lua中require 'cv' 是指什么

ubuntu16.04 已经装有opencv3.1库，但是require 'cv' 提示没有cv模块，请问该怎么解决？谢谢 require 'cv'
/home/ubuntu/torch/install/share/lua/5.1/trepl/init.lua:389: module 'cv' not found:No LuaRocks module found for cv
    no field package.preload['cv']
    no file '/home/zzh/.luarocks/share/lua/5.1/cv.lua'
    no file '/home/zzh/.luarocks/share/lua/5.1/cv/init.lua'
    no file '/home/zzh/torch/install/share/lua/5.1/cv.lua'
    no file '/home/zzh/torch/install/share/lua/5.1/cv/init.lua'
    no file './cv.lua'
    no file '/home/zzh/torch/install/share/luajit-2.1.0-beta1/cv.lua'
    no file '/usr/local/share/lua/5.1/cv.lua'
    no file '/usr/local/share/lua/5.1/cv/init.lua'
    no file '/home/zzh/.luarocks/lib/lua/5.1/cv.so'
    no file '/home/zzh/torch/install/lib/lua/5.1/cv.so'
    no file '/home/zzh/torch/install/lib/cv.so'
    no file './cv.so'
    no file '/usr/local/lib/lua/5.1/cv.so'
    no file '/usr/local/lib/lua/5.1/loadall.so'
stack traceback: