python+Opencvによる画像処理9（2値化）

二値化法の比較。

import pylab as plt
plt.rcParams['font.family'] = 'IPAexGothic'
plt.rcParams['font.size'] = 12

import cv2
import numpy as np

im = cv2.imread("cat.jpg")

im_gray = cv2.cvtColor(im, cv2.COLOR_BGR2GRAY)

#Adaptive Gaussian Thresholding
th1 = cv2.adaptiveThreshold(im_gray,255,cv2.ADAPTIVE_THRESH_GAUSSIAN_C,\
            cv2.THRESH_BINARY,11,2)

#フィルター+大津
blur = cv2.bilateralFilter(im_gray,6,12,3)
ret,th2 = cv2.threshold(blur,0,255,cv2.THRESH_BINARY+cv2.THRESH_OTSU)
#フィルターのみ
ret,th3 = cv2.threshold(blur,70,255,cv2.THRESH_BINARY_INV)


print ret 
plt.subplot(2,2,1),plt.imshow(im,'gray')
plt.title('input image')
plt.subplot(2,2,2),plt.imshow(th1,'gray')
plt.title('Adaptive Gaussian Thresholding')
plt.subplot(2,2,3),plt.imshow(th2,'gray')
plt.title(u"フィルター+大津")
plt.subplot(2,2,4),plt.imshow(th3,'gray')
plt.title(u"フィルターのみ")
 
plt.show()

cv2.waitKey(0)
cv2.destroyAllWindows()