[HN Gopher] Wrist-mounted camera captures entire body in 3D
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       Wrist-mounted camera captures entire body in 3D
        
       Author : PaulHoule
       Score  : 30 points
       Date   : 2022-11-10 18:34 UTC (4 hours ago)
        
 (HTM) web link (news.cornell.edu)
 (TXT) w3m dump (news.cornell.edu)
        
       | agarsev wrote:
       | The press release contains a few errors and imprecisions. The
       | abstract from the scientific article is more informative:
       | 
       | In this paper, we present BodyTrak, an intelligent sensing
       | technology that can estimate full body poses on a wristband. It
       | only requires one miniature RGB camera to capture the body
       | silhouettes, which are learned by a customized deep learning
       | model to estimate the 3D positions of 14 joints on arms, legs,
       | torso, and head. We conducted a user study with 9 participants in
       | which each participant performed 12 daily activities such as
       | walking, sitting, or exercising, in varying scenarios (wearing
       | different clothes, outdoors/indoors) with a different number of
       | camera settings on the wrist. The results show that our system
       | can infer the full body pose (3D positions of 14 joints) with an
       | average error of 6.9 cm using only one miniature RGB camera
       | (11.5mm x 9.5mm) on the wrist pointing towards the body [...].
        
       | chatterhead wrote:
       | "BodyTrak is the latest body-sensing system from the SciFiLab..."
       | 
       | Name checks out. This kind of tech isn't going to be used
       | primarily in smartwatches it's going to be integrated into state-
       | based surveillance.
        
         | Avshalom wrote:
         | "State-based" my ass
         | https://www.theguardian.com/technology/2018/jan/31/amazon-wa...
        
         | NavinF wrote:
         | You can always count on HNers to point out that a neutral
         | network designed to run realtime on devices that have a 1 watt-
         | hour battery definitely "isn't going to be used primarily in
         | smartwatches". The US gov't can't possibly afford to do offline
         | pose estimation on a real GPU, am I right?
        
       | system2 wrote:
       | I love these extremely boring articles with zero pictures or
       | videos.
        
         | genpfault wrote:
         | https://matthewdressa.github.io/Personal-Portfolio/assets/pd...
        
           | idiotsecant wrote:
           | Thanks for the link!
           | 
           | The camera shots that are shown in that paper are _really_
           | restricted in what they can see. How can the model possibly
           | estimate the position of an arm that is not visible?
        
             | Corazoor wrote:
             | Probably by learning how humans have to balance their
             | extremities to remain standing upright. The camera angle
             | with respect to the enviroment is likely a factor too,
             | since errors got larger when outdoors.
             | 
             | Errors are also not exactly small, ~6cm average, although
             | it's more like 1-2 or 5-12, depending on body part. I think
             | this would very likely be noticeable in VR applications,
             | but it is still very impressive accuracy overall.
             | 
             | The question also nicely highlights the disadvantages of
             | trained algorithms: No one knows for sure, and it certainly
             | isn't obvious by looking at the network weights...
             | 
             | On the other hand, when looking at the pictures, I felt
             | like the authors: There should be enough information in
             | there to get at least a good estimate. And it is extremely
             | useful that one can nowadays "just" train a model to
             | confirm such theories.
        
         | PaulHoule wrote:
         | Beats the animated GIF memes that cause seizures
        
       | VikingCoder wrote:
       | ...is there a video?
        
       | RasmusWL wrote:
       | https://www.scifilab.org/bodytrak has _something_ at least, but
       | still very little :(
        
       | Animats wrote:
       | "ANONYMOUS AUTHOR(S)"?
       | 
       | This is an interesting approach, but full body tracking with a
       | few sensors is already much better than this at the $150 price
       | point.[1] Because it will suffer badly from occlusion, it will
       | probably do well in expected situations and terribly in
       | unexpected and occluded situations.
       | 
       | [1] https://www.youtube.com/watch?v=ImEKHrUp4QM
        
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       (page generated 2022-11-10 23:01 UTC)