Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


Title: Freeform Illuminator for Computational Microscopy
Programmable illumination control is essential for many computational microscopy techniques. Conventional light source array is often arranged on a fixed grid of a planar surface for providing programmable sample illumination. Here, we report the development of a freeform illuminator that can be arranged at arbitrary 2-dimensional or 3-dimensional (3D) surface structures for computational microscopy. The freeform illuminator can be designed in a small form factor with a dense light source arrangement in 3D. It can be placed closer to the sample for providing angle-varied illumination with higher optical flux and smaller angular increment. With the freeform illuminators, we develop a calibration process using a low-cost Raspberry-Pi image sensor coated with a monolayer of blood cells. By tracking the positional shift of the blood-cell diffraction patterns at 2 distinct regions of the coded sensor, we can infer the 3D positions of the light source elements in a way similar to the stereo vision reconstruction approach. To demonstrate the applications for computational microscopy, we validate the freeform illuminators for Fourier ptychographic microscopy, 3D tomographic imaging, and on-chip microscopy. We also present a longitudinal study by tracking the growth of live bacterial cultures over a large field of view. The reported freeform illuminators and the related calibration process offer flexibilities and extended scope for imaging innovations in computational microscopy.  more » « less
Award ID(s):
2012140
PAR ID:
10438530
Author(s) / Creator(s):
; ; ; ; ; ; ;
Date Published:
Journal Name:
Intelligent Computing
Volume:
2
ISSN:
2771-5892
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ; ; (, SPIE)
    Shen, Xin; Javidi, Bahram; Stern, Adrian (Ed.)
    Digital Lensless Holographic Microscopy (DLHM), or lensless imaging, is an affordable computational imaging approach that reconstructs in-focus images of biological samples directly from their recorded diffraction patterns, eliminating the need for traditional lenses. Commonly, DLHM systems use a spherical wavefront emitted from a point source to directly illuminate a sample placed at any distance between the point source and the camera. One of the main limitations of current DLHM systems is their reduced imaging volume, which is defined by the illumination cone and the sensor size. In this work, we design a freeform-based microlens array to create an array of spherical point sources, enlarging the native sample volume of DLHM system, without sacrificing its spatial resolution 
    more » « less
  2. ; ; ; ; (, Optics Express)
    Dynamic illumination using tunable freeform arrays can enable spatial light distributions of variable size with high uniformity from non-uniform sources through relatively small opposing lateral shifts applied to the freeform components. We present the design, manufacturing, and characterization of a tunable LED-based illuminator using custom freeform Alvarez arrays with commercially available optics to shorten the manufacturing cycle. The optomechanical design and manufacturing of the Alvarez lens arrays and mounting parts are presented in detail. The optical performance of the system is evaluated and compared with simulation results using a custom camera-based test station. Experimental results demonstrate and confirm the dynamic illumination concept with good uniformity. 
    more » « less
  3. ; ; ; (, Optics Express)
    This paper presents a method for evaluating the irradiance of a single freeform surface deviation under extended source illumination. The method takes advantage of a well-known concept, the pinhole image. First, the irradiance of the perturbed freeform surface under point source illumination is computed. Second, a pinhole image of the extended source is obtained by placing a small aperture (pinhole) on the freeform surface. Then, the extended source irradiance pattern change can be quickly calculated by convolving the pinhole image with the perturbed point source irradiance change. The method was experimentally verified, demonstrating the efficacy of the underlying concept. The proposed method alleviates the computational demands during extended source tolerancing, expediting the process. 
    more » « less
  4. ; ; ; ; ; ; ; ; (, Lab on a Chip)
    The recent advent of whole slide imaging (WSI) systems has moved digital pathology closer to diagnostic applications and clinical practices. Integrating WSI with machine learning promises the growth of this field in upcoming years. Here we report the design and implementation of a handheld, colour-multiplexed, and AI-powered ptychographic whole slide scanner for digital pathology applications. This handheld scanner is built using low-cost and off-the-shelf components, including red, green, and blue laser diodes for sample illumination, a modified stage for programmable sample positioning, and a synchronized image sensor pair for data acquisition. We smear a monolayer of goat blood cells on the main sensor for high-resolution lensless coded ptychographic imaging. The synchronized secondary sensor acts as a non-contact encoder for precisely tracking the absolute object position for ptychographic reconstruction. For WSI, we introduce a new phase-contrast-based focus metric for post-acquisition autofocusing of both stained and unstained specimens. We show that the scanner can resolve the 388-nm linewidth on the resolution target and acquire gigapixel images with a 14 mm × 11 mm area in ∼70 seconds. The imaging performance is validated with regular stained pathology slides, unstained thyroid smears, and malaria-infected blood smears. The deep neural network developed in this study further enables high-throughput cytometric analysis using the recovered complex amplitude. The reported do-it-yourself scanner offers a portable solution to transform the high-end WSI system into one that can be made widely available at a low cost. The capability of high-throughput quantitative phase imaging may also find applications in rapid on-site evaluations. 
    more » « less
  5. ; ; ; ; ; ; ; ; (, Communications Biology)
    Abstract Mapping 3D plasma membrane topology in live cells can bring unprecedented insights into cell biology. Widefield-based super-resolution methods such as 3D-structured illumination microscopy (3D-SIM) can achieve twice the axial ( ~ 300 nm) and lateral ( ~ 100 nm) resolution of widefield microscopy in real time in live cells. However, twice-resolution enhancement cannot sufficiently visualize nanoscale fine structures of the plasma membrane. Axial interferometry methods including fluorescence light interference contrast microscopy and its derivatives (e.g., scanning angle interference microscopy) can determine nanoscale axial locations of proteins on and near the plasma membrane. Thus, by combining super-resolution lateral imaging of 2D-SIM with axial interferometry, we developed multi-angle-crossing structured illumination microscopy (MAxSIM) to generate multiple incident angles by fast, optoelectronic creation of diffraction patterns. Axial localization accuracy can be enhanced by placing cells on a bottom glass substrate, locating a custom height-controlled mirror (HCM) at a fixed axial position above the glass substrate, and optimizing the height reconstruction algorithm for noisy experimental data. The HCM also enables imaging of both the apical and basal surfaces of a cell. MAxSIM with HCM offers high-fidelity nanoscale 3D topological mapping of cell plasma membranes with near-real-time ( ~ 0.5 Hz) imaging of live cells and 3D single-molecule tracking. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Text Encoded Conversion
  • XML
  • Save / Share this Record
  • Send to Email