Extracting bar code label and overview image from MRXS slide

[Tom N.]

3DHistech scanners take grey scale image of the bar code label on the 
slide as well as of the glass slide. These images are embedded in the 
MRXS file. How would one go about extracting those images from the file 
using preferable VIPS or if not possible, using an available OpenSlide 
tool or API ?

Thank you very much.
Regards
Tom