Fig 1.
Single-shot color Differential Phase Contrast (cDPC) microscopy.
a) Optical schematic of a brightfield microscope with a cDPC color filter placed at the back focal plane of the condenser in Köhler configuration. b) Installation in Nikon TE300 microscope condenser turret. c) Reconstruction: the captured color image is separated into its RGB components, which are then used to recover two unknowns (amplitude and phase) via a well-posed linear deconvolution. The sample is a micro-lens array (Fresnel Technologies 605). d) CAD model and image of fabricated cDPC insert.
Fig 2.
Transfer functions for amplitude and phase contrast in each cDPC color channel.
Left: spectral contribution of each illumination filter as captured by the camera’s Bayer pattern. The following columns show the components of the source represented in each image, and the amplitude and phase transfer functions in the spatial frequency domain. Bottom row: sum of each column, representing the calibrated and scaled source and the total coverage of amplitude and phase transfer functions, respectively.
Fig 3.
Experimental comparison of single-shot cDPC with monochromatic DPC and through-focus phase retrieval methods.
(Left) Source patterns. (Middle) Raw camera measurements. (Right) Recovered optical field. DPC methods (partially coherent) were acquired using a 20× 0.4 NA objective lens, while through-focus images (spatially coherent) were captured using 60× 0.8 NA, in order to ensure equal resolution in all cases.
Fig 4.
Raw data, phase and amplitude reconstructions, synthesized phase contrast and DIC images for various samples and magnifications: micro-lens array (4x 0.1 NA), wild-type c. elegans (10x 0.25 NA), HEK 293T cells (20× 0.4 NA), MCF7 cells (20× 0.4 NA).
Fig 5.
Experimental demonstration of motion blur reduction with cDPC vs. conventional DPC.
Our cDPC method results in significantly reduced motion blur artifacts due to its single-shot acquisition.
Fig 6.
Comparison of standard DIC and PhC images to their synthesized counterparts from cDPC.
Ground truth DIC images were acquired using a 20x 0.75 NA objective and phase contrast images using a 20x 0.4 NA PhC objective. cDPC images were acquired using a 20x 0.4 NA objective and our filter insert.