There's a very handy tool called pdftk that I use on linux. Try something like this:

This will convert a binary pdf into an uncompressed pdf that you can open in a text editor. The uncompressed one is still a valid pdf that can be opened in Adobe Reader, etc. As a test, you could just try hand-editing the file to see if the result is acceptable. If that works, then automating the process in perl should be pretty trivial.