A two-stage method to correct aberrations induced by slide slant in bright-field microscopy. (August 2016)

• Record Type: Journal Article
• Authors: Fan, Yilun; Bradley, Andrew P.
• Is Part Of: Micron. Volume 87(2016:Aug.)
• Page Start: 18
• Page End: 32
• Publication Date: 2016-08
• Subjects: Virtual microscopy -- Tilted plane parallel plate -- Coma aberration -- Phase deconvolution; Microscopy -- Periodicals; Electron Probe Microanalysis -- Periodicals; Microscopy -- Periodicals; Microscopie -- Périodiques; Microscopy; Periodicals; 502.82
• DOI: 10.1016/j.micron.2016.05.001
• Languages: English
• ISSNs: 0968-4328

Abstract

Abstract : Highlights: We developed a two-stage algorithm to correct the optical aberrations induced by slide slant. The first stage corrects the dominating coma aberration utilising phase deconvolution. The second stage recovers the lost image contrast and resolution utilising iterative intensity deconvolution. A calibration method using cytology specimen is developed to find the dominating coma aberration. The two-stage method is demonstrated to be effective with both simulation and real specimen data. Abstract: To achieve optimal image quality in bright field microscopy, the slide surface should be perpendicular to the optical axis of the microscope. However, in the recently proposed "slanted scan" slide acquisition technique, scan speed is increased by purposely slanting the slide by a small angle (of 3–5°) so that multiple focal depths can be imaged simultaneously. In this case, the slanted slide introduces a bend in the point spread function (PSF), resulting in a coma and other aberrations that degrade image quality. In this paper, we propose a two-stage deconvolution method specifically designed to correct the aberrations induced by a slanted scan, but with general applicability to high-resolution bright-field microscopy. Specifically, we initially apply phase deconvolution to correct the dominating coma aberration, before applying a conventional semi-blind deconvolution method to further improve image resolution and contrast. We also propose a novel method to estimate the degree of coma aberration and the PSF of the optics utilising actual cytology specimens. The efficacy of the proposed algorithm is demonstrated quantitatively on simulated data, against a ground-truth (object) image, and qualitatively on cervical cytology specimens. Results demonstrate both improved convergence speed of the two-stage approach, especially when correcting the bend in the PSF, and a resultant image quality that is comparable to a conventionally (flat) scanned specimen.