Jupyter Snippet CB2nd 01_exposure

11.1. Manipulating the exposure of an image

import numpy as np
import matplotlib.pyplot as plt
import skimage.exposure as skie
%matplotlib inline

img = plt.imread('https://github.com/ipython-books/'
                 'cookbook-2nd-data/blob/master/'
                 'beach.png?raw=true')[..., 0]

def show(img):
    # Display the image.
    fig, (ax1, ax2) = plt.subplots(1, 2,
                                   figsize=(12, 3))

    ax1.imshow(img, cmap=plt.cm.gray)
    ax1.set_axis_off()

    # Display the histogram.
    ax2.hist(img.ravel(), lw=0, bins=256)
    ax2.set_xlim(0, img.max())
    ax2.set_yticks([])

    plt.show()

show(img)

show(skie.rescale_intensity(
    img, in_range=(0.4, .95), out_range=(0, 1)))

show(skie.equalize_adapthist(img))