mirror of
https://github.com/wassname/scikit-image.git
synced 2026-06-29 00:39:44 +08:00
Tony S Yu
46 lines
946 B
Python
46 lines
946 B
Python
"""
|
|
============
|
|
Thresholding
|
|
============
|
|
|
|
Thresholding is used to create a binary image. This example uses Otsu's method
|
|
to calculate the threshold value.
|
|
|
|
Otsu's method calculates an "optimal" threshold (marked by a red line in the
|
|
histogram below) by maximizing the variance between two classes of pixels,
|
|
which are separated by the threshold. Equivalently, this threshold minimizes
|
|
the intra-class variance.
|
|
|
|
.. [1] http://en.wikipedia.org/wiki/Otsu's_method
|
|
|
|
"""
|
|
|
|
import matplotlib.pyplot as plt
|
|
|
|
from skimage.data import camera
|
|
from skimage.filter import threshold_otsu
|
|
|
|
|
|
image = camera()
|
|
thresh = threshold_otsu(image)
|
|
binary = image > thresh
|
|
|
|
plt.figure(figsize=(10, 3.5))
|
|
plt.subplot(1, 3, 1)
|
|
plt.imshow(image)
|
|
plt.title('original')
|
|
plt.axis('off')
|
|
|
|
plt.subplot(1, 3, 2)
|
|
plt.hist(image)
|
|
plt.title('histogram')
|
|
plt.axvline(thresh, color='r')
|
|
|
|
plt.subplot(1, 3, 3)
|
|
plt.imshow(binary)
|
|
plt.title('thresholded')
|
|
plt.axis('off')
|
|
|
|
plt.show()
|
|
|