| recent results in automated flaw detection from unreconstructed ct data |
91 |
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| Authors:
k. s. tait; W. G. Heller; J. D. Goldstein; J. V. White
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 | recent results using a new approach to automated flaw detection are presented and compared with standard ct reconstructions. the method is applied to two test disks, one with small isolated holes, the other with large variable density intrusions. successful detections are obtained in both cases. holes of 1 mm diameter are easily detected in the first case, and density variations of 1- 2% are reliably detected in the second case. ... |
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| Automated Flaw Detection using Unreconstructed Computed Tomography Data |
90 |
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| Authors:
J. D. Goldstein; W. G. Heller; J. A. Sivak; J. V. White
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| An algorithm for assessing whether or not any given volume element (voxel) of a test object is flawed or not utilizes x-ray scan data in sinogram form, a reference model for the nominal absorption of the x-ray beams by the test object, and error models for noise and drift in the measured data. By performing detection, a two-valued output process, rather than reconstruction, which requires that the data support a ... |
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| Estimation of Short-Wavelength Gravity on a Dense Grid Using Digital Terrain Elevation Data |
OCT 87 |
41 pages |
| Authors:
J. D. Goldstein; J. V. White; R. P. Commer; W. G. Heller; ANALYTIC SCIENCES CORP READING MA
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 | The precise determination of the gravity field at or near the earth's surface is required for compensating navigation/guidance systems and for testing gravity gradiometers. With conventional gravimeters it is usually impractical to measure the gravity field over an extended area at very short wavelengths(e.g., wavelengths less than 10 km). Since very short-wavelength gravitational perturbations at the surface are caused largely by near-surface mass variations in the local area, and since ... |
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| A Statistical Gravity Model for Northern Texas |
19 NOV 84 |
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| Authors:
J. V. White; ANALYTIC SCIENCES CORP READING MA
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| A statistical gravity field model has been developed for northern Texas, where the Gravity Gradiometer Survey System (GGSS) will be tested. The model is described in this report using both round-earth and flat-earth Attenuated White Noise (AWN) formulations. The model is fitted to all worldwide and local gravity-field information that is applicable to the GGSS test site. In addition, a discrete approximation to the AWN model is described, which can ... |
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| Gravity Gradiometer Survey Data Processing |
30 JUL 84 |
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| Authors:
J. V. White; J. D. Goldstein; ANALYTIC SCIENCES CORP READING MA
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| This Technical Report describes a practical methodology for processing airborne gravity gradiometer survey data to estimate gravity disturbance vectors at the surface of the earth. The methodology also provides an error analysis of the disturbance estimates. Special consideration is given to the data processing and data documentation required for testing of the airborne Gravity Gradiometer Survey System (GGSS). As an example of the data processing methodology, a prototype data template ... |
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| The Weapons Support System Data Smoothing and Spectrum Analysis Program Documentation |
OCT 81 |
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| Authors:
J. V. White; ANALYTIC SCIENCES CORP READING MA
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| This report documents the four programs, GETBELL, AR, FFT, and PLOTFFT, which make up the data smoothing and spectrum analysis software supplied with the Weapons Support System. The programs are designed to run under the VAX/VMS operating system. Information regarding file structures and file- naming conventions is provided in the VAX/VMS System Reference Manuals. Keywords include: Gravity, Gravity Data Evaluation, Weapons Support System, Data Editing, Data Smoothing, Spectrum Analysis, Autoregressive ... |
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