为什么pytesseract不能识别个位数? [英] Why pytesseract does not recognise single digits?

问题描述

我正在一个网站上执行 ocr，特别是在这两个图像上:

我对 OCR 相当陌生，我使用以下内容:

from PIL 导入图片导入 pytesseractmy_image = '....png'文本 = pytesseract.image_to_string(Image.open(my_image))

在第二张图片中，它可以识别除单个数字 3、4、5、6 之外的所有内容.

在第一张图片中，它也无法识别单个数字.

我通过调整图像大小、反转它们和使用阈值来预处理图像.

这是一种标准字体，所以我知道还有其他方法可以做到这一点，但在一定程度上它对我有用，所以我想在进行更高级的事情之前保持简单.

解决方案

对于这两个图像，你可以

1. 对图像进行上采样:为了准确识别.
2. 应用

   结果将是:

   6200133000

   代码:

   ---

   导入 cv2导入 pytesseractimg1 = cv2.imread("lNKH4.png") # "FX2in.png";gry1 = cv2.cvtColor(img1, cv2.COLOR_BGR2GRAY)(h, w) = gry1.shape[:2]gry1 = cv2.resize(gry1, (w*2, h*2))gry1 = gry1[30:(h*2), w+50:w*2]thr1 = cv2.threshold(gry1, 0, 255, cv2.THRESH_BINARY_INV + cv2.THRESH_OTSU)[1]txt1 = pytesseract.image_to_string(thr1, config="--psm 6 位数字")打印(txt1)cv2.imshow(thr1", thr1)cv2.waitKey(0)

   对于第二张图片:

   结果将是:

   23 1.28 4.50 9.004 2.00 3.75 3.005 3.50 4.33 1.726 7.00 6.00 1.28

   相同的代码，只需删除以下行:

   gry1 = gry1[30:(h*2), w+50:w*2]

   I am performing ocr on a site and specifically on these two images:

   I am fairly new to OCR, I use the following:

   from PIL import Image
   import pytesseract
   
   my_image = '....png'
   text = pytesseract.image_to_string(Image.open(my_image))
   

   In the second image it recognises everything except the single digits 3, 4, 5, 6.

   In the first image it does not recognises the single digits too.

   I preprocess the images by resizing them, inverting them and using threshold.

   It's a standard font so I know there are other ways to do this, but until a certain degree it works for me, so I want to keep it simple before going to something more advanced.

   解决方案

   For the both image, you can

   1. upsample the image : For accurate recognition.
   2. apply simple-thresholding: To display the features.

   For the first image, you can take part of the image selecting a range:

   Result will be:

   62001
   33000
   

   Code:

   ---

   import cv2
   import pytesseract
   
   img1 = cv2.imread("lNKH4.png")  # "FX2in.png"
   gry1 = cv2.cvtColor(img1, cv2.COLOR_BGR2GRAY)
   (h, w) = gry1.shape[:2]
   gry1 = cv2.resize(gry1, (w*2, h*2))
   gry1 = gry1[30:(h*2), w+50:w*2]
   thr1 = cv2.threshold(gry1, 0, 255, cv2.THRESH_BINARY_INV + cv2.THRESH_OTSU)[1]
   txt1 = pytesseract.image_to_string(thr1, config="--psm 6 digits")
   print(txt1)
   cv2.imshow("thr1", thr1)
   cv2.waitKey(0)
   

   For the 2nd image:

   Result will be:

   2
   3 1.28 4.50 9.00
   4 2.00 3.75 3.00
   5 3.50 4.33 1.72
   6 7.00 6.00 1.28
   

   Same code, just remove the following line:

   gry1 = gry1[30:(h*2), w+50:w*2]
   

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