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  • Disputas: 2019-03-14 13:15 J1650, Karlskrona
    Wen, Wei
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för teknik och estetik.
    Biological Inspired Deformable Image Sensor2019Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Nowadays, cameras are everywhere thanks to the tremendous progress on sensor technology. However, their performance is far away from what we experience by our eyes. The study from evolution process shows how the sensor arrangement of retina in human vision has differentiated from other species and is formed into a specific combination of sub-arrangements from hexagonal to elliptical ones. There are three major key differences between our visual cell arrangement and current camera sensors which are: the sub-arrangements, the pixel form and the pixel density.

    Despite the advances in sensor technology we face limitations in their further development; i.e. to make the cameras close to the visual system. This is due to the optical diffraction limit which prevents us to increase the sensor resolution, and rigidity of hardware implementation which prevent us to change the image sensor after manufacturing. In the thesis the possibilities to overcome such limitations are investigated where the intention is to find a closer sensory solution to the visual system in comparison to the current ones.

    Breaking the diffraction barrier and solving the rigidity problem are simultaneously achieved by introducing and estimating virtual subpixels. A statistical framework consisting of local learning model and Bayesian inference for predicting the incident photons captured on each such a subpixel is used to resample the captured image by any current camera sensor. By investigating the virtual variation of pixel size and fill factor the validity of the proposed idea is proven by which the results show significant changes of dynamic range and tonal levels in relation to the variation. As an example, for both monochrome and color images the results show that by virtual increase of fill factor to 100%, the dynamic range of the images are widened and the tonal levels are enriched significantly over 256 levels for each channel.

    The results of virtual variation of the fill factor and pixel size indicates that it is feasible to change the rigidity of the image sensor using the software-based method. Inspired by the mosaic in the fovea, the center of human retina, the hexagonal sub-arrangement and pixel form are proposed to generate images based on the estimated virtual subpixels. Compared to the original square images, not only the dynamic range and tonal levels are improved, but also the hexagonal images are superior in detection of edges, i.e. more edge points on the contour of the objects are detected in hexagonal images.

    The evaluation of different sub-arrangements or pixel forms of the image sensor is a challenging task and should be directed to a more specific task. Since the curvature contours contain most of the information related to object perception and human vision is highly evolved to detect curvature object, the task is focused to investigate the impact of the curviness on the different pixel forms and sub-arrangements, by comparing two categories of images; having curved versus linear edges of the objects in a pair of images which have exact similar contents but different contours. The detectability of each of the different sensor structures for curviness is estimated and the results show that the image on hexagonal grid with hexagonal pixel form is the best image type for distinguishing the curvature contours in the images.

    According to the pattern of pixels tiling, there are two types of pixel sub-arrangements, i.e. periodic (e.g. square or hexagonal), and aperiodic (e.g. Penrose). Each type of sub-arrangements is investigated where the pixel forms and density are variable. By having at least two generated images of one configuration (i.e. specific sub-arrangement, pixel form and density), the result of histogram of gradient orientation of the certain sensor arrangement shows a stable and specific distribution which we called it the ANgular CHaracteristic of a sensOR structure (ANCHOR). Each ANCHOR has a robust pattern which is changed by the change of the sensor sub-arrangement. This makes it feasible to plan a sensor sub-arrangement in the relation to a specific application and its requirements, and more alike the biological vision sensory. To generate such a flexible sensor, a general framework is proposed for virtual deforming the sensor with a certain configuration of the sensor sub-arrangement, pixel form and pixel density.

    Assessing the quality difference between the images generated by different sensor configuration or addressing from on configuration to another one generally needs the conversion of one to another. To overcome this problem, a common space is proposed by implementing a continuous extension of square or hexagonal images based on the orbit function, for quality evaluating the images with different arrangements and addressing from one type of image to another one. The evaluation results show that the creation of such space is feasible which facilitates a usage friendly tool to address an arrangement and assess the changes between different spatial arrangements, for example, it shows richer intensity variation, nonlinear behavior, and larger dynamic range in the hexagonal images compared to the rectangular images.

  • Disputas: 2019-03-22 13:00 C446, Karlskrona
    Ankre, Rosemarie
    Mittuniversitetet.
    Friluftslivkonflikter i svenska kustlandskap ur ett planerings- och användarperspektiv: Studier av Luleå och Blekinge skärgårdar2019Doktoravhandling, monografi (Annet vitenskapelig)
    Abstract [sv]

    Hav och kust har alltid varit viktiga för oss människor. I svenska kustlandskap har boende, infrastruktur och fiskenäring existerat sedan lång tid tillbaka samtidigt som områdena också varit viktiga för nöje och rekreation. Men mellan olika intressen, samt mellan och inom olika användargrupper samt förvaltning, kan det uppstå målkonflikter. Utgångspunkten för den här avhandlingen är att beskriva och analysera eventuella målkonflikter kopplat till friluftsliv utifrån både ett planerings- och ett användarperspektiv genom två fallstudier i Luleå och Blekinge skärgårdar. Friluftslivet är en del av samhället och dess relevans för fysisk och mental återhämtning ger planering och förvaltning av friluftsliv ett ökat politiskt stöd, samtidigt som tidigare forskning visat att friluftsliv är stark i retoriken - men svag i planeringspraktiken. Därför behövs kunskap som kan utveckla planering och förvaltning av friluftsliv i svenska kustlandskap.

    Resultaten från den här avhandlingen visar att användarnas perspektiv på målkonflikter i Luleå och Blekinge skärgårdar ännu inte till stora delar har inkluderats i den kommunala planeringen. En slutsats är alltså att det finns skillnader i hur konflikter i samband med friluftsliv beskrivs och identifieras i den fysiska planeringen jämfört med användarnas upplevelser. Det har betydelse för förståelsen av friluftlivskonflikter och hanteringen av dessa. Förutom analys och diskussion av konflikter kopplat till friluftsliv, ingår en fördjupande studie av buller och tystnad som konflikt. Upplevelserna av lugn och ro samt tystnad är centrala för användarna i Luleå och Blekinge skärgårdar. Ett problem som avslöjas är att metoder med decibelnivåer inte avgör skillnader i buller som upplevelse i sig. Upplevelsen av buller och tystnad är nämligen subjektiv. Även zonering undersöks som ett planerings- och förvaltningsverktyg för att hantera friluftslivkonflikter i svenska kustlandskap. Som denna avhandling visar, finns det flertalet exempel på olika sorters zonering i Luleå och Blekinge skärgårdar. När man i planering och förvaltning utgår från ett perspektiv där naturvård och bevarande är utgångspunkterna, så måste ytterligare värderingar och verktyg inbegripas som att inkludera användare med deras olika behov, upplevelser och aktiviteter som äger rum i skärgårdarnas landskap. Att landskapet i sig är av betydelse syns också i resultaten. I fallstudiernas översiktsplaner markeras det värdefulla, attraktiva och unika med skärgårdslandskapet, medan användarna betonar det äkta, naturliga och opåverkade landskapet som grund för deras friluftsupplevelser.

    Den här avhandlingen tillför kunskap om spänningen mellan olika attityder och synsätt i den fysiska planeringens processer, förvaltning samt friluftslivets användare i svenska kustlandskap. Avhandlingen är också ett tillägg till tidigare kunskap om zonering som ett sätt att hantera konflikter i svenska kustlandskap, där särskilt användarperspektivet är en viktig del. Avhandlingen bidrar även till en grundläggande översikt av fysisk planering i relation till friluftsliv.

  • Disputas: 2019-03-29 23:01 Karlskrona
    Jerčić, Petar
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kreativa teknologier.
    The Effects of Emotions and Their Regulation on Decision-making Performance in Affective Serious Games2019Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Emotions are thought to be one of the key factors that critically influence human decision-making. Emotion-regulation can help to mitigate emotion-related decision biases and eventually lead to a better decision performance. Serious games emerged as a new angle introducing technological methods to practicing emotion-regulation, where meaningful biofeedback information communicates player's affective states to a series of informed gameplay choices. These findings motivate the notion that in the decision context of serious games, one would benefit from awareness and regulation of such emerging emotions.

    This thesis explores the design and evaluation methods for creating serious games where emotion-regulation can be practiced using physiological biofeedback measures. Furthermore, it investigates emotions and the effect of emotion-regulation on decision performance in serious games. Using the psychophysiological methods in the design of such games, emotions and their underlying neural mechanism have been explored.

    The results showed the benefits of practicing emotion-regulation in serious games, where decision-making performance was increased for the individuals who down-regulated high levels of arousal while having an experience of positive valence. Moreover, it increased also for the individuals who received the necessary biofeedback information. The results also suggested that emotion-regulation strategies (i.e., cognitive reappraisal) are highly dependent on the serious game context. Therefore, the reappraisal strategy was shown to benefit the decision-making tasks investigated in this thesis. The results further suggested that using psychophysiological methods in emotionally arousing serious games, the interplay between sympathetic and parasympathetic pathways could be mapped through the underlying emotions which activate those two pathways. Following this conjecture, the results identified the optimal arousal level for increased performance of an individual on a decision-making task, by carefully balancing the activation of those two pathways. The investigations also validated these findings in the collaborative serious game context, where the robot collaborators were found to elicit diverse affect in their human partners, influencing performance on a decision-making task. Furthermore, the evidence suggested that arousal is equally or more important than valence for the decision-making performance, but once optimal arousal has been reached, a further increase in performance may be achieved by regulating valence. Furthermore, the results showed that serious games designed in this thesis elicited high physiological arousal and positive valence. This makes them suitable as research platforms for the investigation of how these emotions influence the activation of sympathetic and parasympathetic pathways and influence performance on a decision-making task.

    Taking these findings into consideration, the serious games designed in this thesis allowed for the training of cognitive reappraisal emotion-regulation strategy on the decision-making tasks. This thesis suggests that using evaluated design and development methods, it is possible to design and develop serious games that provide a helpful environment where individuals could practice emotion-regulation through raising awareness of emotions, and subsequently improve their decision-making performance.