Extracting particular text associated value from an image

Question

I have an image, and from the image I want to extract key and value pair details.

As an example, I want to extract the value of "MASTER-AIRWAYBILL NO:"

I have written to extract the entire text from the image using python opencv and OCR, but I don't have any clue how to extract only the value for "MASTER-AIRWAYBILL NO:" from the entire result text of the image.

Please find the code:

import cv2
import numpy as np
import pytesseract
from PIL import Image
print ("Hello")
src_path = "C:\\Users\Venkatraman.R\Desktop\\alpha_bill.jpg"
pytesseract.pytesseract.tesseract_cmd = r"C:\Program Files (x86)\Tesseract-OCR\tesseract.exe"


print (src_path)


# Read image with opencv
img = cv2.imread(src_path)

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

# Apply dilation and erosion to remove some noise
kernel = np.ones((1, 1), np.uint8)
img = cv2.dilate(img, kernel, iterations=1)
img = cv2.erode(img, kernel, iterations=1)

# Write image after removed noise
cv2.imwrite(src_path + "removed_noise.png", img)

#  Apply threshold to get image with only black and white
#img = cv2.adaptiveThreshold(img, 255, cv2.ADAPTIVE_THRESH_GAUSSIAN_C, cv2.THRESH_BINARY, 31, 2)

# Write the image after apply opencv to do some ...
cv2.imwrite(src_path + "thres.png", img)

# Recognize text with tesseract for python
result = pytesseract.image_to_string(Image.open(src_path + "thres.png"))


# Remove template file
#os.remove(temp)


print ('--- Start recognize text from image ---')
print (result)

So output should be like:

MASTER-AIRWAYBILL NO: 157-46637194

Answer 1

You can use pytesseract image_to_string() and a regex to extract the desired text, i.e.:

from PIL import Image
import pytesseract, re
f = "ocr.jpg"
t = pytesseract.image_to_string(Image.open(f))
m = re.findall(r"MASTER-AIRWAYBILL NO: [\d—-]+", t)
if m:
    print(m[0])

---

Output:

MASTER-AIRWAYBILL NO: 157—46637194