frequency analysis for plane-wave destructors

In this example, we use sigclear platform to do the experiment related to Figure 2 in the paper Omnidirectional plane-wave destruction. It compares the frequency responses of LPWD and OPWD operators on three different dipping angles. sigclear platform can handle this experiment simply with only two Processes: one for the frequency analysis of all cases, and another one generate the QC figure.

Download Experiment

1. frequency responses analysis

from experiment import *

Process('freq', None,
	'''
    sgcreate nx=603 vectors=lpwd
      lpwd.type=cfloat lpwd.ns=201 lpwd.ds=0.005 lpwd.s0=-0.5 
    | sgfieldmath ig:i="ix/201" index="ix%201" theta:i="20+30*ig" 
      w2:f="-0.5+0.005*index" slope:f="2*PI*tan(PI*theta/180)" 
      p1:f="2*PI*sin(PI*theta/180)" p2:f="2*PI*cos(PI*theta/180)" 
      lpwd="1-exp(-I*2*PI*w2)*exp(-I*slope*lpwd.time)"
      opwd:X="1-exp(-I*lpwd.time*p1)*exp(-I*p2*w2)" 
    | sgsort key=group,theta,w2
	''')

In this process, it
1. creates a 2D analysis space of 603X201 frequencies;
2. split the 2D frequency space into 3 samll ones of dimension 201X201, with each for a dipping angle;
3. creates two vectors lpwd and opwd for two PWD operators, and calculates the frequency responses for the two PWD operators.
2. generate the QC figure

Figure('./freq.png',
	'''
	sgplotps left.label=w1 
	''')

The final ouput figures are as follows



Even the code for figure generating is simple, and no information for the plotting features is provided, the output figure is well organized for scientific requirements.

It is easy to generate the QC figures in different styles.

References:

1. Chen, Z., Fomel, S., & Lu, W. (2013). Omnidirectional plane-wave destruction. Geophysics, 78(5), V171-V179.