Imaging through extreme scattering in extended dynamic media.

Critical to navigation, situational awareness, and object identification is the ability to image through turbid water and fog. To date, the longest imaging ranges in such environments rely on active illumination and selection of ballistic photons by means of time gating. Here we show that the imaging range can be extended by using time-gated holography in combination with multi-frame processing. Instead of simply summing the intensity of the frames, we use the complex fields retrieved through digital holographic processing and coherently add the frames. We demonstrate imaging through extended bodies of turbid water and fog at one-way attenuation lengths of 13 and 13.6, respectively. Compared to equivalent traditional time-gated systems, gated holography and coherent processing require 20× less laser illumination power for the same imaging range.

Range performance of the DARPA AWARE wide field-of-view visible imager.

In a prior paper, we described a new imaging architecture that addresses the need for wide field-of-view imaging combined with the resolution required to identify targets at long range. Over the last two years substantive improvements have been made to the system, both in terms of the size, weight, and power of the camera as well as to the optics and data management software. The result is an overall improvement in system performance, which we demonstrate via a maritime target identification experiment.

Characterization of the AWARE 10 two-gigapixel wide-field-of-view visible imager.

System requirements for many military electro-optic and IR camera systems reflect the need for both wide-field-of-view situational awareness as well as high-resolution imaging for target identification. In this work we present a new imaging system architecture designed to perform both functions simultaneously and the AWARE 10 camera as an example at visible wavelengths. We first describe the basic system architecture and user interface followed by a laboratory characterization of the system optical performance. We then describe a field experiment in which the camera was used to identify several maritime targets at varying range. The experimental results indicate that users of the system are able to correctly identify ~10 m targets at between 4 and 6 km with 70% accuracy.

Denoising infrared maritime imagery using tailored dictionaries via modified K-SVD algorithm.

Recent work has shown that tailored overcomplete dictionaries can provide a better image model than standard basis functions for a variety of image processing tasks. Here we propose a modified K-SVD dictionary learning algorithm designed to maintain the advantages of the original approach but with a focus on improved convergence. We then use the learned model to denoise infrared maritime imagery and compare the performance to the original K-SVD algorithm, several overcomplete "fixed" dictionaries, and a standard wavelet denoising algorithm. Results indicate the superiority of overcomplete representations and show that our tailored approach provides similar peak signal-to-noise ratios as the traditional K-SVD at roughly half the computational cost.

Hyperelasticity syndromes.

A review of hyperelasticity syndromes is included. Ehlers-Danlos syndrome, pseudoxanthoma elasticum, cutis laxa and Marfan's syndrome are discussed.

Skin sensitization with the new reagents NOPYE (4-nitro-1-cyclohexyl-3-ethoxy-2-oxo-3-pyrroline) and NOPY-L-phenylalanine.

The aim of this study was to investigate the compound 4-nitro-1-cyclohexyl-3-ethoxy-2-oxo-3-pyrroline (NOPYE) and some related compounds for skin sensitization in guinea pigs, as the first step in a search for more effective skin sensitizers for immunotherapy of cutaneous tumors. In guinea pigs, NOPYE and NOPYE-L-alanine produce far milder delayed hypersensitivity reactions than DNCB. Both NOPYE and DNCB fail to act as adjuvants for skin sensitization to tuberculin purified protein derivative (PPD) and ovalbumin (OV). This suggests an explanation for the lack of effectiveness of DNCB in immunotherapy of metastases: DNCB may be relatively ineffective as an adjuvant for production of specific antitumor immunity. Such adjuvant activity may be essential if the action of the immunotherapeutic reagent is not to be confined to its site of application but is to be effective at the site of distant metastases.

Comparison of different epithelial substrates useful for indirect immunofluorescence testing of sera from patients with active pemphigus.

A positive statistical correlation between intercellular antibody titer and disease severity was found for a group of 6 patients with active pemphigus vulgaris, irrespective of whether indirect IF testing was performed on 5 different epithelial substrates which included guinea pig esophagus, human foreskin, rabbit esophagus, monkey esophagus and monkey lip. In a group of 4 patients with pemphigus foliaceus a positive correlation between disease severity and titer was found only when rabbit esophagus was used for indirect fluorescence testing. In both groups of patients there were individual patients in whom the antibody titer was positive at a time when no disease was present and conversely, there were some patients in whom the antibody titer was negative at a time when extensive disease was present. Because of this inconsistency, the use of antibody titers to monitor disease activity and therapy in individual patients may not be justifiable.

Correlation of antibodies in skin and serum with disease severity in pemphigus.

Direct and indirect immunofluorescence (IF) testing was performed on 63 patients with active or inactive pemphigus in order to determine the reliability of these tests for diagnosis and for monitoring disease severity. Direct IF was positive in 58 of 63 patients with pemphigus. The five patients with negative direct IF had been free of lesions for more than a year. Thus, the direct IF test is a reliable diagnostic procedure that shows positive findings early in the disease. Indirect IF is inferior to direct IF as a diagnostic test because it may be negative in early cases, as observed in four patients. Furthermore, indirect IF, contrary to claims, is not reliable for evaluating the status of the disease. Thus, in patients with lesions and receiving treatment, 41% of the determinations showed a negative titer; whereas in patients free of lesions, 45% of the determinations showed a positive titer. In particular, seven patients without lesions and without treatment for more than a year had a positive titer.