随机调制信号下的模拟ppm，结合PCA的尺度不变特征变换(SIFT)算法，包括主成分分析、因子分析、贝叶斯分析。- Random ppm modulated analog signal under Combined with PCA scale invariant feature transform (SIFT) algorithm, Including principal component analysis, factor analysis, Bayesian analysis.

There is a well attenuation curve as input to calculate its seismic waves, Combined with PCA scale invariant feature transform (SIFT) algorithm, Least-squares regression analysis algorithm.