I've been developing Python code for dealing with .IMD files off and on. It's not complete by any stretch of imagination, but if you're comfortable with Python then you might be able to use it to do what you want:
https://github.com/NF6X/pyImageDisk At this time, extracting meaningful data would require more coding. Using the provided classes to pull out raw sector data would be easy, but it does not yet have any understanding of filesystems. I do play to add support for at least some filesystems in the future, but at this time the filesystem code is just some nonfunctional skeleton classes that I'm still working on. The provided command-line utility will at least reveal details about the low level format, such as sector sizes, interleave factors, use of different sector address marks (i.e., the use of DDAM marks on the directory track of some TRS-80 formats), or weird cylinder and head numbers in the headers. It'll also do hex dumps of the entire disk image or individual sectors. And it can change interleave factors and first sector after the index pulse if that might be helpful. -- Mark J. Blair, NF6X <n...@nf6x.net> http://www.nf6x.net/
