arXiv subjects

Changhuei Yang

Publications and source records attributed to Changhuei Yang.

40 records · Page 3Linked to original sources

arXiv2013

Quantitative phase imaging via Fourier ptychographic microscopy

Fourier ptychographic microscopy (FPM) is a recently developed imaging modality that uses angularly varying illumination to extend a system performance beyond the limit defined by its optical elements. The FPM technique applies a novel phase retrieval procedure to achieve both resolution enhancement and complex image recovery. In this letter, we compare FPM data to both theoretical prediction and phase-shifting digital holography measurement to show that its acquired phase maps are quantitative and artifact-free. We additionally explore the relationship between the achievable spatial and optical thickness resolution offered by a reconstructed FPM phase image. We conclude by demonstrating both enhanced visualization and the collection of otherwise unobservable sample information using FPM quantitative phase.

physics.optics↗

arXiv2013

Characterization of shift-variant pupil aberrations for wide field-of-view microscopy

We describe a simple and robust approach for characterizing the shift-variant pupil aberrations of wide field-of-view microscopy systems. We derive the location-dependent pupil transfer functions by first capturing multiple intensity images at different defocus settings; a generalized pattern search (GPS) algorithm is then applied to recover the complex pupil functions at ~350 different spatial locations over the entire field-of-view. Parameter fitting transforms these pupil functions into accurate 2D aberration maps. We demonstrate shift-variant aberration compensation by using an information-preserving image deconvolution scheme over the entire field-of-view. Such automated shift-variant pupil characterization will facilitate new approaches of aberration correction for future gigapixel imaging platforms.

physics.optics↗

arXiv2012

Large-field-of-view Chip-scale Talbot-grid-based Fluorescence Microscopy

The fluorescence microscope is one of the most important tools in modern clinical diagnosis and biological science. However, its expense, size and limited field-of-view (FOV) are becoming bottlenecks in key applications such as large-scale phenotyping and low-resource-setting diagnostics. Here we report a low-cost, compact chip-scale fluorescence-imaging platform, termed the Fluorescence Talbot Microscopy (FTM), which utilizes the Talbot self-imaging effect to enable efficient fluorescence imaging over a large and directly-scalable FOV. The FTM prototype has a resolution of 1.2 microns and an FOV of 3.9 mm x 3.5 mm. We demonstrate the imaging capability of FTM on fluorescently labeled breast cancer cells (SK-BR-3) and HEK cells expressing green fluorescent protein.

physics.optics↗

arXiv2012

Gigapixel microscopy using a flatbed scanner

Microscopy imaging systems with a very wide field-of-view (FOV) are highly sought in biomedical applications. In this paper, we report a wide FOV microscopy imaging system that uses a low-cost scanner and a closed-circuit-television (CCTV) lens. We show that such an imaging system is capable to capture a 10 mm * 7.5 mm FOV image with 0.77 micron resolution, resulting in 0.54 gigapixels (109 pixels) across the entire image (26400 pixels * 20400 pixels). The resolution and field curve of the proposed system were characterized by imaging a USAF resolution target and a hole-array target. A 1.6 gigapixel microscopy image (0.54 gigapixel with 3 colors) of a pathology slide was acquired by using such a system for application demonstration.

physics.optics↗