Appl. Math. Inf. Sci. 9, No. 3, 1587-1592 (2015) 1587
Applied Mathematics & Information Sciences
An International Journal
http://dx.doi.org/10.12785/amis/090355
Information Hiding for Medical Privacy Protection based
on GHM and Canny Edge Detection
Ren Shuai
1,∗
, Zhao Xiangmo
1
and Zhang Tao
2
1
School of Information Engineering, Chang’an University, Xi’an 710064, China
2
School of Electronic and Control Engineering, Chang’an University, Xi’an 710064, China
Received: 25 Aug. 2014, Revised: 25 Nov. 2014, Accepted: 26 Nov. 2014
Published online: 1 May 2015
Abstract: In order to protect the personal and diagnosis information of patient, GHM and Canny edge detection are employed in this
algorithm to process the original CT digital image. The original image will be firstly processed GHM for a global analysis. According
to different importance degrees, CT images can be distributed into LL
2
, LH
2
, HL
2
and HH
2
by GHM multi-wavelet. After that, the
distributed sub-images will be processed by Canny edge detection. For example, the edges of LL
2
(with the highest important degree)
and HH
2
(with the lowest important degree) are detected by strong Canny method. Then many thin edges can be obtained, which are
useless for medical diagnosis, privacy and diagnosis information can be hid by deletion and comparison processing of invalid edges.
The experimental results indicate that the robustness and capacity of watermarked CT images can be improved after this algorithm.
Keywords: Diagnosis Gray or Binary Image, Privacy Protection, GHM Multi-Wavelet, Canny Edge Detection.
1 Introduction
Nowadays, personal privacy security has become one of
the issues concerned most in digital era. Long after
sectors like banking and finance, recently more and more
digital auxiliary diagnostic equipment are brought into
daily practical operation in medicine field. Individual
medical records, carrying ever more sensitive personal
information, are already being gathered and stored by the
tens of thousands in databanks maintained by hospital
networks, health maintenance organizations, and drug
companies [
1]. As a result, information storage methods
of the patients have changed from papery-based into
electronic-based.
There are several common image formats in medical
field, such as CT, MRI, X-ray, and so on. Some of those
electronic-based images are in analog formats and others
are in digital formats. Because of the convenience of the
digital images, the old analog images are converted into
digital ones. One of the problems brought by the popular
of digital medical images is the privacy information
security, which will make the relationship between both
sides of the health care worse. And reasonable method
can solve the problem. It is well known that digital
products can easily be illegally edited, modified, copied
and disseminated. These properties bring great
convenience, but at the same time it will inevitably
produce the issue of privacy disclosure of patients
information. Considering about the medical
characteristics, some scholars use the professional
mathematical model to analyze the natural system images
of human body [
2]. This model can simplify the
representation of some special medical images, like MRI
brain image, so it can find some redundancy to be the
storage space. Refer to it, getting the redundancy of
medical images will be the first concern of our algorithm,
but the algorithm proposed in our research can be used to
handle many kinds of medical images, rather than limited
to MRI images. Many other scholars achieve the goals of
medical privacy protection and authentication by using
watermarking [
3]. Most of these schemes embed robust
watermark into the digital medical images based on
frequency-domain methods, such as DCT, DWT, DFT,
and so on. And almost all of them select the appropriate
coefficients for watermark embedding [
4].
Most of the digital medical images are gray scale
images, and some of them are the binary images. Based
on our previous studies, we know very well about the
properties of gray scale and binary images [
5]. From [6]
we find that GHM multi-wavelet transform has much
∗
Corresponding author e-mail:
maxwellren@qq.com
c
2015 NSP
Natural Sciences Publishing Cor.