Python center array image

center_array_image.py

def center_image(img):
    """Return a centered image.
    :param img:
    """
    col_sum = np.where(np.sum(img, axis=0) > 0)
    row_sum = np.where(np.sum(img, axis=1) > 0)
    y1, y2 = row_sum[0][0], row_sum[0][-1]
    x1, x2 = col_sum[0][0], col_sum[0][-1]

    cropped_image = img[y1:y2, x1:x2]

    zero_axis_fill = (img.shape[0] - cropped_image.shape[0])
    one_axis_fill = (img.shape[1] - cropped_image.shape[1])

    top = zero_axis_fill / 2
    bottom = zero_axis_fill - top
    left = one_axis_fill / 2
    right = one_axis_fill - left

    padded_image = pad_image(cropped_image, top, left, bottom, right)

    return padded_image