@InProceedings{TorrećoFern:2005:SiShDe,
author = "Torre{\~a}o, Jos{\'e} Ricardo de Almeida and Fernandes,
Jo{\~a}o Luiz",
affiliation = "Instituto de Computa{\c{c}}{\~a}o, Universidade Federal
Fluminense",
title = "Single-image shape from defocus",
booktitle = "Proceedings...",
year = "2005",
editor = "Rodrigues, Maria Andr{\'e}ia Formico and Frery, Alejandro
C{\'e}sar",
organization = "Brazilian Symposium on Computer Graphics and Image Processing, 18.
(SIBGRAPI)",
publisher = "IEEE Computer Society",
address = "Los Alamitos",
keywords = "shape from defocus, shape from shading.",
abstract = "The limited depth of field causes scene points at various
distances from a camera to be imaged with different amounts of
defocus. If images captured under different aperture settings are
available, the defocus measure can be estimated and used for 3D
scene reconstruction. Usually, defocusing is modeled by gaussian
convolution over local image patches, but the estimation of a
defocus measure based on that is hampered by the spurious
high-frequencies introduced by windowing. Here we show that this
can be ameliorated by the use of unnormalized gaussians, which
allow defocus estimation from the zero-frequency Fourier component
of the image patches, thus avoiding spurious high frequencies. As
our main contribution, we also show that the modified shape from
defocus approach can be extended to shape estimation from single
shading inputs. This is done by simulating an aperture change, via
gaussian convolution, in order to generate the second image
required for defocus estimation. As proven here, the
gaussian-blurred image carries an explicit depth-dependent blur
component - which is missing from an ideal shading input -, and
thus allows depth estimation as in the multi-image case.",
conference-location = "Natal, RN, Brazil",
conference-year = "9-12 Oct. 2005",
doi = "10.1109/SIBGRAPI.2005.47",
url = "http://dx.doi.org/10.1109/SIBGRAPI.2005.47",
language = "en",
ibi = "6qtX3pFwXQZeBBx/GGUru",
url = "http://urlib.net/ibi/6qtX3pFwXQZeBBx/GGUru",
targetfile = "torreaoj_defocus.pdf",
urlaccessdate = "2024, Apr. 29"
}