Recovery of relative depth from a single observation using an uncalibrated (real-aperture) camera Vinay P. Namboodiri Subhasis Chaudhuri Department of Electrical Engineering Indian Institute of Technology, Bombay Powai, Mumbai 400076, India. CVPR 2008
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Recovery of relative depth from a single observation using an uncalibrated (real-aperture) camera Vinay P. Namboodiri Subhasis Chaudhuri Department of.
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Recovery of relative depth from a single observation using an uncalibrated(real-aperture) camera
Vinay P. Namboodiri Subhasis Chaudhuri Department of Electrical EngineeringIndian Institute of Technology, BombayPowai, Mumbai 400076, India.CVPR 2008
OutlineIntroductionDiffusion Based Modeling of
DefocusReverse Heat EquationDFD Using Graph CutsResultsAmbiguity in Depth Estimation
Using DefocusConclusion
IntroductionRecovering the depth layers in a scene
from a single defocused observation
Common resolution◦Multiple observations
This paper◦Single observation◦Uncalibrated camera
Diffusion Based Modeling of DefocusDepth from defocus
methodology(DFD)◦1987, Pentland
Point spread function (PSF)◦The resultant PSF has the general
shape of a 2-D Gaussian function
The resultant image
the blurred observation
the focused image of the scene
Reverse Heat Equation(1) can be formulated in terms of
the isotropic heat equation
The original image◦achieved by reversing time
the blurred observation
the diffusion coefficient
The breakdown of the heat
equation is indicated by the degeneration of the gradient
The relative depth in the scenethe approximate estimate of the depth at the location x
the reverse diffusion time at a location x
DFD Using Graph CutsThe depth estimate is further
refined by modeling the depth as a Markov random field(MRF)
ResultsA texture image from the Brodatz
texture database which is blurred with3 different blur regions
A general outdoor image
A sports scene
A complex lighting conditions
Ambiguity in Depth Estimation Using DefocusThe foreground is out of focus
and the background is in focus
The foreground is in focus and the background is out of focus
ConclusionThe reverse heat equation can be
used for restoring the image based on the amount of defocus blur
A graph cuts based method is proposed to estimate the depth in the scene thereby enforcing regularization