<p>För att kunna rekonstruera en tredimensionell volym av en hjärna avbildad med hjälp av magnetresonanstomografi (MRI) behöver man korrigera varje snittbild i förhållande till varandra, beroende på oundvikliga rörelser hos den röntgade patienten. Detta förfarande kallas bildregistrering och idag använder man sig primärt av en metod där en bild utses till referensbild och därefter anpassas närliggande bilder, som antas ha en minimal avvikelse, till referensen.</p><p>Syftet med detta examensarbete är att använda en annan metod vanligen utnyttjad inom datorseende för att estimera ett rörelsefält utifrån en vanlig videosekvens, genom att följa markörer som indikerar rörelse. Målet är att skapa en robust estimering av huvudets rörelse, som då kan användas för att skapa en mer noggrann korrigering och därmed också en bättre rekonstruktion.</p> / <p>Before reconstructing a three dimensional volume from an MR brain imaging sequence there is a need for aligning each slice, due to unavoidable movement of the patient during the scanning. This procedure is known as image registration and the method used primarily today is based on a selected slice being the reference slice and then registrating the neighbouring slices, which are assumed to be of minimal deviation.</p><p>The purpose of this thesis is to use another method commonly used in computer vision - to estimate the motion from a regular videosequence, by tracking markers indicating movement. The aim is to create a robust estimation of the movement of the head, which in turn can be used to create a more accurate alignment and volume.</p>

<p>This thesis investigates how disparity estimation may be used to visualize an object on a 3D-screen. The first part looks into different methods of disparity estimation, and the second part examines different ways to visualize an object from one or several stereo pairs and a disparity map. Input to the system is one or several stereo pairs, and output is a sequence of images of the input scene but from more angles. This sequence of images can be shown on Setred AB's 3D-screen. The system has high real time demands and the goal is to do the disparity estimation and visualization in real time.</p><p>In the first part of the thesis, three different ways to calculate disparity maps are implemented and compared. The three methods are correlation-based, local structure-based and phase-based techniques. The correlation-based methods cannot satisfy the real-time demands due to the large number of 2D-convolutions required per pixel. The local structure-based methods have too much noise and cannot satisfy the quality requirements. Therefore, the best method by far is the phase-based method. This method has been implemented in Matlab and C and comparisons between the different implementations are presented.</p><p>The quality of the disparity maps is satisfying, but the real-time demands cannot yet be fulfilled. The future work is therefore to optimize the C code and move some functions to a GPU, because a GPU can perform calculations in parallel with the CPU. Another reason is that many of the calculations are related to resizing and warping, which are well-suited to implementation on a GPU.</p>

<p>The possibility to use real-time computer vision in video sequences gives many opportunities for a system to interact with the environment. Possible ways for interaction are e.g. augmented reality like in the MATRIS project where the purpose is to add new objects into the video sequence, or surveillance where the purpose is to find abnormal events.</p><p>The increase of the speed of computers the last years has simplified this process and it is now possible to use at least some of the more advanced computer vision algorithms that are available. The computational speed of computers is however still a problem, for an efficient real-time system efficient code and methods are necessary. This thesis deals with both problems, one part is about efficient implementations using single instruction multiple data (SIMD) instructions and one part is about robust tracking.</p><p>An efficient real-time system requires efficient implementations of the used computer vision methods. Efficient implementations requires knowledge about the CPU and the possibilities given. In this thesis, one method called SIMD is explained. SIMD is useful when the same operation is applied to multiple data which usually is the case in computer vision, the same operation is executed on each pixel.</p><p>Following the position of a feature or object in a video sequence is called tracking. Tracking can be used for a number of applications. The application in this thesis is to use tracking for pose estimation. One way to do tracking is to cut out a small region around the feature, creating a patch and find the position on this patch in the other frames. To find the position, a measure of the difference between the patch and the image in a given position is used. This thesis thoroughly investigates the sum of absolute difference (SAD) error measure. The investigation involves different ways to improve the robustness and to decrease the average error. One method to estimate the average error, the covariance of the position error is proposed. An estimate of the average error is needed when different measurements are combined.</p><p>Finally, a system for camera pose estimation is presented. The computer vision part of this system is based on the result in this thesis. This presentation contains also a discussion about the result of this system.</p> / Report code: LIU-TEK-LIC-2007:5. The report code in the thesis is incorrect.

<p>Initially an analytical closed-form inverse kinematics solution for a 5 DOF robotic arm was developed and implemented. This analytical solution proved not to meet the accuracy required for the shape sorting puzzle setup used in the COSPAL (COgnitiveSystems using Perception-Action Learning) project [2]. The correctness of the analytic model could be confirmed through a simulated ideal robot and the source of the problem was deemed to be nonlinearities introduced by weak servos unable to compensate for the effect of gravity. Instead of developing a new analytical model that took the effect of gravity into account, which would be erroneous when the characteristics of the robotic arm changed, e.g. when picking up a heavy object, a learning approach was selected.</p><p>As learning method Locally Weighted Projection Regression (LWPR) [27] is used. It is an incremental supervised learning method and it is considered a state-ofthe-art method for function approximation in high dimensional spaces. LWPR is further combined with visual servoing. This allows for an improvement in accuracy by the use of visual feedback and the problems introduced by the weak servos can be solved. By combining the trained LWPR model with visual servoing, a high level of accuracy is reached, which is sufficient for the shape sorting puzzle setup used in COSPAL.</p>

<p>Coated solid bleached board belongs to the top-segment of paperboards. One important property of paperboard is the printability. In this diploma work a specific print defect, oriented mottle, has been studied in association with Iggesund Paperboard. The objectives of the work were to develop a method for analysis of the dark and light areas of oriented mottle, to analyse these areas, and to clarify the effect from the print, coating and paperboard surface related factors. This would clarify the origin of oriented mottle and predict oriented mottle on unprinted paperboard. The objectives were fulfilled by analysing the areas between the dark halftone dots, the amount of coating and the ink penetration, the micro roughness and the topography. The analysis of the areas between the dark halftone dots was performed on several samples and the results were compared regarding different properties. The other methods were only applied on a limited selection of samples. The results from the study showed that the intensity differences between the dark halftone dots were enhanced in the dark areas, the coating amount was lower in the dark areas and the ink did not penetrate into the paperboard. The other results showed that areas with high transmission corresponded to dark areas, smoother micro roughness, lower coating amount and high topography. A combination of the information from these properties might be used to predict oriented mottle. The oriented mottle is probably an optical phenomenon in half tone prints, and originates from variations in the coating and other paperboard properties.</p>

The first ad was published in Sweden 1645. Advertising itself is not a new phenomenon, it's just the conditions that has been changed. Today, advertising is a matter of course in our daily lives, every day we are exposed to thousands of messages that wants to persuade and convince us to consume. In this paper, we have looked into the semiotic and rhetorical tricks that are used for this particular persuasion, and we have investigated whether they have changed in the last 60 years or if the same tricks are still being used today. Our two hypotheses is: A) the rhetorical and semiotic basis of an ad looks the same today as 60 years ago. Despite the obvious difference in layout and graphic design, we believe that persuasion techniques in the form of semiotic and rhetorical character used to sell a product does not differ significantly for the past compared to today. B) Propaganda is used more often in ads from the past then in the ads of today. The purpose of this paper has been to examine whether these hypothesis are correct or not. Our conclusion was based on a qualitative image- and rhetoric analysis applied to six ads from the past (40’s, 50’s and 60’s) and six ads from the present (2010) and the research of how propaganda is used. It was concluded that the hypothesis was not true, instead, we could see during the sixties that led to a different type of ad, a type that is more consistent with today's ads.

Robotic automation has been a part of state-of-the-art manufacturing for many decades. Robotic manipulators are used for such tasks as welding, painting, pick and place tasks etc. Robotic manipulators are quite flexible and adaptable to new tasks, but a typical robot-based production cell requires extensive specification of the robot motion and construction of tools and fixtures for material handling. This incurs a large effort both in time and monetary expenses. The task of a vision system in this setting is to simplify the control and guidance of the robot and to reduce the need for supporting material handling machinery. This dissertation examines performance and properties of the current state-of-the-art local features within the setting of object pose estimation. This is done through an extensive set of experiments replicating various potential problems to which a vision system in a robotic cell could be subjected. The dissertation presents new local features which are shown to increase the performance of object pose estimation. A new local descriptor details how to use log-polar sampled image patches for truly rotational invariant matching. This representation is also extended to use a scale-space interest point detector which in turn makes it very competitive in our experiments. A number of variations of already available descriptors are constructed resulting in new and competitive features, among them a scale-space based Patch-duplet. In this dissertation a successful vision-based object pose estimation system is extended for multi-cue integration, yielding increased robustness and accuracy. Robustness is increased through algorithmic multi-cue integration, combining the individual strengths of multiple local features. Increased accuracy is achieved by utilizing manipulator movement and applying temporal multi-cue integration. This is implemented using a real flexible robotic manipulator arm. Besides work done on local features for ordinary image data a number of local features for range data has also been developed. This dissertation describes the theory behind and the application of the scene tensor to the problem of object pose estimation. The scene tensor is a fourth order tensor representation using projective geometry. It is shown how to use the scene tensor as a detector as well as how to apply it to the task of object pose estimation. The object pose estimation system is extended to work with 3D data. A novel way of handling sampling of range data when constructing a detector is discussed. A volume rasterization method is presented and the classic Harris detector is adapted to it. Finally, a novel region detector, called Maximally Robust Range Regions, is presented. All developed detectors are compared in a detector repeatability test.

Syftet med denna uppsats är att analysera hur män framställs i modebilder. Vi vill med hjälp av en kvalitativ undersökning tolka mäns yttre genom ett analysschema, som vi själva tagit fram. Genom att analysera åtta bilder ur två framstående herrmagasin i Sverige, King of Sweden och Man Magazine, kom vi fram till en framträdande bild av hur män ser ut i modebilder. Vi valde att använda oss av tidningarnas decembernummer, 2008.   Denna undersökning utgjorde även en analysering av vad maskulinitet är och hur det framställs i modebilder för herrmagasin. Urvalet gjordes utifrån oss själva där vi strategiskt valde ut bilderna, och vilka tidningar vi ansåg vara ledande på den svenska marknaden. Därefter valde vi att analysera fyra bilder som var professionellt framställda för ett varumärke och fyra bilder som var redaktionellt utförda. Nästa steg i undersökningen blev att bild för bild undersöka dem utifrån vårt analysschema för att sedan diskutera kring det vi har kommit fram till.   Vi eftersträvade även efter att se vilka likheter och skillnader det fanns mellan de två olika magasinen, om det överhuvudtaget fanns någon skillnad. Förutom det ville få reda på om bilderna hade ett viktigt budskap att säga betraktaren.   Det vi kom fram till i resultatet var att det fanns olika typer av mansideal i herrmagasinen. Beroende på hur vi själva tolkade bilderna framträdde män som vi ansåg var mer maskulina och män som starkt ledde in mot det feminina. Männen i de redaktionella bilderna var dock mer feminint klädda och blev stylade på ett mer feminint sätt exempelvis håret och ögonbrynen. Däremot tyckte vi att de professionella modebilderna var väldigt manliga och riktade sig mot machomännen och de män som är mycket måna om sitt utseende.

Denna kvalitativa studie undersöker hur bildlärare arbetar med bildanalys i kursen Bild i gymnasieskolan. I målen för kursen Bild står det klart och tydligt att eleverna skall ha kunskaper i analys och tolkning av olika bilder. Jag har inte funnit någon tidigare forskning om hur bildlärare arbetar med bildanalys i bildundervisning överhuvudtaget och anser det vara av vikt att undersöka hur målen realiseras ute på skolorna. De metoder som används är litteraturstudier och strukturerade intervjuer med bildlärare verksamma vid det estetiska programmet. Studien visar på att det finns såväl likheter som skillnader i hur bildanalys brukas i bildundervisningen. Skillnaderna är i stor mån marginella. Vidare påvisar resultatet att en existerande dualism mellan verbalspråklig verksamhet och praktisk handling inte bör göra sig gällande i skolan i stort.

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