http://tenderlovemaking.com/2014/03/26/webcam-photos-with-ruby.html

av_server.rb

require 'av_capture'
require 'drb'

class PhotoServer
  attr_reader :worker

  def initialize
    @worker = Queue.new
  end

  def take_photo
    connection = @worker.pop
    connection.capture
  ensure
    @worker.push connection
  end
end

server = PhotoServer.new

Thread.new do
  session = AVCapture::Session.new
  dev = AVCapture.devices.find(&:video?)

  session.run_with(dev) do |connection|
    server.worker.push connection
    sleep
  end
end

URI = "druby://localhost:8787"
DRb.start_service(URI, server)
DRb.thread.join