Tesseract returns 如果出现未知字符，有时会出现空字符串

Question

我正在使用 Tesseract 检测白色背景的黑色文字。在某些图像中，黑色字后出现一个信息符号。我对检测这个符号不感兴趣，我只对这个词感兴趣。有时信息符号（周围有一个圆圈）被检测为 0 或 O，这很好。但在其他情况下（可能如果 tesseract 不知道如何处理这个符号）它只是返回一个空字符串，所以这个词也不会返回。我使用了给定的代码 here and also tried the configuration suggested

from PIL import Image
import pytesseract
import argparse
import cv2
import os
import numpy as np

# construct the argument parse and parse the arguments
ap = argparse.ArgumentParser()
ap.add_argument("-i", "--image", required=True,
    help="path to input image to be OCR'd")
ap.add_argument("-p", "--preprocess", type=str, default="thresh",
    help="type of preprocessing to be done")
args = vars(ap.parse_args())

# load the example image and convert it to grayscale
image = cv2.imread(args["image"])
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)

# check to see if we should apply thresholding to preprocess the
# image
if args["preprocess"] == "thresh":
    gray = cv2.threshold(gray, 0, 255,
        cv2.THRESH_BINARY | cv2.THRESH_OTSU)[1]

# make a check to see if median blurring should be done to remove
# noise
elif args["preprocess"] == "blur":
    gray = cv2.medianBlur(gray, 3)

# write the grayscale image to disk as a temporary file so we can
# apply OCR to it
filename = "{}.png".format(os.getpid())
cv2.imwrite(filename, gray)

# load the image as a PIL/Pillow image, apply OCR, and then delete
# the temporary file
text = pytesseract.image_to_string(gray, config='--psm 7')
os.remove(filename)
print("Output: " + text)

如果有人知道我还能做什么，我将不胜感激！

Answer 1

已解决：config 必须是 config='-psm 7'，只有一个“-”

Tesseract returns 如果出现未知字符，有时会出现空字符串

Tesseract returns sometimes an empty string if an unknown character occurs

python

tesseract

python-tesseract