add lab_3

lab_3/p3_localisation_codebase/fingerprinting_skeleton.py

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+import numpy as np
+import os
+import glob
+import sys
+import matplotlib.pyplot as plt
+from statsmodels.distributions.empirical_distribution import ECDF
+from scipy.stats import norm
+
+
+#
+# Implements the HORUS probabilistic WiFi Localization system
+# ( Mobile and Sensor Networks course - University of Oxford )
+# April 2016
+#
+
+def init():
+    print("")
+    print ('*' * 60)
+    print (' The Horus Localization System')
+    print (" Mobile and Sensor Networks course - University of Oxford")
+    print ('*' * 60)
+    print ("")
+    print ("")
+    return
+
+
+# Function to load the wifi RSS data
+def load_wifi_data(data_folder, n_samples, n_ap):
+    """
+    :param data_folder: Location of WiFi RSS data
+    :param n_samples: Number of RSS samples collected for each location
+    :param n_ap: Number of access points
+    :return: train and test wifi databases
+    """
+
+    sys.stdout.write("-> Loading files...")
+
+    train_path = data_folder + "/" + "wifiData/"
+    test_path = data_folder + "/" + "testWifiData/"
+
+    # We are going to examine two cases with 3 and 5 Access Points (APs)
+    if n_ap == 3:
+        ap_index = [1, 2, 3]
+    else:
+        ap_index = [1, 2, 3, 4, 5]
+
+    # We read the wifi RSS collected in the training phase to built the Wifi database
+    os.chdir(train_path)
+    train_files = glob.glob("*.txt")
+    n_locations = len(train_files)
+    wifi_database = np.zeros((n_locations, (n_ap * n_samples) + 3))
+    ap_name = "AP_"
+
+    file_count = -1
+    for f in train_files:
+        file_count += 1
+
+        if n_ap == 3:
+            ap_counter = [0, 0, 0]
+        else:
+            ap_counter = [0, 0, 0, 0, 0]
+
+        fid = open(f, 'r')
+        wifi_database[file_count, 0] = file_count
+        first_line = 0
+        for line in fid:
+            data = line.split()
+            if first_line == 0:
+                first_line += 1
+                wifi_database[file_count, 1] = int(data[0])
+                wifi_database[file_count, 2] = int(data[1])
+            else:
+                for idx in range(1, n_ap + 1):
+                    if data[1] == (ap_name + str(idx)):
+                        ap_counter[idx - 1] += 1
+                        db_index = int((n_samples * (ap_index[idx - 1] - 1)) + 2 + ap_counter[idx - 1])
+                        wifi_database[file_count, db_index] = float(data[2])
+    os.chdir("../..")
+
+    # Now we load the test points. Wifi data collected at unknown locations.
+    os.chdir(test_path)
+    test_files = glob.glob("*.txt")
+    test_files.sort()
+    n_locations = len(test_files)
+    test_db = np.zeros((n_locations, (n_ap * (n_samples - 10)) + 3))
+
+    file_count = -1
+    for f in test_files:
+        file_count += 1
+
+        if n_ap == 3:
+            ap_counter = [0, 0, 0]
+        else:
+            ap_counter = [0, 0, 0, 0, 0]
+
+        fid = open(f, 'r')
+        test_db[file_count, 0] = file_count
+        first_line = 0
+        for line in fid:
+            data = line.split()
+            if first_line == 0:
+                first_line += 1
+                test_db[file_count, 1] = int(data[0])
+                test_db[file_count, 2] = int(data[1])
+            else:
+                for idx in range(1, n_ap + 1):
+                    if data[1] == (ap_name + str(idx)):
+                        ap_counter[idx - 1] += 1
+                        db_index = int(((n_samples - 10) * (ap_index[idx - 1] - 1)) + 2 + ap_counter[idx - 1])
+                        test_db[file_count, db_index] = float(data[2])
+
+    sys.stdout.write("done\n")
+    return wifi_database, test_db
+
+
+# Visualize fingerprint locations and locations of APs
+def show_fingerprints(train_db, n_ap):
+    """
+    :param train_db: RSS points collected at known locations
+    :param n_ap: Number of APs
+    :return: null
+    """
+    sys.stdout.write("-> Displaying fingerprints...")
+
+    if n_ap == 3:
+        ap_loc = np.array([[6, 6], [8, 16], [18, 14]])
+    else:
+        ap_loc = np.array([[6, 6], [8, 16], [18, 14], [16, 4], [12, 10]])
+
+    plt.figure()
+    plt.plot(train_db[:, 1], train_db[:, 2], 'co', markersize=17)
+    plt.plot(ap_loc[:, 0], ap_loc[:, 1], 'b*', markersize=10)
+    major_ticks = np.arange(-2, 22, 2)
+    axes = plt.gca()
+    axes.set_xlim([-2, 22])
+    axes.set_ylim([-2, 22])
+    axes.set_xticks(major_ticks)
+    axes.set_yticks(major_ticks)
+    plt.grid(True)
+    plt.xlabel("X -> m")
+    plt.ylabel("Y -> m")
+    plt.title("Cyan points: fingerprint locations, Blue points: Access Points")
+    plt.show(block=False)
+    sys.stdout.write("done\n")
+
+    return
+
+
+# Fit a normal distribution to the RSS data
+def fit_data(train_db, n_samples, n_ap):
+    """
+    :param train_db: RSS points collected at known locations
+    :param n_samples: Number of RSS samples per location
+    :param n_ap: Number of access points
+    :return: Wifi fingerprint database; We approximate the RSS at each location with a Gaussian
+    """
+
+    sys.stdout.write("-> Modeling RSS with Gaussian dist...")
+
+    n_loc = len(train_db)
+
+    # Initialize Wifi database
+    wifi_db = np.zeros((n_loc, 3 + (n_ap * 2)))
+
+    for i in range(0, n_loc):
+        wifi_db[i, 0] = i
+        wifi_db[i, 1] = train_db[i, 1]
+        wifi_db[i, 2] = train_db[i, 2]
+        for j in range(0, n_ap):
+            ind_start = int((n_samples * j) + 3)
+            ind_end = int((j + 1) * n_samples + 3)
+            dat = train_db[i, ind_start:ind_end]
+            [mu, sigma] = norm.fit(dat)
+            wifi_db[i, (j * 2) + 3] = mu
+            wifi_db[i, (j * 2) + 4] = sigma
+
+    sys.stdout.write("done\n")
+    return wifi_db
+
+
+# Plot Wifi RSS histogram per location - Fit a  Gaussian Dist to the data
+def plot_histogram(train_db, location, n_ap, n_samples):
+    """
+    :param train_db: RSS points collected at known locations
+    :param location: Location to plot the RSS histogram
+    :param n_ap: Number of access points
+    :param n_samples: Number of RSS samples per location
+    :return: null
+    """
+
+    sys.stdout.write("-> Visualizing histograms...")
+
+    if (location < 0) or (location >= len(train_db)):
+        location = 0
+
+    # Extract the RSS data from :param location
+    for i in range(0, n_ap):
+        ind_start = int((n_samples * i) + 3)
+        ind_end = int((i + 1) * n_samples + 3)
+        dat = train_db[location, ind_start:ind_end]
+
+        # Plot the RSS histogram
+        plt.figure()
+        n_bins = round(np.sqrt(len(dat)))
+        plt.hist(dat, bins=n_bins, normed=True, alpha=0.6, color='g')
+
+        # Approximate the histogram with a Gaussian distribution
+        [mu, sigma] = norm.fit(dat)
+        x = np.linspace(mu - 4 * sigma, mu + 4 * sigma, 500)
+        y = norm.pdf(x, mu, sigma)
+        plt.plot(x, y, 'r-', linewidth=2)
+        plt.xlabel('Wifi RSS -> dBm')
+        plt.ylabel('Frequency')
+        plt.title('RSS histogram of AP=%d , Norm(%.2f,%.2f)' % (i + 1, mu, sigma))
+        plt.grid(True)
+        plt.show(block=False)
+
+    sys.stdout.write("done\n")
+    return
+
+
+# The Horus probabilistic localization system
+def predict(wifi_db, test_db, n_ap, n_samples):
+    """
+    :param wifi_db: The Wifi database
+    :param test_db: Wifi RSS points an the unknown locations
+    :param n_ap: Number of APs
+    :param n_samples: Samples per location
+    :return: The estimated locations
+    """
+
+    sys.stdout.write("-> Running Horus...")
+
+    predicted_loc = np.zeros((len(test_db), 2))
+    actual_loc = test_db[:, 1:3]
+
+    # - - - - WRITE YOUR CODE HERE - - - - -
+
+    # - - - - - - - - - - - - - - - - - - - -
+
+    sys.stdout.write("done\n")
+    return actual_loc, predicted_loc
+
+
+# Plot the actual and estimated locations
+def plot_path(actual_loc, predicted_loc, n_ap):
+    """
+    :param actual_loc: Actual locations
+    :param predicted_loc: Estimated locations
+    :param n_ap: Number of APs
+    :return: null
+    """
+    sys.stdout.write("-> Visualizing estimated trajectory...")
+
+    if n_ap == 3:
+        ap_loc = np.array([[6, 6], [8, 16], [18, 14]])
+    else:
+        ap_loc = np.array([[6, 6], [8, 16], [18, 14], [16, 4], [12, 10]])
+
+    plt.figure()
+    plt.plot(ap_loc[:, 0], ap_loc[:, 1], 'b*', markersize=15)
+    plt.plot(actual_loc[:, 0], actual_loc[:, 1], 'go-', linewidth=2)
+    plt.plot(predicted_loc[:, 0], predicted_loc[:, 1], 'ro-', linewidth=2)
+
+    major_ticks = np.arange(-2, 22, 2)
+
+    axes = plt.gca()
+    axes.set_xlim([-2, 22])
+    axes.set_ylim([-2, 22])
+    axes.set_xticks(major_ticks)
+    axes.set_yticks(major_ticks)
+    plt.xlabel('X -> m')
+    plt.ylabel('Y -> m')
+    plt.title('Green line = actual path , Red line = estimated path, Blue points = AP loc')
+    plt.grid(True)
+    plt.show(block=False)
+
+    sys.stdout.write("done\n")
+    return
+
+
+# Calculate and plot the localization error
+def plot_error(actual_loc, predicted_loc):
+    """
+    :param actual_loc: Actual locations
+    :param predicted_loc: Estimated Locations
+    :return: null
+    """
+
+    sys.stdout.write("-> Calculating localization error...")
+
+    err = np.zeros((1, len(actual_loc)))
+    for i in range(0, len(actual_loc)):
+        err[0, i] = np.sqrt((actual_loc[i, 0] - predicted_loc[i, 0]) ** 2 +
+                            (actual_loc[i, 1] - predicted_loc[i, 1]) ** 2)
+
+    mean_err = np.mean(err)
+
+    ecdf = ECDF(err[0, :])
+    plt.figure()
+    plt.plot(ecdf.x, ecdf.y)
+    plt.grid(True)
+    plt.xlabel('error -> m')
+    plt.ylabel('Probability')
+    plt.title('Error CDF , Mean error = %.3f' % mean_err)
+    plt.show(block=False)
+
+    sys.stdout.write("done\n")
+    return
+
+
+# --------------------------------------------------------------
+# MAIN CODE
+# --------------------------------------------------------------
+
+# ----- Constants -----
+# Number of measurements per location
+nSamples = 60
+
+# ---- Configure Parameters -----
+# Select Dataset (set1 or set2)
+data_set = "set1"
+
+# Visualize the RSS in location = loc
+loc = 2
+
+# ----- Run System ------
+
+# set1 contains 3 access points and set2 5 access points
+if data_set == "set1":
+    nAP = 3
+else:
+    nAP = 5
+
+init()
+
+# Load the RSS measurements from file
+(trainDB, testDB) = load_wifi_data(data_set, nSamples, nAP)
+
+# Show fingerprint locations
+show_fingerprints(trainDB, nAP)
+
+# Plot the RSS histogram and approximate it with a Gaussian
+plot_histogram(trainDB, loc, nAP, nSamples)
+
+# Fit Gaussian distribution to the RSS measurements
+wifiDB = fit_data(trainDB, nSamples, nAP)
+
+# Run the localization algorithm
+# Estimate the unknown location given RSS measurements at that location
+(actualLoc, predictedLoc) = predict(wifiDB, testDB, nAP, nSamples)
+
+# Visualize the actual and estimated locations
+# plot_path(actualLoc, predictedLoc, nAP)
+
+# Plot the mean localization error and error CDF
+# plot_error(actualLoc, predictedLoc)
+
+ans = raw_input("Press any key to exit")