Disk Utility to create disc image?

Hey everyone

I'm not too familiar with disk images, however my main goal is to capture the best quality video from a normal video dvd and then edit that video in final cut. I was told that possibly burning the disc and making a disk image would be the best way. If anyone can tell me the best way to capture video from a dvd (most likely copyrighted) to be edited in final cut I'd greatly appreciate it. If anyone is wondering I have a school assignment where I need to make a new trailer for a movie of my choice.

Thanks!