Lightroom: Face detection fails when face is not upright

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  • Updated 3 years ago
  • (Edited)
After tagging many photos of a person, Lightroom will still fail to recognize the same person simply because the person has tilted their head, is lying on a couch, etc. I've seen this happen even with two photos where the person has the same expression on their face, is under the same lighting, has the same background, etc.

While searching for faces, Lightroom should also consider rotations, at least up to 90° either direction.

I do occasionally see this on photos where the face is rotated more than 90°, but these are rare enough that I wouldn't mind if Lightroom didn't bother trying to look for these, simply in the name of reasonable processing time. That said, if there is such a restriction, it should be lifted as quickly as Moore's Law permits.

The rotation amount should factor into the algorithm's plausibility rating for the photo. If there are two likely choices after the algorithm does its thing, but one requires considering the photo at a high angle of rotation, the one with less rotation should be considered more likely. This should not be enough by itself to throw the result, but it should be a factor. For instance, if it gets an 80% confidence for Person A at 35° but only 20% at 5° for Person B, it's more likely to be a photo of Person A with their head tilted than a bad photo of Person B.
Photo of Warren Young

Warren Young

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Posted 3 years ago

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Photo of Simon Chen

Simon Chen, Principal Computer Scientist

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This is expected. Lightroom can detect upright faces +/-15°. 

Detecting faces in other image orientations would slow down the indexing a lot and could detect "faces" where there are not. 

A workaround: manually rotate the photo to make sure the faces that you wanted are upright. Lr would keep track and rerun the face detection on the photo for the current image orientation (assuming you haven't made any modification to the faces detected earlier because Lr does not want to override your changes). You can then tag the faces and rotate the image back to the orientation if you want.