Communications – electrical: acoustic wave systems and devices – Seismic prospecting – Land-reflection type
Patent
1974-10-03
1980-08-19
Moskowitz, Nelson
Communications, electrical: acoustic wave systems and devices
Seismic prospecting
Land-reflection type
367 49, 367 67, 364421, G01V 128, G01V 136
Patent
active
042187656
ABSTRACT:
This specification discloses an automatic computer-implemented technique for filtering a two-dimensional array of data in the frequency domain. The program converts the array of numbers by Fourier transformation into the real and imaginary part of the frequency domain. In this domain, undesired waves present in the original array can be completely removed by the elimination from the frequency domain of the components of the Fourier-transformed array which fall within (or, if desired, outside of) a convex polygon of arbitrary shape. The system then re-transforms the remaining data back to the time domain, but the undesired components have been filtered. The program can cause the computer to produce a visual reproduction of the filtered array, or it may simply re-format the data of this array on a tape for further computer processing. Accordingly, this invention permits precision spatial filtering of undesired components from the original array. The original array may represent the digitized data from a seismic section, or the amplitude and frequency response of a two-dimensional array of geophones to a steady state alternating seismic wave from a source. A rapid version of large automatic Fourier transformation and re-transformation is included.
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patent: 3705981 (1972-12-01), Harmuth
patent: 3717812 (1973-02-01), Hirsch
Dobrin et al., "Velocity and Frequency Filtering . . . ", 12/65, pp. 1144-1178, Geophysics, vol. 30, #6.
Selzer, "Improving Biomedical Images Quality . . . ", 10/1/68, pp. 1-22, Tech. Report 32-1336, Jet Prop. Lab. at C.I.T.
Lee et al., "Considerations in Optical Filtering", 10/71, 5-1/3PP, Proc. of 2-D Digital Signal Proc. Conference, IEEE.
Hawes et al., "Some Effects of Spatial Filters on Signals", 7/74, Geophysics, vol. 39, #4, pp. 464-498.
Moskowitz Nelson
Standard Oil Company (Indiana)
Stevenson Robert B.
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