OpenPIV on the bridgepile_wake¶

from openpiv import tools, pyprocess, validation, filters, scaling 

import numpy as np
import matplotlib.pyplot as plt
%matplotlib inline

import imageio

frame_a  = tools.imread('../test8/frame0001.tif')
frame_b  = tools.imread('../test8/frame0002.tif')

# %pdb
# np.seterr(all="raise")
winsize = 24 # pixels
searchsize = 48  # pixels, search in image B
overlap = 12 # pixels
dt = 1./30 # sec, assume 30 fps

frame_a[:600,:] = 0  # basically masking out the non-illuminated region
frame_b[:600,:] = 0


u0, v0, sig2noise = pyprocess.extended_search_area_piv(frame_a.astype(np.int32), 
                                                       frame_b.astype(np.int32), 
                                                       window_size=winsize, 
                                                       overlap=overlap, dt=dt, 
                                                       search_area_size=searchsize, 
                                                       sig2noise_method='peak2peak',
                                                      correlation_method='linear',
                                                      normalized_correlation=True)

x, y = pyprocess.get_coordinates(frame_a.shape,searchsize, overlap)

u1, v1, mask = validation.sig2noise_val( u0, v0, sig2noise, threshold = 1.2)

u2, v2 = filters.replace_outliers( u1, v1, method='localmean', max_iter=1, kernel_size=3)

# x, y, u3, v3 = scaling.uniform(x, y, u2, v2, scaling_factor = 1. )

x, y, u2, v2 = tools.transform_coordinates(x, y, u2, v2)
tools.save(x, y, u2, v2, mask, 'exp1_001.txt' )

# tools.display_vector_field('exp1_001.txt', scaling_factor=100., width=0.0025)

from openpiv.windef import Settings, Multiprocesser, piv