Reason: when a face is removed from a previously indexed image it is not possible to automatically recognize faces other than reviewing many images and manually applying a face region.
See this forum discussion: https://forums.adobe.com/message/7472...
If you flip your images horizontally, you can get LR to start indexing again, and it does find some missing images. When it has finished just flip them all back again. The faces flip back as well.
But to re-index a folder from scratch again, perhaps because like me you have accidentally deleted some faces, is more complicated. It can be done as I've just done it on a folder of 6000 images, part of a 100K catalog.
Step 1 is to backup the catalog, twice if you are of a nervous disposition!
Step 2 is to select the images in the folder you want to re-index from scratch, and export them to a new catalog (without originals or previews - you just want the data in the catalog)
Step 3 is to download a browser that allows you to look at and edit tables in the catalog. I use DB browser for SQLite < https://github.com/sqlitebrowser/sqlitebrowser/releases>
Step 4 is to open the new catalog containing the images to be re-indexed with the browser (NOT with LR ).
Step 5 is to find the tables in the browser that pertain to face recognition. I found four containing face info
Step 6 is to delete all the lines of info in these tables. Just select all the lines in a table in the usual way and then click on delete at top right. Repeat with the other face tables
Step 7 is to save the edited catalog without the face info, and exit the browser.
Step 8 is to open LR with your main catalog, and remove the contents of the folder you are about to reimage. Remove the files from the catalog, NOT from the disk. This process can take some time. I watched it using the Performance monitor in win10, because although deleting the images from the catalog is more or less instant, deleting the previews is a more lengthy affair which seems to occur when LR feels like it.
Step 9 is to import the images from the edited catalog without face info back into your main catalog, where they will replace the ones you have just removed that had face info.
Step 10 is to tell LR to make new previews for these imported images (all your editing data is still there - you have not lost it), and then to start face recognition on this folder.
I have just done this and all my faces of named and unnamed people are now back; the main catalog passes the LR integrity test and I'm now back where I was yesterday before I accidentally removed all those faces.
It would of course be easier if Adobe coded this for us!
I imported 100K photos and Lightroom CC crashed half way through the face recognition. Now I can't get it to re-scan the the appropriate folders to fix this. Vary frustrating.
I accidentally removed a large set of face regions (an entire person) when trying to clean things up (because there are so many poor matches in face recognition). Because my mouse clicks / keyboard commands were lagging behind by 15-30 seconds depending on what I was doing (I have a lot of pictures but clearly Lightroom has performance issues), I apparently removed a "person" that I REALLY want back. This particular person (the face regions identified for this person) was found around 8000 times in my photos (that I spent hours assigning and correcting the face assignments) and now it shows 35. I clearly multi-selected a huge amount of face regions that I shouldn't have (again, LR was processing my commands with a 15-30 second lag time). I want to undo this (but I'm not sure how it happened and it is no longer in my undo queue.
PLEASE ADOBE... I WANT TO RESCAN A SET OF FOLDERS TO GET THIS PERSON BACK!!! THERE IS NO WAY I AM DRAWING 8000 FACE REGIONS MANUALLY. That's really not a "workaround".
Adobe - I get it. I screwed up. But Lightroom isn't really making it easy for me and I can't seem to fix this.
Can someone from the Lightroom team simply reply to this thread so everyone isn't left in the dark feeling like we are being completely ignored? Just a bit of customer service would be greatly appreciated.
Come on Adobe, you can do it!
Whats the point of Adobe putting automatic facial recognition as an option in a program when you can't rerun it on a set of photos?
Adobe seems to be recommending that we all get RSI (Repetitive Strain Injury) by manually selecting each photo and individually tagging them :-(
This version of Lightroom contains a much improved face engine and the ability to re-index photos for faces. See
https://helpx.adobe.com/lightroom/help/face-recognition.html#find-faces-again for details.
The community has been requesting a rescan faces feature for 4 years now... Can someone please comment on the timeline for this functionality?
If you are a people view user and want this feature, please support this thread and the original one located here: https://feedback.photoshop.com/photoshop_family/topics/lightroom-6-cc-allow-facial-recognition-featu...