51 research outputs found
Balance-guaranteed optimized tree with reject option for live fish recognition
This thesis investigates the computer vision application of live fish recognition, which
is needed in application scenarios where manual annotation is too expensive, when
there are too many underwater videos. This system can assist ecological surveillance
research, e.g. computing fish population statistics in the open sea. Some pre-processing
procedures are employed to improve the recognition accuracy, and then 69 types of
features are extracted. These features are a combination of colour, shape and texture
properties in different parts of the fish such as tail/head/top/bottom, as well as
the whole fish. Then, we present a novel Balance-Guaranteed Optimized Tree with
Reject option (BGOTR) for live fish recognition. It improves the normal hierarchical
method by arranging more accurate classifications at a higher level and keeping the
hierarchical tree balanced. BGOTR is automatically constructed based on inter-class
similarities. We apply a Gaussian Mixture Model (GMM) and Bayes rule as a reject
option after the hierarchical classification to evaluate the posterior probability of being
a certain species to filter less confident decisions. This novel classification-rejection
method cleans up decisions and rejects unknown classes. After constructing the tree
architecture, a novel trajectory voting method is used to eliminate accumulated errors
during hierarchical classification and, therefore, achieves better performance. The proposed
BGOTR-based hierarchical classification method is applied to recognize the 15
major species of 24150 manually labelled fish images and to detect new species in
an unrestricted natural environment recorded by underwater cameras in south Taiwan
sea. It achieves significant improvements compared to the state-of-the-art techniques.
Furthermore, the sequence of feature selection and constructing a multi-class SVM
is investigated. We propose that an Individual Feature Selection (IFS) procedure can
be directly exploited to the binary One-versus-One SVMs before assembling the full
multiclass SVM. The IFS method selects different subsets of features for each Oneversus-
One SVM inside the multiclass classifier so that each vote is optimized to discriminate
the two specific classes. The proposed IFS method is tested on four different
datasets comparing the performance and time cost. Experimental results demonstrate
significant improvements compared to the normal Multiclass Feature Selection (MFS)
method on all datasets
Underwater Live Fish Recognition Using a Balance-Guaranteed Optimized Tree
Abstract. Live fish recognition in the open sea is a challenging multiclass classification task. We propose a novel method to recognize fish in an unrestricted natural environment recorded by underwater cameras. This method extracts 66 types of features, which are a combination of color, shape and texture properties from different parts of the fish and reduce the feature dimensions with forward sequential feature selection (FSFS) procedure. The selected features of the FSFS are used by an SVM. We present a Balance-Guaranteed Optimized Tree (BGOT) to control the error accumulation in hierarchical classification and, therefore, achieve better performance. A BGOT of 10 fish species is automatically constructed using the inter-class similarities and a heuristic method. The proposed BGOT-based hierarchical classification method achieves about 4 % better accuracy compared to state-of-the-art techniques on a live fish image dataset.
Quantum entanglement and disentanglement of multi-atom systems
We present a review of recent research on quantum entanglement, with special
emphasis on entanglement between single atoms, processing of an encoded
entanglement and its temporary evolution. Analysis based on the density matrix
formalism are described. We give a simple description of the entangling
procedure and explore the role of the environment in creation of entanglement
and in disentanglement of atomic systems. A particular process we will focus on
is spontaneous emission, usually recognized as an irreversible loss of
information and entanglement encoded in the internal states of the system. We
illustrate some certain circumstances where this irreversible process can in
fact induce entanglement between separated systems. We also show how
spontaneous emission reveals a competition between the Bell states of a two
qubit system that leads to the recently discovered "sudden" features in the
temporal evolution of entanglement. An another problem illustrated in details
is a deterministic preparation of atoms and atomic ensembles in long-lived
stationary squeezed states and entangled cluster states. We then determine how
to trigger the evolution of the stable entanglement and also address the issue
of a steered evolution of entanglement between desired pairs of qubits that can
be achieved simply by varying the parameters of a given system.Comment: Review articl
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