4,848 research outputs found
Sparse Modeling for Image and Vision Processing
In recent years, a large amount of multi-disciplinary research has been
conducted on sparse models and their applications. In statistics and machine
learning, the sparsity principle is used to perform model selection---that is,
automatically selecting a simple model among a large collection of them. In
signal processing, sparse coding consists of representing data with linear
combinations of a few dictionary elements. Subsequently, the corresponding
tools have been widely adopted by several scientific communities such as
neuroscience, bioinformatics, or computer vision. The goal of this monograph is
to offer a self-contained view of sparse modeling for visual recognition and
image processing. More specifically, we focus on applications where the
dictionary is learned and adapted to data, yielding a compact representation
that has been successful in various contexts.Comment: 205 pages, to appear in Foundations and Trends in Computer Graphics
and Visio
Hyperspectral colon tissue cell classification
A novel algorithm to discriminate between normal and malignant tissue cells of the human colon is presented. The microscopic level images of human colon tissue cells were acquired using hyperspectral imaging technology at contiguous wavelength intervals of visible light. While hyperspectral imagery data provides a wealth of information, its large size normally means high computational processing complexity. Several methods exist to avoid the so-called curse of dimensionality and hence reduce the computational complexity. In this study, we experimented with Principal Component Analysis (PCA) and two modifications of Independent Component Analysis (ICA). In the first stage of the algorithm, the extracted components are used to separate four constituent parts of the colon tissue: nuclei, cytoplasm, lamina propria, and lumen. The segmentation is performed in an unsupervised fashion using the nearest centroid clustering algorithm. The segmented image is further used, in the second stage of the classification algorithm, to exploit the spatial relationship between the labeled constituent parts. Experimental results using supervised Support Vector Machines (SVM) classification based on multiscale morphological features reveal the discrimination between normal and malignant tissue cells with a reasonable degree of accuracy
Hubungan gaya pembelajaran dengan pencapaian akademik pelajar aliran vokasional
Analisis keputusan Sijil Pelajaran Malaysia (SPM) 2011 menunjukkan penurunan
pencapaian bagi Sekolah Menengah Vokasional. Oleh itu, kajian ini dilaksanakan
bertujuan untuk mengkaji hubungan di antara gaya pembelajaran dengan pencapaian
akademik pelajar. Kajian ini juga ingin mengenalpasti gaya pembelajaran paling
dominan yang diamalkan oleh pelajar serta melihat perbezaan gaya pembelajaran
dengan jantina pelajar. Seramai 131 orang Pelajar Tingkatan Empat Kursus
Vokasional Di Sekolah Menengah Vokasional Segamat di Johor telah terlibat dalam
kajian ini. Soal selidik Index of Learning Style (ILS) yang dibangunkan oleh Felder
dan Silverman (1991) yang mengandungi 44 soalan telah digunakan untukh
menjalankan kajian ini. Gaya pembelajaran pelajar dapat dilihat melalui empat
dimensi gaya pembelajaran yang terdiri dari dua sub-skala yang bertentangan iaitu
dimensi pelajar Aktif dan Reflektif, dimensi pelajar Konkrit dan Intuitif, dimensi
pelajar Verbal dan Visual, serta dimensi pelajar Tersusun dan Global. Data yang
diperolehi dianalisis dengan menggunakan perisian Statistical Package for Social
Science for WINDOW release 20.0 (SPSS.20.0). Ujian Korelasi Pearson digunakan
untuk menganalisis data dalam mengkaji hubungan gaya pembelajaran dengan
pencapaian akademik pelajar. Nilai pekali p yang diperolehi di antara gaya
pembelajaran dengan pencapaian pelajar adalah (p=0.1 hingga 0.4). Ini menunjukkan
tidak terdapat hubungan yang signifikan di antara dua pembolehubah tersebut. Kajian
ini juga mendapati bahawa gaya pembelajaran yang menjadi amalan pelajar ialah
gaya pembelajaran Tersusun. Hasil kajian juga mendapati bahawa tidak terdapat
perbezaan yang signifikan di antara gaya pembelajaran dengan jantina pelajar
Selection of Wavelet Subbands Using Genetic Algorithm for Face Recognition
Abstract. In this paper, a novel representation called the subband face is proposed for face recognition. The subband face is generated from selected subbands obtained using wavelet decomposition of the original face image. It is surmised that certain subbands contain information that is more significant for discriminating faces than other subbands. The problem of subband selection is cast as a combinatorial optimization problem and genetic algorithm (GA) is used to find the optimum subband combination by maximizing Fisher ratio of the training features. The performance of the GA selected subband face is evaluated using three face databases and compared with other wavelet-based representations.
Wavelet Neural Networks: A Practical Guide
Wavelet networks (WNs) are a new class of networks which have been used with great success in a wide range of application. However a general accepted framework for applying WNs is missing from the literature. In this study, we present a complete statistical model identification framework in order to apply WNs in various applications. The following subjects were thorough examined: the structure of a WN, training methods, initialization algorithms, variable significance and variable selection algorithms, model selection methods and finally methods to construct confidence and prediction intervals. In addition the complexity of each algorithm is discussed. Our proposed framework was tested in two simulated cases, in one chaotic time series described by the Mackey-Glass equation and in three real datasets described by daily temperatures in Berlin, daily wind speeds in New York and breast cancer classification. Our results have shown that the proposed algorithms produce stable and robust results indicating that our proposed framework can be applied in various applications
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