初识OCR，Tesseract的安装与使用

1、安装 Tesseract

Ubuntu

sudo apt-get install tesseract-ocr

mac

brew install tesseract

win10

下载地址：

tesseract下载地址：https://digi.bib.uni-mannheim.de/tesseract/

下载最新的，下载后双击安装。安装完成后配置环境变量。

右键“此电脑”，选择“属性“->高级系统设置->环境变量->Path，双击Path，然后将tesseract的安装路径添加到Path中。

验证：

$ tesseract -v

测试：

$ tesseract example_03.png stdout digits

python调用

安装python版的tesseract

pip install pytesseract

安装完成后，还需要给pytesseract配置tesseract的环境变量。打开pytesseract的安装位置，我的是D:\ProgramData\Anaconda3\Lib\site-packages\pytesseract\pytesseract.py，将tesseract.exe的完整路径赋值给tesseract_cmd，如下图

然后测试

python代码：

# import the necessary packages
from PIL import Image
import pytesseract
import argparse
import cv2
import os
# 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(Image.open(filename))
os.remove(filename)
print(text)
# show the output images
cv2.imshow("Image", image)
cv2.imshow("Output", gray)
cv2.waitKey(0)

执行命令：

python ocr.py --image images/example_01.png

原图与二值化后的图：

输出结果：

代码：