Blur-kernel estimation from spectral irregularities

摘要

A method for deriving a blur kernel from a blurred image is provided herein. The method may include the following steps: obtaining a blurred image B, being a product of a blur kernel k applied to an original image I; calculating fθ(x)=Rd*Pθ(B)(x) for every angle θ, wherein R denotes an autocorrelation operator, Pθ denotes a projection operator of based on angle θ, and d denotes a one dimensional differentiation filter; estimating spectral power of the blur kernel based on a given support parameter; estimating the blur kernel k using a phase retrieval algorithm, based on the estimated spectral power of the blur kernel; updating the support parameters; and repeating the estimating of the spectral power, the estimating of the kernel and the updating of the support parameters in an iterative, to yield the blur kernel.

主权项

1. A method comprising:
obtaining a blurred image B, being a product of a blur kernel k applied to an original image I, wherein B and I are matrices representing pixel image arrays and k is a kernel of a matrix; calculating fθ(x)=Rd*Pθ(B)(x) for every angle θ, wherein R denotes an autocorrelation operator, Pθ denotes a projection operator of a two dimensional signal into one dimension based on angle θ, and d denotes a one dimensional differentiation filter applied to a product of the projection operator Pθ and the blurred image B; setting support parameters sθ to argminx fθ(x); estimating |{circumflex over (k)}|2 denoting a spectral power of the blur kernel based on a given support parameter; estimating the blur kernel k using a phase retrieval algorithm, based on the estimated spectral power of the blur kernel |{circumflex over (k)}|2; updating the support parameters sθ to argmaxx (RPθ(k)(x)>a·max(RPθ(k))), wherein a is constant number; and repeating the estimating of the spectral power |{circumflex over (k)}|2, the estimating of the kernel and the updating of the support parameters sθ in an expectation maximization (EM) procedure, to yield the blur kernel k.