CentOS7 上编译安装 Tesseract 5.2.0

1、编译工具安装

yum install -y gcc gcc-c++ make autoconf automake libtool libjpeg libpng libtiff zlib libjpeg-devel libpng-devel libtiff-devel zlib-devel

2、升级gcc8（编译 Tesseract5 需要 c++17）

yum install -y centos-release-scl
yum install -y devtoolset-8-gcc*
mv /usr/bin/gcc /usr/bin/gcc-4.8.5
ln -s /opt/rh/devtoolset-8/root/bin/gcc /usr/bin/gcc
mv /usr/bin/g++ /usr/bin/g++-4.8.5
ln -s /opt/rh/devtoolset-8/root/bin/g++ /usr/bin/g++

查看版本是否安装成功

gcc -v
gcc (GCC) 8.3.1 20190311 (Red Hat 8.3.1-3)
g++ -v
g++ (GCC) 8.3.1 20190311 (Red Hat 8.3.1-3)

3、安装 leptonica（Tesseract 依赖 leptonica 进行图片处理）

wget http://www.leptonica.org/source/leptonica-1.82.0.tar.gz
tar zxf leptonica-1.82.0.tar.gz
cd leptonica-1.82.0/
./configure && make && make install

编辑 /etc/profile 添加环境变量

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

使配置失效

source /etc/profile

4、编译安装 tesseract 5.2.0

wget https://github.com/tesseract-ocr/tesseract/archive/refs/tags/5.2.0.tar.gz
tar xvf 5.2.0.tar.gz
cd tesseract-5.2.0
./autogen.sh
./configure --with-extra-includes=/usr/local/include --with-extra-libraries=/usr/local/lib
sudo make && make install

完成后提示：

Libraries have been installed in:
/usr/local/lib
If you ever happen to want to link against installed libraries
in a given directory, LIBDIR, you must either use libtool, and
specify the full pathname of the library, or use the `-LLIBDIR’
flag during linking and do at least one of the following:add LIBDIR to the `LD_LIBRARY_PATH’ environment variable
during executionadd LIBDIR to the `LD_RUN_PATH’ environment variable
during linkinguse the `-Wl,-rpath -Wl,LIBDIR’ linker flaghave your system administrator add LIBDIR to `/etc/ld.so.conf’

完成后查看版本

​​tesseract -v

5、下载语言

cd /usr/local/share/tessdata/
wget https://github.com/tesseract-ocr/tessdata/raw/main/eng.traineddata
#这里下载的是 legacy 英文语言模型，也可以下载 fast 或 best 的

6、测试

tesseract 25.png output

执行后 output.txt 中就是 ocr 结果

来源：http://devgou.com/article/Tesseract/