The extraction of opium for alkaloids is well described by the literature. However, extraction of Papaver somniferum straw is at best vague, the following patents describe the process:
GB353069(1931)
GB406107(1934)
623,907 (1949) Hungary
GB623907(1947)
2,565,067(1951)US
GB713689(1952)
US6054584(2000)US6067749(2000)