from skimage import io, color
import matplotlib.pyplot as plt


def change_grey_to_white(origin, new):
    """
    Change background color for image, such as signature
    :param origin: the path of original image
    :param new: the path of new image
    :return: None
    """
    # img = io.imread('./origin.jpeg')
    img = io.imread(origin)
    io.imshow(img)
    plt.show()
    img_gray = color.rgb2gray(img)
    rows, cols = img_gray.shape
    for i in range(rows):
        for j in range(cols):
            if img_gray[i, j] <= 0.5:
                img_gray[i, j] = 0
            else:
                img_gray[i, j] = 1
    io.imshow(img_gray)
    plt.show()
    io.imsave(new, img_gray)

# example
change_grey_to_white('./origin.jpeg', 'new.jpeg')

from skimage import io
import numpy as np


def change_pixel_color(pixel, old_pixel, new_pixel=None, error=60):
    """
    change color for pixel if pixel in range [old_pixel-error, old_pixel+error]
    :param pixel:
    :param old_pixel:
    :param new_pixel:
    :param error:
    :return: the new pixel
    """
    if new_pixel is None:
        new_pixel = [255, 255, 255]
    similar = True
    for i in abs(pixel - old_pixel):
        if i > error:
            similar = False
            break
    if similar:
        return new_pixel
    else:
        return pixel


def change_background(origin_path, new_path, new_color, error=60):
    """
    change background, auto detect background
    :param origin_path:
    :param new_path:
    :param new_color: target background color
    :param error: the error for change color
    :return: None
    """
    img = io.imread(origin_path)
    bg = img[10:30, 10:30, :]
    bg_pixel = [1.0 * np.sum(bg[:, :, channel])/bg[:, :, channel].size for channel in range(3)]
    print("background color: %s" % bg_pixel)
    new_img = np.array([[change_pixel_color(pixel, [0, 160, 234], new_color, error) for pixel in row] for row in img])
    io.imshow(new_img)
    # import matplotlib.pyplot as plt
    # plt.show()
    io.imsave(new_path, new_img)
    

# example
change_background(origin_path="origin.jpeg",
                  new_path='new.jpeg',
                  new_color=[0, 255, 255])