Publicado em: 28/02/2012

Dissertação de Mestrado em Computação Gráfica

UNIVERSIDADE FEDERAL DO RIO GRANDE DO SUL
INSTITUTO DE INFORMÁTICA
PROGRAMA DE POS-GRADUAÇÃO EM COMPUTAÇÃO
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DEFESA DE DISSERTAÇÃO DE MESTRADO

Aluno: Vitor Augusto Machado Jorge
Orientador: Prof. Dr. Edson Prestes da Silva Júnior
Coorientadora: Profa. Dra. Luciana Porcher Nedel

Título: Color Wideline Detector and Local Width Estimation
Linha de Pesquisa: Computação Gráfica

Data: 01/03/2012
Hora: 10h
Local: Auditório José Mauro Volkmer de Castilho, Prédio 43424 – Instituto de Informática

Banca Examinadora:
Prof. Dr. Cláudio Rosito Jung (UFRGS)
Prof. Dr. Leandro Augusto Frata Fernandes (UFF)
Prof. Dr. Manuel Menezes de Oliveira Neto (UFRGS)

Presidente da Banca: Prof. Dr. Edson Prestes da Silva Júnior

Abstract:
Line detection algorithms are used by many application fields, such as computer vision and automation, as a basis for more complex analysis. For instance, line information can be used as input to object detection algorithms or even attitude estimation in flying robots. One way to detect lines is to use an isotropic nonlinear filtering procedure called the Wide Line Detector (WLD). This algorithm is effective to highlight the line pixels in gray scale images, separating dark or bright lines. However, line detection algorithms are not normally concerned with the pixel-wise estimation of the width. If available, such information could be further explored by computer vision algorithms. Furthermore, color is extensively used in computer vision as an object discriminant, but not by the WLD. In this Work, we propose the extension of the WLD to color images. We also develop a method that allows the estimation of the line width locally using only the density information and no border or center line information. Finally, we develop a new monotonically increasing kernel that is more efficient and yet is more robust to detect lines than the monotonically decreasing kernels used by the WLD.We perform several experiments that show the significance of the method.

Keywords:
Wide Line Detector, Color Wide Line Detector, Isotropic filtering, Local density estimate, Perceptual Color Differences.