Both the commands readom and dd can be used to rip (copy) optical media to an ISO image. readom is preferrable as it checks for errors on the fly, it is part of the wodim package.
Here are examples of both commands (replace /path/to/ with the target directory)
readom dev=/dev/sr0 f=/path/to/image.iso
dd if=/dev/sr0 of=/path/to/image.iso