0. 环境
1. 第一次出错
   1.1 make提示
   1.2 make报错
   1.3 尝试
   1.4 解决1
2. 第二次出错
   2.1 cmake报错
   2.2 解决

由于换电脑、重装系统、系统奔溃、换固态，不到一年已经重装OpenCV不下十次了，本以为装了这么多次应该没什么问题了，可最奔溃的是几乎每次都会出错，而且出的错每次都不一样，心疼自己。。。把这次出现的问题记录一下。

0. 环境

ubuntu14.04
opencv3.3.1
opencv_contrib-3.3.1

1. 第一次出错

1.1 make提示

Failed to download tiny-dnn sources

-- Looking for tiny_dnn.h
-- Looking for tiny_dnn.h - not found
-- Module opencv_dnn_modern disabled because tiny-dnn was not found
-- checking for one of the modules 'freetype2'
-- checking for one of the modules 'harfbuzz'
-- freetype2: NO
-- harfbuzz: NO
-- Could NOT find HDF5 (missing: HDF5_LIBRARIES HDF5_INCLUDE_DIRS)
-- No preference for use of exported gflags CMake configuration set, and no hints for include/library directories provided. Defaulting to preferring an installed/exported gflags CMake configuration if available.
-- Failed to find installed gflags CMake configuration, searching for gflags build directories exported with CMake.
-- Failed to find gflags - Failed to find an installed/exported CMake configuration for gflags, will perform search for installed gflags components.
-- Failed to find gflags - Could not find gflags include directory, set GFLAGS_INCLUDE_DIR to directory containing gflags/gflags.h
-- Failed to find glog - Could not find glog include directory, set GLOG_INCLUDE_DIR to directory containing glog/logging.h
-- Module opencv_sfm disabled because the following dependencies are not found: Eigen Glog/Gflags
-- checking for modules 'tesseract;lept'
-- package 'tesseract' not found
-- package 'lept' not found
-- Tesseract: NO
-- xfeatures2d/boostdesc: Download: boostdesc_bgm.i
CMake Warning at ~/workspace/opencv/opencv-master/cmake/OpenCVDownload.cmake:170 (message):
xfeatures2d/boostdesc: Download failed: 1;"Unsupported protocol"
Call Stack (most recent call first):
~/workspace/opencv_contrib-master/modules/xfeatures2d/cmake/download_boostdesc.cmake:22 (ocv_download)
~/workspace/opencv_contrib-master/modules/xfeatures2d/CMakeLists.txt:8 (download_boost_descriptors)12345678910111213141516171819202122232425

1.2 make报错

In file included from ~/workspace/opencv/opencv-master/modules/stitching/include/opencv2/stitching.hpp:49:0,
from ~/workspace/opencv/opencv-master/modules/stitching/src/precomp.hpp:59,
from ~/workspace/build/modules/stitching/opencv_stitching_pch_dephelp.cxx:1:
~/workspace/opencv/opencv-master/modules/stitching/include/opencv2/stitching/detail/matchers.hpp:52:42: fatal error: opencv2/xfeatures2d/cuda.hpp: No such file or directory
# include "opencv2/xfeatures2d/cuda.hpp"
^123456

1.3 尝试

①看了cmake时的提示，估计是opencv_contrib-3.3.1/modules/dnn_modern 中文件下载出错，于是参考网上的方法离线下载放入对应的路径中，但还是没有解决。又怀疑是网络问题更换了国外的源，并启用了代理，也是没有下载成功。

②又根据make时报错的提示，想可能时cuda的因素，尝试不启用也没有解决。

1.4 解决1

cmake过程中会下载很多需要的文件，没有下载成功也不会报错，所以没注意的话一般就直接执行下一步了，然后make时报错，通常根据make时的提示寻找问题，但其实根源是在cmake时出现的，所以先解决cmake的问题。

参考github上的issue：https://github.com/opencv/opencv_contrib/issues/1131
有网友根据提示Download failed: 1;"unsupported protocol"认为是因为下载出错引起的，所用的cmake版本没有支持HTTPS，于是重新安装了cmake（之前用的时3.11版本，然后卸载按下面的方式安装了3.9.0）

wget --no-check-certificate https://cmake.org/files/v3.9/cmake-3.9.0.tar.gz
tar -zxvf cmake-3.9.0.tar.gz
cd cmake-3.9.0
sudo apt-get install libcurl4-gnutls-dev
sudo apt-get install zlib1g-dev
./bootstrap --system-curl
sudo make && sudo make install1234567

安装完之后然后重新cmake，cmake两遍看出现的问题2（第一遍出错时信息太多，没显示出错的地方，cmake第二遍）
（安装支持HTTPS的cmake不是直接解决问题，而是可以更清楚地看问题的根源）

2. 第二次出错

2.1 cmake报错

Invalid escape sequence \,
Call Stack (most recent call first):
/home/tank/Programming/opencv/cmake/OpenCVDownload.cmake:162 (ocv_download_log)
/home/tank/Programming/opencv_contrib/modules/xfeatures2d/cmake/download_boostdesc.cmake:22 (ocv_download)
/home/tank/Programming/opencv_contrib/modules/xfeatures2d/CMakeLists.txt:8 (download_boost_descriptors)

-- Configuring incomplete, errors occurred!
See also "/home/tank/Programming/opencv/build/CMakeFiles/CMakeOutput.log".
See also "/home/tank/Programming/opencv/build/CMakeFiles/CMakeError.log".12345678910

2.2 解决

Github上有网友指出是因为OpenCVDownload.cmake在日志记录功能中出现问题，找到文件～/opencv-3.3.1/cmake/OpenCVDownload.cmake
将以下代码

macro(ocv_download_log)
file(APPEND "${OPENCV_DOWNLOAD_LOG}" "${ARGN}\n")
endmacro()123

修改成

function(ocv_download_log)
file(APPEND "${OPENCV_DOWNLOAD_LOG}" "${ARGN}\n")
endfunction()123

然后重新cmake，make，make install 成功。

————————————————
版权声明：本文为CSDN博主「五小郎的学习笔记」的原创文章，遵循 CC 4.0 BY-SA 版权协议，转载请附上原文出处链接及本声明。
原文链接：https://blog.csdn.net/wuyanmin1995/java/article/details/81060991