Data compression for seismic data using trigonometric transformation

摘要

PCT No. PCT/GB96/02885 Sec. 371 Date Aug. 13, 1998 Sec. 102(e) Date Aug. 13, 1998 PCT Filed Nov. 22, 1996 PCT Pub. No. WO97/21115 PCT Pub. Date Jun. 12, 1997The method includes the steps of applying a local spatial trigonometric transformation to seismic data to generate transformed data and compressing the transformed data. Compression may be achieved by retaining a selected part of the transformed data at reduced accuracy. The selected part may be a high frequency part of the transformed data. A window function is chosen so that the transformations are applied over a central window and overlap with the adjoining windows. Suitable transformations for use with the method include a local cosine transformation, a discrete cosine transformation of type IV, a local sine transformation and a Fourier transformation. For example, a HF part of the transformed data is retained at reduced accuracy. The transformed data is compressed by a coarser re-quantization of the transformed data. A temporal transformation is applied to the seismic data, that is local and of the trigonometric type. A window function is selected so that the transformations are applied over a central window and an overlap with adjoining windows. The transformations preserve the number of samples. A reduced redundancy in the transformed data is used to further reduce the compressed data.