171 research outputs found
Embedding based on function approximation for large scale image search
The objective of this paper is to design an embedding method that maps local
features describing an image (e.g. SIFT) to a higher dimensional representation
useful for the image retrieval problem. First, motivated by the relationship
between the linear approximation of a nonlinear function in high dimensional
space and the stateof-the-art feature representation used in image retrieval,
i.e., VLAD, we propose a new approach for the approximation. The embedded
vectors resulted by the function approximation process are then aggregated to
form a single representation for image retrieval. Second, in order to make the
proposed embedding method applicable to large scale problem, we further derive
its fast version in which the embedded vectors can be efficiently computed,
i.e., in the closed-form. We compare the proposed embedding methods with the
state of the art in the context of image search under various settings: when
the images are represented by medium length vectors, short vectors, or binary
vectors. The experimental results show that the proposed embedding methods
outperform existing the state of the art on the standard public image retrieval
benchmarks.Comment: Accepted to TPAMI 2017. The implementation and precomputed features
of the proposed F-FAemb are released at the following link:
http://tinyurl.com/F-FAem
Supervised Hashing with End-to-End Binary Deep Neural Network
Image hashing is a popular technique applied to large scale content-based
visual retrieval due to its compact and efficient binary codes. Our work
proposes a new end-to-end deep network architecture for supervised hashing
which directly learns binary codes from input images and maintains good
properties over binary codes such as similarity preservation, independence, and
balancing. Furthermore, we also propose a new learning scheme that can cope
with the binary constrained loss function. The proposed algorithm not only is
scalable for learning over large-scale datasets but also outperforms
state-of-the-art supervised hashing methods, which are illustrated throughout
extensive experiments from various image retrieval benchmarks.Comment: Accepted to IEEE ICIP 201
Real-Time 6DOF Pose Relocalization for Event Cameras with Stacked Spatial LSTM Networks
We present a new method to relocalize the 6DOF pose of an event camera solely
based on the event stream. Our method first creates the event image from a list
of events that occurs in a very short time interval, then a Stacked Spatial
LSTM Network (SP-LSTM) is used to learn the camera pose. Our SP-LSTM is
composed of a CNN to learn deep features from the event images and a stack of
LSTM to learn spatial dependencies in the image feature space. We show that the
spatial dependency plays an important role in the relocalization task and the
SP-LSTM can effectively learn this information. The experimental results on a
publicly available dataset show that our approach generalizes well and
outperforms recent methods by a substantial margin. Overall, our proposed
method reduces by approx. 6 times the position error and 3 times the
orientation error compared to the current state of the art. The source code and
trained models will be released.Comment: 7 pages, 5 figure
Selective Deep Convolutional Features for Image Retrieval
Convolutional Neural Network (CNN) is a very powerful approach to extract
discriminative local descriptors for effective image search. Recent work adopts
fine-tuned strategies to further improve the discriminative power of the
descriptors. Taking a different approach, in this paper, we propose a novel
framework to achieve competitive retrieval performance. Firstly, we propose
various masking schemes, namely SIFT-mask, SUM-mask, and MAX-mask, to select a
representative subset of local convolutional features and remove a large number
of redundant features. We demonstrate that this can effectively address the
burstiness issue and improve retrieval accuracy. Secondly, we propose to employ
recent embedding and aggregating methods to further enhance feature
discriminability. Extensive experiments demonstrate that our proposed framework
achieves state-of-the-art retrieval accuracy.Comment: Accepted to ACM MM 201
Probabilistic task modelling for meta-learning
We propose probabilistic task modelling -- a generative probabilistic model
for collections of tasks used in meta-learning. The proposed model combines
variational auto-encoding and latent Dirichlet allocation to model each task as
a mixture of Gaussian distribution in an embedding space. Such modelling
provides an explicit representation of a task through its task-theme mixture.
We present an efficient approximation inference technique based on variational
inference method for empirical Bayes parameter estimation. We perform empirical
evaluations to validate the task uncertainty and task distance produced by the
proposed method through correlation diagrams of the prediction accuracy on
testing tasks. We also carry out experiments of task selection in meta-learning
to demonstrate how the task relatedness inferred from the proposed model help
to facilitate meta-learning algorithms.Comment: Accepted at UAI 202
- …