4,556 research outputs found
Efficient Semidefinite Spectral Clustering via Lagrange Duality
We propose an efficient approach to semidefinite spectral clustering (SSC),
which addresses the Frobenius normalization with the positive semidefinite
(p.s.d.) constraint for spectral clustering. Compared with the original
Frobenius norm approximation based algorithm, the proposed algorithm can more
accurately find the closest doubly stochastic approximation to the affinity
matrix by considering the p.s.d. constraint. In this paper, SSC is formulated
as a semidefinite programming (SDP) problem. In order to solve the high
computational complexity of SDP, we present a dual algorithm based on the
Lagrange dual formalization. Two versions of the proposed algorithm are
proffered: one with less memory usage and the other with faster convergence
rate. The proposed algorithm has much lower time complexity than that of the
standard interior-point based SDP solvers. Experimental results on both UCI
data sets and real-world image data sets demonstrate that 1) compared with the
state-of-the-art spectral clustering methods, the proposed algorithm achieves
better clustering performance; and 2) our algorithm is much more efficient and
can solve larger-scale SSC problems than those standard interior-point SDP
solvers.Comment: 13 page
Fingerprint Recognition Using Translation Invariant Scattering Network
Fingerprint recognition has drawn a lot of attention during last decades.
Different features and algorithms have been used for fingerprint recognition in
the past. In this paper, a powerful image representation called scattering
transform/network, is used for recognition. Scattering network is a
convolutional network where its architecture and filters are predefined wavelet
transforms. The first layer of scattering representation is similar to sift
descriptors and the higher layers capture higher frequency content of the
signal. After extraction of scattering features, their dimensionality is
reduced by applying principal component analysis (PCA). At the end, multi-class
SVM is used to perform template matching for the recognition task. The proposed
scheme is tested on a well-known fingerprint database and has shown promising
results with the best accuracy rate of 98\%.Comment: IEEE Signal Processing in Medicine and Biology Symposium, 201
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A niching memetic algorithm for simultaneous clustering and feature selection
Clustering is inherently a difficult task, and is made even more difficult when the selection of relevant features is also an issue. In this paper we propose an approach for simultaneous clustering and feature selection using a niching memetic algorithm. Our approach (which we call NMA_CFS) makes feature selection an integral part of the global clustering search procedure and attempts to overcome the problem of identifying less promising locally optimal solutions in both clustering and feature selection, without making any a priori assumption about the number of clusters. Within the NMA_CFS procedure, a variable composite representation is devised to encode both feature selection and cluster centers with different numbers of clusters. Further, local search operations are introduced to refine feature selection and cluster centers encoded in the chromosomes. Finally, a niching method is integrated to preserve the population diversity and prevent premature convergence. In an experimental evaluation we demonstrate the effectiveness of the proposed approach and compare it with other related approaches, using both synthetic and real data
Optimal Generation of Iris Codes for Iris Recognition
The calculation of binary iris codes from feature values (e.g. the result of Gabor transform) is a key step in iris recognition systems. Traditional binarization method based on the sign of feature values has achieved very promising performance. However, currently, little research focuses on a deeper insight into this binarization method to produce iris codes. In this paper, we illustrate the iris code calculation from the perspective of optimization. We demonstrate that the traditional iris code is the solution of an optimization problem which minimizes the distance between the feature values and iris codes. Furthermore, we show that more effective iris codes can be obtained by adding terms to the objective function of this optimization problem. We investigate two additional objective terms. The first objective term exploits the spatial relationships of the bits in different positions of an iris code. The second objective term mitigates the influence of less reliable bits in iris codes. The two objective terms can be applied to the optimization problem individually, or in a combined scheme. We conduct experiments on four benchmark datasets with varying image quality. The experimental results demonstrate that the iris code produced by solving the optimization problem with the two additional objective terms achieves a generally improved performance in comparison to the traditional iris code calculated by binarizing feature values based on their signs
Influence of segmentation on deep iris recognition performance
Despite the rise of deep learning in numerous areas of computer vision and
image processing, iris recognition has not benefited considerably from these
trends so far. Most of the existing research on deep iris recognition is
focused on new models for generating discriminative and robust iris
representations and relies on methodologies akin to traditional iris
recognition pipelines. Hence, the proposed models do not approach iris
recognition in an end-to-end manner, but rather use standard heuristic iris
segmentation (and unwrapping) techniques to produce normalized inputs for the
deep learning models. However, because deep learning is able to model very
complex data distributions and nonlinear data changes, an obvious question
arises. How important is the use of traditional segmentation methods in a deep
learning setting? To answer this question, we present in this paper an
empirical analysis of the impact of iris segmentation on the performance of
deep learning models using a simple two stage pipeline consisting of a
segmentation and a recognition step. We evaluate how the accuracy of
segmentation influences recognition performance but also examine if
segmentation is needed at all. We use the CASIA Thousand and SBVPI datasets for
the experiments and report several interesting findings.Comment: 6 pages, 3 figures, 3 tables, submitted to IWBF 201
Mask-guided Style Transfer Network for Purifying Real Images
Recently, the progress of learning-by-synthesis has proposed a training model
for synthetic images, which can effectively reduce the cost of human and
material resources. However, due to the different distribution of synthetic
images compared with real images, the desired performance cannot be achieved.
To solve this problem, the previous method learned a model to improve the
realism of the synthetic images. Different from the previous methods, this
paper try to purify real image by extracting discriminative and robust features
to convert outdoor real images to indoor synthetic images. In this paper, we
first introduce the segmentation masks to construct RGB-mask pairs as inputs,
then we design a mask-guided style transfer network to learn style features
separately from the attention and bkgd(background) regions and learn content
features from full and attention region. Moreover, we propose a novel
region-level task-guided loss to restrain the features learnt from style and
content. Experiments were performed using mixed studies (qualitative and
quantitative) methods to demonstrate the possibility of purifying real images
in complex directions. We evaluate the proposed method on various public
datasets, including LPW, COCO and MPIIGaze. Experimental results show that the
proposed method is effective and achieves the state-of-the-art results.Comment: arXiv admin note: substantial text overlap with arXiv:1903.0582
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