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An efficient gradient-based method for differential-interference-contrast microscopy

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HAL Id: hal-01426337

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Submitted on 4 Jan 2017

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An efficient gradient-based method for

differential-interference-contrast microscopy

Simone Rebegoldi, Lola Bautista, Marco Prato, Luca Zanni, Laure

Blanc-Féraud, Arturo Plata

To cite this version:

Simone Rebegoldi, Lola Bautista, Marco Prato, Luca Zanni, Laure Blanc-Féraud, et al.. An efficient

gradient-based method for differential-interference-contrast microscopy. NUMTA 2016: Numerical

Computations: Theory and Algorithms, Jun 2016, Calabria, Italy. �hal-01426337�

(2)

An efficient gradient-based method for

differential-interference-contrast microscopy

Simone Rebegoldi, Lola Bautista, Marco Prato, Luca Zanni, Laure Blanc-F´eraud, Arturo Plata

Universit`a di Modena e Reggio Emilia, Via Campi 213/B, Modena, Italy Universidad Industrial de Santander, 680002 Bucaramanga, Colombia

Universit´e Nice Sophia Antipolis, 06903 Sophia Antipolis, France simone.rebegoldi@unimore.it, bautista@i3s.unice.fr,

marco.prato@unimore.it, luca.zanni@unimore.it, laure.blanc feraud@inria.fr, aplatag@yahoo.com

Keywords.DIC microscopy; inverse problems; gradient-descent method. Differential-interference-contrast (DIC) microscopy is an optical microscopy technique widely used in biology to observe unstained transparent specimens, in which a two-dimensional image is formed from the interference of two waves that have a lateral differential displacement (shear) and are phase shifted relative one to each other. Following the rotational-diversity model proposed in [1], one is interested in retrieving the specimen’s phase function from a set of DIC intensity images acquired at different rotations of the specimen. This highly nonlinear, ill-posed problem is solved by adopting a least squares approach and thus looking for a regularized solution of a smooth nonconvex optimization problem.

As already done in [1], one can address the DIC problem by means of a nonlinear conjugate gradient method, which is particularly suited for least squares prob-lems. However, the computation of the line search parameter at each iteration may require several evaluations of both the function and its gradient in order to ensure convergence [2], which significantly increases computational time when such evaluations are time-consuming, as is the case of the DIC problem. In this light we propose an efficient gradient-descent method for the estimation of a specimen’s phase function from polychromatic DIC images. The method min-imizes the sum of a nonlinear least-squares discrepancy measure and a smooth approximation of the total variation and exploits a recent updating rule for the choice of the step size [3]. Numerical simulations on two computer-generated objects show significant improvements in terms of efficiency and stability with respect to widely used conjugate gradient methods.

References

[1] Preza C. (2000) Rotational-diversity phase estimation from differential interference contrast microscopy images. J. Opt. Soc. Am. A, Vol. 17, no. 3, pp. 415–424. [2] J. C. Gilbert, J. Nocedal. (1992) Global convergence properties of conjugate

gra-dient methods for optimization. SIAM J. Optim., Vol. 2, No. 1, pp. 21–42. [3] R. Fletcher. (2012) A limited memory steepest descent method. Math. Program.,

Vol. 135, No. 1–2, pp. 413–436.

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