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Reconstruction of optical pathlength distributions from images obtained by a wide‐field differential interference contrast microscope
Author(s) -
VAN MUNSTER E. B.,
VAN VLIET L. J.,
ATEN J. A.
Publication year - 1997
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1046/j.1365-2818.1997.2570815.x
Subject(s) - differential interference contrast microscopy , microscope , optics , interference (communication) , filter (signal processing) , optical microscope , interference microscopy , monochromatic color , bright field microscopy , microscopy , image processing , materials science , interferometry , physics , artificial intelligence , computer science , computer vision , image (mathematics) , channel (broadcasting) , scanning electron microscope , computer network
An image processing algorithm is presented to reconstruct optical pathlength distributions from images of nonabsorbing weak phase objects, obtained by a differential interference contrast (DIC) microscope, equipped with a charge‐coupled device camera. The method is demonstrated on DIC images of transparent latex spheres and unstained bovine spermatozoa. The images were obtained with a wide‐field DIC microscope, using monochromatic light. After image acquisition, the measured intensities were converted to pathlength differences. Filtering in the Fourier domain was applied to correct for the typical shadow‐cast effect of DIC images. The filter was constructed using the lateral shift introduced in the microscope, and parameters describing the spectral distribution of the signal‐to‐noise ratio. By varying these parameters and looking at the resulting images, an appropriate setting for the filter parameters was found. In the reconstructed image each grey value represents the optical pathlength at that particular location, enabling quantitative analysis of object parameters using standard image processing techniques. The advantage of using interferometric techniques is that measurements can be done on transparent objects, without staining, enabling observations on living cells. Quantitative use of images obtained by a wide‐field DIC microscope becomes possible with this technique, using relatively simple means.