How do you add external libraries to 'self-made' libraries using CMake? - c++

Question

I'm not able to link external libraries with the libraries I wrote using CMake. I'm wondering if there's something that is needed to be added to my CMakeLists.txt? Or if I need to add another CMakeLists.txt in a lower level (inside src) and what would that need to contain?
I have the following project structure:
ProjectFolder
│   ├── CMakeLists.txt
│   ├── build
│   │   └──
│   ├── include
│   │   └── helper.h
│   └── src
│   ├── helper.cpp
   └── main.cpp
My CMakeList.txt is:
cmake_minimum_required(VERSION 2.6 FATAL_ERROR)
project(object_detection)
find_package(PCL 1.5 REQUIRED)
find_package(OpenCV REQUIRED)
file(GLOB SOURCES src/*.cpp)
file(GLOB INCLUDE include/*.h)
include_directories(${PCL_INCLUDE_DIRS} ${INCLUDE})
link_directories(${PROJECT_NAME} ${PCL_LIBRARY_DIRS} ${SOURCES} )
add_definitions(${PCL_DEFINITIONS})
add_executable (${PROJECT_NAME} src/main.cpp)
target_link_libraries (${PROJECT_NAME} ${OpenCV_LIBS} ${PCL_LIBRARIES} ${SOURCES})
In my file helper.cpp I have:
#include <pcl/io/pcd_io.h>
Which gives the error:
fatal error: 'pcl/io/pcd_io.h' file not found
#include <pcl/io/pcd_io.h>
^~~~~~~~~~~~~~~~~
However I have the same include in main.cpp with no errors.
I would be very grateful for any help, please let me know if I need to clarify my question or error.
Thank you.

Answer 1

There are several errors in the CMakeLists.txt with the following changes the project loads appropriate libraries and builds properly. Another note is that before, to include helper.h I needed to write:
#include "../include/helper.h".
Now it works as expected with #include "helper.h".
Here is the modified CMakeLists.txt:
cmake_minimum_required(VERSION 2.6 FATAL_ERROR)
project(object_detection)
find_package(PCL 1.5 REQUIRED)
find_package(OpenCV REQUIRED)
file(GLOB SRC_FILES ${PROJECT_SOURCE_DIR}/src/*.cpp)
include_directories(${PCL_INCLUDE_DIRS} include)
link_directories(${PROJECT_NAME} ${PCL_LIBRARY_DIRS})
add_definitions(${PCL_DEFINITIONS})
#add_executable (${PROJECT_NAME} src/helper.cpp src/main.cpp )
add_executable (${PROJECT_NAME} ${SRC_FILES} )
target_link_libraries (object_detection ${PCL_LIBRARIES} ${OpenCV_LIBS})