000 03037n a2200289#a 4500
001 40069
003 P5A
005 20230123132000.0
007 cr cuuuuuauuuu
008 210315s2020 bl por d
035 _aocm51338542
040 _aP5A
_cP5A
090 _atimpa
100 1 _aColunche, Juan Carlos Rojas
_91178
245 1 2 _aA new low-pass edge-aware filter that is invariant to scale and translation/
_cJuan Carlos Rojas Colunche.
246 1 1 _aUm novo filtro passa-baixa sensível a arestas, invariante por escala e por translação
260 _aRio de Janeiro:
_bIMPA,
_c2020.
300 _avideo online
500 _aDefesa de Tese Banca: Diego Nehab - Orientador - IMPA Luiz Henrique de Figueiredo - IMPA Benar Fux Svaiter - IMPA Ralph Teixeira - UFF Eduardo Gastal - UFRGS Leonardo Koller Sacht - Suplente - UFSC.
505 1 _aResumo: Removing high frequencies using low-pass linear and translation-invariant (LTI) filters is the most prevalent method to avoid aliasing. However, LTI filters couple sharpness to an oscillatory nature, which forces the choice between ringing or excessive smoothing. In this work, we discuss nonlinear filters which remove detail but preserve edges. Nonlinear filters can be sharp without introducing oscillations. However, they are more difficult to use and are not well understood. To solve this problem, we propose nonlinear filters that preserve the properties of LTI filters as much as possible. In particular, we start from the analysis of the recent Rolling Guidance Filter (RGF), including its behavior under translation and domain and range scaling, and obtain the conditions under which they converge uniformly. We also make an empirical analysis based on test images, identifying different problems. Among them, issues on the approximation of smooth regions, oversharpening, inconsistent edge preservation with the number of iterations or local contrast variations, and the need for an input-dependent parameter calibration. We then propose a new nonlinear filter, the Adaptive Regularized Rolling Guidance Filter (ARRGF), that does not suffer from these issues. In particular, it is range-scaling invariant and preserves smooth regions without excessive edge oversharpening. This way, it preserves edges throughout the image, independently of local contrast levels. We also make an empirical analysis based on test images, finding a single set of parameters that work well for a wide range of input images. Finally, we identify some of its limitations and propose topics for future work .
650 0 4 _aMatematica.
_2larpcal
_919899
697 _aTeses do IMPA
_924311
700 1 _aNehab, Diego Fernandes.
_u(IMPA)
_eorientador
_95301
711 2 _aDefesa de Tese
_910070
856 4 _zVIDEO
_uhttps://bit.ly/3eZ7z6e
942 _2impa
_cVIDEO
999 _aA NEW low-pass edge-aware filter that is invariant to scale and translation. Juan Carlos Rojas Colunche. Rio de Janeiro: IMPA, 2020. video online. Disponível em: <https://bit.ly/3eZ7z6e>. Acesso em: 26 jun. 2020.
_c38711
_d38711