3.3.11.7. Otsu thresholding

This example illustrates automatic Otsu thresholding.

import matplotlib.pyplot as plt
from skimage import data
from skimage import filters
from skimage import exposure

camera = data.camera()
val = filters.threshold_otsu(camera)

hist, bins_center = exposure.histogram(camera)

plt.figure(figsize=(9, 4))
plt.subplot(131)
plt.imshow(camera, cmap="gray", interpolation="nearest")
plt.axis("off")
plt.subplot(132)
plt.imshow(camera < val, cmap="gray", interpolation="nearest")
plt.axis("off")
plt.subplot(133)
plt.plot(bins_center, hist, lw=2)
plt.axvline(val, color="k", ls="--")

plt.tight_layout()
plt.show()