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How can Tesla do rain sensing on AP2?

Discussion in 'Model S' started by thegruf, Jul 21, 2017.

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  1. thegruf

    thegruf Active Member

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    Been bugging me this one, and now relevant to me having switched to an AP2 ModelS

    Tesla don't seem to have any quick answers either, though the images of the Model3 don't seem to show a rain sensor either, so they must have a concept of how to do it at least.

    The biggest issue with the cameras is that they are deliberately designed to be out of focus at the range of the windshield glass, else every bit of dirt (and rain!) would ruin AP performance.

    So if the image is out of focus close up - how are Tesla going to "see" the rain without a separate sensor?

    Use the cameras
    to "see" the raindrops at distance - is this possible to check for appropriate noise between successive images?
    to look for wet pavement - inaccurate
    to watch other cars wipers? - only works if there is other traffic
    (and when all cars are Teslas would be interesting, first one to manually use the wipers sets the whole fleet going!)
    check tor spray using the rear camera - not impossible but likely inaccurate

    Use internet based rainfall radar? - intersting but not accurate enough

    radar - nope?

    somebody explain how this can be done please
     
  2. Matias

    Matias Active Member

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    Raindrops on lens cause characteristic flare on picture. I think they train neural net to detect this.

    IMG_1066.JPG
     
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  3. WarpedOne

    WarpedOne Supreme Premier

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    I see a rain sensor ...

    [​IMG]
     
  4. J1mbo

    J1mbo Member

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    That's a light sensor, not a rain sensor...
     
  5. lunitiks

    lunitiks ˭ ˭ ʽʽʽʽʽʽʽʽʽ ʭ ʼʼʼʼʼʼʼʼʼ ˭ ˭

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    According to the parts manual, it's a "Light/Temperature/Humidity"-sensor. One could argue that rain is pretty humid... But it's still a strange word to use for something that's supposed to detect rain (why call it "humidity"). The same sensor is also called "HVAC-sensor" in Teslas service manual. Anyway, the sensor in question is attatched to a custom Tesla PCB (so no off-the-shelf stuff like AP1-cars have, which is manufactured by HELLA).

    So either they ran into problems with that LTH-sensor, or its taking longer than expected to train the neural nets to flawlessly detect rain drops with the cameras...
     
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  6. J1mbo

    J1mbo Member

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    IIRC the temperature & humidity measurement is for the sensor side of the glass, to control the demisting wires in front of the cameras.
     
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  7. nowtleft

    nowtleft Member

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    They simply dont work until there is so much rain on the windscreen you have to either flick wipe or switch wipers on full. Why mess with rockets if you cant sort a rain sensor out or buy one from Ford that works?
     
  8. J1mbo

    J1mbo Member

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    Maybe because the auto sensors from "Ford" don't work so well in Full Self Driving cars when the driver has the "auto" bit switched off?
     
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  9. Haxster

    Haxster Member

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    Unfortunately, other things could produce the same flair patterns.

    Here's a scenario:
    You park under a tree on a hot day. Clear tree sap drops on the window over the camera. It drys hard. When you get in the car, it thinks there's a rain drop or two on the windshield. The wipers start and, because the sap is hard, they continue running.

    Maybe they should turn on the washer, but they don't. If they did, the car could run out of fluid before the tree sap was cleared. Life can get complicated.

    Note, this could also be an issue for conventional IR rain sensors.
     
  10. nowtleft

    nowtleft Member

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    I cant see why they wouldn't - thye are triggered by rain on the windscreen not how the cars autopilot is set up. Just remember my Mondeo's auto rain sensing wipers being very good:) (car was crap!)
     
  11. lunitiks

    lunitiks ˭ ˭ ʽʽʽʽʽʽʽʽʽ ʭ ʼʼʼʼʼʼʼʼʼ ˭ ˭

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    ... and for the cameras?

    Unavoidable issue.com?
     
  12. Tam

    Tam Active Member

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    I hope that is not the one that measures outside temperature as displayed on the dashboard because the windshield can get very hot!
     
  13. _jal_

    _jal_ Member

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    • Informative x 2
  14. whitex

    whitex Active Member

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    Ok, so what you're saying is Tesla with it's 8 cameras cannot tell whether it's dark outside, but they will be able to detect rain? You'd think it should be easier to tell day vs. night over rain vs. no rain.
     
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  15. lunitiks

    lunitiks ˭ ˭ ʽʽʽʽʽʽʽʽʽ ʭ ʼʼʼʼʼʼʼʼʼ ˭ ˭

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    Good point @whitex. Kind of a paradox
     

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