Showing papers presented at "Virtual Environments, Human-Computer Interfaces and Measurement Systems in 2008"

An improved procedure for the automatic detection of dermoscopic structures in digital ELM images of skin lesions

Abstract: Early detection of melanoma is a very critical issue in todaypsilas dermatologic practice. Different diagnostic methods have been proposed which define multiple criteria for the evaluation of the malignancy of a lesion. The paper is devoted to the detection of an important dermatologic structure: the atypical pigmented network. A proposal is described for the application of decision-tree classification techniques to the results of specific image processing algorithms for the estimation of chromatic and structural parameters.

A microcell oriented load balancing model for collaborative virtual environments

Abstract: In this paper, we present a microcell oriented load balancing mechanism in the context of a hybrid MMOG (massively multiplayer online game) architecture. The objective of the proposed approach is to define a fair load balancing model for peer-to-peer MMOGs and virtual environments that minimizes peer-to-peer distortions in the overlays. In the case of an overloaded server, the proposed approach identifies appropriate microcell(s) that reduces overlay maintenance cost and minimizes inter-server communications. The load is relieved by devolving these microcells to the other less loaded servers. The model is justified through extensive simulation.

HugMe: A haptic videoconferencing system for interpersonal communication

Abstract: Traditional teleconferencing multimedia systems are limited to audio and video information. Human touch, in the form of handshake, encouraging pat, comforting hug, among other physical contacts, is fundamental to physical and emotional development. This paper presents the motivation and design of a synchronous haptic teleconferencing system with touch interaction to convey affection and nurture. We present a preliminary prototype for haptic poking. Examples of potential applications for HugMe include the domains of physical and/or emotional therapy, understaffed hospitals, remote children caring and distant loverspsila communication.

Human motion tracking and gait analysis: a brief review of current sensing systems and integration with intelligent environments

Abstract: Human motion tracking and gait analysis is becoming a topic of great interest in everyday applications generating a large amount of research into systems that can provide this information in real time at a low cost and with the smallest intrusion level possible. In this line different approaches have been proposed following distinct philosophies usually related to the final application of the system. This paper is aimed on one hand at providing a review of non vision based current systems highlighting how distinct and oriented towards particular applications they are. On the other this paper deals with the problem of integrating such different elements into efficient environmental intelligence applications that can be used as a base for home rehabilitation or automatic elderly assistance. This is addressed by implementing a specific device access layer within a novel distributed agent based ambient intelligence architecture called HI3.

Development of head-mounted display with eye-gaze detection function for the severely disabled

Abstract: The physically handicapped people such as the amyotrophic lateral sclerosis (ALS) patients who can move only eyes have difficulty in communicating with others. As a communication device which a user could operate by eye movement, we made a prototype of a head-mounted display (HMD) with the eye-gaze detection function. In the conventional HMD with eye-gaze detection system, the size was large and the eye-gaze calibration procedure must be repeated if the user moves relative to the HMD. To reduce the size of the HMD, first, in the developed prototype, a part of the optical path for displaying and that of the path for eye-gaze detection were used together. In addition, the HMD was used for one eye. Second, to improve the eye-gaze detection function, the eye-gaze point was determined from the relative position between the pupil center and the corneal reflection of the light source which were detected by the camera. In addition, the light source for irradiating the eye and the camera for capturing the eye image were arranged in infinite virtually. Furthermore, the display screen was set in infinite ideally. However, actually, the optical system for displaying was adjusted to myopia. As a result, the eye-gaze error due to the eye displacements relative to the finder of the HMD was yielded. So we proposed an eye-gaze compensation method to compensate the eye-gaze points. Finally, the Japanese character input experiment was conducted for three healthy students. The input speed was 3.45, 2.70, and 2.15 sec per one character, respectively.

A wearable head-mounted sensor-based apparatus for eye tracking applications

Abstract: This work presents a novel approach to eye-tracking systems using eye-glass like apparatus equipped with relatively cheap IrDA sensors and IrDA LEDs connected to a computer. The proposed system produces very low dimensional feature vectors for processing as compared to its competitors that process video data acquired from a digital camera. Consequently, the computational requirements of the proposed system are low. Furthermore, the apparatus is lightweight and can be directly worn. A prototype system is developed in our laboratories and tested to observe its capabilities. Preliminary results show that the approach provides a promising human-computer interface system with plausible accuracy.

Easy eye-gaze calibration using a moving visual target in the head-free remote eye-gaze detection system

Abstract: The development of precise head-free remote eye-gaze detection devices with easy calibration is desired for human interface and human monitoring. In the system that we developed, the 3D position of a pupil is measured using stereo wide view cameras. Next, a narrow view camera unit detecting the center of the pupil and the corneal reflection of the light source is aimed at the subject eye pupil using a pan-tilt drive. Previously, we proposed an eye-gaze detection theory in which a subject must look into the center of the aperture of a narrow view camera and at a small marker on a PC screen (two-point calibration). In our past experiments conducted with such calibration at the position of approx. 70 cm from a PC screen, the subjects shifted head positions approx. 15 cm in depth and 12 cm to lateral. The results of our experiments have already confirmed the usefulness of our two-point calibration theory and the developed system. However, unlike looking at the marker on the PC screen, it was difficult during our experiments for the subjects to look at the center of the camera at the center of the aperture because the position was unclear and it was difficult to provide the timing for the subject to look at it. In this paper, we propose a calibration method by looking at just two known points other than the camera. Furthermore, we propose a calibration method using a moving visual target on the PC screen. The experimental results show that the eye gaze precision is improved by using the moving target, rather than by using the two points on the screen or by using the previous calibration method; and, the time necessary for calibration is not different.

PupilMouse supported by head pose detection

Abstract: We have already proposed dasiaPupilMousepsila, which would be very useful for the severely handicapped people, who can move their heads, to operate a PC and so on. In PupilMouse, pupil motion between frames detected by a video camera is reflected in cursor motion on a PC screen and whether each of the right and left pupils are detected or not is reflected in the push states of the corresponding buttons of a two button mouse. Accordingly, users can move the cursor on the PC screen by head rotation, and can click by closing their single eye. If they rotate their head while closing one eye, they can drag.

Development of a stereo vision system for remotely operated robots: A control and video streaming architecture

Abstract: This paper describes the open and flexible architecture of a stereo vision system prototype, using open source software. The system is designed for teleoperated robots and includes a four degrees of freedom stereo head mechanism, a pair of high performance digital cameras, a head tracker and a head mounted display. All processes for the head control and video streaming are performed in Linux-based Real-time Operating Systems using open source libraries under GPL license. Experimental results showed that our system is capable of satisfying the hard-real time requirements for the head control, with great precision, and a low latency for the stereo video streaming. The video streaming management is particularly sophisticated resulting in a flexible, efficient and reliable service.

Instrumentation remote control through internet with PHP

Abstract: This paper describes a set of PHP based tools created to develop applications for instrumentation remote control through Web browsers. These tools include a PHP module for GPIB (general purpose interface bus) control in a Win32 platform and a set of PHP classes that make easier the creation of GUIs in Web browsers for instrument control and data visualization. The Web AJAX technology allows asynchronous data loading making it possible to have in the same browser view different panels that are able to interact and to be updated independently.

Head pose detection with one camera based on pupil and nostril detection technique

Abstract: A remote video-based head pose detection system is useful to observe the behavior of the driver, e.g., prevention oft the driver from failing to keep the eyes on the road. In addition, if the precision of the system is high, it may be used as a pointing device. We have already proposed a horizontal and vertical head pose estimation method using the 3-D positions of the two pupils and two nostrils, which are obtained from the stereo cameras. In the method, the horizontal and vertical angles of the average vector of the normal vector of the plane including the two pupils and one nostril and that of the plane including the two pupils and another nostril were determined as the head angle. The system showed the measurable ranges of more than plusmn 40 deg in horizontal and 30 deg in vertical. In this paper, we propose the head pose detection method with one camera in order to increase the horizontal range. The 3D positions of the pupils and nostrils are determined by giving the distances among the feature points as restraint conditions. The experimental results showed the measurable ranges of approx. plusmn 45 deg in horizontal and 40 deg in vertical. In addition, the one-camera method indicated high resolution compared to our previous stereo method. Finally, the proposed one-camera method was introduced into each of the two stereo-calibrated cameras, placed with 30 deg separated. The two-camera system showed a wide horizontal range of plusmn 60 deg.

An ontology based approach to intelligent data mining for environmental virtual warehouses of sensor data

Abstract: The rapid development of sensor technology led to large deployments of collections of sensing nodes working together to collect information for light, temperature, atmospheric pressure, air pollutions parameters, images, and other relevant data according to specific Environmental applications. The ability of the sensor networks to collect information accurately and reliably enables building both real-time detection and early warning systems. Environment parameter measurement and supervision received a lot of attention from both academic and industrial research communities around the world. Applications supporting decisions for rapid coordinated responses to threats such as bushfires, tsunamis, earthquakes, and other crisis situation have been devised. In this paper a combined ontology and rule-bases intelligent system build over a platform for sensor data warehousing for decision support is introduced. A combined ontology of sensor networks and sensor data for environment parameter measurement is designed and discussed. A set of rule-based systems each tailored to a domain of networked sensors are linked together through a middle-layer of rule-base systems which reason with facts classified and structured as instances of the common sensor ontology. A set of meta-rules direct the intelligent activity of the whole system and requires individual rule-based systems to reason upon specific facts. The paper will also discuss the architecture and algorithms for data mining, fusion and reasoning for specific situation in Environment monitoring and supervision. Results obtained from experiments performed on the system prototype are given at the end of this paper.

LOADER: A Location-Aware Distributed Virtual Environment Architecture

Abstract: This article proposes a new architecture for distributed data management and update massage exchange in massively multi-user virtual environments. The key points in the design of such environments are scalability and QoS-aware message delivery. Therefore it requires robust distributed algorithms in a dynamic peer-to-peer system with frequent node arrivals and departures. Our proposed approach is mainly based on distributed hash tables (DHTs) in order to achieve a decentralized system where any participating node can efficiently retrieve the updates associated with a given object. Therefore, the responsibility of maintaining the mapping from names to values is distributed among the nodes in a way that a change in the set of participants causes a minimal amount of disruption. This allows the design to scale to extremely large number of nodes and to handle continual node arrivals, departures, and failures. The original form of DHT has several deficiencies for multi-user virtual environment application. This work introduces LOADER: a Location Aware Distributed Virtual Environment Architecture, which is the result of a series of efforts in alleviating a number of these problems including lack of location-aware ID assignment. Moreover, efficient multicast is addressed as an inevitable requirement for message exchange in multi-user environments and a solution based on Scribe is proposed.

Virtual Data Warehouse architecture for real-time WebGIS

Abstract: Environmental monitoring requires that raw data acquired from sensors and/or data repositories be transformed, by scientific analysis, into assessments of current ecosystem conditions and in evolution trends in time and space. The huge data amount produced by different sources, the complexity of the environmental models adopted and the necessary distributed collaboration between scientists and government agencies, require specific applications to process and understand environmental phenomena and validate results. GIS domain received a great deal of attention from the scientific and industrial applications communities. Many algorithms, protocols, and applications have been built through the ears for the collection, investigation, analysis, and synthesis of data obtained from sensors ranging from temperature, pressure, etc. to satellite imaging. Almost all attempts have been made to deal with data obtained from lumped repositories. Little or almost none works are reported about a general and flexible mechanism used to display geo-dependent data as it is generated. In this paper we present a GIS platform whose goal is to efficiently mine, fuse, and exploit environmental data and to synthetically display the results at the pace the data is produces. A virtual data warehouse to use GIS information is proposed to manage and collect data acquired by and from several sources. The proposed platform allows users to access to environmental data collected by different sources, to register, normalize and visualize data for exploring and analyzing complex structure and relationship, to process data using distributed computing resources and web applications. To evaluate the effectiveness of the proposed prototype, we present a case study related to data fusion of Modis files and Geo-Located real sensor data for air quality monitoring.

Voltage notch detection and analysis using wavelets

Abstract: This paper presents a low-cost virtual instrument for detection and analysis of voltage notches in voltage supply using wavelets. A simple wavelet decomposition tree has been used for detection and analysis of the two main features of voltage notching: the transients associated with the beginning and the end of the commutation notches and the stationary high-frequency components of the spectrum of the signal. The results obtained show the performance of the method proposed in the detection and analysis of the time-frequency characteristics of voltage notching.

A distributed interest management scheme for massively multi-user virtual environments

Abstract: Massively multi user virtual environment (MMVE) applications must deal with the challenge of update message exchange among a large set of nodes distributed over the Internet. Therefore design of scalable network protocols is a major concern in such large scale distributed architectures. Several approaches have been proposed to aid update exchange in MMVEs. Message localization has always been a key point in the design of such distributed network protocols. Area of interest management (AoIM) mainly deals with the issues related to the update message localization with respect to the userpsilas interest. As the number of users in the virtual environment increases, update message localization becomes more important in order to prevent the transmission of a huge bulk of unnecessary updates to uninterested users. Therefore, scalable and efficient area of interest management is a crucial point in MMVE design. This paper introduces a new zone selection and distributed regional message filtering architecture for MMVE applications. We propose Delaunay tetrahedrization as a good way of virtual world partitioning due to several promising features. Moreover we propose the partitioning to be done with respect to barriers in order to reach a better performance through the filtering the updates that need not be propagated over the barriers. We will also introduce a distributed interest management protocol based on the previous partitioning technique. Our proposed distributed message dissemination approach is capable of providing the interested users with variable updates rate according to their required level of detail.

A novel approach to video matting using automated scribbling by motion analysis

Abstract: Video matting can be described as a method of extracting the foreground object from each frame of a video and composite (or transfer) it to a different background or a different video. An automatic scribbling approach based on the motion of the foreground object in a video is introduced. Probability maps (PMs) are computed by analysing the motion of object in the video. In the proposed technique the corrupted PMs are refined and reconstructed using morphological techniques. The frames are scribbled with reference to the reconstructed PMs. Closed form solution based matting technique uses the scribbled frame to yield the matte and the foreground.

Experimental characterization of synchronization protocols for wireless networks

Abstract: Nowadays more and more measurement applications where sensor nodes cooperate to realize a data fusion process are entrusted to wireless sensor networks (WSN). Data fusion to be accurate requires that nodes be referred to a common clock and among themselves. In this scenario node synchronization got a crucial research topic and even sophisticated synchronization algorithms can be easily found in literature. Not a few others show to be especially designed for low cost, low memory and low power architectures. Their performance is usually evaluated either through analytical considerations or in simulation environments, but in some cases where ad hoc radio systems have been adopted. This paper makes a first step toward an experimental characterization of synchronization protocols that hold into account also influence factors which arise when commercial wireless communication busses as WiFi, BlueTooth (BT), ZigBee are adopted.

New DAQB and associated virtual library included in LabVIEW for environmental parameters monitoring

Abstract: In this work a data acquisition board (DAQB) with data transfer by serial port and the associated virtual library included into LabVIEW software are presented. The DAQB developed around a National Semiconductor LM 12458 devices, have the capability to perform tasks that diminish the host processor work and is capable to communicate with the host computer by using a set of drivers associated. Highly integrated device circuit that has into it the most components of the board, facility in data handling, good metrological performance and a very low cost are the benefits of the proposed system. Using the LabView environment, we have realized a virtual instrument able to get from the prototype data acquisition board for environmental monitoring parameters the information about air pollution factors like CO, H2S, SO2, NO, NO2 etc. In order to get effective information about those factors and the monitoring points, this intelligent measurement system, compound from portable computer, and Gas detector. This system can be used to map the information about the air pollution factors dispersion in order to answer to the needs of residential and industrial areas expansion.

Simulative study of target tracking accuracy based on time synchronization error in wireless sensor networks

Abstract: Target tracking is one of the popular applications of wireless sensor networks (WSN). Randomly distributed sensor nodes(motes) in environment gather spatio-temporal information about target(s) and send them to a sink node for further processing. Motes like personal computers use low cost crystal based clocks. In order to maintain synchronization accuracy to acceptable levels, we shall need to synchronize them quite often. Time synchronization tries to control the time accuracy in WSN but it still has a specific limited accuracy. Motes partly process their sensed data using local fusion before sending them to the sink. Target tracking has two major error sources, first of all is that the equation system most of times gives two different answers which target can be placed in one of them. Second factor is that low time accuracy causes the great amounts of errors in results. Choosing proper fusion methods and sensing coverage degree helps us to increase the accuracy of target tracking results.

Virtual environment for granulometry analysis

Abstract: The analysis of granulometry of substances is relevant in a great variety of the research and industrial applications. Unfortunately, image-based algorithms for granulometry analysis are difficult to tune and validate. In a typical setup, one or more cameras acquire images of a scene with a great number of objects or particles that must be measured. The distribution of the sizes/shape characteristics of the elements are the common output of such systems. The creation of supervised image database where the coordinates of all elements are known is very important and it allows for testing in a suitable manner the final size/shape distribution of particles produced by the image processing system with respect to the real distribution. Due to the great amount of objects or particles in the images, it is not often convenient, or even impossible, to individually measure each single objects in order to test the capability of the image processing system to locate and measure the elements (creation of a supervised dataset). One possible solution encompasses the creation of a synthetic image dataset where the position of each elements is known a priori. In this paper we propose a virtual environment to create and test an image-based granulometric system based on the 3D engine Blender. Results are encouraging and show the effectiveness of the proposed method.

Using a rendering engine to support the development of immersive virtual reality applications

Abstract: This work presents the features of a exible realtime 3D graphics engine aimed at the development of multimedia applications and collaborative virtual environments. The engine, called EnCIMA (engine for collaborative and immersive multimedia applications), enables a quick development process of applications by providing a high level interface, which has been implemented using the C++ object-oriented programming paradigm. Important characteristics of the engine are the integration of several real time graphics techniques needed by visualization applications; access to network connection management to support collaboration; 3D sound capability; the support to various specialized interaction equipments such as 3D mice, haptic devices, 3D motion trackers, data-gloves, joypads, force feedback joysticks, and; the capacity to have rendering computation and Physics simulation assigned to GPUs and PPUs, respectively. The engine also enables the developer to choose how the scene should be rendered to, i.e. using standard display devices, stereoscopy, or even several simultaneous projection for spatially immersive displays. As part of the evaluation process, we have compared the performance of EnCIMA to a game engine and two scene graph toolkits, through the use of a testbed application.

Modeling of flexible needle for haptic insertion simulation

Abstract: Needle buckling is commonly observed in the surgical procedure of flexible needle insertion. Unexpected buckling can seriously affect the insertion performances, and it should be avoided because it causes unstable and undesirable motion of the needle, thereby damages surrounding vital tissue structures. Although needle insertion simulation methods using haptic interfaces have been reported, yet no extensive study of needle buckle modeling and its haptic simulation can be found. Therefore, in this paper modeling methods of needle buckling in air, buckling in homogeneous tissue, and buckling in multi-layered tissues are proposed. An energy-based method is used to model the feedback force in the insertion procedure through a haptic interface. An experimental simulation system based on a haptic interface is developed.

Supporting web-based e-learning through collaborative virtual environments for radiotherapy treatment: A formal design

Abstract: Web based virtual reality application has been widely used in education, virtual conferences, entertainment. Observing the progress of the gaming industry over the years can clearly show the advancement in virtual reality Web application and virtual environments. In this paper, we propose a novel Web based e-learning application design approach that uses discrete event system specification (DEVS) formalism to form and model the 3D virtual hospital Web based application for radiotherapy and cancer care treatment class of applications. We present a case study that demonstrates the value of this formal approach in modeling and designing 3D virtual environment and Web based e-learning class of application.

KissMe: Bringing virtual events to the real world

Abstract: Several researchers have successfully developed realistic models for real world objects/phenomenon and have simulated them in the virtual world. In this paper, we propose the opposite: brining virtual world events and instantiate them in the real world. The proposed system, named KissMe, comprises two components: (1) a virtual reality environment that has avatars that represent real humans interacting with each other, and (2) a neck piece (tactile haptic device) that is put on the neck of the real person. When one of the avatars kisses the other, an event is triggered and a message is sent over the Internet, via web service paradigm, to a Bluetooth-enabled neck piece hardware. The neck piece applies the haptic stimulus that simulates the kiss feeling using actuators that are embedded in a scarf-like suit. Examples of potential applications for the KissMe prototype include 3D gaming and virtual reality social communities such as second life, among others.

Indirect group interaction in interpeceptives virtual environments

Abstract: This paper proposes a component that can capture a variety of user movements and use that to create information and interaction with computational applications, like electronic games and Interactive Digital TV Programs in a pervasive approach. Some techniques and systems get information from the user, like thoughts and actions, to provide extra functionality but that is done for one user at each time. The component proposed here bases itself on observing the user, thus it is able to detect his thoughts and feelings based on his actions, providing ways for users to interact seamlessly and for the system to change its outputs and states based on whatever the users are doing. Besides that, systems might be created to support multiple inputs from groups of users providing a whole new range of outputs. The events generated through these users observation are referred here as Indirect Group Interaction.

An implementation of web based PDM with open source CMS

Abstract: The importance of content management systems (CMS) has increased dramatically in recent years, but the open source CMS is usually criticized for the lack of applications in manufacturing fields. CMS has predominantly focused on managing documents, and on the other hand, product data management (PDM) is a digital repository of product information, including non-paper representations like CAD files. In this paper, a Web based PDM System is implemented and integrated with the open source CMS to cope with the tasks of the mechanical design. There are three major functions provided in this system. First of all, to provide users with a Web based product data vault system for design related files storage. Secondly, a data-sharing and collaboration system are created to enhance the pre-manufacturing planning and detailed design communication. The third function of this system allows user to setup an efficient programming environment for the engineering analysis processes.

Design and implementation of an integrated man-machine interface by touch panel for an embedded electronic measurement system

Abstract: In this paper we design and implement an integrated man-machine touch panel interface for an embedded electronic measurement system (EEMS). The interface module of our EEMS includes general electronic measurement instruments such as a waveform generator, an oscilloscope and a power supply. We integrate three man-machine interfaces into one window which works in cooperation with the touch panel. The display function and the input function are controlled by different registers in the touch panel. We also design a corresponding display interface and a corresponding input interface. For the waveform generator we provide a basic waveform output button and include sine, triangle, square and arbitrary waveforms. The arbitrary waveform allows the user to draw on the grid area of the panel by hand. The output voltage and the frequency are adjustable. The oscilloscope has a grid area to show the waveform and the frequency. The power supply has an adjustable estimate to adjust the output voltage. The external interface circuit includes a waveform generator, an oscilloscope and a power supply. The embedded system connects to the external interface circuit through the general purpose input/output port (GPIO). The power supply and the waveform generator provide an output function which outputs the digital data from the embedded system. The digital data are converted by the Digital Analog Converter (DAC) and then the analog signal is output. The oscilloscope has an input function. After the external analog signal has been converted by the Analog Digital Converter (ADC), the digital data are analyzed by the embedded system and displayed in the touch panel.

Scrutinizing pseudo haptic feedback of surface roughness in virtual environments

Abstract: Operators in virtual environments have to mostly rely on visual feedback when exploring virtual scenes and objects. If no additional haptic actuators are available then information about surface roughness will not be communicable and thus the degree of immersion will suffer. To compensate for this shortcome the usage of pseudo haptic feedback (Control/ Display ratio = visual cues encoding haptic object properties) is discussed and two psychophysical experiments are conducted. The first experiment deals with the perceptual scaling of different Control/ Display ratios while the second experiment examines the way, how human subjects assign suitable Control/ Display ratios to different real surfaces. It turns out that human operators can reliably perceive differences in Control/ Display ratios and a psychophysic function is established. The allocation of specific Control/ Display values to real materials does not give any generalizable results; only a global trend is observable.

Web applications as health provision tool

Abstract: Web interfaces to automated, device-driven health monitoring systems are necessary to narrow and to bridge the quality gap between physiological observation and semiological interpretation. When designed according to metrology principles, such interfaces are useful in overcoming the measurement and data quality problems created by the lack of safety science in health care and the associated cost of cognition, capability, communication, and coordination.