如何使用djpeg和netpbm

1. 问题来源：

# Rescaling and intensity normalization
djpeg $infile | ppmtopgm | pnmnorm -bpercent=0.01 -wpercent=0.01 -maxexpand=400 | pamscale -pixels $[1024*768] > $tmpfile

2. 

下载 libjpeg

安装

./configure

make

sudo make install

遇到 ./configure: /bin/sh^M: bad interpreter: No such file or directory 问题

解决 vim 下:set fileformat=unix， 见./configure : /bin/sh^M : bad interpreter 第二个答案

3. 

下载 netpbm, 按照其ReadMe指示安装依赖包和安装

修改环境变量 export PATH=$PATH:/usr/local/netpbm/bin, export LD_LIBRARY_PATH=/usr/local/netpbm/lib, 并且export PATH=$PATH:/usr/local/netpbm/bin, export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/netpbm/lib加到～/.bashrc末尾 

如果出现symbol lookup error错误， 是因为库设置不对