__all__ = ['histogram_equalize_image']
import numpy as np
import ants
from ants.decorators import image_method
[docs]
@image_method
def histogram_equalize_image(image, number_of_histogram_bins=256):
"""
Histogram equalize image
# from http://www.janeriksolem.net/histogram-equalization-with-python-and.html
Arguments
---------
image : ANTsImage
source image
number_of_histogram_bins : integer
number of bins for cumulative histogram
Example
-------
>>> import ants
>>> src_img = ants.image_read(ants.get_data('r16'))
>>> src_img_eq = ants.histogram_equalize_image(src_img)
"""
image_array = image.numpy()
image_histogram, bins = np.histogram(image_array.flatten(), number_of_histogram_bins, density=True)
cdf = image_histogram.cumsum()
cdf = image_array.max() * cdf / cdf[-1]
image_array_equalized_flat = np.interp(image_array.flatten(), bins[:-1], cdf)
image_array_equalized = image_array_equalized_flat.reshape(image_array.shape)
image_array_equalized = ( ( image_array_equalized - image_array_equalized.min() ) /
( image_array_equalized.max() - image_array_equalized.min() ) )
image_array_equalized = image_array_equalized * ( image_array.max() - image_array.min() ) + image_array.min()
image_equalized = ants.from_numpy(image_array_equalized)
return ants.copy_image_info(image, image_equalized)