This thesis deals with the development and evaluation of blind discrete cosine transform-based watermarking algorithms for copyright protection of digital still images using handwritten signatures and mobile phone numbers. The new algorithms take into account the perceptual capacity of each low frequency coefficients inside the Discrete Cosine Transform (DCT) blocks before embedding the watermark information. They are suitable for grey-scale and colour images. Handwritten signatures are used instead of pseudo random numbers. The watermark is inserted in the green channel of the RGB colour images and the luminance channel of the YCrCb images. Mobile phone numbers are used as watermarks for images captured by mobile phone cameras. The information is embedded multiple-times and a shuffling scheme is applied to ensure that no spatial correlation exists between the original host image and the multiple watermark copies. Multiple embedding will increase the robustness of the watermark against attacks since each watermark will be individually reconstructed and verified before applying an averaging process. The averaging process has managed to reduce the amount of errors of the extracted information. The developed watermarking methods are shown to be robust against JPEG compression, removal attack, additive noise, cropping, scaling, small degrees of rotation, affine, contrast enhancements, low-pass, median filtering and Stirmark attacks. The algorithms have been examined using a library of approximately 40 colour images of size 512 512 with 24 bits per pixel and their grey-scale versions. Several evaluation techniques were used in the experiment with different watermarking strengths and different signature sizes. These include the peak signal to noise ratio, normalized correlation and structural similarity index measurements. The performance of the proposed algorithms has been compared to other algorithms and better invisibility qualities with stronger robustness have been achieved.

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Mapping images – when words don’t work. My master essay is a walking contradiction. It is an explanation of how a non-wordly thought process emerged – but explained in words. Words have never been my strong suit and in my essay I try to illustrate how I use images instead of words, mapping instead of structure, to escape the dictatorship of the written explanation. Where words have a certain linear structure from A to B my thought process is instead a juxtaposed jumble of heterogeneous elements that together create different associations in a rhizomatic and non-structured way. When I begin a project it is always the images that guide my idea instead of the idea guiding my images. In this way I let myself be seduced by the non-explainable atmosphere of the images. Instead of explanations I collect the images in big maps that have no clear beginning, middle or end. I let the images speak to each other, compliment or contrast one another. For me this is a way of keeping my work open as long as possible. As I work with video and narrative structure in the final product, the juxtaposing of images is a way of postponing and contrasting the more closed process of editing on a linear timeline.  I have a strong belief in the power of images. The old cliché ‘a picture says more than a thousand words’ still works for me, specifically because they don’t have to explain themselves or be ‘literal’ (in the literal sense of the word). They allow me to dwell in atmospheres, non-logic connections and open questions. Together, the mapping of images doesn’t create one clear design for my work, but a heterogeneous multiplicity of potential works to come. Sooner or later I have to take control of the process and be the dictator of the images. But my experience have taught me, that the more I allow the images to speak for themselves in all their ambivalence, the more I can infuse my final work with the same ambivalence and open-endedness. My works are not answers, but questions. And the collection of images that guide my work process let me keep asking the questions that words cannot formulate. The essay grabbles with these themes of words, images and process. As an illustration of my process, the essay is accompanied by a visual map, where I have tried to explain the associations that the images create for the theme of my work. I haven’t escaped the dictatorship of words yet, but maybe given the images their proper place within my work process. / A 4 channel video installation. Size on screens: 136 x 76 cm. Duration on video: 17 min. In a defenceless condition we enter a room. And they in us. All of the rooms. Sure, there are differences. Though it is not important here, not anymore anyway. It is not important, when you will not remember why you walked into the room to begin with. What got you to enter, and why do you stay. Moments that extends infinitely in time, expands and pushes away the oxygen in the room, like the last to experience before death is this strange, anaerobe environment. Two people are sitting in a room that changes looks six times. They are waiting, but no one knows what they are waiting for. While waiting they start to confess to each other, but never directly. In stead they try to explain and apologize their action without ever mentioning what the actions were.

The analysis techniques applied to DNA microarray images are under active development. As new techniques become available, it will be useful to apply them to existing microarray images to obtain more accurate results. The compression of these images can be a useful tool to alleviate the costs associated to their storage and transmission. The recently proposed Relative Quantizer (RQ) coder provides the most competitive lossy compression ratios while introducing only acceptable changes in the images. However, images compressed with the RQ coder can only be reconstructed with a limited quality, determined before compression. In this work, a progressive lossy-to-lossless scheme is presented to solve this problem. First, the regular structure of the RQ intervals is exploited to define a lossy-to-lossless coding algorithm called the Progressive RQ (PRQ) coder. Second, an enhanced version that prioritizes a region of interest, called the PRQ-region of interest (ROI) coder, is described. Experiments indicate that the PRQ coder offers progressivity with lossless and lossy coding performance almost identical to the best techniques in the literature, none of which is progressive. In turn, the PRQ-ROI exhibits very similar lossless coding results with better rate-distortion performance than both the RQ and PRQ coders.

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Cellists are interested in ways to produce the largest sound possible in order to meet modern acoustic challenges. This research examined cellists' lower body posture, how lower posture affected the manner in which the cello was held, and ultimately, what effect this had on the instrument's sound. Lower posture is significant because it affects sound production. This research analyzed cello treatises, images of prominent cellists, and conducted sound lab tests. The treatise and image research investigated how foot placement, endpin length, angle, and tilt of the cello affected the amount of leg contact with the instrument. The sound lab research used a bowing apparatus and audio software to measure the effect of leg contact on sound production. The results of this study showed that lower posture affected the amount of contact made between the player and cello. The sound lab tests revealed that less leg contact led to larger amplitudes produced by the cello. This research also discovered that the contact from each leg uniquely affected certain frequencies. Research on lower posture's effect on sound may benefit performing cellists, pedagogues, luthiers, and researchers.

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