wonchan Lee

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Małgorzata Kujawińska

Warsaw University of Technology

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Renjie Zhou

Massachusetts Institute of Technology (MIT)

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University of Illinois at Urbana-Champaign

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Single-exposure quantitative phase imaging in color-coded LED microscopy (Conference Presentation)

We demonstrate single-shot quantitative phase imaging (QPI) in a platform of color-coded LED micr... more We demonstrate single-shot quantitative phase imaging (QPI) in a platform of color-coded LED microscopy (cLEDscope). The light source in a conventional microscope is replaced by a circular LED pattern that is trisected into subregions with equal area, assigned to red, green, and blue colors. Image acquisition with a color image sensor and subsequent computation based on weak object transfer functions allow for the QPI of a transparent specimen. We also provide a correction method for color-leakage, which may be encountered in implementing our method with consumer-grade LEDs and image sensors. Most commercially available LEDs and image sensors do not provide spectrally isolated emissions and pixel responses, generating significant error in phase estimation in our method. We describe the correction scheme for this color-leakage issue, and demonstrate improved phase measurement accuracy. The computational model and single-exposure QPI capability of our method are presented by showing images of calibrated phase samples and cellular specimens.

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Smartphone-based multi-contrast microscope using color-multiplexed illumination

Scientific Reports, 2017

We present a portable multi-contrast microscope capable of producing bright-field, dark-field, an... more We present a portable multi-contrast microscope capable of producing bright-field, dark-field, and differential phase contrast images of thin biological specimens on a smartphone platform. The microscopy method is based on an imaging scheme termed “color-coded light-emitting-diode (LED) microscopy (cLEDscope),” in which a specimen is illuminated with a color-coded LED array and light transmitted through the specimen is recorded by a color image sensor. Decomposition of the image into red, green, and blue colors and subsequent computation enable multi-contrast imaging in a single shot. In order to transform a smartphone into a multi-contrast imaging device, we developed an add-on module composed of a patterned color micro-LED array, specimen stage, and miniature objective. Simple installation of this module onto a smartphone enables multi-contrast imaging of transparent specimens. In addition, an Android-based app was implemented to acquire an image, perform the associated computatio...

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Single-exposure quantitative phase imaging in color-coded LED microscopy

Optics express, Jan 3, 2017

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Color-coded LED microscopy for quantitative phase imaging: Implementation and application to sperm motility analysis

Methods (San Diego, Calif.), Jan 22, 2017

Color-coded light-emitting diode (LED) microscopy (cLEDscope) is a novel computational microscopy... more Color-coded light-emitting diode (LED) microscopy (cLEDscope) is a novel computational microscopy technique capable of multi-contrast and quantitative phase imaging of biological specimens using color-multiplexed illumination. Using specially designed LED patterns, it is capable of recording multiple differential phase contrast (DPC) images in a single exposure and employs a computational algorithm to retrieve the phase distribution of the specimens. Herein, we describe the detailed procedures in the cLEDscope implementation for quantitative phase imaging. Several notable features and caveats in the cLEDscope setup and image processing are also outlined. The imaging model is derived for our specific configuration, and the associated phase-retrieval algorithms are presented on the basis of a weak-object transfer function. As an illustrative application of the quantitative cLEDscope, we demonstrate its utility as a sperm-motility analyzer by exploiting its real-time quantitative imagi...

Single-exposure quantitative phase imaging in color-coded LED microscopy (Conference Presentation)

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Smartphone-based multi-contrast microscope using color-multiplexed illumination

Scientific Reports, 2017

Download

Single-exposure quantitative phase imaging in color-coded LED microscopy

Optics express, Jan 3, 2017

Download

Color-coded LED microscopy for quantitative phase imaging: Implementation and application to sperm motility analysis

Methods (San Diego, Calif.), Jan 22, 2017

wonchan Lee

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