this paper is, to our best knowledge, the first one to present a method to segment the samples of three types of cables as well as a shape and geometry analysis. Preliminary results are encouraging and intended to be later compared to the simulation results

Efficient geodesic attribute thinnings based on the barycentric diameter

International audienceAn attribute opening is an idempotent, anti-extensive and increasing operator, which removes from an image connected components which do not fulfil a given criterion. When the increasingness property is dropped, we obtain a - more general - attribute thinning. In this paper, we propose efficient grey scale thinnings based on geodesic attributes. Given that the geodesic diameter is time consuming, we propose a new geodesic attribute, the barycentric diameter to speed up the computation time. Then, we give the theoretical error bound between these two attributes, and we note that in practice, the barycentric diameter gives very similar results in comparison with the geodesic diameter. Finally, we present the algorithm with further optimisations, to obtain a 60× speed up. We illustrate the use of these thinnings in automated non-destructive material inspection: the detection of cracks. We discuss the advantages of these operators over other methods such as path openings or the supremum of openings with segments

Parsimonious Path Openings and Closings

International audiencePath openings and closings are morphological tools used to preserve long, thin and tortuous structures in gray level images. They explore all paths from a defined class, and filter them with a length criterion. However, most paths are redundant, making the process generally slow. Parsimonious path openings and closings are introduced in this paper to solve this problem. These operators only consider a subset of the paths considered by classical path openings, thus achieving a substantial speed-up, while obtaining similar results. Moreover, a recently introduced one dimensional (1-D) opening algorithm is applied along each selected path. Its complexity is linear with respect to the number of pixels, independent of the size of the opening. Furthermore, it is fast for any input data accuracy (integer or floating point) and works in stream. Parsimonious path openings are also extended to incomplete paths, i.e. paths containing gaps. Noise-corrupted paths can thus be processed with the same approach and complexity. These parsimonious operators achieve a several orders of magnitude speed-up. Examples are shown for incomplete path openings, where computing times are brought from minutes to tens of milliseconds, while obtaining similar results

One-Dimensional Openings, Granulometries and Component Trees in O(1) Per Pixel

International audienceWe introduce a new, efficient and adaptable algorithm to compute openings, granulometries and the component tree for one-dimensional (1-D) signals. The algorithm requires only one scan of the signal, runs in place in per pixel, and supports any scalar data precision (integer or floating-point data). The algorithm is applied to two-dimensional images along straight lines, in arbitrary orientations. Oriented size distributions can thus be efficiently computed, and textures characterized. Extensive benchmarks are reported. They show that the proposed algorithm allows computing 1-D openings faster than existing algorithms for data precisions higher than 8 bits, and remains competitive with respect to the algorithm proposed by Van Droogenbroeck when dealing with 8-bit images. When computing granulometries, the new algorithm runs faster than any other method of the state of the art. Moreover, it allows efficient computation of 1-D component trees

Vliv elicitinů na změny proteomu tabáku

Title in English: Elicitins impact on the proteome of tobacco Abstract in English: Cryptogein is a proteinaceous elicitor secreted by an oomycete Phytophthora cryptogea that can induce resistance to P. parasitica in tobacco plants. On the basis of previous computer modeling, a series of cryptogein mutants was prepared with altered abilities to bind sterols, phospholipids or both. The sterol binding and phospholipid transfer activities corresponded to expectations based on the structural data reported previously. Induction of synthesis of reactive oxygen species (ROS) in tobacco cells suspension and proteomic analysis of intercellular fluid changes in tobacco leaves triggered by these mutant elicitins were not proportional to their ability to bind or transfer sterols and phospholipids. However, changes in the intercellular proteome corresponded to transcription levels of defense genes and resistance to P. parasitica and structure-prediction of mutants did not reveal any significant changes in protein structure. These results suggest, contrary to previous proposals, that the sterol-binding ability of cryptogein and its mutants, and the associated conformational change in the -loop, might not be principal factors in either ROS production or resistance induction. Nevertheless results support importance of...Název česky: Vliv elicitinů na změny proteomu tabáku Abstrakt česky: Kryptogein je proteinový elicitor sekretovaný oomycetou Phytophthora cryptogea. V rostlinách tabáku je schopen indukovat rezistenci vůči P. parasitica. Na základě dříve provedeného počítačového modelování byly připraveny mutantní formy kryptogeinu s alterovanou schopností vázat steroly, fosfolipidy či obojí, přičemž schopnost vazby sterolů a transferu fosfolipidů jsme ověřili i experimentálně. Úroveň indukce syntézy reaktivních forem kyslíku (ROS) v suspenzi tabákových buněk a proteomických změn v mezibuněčné tekutině listů tabáku vyvolaných těmito mutantními elicitiny nebyla úměrná jejich schopnostem vázat či transportovat steroly a fosfolipidy. Změny v intercelulárním proteomu však odpovídaly úrovním transkripce obranných genů a rezistence vůči P. parasitica, přičemž nebyly predikovány významné změny ve struktuře připravených mutantních proteinů. Naše výsledky nejsou ve shodě s dřívějšími předpoklady a naznačují, že sterol-vazebné schopnosti kryptogeinu a jeho mutantů a s nimi asociované změny konformace -smyčky nemusí být zásadními faktory řídícími produkci ROS či indukci rezistence. Výsledky nicméně podporují význam -smyčky při interakci elicitinu s vysoce afinitním vazebným místem na cytoplasmatické membráně buněk tabáku.Department of BiochemistryKatedra biochemieFaculty of SciencePřírodovědecká fakult

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

Direction-adaptive grey-level morphology. Application to 3D vascular brain imaging

International audienceSegmentation and analysis of blood vessels is an important issue in medical imaging. In 3D cerebral angiographic data, the vascular signal is however hard to accurately detect and can, in particular, be disconnected. In this article, we present a procedure utilising both linear, Hessian-based and morphological methods for blood vessel edge enhancement and reconnection. More specifically, multi-scale second-order derivative analysis is performed to detect candidate vessels as well as their orientation. This information is then fed to a spatially-variant morphological filter for reconnection and reconstruction. The result is a fast and effective vessel-reconnecting method