surface_generation.py

import numpy as np
from math import floor
import scipy.ndimage as ndimage


def postprocess(surface):
    surface = surface / np.amax(surface)
    alpha = 0.75
    surface = np.power(surface, alpha)
    surface = ndimage.gaussian_filter(surface, sigma=2, order=0)
    norm = np.linalg.norm(surface)
    surface = surface / norm
    return surface


def binning(x, eta):
    temp = ((eta * x / 1200.0) % eta)
    return floor(temp)


def generate_surface(normalized_pitch_profile, eta, tau):
    N = len(normalized_pitch_profile)
    c = normalized_pitch_profile

    for i in range(len(c)):
        c[i] = binning(c[i], eta)

    c_for_j = c[: N - tau]
    inter_matrix_c_for_j = np.reshape(np.repeat(c_for_j, eta), [N - tau, eta])
    inter_matrix_j = np.tile(range(eta), [N - tau, 1])

    c_for_i = c[tau:]
    inter_matrix_c_for_i = np.tile(c_for_i, [eta, 1])
    inter_matrix_i = np.reshape(np.repeat(range(eta), N - tau), [eta, N - tau])

    first = (inter_matrix_i == inter_matrix_c_for_i)
    second = (inter_matrix_j == inter_matrix_c_for_j)

    s = np.dot(first.astype(int), second.astype(int))
    return s


if __name__ == '__main__':
    # Sanity check
    normalized = [1, 2, 3, 4, 5, 6, 7, 8, 333, 876]
    eta = 5
    tau = 2
    generate_surface(normalized,eta,tau)