Active spectral imaging

With the ability to image a scene in tens to hundreds of spectral bands, multispectral and hyperspectral imaging sensors have become powerful tools for remote sensing. However, spectral imaging systems that operate at visible through nearinfrared wavelengths typically rely on solar illumination. This reliance gives rise to a number of limitations, particularly with regard to military applications. Actively illuminating the scene of interest offers a way to address these limitations while providing additional advantages. We have been exploring the benefits of using active illumination with spectral imaging systems for a variety of applications. Our laboratory setup includes multispectral and hyperspectral sensors that are used in conjunction with several laser illumination sources, including a broadband white-light laser. We have applied active spectral imaging to the detection of various types of military targets, such as inert land mines and camouflage paints and fabrics, using a combination of spectral reflectance, fluorescence, and polarization measurements. The sensor systems have been operated under a variety of conditions, both in the laboratory and outdoors, during the day and at night. Laboratory and outdoor tests have shown that using an active illumination source can improve target-detection performance while reducing false-alarm rates for both multispectral and hyperspectral imagers

A case–control analysis of oral contraceptive use and breast cancer subtypes in the African American Breast Cancer Epidemiology and Risk Consortium

Abstract Introduction Recent oral contraceptive (OC) use has been consistently associated with increased risk of breast cancer, but evidence on specific breast cancer subtypes is sparse. Methods We investigated recency and duration of OC use in relation to molecular subtypes of breast cancer in a pooled analysis of data from the African American Breast Cancer Epidemiology and Risk Consortium. The study included 1,848 women with estrogen receptor-positive (ER+) breast cancer, 1,043 with ER-negative (ER-) breast cancer (including 494 triple negative (TN) tumors, which do not have receptors for estrogen, progesterone, and human epidermal growth factor 2), and 10,044 controls. Multivariable polytomous logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for exposure categories relative to never use, controlling for potential confounding variables. Results OC use within the previous 5 years was associated with increased risk of ER+ (OR 1.46, 95% CI 1.18 to 1.81), ER- (OR 1.57, 95% CI 1.22 to 1.43), and TN (OR 1.78, 95% CI 1.25 to 2.53) breast cancer. The risk declined after cessation of use but was apparent for ER+ cancer for 15 to 19 years after cessation and for ER- breast cancer for an even longer interval after cessation. Long duration of use was also associated with increased risk of each subtype, particularly ER-. Conclusions Our results suggest that OC use, particularly recent use of long duration, is associated with an increased risk of ER+, ER-, and TN breast cancer in African American women. Research into mechanisms that explain these findings, especially the association with ER- breast cancer, is needed

Basedow, “Analysis of HYDICE noise characteristics and their impact on subpixel object detection

ABSTRACT A number of organizations are using the data collected by the HYperspectral Digital Imagery Collection Experiment (HYDICE) airborne sensor to demonstrate the utility of hyperspectral imagery (HSI) for a variety of applications. The interpretation and extrapolation of these results can be influenced by the nature and magnitude of any artifacts introduced by the HYDICE sensor. A short study was undertaken which first reviewed the literature for discussions of the sensor' s noise characteristics and then extended those results with additional analyses of HYDICE data. These investigations used unprocessed image data from the onboard Flight Calibration Unit (FCU) lamp and ground scenes taken at three different sensor altitudes and sample integration times. Empirical estimates of the sensor signal-to-noise ratio (SNR) were compared to predictions from a radiometric performance model. The spectral band-to-band correlation structure of the sensor noise was studied. Using an end-to-end system performance model, the impact of various noise sources on subpixel detection was analyzed. The results show that, although a number of sensor artifacts exist, they have little impact on the interpretations of HSI utility derived from analyses of HYDICE data

MEASUREMENTS OF SELF AND AIR BROADENING COEFFICIENTS IN THE NU2 AND NU5 BANDS OF CH3FCH_{3}F,

Author Institution: Department of Physics and Astronomy, Franklin and Marshall CollegeSelf and air broadening coefficients were measured for many lines in this Coriolis perturbed pair of transitions. The J and K dependence of the broadening parameters have been determined. The results of these measurements will be discussed