Pytesseract 无法识别图像中的数字

Question

Pytesseract fails to recognize digits 6 and 8 . It recognizes

• 6 as 5 and
• 5 as 5 ,
• 3 as 8 and
• 8 as 8 ,
• Oct as 0c: or 0:: and
• Wed as Men .

The script used:

config= "-c tessedit_char_whitelist=01234567890.:ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz -psm 3 -oem 0"
text = pytesseract.image_to_string(image, config=config)

Tried also using the different psm number from 1-12 but no luck. Increasing contrast results in more numbers not recognized:

kernel = np.ones((2,2),np.uint8)
dilation = cv2.dilate(im, kernel)#,iterations = 1)
text = pytesseract.image_to_string(dilation, config=config)

Raw data:

After running the script:

After running new script:

Answer 1

Some preprocessing to clean/smooth the image before throwing it into Pytesseract can help. Specifically, morphological operations to close small holes and remove noise can enhance the image. Also applying sharpening filters may help as well. Also adjusting the kernel size or type may help. I believe --psm 6 is the best here since the image is a single uniform block of text. Here's what I get after a simple morph close

import cv2
import pytesseract

pytesseract.pytesseract.tesseract_cmd = r"C:\Program Files\Tesseract-OCR\tesseract.exe"

image = cv2.imread('1.png',0)
thresh = cv2.threshold(image, 150, 255, cv2.THRESH_BINARY_INV)[1]

kernel = cv2.getStructuringElement(cv2.MORPH_RECT, (2,2))
close = cv2.morphologyEx(thresh, cv2.MORPH_CLOSE, kernel)
result = 255 - close

data = pytesseract.image_to_string(result, lang='eng',config='--psm 6')
print(data)

cv2.imshow('thresh', thresh)
cv2.imshow('result', result)
cv2.imshow('close', close)
cv2.waitKey()