How to extract decimal in image with Pytesseract

问题

Above is the image ,I have tried everything I could get from SO or google ,nothing seems to work. I can not get the exact value in image , I should get 2.10 , Instead it always get 210.

And it is not limited to this image only any image which have a decimal before number 1 tesseract ignores the decimal value.

 def returnAllowedAmount(self,imgpath):
        th = 127
        max_val = 255
        img = cv2.imread(imgpath,0) #Load Image in Memory
        img = cv2.resize(img, None, fx=2.5, fy=2.5, interpolation=cv2.INTER_CUBIC) #rescale Image
        img = cv2.medianBlur(img, 1)
        ret , img = cv2.threshold(img,th,max_val,cv2.THRESH_TOZERO)
        self.showImage(img)

        returnData = pytesseract.image_to_string(img,lang='eng',config='-psm 13 ' )
        returnData = ''.join(p for p in returnData if p.isnumeric() or p == ".") # REMOVE $ SIGN

回答1:

Before throwing the image into Pytesseract, some preprocessing to clean/smooth the image helps. Here's a simple approach

Convert image to grayscale and enlarge image
Threshold
Perform morphological operations to clean image
Invert image

First we convert the image to grayscale, resize using the imutils library then threshold to obtain a binary image

Now we perform morphological transformations to smooth the image

Now we invert the image for Pytesseract and add a Gaussian blur

We use the --psm 10 config flag since we want to treat the image as a single character. Here's some additional configuration flags that could be useful

Results

$2.10

After filtering

2.10

import cv2
import pytesseract
import imutils

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

image = cv2.imread('1.png',0)
image = imutils.resize(image, width=300)
thresh = cv2.threshold(image, 150, 255, cv2.THRESH_BINARY_INV)[1]

kernel = cv2.getStructuringElement(cv2.MORPH_ELLIPSE, (3,3))
close = cv2.morphologyEx(thresh, cv2.MORPH_CLOSE, kernel)

result = 255 - close 
result = cv2.GaussianBlur(result, (5,5), 0)

data = pytesseract.image_to_string(result, lang='eng',config='--psm 10 ')
processed_data = ''.join(char for char in data if char.isnumeric() or char == '.')
print(data)
print(processed_data)

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

来源：https://stackoverflow.com/questions/57480469/how-to-extract-decimal-in-image-with-pytesseract

标签

python

OpenCV

image-processing

computer-vision

python-tesseract