/usr/share/doc/libopencv-imgproc2.4v5/changelog.Debian.gz is in libopencv-imgproc2.4v5 2.4.9.1+dfsg-1.5ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/libopencv-imgproc2.4v5/../libopencv-core2.4v5/changelog.Debian.gz