import cv2
import numpy as np

gray = cv2.imread('D:\PT\pic\pcg.jpg', cv2.IMREAD_GRAYSCALE)
scalex = 0.5
scaley = 0.5
X, Y = gray.shape[1]*scalex, gray.shape[0]*scaley
gray = cv2.resize(gray, (int(X), int(Y)))

binary_thresh, bin = cv2.threshold(gray, 150, 255, cv2.THRESH_BINARY)
Otsu_thresh, otsu = cv2.threshold(gray, 0, 255, cv2.THRESH_OTSU)
triangle_thresh, tri = cv2.threshold(gray, 0, 255, cv2.THRESH_TRIANGLE)
adapt = cv2.adaptiveThreshold(gray, 255, cv2.ADAPTIVE_THRESH_MEAN_C,
cv2.THRESH_BINARY, 13, 15)
gauss = cv2.adaptiveThreshold(gray, 255, cv2.ADAPTIVE_THRESH_GAUSSIAN_C,
cv2.THRESH_BINARY, 21, 15)

cv2.imshow('Binary', bin)
cv2.imshow('Otsu', otsu)
cv2.imshow('Triangle', tri)
cv2.imshow('Adaptive', adapt)
cv2.imshow('Gauss', gauss)
cv2.waitKey(0)