Nikolaos G. Bourbakis

A Survey on Wearable Sensor-Based Systems for Health Monitoring and Prognosis

The design and development of wearable biosensor systems for health monitoring has garnered lots of attention in the scientific community and the industry during the last years. Mainly motivated by increasing healthcare costs and propelled by recent technological advances in miniature biosensing devices, smart textiles, microelectronics, and wireless communications, the continuous advance of wearable sensor-based systems will potentially transform the future of healthcare by enabling proactive personal health management and ubiquitous monitoring of a patients health condition. These systems can comprise various types of small physiological sensors, transmission modules and processing capabilities, and can thus facilitate low-cost wearable unobtrusive solutions for continuous all-day and any-place health, mental and activity status monitoring. This paper attempts to comprehensively review the current research and development on wearable biosensor systems for health monitoring. A variety of system implementations are compared in an approach to identify the technological shortcomings of the current state-of-the-art in wearable biosensor solutions. An emphasis is given to multiparameter physiological sensing system designs, providing reliable vital signs measurements and incorporating real-time decision support for early detection of symptoms or context awareness. In order to evaluate the maturity level of the top current achievements in wearable health-monitoring systems, a set of significant features, that best describe the functionality and the characteristics of the systems, has been selected to derive a thorough study. The aim of this survey is not to criticize, but to serve as a reference for researchers and developers in this scientific area and to provide direction for future research improvements.

A survey of skin-color modeling and detection methods

Skin detection plays an important role in a wide range of image processing applications ranging from face detection, face tracking, gesture analysis, content-based image retrieval systems and to various human computer interaction domains. Recently, skin detection methodologies based on skin-color information as a cue has gained much attention as skin-color provides computationally effective yet, robust information against rotations, scaling and partial occlusions. Skin detection using color information can be a challenging task as the skin appearance in images is affected by various factors such as illumination, background, camera characteristics, and ethnicity. Numerous techniques are presented in literature for skin detection using color. In this paper, we provide a critical up-to-date review of the various skin modeling and classification strategies based on color information in the visual spectrum. The review is divided into three different categories: first, we present the various color spaces used for skin modeling and detection. Second, we present different skin modeling and classification approaches. However, many of these works are limited in performance due to real-world conditions such as illumination and viewing conditions. To cope up with the rapidly changing illumination conditions, illumination adaptation techniques are applied along with skin-color detection. Third, we present various approaches that use skin-color constancy and dynamic adaptation techniques to improve the skin detection performance in dynamically changing illumination and environmental conditions. Wherever available, we also indicate the various factors under which the skin detection techniques perform well.

Wearable Obstacle Avoidance Electronic Travel Aids for Blind: A Survey

The last decades a variety of portable or wearable navigation systems have been developed to assist visually impaired people during navigation in known or unknown, indoor or outdoor environments. There are three main categories of these systems: electronic travel aids (ETAs), electronic orientation aids (EOAs), and position locator devices (PLDs). This paper presents a comparative survey among portable/wearable obstacle detection/avoidance systems (a subcategory of ETAs) in an effort to inform the research community and users about the capabilities of these systems and about the progress in assistive technology for visually impaired people. The survey is based on various features and performance parameters of the systems that classify them in categories, giving qualitative-quantitative measures. Finally, it offers a ranking, which will serve only as a reference point and not as a critique on these systems.

Picture data encryption using scan patterns

Abstract An efficient scheme for two-dimensional (2D) data encryption is presented. This scheme is based on the principles and ideas reflected by the specification and development of the SCAN language, and is mainly motivated for the encryption of 2D digital pictures. The wide range of sequential accessing patterns that are produced by the SCAN grammar, allows the consideration of a SCAN word as an encryption key bound to a given 2D image array. The application of this word on the initial array data produces the rearrangement to them into an encrypted final sequential representation, which is dictated by the accessing pattern that it represents. The creation of each SCAN pattern is combined by the insertion of “additive noises” at particular image points. The encryption algorithm is derived from the implementation algorithm of the SCAN language and is presented here. Decryption can be performed by an inverse procedure, whose implementing algorithm is also given. Finally, some experimental results are presented illustrating a set of enciphered representations of a real picture.

Image and video encryption using SCAN patterns

Abstract This paper presents a new method for image and video encryption and a first stage lossy video compression based on frames difference before the encryption. The encryption methods are based on the SCAN methodology which is a formal language-based two-dimensional spatial accessing methodology which can generate very large number of scanning paths or space filling curves. The image encryption is performed by SCAN-based permutation of pixels and a substitution rule which together form an iterated product cipher. The video encryption is performed by first lossy compressing adjacent frame differences and then encrypting the compressed frame differences. The main characteristics of the proposed methods are image encryption, first stage compression-based frames differences and encryption of video whose compression error can be bounded pixelwise by a user specified value, very large number of encryption keys, and ability to encrypt large blocks of any digital data. Results from the use of the methods proposed here are also provided.

A fuzzy region growing approach for segmentation of color images

Segmentation is one of the most important preprocessing steps towards pattern recognition and image understanding and a significant step towards image compression and coding. With detecting edges, most of the large segments can be found and separated from others by edge pixels. It is, however, the pixels on edge locations or those in high detailed areas whose association to adjacent segments must be found. A pixel can be a part of the closest segment or in association with the neighboring pixels from a new smaller segment. In this paper, two segmentation algorithms are presented. One is used for fine segmentation towards compression and coding of images and the other for coarse segmentation towards other applications like object recognition and image understanding. Edge detection and region growing approaches are combined to find large and crisp segments for coarse segmentation. Segments can grow or expand based on two fuzzy criteria. The fuzzy region growing and expanding approaches presented here use histogram tables for fine segmentation. The procedures introduced here can be used in any order or combination to yield the best result for any particular application or image type.

A survey on wearable biosensor systems for health monitoring

Wearable biosensor systems for health monitoring are an emerging trend and are expected to enable proactive personal health management and better treatment of various medical conditions. These systems, comprising various types of small physiological sensors, transmission modules and processing capabilities, promise to change the future of health care, by providing low-cost wearable unobtrusive solutions for continuous all-day and any-place health, mental and activity status monitoring. This paper presents a comprehensive survey on the research and development done so far on wearable biosensor systems for health-monitoring, by comparing a variety of current system implementations and approaches and identifying their technological shortcomings. A set of significant features, that best describe the functionality and the characteristics of wearable biosensor systems, has been selected to derive a thorough study. The aim of this survey is not to criticize, but to serve as a reference for current achievements and their maturity level and to provide direction for future research improvements.

Data-image-video encryption

This paper describes the most representative algorithms and standards for the encryption of data, digital images and MPEG video. The general model a typical encryption/decryption system about the security principle is discussed. Data encryption mainly is the scrambling of the content of data, text, image, audio, and video and to make the data unreadable, invisible or incomprehensible during ciphertext transmission. The goal is to protect the content of the data against the attackers. The reverse of data encryption is data decryption, which recovers the original data. There are two types of encryption/decryption key: the public-key system and the private-key system. The most promising features are joint lossless compression, joint encryption and hiding based on SCAN language which analyses the unique properties of digital image and video and search for high security algorithms to reduce the overall computational cost.

Detection of Small Bowel Polyps and Ulcers in Wireless Capsule Endoscopy Videos

Over the last decade, wireless capsule endoscopy (WCE) technology has become a very useful tool for diagnosing diseases within the human digestive tract. Physicians using WCE can examine the digestive tract in a minimally invasive way searching for pathological abnormalities such as bleeding, polyps, ulcers, and Crohns disease. To improve effectiveness of WCE, researchers have developed software methods to automatically detect these diseases at a high rate of success. This paper proposes a novel synergistic methodology for automatically discovering polyps (protrusions) and perforated ulcers in WCE video frames. Finally, results of the methodology are given and statistical comparisons are also presented relevant to other works.

Sensing Surrounding 3-D Space for Navigation of the Blind

This article presents a two-dimensional (2-D) vibration array for detecting dynamic changes in three-dimensional (3-D) space during navigation and provides these changes in real time to visually impaired users (in a form of vibration) to develop a 3-D sensing of the space and assist their navigation in their working and living environment. This vibration array is a part of the Tyflos prototype device (consisting of two tiny cameras, a microphone, an ear speaker mounted into a pair of dark glasses and connected into a portable PC) for blind individuals. The overall idea is of detecting changes in a 3-D space is based on fusing range data and image data captured by the cameras and creating the 3-D representation of the surrounding space. This 3-D representation of the space and its changes are mapped onto a 2-D vibration array placed on the chest of the blind user. The degree of vibration offers a sensing of the 3-D space and its changes to the user. It is concluded that the power conception will be associated with the potential of the batteries of the portable computer (notebook). Thus, the visually impaired user has to recharge the batteries after a certain time or carry additional batteries connected to notebook.