apm_fracture_df¶
Description: Reads in a binary fracture image stack and calculates the fractal dimension (Df) along either the X and/or Z axis.
For usage information run: apm_fracture_df h

class
apmapflow.scripts.apm_fracture_df.
FractureSlice
(slice_data)[source]¶ Stores the fractal information for a single slice

Fractal
¶ alias of
fractal

bifurcation_frac
¶ calculates fractional bifurcation

slice_data
¶ returns the slice data

zero_ap_frac
¶ calculates fractional bifurcation


apmapflow.scripts.apm_fracture_df.
calculate_df
(line_trace)[source]¶ Code initially written by Charles Alexander in 2013 Modified by Dustin Crandall in 2015 Rewritten into Python by Matt Stadelman 11/15/2016
Based on the methodology presented in Dougan, Addison & McKenzie’s 2000 paper “Fractal Analysis of Fracture: A Comparison of Methods” in Mechanics Research Communications.
The Hurst exponent is defined as equal to 2  the fractal dimension of a fracture profile
H = 2  Df Df = 2  H
The method calculates the Hurst Exponent of a fracture profile using the “Variable Bandwidth Method”, wherein a window of size ‘s’ is moved along the fracture profile and the standard deviation of the displacement of the profile at the ends of the window is calculated
Formulation:
Ns sigma_s = [(1/Ns)*SUM((Profile_height(i)  Profile_height(i+s))^2)]^1/2 i=1
where sigma_s = incremental standard deviation N = number of data points Profile_height(x) = height of profile at x
H is determined as the slope of the plot of log10(sigma_s) against log10(s)
returns a range of standard deviations for each bandwidth useds

apmapflow.scripts.apm_fracture_df.
df_best_fit
(df_data)[source]¶ With large window sizes the realtionship between the log10(window size) and the log10(standard deviation of change in height) does not appear to follow a linear trend, which we should see to calculate the Hurst Exponent
This function is designed to find where the R^2 value of a linear fit to the data is minimum

apmapflow.scripts.apm_fracture_df.
find_profiles
(fracture_slice)[source]¶ Takes in a 2D data slice and generates line traces for JRC and Df analysis.
Returns a dictionary of the top, bottom and midsurface traces as well as the fraction of bifurcations and zero aperture zones.

apmapflow.scripts.apm_fracture_df.
main
()[source]¶ Driver program to load an image and process it to output hurst exponents