Look up coyote rollers. You can make your own using PVC pipe.
She does not have a collar. I was just making the assumption that she would need to wear something. Unless there is a way to just make the fence make a sound if something touches it.You say "the collar", is she wearing a shock collar?
For some dogs, a vibrating electronic collar can be as disturbing as the jolt of an electrical shock. That does not make the shock lessor, but rather that vibrate can be more than expected.
What is the interior surface of the fence? Block, wood or vinyl with rails on the outside, with rails on the inside? Type and size of dog?
You can work on boundary training with markers and rewards, I think on youtube both kikopup and zac george have some suitable videos.
Depending on your town rules and/or HOA rules, you could add a lattice work topper to a wood privacy fence or an open block topper to a block fence which adds height but not stopping light.