Bug 465832

Summary: Recognize faces don't run because "there are no identities to recognize"
Product: [Applications] digikam Reporter: mahikeulbody <51mfxqck>
Component: Faces-WorkflowAssignee: Digikam Developers <digikam-bugs-null>
Status: RESOLVED WORKSFORME    
Severity: normal CC: metzpinguin
Priority: NOR    
Version First Reported In: 8.0.0   
Target Milestone: ---   
Platform: Manjaro   
OS: Linux   
Latest Commit: Version Fixed/Implemented In: 8.0.0
Sentry Crash Report:

Description mahikeulbody 2023-02-16 13:00:41 UTC 
SUMMARY
After a clean install of Digikam, it scans all items of my collection and load all "people" face tags included in the files. At the end of the scan they are all listed into People.
But then if I want to "Recognize faces", it says "There are no identities to recognize". It seems the database of "face characteristics" (I don't know the correct name) has not been fulfilled during the scan.

STEPS TO REPRODUCE
1. Clean install of Digikam (all related files deleted)
2. Run it with a collection including files with face metadata (mwg and subject) and some files without face metadata (but with "known" faces)
3. Run a "Recognize faces"

OBSERVED RESULT
After step 2 : all face tags are created into People (it is right)
After step 3 : message "there are no identities to recognize" (I need to re-train the face recognition for each faces)

EXPECTED RESULT
New occurrences of known faces (i.e. which exists into People) recognized.

ADDITIONAL INFORMATION
I am pretty sure there was no need to re-train the Face Recognition in the previous version after the initial scan.
Comment 1 Maik Qualmann 2023-02-16 13:35:43 UTC 
It has definitely always been necessary in such a case that the training database has to be rebuilt. Due to performance, this will not be done on item scanner.

Maik
Comment 2 Maik Qualmann 2023-02-16 13:38:26 UTC 
There is a corresponding function in the maintenance tool for rebuilding the training database from the confirmed faces.

https://docs.digikam.org/en/maintenance_tools/maintenance_faces.html

Maik
Comment 3 mahikeulbody 2023-02-16 15:32:09 UTC 
(In reply to Maik Qualmann from comment #2)
> There is a corresponding function in the maintenance tool for rebuilding the training database from the confirmed faces.
> 
> https://docs.digikam.org/en/maintenance_tools/maintenance_faces.html

Ok. It seems this tool will DETECT and recognize faces. I am afraid to have new detections of already detected faces, but with a different square. I had duplicated squares for the same faces in the past. Is it the case even with 
"Clear and rebuild data" set ?
Comment 4 Maik Qualmann 2023-02-16 18:03:23 UTC 
If you tick the i"Clear and rebuild data" set ? , the other settings are greyed out, i.e. not executed. Only the fingerprints (I just call them that) are created together with the name in the face database. This can be done anytime or should be done every once in a while if faces are mismatched etc. to have better face recognition. No face rectangles are created or anything like that.

Maik
Comment 5 mahikeulbody 2023-02-16 18:10:34 UTC 
(In reply to Maik Qualmann from comment #4)
> If you tick the i"Clear and rebuild data" set ? , the other settings are
> greyed out, i.e. not executed. Only the fingerprints (I just call them that)
> are created together with the name in the face database. This can be done
> anytime or should be done every once in a while if faces are mismatched etc.
> to have better face recognition. No face rectangles are created or anything
> like that.
> 
> Maik

Fine ! I am running that now.