U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Search Publications by: David W. Allen (Fed)

Search Title, Abstract, Conference, Citation, Keyword or Author
Displaying 1 - 25 of 168

Hyperspectral dark-field microscopy of human breast lumpectomy samples for tumor margin detection in breast-conserving surgery

May 7, 2024
Author(s)
Jeeseong Hwang, Philip Cheney, Stephen Kanick, Hanh Le, David McClatchy, Helen Zhang, John Lu, Tae Joon Cho, Kimberly Briggman, David W. Allen, Wendy A. Wells, Brian Pogue
Hyperspectral dark-field microscopy (HSDFM) and data cube analysis algorithms demonstrate successful classification of various tissue types, including the detection of carcinoma regions in human post-lumpectomy breast tissues excised during breast

Shifts in belowground processes along a temperate forest edge

April 29, 2024
Author(s)
Rose Abramoff, Jeffrey Warren, Jessica Harris, Sarah Ottinger, Sarah Garvey, Joy Winbourne, Andrew Reinmann, David W. Allen, Lucy Hutyra, Margaret Torn, Melanie Mayes
Forests are increasingly fragmented and as a result most forests in the United States are within 1 km of an edge. Edges change environmental conditions of the forest - especially radiation, roughness, and temperature - that can have consequences for plant

Certification of Standard Reference Material(R) 2196 Axial Resolution Standard for Optical Medical Imaging

February 7, 2023
Author(s)
Jeeseong C. Hwang, Kimberly Briggman, Nikki Rentz, Hyun-Jin Kim, David W. Allen, Lee J. Richter, Sowon Yoon, John Lu
Medical imaging devices and systems must be calibrated to ensure uniformity and reliability of test results. A standard reference material (SRM) or "phantom", as it is known in the medical imaging community, is used to replicate fundamental characteristics

Polydimethylsiloxane tissue-mimicking phantoms with tunable optical properties

July 1, 2022
Author(s)
Aaron Goldfain, Paul Lemaillet, David W. Allen, Kimberly Briggman, Jeeseong C. Hwang
We report on techniques to manufacture and characterize solid tissue-mimicking phantoms of polydimethylsiloxane (PDMS) polymers. Tunability of the absorption (a()) and reduced scattering spectra (s'()) in the wavelength range of 500 nm to 850 nm is

Quantification of urban biogenic carbon fluxes using bottom-up inventory and satellite-based model

January 5, 2022
Author(s)
Joy Winbourne, Hrstiana Stoynova, Ian Smith, Conor Gately, Barry Logan, Jaret Reblin, Andrew Reinmann, David W. Allen, Lucy Hutyra
Cities across the globe are taking the lead on climate mitigation action with ambitious goals to reduce carbon dioxide (CO2) emissions. The implementation of effective mitigation policies will require accurate measurements to guide policy decisions and

Reference data set and variability study for human skin reflectance

June 30, 2019
Author(s)
P. Yvonne Barnes, David W. Allen, Benjamin K. Tsai
The optical properties of human skin have been of interest to researchers for some time. Their interest is based on a need to know for a variety of different applications, which range from spectral imaging for automated or stand-off detection, non-invasive

Exposure Study on the Aging of PTFE and Ceramic Diffusers

February 6, 2019
Author(s)
Benjamin K. Tsai, Catherine C. Cooksey, David W. Allen, Christopher C. White, Walter E. Byrd, Deborah S. Jacobs
This paper describes efforts to quantify the effects of aging in the ultraviolet (UV) on polytetrafluoroethylene (PTFE) and ceramic samples. Long term UV aging may significantly alter the reflectance factor and cause an error in the calibration of

Correction of an adding-doubling inversion algorithm for the measurement of the optical parameters of turbid media

January 1, 2018
Author(s)
Paul Lemaillet, Catherine C. Cooksey, Jeeseong Hwang, Heidrun Wabnitz, Dirk Grosenick, Lin Yang, David W. Allen
We present broadband measurements of the optical properties of tissue-mimicking solid phantoms using a single integrating sphere to measure the hemispherical reflectance and transmittance under a direct illumination at the normal incident angle. These

Approaches for Characterizing Nonlinear Mixtures in Hyperspectral Imagery

June 21, 2017
Author(s)
Robert S. Rand, Ronald G. Resmini, David W. Allen
This study considers a physics-based and a kernel-based approach for characterizing pixels in a scene that may be linear (areal mixed) or nonlinear (intimately mixed). The physics-based method is based on earlier studies that indicate nonlinear mixtures in

Reference Data Set of Human Skin Reflectance

June 7, 2017
Author(s)
Catherine C. Cooksey, David W. Allen, Benjamin K. Tsai
This data set contains 100 reference reflectance spectra of human skin, spanning the wavelength region from 250 nm to 2500 nm. The spectra were acquired with a commercial spectrophotometer and are directly traceable to the national scale for directional

Broadband spectral measurements of diffuse optical properties by an integrating sphere instrument at the National Institute of Standards and Technology

March 30, 2017
Author(s)
Paul Lemaillet, Jeeseong Hwang, Heidrun Wabnitz, Dirk Grosenick, Lin Yang, David W. Allen
Diffuse materials that approximate the optical properties of human tissue are commonly used as phantoms. In order to use the phantoms in a manner that provides consistent results relative to independent measurements, the optical properties need to be tied

Label-free hyperspectral dark-field microscopy towards quantitative scatter imaging

March 27, 2017
Author(s)
Philip Cheney, David McClatchy III, Stephen Kanick, Paul Lemaillet, David W. Allen, Daniel Samarov, Brian Pogue, Jeeseong C. Hwang
A hyperspectral dark-field microscopy technique has been developed for imaging spatially distributed diffuse reflectance spectra from light-scattering samples. In this report, quantitative scatter spectroscopy was demonstrated with a uniform scattering