generatedemofile.py

Go to the documentation of this file.

 
r"""
This script generates the `demofile` for [Getting Started](doc/GettingStarted.md).
The demofile simulates a real file exported by the ODiSI Software by Luna Inc.
\author Bertram Richter
\date 2022
"""
 
import datetime
import numpy as np
import os
import scipy.stats
 
def generate_header():
    r"""
    Prints the header file
    """
    file_contents = []
    file_contents
    
    return file_contents
 
def generate_x(start, end, gage_length):
    return np.round(np.arange(start, end, gage_length), 5)
 
def generate_data(x_axis, rng, noise_gain):
    r"""
    Generates the body data.
    """
    y_base = np.zeros(x_axis.shape)
    nan_array = np.full(x_axis.shape, np.nan)
    min_noise_ratio = 0.9
    max_noise_ratio = 1.0
    
    # Peaks: location, height, width
    peaks = [
        (3.20,  500,    .04),
        (3.40,  1200,   .02),
        (3.55,  4050,   .03),
        (3.68,  5000,   .015),
        (3.72,  5500,   .015),
        (3.80,  1200,   .014),
        (3.95,  5800,   .03),
        (4.10,  7150,   .015),
        (4.28,  6050,   .012),
        (4.50,  3000,   .02),
        (4.65,  2200,   .01),
        (4.80,  500,    .01),
        ]
    for loc, h, w in peaks:
        peak = scipy.stats.norm.pdf(x_axis, loc, w)
        y_base =  y_base + peak * h /max(peak)
    
    # Add noise
    noise = rng.normal(0, noise_gain, *(x_axis.shape))
    # Round an convert to integers
    y_data = y_base + noise
    y_data = y_data.astype(np.int32)
    # Insert NaN at random positions
    nans_decision = np.random.random(x_axis.shape) > 0.1
    y_data = np.where(nans_decision, y_data, nan_array)
    return y_data
 
def main():
    r"""
    Runs the script and generate demo file.
    """
    file = "data/demofile.tsv"
    if not os.path.exists(os.path.dirname(file)):
            os.makedirs(os.path.dirname(file))
    # Start position in m
    start = 0.08
    # End position in m
    end = 5.07925
    # Distance between consecutive gages in m
    gage_length = 1.3 / 1000
    # Timestamp of the first reading
    start_time = datetime.datetime.now()
    # Measurement refresh rate in Hz
    frequency = 1.5625
    # Time increment between readings
    dt = datetime.timedelta(seconds=1/frequency)
    # Duration of the measurement
    duration = datetime.timedelta(seconds=10)
    # Standard deviation of noise
    noise_gain = 10
    # Random number generator for reproducible data
    rng = np.random.default_rng(seed=0)
    with open(file, "w", encoding="utf-8") as f:
        f.write("Test name: Getting Started" + "\n")
        f.write("Notes: Generated demo file for getting started with fosanalysis" + "\n")
        f.write("Product:   ODiSI 6102" + "\n")
        f.write("Date:  {}".format(start_time.isoformat(sep=" ")) + "\n")
        f.write("Timezone:  UTC+0" + "\n")
        f.write("File Type: ODiSI 6xxx Data File" + "\n")
        f.write("File Version:  7" + "\n")
        f.write("System Serial Number:   123456789" + "\n")
        f.write("Software Version:  2.1.0" + "\n")
        f.write("Hardware Version:   1" + "\n")
        f.write("Firmware Version:  1.6.6 (08/18/2020)" + "\n")
        f.write("FPGA Version:  v7.3.1-15016 (08/14/2020)" + "\n")
        f.write("Measurement Rate Per Channel:  {} Hz".format(frequency) + "\n")
        f.write("Gage Pitch (mm):   {}".format(gage_length*1000) + "\n")
        f.write("Standoff Cable Length (m): 50" + "\n")
        f.write("Temperature offset:    0.0" + "\n")
        f.write("Performance Mode:  Full Optimization" + "\n")
        f.write("Spatial Average Window Size (gages):   0" + "\n")
        f.write("Temporal Average Window Size (gages):  0" + "\n")
        f.write("Channel:   1" + "\n")
        f.write("Sensor Name:   GettingStartedSensor" + "\n")
        f.write("Sensor Serial Number:  FS2022CUSTOM_ 123456789_123456789" + "\n")
        f.write("Sensor Part Number:    CUSTOMER_GENERATED" + "\n")
        f.write("Sensor Type:   Strain" + "\n")
        f.write("Units: microstrain" + "\n")
        f.write("x-axis units:  m" + "\n")
        f.write("Length (m):    {}".format(end) + "\n")
        f.write("Patch cord length (m): 0" + "\n")
        f.write("Key name:  " + "\n")
        f.write("Tare name: " + "\n")
        f.write("----------------------------------------" + "\n")
        x_axis = generate_x(start, end, gage_length)
        print("x-axis", "", "", *x_axis, sep="\t", end="\n", file=f)
        # Strain data
        step = 0
        timestamp = start_time
        while dt * step <= duration:
            reading = generate_data(x_axis, rng, noise_gain)
            timestamp = start_time + dt * step
            print("{}".format(timestamp.isoformat(sep=" ")), "measurement", "strain", *reading, sep="\t", end="\n", file=f)
            step += 1
 
if __name__ == "__main__":
    main()