GraphicsMagick1.3.25安装

1. 安装相关依赖包

yum install -y gcc libpng libjpeg libpng-devel libjpeg-devel ghostscript libtiff libtiff-devel freetype freetype-devel

1. 下载GraphicsMagick

wget ftp://ftp.graphicsmagick.org/pub/GraphicsMagick/1.3/GraphicsMagick-1.3.25.tar.gz

1. 解压GraphicsMagick

tar -zxvf GraphicsMagick-1.3.25.tar.gz

1. 编译安装

cd GraphicsMagick-1.3.25
./configure
make && make install

1. 验证安装

gm version

输出一下信息说明安装成功

GraphicsMagick 1.3.21 2015-02-28 Q8 http://www.GraphicsMagick.org/
Copyright (C) 2002-2014 GraphicsMagick Group.
Additional copyrights and licenses apply to this software.
See http://www.GraphicsMagick.org/www/Copyright.html for details.

Feature Support:
  Native Thread Safe       yes
  Large Files (> 32 bit)   yes
  Large Memory (> 32 bit)  yes
  BZIP                     no
  DPS                      no
  FlashPix                 no
  FreeType                 yes
  Ghostscript (Library)    no
  JBIG                     no
  JPEG-2000                no
  JPEG                     yes
  Little CMS               no
  Loadable Modules         no
  OpenMP                   yes (201107)
  PNG                      yes
  TIFF                     yes
  TRIO                     no
  UMEM                     no
  WebP                     no
  WMF                      no
  X11                      no
  XML                      no
  ZLIB                     yes

Host type: x86_64-unknown-linux-gnu

Configured using the command:
  ./configure 

Final Build Parameters:
  CC       = gcc -std=gnu99
  CFLAGS   = -fopenmp -g -O2 -Wall -pthread
  CPPFLAGS = -I/usr/include/freetype2
  CXX      = g++
  CXXFLAGS = -pthread
  LDFLAGS  = -L/usr/lib
  LIBS     = -ltiff -lfreetype -ljpeg -lpng15 -lz -lm -lgomp -lpthread

OK，至此，GraphicsMagick安装完成。

Tesseract-OCR4.0.0 的安装

1. 依赖安装

yum install -y autoconf automake libtool libjpeg libpng libtiff zlib libjpeg-devel libpng-devel libtiff-devel zlib-devel

1. 下载安装Leptonica

wget http://www.leptonica.org/source/leptonica-1.77.0.tar.gz
tar -zxvf leptonica-1.77.0.tar.gz
cd leptonica-1.77.0
./configure
make && make install

1. 下载安装Tesseract-OCR

wget https://github.com/tesseract-ocr/tesseract/archive/4.0.0.tar.gz
tar -zxvf 4.0.0.tar.gz
./autogen.sh
./configure --with-extra-includes=/usr/local/include --with-extra-libraries=/usr/local/include
make && make install

这里./configure 会提示错误

error: Leptonica 1.74 or higher is required. Try to install libleptonica-dev package"

解决办法如下:

vi /etc/profile把下面配置添加到最后

export LD_LIBRARY_PATH=$LD_LIBRARY_PAYT:/usr/local/lib
export LIBLEPT_HEADERSDIR=/usr/local/include
export PKG_CONFIG_PATH=/usr/local/lib/pkgconfig

再执行source /etc/profile命令，让配置立即生效
之后再

 ./configure --with-extra-includes=/usr/local/include --with-extra-libraries=/usr/local/include
make && make install

1. 检测Tesseract-OCR 支持的语言
   cd 到Tesseract-OCR 指令安装目录：/usr/local/bin/tesseract
   github下载全套tessdata_fast并上传至/usr/local/share/文件夹下，将tessdata_fast改名为tessdata，(建议下载需要的语言包：eng.traineddata、chi_sim.traineddata)
   github链接

2. 验证安装，出现类似如下表示安装成功

tesseract -v

tesseract 4.00.00alpha
 leptonica-1.77.1
  libgif 4.1.6(?) : libjpeg 8d (libjpeg-turbo 1.5.0) : libpng 1.6.20 : libtiff 4.0.6 : zlib 1.2.8 : libwebp 0.4.3 : libopenjp2 2.1.0

至此 安装完成

记录下在node下使用的过程

下载两个npm包

npm install gm
npm install node-tesr

代码:

gm(imgPath)
    .threshold(62,true)
     .write(imgPath, (err) => {
        if(!err){
                tesseract(imgPath,{ l: 'eng', oem: 3, psm: 3 }, function(err, data) {
             // 此处获得识别内容
                   data = data.replace(/\s+/g,"");
                   console.log("识别到验证码:", data);
         })
    }
});