Integrate OpenCV using cmake - cannot open shared object file - c++

Question

I am trying to integrate OpenCV (v4.1.2) into an existing project and I made below changes for that:
CMakeLists.txt
find_package(OpenCV REQUIRED core imgcodecs imgproc PATHS <path to all opencv shared object files>)
target_link_libraries(<exec name> ${OpenCV_LIBS})
Also added below to the config file:
#cmakedefine HAVE_LIBOPENCV 1
#cmakedefine HAVE_OPENCV_H 1
Copy the output executable at:
/usr/bin
Run the below command to set rpath:
patchelf --set-rpath path-to-opencv/opencv/lib:$ORIGIN /usr/bin/executablename
Below are the changes I added in the source code:
#include <opencv2/core.hpp>
#include <opencv2/imgcodecs.hpp>
cv::Mat img = cv::imread("sample.jpg", ZM_MAX_IMAGE_COLOURS);
cv::imwrite("sample-opencv.jpg", img);
However, when I run the the code, I see below message in logs:
error while loading shared libraries: libopencv_imgproc.so.4.1: cannot open shared object file: No such file or directory
Below are some sanity checks I performed on the executable file:
$readelf -d <executable name>
0x0000000000000001 (NEEDED) Shared library: [libopencv_imgcodecs.so.4.1]
0x0000000000000001 (NEEDED) Shared library: [libopencv_core.so.4.1]
0x000000000000001d (RUNPATH) Library runpath: [<path to opencv>/opencv/lib:]
$ ldd <executable name>
libopencv_imgcodecs.so.4.1 => <path to opencv>/opencv/lib/libopencv_imgcodecs.so.4.1 (0x00007f49cf6f9000)
libopencv_core.so.4.1 => <path to opencv>/opencv/lib/libopencv_core.so.4.1 (0x00007f49ce4fc000)
libopencv_imgproc.so.4.1 => <path to opencv>/opencv/lib/libopencv_imgproc.so.4.1 (0x00007f49c3b12000)
Even though there is a valid link in ldd output, libopencv_imgproc.so doesn't exist in readelf output. My assumption is that since there is no source code directly consuming imgproc, it doesn't show up in readelf output.
Can someone point out what is causing the "cannot open shared object file" error?
EDIT:
I changed my above code to include imgproc header and declare a class below as shown below:
#include <opencv2/core.hpp>
#include <opencv2/imgcodecs.hpp>
#include <opencv2/imgproc.hpp>
cv::Subdiv2D div; // comes from imgproc
cv::Mat img = cv::imread("sample.jpg", ZM_MAX_IMAGE_COLOURS);
cv::imwrite("sample-opencv.jpg", img);
It worked after this change. Also, below is the new readelf output:
$ readelf -d <executable name>
0x0000000000000001 (NEEDED) Shared library: [libopencv_imgcodecs.so.4.1]
0x0000000000000001 (NEEDED) Shared library: [libopencv_imgproc.so.4.1]
0x0000000000000001 (NEEDED) Shared library: [libopencv_core.so.4.1]
0x000000000000001d (RUNPATH) Library runpath: [<path to opencv>/opencv/lib:]
However, it is just a workaround. One shouldn't need to write a placeholder code like this. Can someone help figure out a clean solution to include shared objects correctly?
FYI - Here are the internal dependecies between these opencv shared objects:
libopencv_core --> no dependency
libopencv_imgproc --> libopencv_core
libopencv_imcodecs --> libopencv_core and libopencv_imgproc