相干与方差裂缝检测算法机理研究

An exploration about the mechanism of coherence technique and variance technique for fracture detection

相干法和方差法是裂缝检测中应用得较多的方法,算法公式虽然不复杂,但是对于二代和三代相干算法,却难以明白算法进行裂缝检测的机理。利用数学上排序不等式以及矩阵的知识,分别剖析了第二代相干算法和第三代相干算法的运作机理,并根据算法机理,对第二代相干算法提出了在地下介质变化较缓的情况下的改进建议。此外,分析了方差算法的公式,并对算法做了修改,使算法在垂直时窗加大时,稳定性大大提高,并用实际资料对比了改进前后的方差算法,效果明显。

Coherence technique and variance technique are widely used in fracture detection. Although the formulas of the second and third generation coherence algorithm are not complicated, it is not easy to understand how they work in fracture detection. Using the knowledge of rearrangement inequality and matrix analysis, the second and the third generation coherence algorithms are then deeply analyzed and explained respectively, and according to the analysis of the second generation coherence algorithm, the advice for improving performance in the case that the characteristic of underground medium does not change much is suggested. Furthermore, the variance algorithm is also been analyzed and an improved algorithm is introduced to improve the performance when increasing the vertical time window, and after using practical data to test the original variance algorithm and the improved variance algorithm, the effect prove good.