1. Firstly, need to check which version pcl you need to install on your ubuntu system.
PCL download link:
https://github.com/PointCloudLibrary/pcl/releases?page=2https://github.com/PointCloudLibrary/pcl/releases?page=2
Then click Assets, and download the source code.zip
2. unzip source_code.zip
3. cd source_code
4.
mkdir build && cd build
5.
cmake ..
6.
make -j2 && sudo make install
7.
please enter into /usr/local/include
the pcl-1.9 can be found here.