A novel method, µ-MAR, able to both coarse and fine register 3D point sets.The method overcomes noisy data problem using model based planes registration.µ-MAR iteratively registers a 3D markers around the object to be reconstructed.It uses a variant of the multi-view registration with subsets of data.Transformations to register the markers allow to reconstruct the object accurately. Many applications including object reconstruction, robot guidance, and. scene mapping require the registration of multiple views from a scene to generate a complete geometric and appearance model of it. In real situations, transformations between views are unknown and it is necessary to apply expert inference to estimate them. In the last few years, the emergence of low-cost depth-sensing cameras has strengthened the research on this topic, motivating a plethora of new applications. Although they have enough resolution and accuracy for many applications, some situations may not be solved with general state-of-the-art registration methods due to the signal-to-noise ratio (SNR) and the resolution of the data provided. The problem of working with low SNR data, in general terms, may appear in any 3D system, then it is necessary to propose novel solutions in this aspect. In this paper, we propose a method, µ-MAR, able to both coarse and fine register sets of 3D points provided by low-cost depth-sensing cameras, despite it is not restricted to these sensors, into a common coordinate system. The method is able to overcome the noisy data problem by means of using a model-based solution of multiplane registration. Specifically, it iteratively registers 3D markers composed by multiple planes extracted from points of multiple views of the scene. As the markers and the object of interest are static in the scenario, the transformations obtained for the markers are applied to the object in order to reconstruct it. Experiments have been performed using synthetic and real data. The synthetic data allows a qualitative and quantitative evaluation by means of visual inspection and Hausdorff distance respectively. The real data experiments show the performance of the proposal using data acquired by a Primesense Carmine RGB-D sensor. The method has been compared to several state-of-the-art methods. The results show the good performance of the µ-MAR to register objects with high accuracy in presence of noisy data outperforming the existing methods.

µ-MAR

2004 IUCN red list of threatened species : a global species assessment

(2000). Management of Sharks and Their Relatives (Elasmobranchii) Fisheries: Vol. 25, No. 3, pp. 9-13.

Management of Sharks and Their Relatives (Elasmobranchii)

Relatively few marine fishes have been assessed under World Conservation Union criteria, yet it is believed that marine fish extinction rates have been underestimated by one order of magnitude (McKinney 1999). Given the paucity of data required for traditional assessment methods, we explored the use of poten- tial correlates of extinction vulnerability to prioritize species for conservation assessment. We focused on the world's 230 species of skates and rays (Rajidae) because they have been identified as one of the most vulner- able groups of marine fishes. We searched for all documented cases of local extinction and compiled a data- base of body size and latitudinal and depth ranges for all species for which data were available. We found that species that have disappeared from substantial parts of their ranges ("locally extinct") have large body sizes compared with all other skates, but that latitudinal and depth ranges were similar to those of other spe- cies. The body size correlate may be due to higher mortality rates and correlations with life-history parame- ters such as late age at maturity. We used the locally extinct species that had the smallest size or ranges as benchmarks to generate lists of other species that may be vulnerable. Body size generated the smallest species list (7), excluding the known local extinctions, compared with lists generated by size of latitudinal (150) or depth range (63). Body size was the only trait that correctly identified the known local extinctions, suggesting that it is more useful than range sizes for identifying potentially vulnerable fishes. This provides a simple, ob- jective method of prioritizing species for further assessment, which complements direct methods that are more data-intensive and time-consuming.

/pdf/predicting-extinction-vulnerability-in-skates-lsgah132wd.pdf

Predicting Extinction Vulnerability in Skates

We compared life-history traits and extinction risk of chondrichthyans (sharks, rays and chimaeras), a group of high conservation concern, from the three major marine habitats (continental shelves, open ocean and deep sea), controlling for phylogenetic correlation. Deep-water chondrichthyans had a higher age at maturity and longevity, and a lower growth completion rate than shallow-water species. The average fishing mortality needed to drive a deep-water chondrichthyan species to extinction (Fextinct) was 38‐58% of that estimated for oceanic and continental shelf species, respectively. Mean values of Fextinct were 0.149, 0.250 and 0.368 for deep-water, oceanic and continental shelf species, respectively. Reproductive mode was an important determinant of extinction risk, while body size had a weak effect on extinction risk. As extinction risk was highly correlated with phylogeny, the loss of species will be accompanied by a loss of phylogenetic diversity. Conservation priority should not be restricted to large species, as is usually suggested, since many small species, like those inhabiting the deep ocean, are also highly vulnerable to extinction. Fishing mortality of deep-water chondrichthyans already exploited should be minimized, and new deep-water fisheries affecting chondrichthyans should be prevented.

/pdf/the-importance-of-habitat-and-life-history-to-extinction-1blvfl9z45.pdf

The importance of habitat and life history to extinction risk in sharks, skates, rays and chimaeras

Challenges and Priorities in Shark and Ray Conservation.

Sharks and their relatives, the rays and chimaeras, are the diverse group of cartilaginous fishes that have evolved over 400 million years. Historically considered of low economic value to large-scale fisheries, today many of these fishes have become the target of directed commercial and recreational fisheries around the world, and they are increasingly taken in the by-catch of fisheries targeting other species. This report emphasizes the widely-acknowledged need to improve shark fishery monitoring, expand biological research and take management action. It serves as an introduction to the ecology, status and conservation of the sharks and their relatives for a general audience. Shark fisheries can only be managed sustainably, and shark populations remain viable, with the introduction of new conservation and management initiatives.

Sharks and their Relatives: Ecology And Conservation

Les requins et autres poissons cartilagineux : écologie et conservation

Global Priorities for Conserving Sharks and Rays

/pdf/chondrichthyans-of-the-western-indian-ocean-biodiversity-c5cdhdeu.pdf

Amie Bräutigam

Papers

Challenges and Priorities in Shark and Ray Conservation.

Sharks and their Relatives: Ecology And Conservation

Les requins et autres poissons cartilagineux : écologie et conservation

Global Priorities for Conserving Sharks and Rays

Chondrichthyans of the Western Indian Ocean: Biodiversity, Fisheries and Trade, Management and Conservation