Digital mammography is gradually being introduced across all breast screening centres in the UK during 2010. This
provides increased training opportunities using lower resolution, lower cost and more widely available devices, in
addition to the clinical digital mammography workstations. This study examined how experienced breast screening
personnel performed when they examined sets of difficult DICOM two-view screening cases in three conditions: on GE
digital mammography workstations, on a standard LCD monitor (using a DICOM viewer) and an iPhone (running Osirix
software). In each condition they either viewed the full images unaided or were permitted to use the post-processing
manipulations of pan, zoom and window level/width adjustments. For each case they had to report the feature type, rate
their confidence on the presence of abnormality, classify the case and specify case density. Their visual search behaviour
was recorded throughout using a head mounted eye tracker. Additionally aspects of their real life screening performance
and performance on a national self assessment scheme were examined. Data indicate that screening experience plays a
major role in doing well on the self assessment scheme. Task performance was best on the clinical workstation.
However, the data also suggest that a DICOM viewer that runs on a PC or laptop with a standard LCD display allows
viewing digital images in full resolution support impressive cancer detection performance. The iPhone is not ideal for
examining full images due to the amount of scrolling and zooming required. Overall, the results indicate that low cost
devices could be used to provide additional tailored training as long as device resolution and HCI aspects are carefully
considered.
Although existing night vision equipment provides a significant improvement in target detection in low light conditions,
there are several limitations that limit their effectiveness. Focus is a significant problem for night vision equipment due
to the low f-number optics required to obtain sufficient sensitivity as well as the dynamic nature of night vision
applications, which requires frequent focus adjustments. The Georgia Tech Research Institute has developed a prototype
next-generation night vision device called the Improved Night Vision Demonstrator (INVD) in order to address these
shortfalls. This paper will describe the design of the INVD system as well as an analysis of its performance.
The Georgia Tech Research Institute is currently developing a device to demonstrate a hands-free focus technology for
head-mounted night vision sensors. The demonstrator device will integrate a computational imaging technique that
increases depth of field with a digital night vision sensor. The goal of the demonstrator is to serve as a test bed for
evaluating the critical performance/operational parameters necessary for the hands-free focus technology to support
future tactical night vision concepts of operation. This paper will provide an overview of the technology studies and
design analyses that have been performed to date as well as the current state of the demonstrator design.
Numerous papers have been written on the various roles the Wigner distribution function (WDF) can play in optics. The purpose of this paper is to show two applications of the WDF in the analysis, design, and simulation of optical systems. One system provides a vehicle for reducing the computational load in the numerical simulation of the propagation of optical wave fields. The WDF analysis of this system yields insight into methods that might be used in simplifying optical system simulations generally. The second system is intended for the sample-based recording of coherence functions associated with the propagated wave field produced by a three-dimensional, spatially-incoherent object. The WDF analysis, combined with a closely-related ambiguity-function analysis, provides the basic for non-stationary sampling conditions that can be used to determine the minimum number of samples required for the coherence function characterization.
A nonuniform sampling scheme for measuring the mutual intensity of the wavefield produced by an incoherent three-dimensional object is described. The scheme has application to imaging via coherence function measurements and to remote imaging via coherence function transfer. The nonuniform sampling grid is obtained through analysis of an extension of the van Cittert-Zernike relationship appropriate to spatially-limited three-dimensional objects. When compared to the uniform sampling case, a smaller number of measurements is required, and the minimum separation between measurement points is larger.
Analyses of uplink and downlink data from recent free-space optical communications experiments carried out between Table Mountain Facility and the Japanese ETS-VI satellite are presented. Fluctuations in signal power collected by the satellite's laser communication experiment due to atmospheric scintillation and its amelioration using multiple uplink beams are analyzed and compared to experimental data. Downlink data was analyzed to determine the cause of a larger than expected variation in signal strength. In spite of the difficulty in deconvolving atmospheric effects from pointing errors and spacecraft vibration, experimental data clearly indicate significant improvement in signal reception on the uplink with multiple beams, and the need for stable pointing to establish high data rate optical communications.
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