Color-coded LED microscopy for multi-contrast and quantitative phase-gradient imaging.

Donghak Lee,Suho Ryu,Daeseong Jung,Chulmin Joo,Uihan Kim

doi:10.1364/boe.6.004912

Abstract

We present a multi-contrast microscope based on color-coded illumination and computation. A programmable three-color light-emitting diode (LED) array illuminates a specimen, in which each color corresponds to a different illumination angle. A single color image sensor records light transmitted through the specimen, and images at each color channel are then separated and utilized to obtain bright-field, dark-field, and differential phase contrast (DPC) images simultaneously. Quantitative phase imaging is also achieved based on DPC images acquired with two different LED illumination patterns. The multi-contrast and quantitative phase imaging capabilities of our method are demonstrated by presenting images of various transparent biological samples.

Highlights

Optical microscopy is a ubiquitous tool in diverse disciplines, providing detailed visualization of materials and biological specimens [1]
A color image sensor (IOI Flare 2M-180CL, Ontario, Canada) was installed at the image port of the microscope, and the image acquisition and computation of BF, DF and differential phase contrast (DPC) images were performed with a software written in LabVIEW (National Instruments Co., Austin, TX, USA)
Single-shot, multi-contrast imaging capability of the cLEDscope was first assessed by imaging various translucent specimens, such as onion cells and fish scales

Summary

Methods

“Microscopy refocusing and dark-field imaging by using a simple LED array,” Opt. Lett. “3D differential phase-contrast microscopy with computational illumination using an LED array,” Opt. Lett. “Quantitative differential phase contrast imaging in an LED array microscope,” Opt. Express 23(9), 11394–11403 (2015). “Differential phase contrast in scanning optical microscopy,” J. “Differential phase-contrast microscope with a split detector for the readout system of a multilayered optical memory,” Appl. “Quantitative phase imaging using a partitioned detection aperture,” Opt. Lett. Wilson, “Improved imaging of phase gradients in scanning optical microscopy,” J. J. Sheppard, “Quantitative phase-gradient imaging at high resolution with asymmetric illumination-based differential phase contrast,” Opt. Lett. “3D intensity and phase imaging from light field measurements in an LED array microscope,” Optica 2(2), 104–111 (2015). Waller, “Multiplexed coded illumination for Fourier Ptychography with an LED array microscope,” Biomed.

Introduction

Results

Single-shot multi-contrast imaging

Phase measurement accuracy

Effect of specimen dispersion on phase measurement

Discussion and conclusion