Assertion `px != 0′ failed
It has something to do with initialization issue. You need to initialize before you use shared_ptr.
- Before
pcl::PointCloud<pcl::PointXYZI>::Ptr input_cloud; // assertion failed
- After
pcl::PointCloud<pcl::PointXYZI>::Ptr input_cloud(new pcl::PointCloud<pcl::PointXYZI>());