Method for compression of high resolution seismic data

• US 5,757,852 A
• Filed: 01/24/1997
• Issued: 05/26/1998
• Est. Priority Date: 01/24/1997
• Status: Expired due to Term

• Current Assignee: WesternGeco LLC
• Original Assignee: Western Atlas International Incorporated (Northrop Grumman Corporation)
• Inventors: Sitton, Gary A., Jericevic, Zeljko
• Primary Examiner(s): Ghebretinsae, Temesghen
• Application Number:
  US08/787,310
• Time in Patent Office: 487 Days
• Field of Search: 375/240, 375/241, 370/477, 348/384, 358/426, 382/232, 382/244, 382/250, 381/2.1, 364/715.02
• US Class Current: 375/240
• CPC Class Codes: H03M 7/3013 Non-linear modulators

Abstract

A method of compressing digital signals for transmission and/or storage. The method includes lossy compressing the digital signal to generate a lossy compressed signal. The compressed signal is decompressed locally to generate a local lossy decompressed signal. An error signal is calculated as the difference between the original digital signal and the local lossy decompressed signal. The power in the original digital signal and in the error signal is determined. A minimum resolution for quantizing the error signal is determined from a ratio of the power of the original signal with respect to power of the error signal. The error signals is lossy compressed by quantizing to at least the minimum resolution. Both the compressed digital signal and the compressed error signal are transmitted and/or stored. The lossy compressed error signal and the lossy compressed signal are recovered from storage or transmission. The lossy compressed signal and the lossy compressed error signal are decompressed, and the decompressed lossy compressed original signal and the decompressed lossy compressed error signal are summed to generate the recovered original digital signal.

Claims

1. A method of compressing signals for transmission and storage, comprising:

lossy compressing an original signal to generate a lossy compressed signal;

decompressing said lossy compressed signal to generate a local lossy decompressed signal;

calculating an error signal be determining a difference between said original signal and said local lossy decompressed signal;

determining an autocorrelation characteristic of said original signal and of said error signal;

determining a minimum resolution for quantizing said error signal from a ratio of said autocorrelation characteristic of said original signal with respect to said autocorrelation characteristic of said error signal;

lossy compressing said error signal, said step of lossy compressing said error signal including quantizing to at least said minimum resolution;

recovering said lossy compressed error signal and said lossy compressed signal;

decompressing said lossy compressed signal and said lossy compressed error signal; and

summing said decompressed lossy compressed signal and said decompressed lossy compressed error signal to generate a recovered original signal.

2. The method as defined in claim 1 wherein said step of lossy compression of said original signals comprises blocked discrete cosine transforming.

3. The method as defined in claim 1 wherein said step of lossy compression of said original signals comprises discrete wavelet transforming.

4. The method as defined in claim 1 wherein said step of lossy compression of said original signals comprises quantization.

5. The method as defined in claim 1 wherein said step of lossy compression of said error signal comprises quantizing to a fixed number of bits.

6. The method as defined in claim 1 wherein said step of lossy compression of said error signal comprises quantizing to a fixed number of bits in combination with fixed entropy encoding.

7. The method as defined in claim 1 wherein said autocorrelation characteristic comprises power.

8. The method as defined in claim 1 wherein said autocorrelation characteristic comprises amplitude.

9. A method of compressing signals for transmission and storage, comprising:

lossy compressing an original signal to generate a lossy compressed signal;

decompressing said lossy compressed signal to generate a local lossy decompressed signal;

calculating an error signal be determining a difference between said original signal and said local lossy decompressed signal;

lossy compressing said error signal;

recovering said lossy compressed error signal and said lossy compressed signal;

decompressing said lossy compressed signal and said lossy compressed error signal; and

summing said decompressed lossy compressed signal and said decompressed lossy compressed error signal to generate a recovered original signal.

10. The method as defined in claim 9 further comprising:

determining an autocorrelation characteristic of said original signal and of said error signal;

determining a minimum resolution for quantizing said error signal from a ratio of said autocorrelation characteristic of said original signal with respect to said autocorrelation characteristic of said error signal; and

wherein said step of lossy compressing said error signal includes quantizing to at least said minimum resolution.

11. The method as defined in claim 10 wherein said step of lossy compression of said error signal comprises quantizing to a fixed number of bits.

12. The method as defined in claim 10 wherein said step of lossy compression of said error signal comprises quantizing to a fixed number of bits in combination with fixed entropy encoding.

13. The method as defined in claim 9 wherein said step of lossy compression of said original signals comprises blocked discrete cosine transforming.

14. The method as defined in claim 9 wherein said step of lossy compression of said original signals comprises discrete wavelet transforming.

15. The method as defined in claim 9 wherein said step of lossy compression of said original signals comprises quantization.