Speed Invariant Time Surface for Learning to Detect Corner Points with Event-Based Cameras

We propose a learning approach to corner detection for event-based cameras that is stable even under fast and abrupt motions. Event-based cameras offer high temporal resolution, power efficiency, and high dynamic range. However, the properties of event-based data are very different compared to standard intensity images, and simple extensions of corner detection methods designed for these images do not perform well on event-based data. We first introduce an efficient way to compute a time surface that is invariant to the speed of the objects. We then show that we can train a Random Forest to recognize events generated by a moving corner from our time surface. Random Forests are also extremely efficient, and therefore a good choice to deal with the high capture frequency of event-based cameras ---our implementation processes up to 1.6Mev/s on a single CPU. Thanks to our time surface formulation and this learning approach, our method is significantly more robust to abrupt changes of direction of the corners compared to previous ones. Our method also naturally assigns a confidence score for the corners, which can be useful for postprocessing. Moreover, we introduce a high-resolution dataset suitable for quantitative evaluation and comparison of corner detection methods for event-based cameras. We call our approach SILC, for Speed Invariant Learned Corners, and compare it to the state-of-the-art with extensive experiments, showing better performance.Comment: 8 pages, 7 figures, accepted at CVPR 201

Endoscopic mucosal resection with anchoring of the snare tip: multicenter retrospective evaluation of effectiveness and safety

International audienc

The Inter-temporal relationship between Risk, Capital and Efficiency: The case of Islamic and conventional banks

The paper investigates the relationship between risk, capital and efficiency for Islamic and conventional banks using a dataset spanning 14 countries over the 2000-2012 period. We use the z-score as a proxy for insolvency risk, cost efficiency is estimated via a stochastic frontier approach and capitalisation is reflected on the equity to assets ratio. An array of bank-specific, macroeconomic and market structure variables are used in a system of three equations, estimated using the seemingly unrelated regression (SUR) technique. We find that the capitalisation response to increases in insolvency risk is more pronounced for Islamic banks but has an approximately five-times smaller effect on risk mitigation compared to conventional banks. Higher cost efficiency is related to lower risk for conventional banks, but the opposite is true for Islamic banks. The link between cost efficiency and capitalisation attests to a substitutional effect for the case of conventional banks, but a complementary effect for Islamic banks. Our findings give new insights on the use of efficiency to gauge capital requirements for financial institutions and are particularly relevant for regulators and policy makers in countries where both bank types operate

Morfologia social e contextualização topográfica: a micro-história de Edoardo Grendi

Il saggio prende in considerazione il ruolo di Edoardo Grendi nella teorizzazione della proposta microstorica italiana, generalmente sconosciuto o sottostimato nel panorama accademico sudamericano

L'expérimentation contre l'arbitraire

Lepetit Bernard, Revel Jacques. L'expérimentation contre l'arbitraire. In: Annales. Économies, Sociétés, Civilisations. 47ᵉ année, N. 1, 1992. pp. 261-265