is it possible to extracting text inside colored background region using opencv in python?

Question

I having the following table area from the original image:

I'm trying extract the text,from this table.But when using threshold the whole gray regions get darkening.For example like below,

The threshold type which i did used,

thresh_value = cv2.threshold(original_gray, 128, 255, cv2.THRESH_BINARY_INV +cv2.THRESH_OTSU)[1]

is it possible to extract and change gray background into white and lets remain text pixel as it is if black then?

Answer 1

You should use adaptive thresholding in Python/OpenCV.

Input:

import cv2
import numpy as np

# read image
img = cv2.imread("text_table.jpg")

# convert img to grayscale
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)

# do adaptive threshold on gray image
thresh = cv2.adaptiveThreshold(gray, 255, cv2.ADAPTIVE_THRESH_MEAN_C, cv2.THRESH_BINARY, 11, 11)

# write results to disk
cv2.imwrite("text_table_thresh.jpg", thresh)

# display it
cv2.imshow("thresh", thresh)
cv2.waitKey(0)

Result