2.6.8.21. Segmentation with Gaussian mixture modelsΒΆ

This example performs a Gaussian mixture model analysis of the image histogram to find the right thresholds for separating foreground from background.

../../../_images/sphx_glr_plot_GMM_001.png
import numpy as np
from scipy import ndimage
import matplotlib.pyplot as plt
from sklearn.mixture import GaussianMixture
np.random.seed(1)
n = 10
l = 256
im = np.zeros((l, l))
points = l*np.random.random((2, n**2))
im[(points[0]).astype(np.int), (points[1]).astype(np.int)] = 1
im = ndimage.gaussian_filter(im, sigma=l/(4.*n))
mask = (im > im.mean()).astype(np.float)
img = mask + 0.3*np.random.randn(*mask.shape)
hist, bin_edges = np.histogram(img, bins=60)
bin_centers = 0.5*(bin_edges[:-1] + bin_edges[1:])
classif = GaussianMixture(n_components=2)
classif.fit(img.reshape((img.size, 1)))
threshold = np.mean(classif.means_)
binary_img = img > threshold
plt.figure(figsize=(11,4))
plt.subplot(131)
plt.imshow(img)
plt.axis('off')
plt.subplot(132)
plt.plot(bin_centers, hist, lw=2)
plt.axvline(0.5, color='r', ls='--', lw=2)
plt.text(0.57, 0.8, 'histogram', fontsize=20, transform = plt.gca().transAxes)
plt.yticks([])
plt.subplot(133)
plt.imshow(binary_img, cmap=plt.cm.gray, interpolation='nearest')
plt.axis('off')
plt.subplots_adjust(wspace=0.02, hspace=0.3, top=1, bottom=0.1, left=0, right=1)
plt.show()

Total running time of the script: ( 0 minutes 0.308 seconds)

Gallery generated by Sphinx-Gallery