smoothen edges of pixelated binary image python code

Question

I'm using pytesseract to convert images into text, however the accuracy isn't 100% since the images pixelate on resizing. Applying gaussian blur would smoothen the edges but blur the image making it impossible for OCR to detect text. What sort of filter would smoothen the edges without blurring the image too much. The image looks something like this

Image

Answer 1

You can median blur image then try a series of morphological transformations, specifically cv2.MORPH_CLOSE with a 3x3 kernel seems to work well here. You can play with the kernel size and number of iterations to get desired results

import cv2

image = cv2.imread('1.png')

blur = cv2.medianBlur(image, 7)
gray = cv2.cvtColor(blur, cv2.COLOR_BGR2GRAY)
thresh = cv2.threshold(gray,125, 255,cv2.THRESH_BINARY_INV)[1]

kernel = cv2.getStructuringElement(cv2.MORPH_RECT, (3,3))
close = cv2.morphologyEx(thresh, cv2.MORPH_CLOSE, kernel, iterations=2)
result = 255 - close

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