Incremental Laplacian eigenmaps by preserving adjacent information between
data points
Peng Jia
a
, Junsong Yin
b
, Xinsheng Huang
a
, Dewen Hu
a,
*
a
Department of Automatic Control, College of Mechatronics and Automation, National University of Defense Technology, Changsha, Hunan 410073, China
b
Beijing Institute of Electronic System Engineering, 100141, China
article info
Article history:
Received 13 May 2008
Received in revised form 22 June 2009
Available online xxxx
Communicated by M.A. Girolami
Keywords:
Laplacian eigenmaps
Incremental learning
Locally linear construction
Nonlinear dimensionality reduction
abstract
Traditional nonlinear manifold learning methods have achieved great success in dimensionality reduc-
tion and feature extraction, most of which are batch modes. However, if new samples are observed,
the batch methods need to be calculated repeatedly, which is computationally intensive, especially when
the number or dimension of the input samples are large. This paper presents incremental learning algo-
rithms for Laplacian eigenmaps, which computes the low-dimensional representation of data set by opti-
mally preserving local neighborhood information in a certain sense. Sub-manifold analysis algorithm
together with an alternative formulation of linear incremental method is proposed to learn the new sam-
ples incrementally. The locally linear reconstruction mechanism is introduced to update the existing
samples’ embedding results. The algorithms are easy to be implemented and the computation procedure
is simple. Simulation results testify the efficiency and accuracy of the proposed algorithms.
Ó 2009 Elsevier B.V. All rights reserved.
1. Introduction
In pattern recognition and machine learning, dimensionality
reduction aims to transform the high-dimensional data points in
a low-dimensional space, while retaining most of the underlying
structure in the data. It can be used to solve the curse of dimen-
sionality (Bellman, 1961), and to accomplish data visualization. Be-
sides some linear algorithms, such as principal component analysis
(PCA) (Turk and Pentland, 1991) and linear discriminant analysis
(LDA) (Belhumeur et al., 1997), manifold learning, which serves
as a nonlinear method, has attracted more and more attention
recently.
Several efficient manifold learning techniques have been pro-
posed. Isometric feature mapping (ISOMAP) (Balasubramanian
et al., 2002) estimates the geodesic distances on the manifold and
uses them for projection. Locally linear embedding (LLE) (Roweis
and Saul, 2000) projects data points to a low-dimensional space
that preserves local geometric properties. Laplacian eigenmaps
(LE) (Belkin and Niyogi, 2003) uses the weighted distance between
two points as the loss function to get the dimension reduction re-
sults. Local tangent space alignment (LTSA) (Zhang and Zha, 2004)
constructs a local tangent space for each point and obtains the glo-
bal low-dimensional embedding results through affine transforma-
tion of the local tangent spaces. Yan et al. (2007) present a general
formulation known as graph embedding to unify different dimen-
sionality reduction algorithms within a common framework.
All of the above algorithms have been widely applied. However,
serving as the batch methods, they require all training samples are
given in advance. When samples are observed sequentially, batch
method is computationally complex. This is because the batch
method needs to be run repeatedly once new samples are ob-
served. To overcome the problem, many researchers have been
working on incremental learning algorithms. The problem of incre-
mental learning can be stated as follows. Let X ¼½x
1
; x
2
; ...; x
n
be a
data set, where x
i
2 R
d
1
. Assume that the low-dimensional coordi-
nate y
i
of x
i
for the first n training samples are given. When a
new sample x
n+1
is observed, incremental learning should figure
out how to project x
n+1
in the low-dimensional space and to update
the existing samples’ low-dimensional coordinates (Liu et al.,
2006). Martin and Anil (2006) describe an incremental version of
ISOMAP: the geodesic distances are updated, and an incremental
eigen-decomposition problem is solved. Kouropteva et al. (2005)
assume the eigenvalues of the cost matrix remain the same when
a new data point arrives and the incremental learning problem of
LLE is tackled by solving a d
2
d
2
minimization problem, where
d
2
is the dimensionality of the low-dimensional embedding space.
Bengio et al. (2004) cast MDS, ISOMAP, LLE and LE in a common
framework, in which these algorithms are seen as learning eigen-
functions of a kernel, and try to generalize the dimensionality
reduction results for the novel data points. An incremental mani-
fold learning algorithm via TSA is proposed by Liu et al. (2006)
0167-8655/$ - see front matter Ó 2009 Elsevier B.V. All rights reserved.
doi:10.1016/j.patrec.2009.08.005
* Corresponding author. Fax: +86 731 84574992.
E-mail addresses: pengjia@nudt.edu.cn (P. Jia), jsyin@nudt.edu.cn (J. Yin),
dwhu@nudt.edu.cn (D. Hu).
Pattern Recognition Letters xxx (2009) xxx–xxx
Contents lists available at ScienceDirect
Pattern Recognition Letters
journal homepage: www.elsevier.com/locate/patrec
ARTICLE IN PRESS
Please cite this article in press as: Jia, P., et al. Incremental Laplacian eigenmaps by preserving adjacent information between data points. Pattern Recogni-
tion Lett. (2009), doi:10.1016/j.patrec.2009.08.005