Text Recognition with pytesseract and cv2 or other libs

Python Help
1

sample
Please download the png file and save it as ‘sample.png’.

I want to extract english characters in the png file.

import cv2
import pytesseract

img = cv2.imread("/tmp/sample.png")
gry = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
thr = cv2.adaptiveThreshold(gry, 255, cv2.ADAPTIVE_THRESH_MEAN_C,
                            cv2.THRESH_BINARY_INV, 23, 100)
bnt = cv2.bitwise_not(thr)
txt = pytesseract.image_to_string(bnt, config="--psm 6")
res = ''.join(i for i in txt if i.isalnum())
print(res)

The output is

ee

It get wrong output ,how can extract English characters in it then?