The standard of care for clinical assessment of burn severity and extent lacks a quantitative measurement. In this work, spatial frequency domain imaging (SFDI) was used to measure 48 thermal burns of graded severity (superficial partial, deep partial, and full thickness) in a porcine model. Functional (total hemoglobin and tissue oxygen saturation) and structural parameters (tissue scattering) derived from the SFDI measurements were monitored over 72 h for each burn type and compared to gold standard histological measurements of burn depth. Tissue oxygen saturation (stO2) and total hemoglobin (ctHbT) differentiated superficial partial thickness burns from more severe burn types after 2 and 72 h, respectively (p<0.01), but were unable to differentiate deep partial from full thickness wounds in the first 72 h. Tissue scattering parameters separated superficial burns from all burn types immediately after injury (p<0.01), and separated all three burn types from each other after 24 h (p<0.01). Tissue scattering parameters also showed a strong negative correlation to histological burn depth as measured by vimentin immunostain (r2>0.89). These results show promise for the use of SFDI-derived tissue scattering as a correlation to burn depth and the potential to assess burn depth via a combination of SFDI functional and structural parameters.
The ability to quantitatively determine tissue fluorescence is of interest for the purpose of better understanding the details of photodynamic therapy of skin cancer. In particular, we are interested in quantifying protoporphyrin IX (PpIX) in vivo. We present a method of correcting fluorescence for effects of native tissue absorption and scattering properties in a spatially resolved manner that preserves the resolution of the fluorescence imaging system, based off a homogeneous representation of tissue. Validation was performed using a series of liquid turbid phantoms having varying concentrations of absorber, scatterer, and fluorophore (PpIX). Through the quantification of tissue optical properties via spatial frequency domain imaging, an empirical model based on Monte Carlo simulations was deployed to successfully decouple the effects of absorption and scattering from fluorescence. From this we were able to deduce the concentration of the PpIX to within 0.2 μg/ml of the known concentration. This method was subsequently applied to the determination of PpIX concentration from in vivo normal skin where the model-based correction determined a concentration of 1.6 μg/ml, which is in agreement with literature.
The Navy recently began investing in the design of mission-specific payloads for the Small Tactical Unmanned Aircraft
System (STUAS). STUAS is a Tier II size UAS with a roughly 35 pound mission payload and a gimbaled general-purpose
electro optical/infrared (EO/IR) system. The EO/IR system is likely composed of a video camera in the visible,
a mid-wave infrared (MWIR) and/or a long-wave infrared (LWIR) for night operations, and an infrared marker and laser
range finder.
Advanced Coherent Technologies, LLC (ACT), in a series of SBIR efforts, has developed a modular, multi-channel
imaging system for deployment on airborne and UAV platforms. ACT's system, called EYE5, demonstrates how an
EO/IR system combined with an on-board, real-time processor can be tailored for specific applications to produce real-time
actionable data. The EYE5 sensor head and modular real-time processor descriptions are presented in this work.
Examples of the system's abilities in various Navy-relevant applications are reviewed.
KEYWORDS: Image processing, Cameras, Imaging systems, Ocean optics, Detection and tracking algorithms, Oceanography, Global Positioning System, Signal to noise ratio, Electro optical systems, Algorithm development
This work presents an electro-optical multispectral capability that detects and monitors marine mammals. It is a
continuance of Whale Search Radar SBIR program funded by PMA-264 through NAVAIR. A lightweight, multispectral,
turreted imaging system is designed for airborne and ship based platforms to detect and monitor marine mammals. The
system tests were conducted over the Humpback whale breeding and calving area in Maui, Hawaii. The results of the
tests and the system description are presented. The development of an automatic whale detection algorithm is discussed
as well as methodology used to turn raw survey data into quantifiable data products.
Advanced Coherent Technologies, LLC has demonstrated the use of multi-channel imaging systems in a variety of
applications. These systems are composed of multiple cameras or 'channels', each of which can be coupled with spectral
filters, polarization analyzers, or unique optics (e.g. for field of view (FOV) or aperture adjustments). The channel
content is designed specifically for the extraction of information and/or the detection of targets. Airborne data collects
have been made over forest and maritime environments for the detection of various targets. The results of these collects
are discussed and analyzed. Of particular concern is how channel content is chosen in each environment and for each
target.
This paper will present the development of a new driver board for the Texas Instruments DiscoveryTM 3000
Micromirror Device (DMD) chipset being offered by Texas Instruments. A requirement of our current research is to
have a real-time digital interface to a reflective spatial light modulator to project patterns based upon images obtained
via a camera system. As a result, we developed the DVimageTM spatial light modulator driver board based upon the
Texas Instruments DiscoveryTM 3000 chipset. The DVimageTM can be run from any computer through the standard
DVI port, can display 8-bit grayscale at 60Hz in real-time and can store 4600 full resolution 1-bit images on the board
and display them at a maximum frame rate of 16,300 fps. The board also has programmable sync pins to trigger other
systems (e.g. light sources, cameras). An SDK and software examples have been developed to allow for integration into
custom applications. This paper will describe the general hardware architecture and software tools along with example
applications for this spatial light modulator system.
Principal component analysis (PCA) in the wavelet domain provides powerful new features for the non-invasive detection of cervical intraepithelial neoplasia (CIN) using fluorescence imaging spectroscopy. These features are known as principal wavelet components (PWCs). The multiscale structure of the fluorescence spectrum for each pixel of the hyperspectral data cube is extracted using the continuous wavelet transform. PCA is then used to compress and denoise the wavelet representation for presentation to a feed- forward neural network for tissue classification. Using PWC features as inputs to a 5-class NN resulted in average correct classification rates of 95% over five cervical tissue classes corresponding to low-grade dysplasia, squamous, columnar, metaplasia plus a fifth class for other unspecified tissue types, blood and mucus. A 2-class NN was also trained to discriminate between CIN1 and normal tissue with sensitivity and specificity of 98% and 99%, respectively. All performance assessments were based on test data from a set of patients not seen during NN training. Trained neural classifiers were used to `compress' and transform 3D hyperspectral data cubes into 2D color-coded images that accurately mapped the spatial distribution of both normal and dysplastic tissue over the surface of the entire cervix.
Laser induced breakdown spectroscopy (LIBS) is being used to detect heavy metal concentrations in soils. The overall goal of this effort is to develop a field deployable system that will conduct heavy metal subsurface mapping of the vadose zone using a cone penetrometer deployed fiber optic sensor. This paper presents results on the LIBS analysis of different spiked soil samples with the same chemical matrix, NIST soil samples with variable matrices, a comparison of the performance of the LIBS system with free space delivery of the laser beam versus the performance using an optical fiber probe, and the effect of several system parameters on performance.
The American Society for Testing and Materials (ASTM) has established a radiation standard working group under the auspices of the E13.09 subcommittee on fiber optics, which reports to the E13 committee on molecular spectroscopy. The goal of this working group is to develop and publish standards to qualify fiber optic spectroscopic systems for use in adverse nuclear environments. These goals are in line with the charter of the ASTM organization that is `the development of standards on characteristics and performance of materials, products, systems and services; and the promotion of related knowledge.' Under preliminary efforts to promote the use of fiber optic spectroscopic systems in adverse nuclear environments with an emphasis on nuclear waste storage facilities and nuclear generating stations, two draft standard guides have been prepared to measure ionizing radiation induced spectral changes in optical fibers and cables for use in Broadband systems and remote Raman fiber optic spectroscopic systems.
Optical fiber sensors are finding wider use in all types of applications involving adverse environments, including exposure to radiation. In order to effectively characterize and evaluate the performance of a fiber sensor system for a radiation environment, such as within a nuclear power plant or in a radioactive waste storage/disposal facility, it is beneficial to develop standard test procedures. Science & Engineering Associates (SEA) has developed two such procedures for the American Society for Testing and Materials (ASTM) which address the testing of optical fibers for remote Raman spectroscopic and broadband sensor applications in a steady state radiation environment.
For a number of years, radioactive waste produced from nuclear weapons material processing has been
stored in underground storage tanks (USTs). At some government sites, these tanks were fabricated with both
single and double wall construction with capacities ranging from 500,000 to 1,000,000 gal.[1] These tanks are
typically 6 feet below ground level, 74 feet in diameter, 40 ft. high with a 16 ft.
Solid and hollow waveguides have been employed for spectroscopic and radiometric measurements. Hollow sapphire guides, with a transmission window from 10 - 17 micrometers , are used to detect 20% CO2 in N2. Hollow silica waveguides, with a transmission window from 7 -9 micrometers , are utilized for detecting 100% methane and also for low temperature radiometric measurements from 30 degree(s)C to 150 degree(s)C. The spectroscopic analysis was accomplished by passing the gas down the interior of the hollow guide for an extended pathlength absorption. The hollow silica guide measured the low temperature region with a minimum resolvable temperature difference of less than 1 degree(s)C.
Hollow waveguides offer applications in remote thermometry and spectroscopy because they transmit infrared radiation and possess chemical and mechanical durability, coupled with high melting points. As in solid dielectric optical fiber, the radiation is propagated by total internal reflection when the refractive index of the cladding is less than that of the air core (n
Spectral attenuation measurements were obtained on some JR transmitting waveguides to
evaluate their applicability for remote sensing and laser power delivery. Since there is such a wide
variety of applications for fiber optics in these areas, it is important to evaluate materials with various
physical and optical properties. Three categories of waveguides where analyzed: glass, crystalline, and
hollow tubes. A fluoroaluminate glass optical fiber was fabricated and the attenuation was considerably
higher (102103 times higher) than the more common ZBLAN fluoride optical fibers. A Te-Se-Br glass
optical fiber was evaluated and it exhibited an extended JR edge to approximately 14 rim. Attenuation
measurements were conducted on single crystal sapphire, silicon, KRS-13, and KBr core/KC1 clad optical
fibers. The spectral characteristics of alumina, silica glass, and mullite hollow waveguides were also
determined, and all measurements were obtained using a Fourier Transform Infrared Spectrometer.
New IR glasses transmitting from 1 to 20 im and having low loss potentiality in the 8- 12 pm region have
been obtained in the Te-Br-Se and Te-I-Se systems. Single index fibers have been drawn from rods and the
attenuation measuredin normal atmospheric conditions. The influence ofthe band gap absorption mechanism
appears to be very critical as well as the addition ofelements such as Bi which seems to improve the mechnical
properties.
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