How can I return a value from a thread in Ruby?

If I have the following code :

threads = []
(1..5).each do |i|
  threads << Thread.new { `process x#{i}.bin` } 
end
threads.each do |t|
  t.join
  # i'd like to get the output of the process command now.
end

What do I have to do to get the output of the process command? How could I create a custom thread so that I can accomplish this?