I have installed the ros2 foxy fitzroy base package in my raspberry pi 4B running ubuntu server o20.04. Right now i'm trying to build the realsense D415 ros2 package in it following this link. But when i'm trying to buil this package using colcon built. i'm getting the error as:

  Could not find a package configuration file provided by "OpenCV" with any
  of the following names:

    OpenCVConfig.cmake
    opencv-config.cmake

So it looks like the ros2 foxy base packae is missing the opencv library. How do i add it?