Real-time brightfield, darkfield, and phase contrast imaging in a light-emitting diode array microscope

Abstract

Abstract. We demonstrate a single-camera imaging system that can simultaneously acquire brightfield, darkfield, and phase contrast images in real time. Our method uses computational illumination via a programmable light-emitting diode (LED) array at the source plane, providing flexible patterning of illumination angles. Brightfield, darkfield, and differential phase contrast images are obtained by changing the LED patterns, without any moving parts. Previous work with LED array illumination was only valid for static samples because the hardware speed was not fast enough to meet real-time acquisition and processing requirements. Here, we time multiplex patterns for each of the three contrast modes in order to image dynamic biological processes in all three contrast modes simultaneously. We demonstrate multicontrast operation at the maximum frame rate of our camera (50 Hz with 2160 × 2560 pixels).

3D intensity and phase imaging from light field measurements in an LED array microscope

“…Our system is built on a commercial microscope in which the illumination unit has been replaced by a programmable LED array. This simple, inexpensive hardware modification enables not only 4D light field capture [35,38], but also dark field [38,39], phase contrast [35,39], Fourier ptychography [23,24], and digital aberration removal [40].…”

Quantitative phase recovery from asymmetric illumination on an LED array microscope

“…Each LED can be controlled individually to illuminate the sample from a unique angle. This simple, inexpensive hardware modification enables darkfield, 9,13 phase contrast, 8,13 Fourier Ptychography, 10 4D light field capture, 8,9 and 3D phase and amplitude imaging. 14 To implement DPC, we capture two images: one with half of the brightfield LEDs on, and one with the other half.…”

“…[8][9][10][11][12][13][14] The hardware involves replacing the microscope's illumination unit with an LED array placed at some distance away from the sample (see Fig. 1).…”

Motion deblurring with temporally coded illumination in an LED array microscope

“…In the recently introduced LED array microscope, the illumination unit of a commercial microscope is replaced by a programmable LED array, creating a powerful computational imaging platform. Spatially coding the illumination has lead to a variety of techniques, including digital refocusing [2], real-time multicontrast [3], 3D phase imaging [4,5], and resolution beyond the objective's diffraction limit via Fourier Ptychography [6,7]. All of these capabilities use the same hardware but different illumination pattern schemes.…”