在高保真条件下同时提高信噪比和分辨率问题的研究──噪声对分辨率的影响
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摘要
本文论述了噪声对分辨率的影响、噪声是提高分辨率的最大障碍．主要表现在以下两个方面：首先，噪声本身降低分辨率，其次，由于反褶积降低信噪比。因此，噪声的存在限制了分辨率的提高。在噪声存在的情况下，地震记录的分辨率取决于有效频宽，以及其高低截频点。一般地说，地震记录的有效频带越宽，信号的高低频越丰富，地震记录的分辨率就越高。本文还在理论上证明了，当信号与噪声在频率域重合时，对线性时不变滤波而言，提高信噪比和提高分辨率是一对矛盾的要求。线性时不变滤波不能提高单一频率分量信噪比。因此，也就不能展宽有效颇显。另一方面，若原始记录的信噪比很低，一味地通过反褶积提高分辨率是没有意义的。
This paper discusses the influence of noise on resolution. Noise is the biggest entanglement of enhancing resolution, its main expressions are on two aspects as follows: first,the noise decreases the resolution; second, the existence of noise limits the enhancement of resolution because of deconvolution reducing SNR. Under the case of existing noise, the resolution of seismic record is decided by effective bandwidth and its high and low cutoff points. Ordinarily, if the effective bandwidth of seismic record is wider, and the high and low frequency of signal is more plentiful.then the resolution of seismic record is higher. This paper also proves in theory that when signal and noise is coincided in frequency domain, it is contradictory for linear time-invariant filter to enhance SNR and resolution simultaneously. The linear time-invariant filter can' t improve SNR of single frequency component. Thus , it can' t widen the effective bandwidth. On the other hand, if the SNR of original record is very low. it is no sense to improve resolution by deconvolution.
This paper discusses the influence of noise on resolution. Noise is the biggest entanglement of enhancing resolution, its main expressions are on two aspects as follows: first,the noise decreases the resolution; second, the existence of noise limits the enhancement of resolution because of deconvolution reducing SNR. Under the case of existing noise, the resolution of seismic record is decided by effective bandwidth and its high and low cutoff points. Ordinarily, if the effective bandwidth of seismic record is wider, and the high and low frequency of signal is more plentiful.then the resolution of seismic record is higher. This paper also proves in theory that when signal and noise is coincided in frequency domain, it is contradictory for linear time-invariant filter to enhance SNR and resolution simultaneously. The linear time-invariant filter can' t improve SNR of single frequency component. Thus , it can' t widen the effective bandwidth. On the other hand, if the SNR of original record is very low. it is no sense to improve resolution by deconvolution.
引文
[1] 黄绪德,《反褶积与地震道反演》,石油工业出版社,1992年,P299。
[2] 邵幼英,一种高分辨率高信噪比处理技术,《石油地球物理勘探》,1990,Vol.25,No.2,P168-176。
[3]俞寿朋等,地震勘探中的分辨率和信噪比问题,《物探科技通报》,1984,Vol.2,No. 2,P25-39。
[4]李庆忠,从信噪比谱分析看滤波及反褶积的效果——频率域信噪比与分辨率的研究,《石油地球物理勘探》, 1986,Vol. 21,No. 6,P575-601。
[5]程乾生.信噪比与分辨率及线性滤波与反滤波,《石油地球物理勘探》,1987,Vo1.22,No. 6,P636-643。
[6]Widess.M. B. Quantifying resolving Power of seismic systems, Geophguics,1982,Vol. 47,P1160-1173。
[2] 邵幼英,一种高分辨率高信噪比处理技术,《石油地球物理勘探》,1990,Vol.25,No.2,P168-176。
[3]俞寿朋等,地震勘探中的分辨率和信噪比问题,《物探科技通报》,1984,Vol.2,No. 2,P25-39。
[4]李庆忠,从信噪比谱分析看滤波及反褶积的效果——频率域信噪比与分辨率的研究,《石油地球物理勘探》, 1986,Vol. 21,No. 6,P575-601。
[5]程乾生.信噪比与分辨率及线性滤波与反滤波,《石油地球物理勘探》,1987,Vo1.22,No. 6,P636-643。
[6]Widess.M. B. Quantifying resolving Power of seismic systems, Geophguics,1982,Vol. 47,P1160-1173。
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