rescan for faces in photos

Unfortunately, photos in High Sierra is a terrible update when it comes to face recognition. The older versions (both Photos and iPhotos) would auto-detect 99% of faces (with a few mistakes, power sockets, statues, etc.). It would then take 10 minutes to add the names and merge a few together. Job-done.

The new Photos recognises about 80% of faces, but only shows them in the 'people' tab if it finds 15 or more photos of what it thinks is the same person. I just don't have that many photos of all my friends and family! I can see this setting in a file called "faceWorkerState.plist" but when I change it, some process just changes it back.

I've managed to get something approaching a full library of people by making 16 duplicates of the entire library and letting Photos wade through that for a week, then spending the 10 minutes as above to add names and merge. Then deleting the duplicates. The whole process takes about 2 weeks with a library of 3K photos.

A complete pain in the rear to restore functionality that worked pretty well just one version ago.

P.S. Photos does NOT scan 'exactly once'. It still scans on EVERY device you have. Sometimes an iOS scan will turn up photos that a MacBook scan missed!! When a device finishes scanning it then seems to merge the results together in a master DB.

Same here! Also if Photos doesn't think it's the same person or doesn't recognise it as a face you'll need considerably more than 15. I have 20ish photos of my mum over a 30 year period that Photos thinks is 4 different people

The config's in this file

~/Pictures/Photos Library.photoslibrary/private/com.apple.photoanalysisd/VisionService/faceWorker State.plist

~ is unix shorthand for your user's home directory

'Photos Library.photoslibrary' is the default name of the photos library - you might have a different name

parameter name is PersonBuilderLastMinimumFaceGroupSizeForCreatingMergeCandidates

There's no documentation so there's a bit of guesswork involved, but in my experiments

1. Wait for the initial image scan to finish. Choose someone who's in a few photos but no photo of person is in the persons tab. Tell Photos the name of this person (in a single image click 'unnamed' below the face and type the name) and it immediately adds it to the persons tab along with several other photos of this person. It didn't have time to scan the library again, it had already associated the group but it wasn't big enough. I've see this happen with 10 photos at once.

2. Find a photo of someone who is not recognised in the persons tab. Make a duplicate of the photo Then do it again, and again and eventually that person will pop up in the persons tab! You can then set the correct name and safely delete the duplicates. NOTE - it only works if Photos has established this is a face. If it doesn't show 'unnamed' then this trick doesn't work

The album of all unidentified faces is no longer there. Photos will at first only add a few faces to the People album to get you started, faces of people that are occurring frequently in your photos.

If you want to add an additional person, start from a photo showing this person. Just type a name into the text field below the circle around a face and it will add a new person to the People album.

• Click a photo, to view it enlarged.
• If Photos found a face or you added a face manually, you will see a circle around the detected face.

The circles will only show, if you enable "Show faces names" in the "View" menu. You can switch them off again, with "Hide Faces Names", to be able to see the photo properly.

To name further faces of the same person, open the album that has been added and click "Confirm additional faces".

~/Pictures/Photos Library.photoslibrary/private/com.apple.photoanalysisd/VisionService/faceWorker State.plist

Yes, thank you, I found that entry inside my Photos Library.

It seems to be used by the com.apple.photoanalysisd process or some sub process.

When I manually change the value of PersonBuilderLastMinimumFaceGroupSizeForCreatingMergeCandidates to a lower number using Xcode and restart my Mac, something strange happens. I am suddenly seeing again

I tried to change the entry also by using the defaults command from the Terminal, but that does not seem to work for subprocesses of Photos:

defaults write photoanalysisd.apple.com. PersonBuilderLastMinimumFaceGroupSizeForCreatingMergeCandidates 5

My photos library is too large to try the duplication method - that is a brilliant workaround!

defaults write com.apple.photoanalysisd PersonBuilderLastMinimumFaceGroupSizeForCreatingMergeCandidates 5

It writes it, but I don't know if it'll do anything yet - about to restart now

The new Photos recognises about 80% of faces, but only shows them in the 'people' tab if it finds 15 or more photos of what it thinks is the same person.

That is really interesting. Where did you find the number of at least 15 recognized faces?

Do you mean there is a hidden default for the limit in"faceWorkerState.plist" or does this file describe the numbers of recognized faces?

That is ridiculously high. For most people in my library, even for friends and family I have no more that five photos in my library.

I hope there is a way to force a rescan that is less effort than moving around 50GB of data.

No as Léonie answered (very clearly IMHO)

Photos will scan all photos for faces exactly once

For feature requests tell Apple what you want - Product Feedback - Apple

LN

Since upgrading to High Sierra, there is no "Add +" button anymore in the People view in Photos, at least not on my laptop. Not sure where the unidentified faces are and how to access them.

btw - thanks for the nice words, but it's a horrible dirty workaround. Would be great if we can get something more elegant with your defaults write idea. :-)

I recently downloaded all my high resolution photos to my iMac and would like to have it rescan for faces and prompt me for the name.

Photos will scan all photos for faces exactly once - when you first import them to photos.This scanning happens in the background and only, when you are not using Photos.

You will see all newly recognized faces in Photos, if you open the People album and click the "Add +" button at the bottom of the People album. This will let you select recognized faces to add to the People Album and to name.

Or click the album of a named person to ope it. If Photos has found additional faces of the person, it will prompt you to confirm them.

This I have read; however many of my photos have unrecognized faces in them. Clear and easy to identify. Previously iPhoto would rescan and find most of the missing faces.

Are you sure that Photos has already finished the faces scan?

For 50k photos it can take several weeks to complete the initial scan.

You could wait for the High Sierra upgrade. That will change and improve the face recognition algorithm again and may detect more faces than already have been recognized.