60,766 research outputs found
Neighbourhood Consensus Networks
We address the problem of finding reliable dense correspondences between a
pair of images. This is a challenging task due to strong appearance differences
between the corresponding scene elements and ambiguities generated by
repetitive patterns. The contributions of this work are threefold. First,
inspired by the classic idea of disambiguating feature matches using semi-local
constraints, we develop an end-to-end trainable convolutional neural network
architecture that identifies sets of spatially consistent matches by analyzing
neighbourhood consensus patterns in the 4D space of all possible
correspondences between a pair of images without the need for a global
geometric model. Second, we demonstrate that the model can be trained
effectively from weak supervision in the form of matching and non-matching
image pairs without the need for costly manual annotation of point to point
correspondences. Third, we show the proposed neighbourhood consensus network
can be applied to a range of matching tasks including both category- and
instance-level matching, obtaining the state-of-the-art results on the PF
Pascal dataset and the InLoc indoor visual localization benchmark.Comment: In Proceedings of the 32nd Conference on Neural Information
Processing Systems (NeurIPS 2018
Neighbourhood Consensus Networks
International audienceWe address the problem of finding reliable dense correspondences between a pair of images. This is a challenging task due to strong appearance differences between the corresponding scene elements and ambiguities generated by repetitive patterns. The contributions of this work are threefold. First, inspired by the classic idea of disambiguating feature matches using semi-local constraints, we develop an end-to-end trainable convolutional neural network architecture that identifies sets of spatially consistent matches by analyzing neighbourhood consensus patterns in the 4D space of all possible correspondences between a pair of images without the need for a global geometric model. Second, we demonstrate that the model can be trained effectively from weak supervision in the form of matching and non-matching image pairs without the need for costly manual annotation of point to point correspondences. Third, we show the proposed neighbourhood consensus network can be applied to a range of matching tasks including both category- and instance-level matching, obtaining the state-of-the-art results on the PF Pascal dataset and the InLoc indoor visual localization benchmark
Correspondence Networks with Adaptive Neighbourhood Consensus
In this paper, we tackle the task of establishing dense visual
correspondences between images containing objects of the same category. This is
a challenging task due to large intra-class variations and a lack of dense
pixel level annotations. We propose a convolutional neural network
architecture, called adaptive neighbourhood consensus network (ANC-Net), that
can be trained end-to-end with sparse key-point annotations, to handle this
challenge. At the core of ANC-Net is our proposed non-isotropic 4D convolution
kernel, which forms the building block for the adaptive neighbourhood consensus
module for robust matching. We also introduce a simple and efficient
multi-scale self-similarity module in ANC-Net to make the learned feature
robust to intra-class variations. Furthermore, we propose a novel orthogonal
loss that can enforce the one-to-one matching constraint. We thoroughly
evaluate the effectiveness of our method on various benchmarks, where it
substantially outperforms state-of-the-art methods.Comment: CVPR 2020. Project page: https://ancnet.avlcode.org
Neighbourhood effects and endogeneity issues
A recent body of research suggests that the spatial structure of cities might influence the socioeconomic characteristics and outcomes of their residents. In particular, the literature on neighbourhood effects emphasizes the potential influence of the socioeconomic composition of neighbourhoods in shaping individual’s behaviours and outcomes, through social networks, peer influences or socialization effects. However, empirical work still has not reached a consensus regarding the existence and magnitude of such effects. This is mainly because the study of neighbourhood effects raises important methodological concerns that have not often been taken into account. Notably, as individuals with similar socio-economic characteristics tend to sort themselves into certain parts of the city, the estimation of neighbourhood effects raises the issue of location choice endogeneity. Indeed, it is difficult to distinguish between neighbourhood effects and correlated effects, i.e. similarities in behaviours and outcomes arising from individuals having similar characteristics. This problem, if not dequately corrected for, may yield biased results. In the first part of this paper, neighbourhood effects are defined and some methodological problems involved in measuring such effects are identified. Particular attention is paid to the endogeneity issue, giving a formal definition of the problem and reviewing the main methods that have been used in the literature to try to solve it. The second part is devoted to an empirical illustration of the study of neighbourhood effects, in the case of labour-market outcomes of young adults in Brussels. The effect of living in a deprived neighbourhood on the unemployment probability of young adults residing in Brussels is estimated using logistic regressions. The endogeneity of neighbourhood is addressed by restricting the sample to young adults residing with their parents. Then, a ensitivity analysis is used to assess the robustness of the results to the presence of both observed and unobserved parental covariates.neighbourhood effects, endogeneity, self-selection, sensitivity analysis, Brussels
The Social Capital of Cohousing Communities
This article aims to discuss the possibility that cohousing communities might combine both civil engagement and governance systems in order to simultaneously generate three forms of social capital: bonding, bridging, and linking social capitals. Cohousing communities intend to create a ‘self-sufficient micro-cosmos’, but struggle against the relationships of ‘anonymous’ neighbourhood. Cohousers build their bonding social capital through the creation of a supportive (formal and informal) network within the community; while at the same time they develop bridging social capital when they try to integrate with the wider context, by organizing activities and making available spaces towards the outside. Finally, when cohousers try to collaborate with external partners (e.g. non-profit organizations and public institutions) they build linking social capital in relation to the ideas, information and advantages obtained through the collaboration with these institutions
Distributed Parameter Estimation in Probabilistic Graphical Models
This paper presents foundational theoretical results on distributed parameter
estimation for undirected probabilistic graphical models. It introduces a
general condition on composite likelihood decompositions of these models which
guarantees the global consistency of distributed estimators, provided the local
estimators are consistent
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