Reference TypeConference Proceedings
Citation KeyTorreãoFern:2005:SiShDe
Author1 Torreão, José Ricardo de Almeida
2 Fernandes, João Luiz
Affiliation1 Instituto de Computação, Universidade Federal Fluminense
TitleSingle-image shape from defocus
Conference NameBrazilian Symposium on Computer Graphics and Image Processing, 18 (SIBGRAPI)
EditorRodrigues, Maria Andréia Formico
Frery, Alejandro César
Book TitleProceedings
Date9-12 Oct. 2005
Publisher CityLos Alamitos
PublisherIEEE Computer Society
Conference LocationNatal
Keywordsshape from defocus, shape from shading.
AbstractThe 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.
Tertiary TypeFull Paper
Size139 KiB
Number of Files1
Target Filetorreaoj_defocus.pdf
Last Update2005: administrator
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