We describe a novel probabilistic framework for real-time tracking of multiple objects from combined depth-colour imagery. Object shape is represented implicitly using 3D signed distance functions. ...Probabilistic generative models based on these functions are developed to account for the observed RGB-D imagery, and tracking is posed as a maximum a posteriori problem. We present first a method suited to tracking a single rigid 3D object, and then generalise this to multiple objects by combining distance functions into a shape union in the frame of the camera. This second model accounts for similarity and proximity between objects, and leads to robust real-time tracking without recourse to bolt-on or ad-hoc collision detection.
Figure‐ground segmentation from bounding box input, provided either automatically or manually, has been extremely popular in the last decade and influenced various applications. A lot of research has ...focused on high‐quality segmentation, using complex formulations which often lead to slow techniques, and often hamper practical usage. In this paper we demonstrate a very fast segmentation technique which still achieves very high quality results. We propose to replace the time consuming iterative refinement of global colour models in traditional GrabCut formulation by a densely connected crf. To motivate this decision, we show that a dense crf implicitly models unnormalized global colour models for foreground and background. Such relationship provides insightful analysis to bridge between dense crf and GrabCut functional. We extensively evaluate our algorithm using two famous benchmarks. Our experimental results demonstrated that the proposed algorithm achieves an order of magnitude (10×) speed‐up with respect to the closest competitor, and at the same time achieves a considerably higher accuracy.
We propose a novel nonlinear, probabilistic and variational method for adding shape information to level set-based segmentation and tracking. Unlike previous work, we represent shapes with elliptic ...Fourier descriptors and learn their lower dimensional latent space using Gaussian Process Latent Variable Models. Segmentation is done by a nonlinear minimisation of an image-driven energy function in the learned latent space. We combine it with a 2D pose recovery stage, yielding a single, one shot, optimisation of both shape and pose. We demonstrate the performance of our method, both qualitatively and quantitatively, with multiple images, video sequences and latent spaces, capturing both shape kinematics and object class variance.
Shared shape spaces Prisacariu, V. A.; Reid, I.
2011 International Conference on Computer Vision,
2011-Nov.
Conference Proceeding
We propose a method for simultaneous shape-constrained segmentation and parameter recovery. The parameters can describe anything from 3D shape to 3D pose and we place no restriction on the topology ...of the shapes, i.e. they can have holes or be made of multiple parts. We use Shared Gaussian Process Latent Variable Models to learn multimodal shape-parameter spaces. These allow non-linear embeddings of the high-dimensional shape and parameter spaces in low dimensional spaces in a fully probabilistic manner. We propose a method for exploring the multimodality in the joint space in an efficient manner, by learning a mapping from the latent space to a space that encodes the similarity between shapes. We further extend the SGP-LVM to a model that makes use of a hierarchy of embeddings and show that this yields faster convergence and greater accuracy over the standard non-hierarchical embedding. Shapes are represented implicitly using level sets, and inference is made tractable by compressing the level set embedding functions with discrete cosine transforms. We show state of the art results in various fields, ranging from pose recovery to gaze tracking and to monocular 3D reconstruction.
Flying on Archimedes principles carried out with propulsion systems has never been abandoned; the current stages prove the maturity of this modern aeronautics sub-domain. The references highlight the ...importance of airships, and specialists in the field offer new opportunities in terms of use and capabilities of this type of aircraft in modern airspace. Military Air Force missions have reconfirmed the importance and efficiency of this type of aircraft. The article includes an aerodynamic analysis of quasi-stationary flight and low speeds in the case of inflatable airships type UAV in different atmospheric conditions, which analyze the influences of flight conditions on the performances of this type of aircraft used for data acquisition in areas of interest.
Solar energy represents a renewable energy which is one of the most expected to breakthrough in the next years in many application fields, as a heating source. It is expected that we can use solar ...energy in order to activate special materials, sensitive to heat variation, like shape memory alloys. Shape memory alloys present an increasing number of applications in the last years. Solar heat is free and endless on short time (hundreds of years) so it represents an ideal source of energy. Using a proper mirror-concentrator system, at a reduced scale for temperature lower than 500-600 °C, we can activate any type of shape memory element with different temperatures, rates of heating or maintaining periods of the heat using the shutter aperture. We analyse the behaviour of a shape memory alloy based on copper at different heating cycles in regime of shocks till 300 respectively 600 °C (with different heating rates, till 120°C/ms, excepting first cycle). The temperature variation was registered and analysed using Graphtec Corporation equipment and Origin software.
Unmanned aerial vectors have become a mature technology that requires multidisciplinary and trans-disciplinary approaches based on airline typology. The technological level implemented has proven to ...be independent of the size of the air vector, which takes into account the missions, costs and limitations of the system. The article wishes to summarize the information about the automatic open-source APM 2.6 pilot for the construction and connection, programming and operation of the sensors used.
Beside biocompatible classic metallic materials, biodegradable metals (BMs) like alloys of zinc (Zn-based) present a high potential as an alternative solution for permanent implants elements ...generally being applied for fractures restorations or other similar medical conditions. An experimental alloy, ZnMgY, was obtained using an induction furnace from high purity materials (Zn: 99,995 and master alloy MgY: 65-35 wt%), in Argon atmosphere. Microstructure of the alloy (after mechanical grinding and polish plus chemical etching) and chemical insights (before chemical etching) were taken using optical microscope (Zeiss+Motic digital camera for image acquisition) scanning electron microscope (SEM VegaTescan LMH II, SE, 30 kV, 16 mm WD) and dispersive energy spectroscopy (EDS Bruker, PB ZAF, Automatic mode of analyze, Point and Mapping features). The experimental alloy was five times re-melted in the induction furnace using a ceramic crucible. The experimental alloys present a good chemical homogenization without porosity, metallic inclusions or segregation.
Analysis performances of UAV airships Prisacariu, V; Cioacă, C; Boşcoianu, M
Scientific Bulletin ("Mircea cel Bătrân" Naval Academy),
01/2018, Letnik:
21, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Flying on Archimedes principles carried out with propulsion systems has never been abandoned; the current stages prove the maturity of this modern aeronautics sub-domain. The references highlight the ...importance of airships, and specialists in the field offer new opportunities in terms of use and capabilities of this type of aircraft in modern airspace. Military Air Force missions have reconfirmed the importance and efficiency of this type of aircraft. The article includes an aerodynamic analysis of quasi-stationary flight and low speeds in the case of inflatable airships type UAV in different atmospheric conditions, which analyze the influences of flight conditions on the performances of this type of aircraft used for data acquisition in areas of interest.
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