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In this paper, the header ratio is defined as the ratio between the SEG Y header data volume and the SEG Y file size, a formula describing the relationship between the header ratio, the compression ratio of SEG Y header data and the compression ratio of the SEG Y file is derived. It is discovered from the formula that the theoretical limit of the SEG Y file compression ratio is the quotient of the SEG Y header data compression ratio divided by the header ratio, therefore, it is necessary to compress the header data efficiently in order to get a high compression of the SEG Y file. Furthermore, the statistical properties of the SEG Y reel header data and trace header data are analyzed. An efficient lossless compression method for SEG Y header data, known as Header Identification Data Lossless Prediction Coding (HIDLPC) method, is proposed based on the statistical properties of the SEG Y header data. Experimental results show that the lossless compression ratio by using HIDLPC to compress SEG Y header data locates between 30 and 1000, much higher than the corresponding compression ratios by using Winzip and WinRAR. |
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