Linking Multidimensional Feature Space Cluster Visualization to Multifield Surface Extraction

The problem of volume averaging in quantitating CSF, gray-matter, and white-matter fractions in the brain is solved using a three-compartment model and a simple graphical analysis of a multispectral MR feature space. Compartmentalization is achieved without the ambiguities of thresholding techniques or the need to assume that the underlying pixel probability distributions have a particular form. A 2D feature space is formed by double SE (proton density- and T2-weighted) MR data with image nonuniformity removed by a novel technique in which the brain itself serves as a uniformity reference. Compartments other than the basic three were rejected by the tailoring of limits in feature space. Phantom scans substantiate this approach, and the importance of the careful selection and standardization of pure tissue reference signals is demonstrated. Compartmental profiles from standardized subvolumes of three normal brains, based on a 3D (Talairach) coordinate system, demonstrate slice-by-slice detail; longitudinal studies confirm reproducibility. Compartmentalization may be described graphically and algebraically, complementing data displays in feature space and images of compartmentalized brain scans. These studies anticipate the application of our compartmentalization technique to patients with neurological disorders.

Intuitionistic Fuzzy C-means (IFCM) is a robust clustering method which is based upon intuitionistic fuzzy set theory. It uses Euclidean distance as a distance metric, hence can only cluster hyper spherically distributed data-sets in data space or in feature space. FCM and KFCM with a new distance measure (FCM-σ and KFCM-σ) can detect non-hyperspherical clusters in data space and feature space but they are sensitive to noise and produce inefficient results in the presence of noise. This paper present a robust Intuitionistic Fuzzy c-means(IFCM-σ) and a robust kernel Intutitionistic Fuzzy C-Means(KIFCM-σ) with a new distance metric that incorporates the distance variation in a cluster to regularize the distance between data point and the cluster centroid. Propose algorithms are the hybridization of IFCM, kernel function, and new distance metric in the data space and in the feature space which avoid various problems of IFCM and FCM-σ. Experiments are done using two-dimensional synthetic data-sets and noisy digital images, and results are compared with IFCM, KIFCM, FCM-σ and KFCM-σ. The results show that our proposed algorithms, especially KIFCM-σ are more effective.

This artificial visual system (AVS) is a computational framework for computer vision based on spatial filtering and statistical pattern recognition. Computer vision tasks are often poorly defined; the AVS clarifies the kinds of visual tasks that can be defined and what constitutes a well-defined task. `Segmentation'' is not a well-defined task. Edge detection is revealed to be an absurd task. A filter set composed of multiscale Gaussians alone captures the structure of Koenderink''s generic neighborhood operators when a pattern is constructed from the responses at a pixel and neighboring locations, where the distance to the selected neighbors increases with larger scale. Prior studies of the feature space formed by multiscale Gaussians reveal surprising power in the multiscale Gaussians alone. New studies support this observation. Contrary to common belief, we show how nonlocal, spatial, geometric structure can be captured using statistical pattern recognition operations in the AVS framework. A procedure is defined for deriving a single composite filter providing optimal separation of two clusters in feature space.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Recently, kernel-based clustering in feature space has shown to perform better than conventional clustering methods in unsupervised classification. In this paper, a partitioning clustering method i...

An unsupervised texture segmentation system using texture features obtained from a combination of spatial filters and nonlinear operators is described. Local texture features are evaluated in parallel by a succession of four basic operations: (1) a convolution for local structure detection (local linear transform); (2) a first nonlinearity of the form f(x)= mod x mod /sup alpha /; (3) an iterative smoothing operator; and (4) a second nonlinearity g(x). The Karhunen-Loeve transform is used to reduce the dimensionality of the resulting feature vector, and segmentation is achieved by thresholding or clustering in feature space. The combination of nonlinearities f(x)= mod x mod /sup alpha / (in particular, alpha =2) and g(x)=log x maximizes texture discrimination, and results in a description with variances approximately constant for all feature components and texture regions. This latter property improves the performance of both feature reduction and clustering algorithms significantly. >

Cluster analysis is an important and frequently-used data mining tool with a wide variety of research applications. There are numerous methods by which clusters in a dataset can be identified, with the majority of tools used for identifying statistical clusters in feature space. There also exists a specific subset of clustering approaches appropriate for the identification of spatial and spatiotemporal clusters with geographic data. The theory of these methods is presented here, as are common pitfalls and parameterization methods. This chapter concludes with a detailed discussion on how several different common spatial and spatiotemporal cluster analyses can be applied to different datasets.

Advances in mass spectrometry-based proteomics have yielded a substantial mapping of the tyrosine phosphoproteome and thus provided an important step toward a systematic analysis of intracellular signaling networks in higher eukaryotes. In this study we decomposed an uncharacterized proteomics data set of 481 unique phosphotyrosine (Tyr(P)) peptides by sequence similarity to known ligands of the Src homology 2 (SH2) and the phosphotyrosine binding (PTB) domains. From 20 clusters we extracted 16 known and four new interaction motifs. Using quantitative mass spectrometry we pulled down Tyr(P)-specific binding partners for peptides corresponding to the extracted motifs. We confirmed numerous previously known interaction motifs and found 15 new interactions mediated by phosphosites not previously known to bind SH2 or PTB. Remarkably, a novel hydrophobic N-terminal motif ((L/V/I)(L/V/I)pY) was identified and validated as a binding motif for the SH2 domain-containing inositol phosphatase SHIP2. Our decomposition of the in vivo Tyr(P) proteome furthermore suggests that two-thirds of the Tyr(P) sites mediate interaction, whereas the remaining third govern processes such as enzyme activation and nucleic acid binding.

Visual analytics of multidimensional multivariate data is a challenging task because of the difficulty in understanding metrics in attribute spaces with more than three dimensions. Frequently, the analysis goal is not to look into individual records but to understand the distribution of the records at large and to find clusters of records with similar attribute values. A large number of (typically hierarchical) clustering algorithms have been developed to group individual records to clusters of statistical significance. However, only few visualization techniques exist for further exploring and understanding the clustering results. We propose visualization and interaction methods for analyzing individual clusters as well as cluster distribution within and across levels in the cluster hierarchy. We also provide a clustering method that operates on density rather than individual records. To not restrict our search for clusters, we compute density in the given multidimensional multivariate space. Clusters are formed by areas of high density. We present an approach that automatically computes a hierarchical tree of high density clusters. To visually represent the cluster hierarchy, we present a 2D radial layout that supports an intuitive understanding of the distribution structure of the multidimensional multivariate data set. Individual clusters can be explored interactively using parallel coordinates when being selected in the cluster tree. Furthermore, we integrate circular parallel coordinates into the radial hierarchical cluster tree layout, which allows for the analysis of the overall cluster distribution. This visual representation supports the comprehension of the relations between clusters and the original attributes. The combination of the 2D radial layout and the circular parallel coordinates is used to overcome the overplotting problem of parallel coordinates when looking into data sets with many records. We apply an automatic coloring scheme based on the 2D radial layout of the hierarchical cluster tree encoding hue, saturation, and value of the HSV color space. The colors support linking the 2D radial layout to other views such as the standard parallel coordinates or, in case data is obtained from multidimensional spatial data, the distribution in object space.

Prompt learning automates the manual crafting of prompts for adapting vision-and-language models, to downstream tasks, particularly in few-shot scenarios. This paper addresses two key challenges in prompt learning: limited performance in one-shot settings and inefficient dataset construction from unlabeled data. To tackle these challenges, we visualize and compare CLIP's feature spaces after prompt learning under one-shot and 16-shot conditions, identifying necessary characteristics of feature spaces that yield better prompts. We propose two novel loss functions—Inclusive Loss and Exclusive Loss—that enhance accuracy in one-shot scenarios by encouraging the feature space to resemble those trained with sufficient data. Additionally, we investigate the distribution of image features within CLIP's feature space and introduce a sampling method called Cluster-Centroid Sampling (CCS). CCS constructs a more category-balanced dataset by selecting samples closest to cluster centroids. To validate our approaches, we conducted extensive experiments. First, we demonstrate the effectiveness of our proposed loss functions across multiple datasets, showing accuracy improvements in one-shot conditions. Second, we evaluate CCS using an unlabeled data pool, confirming its superiority over existing sampling methods in downstream task accuracy due to the construction of more balanced dataset.

A general nonparametric technique is proposed for the analysis of multi-resolution and multivariate feature space to isolate faulty sensors. The basic overlap function of the technique is an existing one-dimensional fault-detection Brooks-Iyengar algorithm which uses weighted precision and accuracy for static data. We prove the dual of the existing overlap function can isolate the measurement intervals in the multi-dimensional feature space for both labelled and unlabeled publicly available datasets. It is shown that computable complexity of learning the feature space increases linearly with the size of the input. The experimental results showed that by using mean average precision of all sensors using ensemble model for dynamic events. The proposed algorithm performed well in the presence of noise across many static and dynamic action recognition datasets.

This paper describes a new spatial-spectral feature extraction and selection technique for analysis and segmentation of the color images of natural scenes. It is a statistical-structural method which is developed by modeling several basic scene patterns such as uniformly colored object regions, textured image areas, and shadowed or highlighted image segments. The uniformly colored object parts are characterized by their spatial continuity property. The textured areas are identified by their spatial placement rules and spectral primitives. The shadowed and highlighted image segments are determined by their constant chromaticity and gradually varying lightness property. The basic rule used in this modelling process is the Julesz conjecture. The features are extracted by a simple averaging process in the local areas of these visual patterns, which are determined by the algorithm. This averaging process implicitly incorporates the spatial and spectral information contained in the local areas. Thus the extracted feature set is expected to provide better clustering in the feature space than the sensory data alone.

Standard clustering methods fail when data are characterized by non-linear associations. A suitable solution consists in mapping data in a higher dimensional feature space where clusters are separable. The aim of the present contribution is to propose a new technique in this context to identify interesting patterns in large datasets.

We present an automatic query expansion approach by generalizing the vector space model of information retrieval. In this framework, the images are presented by vectors of weighted concepts similar to the keyword-based representation in the text retrieval domain. The concepts comprise of color and texture patches from local image regions in a multi-dimensional feature space. To generate the concept vocabularies and represent the images, statistical model is built by utilizing a multi-class Support Vector Machine (SVM)-based classification technique. For automatic query expansion, the correlations between concepts are analyzed based on the neighborhood proximity between the concepts in encoded images by considering the local feedback information. The experimental results on a photographic image collection demonstrate the effectiveness of the proposed query expansion approaches.

Art effect generation from digital images using computational tools has been a hot research topic in recent years. We propose a new method for generating crystallization mosaic effects from color images. Two key problems in generating pleasant mosaic effect are studied: grouping pixels into mosaic tiles and arrangement of mosaic tiles adapting to image features. To give visually pleasant mosaic effect, we propose to create mosaic tiles by pixel clustering in feature space of color information, taking compactness of tiles into consideration as well. Moreover, we propose a method for processing feature boundaries in images which gives guidance for arranging mosaic tiles near image features. This method gives nearly uniform shape of mosaic tiles, adapting to feature lines in an esthetic way. The new approach considers both color distance and Euclidean distance of pixels, and thus is capable of giving mosaic tiles in a more pleasing manner. Some experiments are included to demonstrate the computational efficiency of the present method and its capability of generating visually pleasant mosaic tiles. Comparisons with existing approaches are also included to show the superiority of the new method.

This paper shows the impact of speaker normalization techniques, such as vocal tract length normalization (VTLN) and speaker-adaptive training (SAT), prior to discriminant feature space transforms, such as LDA (linear discriminant analysis). We demonstrate that removing the inter-speaker variability by using speaker compensation methods results in improved discrimination as measured by the LDA eigenvalues and also in improved classification accuracy (as measured by the word error rate). Experimental results on the SPINE (speech in noisy environments) database indicate an improvement of up to 5% relative over the standard case where speaker adaptation (during testing and training) is applied after the LDA transform which is trained in a speaker independent manner. We conjecture that performing linear discriminant analysis in a canonical feature space (or speaker normalized space) is more effective than LDA in a speaker independent space because the eigenvectors carve a subspace of maximum intra-speaker phonetic separability whereas in the latter case this subspace is also defined by the inter-speaker variability. Indeed, we show that the more normalization is performed (first VTLN, then SAT), the higher the LDA eigenvalues become.