The company where this thesis was formulated constructs VR applications for the medical environment. The hardware used is ordinary dektops with consumer level graphics cards and haptic devices. In medicin some operations require microscopes or cameras. In order to simulate these in a virtual reality environment for educational purposes, the effect of depth of field or focus have to be considered. A working algorithm that generates this optical occurence in realtime, stereo rendered computer graphics is presented in this thesis. The algorithm is implemented in OpenGL and C++ to later be combined with a VR application simulating eye-surgery which is built with OpenGL Optimizer. Several different approaches are described in this report. The call for realtime stereo rendering (~60 fps) means taking advantage of the graphics hardware to a great extent. In OpenGL this means using the extensions to a specific graphic chip for better performance, in this case the algorithm is implemented for a GeForce3 card. To increase the speed of the algorithm much of the workload is moved from the CPU to the GPU (Graphics Processing Unit). By re-defining parts of the ordinary OpenGL pipeline via vertex programs, a distance-from-focus map can be stored in the alpha channel of the final image with little time loss. This can effectively be used to blend a previously blurred version of the scene with a normal render. Different techniques to quickly blur a renderedimage is discussed, to keep the speed up solutions that require moving data from the graphics card is not an option.

Denna rapport är en beskrivning av ett examensarbete utfört vid SPM Instrument AB i Strängnäs. SPM Instrument utvecklar och tillverkar produkter för konditionsmätning av maskiner. Målet var att skapa en cd-presentation i redigeringsprogrammet Macromedia Flash 5.0, som på ett enkelt sätt med rörliga bilder förklarar en konditionsmätningsmetod som kallas för Stöt Puls Metoden. Uppgiften löstes genom att först inhämta information om Stöt Puls Metoden, sedan utformades Flash-filmen och slutligen testades och utvecklades filmen tills dess att jag och SPM Instrument var nöjda. / This report describes a final-year project performed at SPM Instrument AB in Strängnäs. The company develop and manufacture products for condition monitoring of machinery equipment. The goal was to create a cd-presentation in the computer software Macromedia Flash 5.0, with moving pictures which explains a condition monitoring method that is called the Shoke Pulse Method. The task was solved by first finding out information about the Shoke Pulse Method, then the Flash-movie was created and finally the movie was tested and developed until both I and SPM Instrument was satisfied.

The idea for the thesis “Construction and implementation of a mobile prototype; The Lovebomb” originates from doctoral candidates Rebecca Hansson and Tobias Skog from PLAY Research Group at the Interactive Institute in Gothenburg. The object of the master thesis is to construct two working LoveBomb prototypes, one mother console belonging to the LoveBomb and blueprints for both. The LoveBomb (the picture to the right shows a possible design) is intended to encourage people to express themselves emotionally when situated amongst strangers in public spaces. Two buttons control the device, which contains a radio transceiver. By pushing the buttons the user can either send a happy message or a sad message. The LoveBombs in the vicinity receive the sent message and lets its user know which message that has been received by vibrating either a sad irregular pulse or a happy continuous pulse. While vibrating the LoveBomb send out a confirm message. The confirm message can only be received by a LoveBomb which has recently sent out a message. After receiving a confirm message the LoveBomb conveys this to the user by turning on a red LED (light emitting diode) and letting the LED shine for about half a minute. During this time the LoveBomb can only receive messages. If it receives a message, during these 30 seconds, the LED is turned off and the prototype starts vibrating according to the received message. Should a LoveBomb which has sent a message fail to receive a confirm message it conveys this to the user by turning on and off the LED three times. After this the prototype is ready to send another message. The picture below shows a state diagram of the LoveBomb. The mother console registers all the communication between the LoveBomb, by pushing a button the user can see how many happy respectively sad messages that has been sent. Our workstarted with the doctoral candidates communicating their thoughts and wishes concerning the prototype to us. We organized this information into a requirement specification. We started the development of the Lovebomb and the belonging mother console by selecting a suitable micro controller. We choose PIC16C84 from Microchip but changed later to its successor PIC16F84, because the latter was easier to get a hold of. The micro controller controls all the other components. When we knew how to program the micro controller, we started working with a transceiver, suggested by the doctoral candidates, DR3001 from RFM. After establishing a meaningful communication between two micro controllers connected with on transceiver each, this was the hardest and most important part, we began working with not so vital component such as diodes, vibrators and buttons. When we were finished with the implementation and construction we examined the prototype and compared it to the requirement specification. To our satisfaction the prototype did not differ a lot from the requirements and the existing differences were improvements from the original idea. During the development process both of us learned a lot about assembler programming, electrical engineering and radio communication.

TV and radio services have always been distributed over analogue broadcasting networks and been received on a TV -set or a radio receiver. Today this situation is changing due to digitalization and convergence between broadcasting, telecommunications and data communications. Other terminals, such as a PC, can also receive TV and radio services. Digital TV and radio can offer additional services such as e-commerce, electronic program guides and content synchronized to the TV and radio shows. If these services are to be received by several receiving terminals with different properties, the services must be adapted to the terminals. This can be done by scaling the services, meaning that the appearances and functionality of the services vary depending on the terminals’ properties. In this thesis scalable services are examined from a terminal point of view. Present and future receivers, platforms and possible methods to achieve scalability are presented, and their effects on scalable services are discussed. / TV- och radiosändningar har fram till nyligen endast distribuerats över analoga TV- och radionät och tagits emot av traditionella TV- och radioapparater, men detta håller på att ändras i och med att sändningarna digitaliseras och konvergens sker mellan broadcasting, telekom och datakom. Nu kan även andra terminaler fungera som mottagare, t.ex. en PC med ett digital-TVkort eller ett digital-radiokort. Digital TV och radio erbjuder tilläggstjänster som t.ex. ehandel, tjänster kopplade till radio- eller TV-program och elektroniska programguider. Om samma tjänst ska kunna tas emot på flera olika mottagarterminaler med olika egenskaper, måste tjänsten anpassas efter terminalerna. Detta kan göras genom att skala tjänsten, dvs. utseendet och funktionerna varierar beroende på bl.a. terminalens kapacitet. I detta arbete har terminalaspekterna på skalbara tjänster undersökts. Aktuella och framtida terminaler, plattformar och eventuella skalbarhetslösningar presenteras, och deras påverkan på skalbara tjänster diskuteras.

To efficiently examine volumetric data sets from CT or MRI scans good volume rendering applications are needed. This thesis describes the design and implementation of an application programming interface (API) to be used when developing volume-rendering applications. A complete application programming interface has been designed. The interface is designed so that it makes writing application programs containing volume rendering fast and easy. The interface also makes created application programs hardware independent. Volume rendering using 3d-textures is implemented on Windows and Unix platforms. Rendering performance has been compared between different graphics hardware.

This report describes a system for verification of fingerprints against a previous created template. It describes how and why a fingerprint image must be processed before it can be used to either identify or verify a person. The method is based on special features of a fingerprint, called minutiae points. The whole process from image to matching is described, every step in the process with image enhancement, binarization, thinning and how to find the minutiae points. Also what false minutiae points are, how they arise, why they deteriorate the result, and how to handle them, is discussed. Finally a test of the system with a large number of fingerprints is presented, to see how good the system is according to security and reliability about not accepting prints from other fingers or reject the fingerprints, which are from the same finger as the template. Many proposals about how the performance and the security of the system can be improved are also presented.

We present a concept for using procedural techniques to represent media. Procedural methods allow us to represent digital media (2D images, 3D environments etc.) with very little information and to render it photo realistically. Since not all kind of content can be created procedurally, traditional media representations (bitmaps, polygons etc.) must be used as well. We have adopted an object-based media representation where an object can be represented either with a procedure or with its traditional representation. Since the objects are created on the client the procedures can be adapted to its properties such as screen resolution and rendering performance. To keep the application as small and flexible as possible, each procedure is implemented as a library which is only loaded when needed. The media representation iswritten in XML to make it human readable and easy editable. The application is document driven where the content of the XML document determines which libraries to be loaded. The media objects resulting from the procedures is composited into the media representation preferred by the renderer together with the non-procedural objects. The parameters in the XML document are relative to parameters determined by the system properties (resolution, performance etc.) and hence adapt the procedures to the client. By mapping objects to individual libraries, the architecture is easy to make multi threaded and/or distributed.

The use of spectrophotometers for color measurements on printed substrates is widely spread among paper producers as well as within the printing industry. Spectrophotometer measurements are precise, but time-consuming procedures and faster methods are desirable. Previously presented work on color calibration of flatbed scanners has shown that they can be used for fast color measurements with acceptable results. Furthermore, the rapid development of digital cameras has made it possible to transfer the methods to a camera-based system, and in this work a moderately priced consumer digital camera is used for color measurements. Earlier presented methods for color calibration have been implemented in the camera-based system and new modifications that can improve their performance are proposed. Moreover, if the spectral sensitivities of the color filters in the camera sensor can be characterized, this can further improve the performance of the color measurements. Two methods for characterization of the color filters are presented in this work together with methods that use the camera characteristics for color measurements. The findings of this work show that a consumer digital camera can be used as a fast and inexpensive alternative to spectrophotometers for color measurements on printed substrates.

As air traffic is forecasted to increase, air traffic control software subsequently needs to be more sophisticated. To efficiently push development forward, testing is important in order to determine usability. The tests need to be adapted to fit a particular purpose and carried out with methods that preserve the validity of the results. This thesis describes an implementation project carried out at the EUROCONTROL Experimental Centre, Bretigny-sur-Orge, France. The purpose of the project is to create an application that enables a user to create datasets of air traffic to be used for these tests. The application allows for manual work or bulk imports from external data sources. Furthermore it compiles scenarios as output datasets intended for prototype air traffic control software developed at Linköping University. The application design rationale and development process is described. Some time is spent on demonstrating the flexibility of the application and how its usage fits in a bigger picture.

In this thesis some different modulation schemes for xDSL-techniques are compared. The investigated techniques are ADSL, G.lite, ADSL2, HDSL, SHDSL and VDSL. The modulation methods used are DMT, CAP and different versions of PAM. Several broadband techniques also use Trellis Coded Modulation (TCM) to increase the coding gain of the transmission. For each one of the different modulation methods the signal-to-noise ratio is calculated for generating a bit error rate probability of 10-7. This is the error rate that is demanded for several of the investigated standards. Comparison is also made of the transmission capacity of the channel and how sensitive the technique is for interference in a part of the frequency band. To compare the different modulation techniques, simulations of the modulations were made. The simulations were made with MatLab and Simulink. Unfortunately Simulink only supports one- and two-dimensional TCM. Therefore no good simulations of ADSL and ADSL2 with TCM were made, because those techniques use four-dimensional TCM.