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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
501

Perception-based second generation image coding using variable resolution / Perceptionsbaserad andra generationens bildkodning med variabel upplösning

Rydell, Joakim January 2003 (has links)
<p>In ordinary image coding, the same image quality is obtained in all parts of an image. If it is known that there is only one viewer, and where in the image that viewer is focusing, the quality can be degraded in other parts of the image without incurring any perceptible coding artefacts. This master's thesispresents a coding scheme where an image is segmented into homogeneous regions which are then separately coded, and where knowledge about the user's focus point is used to obtain further data reduction. It is concluded that the coding performance does not quite reach the levels attained when applying focus-based quality degradation to coding schemes not based on segmentation.</p>
502

Learning object boundary detection from motion data

Ross, Michael G., Kaelbling, Leslie P. 01 1900 (has links)
This paper describes the initial results of a project to create a self-supervised algorithm for learning object segmentation from video data. Developmental psychology and computational experience have demonstrated that the motion segmentation of objects is a simpler, more primitive process than the detection of object boundaries by static image cues. Therefore, motion information provides a plausible supervision signal for learning the static boundary detection task and for evaluating performance on a test set. A video camera and previously developed background subtraction algorithms can automatically produce a large database of motion-segmented images for minimal cost. The purpose of this work is to use the information in such a database to learn how to detect the object boundaries in novel images using static information, such as color, texture, and shape. / Singapore-MIT Alliance (SMA)
503

Nonlinear Analog Networks for Image Smoothing and Segmentation

Lumsdaine, A., Wyatt, J.L., Jr., Elfadel, I.M. 01 January 1991 (has links)
Image smoothing and segmentation algorithms are frequently formulatedsas optimization problems. Linear and nonlinear (reciprocal) resistivesnetworks have solutions characterized by an extremum principle. Thus,sappropriately designed networks can automatically solve certainssmoothing and segmentation problems in robot vision. This papersconsiders switched linear resistive networks and nonlinear resistivesnetworks for such tasks. The latter network type is derived from thesformer via an intermediate stochastic formulation, and a new resultsrelating the solution sets of the two is given for the "zerostermperature'' limit. We then present simulation studies of severalscontinuation methods that can be gracefully implemented in analog VLSIsand that seem to give "good'' results for these non-convexsoptimization problems.
504

Data and Model-Driven Selection Using Color Regions

Syeda-Mahmood, Tanveer Fathima 01 February 1992 (has links)
A key problem in model-based object recognition is selection, namely, the problem of determining which regions in the image are likely to come from a single object. In this paper we present an approach that extracts and uses color region information to perform selection either based solely on image- data (data-driven), or based on the knowledge of the color description of the model (model -driven). The paper presents a method of perceptual color specification by color categories to extract perceptual color regions. It also discusses the utility of color-based selection in reducing the search involved in recognition.
505

Learning object segmentation from video data

Ross, Michael G., Kaelbling, Leslie Pack 08 September 2003 (has links)
This memo describes the initial results of a project to create a self-supervised algorithm for learning object segmentation from video data. Developmental psychology and computational experience have demonstrated that the motion segmentation of objects is a simpler, more primitive process than the detection of object boundaries by static image cues. Therefore, motion information provides a plausible supervision signal for learning the static boundary detection task and for evaluating performance on a test set. A video camera and previously developed background subtraction algorithms can automatically produce a large database of motion-segmented images for minimal cost. The purpose of this work is to use the information in such a database to learn how to detect the object boundaries in novel images using static information, such as color, texture, and shape. This work was funded in part by the Office of Naval Research contract #N00014-00-1-0298, in part by the Singapore-MIT Alliance agreement of 11/6/98, and in part by a National Science Foundation Graduate Student Fellowship.
506

Learning to segment texture in 2D vs. 3D : A comparative study

Oh, Se Jong 15 November 2004 (has links)
Texture boundary detection (or segmentation) is an important capability of the human visual system. Usually, texture segmentation is viewed as a 2D problem, as the definition of the problem itself assumes a 2D substrate. However, an interesting hypothesis emerges when we ask a question regarding the nature of textures: What are textures, and why did the ability to discriminate texture evolve or develop? A possible answer to this question is that textures naturally define physically distinct surfaces or objects, thus, we can hypothesize that 2D texture segmentation may be an outgrowth of the ability to discriminate surfaces in 3D. In this thesis, I investigated the relative difficulty of learning to segment textures in 2D vs. 3D configurations. It turns out that learning is faster and more accurate in 3D, very much in line with what was expected. Furthermore, I have shown that the learned ability to segment texture in 3D transfers well into 2D texture segmentation, but not the other way around, bolstering the initial hypothesis, and providing an alternative approach to the texture segmentation problem.
507

Optical Flow Based Structure from Motion

Zucchelli, Marco January 2002 (has links)
No description available.
508

Segmenting Hand-Drawn Strokes

Wolin, Aaron David 2010 May 1900 (has links)
Pen-based interfaces utilize sketch recognition so users can create and interact with complex, graphical systems via drawn input. In order for people to freely draw within these systems, users' drawing styles should not be constrained. The low-level techniques involved with sketch recognition must then be perfected, because poor low-level accuracy can impair a user's interaction experience. Corner finding, also known as stroke segmentation, is one of the first steps to free-form sketch recognition. Corner finding breaks a drawn stroke into a set of primitive symbols such as lines, arcs, and circles, so that the original stoke data can be transformed into a more machine-friendly format. By working with sketched primitives, drawn objects can then be described in a visual language, noting what primitive shapes have been drawn and the shapes? geometric relationships to each other. We present three new corner finding techniques that improve segmentation accuracy. Our first technique, MergeCF, is a multi-primitive segmenter that splits drawn strokes into primitive lines and arcs. MergeCF eliminates extraneous primitives by merging them with their neighboring segments. Our second technique, ShortStraw, works with polyline-only data. Polyline segments are important since many domains use simple polyline symbols formed with squares, triangles, and arrows. Our ShortStraw algorithm is simple to implement, yet more powerful than previous polyline work in the corner finding literature. Lastly, we demonstrate how a combination technique can be used to pull the best corner finding results from multiple segmentation algorithms. This combination segmenter utilizes the best corners found from other segmentation techniques, eliminating many false negatives (missed primitive segmentations) from the final, low-level results. We will present the implementation and results from our new segmentation techniques, showing how they perform better than related work in the corner finding field. We will also discuss limitations of each technique, how we have sought to overcome those limitations, and where we believe the sketch recognition subfield of corner finding is headed.
509

How Nelo´s image is perceived in Germany : An empirical investigation amongst their agents

Bektesevic, Alisa, Oloya, Grace, Schöblom, Tom January 2009 (has links)
The purpose of this research was to investigate how the German market is segmented and what the German consumers perceive of Nelo’s positioning by assessment of what the Agents corroborate. The insights derived from it points out if Nelo’s image is rightly perceived in the German market.   In this paper a qualitative approach is used. Data collection method used was both interviews and documentation. Telephone interviews were conducted with three different agents operating in southern Germany. The secondary data the authors used were articles and books. Since it is a research based on a qualitative approach, the theories and the findings will be synthesized to make implication regarding the study.   The investigation has shown that the target segment for Nelo in Germany are the middle to high income group in the age 40+, but it is shown that the products offered by Nelo don’t attract this segment in southern Germany. Though product quality is good the design and material used, does not fit with the target customer rendering the brand unknown. Nelo is not well positioned in the target market because it has not been successful in communicating a clear image. To conclude Nelo´s position is not consistent with their image.
510

Airline Pricing Strategies : A comparison of German Lufthansa and Scandinavian Airline System / Airline Pricing Strategies : A comparison of German Lufthansa and Scandinavian Airline System

Lohmeier, Victoria, Hess, Simon January 2009 (has links)
<!--[if gte mso 10]> <mce:style><! /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Normale Tabelle"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} > <! [endif] > This paper focuses on the pricing strategies of international airlines, being the key factor to match the supply with demand and accomplish market equilibrium. The aim of study is to find a pattern of how pricing takes place, if and how airlines implement market segmentation and take demand-related elasticities into account. We specialize on the Scandinavian Airline System (SAS) and German Lufthansa. Their flight prices were collected as primary data from the corresponding websites. We observed the following air travel services: Long-haul international, short-haul international and short-haul domestic; additionally, we differentiated price levels by the time of booking. Based on our findings we can say that the market segmentation model provides a good base for airlines. However, it has to be accompanied by additional strategies to react to arising problems (peak problem, currency fluctuation, etc). The patterns we found implemented by SAS and Lufthansa represent a firm market-responsive approach to the problems in the airline industry. < >< ><-->

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