Representação em multiplas escalas para identificação automatica de estruturas em imagens medicas / Multiscale representation for automatic identification of structures in medical images

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

The identification of structures is an important step for several applications in the field of medical imaging. The purpose of this thesis is to contribute to the field of identification in medical images. Its main goal is to propose a generic methodology for identification of structures by using a multiresolution approach, the scale-space. We evaluate the use of a data representation that allows the inclusion of a priori knowledge about the structures in several scales and we also develop the idea of an appropriate scale to perform the processing. The proposed methodology comprises the following steps: (i) creation of an image representation in several scales using the scale space theory. (ii) Then the images in all scales are inspected and relevant features are extracted; the output of this step is a tree structure that maps the relations of the detected features throughout the scale space; the representation serves as a guide to subsequent high level processing step, where a priori knowledge about the desired feature is modeled and included in the representation. (iii) The last step is the matching between the elements present in the built structure and a known pattern that describes the structure of interest. The proposed methodology is generic and the type of information to be used depends strongly on the application. In this Thesis, we built a prototype application in which we used geometric information for identification of organs in 2D phantom images that reproduces human anatomy. The results of applying this method to a set of images with different noise and contrast levels were quite satisfactory. The two initial steps of the method were also implemented for 3D images. New parameters can be easily included in the matching step for extension to 3D

ASSUNTO(S)

diagnostico por imagens representation scale space identificação identification of structures representação do conhecimento (sistemas especialistas) processamento de imagens auxiliado por computador image processing

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