This work is settled in the framework of abstract simplicial complexes. We propose a definition of a watershed and of a collapse for maps defined on pseudomanifolds of arbitrary dimension. Through an equivalence theorem, we establish a deep link between these two notions: any watershed can be obtained by collapse iterated until idempotence, and conversely any collapse iterated until idempotence...

The watershed transform is the method of choice for image segmentation in the field of mathematical morphology. We present a critical review of several definitions of the watershed transform and the associated sequential algorithms, and discuss various issues which often cause confusion in the literature. The need to distinguish between definition, algorithm specification and algorithm implemen...

Background. The mechanism of stroke in beta-thalassemia was reported previously as cardioembolic and hypercoagulable state. However, there is no report of watershed infarct in beta-thalassemia anemia. Method. We present an adult β-thalassemia major patient with manifest asymptomatic chronic left carotid occlusion who suffered watershed infarct. Result. In the presence of asymptomatic chronic le...

The Morro Bay Watershed, located in San Luis Obispo County, California, covers more than 48,000 acres of land and discharges into Morro Bay through the Morro Bay National Estuary (MBNE). The Chorro Creek Subwatershed consists of approximately 30,000 acres of the overall watershed. The MBNE provides an ecosystem that supports a variety of wildlife, from the common sea gull to the endangered sea ...

PURPOSE To evaluate the association between the watershed zone and glaucomatous optic nerve head (ONH) damage. METHODS We performed indocyanine green fluorescence angiography with a scanning laser ophthalmoscope in 54 eyes of 27 patients with normal tension glaucoma (NTG). RESULTS We identified 7 eyes of 8 patients (14.8%) with a watershed zone not including the ONH, 32 eyes of 20 patients ...

Land use and land cover can have a significant impact on water chemistry, but the spatial scales at which landscape attributes exert a detectable influence on aquatic systems are not well known. This study quantifies the extent of the landscape influence using the proportion of wetlands in the watershed measured at different distances to predict dissolved organic carbon (DOC) concentrations in ...

In this work, we extend a common framework for graph-based image segmentation that includes the graph cuts, random walker, and shortest path optimization algorithms. Viewing an image as a weighted graph, these algorithms can be expressed by means of a common energy function with differing choices of a parameter q acting as an exponent on the differences between neighboring nodes. Introducing a ...

Based on analyzing the drawbacks existing in traditional watershed algorithms for bone removal from CTA (Computed Tomography Angiography, CTA), this paper presents an improved interactive watershed algorithm. The improved watershed algorithm is based on sorting and graded overflow of fast watershed algorithms, and the merging process of catchment basins is intervened by a merging threshold whic...

[1] This paper presents a distribution-free statistical test aimed at detecting gradual changes in the hydrological behavior of watersheds. The proposed test uses a rainfall-runoff model to identify watershed behavior over successive time periods and a resampling approach to quantify the significance of trends. The method can be applied with any model deemed suitable for the studied watershed. ...

The paper presents applications and models which are beneficial to watershed management in various areas. The intention is to inform about the current capabilities of soft computing, hydrologic analysis modules, and distributed hydrologic models, and to provide an initial guide on implementing soft computing. Watershed is not simply the hydrological unit but also socio-political-ecological enti...