A symbolic image database system is a system in which a large amount of image data and their related information are represented by both symbolic images and physical images. How to perceive spatial relationships among the components in a symbolic image is an important criterion to find a match between the symbolic image of the scene object and the one being store as a modal in the symbolic image database. Spatial reasoning techniques have been applied to pictorial database, in particular those using 2D strings as an index representation have been successful. In this thesis, we extend the existing three levels of type-i similarity to more levels to aid similarity retrieval more precisely. There are 13 spatial operators which were introduced by Lee and Hsu to completely represent spatial relationships in 1D space. But, they just combined the 13 spatial relationships on x- and y-axis to represent the spatial relationships in 2D space by 13 times 13 = 169 spatial relationships. However, the 169 spatial relationships are still not sufficient to show all kinds of spatial relationships between any two objects in 2D space. For example, the directional relationships, like North or South West, exist in 2D space and is difficult to be deducted from those 13 spatial operators. Thus, we add the nine directional relationships to the 169 spatial relationships in 2D space. In this way, we can distinguish up to 289 spatial relationships in 2D space. Moreover, in our proposed strategy, we also take care of the problem caused by the MBRs. In most of the previous approaches for iconic indexing, for simplifying the concerns, they apply the MBRs of two objects to define the spatial relationship between them. The topological relationships, however, between objects can be quite different from the spatial relationship of their respective $MBR$s. Therefore, sometimes, it is hard to correctly describe the spatial relationship of the objects in terms of the relationships between their corresponding MBRs. To improve this drawback resulted from MBRs, we adopting the concept of topological relationships in our proposed strategy. Good access methods for large image databases are important for efficient retrieval. The signature files can be viewed as a preselection searching filter to prune off the unsatisfied images. In order to solve the ambiguity of the MBRs and to present the spatial relationships in two dimensional space completely, we propose a hybrid approach-based signature extraction method for similarity retrieval. From our simulation study, we show that our approach can provide a higher rate of a correct match and requires a smaller storage cost than Lee et al.'s 2D B-based signature approach. In some case, the correct match rate based on our proposed strategy can be up to 42.18%, while it is just 16.66% in Lee et al.'s strategy. Moreover, the worst case of the storage cost required in our proposed strategy is 1686 bits. But, it always needs 2015 bits in Lee et al.'s strategy.

A symbolic image database system is a system in which a large amount of image data and their related information are represented by both symbolic images and physical images. Spatial relationships are important issues for similarity-based retrieval in many image database applications. How to perceive spatial relationships among the components in a symbolic image is an important criterion to find a match between the symbolic image of the scene object and the one being store as a modal in the symbolic image database. With the popularity of digital cameras and the related image processing software, a sequence of images are often rotated or flipped. That is, those images are transformed in the rotation orientation or the reflection direction. A robust spatial similarity framework should be able to recognize image variants such as translation, scaling, rotation, and arbitrary variants. Current retrieval by spatial similarity algorithms can be classified into symbolic projection methods, geometric methods, and graph-matching methods. Symbolic projection could preserve the useful spatial information of objects, such as width, height, and location. However, many iconic indexing strategies based on symbolic projection are sensitive to rotation or reflection. Therefore, these strategies may miss the qualified images, when the query is issued in the orientation different from the orientation of the database images. To solve this problem, researchers derived the rule of the change of spatial relationships in image transformation, and proposed a function to map the spatial relationship to its related transformed one. However, this mapping consists of several conditional statements, which is time-consuming. Thus, in this dissertation, first, we classify the mapping into three cases and carefully assign a 16-bit unique bit pattern to each spatial relationship. Based on the assignment, we can easily do the mapping through our proposed bit operation, intra-exchange, which is a CPU operation and needs only the complexity of O(1). Moreover, we propose an efficient iconic index strategy, called Unique Bit Pattern matrix strategy (UBP matrix strategy) to record the spatial information. In this way, when doing similarity retrieval, we do not need to reconstruct the original image from the UBP matrix in order to obtain the indexes of the rotated and flipped image. Conversely, we can directly derive the index of the rotated or flipped image from the index of the original one through bit operations and the matrix manipulation. Thus, our proposed strategy can do similarity retrieval without missing the qualified database images. In our performance study, first, we analyze the time complexity of the similarity retrieval process of our proposed strategy. Then, the efficiency of our proposed strategy according to the simulation results is presented. We show that our strategy outperforms those mapping strategies based on different number of objects in an image. According to the different number of objects in an image, the percentage of improvement is between 13.64% and 53.23%.

The improvements in 3D scanning technologies have led the necessity for managing range image databases. Hence, the requirement of describing and indexing this type of data arises. Up to now, rather much work is achieved on capturing, transmission and visualization / however, there is still a gap in the 3D semantic analysis between the requirements of the applications and the obtained results. In this thesis we studied 3D semantic analysis of range data. Under this broad title we address segmentation of range scenes, correspondence matching of range images and the similarity retrieval of range models. Inputs are considered as single view depth images. First, possible research topics related to 3D semantic analysis are introduced. Planar structure detection in range scenes are analyzed and some modifications on available methods are proposed. Also, a novel algorithm to segment 3D point cloud (obtained via TOF camera) into objects by using the spatial information is presented. We proposed a novel local range image matching method that combines 3D surface properties with the 2D scale invariant feature transform. Next, our proposal for retrieving similar models where the query and the database both consist of only range models is presented. Finally, analysis of heat diffusion process on range data is presented. Challenges and some experimental results are presented.

A possibilidade de recuperar e comparar imagens usando as suas características visuais intrínsecas é um recurso valioso para responder a consultas por similaridade em imagens médicas. Desse modo, a agregação desses recursos aos Sistemas de Arquivamento e Comunicação de Imagens (Picture Archiving and Communication Systems - PACS) vêm potencializar a utilidade e importância destes no contexto de atividades tais como ensino e treinamento de novos radiologistas, estudos de casos e auxílio ao diagnóstico de forma geral, uma vez que as consultas por similaridade permitem que casos parecidos possam ser facilmente recuperados. O trabalho apresentado nesta tese possui duas vertentes. Primeiro, ele apresenta novos métodos de extração e de características, com o objetivo de obter a essência das imagens, considerando um critério específico. Os atributos obtidos pelos algoritmos de extração são armazenados em vetores de características para posteriormente serem utilizados para indexar e recuperar as imagens baseando-se em seu conteúdo, para responder a consultas por similaridade. Há uma relação próxima entre os vetores de características e as funções de distância utilizadas para compará-los. Assim, a segunda parte deste trabalho trata da proposta, análise e comparação de novas famílias de funções de distância. As funções de distância propostas têm por objetivo tratar o problema do gap semântico, o qual representa o principal obstáculo das funções de distância tradicionais, derivadas da família Lp, quando processam consultas por similaridade. As principais contribuições desta tese incluem o desenvolvimento de novos métodos de extração e comparação de características de imagens, que operam sobre os três principais descritores de baixo nível de imagens: distribuição de cor, textura e forma. Os experimentos realizados mostraram que os ganhos em precisão são maiores para os métodos propostos, quando comparados com algoritmos tradicionais. No que diz respeito às famílias de funções de distância propostas (WAID e SAID), pelos resultados iniciais obtidos, podemos afirmar que eles são bastante promissores no sentido de se aproximarem da expectativa do usuário, no momento de comparar imagens. Os resultados obtidos com esse trabalho podem ser futuramente integrados aos PACS. Particularmente, pretendemos acrescentar novos algoritmos e métodos ao cbPACS, que consiste em um sistema PACS em construção, desenvolvido em uma colaboração entre o Grupo de Bases de Dados e Imagens (GBDI) do Instituto de Ciências Matemáticas e de Computação - USP e o Centro de Ciências da Imagens e Física Médica (CCIFM) da Faculdade de Medicina de Ribeirão Preto - USP / The ability of retrieving and comparing images using their inherent pictorial information is a valuable asset to answer similarity queries over medical images. Thus, having such resources added in Picture Archiving and Communication Systems (PACS) increase their applicability and importance in the context of teaching and training new radiologists on diagnosing, since that similar cases can be easily retrieved. Similarity queries also play an important role on gathering close images, what allows to perform case studies, as well as to aid on diagnosing. The work presented in this thesis is twofold. First, it presents new feature extraction techniques, which aim at obtaining the essence of the images regarding a given criteria. The features obtained by the algorithms are stored in feature vectors and employed to index and retrieve the images by content, in order to answer similarity queries. There is a close relationship among feature vectors and the distance function employed to compare them. Thus, the second, part of this work concerns the comparison, analysis and proposal of new families of distance functions to compare the features extracted from the images. The distance functions proposed intend to deal with the semantic gap problem, which is the main drawback of the traditional distance functions derived from the Lp metrics when processing similarity queries. The main contributions of this thesis include the development of new image feature extractors that works on the three aspects of raw image data (color distribution, texture and shape). The experiments have shown that the gain in precision are higher for all the feature extractors proposed, when comparing with the state-of-the-art algorithms. Regarding the two families of distance functions WAID and SAID proposed, by the initial experiments performed we can claim that they are very promising on preserving the user expectation when comparing images. The results provided by this work can be straightforwardly integrated to PACS. Particularly, we intend to add the new algorithms and methods to cbPACS, which is under joined development between the Image Data Base Group of Instituto de CiLncias Matemáticas e de Computaçno of USP and Centro de CiLncias de Imagens e Física Médica of Faculdade de Medicina de Ribeirno Preto of USP

A possibilidade de recuperar e comparar imagens usando as suas características visuais intrínsecas é um recurso valioso para responder a consultas por similaridade em imagens médicas. Desse modo, a agregação desses recursos aos Sistemas de Arquivamento e Comunicação de Imagens (Picture Archiving and Communication Systems - PACS) vêm potencializar a utilidade e importância destes no contexto de atividades tais como ensino e treinamento de novos radiologistas, estudos de casos e auxílio ao diagnóstico de forma geral, uma vez que as consultas por similaridade permitem que casos parecidos possam ser facilmente recuperados. O trabalho apresentado nesta tese possui duas vertentes. Primeiro, ele apresenta novos métodos de extração e de características, com o objetivo de obter a essência das imagens, considerando um critério específico. Os atributos obtidos pelos algoritmos de extração são armazenados em vetores de características para posteriormente serem utilizados para indexar e recuperar as imagens baseando-se em seu conteúdo, para responder a consultas por similaridade. Há uma relação próxima entre os vetores de características e as funções de distância utilizadas para compará-los. Assim, a segunda parte deste trabalho trata da proposta, análise e comparação de novas famílias de funções de distância. As funções de distância propostas têm por objetivo tratar o problema do gap semântico, o qual representa o principal obstáculo das funções de distância tradicionais, derivadas da família Lp, quando processam consultas por similaridade. As principais contribuições desta tese incluem o desenvolvimento de novos métodos de extração e comparação de características de imagens, que operam sobre os três principais descritores de baixo nível de imagens: distribuição de cor, textura e forma. Os experimentos realizados mostraram que os ganhos em precisão são maiores para os métodos propostos, quando comparados com algoritmos tradicionais. No que diz respeito às famílias de funções de distância propostas (WAID e SAID), pelos resultados iniciais obtidos, podemos afirmar que eles são bastante promissores no sentido de se aproximarem da expectativa do usuário, no momento de comparar imagens. Os resultados obtidos com esse trabalho podem ser futuramente integrados aos PACS. Particularmente, pretendemos acrescentar novos algoritmos e métodos ao cbPACS, que consiste em um sistema PACS em construção, desenvolvido em uma colaboração entre o Grupo de Bases de Dados e Imagens (GBDI) do Instituto de Ciências Matemáticas e de Computação - USP e o Centro de Ciências da Imagens e Física Médica (CCIFM) da Faculdade de Medicina de Ribeirão Preto - USP / The ability of retrieving and comparing images using their inherent pictorial information is a valuable asset to answer similarity queries over medical images. Thus, having such resources added in Picture Archiving and Communication Systems (PACS) increase their applicability and importance in the context of teaching and training new radiologists on diagnosing, since that similar cases can be easily retrieved. Similarity queries also play an important role on gathering close images, what allows to perform case studies, as well as to aid on diagnosing. The work presented in this thesis is twofold. First, it presents new feature extraction techniques, which aim at obtaining the essence of the images regarding a given criteria. The features obtained by the algorithms are stored in feature vectors and employed to index and retrieve the images by content, in order to answer similarity queries. There is a close relationship among feature vectors and the distance function employed to compare them. Thus, the second, part of this work concerns the comparison, analysis and proposal of new families of distance functions to compare the features extracted from the images. The distance functions proposed intend to deal with the semantic gap problem, which is the main drawback of the traditional distance functions derived from the Lp metrics when processing similarity queries. The main contributions of this thesis include the development of new image feature extractors that works on the three aspects of raw image data (color distribution, texture and shape). The experiments have shown that the gain in precision are higher for all the feature extractors proposed, when comparing with the state-of-the-art algorithms. Regarding the two families of distance functions WAID and SAID proposed, by the initial experiments performed we can claim that they are very promising on preserving the user expectation when comparing images. The results provided by this work can be straightforwardly integrated to PACS. Particularly, we intend to add the new algorithms and methods to cbPACS, which is under joined development between the Image Data Base Group of Instituto de CiLncias Matemáticas e de Computaçno of USP and Centro de CiLncias de Imagens e Física Médica of Faculdade de Medicina de Ribeirno Preto of USP

Problémy jako je jemnozrnná kategorizace či výpočty s využitím lidských zdrojů se v posledních letech v komunitě stávají stále populárnějšími, což dosvědčuje i značné množství publikací na tato témata. Zatímco většina těchto prací využívá "klasických'' obrazových příznaků extrahovaných počítačem, tato se zaměřuje především na percepční vlastnosti, které nemohou být snadno zachyceny počítači a vyžadují zapojení lidí do procesu sběru dat. Práce zkoumá možnosti levného a efektivního získávání percepčních podobností od uživatelů rovněž ve vztahu ke škálovatelnosti. Dále vyhodnocuje několik relevantních experimentů a představuje metody zlepšující efektivitu sběru dat. Jsou zde také shrnuty a porovnány metody učení multidimenzionálního indexování a prohledávání tohoto prostoru. Získané výsledky jsou následně užity v komplexním experimentu vyhodnoceném na datasetu obrázků jídel. Procedura začíná získáváním podobností od uživatelů, pokračuje vytvořením multidimenzionálního prostoru jídel a končí prohledáváním tohoto prostoru.