Scientific and Technical Aerospace Reports Volume 38 July 28, 2000

20000063388 College of William and Mary, Dept. of Computer Science, Williamsburg, VA USA
Fidelity Analysis of Sampled Imaging Systems
Park, Stephen K., College of William and Mary, USA; Rahman, Zia-ur, College of William and Mary, USA; Optical Engineering;
May 1999; Volume 38, No. 5, pp. 786-800; In English; Sponsored in part by Battelle
Contract(s)/Grant(s): NCC1-258; DAAL03-91-C-0034; Copyright; Avail: Issuing Activity
Many modeling, simulation and performance analysis studies of sampled imaging systems are inherently incomplete because
they are conditioned on a discrete-input, discrete-output model that only accounts for blurring during image acquisition and additive
noise. For those sampled imaging systems where the effects of digital image acquisition, digital filtering and reconstruction
are significant, the modeling, simulation and performance analysis should be based on a more comprehensive continuous-input,
discrete-processing, continuous-output end-to-end model. This more comprehensive model should properly account for the lowpass
filtering effects of image acquisition prior to sampling, the potentially important noiselike effects of the aliasing caused by
sampling, additive noise due to device electronics and quantization, the generally high-boost filtering effects of digital processing,
and the low-pass filtering effects of image reconstruction. This model should not, however, be so complex as to preclude significant
mathematical analysis, particularly the mean-square (fidelity) type of analysis so common in linear system theory. We demonstrate
that, although the mathematics of such a model is more complex, the increase in complexity is not so great as to prevent
a complete fidelity-metric analysis at both the component level and at the end-to-end system level: that is, computable meansquare-based
fidelity metrics are developed by which both component-level and system-level performance can be quantified. In
addition, we demonstrate that system performance can be assessed qualitatively by visualizing the output image as the sum of three
component images, each of which relates to a corresponding fidelity metric. The cascaded, or filtered, component accounts for
the end-to-end system filtering of image acquisition, digital processing, and image reconstruction; the random noise component
accounts for additive random noise, modulated by digital processing and image reconstruction filtering; and the aliased noise component
accounts for the frequency folding effect of sampling, modulated by digital processing and image reconstruction filtering.
Author
Imaging Techniques; Mathematical Models; Sampling; Mean Square Values; Linear Systems; End-to-End Data Systems
20000063390 ViA, Inc., Northfield, MN USA
Wrist Interactive Device for Wearable PC Monthly Report, 1-31 Mar. 2000
Dini, Paolo; Apr. 07, 2000; 8p; In English
Contract(s)/Grant(s): N00421-97-C-1293
Report No.(s): AD-A377319; No Copyright; Avail: CASI; A02, Hardcopy; A01, Microfiche
No Abstract Available.
DTIC
Applications Programs (Computers); Software Development Tools; Software Engineering
20000063508 Army Research Lab., Cleveland, OH USA
The NPARC Alliance: A Science and Technology/Test and Evaluation Partnership Example
Acosta, Waldo A., Army Research Lab., USA; Matty, Jere J., Arnold Engineering Development Center, USA; May 2000; 12p;
In English; Test and Evaluation and Science and Technology: Forging Partnerships for the Future of Aerospace, 12-15 Oct. 1999,
Tullahoma, TN, USA; Sponsored by International Test and Evaluation Association, Unknown; Original contains color illustrations
Contract(s)/Grant(s): RTOP 714-04-50; DA Proj. 1L1-62211-A-47-A
Report No.(s): NASA/TM-2000-210064; E-12291; NAS 1.15:210064; ARL-TR-2112; No Copyright; Avail: CASI; A03, Hardcopy;
A01, Microfiche
The NPARC Alliance is a partnership between NASA’s Glenn Research Center, the Air Force’s Arnold Engineering Development
Center, and industry. We have been working together since the early 90s to produce flow solvers for use in advanced aerospace
applications. This flow simulation system (WIND) is continuously being improved and validated by the NPARC Alliance
to address the U.S. aerospace community’s requirements for an efficient general-purpose tool. The Alliance provides support to
all user organizations, serves as the national focal point for NPARC software development/ validation, and ensures that these
efforts remain customer focused by actively seeking feedback from the user community. This paper provides an overview of the
capabilities of the NPARC Alliance simulation system, a description of the development process, and discusses the history and
progress of the Alliance to date.
Author
Aerospace Engineering; Organizations; Research and Development; Software Engineering
158