robust-2d-unwrap 0.1.0

Robust 2D Unwrapping Algorithm by Zixin Zhao, ported to Python.

robust_2d_unwrap

The following is an implementation of the algorithm proposed in "Robust 2D phase unwrapping algorithm based on the transport of intensity equation" (DOI:10.1088/1361-6501/aaec5c) by Zixin Zhao, Hangying Zhang, Zhaoxian Xiao, Hubing Du, Yiying Zhuang, Chen Fan and Hong Zhao.

In particular, the code is directly ported from the MatLab implementation to be python compatible.

Installation with pip

pip install robust_2d_unwrap

Basic Usage

import numpy as np
from robust_2d_unwrap import unwrap
import matplotlib.pyplot as plt

# Generate a surface, with wrapped phase for every point
h,w = 640, 480
y0, x0 = (h - 1) / 2, (w - 1) / 2
y = np.arange(h)
x = np.arange(w)
Y, X = np.meshgrid(y,x, indexing='ij')
hmap = 4 * np.exp( -( ((Y - y0)**2) / (2 * 100**2) + ((X - x0)**2) / (2 * 100**2) ))
abs_phase = hmap * 2 * np.pi
wrapped_phase = (abs_phase + np.pi) % (2 * np.pi) - np.pi

# add some noise
wrapped_phase += np.random.randn(h,w) # mu=0, std=1 rad

# visualise wrapped phase
plt.imshow(wrapped_phase) # 2d headmap
plt.title('Wrapped Phase w/ Noise')
plt.show()

# wrap phase
unwrapped_phase, _ = unwrap(wrapped_phase)

# visualize result
plt.imshow(unwrapped_phase)
plt.title('Unwrapped Phase')
plt.show()

# Noise will persist, but it will not break the unwrapping
# algorithm.