ARRUDA, F. A. P. V.; http://lattes.cnpq.br/6388763736916508; ARRUDA, Francisco de Assis Pereira Vasconcelos de.
Résumé:
Non-photorealistic rendering (NPR) or stylized rendering is an important growing area
of Computer Graphics and Image Processing. NPR is mainly concerned with the
generation of images or videos that can have an expressive appeal with regards to the
display of features that convey emotions. Some research challenges include: (i)
coping with variations in the lighting conditions of the input video; (ii) demanding
computational requirements for video rendering; (iii) difficulties in parameter
adjustment for each compared approach for a wide range of input videos; (iv)
processing videos in a temporally coherent manner; (v) difficulties in the evaluation
process. In such a context, this thesis aims at the conception of an original approach
to generate stylized videos. The proposed approach was validated by means of a
software application, consisting of a six-step pipeline, based on the rendering of each
video frame by a modified anisotropic diffusion technique. More specifically, the
modifications include: (i) the replacement of the original edge stopping function; (ii)
the usage of edges to stylize and guide the diffusion process; (iii) the combination of
the detected edges and smoothing by anisotropic diffusion; and (iv) the increase of
the saturation and intraregional chromatic homogeneity of the obtained result. A
comparative, subjective experimental evaluation of the proposed approach and four
concurrent ones was performed, which was based on a user voting scheme. The goal
of the evaluation was to highlight improvements in the results of the proposed
approach. One-Way ANOVA F-tests followed with multiple means comparison tests,
were performed on the results. The proposed approach has obtained better results
compared to the four other approaches, regarding the direct visual preference,
improved edge definition and stylization. In addition, the results of the proposed
approach contain spurious artifacts and flickering which are equivalent with those
produced by the compared approaches.