## 1 Introduction  
Passive seismic methods do not require the excitation of explosives, vibroseis, etc. ; they simply require the placement of node geophones according to the active source acquisition line and point spacing, and the data can be collected by continuously receiving ambient noises. Then, by using seismic interferometry (SI), the responses of virtual sources can be retrieved through the correlated responses on the two receivers [1; 2; 3; 4]. The term \"interferometry\" generally refers to the study of interference between signals in order to obtain information through the differences between them. In the field of SI, it is used to study the interference of seismic-related signals. Its basic operation steps are very simple, mainly divided into two steps: the first step is cross-correlation calculation, which can be understood as detecting the travel time difference of waves recorded between two receivers; the second step is stacking--that is, integrating all actual sources. Although the theory of SI is not limited to either body or surface waves [5; 6], extracting surface waves from the cross-correlation of ambient noise is quite robust and has become a mature technology [7]. In contrast, it is much more difficult to extract body waves [8; 9]. However, some studies have also shown its possibility at various scales [10; 11; 12; 13]. Even so, in most SI studies, retrieving surface waves is still one of the major applications. Surface waves with different periods can be used to investigate the earth structure at different depths [14]. Generally speaking, most studies focus on frequencies lower than 1 Hz to provide images of the structure of the crust and upper mantle [15; 16]. However, some studies have proven that structures tens to hundreds of meters underground can be imaged with frequencies higher than 1 Hz, such as by using traffic noise to detect urban underground space [17; 18], which has attracted the attention of more and more engineering seismologists. [PERSON]'s function reconstruction of diffuse wavefield (i.e., waves arrive from all angles with equal strength) observations in an open configuration is the basis for SI with passive data [19]. However, it is not realistic to obtain a pure diffuse wavefield from observations. Non-ideal source distributions such as limited azimuthal distribution or near-source effects [20] can significantly affect the reliability and interpretation of observations due to the violation of the stationarity assumptions required by passive survey methods [21]. In order to improve the accuracy of the dispersion measurement, some studies have begun to consider how to attenuate the influence of noise sources with prominent directivity. [PERSON] [5] proposed a classical spatial autocorrelation method which used the mathematical transformation of a symmetric receiving array (e.g., circle) to eliminate the azimuth factor of the noise source. [PERSON] et al. [22] introduced a novel strategy for imaging dispersion of passive surface waves with an active scheme based on phase-shift measurement, called roadside passive multichannel analysis of surface waves. Scanning processes were implemented along potential azimuthal directions of noise. [PERSON] et al. [23] proposed a cross-correlation-based beamforming average dispersion analysis method which effectively restrained the directionality of noise and reduced the aliasing effect. [PERSON] et al. [24] proposed a multichannel analysis of the passive surface (MAPS) wave method based on long noise sequence cross-correlation to handle the azimuthal effects for directional noise sources. Distinct from the above methods, [PERSON] et al. [25] proposed a new and fast algorithm for accurate noise removal/signal removal based on higher-order statistics (HOS), general cross-validation (GCV), and wavelet hard thresholding (WHT) in synchrosqueezed domains and tested the performance of the proposed algorithm with synthetic and real seismic data. In addition, he indicated that it can also be an effective procedure in ambient noise studies.