That is because jasper/libjasper is not part of Debian Stretch.
https://packages.debian.org/search?suit ... rds=jasper
BTW: Are we talking about jasper the Jpeg2000 decoding library (http://www.ece.uvic.ca/~frodo/jasper/
) or Jasper the voice-controll service (https://jasperproject.github.io/
EDIT: Since it was in conjunction with installing OpenCV I guess we are talking about the Jpeg2000 library. Try to disable support for it while configuring OpenCV, I cant imagine its a vital library.