# Ways to improve facial recognition



## Lessig (Sep 5, 2021)

I've seen (closed) threads about how good/bad the facial recognition is. I've found it to be terrible. I get mistaking my wife for her kid or parents. But I don't get mistaking her for this.






Can it be that the engine is really that bad? Is there some reset to get it to try again?


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## johnrellis (Sep 5, 2021)

Adobe doesn't have the depth and breadth of engineering talent that Google and Facebook have -- the economics of LR are much different than the huge social-media platforms.  Adobe licenses its face technology from a third party. In general, it's easy to do mediocre AI these days (lots of software from freshly minted PhDs), but very hard and expensive to do great AI.  (My background: leading companies in applying AI to search and advertising for 15 years.)





The basic face-detection algorithms that have been around for 20 years use surprisingly simple techniques -- they're looking for features that look like two eyes (dark spots), a nose (a vertical line), and a mouth (horizontal line or curve), separated the appropriate amount and perhaps tilted or angled.  So you'll get the occasional false positive like this.  I'm sure Google and Facebook have significantly improved their algorithms over the years.

You can throw away the existing face rectangles and label's you've assigned by selecting the photos and doing Library > Find Faces Again.  If you originally started running face detection before LR 7.3 (2018), this could have a significant effect, since the face engine was replaced in 7.3, and though LR was supposed to automatically rerun detection with the new engine, it may not have done that correctly.   And if you want to significantly change the names you've assigned faces, it could be easiest to select all your photos and run Find Faces Again. 

But keep in mind that face detection is a deterministic algorithm -- given the same inputs, it always produces the same outputs.  So in general it only makes sense to do Find Faces Again if you plan on making a much different assignment of names to face rectangles.


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## Linwood Ferguson (Sep 6, 2021)

I've spent a lot of time with it, and while I agree with you, I think the value in the facial recognition system in lightroom is more in the mechanism than its accuracy.  The accuracy is pretty terrible, but it does provide a relatively easy mechanism for the human to correct its tentative labels -- easier than doing it by hand with no help.

What bothers me more than inaccuracy, or false positives such as your beetle, is false negatives.  All to often it just passes over a face entirely, so that if you spend your time just relabeling its guesses, you also miss it.  I find I have to go through every single photo and draw in my own faces in many cases.  And some of them are just absurd, I've seen cases where almost the entire frame is a face and it just skips it, especially if it's a profile as opposed to frontal view. 

I sure wish Adobe would put some effort into this aspect.  It has great potential, but it's old and inaccurate.  But... better than nothing.


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## johnrellis (Sep 6, 2021)

Ferguson said:


> I sure wish Adobe would put some effort into this aspect.  It has great potential, but it's old and inaccurate.  But... better than nothing.


Agreed. I use it in my personal catalog.


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