Perceptually-seductive technology (PST) is introduced as a way of designing IT environments that can help support everyday creativity. This is done in part by using sensory stimulation, seclusion and other perceptual components to seduce an individual towards creative insights that would not occur on the basis of conceptual thought alone. Everyday creativity is characterised as the combination of novel solutions in addressing everyday problems, and learning, indicating endurance over time. Everyday creativity is sometimes referred to as personal creativity, since it concerns what is novel to an individual, not to society as a whole. As in exceptional or historical creativity, in everyday creativity the novelty arises from the individual concerned, not from outside. Literature reviews of learning and memory, emotion and creativity set the scene and provide the basis for introducing PST. The relation of the individual to the technology, and with the world through the technology, is also considered. A model of the design space for PST is proposed and related to a proposed view of the creative process. It is suggested that to stimulate and support the creative process, IT environments should encourage both presence (perceptual or experiential mental activity) and absence (conceptual or reflective mental activity), which are seen as end points of a continuum comprising the Focus dimension. Similarly, the importance of both conscious and unconscious activity (the Sensus dimension) is emphasised, as is the role of emotion in mediating the balance between the two. The Locus dimension refers to the real-virtual distinction. In PST, virtual realisations are used to represent real world things and events and in so doing support the memorisation and reflection that are essential to everyday creativity. Four different examples of designing and implementing PST are presented. The first is a media production within a novel environment called the Interactive Tent, and is a demonstration and validation of theoretical ideas behind the PST concept. Three educational PST environments and their formative evaluations are then presented. These are first steps towards designing PST for particular kinds of application, in this case as environments for memorisation. Taken together, these examples lead to design recommendations and suggestions for future work, including the application of PST in education, stress management and for the elderly and disabled. / digitalisering@umu

Statistical graphics are often augmented by the use of color coding information contained in some variable. When this involves the shading of areas (and not only points or lines) - e.g., as in bar plots, pie charts, mosaic displays or heatmaps - it is important that the colors are perceptually based and do not introduce optical illusions or systematic bias. Here, we discuss how the perceptually-based Hue-Chroma-Luminance (HCL) color space can be used for deriving suitable color palettes for coding categorical data (qualitative palettes) and numerical variables (sequential and diverging palettes). / Series: Research Report Series / Department of Statistics and Mathematics

Statistical graphics are often augmented by the use of color coding information contained in some variable. When this involves the shading of areas (and not only points or lines) - e.g., as in bar plots, pie charts, mosaic displays or heatmaps - it is important that the colors are perceptually based and do not introduce optical illusions or systematic bias. Here, we discuss how the perceptually-based Hue-Chroma-Luminance (HCL) color space can be used for deriving suitable color palettes for coding categorical data (qualitative palettes) and numerical variables (sequential and diverging palettes). / Series: Research Report Series / Department of Statistics and Mathematics

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[pt] Nos últimos anos, diversas fórmulas de diferença de cores foram desenvolvidas para o espaço CIELAB, tais como CMC, CIE94 e CIEDE2000. Embora essas fórmulas obtenham maior precisão na medida perceptual entre cores, muitas aplicações não podem usufruir desta maior precisão, pois as distâncias euclidianas no CIELAB não são isométricas de acordo com essas novas fórmulas. Com isso, aplicações como gamut mapping e interpolação de cores precisam de um espaço de cores que seja isométrico em relação as fórmulas mais recentes de medição de diferenças de cores. Esse trabalho estuda o mapeamento do espaço CIELAB, em particular do plano ab deste espaço, sob a métrica da fórmula CIEDE2000, por meio de técnicas de escalonamento multidimensional, ou Multidimensional Scaling (MDS), tais como o ISOMAP e uma otimizaçãobaseada em Sammon Mapping. / [en] In recent years, various color difference formulas were developed for the CIELAB space, such as CMC, CIE94 and CIEDE2000. Although these formulas have achieved greater accuracy in perceptual measurement between colors, many applications cannot take advantage of this greater precision, because the Euclidean distances in CIELAB are not isometric in accordance with these new formulas. Thus, applications such as gamut mapping and color interpolation need a color space that is isometric in relation to the latest color difference formulas. This paper studies the mapping of the CIELAB space, particularly the ab plane of this space according to the metrics of the CIEDE2000 formula, through multidimensional scaling (MDS) techniques, more specifically ISOMAP and an optimization based on Sammon Mapping.

This work explores a novel vision model based coding approach to encode medical images at a perceptually lossless quality, within the framework of the JPEG 2000 coding engine. Perceptually lossless encoding offers the best of both worlds, delivering images free of visual distortions and at the same time providing significantly greater compression ratio gains over its information lossless counterparts. This is achieved through a visual pruning function, embedded with an advanced model of the human visual system to accurately identify and to efficiently remove visually irrelevant/insignificant information. In addition, it maintains bit-stream compliance with the JPEG 2000 coding framework and subsequently is compliant with the Digital Communications in Medicine standard (DICOM). Equally, the pruning function is applicable to other Discrete Wavelet Transform based image coders, e.g., The Set Partitioning in Hierarchical Trees. Further significant coding gains are ex ploited through an artificial edge segmentation algorithm and a novel arithmetic pruning algorithm. The coding effectiveness and qualitative consistency of the algorithm is evaluated through a double-blind subjective assessment with 31 medical experts, performed using a novel 2-staged forced choice assessment that was devised for medical experts, offering the benefits of greater robustness and accuracy in measuring subjective responses. The assessment showed that no differences of statistical significance were perceivable between the original images and the images encoded by the proposed coder.

The objective of the dissertation research is to investigate noise reduction methods for binaural hearing aids based on array and statistical signal processing and inspired by a human auditory model. In digital hearing aids, wide dynamic range compression (WDRC) is the most successful technique to deal with monaural hearing losses. This WDRC processing is usually performed after a monaural noise reduction algorithm. When hearing losses are present in both ears, i.e., a binaural hearing loss, independent monaural hearing aids have been shown not to be comfortable for most users, preferring a processing that involves synchronization between both hearing devices. In addition, psycho-acoustical studies have identified that under hostile environments, e.g., babble noise at very low SNR conditions, users prefer to use linear amplification rather than WDRC. In this sense, the noise reduction algorithm becomes an important component of a digital hearing aid to provide improvement in speech intelligibility and user comfort. Including a wireless link between both hearing aids offers new ways to implement more efficient methods to reduce the background noise and coordinate processing for the two ears. This approach, called binaural hearing aid, has been recently introduced in some commercial products but using very simple processing strategies. This research analyzes the existing binaural noise-reduction techniques, proposes novel perceptually-inspired methods based on blind source separation (BSS) and multichannel Wiener filter (MWF), and identifies different strategies for the real-time implementation of these methods. The proposed methods perform efficient spatial filtering, improve SNR and speech intelligibility, minimize block processing artifacts, and can be implemented in low-power architectures.