Image Mosaic Based on SIFT and Morphological
Component Analysis
Shuai Chen
1
, Yixiang Lu
1, ∗
, Qingwei Gao
1
1
School of Electrical Engineering and Automation,
Anhui University, Hefei 230601, China
Dong Sun
1
, Yi Xia
1
, Xueming Peng
1,2
2
Shanghai Huawei Technology
Co., Ltd, Shanghai 200120, China
Abstract—Due to traditional image mosaicing resulting in
remarkable seams, we propose a novel method to address
the problem to make the result more smooth. The approach
is constructed based on SIFT algorithm and morphological
component analysis(MCA) over trained dictionaries. The two
cores of image mosaic are image registration and fusion. First,
feature points are extracted by the SIFT algorithm which are
used to realize image registration. Then we employ K-SVD
algorithm to train an overcomplete dictionary based on the
original images and use the MCA to decompose the images so
that the decomposed components cartoon, texture can be used to
fuse images, respectively. This method leads to a state-of-the-art
mosaic performance, meanwhile, the noise contained by original
images can also be filtered.
Index Terms—SIFT; image registration; trained dictionary; K-
SVD; MCA.
I. INTRODUCTION
Image mosaicing is one of the most important research
fields in image processing. Especially with the development
of computer vision and computer graphics, image stitching
technology is more and more mature and widely used in
various fields. Image mosaicing can be regarded as a process of
joining some images to construct a complete wide view image.
Image registration [1] and image fusion [2]are two main steps
in image mosaic process.
Image registration refers to determing the overlapping areas
of the image to be spliced, and then compute transformation
relationship. According to literatures, there are three meth-
ods are widely used in image registration: gray informa-
tion based(e.g., correlation methods [3]), transform domain
based(e.g., Fast Fourier transform based methods [4]), and
feature based methods(e.g, edges and corners etc). Among
them, the feature-based image stitching technology is popular
in image registration, because it can achieve higher matching
accuracy, time efficiency and robustness. Image fusion aims at
stitching the same scene of the two images taken at different
times, from different viewpoints, or different sensors in order
to form a smooth and seamless image. Image fusion can
be performed at pixel-level, feature-level, feature-level and
decision-level [5] [6]. At present, pixel-level fusion takes up a
large proportion in the fusion algorithms. Besides, pixel-level
fusion can also be implemented in spatial domain(e.g., weight-
ed averaged method, principal component analysis method
[7]) and transformation domain(e.g., discrete wavelet trans-
form(DWT) [8] [9] [10] and curvelet transform(CVT) [11]
[12]). However, these methods mentioned above consider the
whole image as a single component. And the information
of images can not be represented completely. So we took
the morphological component analysis [13] to decompose an
image into two components which made the presentation of
the image more complete and effective.
In this paper, we proposed a new method to mosaic im-
age which fuses the different components of the overlaps
independently in the sparse land. Compared with traditional
mosaicing methods, the knowledge of sparse representation
is introduced into image fusion, which can produce a more
smooth image effectively. Meanwhile, the noise contained
in the original images will be filtered during the process
of dictionary training and image decomposition. The basic
process can be summarized as follows: first, the SIFT [14]
algorithm is used to extract keypoints from the two images A
and B which capture different portions of the same scene with
an overlapped region. In fact, we use lightness to replace gray
level. According to the morphological component analysis, the
RGB color space is converted to HSV color space, which is
more suitable for color image processing. In fact, there also
exits an residual image for the noiseless image. Finally, the
cartoon, texture and residual images are fused respectively to
form new images(fused cartoon, texture and residual image),
and then construct a complete image by using the three images.
The fused image should be reconverted to RGB image. Fig.
1 shows the image stitching flow based on point feature. In
summary, image mosaic consists of feature points extraction,
feature points matching, computing the transformation rela-
tionship and image fusion [15].
The rest of this paper is organized as follows: Section 2
gives a detailed description of the proposed method, Section
3 shows the experimental results of our novel methods, and a
conclusion is drawn in Section 4.
II. MATERIALS AND METHODS
A. Feature points extraction
The first step in the image mosaic algorithm is to extract and
match features between two images. In practical application,
there exists many methods of feature extraction, such as Harris
corner detection [16], MSER (Maximally Stable Extremal
Region) [17] and the SIFT algorithm etc. In most cases, due to
there are variations of translation and rotation points between
two images in overlapping regions, therefore, in order to
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