def histeq(path):
    from PIL import Image
    from matplotlib import pyplot as plt
    import numpy as np

    image = np.array(Image.open(path).convert('L'))

    imhist,bins = np.histogram(image.flatten(),bins=255, normed=True)

    cdf = imhist.cumsum()
    cdf = 255 * cdf / cdf[-1]

    im2 = np.interp(image.flatten(), bins[:-1], cdf).reshape(image.shape)

    plt.figure(figsize=(12, 6))
    plt.gray()

    plt.subplot(221)
    plt.hist(image.flatten(), 256)
    plt.subplot(222)
    plt.imshow(image)
    plt.subplot(223)
    plt.hist(im2.flatten(), 256)
    plt.subplot(224)
    plt.imshow(im2)


    plt.show()






if __name__ == '__main__':
    path = '../data/imgs/night.jpg'
    histeq(path)