Can Imatch find faces tagged with other applications?

[frlindla]

If a face is confirmed in an other application, will Imatch be able to detect that?

[bekesizl]

It will depend on the application used.
Mylio and IMatch work together very well in this respect.

IMatch sees faces confirmed in Mylio. But you have to take care in Mylio to "Save metadata to files" in case of JPG, TIF and DNG files (think of it as the write-back in IMatch, but without a notification for it).
IMatch than will want to rewrite the "PersonsInImage" tag.

Mylio also sees, if you face tag manually and write back to the files.

[frlindla]

Rewrite "PersonInImage" Tag - do you mean to rescan?

[bekesizl]

No. Rewrite means a write-back indicated by IMatch after rescanning the files.
It is needed, because Mylio doesn't write this tag.

[Mario]

IMatch can import face regions written by other XMP-compliant applications. See Using Google Picasa™ / Adobe Lightroom® Face Tags in IMatch for more information.
So, if your other application stores the information in the standard XMP face region format, the answer is yes.

The PersonInImage tag is a standard tag and should contain the 'names' (or similar attribute) of all the persons in the image.
See Faces and XMP Metadata in the IMatch help for more information.

Mylio seems to have only rather limited support for XMP (as far as I could figure out in a limited test by installing a demo a while ago and writing some metadata to see what the results are).
PersonsInImage is not maintained by them, among many other useful or even required fields. It also does seems to not import/map existing EXIF/legacy IPTC or all relevant GPS fields into the XMP record it maintains internally and thus the XMP record they produce is very 'basic'.
Metadata handling is probably not something Mylio prioritizes - like so many other consumer products out there.

[frlindla]

I discovered that Imatch picked up confirmed faces from Mylio, but not all faces... Maybe I have to force Imatch to rescan once more?

I also have to admit that no software I have tried comes close to Imatch when it comes to metadata handling. That is why I now use Imatch a lot for metadata. The map options in Imatch is also very good.

[Mario]

IMatch picks up all XMP face regions when it ingests a file. And then transforms them into face annotations, does the people/face recognition magic in the background etc.
Unless the file already has face annotations in the database. You can force a reload of the XMP face annotations by deleting existing face annotations (File Window command) and then doing a Forced rescan of the file with Shift+Ctrl+F5.

If some faces don't show up in IMatch, something may be wrong with the metadata in the file. Or maybe Mylio has not written all data (yet) or not all face data. Hard to tell without looking at the metadata of an actual file.

You can see all face regions in the file when you switch the Metadata Panel to the "Browser" layout. Then search for region.

[bekesizl]

I discovered that Imatch picked up confirmed faces from Mylio, but not all faces... Maybe I have to force Imatch to rescan once more?

Most probably a "Save metadata to file" in Mylio is missing.
Saving "Face regions" to the XMP file automatic there, but in case of JPG/TIF/DNG files, you have to execute this command manually (and there is no warning, that there are differences between the XMP file and image file metadata content).

I haven't seen this problem in my library. Most of my newer images are RAW+JPG pairs. There Mylio writes the face regions automatically to the XMP file and IMatch picks it up (and wants to save it right away to the JPG).