Optical Flow examples

skimage_optical_flow_demo.py

from matplotlib import pyplot as plt
%matplotlib inline

from skimage.color import hsv2rgb
from skimage.color import rgb2gray
from skimage.data import stereo_motorcycle
from skimage.registration import optical_flow_tvl1
import numpy as np

image0, image1, disp = stereo_motorcycle()

# convert the images to gray level: color is not supported.
image0 = rgb2gray(image0)
image1 = rgb2gray(image1)
flow = optical_flow_tvl1(image1, image0)

# display dense optical flow
flow_x = flow[1, :, :]
flow_y = flow[0, :, :]
mag_map = np.hypot(flow_x, flow_y)  # magnitude
mag_map *= 255 / mag_map.max()
mag_map = mag_map.astype('uint8')

angle_map = np.arctan2(flow_y, flow_x) + np.pi  # direction
angle_map *= (180./np.pi)
angle_map = np.clip(angle_map, 0, 180)
angle_map = angle_map.astype('uint8')

# hsv color space
s_map = (np.ones(mag_map.shape) * 255).astype('uint8')
img_hsv = np.dstack((angle_map, s_map, mag_map))
img_rgb = hsv2rgb(img_hsv)
plt.imshow(img_rgb)