Ray might want to check out a group called Rollscanners which has about
100 members.  The group has been working on this problem for many
months.  Several of the members have done extensive roll scanning and
have made major contributions to the process.  It is on Yahoo at
http://groups.yahoo.com/group/Rollscanners/

Craig Smith
USA, New York State, Near Rochester and Lake Ontario,
Town of Pittsford, Have a cat, no snow yet!