Associative Embedding for Game-Agnostic Team Discrimination

Assigning team labels to players in a sport game is not a trivial task when no prior is known about the visual appearance of each team. Our work builds on a Convolutional Neural Network (CNN) to learn a descriptor, namely a pixel-wise embedding vector, that is similar for pixels depicting players from the same team, and dissimilar when pixels correspond to distinct teams. The advantage of this idea is that no per-game learning is needed, allowing efficient team discrimination as soon as the game starts. In principle, the approach follows the associative embedding framework introduced in arXiv:1611.05424 to differentiate instances of objects. Our work is however different in that it derives the embeddings from a lightweight segmentation network and, more fundamentally, because it considers the assignment of the same embedding to unconnected pixels, as required by pixels of distinct players from the same team. Excellent results, both in terms of team labelling accuracy and generalization to new games/arenas, have been achieved on panoramic views of a large variety of basketball games involving players interactions and occlusions. This makes our method a good candidate to integrate team separation in many CNN-based sport analytics pipelines.Comment: Published in CVPR 2019 workshop Computer Vision in Sports, under the name "Associative Embedding for Team Discrimination" (http://openaccess.thecvf.com/content_CVPRW_2019/html/CVSports/Istasse_Associative_Embedding_for_Team_Discrimination_CVPRW_2019_paper.html

Broadband antireflection coatings for visible and infrared ranges

International audienceAntireflection coatings are critical elements for space applications as they will influence the overall performances of optical systems. They are among the most classical elements that are produced with optical coatings but remain a challenge when high performances are required. In this paper, we present some recent results based on thin film technology for the production of antireflection coatings dedicated to visible, near-IR and mid-IR spectral ranges. We first present a theoretical and experimental study of broadband antireflection coatings for [400-1100] nm spectral range. We then show antireflection coatings covering the [1.5-15] µm range. Experimental demonstrations and limitations are presented

Analysis over vision-based models for pedestrian action anticipation

Anticipating human actions in front of autonomous vehicles is a challenging task. Several papers have recently proposed model architectures to address this problem by combining multiple input features to predict pedestrian crossing actions. This paper focuses specifically on using images of the pedestrian's context as an input feature. We present several spatio-temporal model architectures that utilize standard CNN and Transformer modules to serve as a backbone for pedestrian anticipation. However, the objective of this paper is not to surpass state-of-the-art benchmarks but rather to analyze the positive and negative predictions of these models. Therefore, we provide insights on the explainability of vision-based Transformer models in the context of pedestrian action prediction. We will highlight cases where the model can achieve correct quantitative results but falls short in providing human-like explanations qualitatively, emphasizing the importance of investing in explainability for pedestrian action anticipation problems

La capacité d’absorption, l’élément clé dans la compréhension de la relation entre information et innovation : Le cas des PME du Congo-Brazzaville

Plusieurs études rappellent que l’innovation dans les PME s’explique avant tout par l’apport systématique de l’information le plus souvent informelle provenant notamment des clients, des fournisseurs, des concurrents et de diverses sources plus formelles comme les revues d’affaires ou les foires industrielles. On peut toutefois favoriser celle-ci par une meilleure capacité de ces organisations à cibler et à transformer l’information en connaissance, en particulier en organisant mieux la veille et en améliorant la capacité d’absorption et de transformation de l’information.Dans une enquête exploratoire effectuée auprès d’une quarantaine de PME de trois secteurs industriels au Congo-Brazzaville et en tenant compte des caractéristiques d’un pays en développement, nous montrons que la relation entre les sources d’information, la capacité d’absorption et l’innovation joue autant que dans les pays industrialisés. En particulier, le niveau de formation de la direction et de quelques employés clefs semble constituer la variable la plus importante pour expliquer cette relation.Several studies point out that innovation in SMEs is explained primarily by providing systematic information, mostly informal, from customers, suppliers, competitors and various other more formal sources such as business magazines or industrial fairs. However, one may favour innovation through an improved capacity to target and transform information into knowledge, especially in regard to business intelligence gathering, and by improving the capacity to absorb and process information.In an exploratory survey conducted among forty SMEs in three industrial sectors in Congo-Brazzaville, and taking into account the characteristics of a developing country, we show that the relationship between sources of information, absorptive capacity and innovation is as strong as in industrialized countries. In particular, the training level of management and key employees appears to be the most important variable to explain this relationship.Varios estudios señalan que la innovación en las PyMEs se explica principalmente por el suministro de información sistemática en su mayoría informal, procediendo de clientes, proveedores, competidores y varias fuentes más oficiales, como las revistas de negocios o ferias industriales. Sin embargo, podemos promover a través de una mayor capacidad de estas organizaciones para seleccionar y transformar información en conocimiento, especialmente en la organización mejor de vigilia, y por la mejora de la absorción y procesamiento de información.En una encuesta exploratoria realizada entre los cuarenta PyMEs de tres sectores industriales en Congo-Brazzaville, y teniendo en cuenta las características de un país en desarrollo, mostramos que la relación entre las fuentes de información, la capacidad de la absorción y la innovación es tanto como en los países industrializados. En particular, el nivel de formación de gestión y de algunos empleados clave parece ser la variable más importante para explicar esta relación.Mehrere Studien weisen darauf hin, dass Innovationen in KMU in erster Linie durch den systematischen Zufluss von Informationen aus informellen Quellen (Kunden, Lieferanten, Konkurrenten) sowie von Informationen formelleren Ursprungs (Fachmagazine, industrielle Messen) erklärbar sind. Der informative Nutzen zeigt sich bei den Unternehmen in einer verbesserten Kapazität, die relevanten Informationen zu filtern und in Wissen umzuwandeln und vor allem in einer gesteigerten Fähigkeit Informationen zu absorbieren und zu überwachen.In einer explorativen Studie bei rund 40 KMU aus drei Industriesektoren im Kongo-Brazzaville und unter Berücksichtigung der Eigenheiten eines Entwicklungslandes, konnte aufgezeigt werden, dass der Zusammenhang zwischen Informationsquellen, Absorptionsfähigkeit und Innovation, genauso wie in Industrieländern, eine Rolle spielt. Die Ausbildung des Managements sowie diejenige einiger Schlüsselmitarbeiter scheint dabei in diesem Zusammenspiel eine besondere Rolle zu spielen

Fast interrogation wavelength tuning for all-optical photoacoustic imaging

Optical detection of ultrasound for photoacoustic imaging provides large bandwidth and high sensitivity at high acoustic frequencies. Higher spatial resolutions can therefore be achieved using Fabry-P\'erot cavity sensors, as compared to conventional piezoelectric detection. However, fabrication constraints during deposition of the sensing polymer layer require a precise control of the interrogation beam wavelength to provide optimal sensitivity. This is commonly achieved by employing slowly tunable narrowband lasers as interrogation sources, hence limiting the acquisition speed. We propose instead to use a broadband source and a fast tunable acousto-optic filter to adjust the interrogation wavelength at each pixel within a few microseconds. We demonstrate the validity of this approach by performing photoacoustic imaging with a highly inhomogeneous Fabry-P\'erot sensor.Comment: 9 pages, 4 figure

High performance thin-film optical filters with stress compensation

International audienceWe present a thorough description of high performance thin-film optical filters with high flatness. These components can combine several tens or hundreds of layers and are manufactured using plasma-assisted reactive magnetron sputtering. Stress compensation is achieved using dual side coatings with appropriate spectral function. Examples of highly reflecting mirrors at 515 nm with 15 nm flatness peak-to-valley over up to 75 mm diameter aperture, narrow bandpass filters and filters with broadband controlled transmission are described

The Late Palaeozoic glaciation subsurface record, Chaco Basin (Bolivia)

Late Palaeozoic glaciation is the longest of the Phanerozoic era. It is recorded in numerous Gondwanian basins, some having a high petroleum potential like the Chaco Basin. In this basin, the quality of the available seismic, well and outcrop data permits to characterise the Late Palaeozoic glacial record. Palaeovalleys >500 m deep and ~7 km wide have here been analysed. Focusing on the glaciogenic Carboniferous deposits, the seismic data with well-ties and their outcrop analogues provide new sedimentological insights. The palaeovalley infill is imaged as a chaotic seismic facies overlain by an aggrading-prograding prism, interpreted as tillites covered by a fluvio-deltaic system respectively. Tillites form both under the ice and during rapid ice recession whereas fluvio-deltaic systems can only originate from a stable ice margin and last until the ice sheets withdraw inland. These two depositional modes are repeated several times generating the progressive burial of the Carboniferous palaeovalleys. This succession of erosions and fills records major glacial stages containing a series of glacial and interglacial phases from the Late Devonian to the Early Permian. Depicting the Late Palaeozoic glacial history of the Chaco Basin seems crucial for the localisation of potential good reservoirs