Algorithms for super-resolution of images based on Sparse Representation and Manifolds

lmage super-resolution is defined as a class of techniques that enhance the spatial resolution of images. Super-resolution methods can be subdivided in single and multi image methods. This thesis focuses on developing algorithms based on mathematical theories for single image super­ resolution problems. lndeed, in arder to estimate an output image, we adopta mixed approach: i.e., we use both a dictionary of patches with sparsity constraints (typical of learning-based methods) and regularization terms (typical of reconstruction-based methods). Although the existing methods already per- form well, they do not take into account the geometry of the data to: regularize the solution, cluster data samples (samples are often clustered using algorithms with the Euclidean distance as a dissimilarity metric), learn dictionaries (they are often learned using PCA or K-SVD). Thus, state-of-the-art methods still suffer from shortcomings. In this work, we proposed three new methods to overcome these deficiencies. First, we developed SE-ASDS (a structure tensor based regularization term) in arder to improve the sharpness of edges. SE-ASDS achieves much better results than many state-of-the- art algorithms. Then, we proposed AGNN and GOC algorithms for determining a local subset of training samples from which a good local model can be computed for recon- structing a given input test sample, where we take into account the underlying geometry of the data. AGNN and GOC methods outperform spectral clustering, soft clustering, and geodesic distance based subset selection in most settings. Next, we proposed aSOB strategy which takes into account the geometry of the data and the dictionary size. The aSOB strategy outperforms both PCA and PGA methods. Finally, we combine all our methods in a unique algorithm, named G2SR. Our proposed G2SR algorithm shows better visual and quantitative results when compared to the results of state-of-the-art methods.

Ampliação vocabular: glossário de textos do livro didático de língua portuguesa "Vontade de saber português" do 9º ano

This research aimed to verify the vocabulary difficulties faced by 9th year students while understanding the didactic book of Portuguese Language (DBPL) “Vontade de Saber Português”, used at the Municipal School Sebastião Rangel. We noticed the students had some doubts concerning the unknown vocabulary in the texts and, therefore, in text comprehension. The hypothesis is that one “difficult” word and the lexicon used by DBPL author can disturb student comprehension. We adopted some action which could simplify the little vocabulary understanding and contributed to extend it. For that reason, the job was theoretically based on Biderman (1999), Barbosa (1989), Dias (2004), Krieger (2012), Coelho (1993) and on National Curriculum Parameters of Portuguese Language, aiming to ally theory and practice. The application methodology of the proposal was done in order to the students understand that the word needs to be adapted to its context. At the begging of the job, the students read the texts and took notes of the “difficult” words, selecting, corpus. We analyzed the doubts, registering them. Then, we showed to the students the classification of abbreviated words after each entry. The students separated the words for grammar classes – lexical words” (KRIEGER, 2012). Such words have a very significant meaning to the comprehension of the read texts, being interesting to take a look in online dictionaries. In the creative glossary, done by the students, the words were spread in alphabetical order. They transcript the part where was the word and copied again, substituting the word to a clearer word. Finally, we asked the students a writing production using five words from the glossary; we showed them that the meaning of the words is not found only in the dictionary, but they can be used in different contexts. In the analyzes, was discovered that there is one necessity of a pedagogic didactic work more effective with elementary school lexicon. Thus, this proposal is not a closed receipt, but the infield location allowed a reflexive pedagogic practice about lexicon education.