CMake Error at CMakeLists.txt:5 (find_package):
By not providing "FindSophus.cmake" in CMAKE_MODULE_PATH this project has
asked CMake to find a package configuration file provided by "Sophus", but
CMake did not find one.
Could not find a package configuration file provided by "Sophus" with any
of the following names:
SophusConfig.cmake
sophus-config.cmake
Add the installation prefix of "Sophus" to CMAKE_PREFIX_PATH or set
"Sophus_DIR" to a directory containing one of the above files. If "Sophus"
provides a separate development package or SDK, be sure it has been
installed.
-- Configuring incomplete, errors occurred!
实际上是因为我从git上clone下来sophus后并没有编译，导致没有sophus，也就是没有安装sophus。
解决：
cd Sophus
cmake .
make
(sudo make install )