Efficient Similarity Point Set Registration by Transformation Decomposition

Point set registration is one of the basic problems in computer vision. When the overlap ratio between point sets is small or the relative transformation is large, local methods cannot guarantee the accuracy. However, the time complexity of the branch and bound (BnB) optimization used in most existing global methods is exponential in the dimensionality of parameter space. Therefore, seven-Degrees of Freedom (7-DoF) similarity transformation is a big challenge for BnB. In this paper, a novel rotation and scale invariant feature is introduced to decouple the optimization of translation, rotation, and scale in similarity point set registration, so that BnB optimization can be done in two lower dimensional spaces. With the transformation decomposition, the translation is first estimated and then the rotation is optimized by maximizing a robust objective function defined on consensus set. Finally, the scale is estimated according to the potential correspondences in the obtained consensus set. Experiments on synthetic data and clinical data show that our method is approximately two orders of magnitude faster than the state-of-the-art global method and more accurate than a typical local method. When the outlier ratio with respect to the inliers is up to 1.0, our method still achieves accurate registration.

STRUKTUR METAFORA DALAM WACANA NARASI [Methafor Structural in Naration Text]

This study aims to describe the structure of metaphor in terms of topic elements, elements of image and sense elements in the narrative discourse. The data source in this study was obtained from a book collection of short stories and books on life travel stories in the form of published autobiographical books. The data of this study is an expression of metaphor in the form of phrases. Data collection techniques are done by documentation techniques, reading techniques, and note taking techniques. The results of this study indicate the topic elements in the structure of metaphors in narrative discourse forming five comparative concepts, namely (1) the concept of comparison of nouns, (2) the concept of comparison of nouns, (3) the concept of adjective noun, (4) the concept of adjective comparison -nomina, and (5) the concept of adjective-verb comparison. Image elements found in metaphorical structures include animal image elements, synesthesia image elements, anthropomorphic image elements, and abstract to concrete image elements. In the sense element or similarity point in this study found four similarity point categories, namely (1) the point of independence based on equality, (2) the point of similarity based on the function equation, (3) the point of similarity based on the equation of motion or direction, and (4) point similarity based on the equation of action. Penelitian ini bertujuan mendeskripsikan struktur metafora yang ditinjau dari unsur topik, unsur citra dan unsur sense dalam wacana narasi. Sumber data dalam penelitian ini diperoleh dari buku kumpulan cerpen dan buku kisah perjalanan hidup dalam bentuk buku autobiografi yang telah diterbitkan. Data penelitian ini adalah ungkapan metafora dalam bentuk frasa. Teknik pengumpulan data dilakukan dengan teknik dokumentasi, teknik baca, dan teknik catat. Hasil penelitian ini menunjukkan unsur topik pada struktur metafora dalam wacana narasi membentuk lima konsep perbandingan yaitu (1) konsep perbandingan nomina-nomina, (2) konsep perbandingan nomina-verba, (3) konsep perbandingan nomina-adjektiva, (4) konsep perbandingan adjektiva-nomina, dan (5) konsep perbandingan adjektiva-verba. Unsur citra yang ditemukan dalam struktur metafora meliputi unsur citra hewan, unsur citra sinestesia, unsur citra antropomofik, dan unsur citra abstrak ke konkret. Pada unsur sense atau titik kemiripan dalam penelitian ini ditemukan empat kategori titik kemiripan, yaitu (1) titik kemiripan berdasarkan persamaan sifat, (2) titik kemiripan berdasarkan persamaan fungsi, (3) titik kemiripan berdasarkan persamaan gerak atau arah, dan (4) titik kemiripan berdasarkan persamaan tindakan.