29,545 research outputs found

    Contour Based 3D Biological Image Reconstruction and Partial Retrieval

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    Image segmentation is one of the most difficult tasks in image processing. Segmentation algorithms are generally based on searching a region where pixels share similar gray level intensity and satisfy a set of defined criteria. However, the segmented region cannot be used directly for partial image retrieval. In this dissertation, a Contour Based Image Structure (CBIS) model is introduced. In this model, images are divided into several objects defined by their bounding contours. The bounding contour structure allows individual object extraction, and partial object matching and retrieval from a standard CBIS image structure. The CBIS model allows the representation of 3D objects by their bounding contours which is suitable for parallel implementation particularly when extracting contour features and matching them for 3D images require heavy computations. This computational burden becomes worse for images with high resolution and large contour density. In this essence we designed two parallel algorithms; Contour Parallelization Algorithm (CPA) and Partial Retrieval Parallelization Algorithm (PRPA). Both algorithms have considerably improved the performance of CBIS for both contour shape matching as well as partial image retrieval. To improve the effectiveness of CBIS in segmenting images with inhomogeneous backgrounds we used the phase congruency invariant features of Fourier transform components to highlight boundaries of objects prior to extracting their contours. The contour matching process has also been improved by constructing a fuzzy contour matching system that allows unbiased matching decisions. Further improvements have been achieved through the use of a contour tailored Fourier descriptor to make translation and rotation invariance. It is proved to be suitable for general contour shape matching where translation, rotation, and scaling invariance are required. For those images which are hard to be classified by object contours such as bacterial images, we define a multi-level cosine transform to extract their texture features for image classification. The low frequency Discrete Cosine Transform coefficients and Zenike moments derived from images are trained by Support Vector Machine (SVM) to generate multiple classifiers

    Using contour information and segmentation for object registration, modeling and retrieval

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    This thesis considers different aspects of the utilization of contour information and syntactic and semantic image segmentation for object registration, modeling and retrieval in the context of content-based indexing and retrieval in large collections of images. Target applications include retrieval in collections of closed silhouettes, holistic w ord recognition in handwritten historical manuscripts and shape registration. Also, the thesis explores the feasibility of contour-based syntactic features for improving the correspondence of the output of bottom-up segmentation to semantic objects present in the scene and discusses the feasibility of different strategies for image analysis utilizing contour information, e.g. segmentation driven by visual features versus segmentation driven by shape models or semi-automatic in selected application scenarios. There are three contributions in this thesis. The first contribution considers structure analysis based on the shape and spatial configuration of image regions (socalled syntactic visual features) and their utilization for automatic image segmentation. The second contribution is the study of novel shape features, matching algorithms and similarity measures. Various applications of the proposed solutions are presented throughout the thesis providing the basis for the third contribution which is a discussion of the feasibility of different recognition strategies utilizing contour information. In each case, the performance and generality of the proposed approach has been analyzed based on extensive rigorous experimentation using as large as possible test collections

    Contour matching using ant colony optimization and curve evolution

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    Shape retrieval is a very important topic in computer vision. Image retrieval consists of selecting images that fulfil specific criteria from a collection of images. This thesis concentrates on contour-based image retrieval, in which we only explore the information located on the shape contour. There are many different kinds of shape retrieval methods. Most of the research in this field has till now concentrated on matching methods and how to achieve a meaningful correspondence. The matching process consist of finding correspondence between the points located on the designed contours. However, the huge number of incorporated points in the correspondence makes the matching process more complex. Furthermore, this scheme does not support computation of the correspondence intuitively without considering noise effect and distortions. Hence, heuristics methods are convoked to find acceptable solution. Moreover, some researches focus on improving polygonal modelling methods of a contour in such a way that the resulted contour is a good approximation of the original contour, which can be used to reduce the number of incorporated points in the matching. In this thesis, a novel approach for Ant Colony Optimization (ACO) contour matching that can be used to find an acceptable matching between contour shapes is developed. A polygonal evolution method proposed previously is selected to simplify the extracted contour. The main reason behind selecting this method is due to the use of a stopping criterion which must be predetermined. The match process is formulated as a Quadratic Assignment Problem (QAP) and resolved by using ACO. An approximated similarity is computed using original shape context descriptor and the Euclidean metric. The experimental results justify that the proposed approach is invariant to noise and distortions, and it is more robust to noise and distortion compared to the previously introduced Dominant Point (DP) Approach. This work serves as the fundamental study for assessing the Bender Test to diagnose dyslexic and non-dyslexic symptom in children

    Analisis Dan Implementasi Content Based Image Retrieval Berdasarkan Ciri Warna, Tekstur dan Bentuk

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    ABSTRAKSI: Kebutuhan akan sistem yang mampu melakukan pencarian image sesuai keinginan user dan seiring dengan terus berkembangnya ukuran basis data image membuat metode pencarian image dengan kata kunci berupa teks tidak lagi bisa diandalkan karena kata kunci yang diinputkan mungkin tidak sesuai dengan image yang diharapkan sehingga dengan memberikan kata kunci saja tidak cukup. Hal ini disebabkan pemberian nama image bisa bersifat tidak objektif.Dari permasalahan tersebut dibangunlah sistem yaitu Content Based Image Retrieval (CBIR) dengan menerapkan ekstraksi ciri warna (Color Moments), ciri tekstur (Haar Wavelet) dan ciri bentuk (Centroid Contour Distance) untuk mendapatkan image yang sesuai dengan image yang dicari. Ekstraksi fitur warna menggunakan Color Moments memanfaatkan distribusi probabilitas warna sebuah image yang terdiri dari 3 moments yaitu : mean, standard deviation, dan skewness. Sedangkan untuk ekstraksi tekstur dengan melakukan dekomposisi Haar Wavelet dengan pendekatan pyramid-structured wavelet transform (PWT) yang menghasilkan 12 fitur ciri. Untuk ekstraksi bentuk menggunakan Centroid Contour Distance dengan menghitung jarak dari centroid ke tepi objek dengan menggunakan perhitungan sudut 50 dan menghasilkan 72 fitur ciri.Hasil penelitian menunjukkan bahwa penggabungan ketiga metode secara paralel menghasilkan akurasi dan performansi yang lebih baik serta menghasilkan peningkatan nilai F-Measure dari pada penggabungan secara serial maupun individu. Akurasi yang diperoleh 96.39% dan performansi 43.77% serta selisih nilai F-Measure 19.65%.Kata Kunci : content based image retrieval, color moments, haar wavelet, centroid contour distance.ABSTRACT: Along with the continued development of image database making searching method a image based on keyword is not enough. Beacause, name of image can be given not objective.These problems built Content Based Image Retrieval based on color features extraction (Color Moments), texture features (Haar Wavelet) and shape features (Centroid Contour Distance) to obtained an appropriate with image query. Extraction of color features with Color Moments which is use a color probability distributions image that consist of 3 moments : mean, standar deviation and skewness.To extracting texture used decomposition Haar Wavelet approach pyramid-structured wavelet transform (PWT) which produces 12 feature texture. For shape extraction with Centroid Contour Distance calculating the distance from centroid to the edge of object. Calculating used angle 50 dan produces 72 shape feature.The result showed that paralel combination of 3 method has the accuracy and perfromance result better also increased value of F-Measures than serial combination or without combination. Accuracy obtained 96.39% and performance 43.77% with difference value of F-Measures 19.65%.Keyword: content based image retrieval, color moments, haar wavelet, centroid contour distance

    Plant image retrieval using color, shape and texture features

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    We present a content-based image retrieval system for plant image retrieval, intended especially for the house plant identification problem. A plant image consists of a collection of overlapping leaves and possibly flowers, which makes the problem challenging.We studied the suitability of various well-known color, shape and texture features for this problem, as well as introducing some new texture matching techniques and shape features. Feature extraction is applied after segmenting the plant region from the background using the max-flow min-cut technique. Results on a database of 380 plant images belonging to 78 different types of plants show promise of the proposed new techniques and the overall system: in 55% of the queries, the correct plant image is retrieved among the top-15 results. Furthermore, the accuracy goes up to 73% when a 132-image subset of well-segmented plant images are considered

    Corners-based composite descriptor for shapes

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    In this paper, a composite descriptor for shape retrieval is proposed. The composite descriptor is obtained based upon corner-points and shape region. In an earlier paper, we proposed a composite descriptor based on shape region and shape contour, however, the descriptor was not effective for all perspective and geometric transformations. Hence, we modify the composite descriptor by replacing contour features with corner-points features. The proposed descriptor is obtained from Generic FourierDescriptors (GFD) of the shape region and the GFD ofthe corner-points. We study the performance of the proposed composite descriptor. The proposed method is evaluated using Item S8 within the MPEG-7 Still Images Content Set. Experimental results show that the proposed descriptor is effective.<br /

    An Appearance-Based Framework for 3D Hand Shape Classification and Camera Viewpoint Estimation

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    An appearance-based framework for 3D hand shape classification and simultaneous camera viewpoint estimation is presented. Given an input image of a segmented hand, the most similar matches from a large database of synthetic hand images are retrieved. The ground truth labels of those matches, containing hand shape and camera viewpoint information, are returned by the system as estimates for the input image. Database retrieval is done hierarchically, by first quickly rejecting the vast majority of all database views, and then ranking the remaining candidates in order of similarity to the input. Four different similarity measures are employed, based on edge location, edge orientation, finger location and geometric moments.National Science Foundation (IIS-9912573, EIA-9809340

    Asymmetric Feature Maps with Application to Sketch Based Retrieval

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    We propose a novel concept of asymmetric feature maps (AFM), which allows to evaluate multiple kernels between a query and database entries without increasing the memory requirements. To demonstrate the advantages of the AFM method, we derive a short vector image representation that, due to asymmetric feature maps, supports efficient scale and translation invariant sketch-based image retrieval. Unlike most of the short-code based retrieval systems, the proposed method provides the query localization in the retrieved image. The efficiency of the search is boosted by approximating a 2D translation search via trigonometric polynomial of scores by 1D projections. The projections are a special case of AFM. An order of magnitude speed-up is achieved compared to traditional trigonometric polynomials. The results are boosted by an image-based average query expansion, exceeding significantly the state of the art on standard benchmarks.Comment: CVPR 201
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