How to process and extract text from image

问题

I'm trying to extract text from image using python cv2. The result is pathetic and I can't figure out a way to improve my code. I believe the image needs to be processed before the extraction of text but not sure how.

I've tried to convert it into black and white but no luck.

import cv2
import os
import pytesseract
from PIL import Image
import time

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

cam = cv2.VideoCapture(1,cv2.CAP_DSHOW)

cam.set(cv2.CAP_PROP_FRAME_WIDTH, 8000)
cam.set(cv2.CAP_PROP_FRAME_HEIGHT, 6000)

while True:
    return_value,image = cam.read()
    image=cv2.cvtColor(image,cv2.COLOR_BGR2GRAY)
    image = image[127:219, 508:722]
    #(thresh, image) = cv2.threshold(image, 128, 255, cv2.THRESH_BINARY | cv2.THRESH_OTSU)
    cv2.imwrite('test.jpg',image)
    print('Text detected: {}'.format(pytesseract.image_to_string(Image.open('test.jpg'))))
    time.sleep(2)

cam.release()
#os.system('del test.jpg')

回答1:

Preprocessing to clean the image before performing text extraction can help. Here's a simple approach

Convert image to grayscale and sharpen image
Adaptive threshold
Perform morpholgical operations to clean image
Invert image

First we convert to grayscale then sharpen the image using a sharpening kernel

Next we adaptive threshold to obtain a binary image

Now we perform morphological transformations to smooth the image

Finally we invert the image

import cv2
import numpy as np

image = cv2.imread('1.jpg')
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
sharpen_kernel = np.array([[-1,-1,-1], [-1,9,-1], [-1,-1,-1]])
sharpen = cv2.filter2D(gray, -1, sharpen_kernel)
thresh = cv2.threshold(sharpen, 0, 255, cv2.THRESH_BINARY_INV + cv2.THRESH_OTSU)[1]

kernel = cv2.getStructuringElement(cv2.MORPH_RECT, (3,3))
close = cv2.morphologyEx(thresh, cv2.MORPH_CLOSE, kernel, iterations=1)
result = 255 - close

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

回答2:

Try this

    from PIL import image
    import PIL.image
    from pytesseract import image_to_string
     import pytesseract

     pytesseract.pytesseract.tesseract_cmd = '_________' 
          #tesseract executable path -- if not added to 
            environment path, if added ignore

       Output = 
         pytesseract.image_to_string(PIL.image.open('image 
            wants to read'). convert ("RBG"), Lang='eng')
       Print (output)

来源：https://stackoverflow.com/questions/57695842/how-to-process-and-extract-text-from-image

标签

python

image

OpenCV

image-processing

python-tesseract