| 摘要 |
1,112,121. Geophysical prospecting. CONDUCTRON CORPORATION. 23 April, 1965 [27 April, 1964; 24 June, 1964], No. 17159/65. Heading H4D. [Also in Division G2] Geophysical data is processed by recording the data on a transparency and optically converting the transparency to its Fourier transform for analysis or further processing. For removing undesired data from a seismic section comprising a plurality of parallel, variable-area or variable-density traces and corrected for static and normal moveout errors, the section is recorded as a transparency 36 which is illuminated by collimated light from a heliumneon laser 20, 21, 22. The Fourier transform of the transparency (which acts as a diffraction grating) is formed at 44 by lenses 38 and 42 and comprises points of light whose distance from the optic axis is dependent on the spatial frequency of seismic " events " in the traces of the transparency. Alignments of " events " on the traces give alignments of points of light in the transform, the latter alignments appearing at 90 degrees (measured round the optic axis) to the former. An adjustable filter mask 46 blocks undesired frequency components or undesired alignments, e.g. those from multiple reflections of seismic energy, which are oriented differently from desired primary alignments. Lens 42 provides a magnification of the Fourier image to make positioning of mask 46 less critical. The filtered transform is subjected to a further Fourier transformation by a lens 48 and the reconstituted image of the processed transparency is recorded at 54. The reconstituted image at 54 may be observed to determine the optimum adjustment of mask 46 or to provide a basis for designing field recording procedures and other data processing operations for optimum removal of undesired data. Instead of masking off Fourier transform components, the filter 46 may alter the relative phasing of different components by some fraction of a light wavelength. Field recording procedures for obtaining the seismic section are described. |
