import cv2
import numpy as np
img = cv2.imread('bookpage.jpg')
retval, threshold = cv2.threshold(img, 12, 255, cv2.THRESH_BINARY)
grayscaled = cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)
retval2, threshold2 = cv2.threshold(img, 12, 255, cv2.THRESH_BINARY)
gaus=cv2.adaptiveThreshold(grayscaled, 255, cv2.ADAPTIVE_THRESH_GAUSSIAN_C,cv2.THRESH_BINARY,115,1)
retval2,otsu = cv2.threshold(grayscaled,125,255,cv2.THRESH_BINARY+cv2.THRESH_OTSU)
cv2.imshow('original',img)
cv2.imshow('threshold',threshold)
cv2.imshow('threshold2',threshold2)
cv2.imshow('gaus',gaus)
cv2.imshow('otsu',otsu)
cv2.waitKey(0)
cv2.destroyAllWindows()