barcode mobile vision can return the so-called "bounding box":
barcode.getBoundingBox()
bbox: (Rect)(356, 676, 721, 1034)
from there you can figure out where the barcode is in the image, and some
simple subtraction (right - left, bottom - top) will tell you how large the
barcode is (if that's of any particular use).
the so-called "cornerPoints" field should tell you the same thing. take a look
at both.
i don't know exactly how you're using mobile vision, so i'll leave it at that.