Text binarization

问题

I'd like to binarize this image:

to use it with tesseract-ocr. Currently, I managed to get this:

But I need clear image with only text, without black background parts, like this one:

My current code:

img = cv2.imread(path, 0)
blur = cv2.GaussianBlur(img, (3, 3), 0)
filtered = cv2.adaptiveThreshold(img, 255, cv2.ADAPTIVE_THRESH_GAUSSIAN_C, cv2.THRESH_BINARY, 405, 1)
bitnot = cv2.bitwise_not(filtered)
cv2.imshow('image', bitnot)
cv2.imwrite("h2kcw2/out1.png", bitnot)
cv2.waitKey(0)
cv2.destroyAllWindows()

回答1:

A regular threshold can present a good result:

img = cv2.imread(path, 0)
ret, thresh = cv2.threshold(img, 70, 255, cv2.THRESH_BINARY_INV)
cv2.imshow('image', thresh)
cv2.imwrite("h2kcw2/out1.png", thresh)
cv2.waitKey(0)
cv2.destroyAllWindows()

来源：https://stackoverflow.com/questions/26185550/text-binarization