Multi-Otsu Threshold

Multi-Otsu Threshold

import matplotlib

import matplotlib.pyplot as plt

import numpy as np

from skimage import data

from skimage.filters import threshold_multiotsu

# Setting the font size for all plots.

matplotlib.rcParams['font.size'] = 9

# The input image.

image = data.camera()

# Applying multi-Otsu threshold for the default value, generating

# three classes.

thresholds = threshold_multiotsu(image)

# Using the threshold values, we generate the three regions.

regions = np.digitize(image, bins=thresholds)

fig, ax = plt.subplots(nrows=1, ncols=3, figsize=(10, 3.5))

# Plotting the original image.

ax[0].imshow(image, cmap='gray')

ax[0].set_title('Original')

ax[0].axis('off')

# Plotting the histogram and the two thresholds obtained from

# multi-Otsu.

ax[1].hist(image.ravel(), bins=255)

ax[1].set_title('Histogram')

for thresh in thresholds:

ax[1].axvline(thresh, color='r')

# Plotting the Multi Otsu result.

ax[2].imshow(regions, cmap='jet')

ax[2].set_title('Multi-Otsu result')

ax[2].axis('off')

plt.subplots_adjust()

plt.show()

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