ubuntu下安装opencv，cmake出错，解决方法

错误原因：
Make Error at 3rdparty/ippicv/downloader.cmake:75 (message):
  ICV: Failed to download ICV package: ippicv_linux_20140513.tgz.
  Status=28;"Timeout was reached"
Call Stack (most recent call first):
  3rdparty/ippicv/downloader.cmake:108 (_icv_downloader)
  cmake/OpenCVFindIPP.cmake:212 (include)
  cmake/OpenCVFindLibsPerf.cmake:12 (include)
  CMakeLists.txt:449 (include)


-- Configuring incomplete, errors occurred!answer:
。。。。。。。。。。。。。。CMakeOutput.log

linux安装opencv需要使用到的ippicv_linux_20141027.tgz安装包.Is it because OpenCV3.0 needs another version of ippicv? I understand that the error comes while downloading ippicv_linux_20140513.tgz (in the 3rd party, ippicv folder).

因为墙的原因一直下载不下来.

下载后拷贝到opencv/3rdparty/ippicv/downloads/linux-8b449a536a2157bcad08a2b9f266828b/ 目录下即可，如果没有该目录，则创建之。

将下载的文件 

~/opencv-3.0.0/3rdparty/ippicv/downloads/linux-8b449a536a2157bcad08a2b9f266828b ,代替原来的同名文件，ok问题解决。