16 ms·

The strobing seems to defeat the effect -- you only need one good frame with a face showing to defeat the hoodie, and this seemed slow enough that I could pick

The strobing seems to defeat the effect -- you only need one good frame with a face showing to defeat the hoodie, and this seemed slow enough that I could pick up the face of the demo guy with my own eyes in realtime.

jwong_ 4y ago
Seems like the strobing is intended to defeat the autoexposure compensation. Otherwise the camera might see the brightlight and reduce exposure to compensate. Concentrating the lighting on the face only and staying far away from cameras might help that without requiring the strobe.
- wstuartcl 4y ago
  The leds are placed on the chest -- seems like a miss to not place them also around the hoodie near the face. I would suspect even without strobing the over saturation would work should those leds be surrounding the face. All of that said, wearing something like this out (unless it becomes super commonplace lol) just screams watch me closely (and easily follow me back to some known origin).
  - tablespoon 4y ago
    > The leds are placed on the chest -- seems like a miss to not place them also around the hoodie near the face. Based on the documentation, all that would probably do is allow the effect to work at slightly closer distances.
  - tablespoon 4y ago
    > The leds are placed on the chest -- seems like a miss to not place them also around the hoodie near the face. Based on the documentation, all that would probably do is allow the effect to work at slightly closer distances: > In addition, the LEDs need to be a minimum distance from the camera to be effective, as the cone of light from them needs to be wide enough to overlap with the cameras view of the wearers head. In practice, this is about 12ft (~3m). Putting them on the chest would help with ergonomics. It would work even if you have the hood off and the LEDs would be more consistently positioned.
- bsenftner 4y ago
  FR developer here: that strobing is very smart, as the mechanical mechanism starts to adjust the strobe generates another adjustment. If the strobing is at a random interval, it becomes difficult to impossible to compensate in software. FR does not work without face images.
  - dylan604 4y ago
    I would think randomizing the strobing would be effective as well. All of this defeating of auto exposure adjustments makes me think back to the days of Macrovision and how easily it could be defeated as it was not randomized at all. Then again, it was also easily just stripped out of the signal.
    - sacrosancty 4y ago
      With random timing, you're more likely to get one period that's long enough for the auto-exposure to correct it and see the face. Autoexposure takes time because it has to use a feedback loop to search for the correct exposure, so if the brightness changes fast enough, it can't keep up.
      - dylan604 4y ago
        you set a maximum on period so that doesn't happen. if you develop something with a known pattern, that can be programed in to be countered. hence my example of Macrovision. randomizing the values means it is much harder to counter.
  - amelius 4y ago
    All the camera would have to do is ignore the brightest parts of the image, then correct the ExposureTime based on that image.
- nkozyra 4y ago
  That's what they say, but how much autofocusing is actually happening? In the example video the scene is mostly in focus. My guess is it actually messes with the exposure rather than focus.
anonu 4y ago
Agreed that was not a good demo. I assumed that segment was not taken with a cheap webcam/security camera - which is why the auto-exposure worked a lot faster. At a greater distance with lower MP security cameras, this thing might still work.

jwong_ 4y ago

Seems like the strobing is intended to defeat the autoexposure compensation. Otherwise the camera might see the brightlight and reduce exposure to compensate. Concentrating the lighting on the face only and staying far away from cameras might help that without requiring the strobe.

wstuartcl 4y ago
The leds are placed on the chest -- seems like a miss to not place them also around the hoodie near the face. I would suspect even without strobing the over saturation would work should those leds be surrounding the face. All of that said, wearing something like this out (unless it becomes super commonplace lol) just screams watch me closely (and easily follow me back to some known origin).
- tablespoon 4y ago
  > The leds are placed on the chest -- seems like a miss to not place them also around the hoodie near the face. Based on the documentation, all that would probably do is allow the effect to work at slightly closer distances.
- tablespoon 4y ago
  > The leds are placed on the chest -- seems like a miss to not place them also around the hoodie near the face. Based on the documentation, all that would probably do is allow the effect to work at slightly closer distances: > In addition, the LEDs need to be a minimum distance from the camera to be effective, as the cone of light from them needs to be wide enough to overlap with the cameras view of the wearers head. In practice, this is about 12ft (~3m). Putting them on the chest would help with ergonomics. It would work even if you have the hood off and the LEDs would be more consistently positioned.
bsenftner 4y ago
FR developer here: that strobing is very smart, as the mechanical mechanism starts to adjust the strobe generates another adjustment. If the strobing is at a random interval, it becomes difficult to impossible to compensate in software. FR does not work without face images.
- dylan604 4y ago
  I would think randomizing the strobing would be effective as well. All of this defeating of auto exposure adjustments makes me think back to the days of Macrovision and how easily it could be defeated as it was not randomized at all. Then again, it was also easily just stripped out of the signal.
  - sacrosancty 4y ago
    With random timing, you're more likely to get one period that's long enough for the auto-exposure to correct it and see the face. Autoexposure takes time because it has to use a feedback loop to search for the correct exposure, so if the brightness changes fast enough, it can't keep up.
    - dylan604 4y ago
      you set a maximum on period so that doesn't happen. if you develop something with a known pattern, that can be programed in to be countered. hence my example of Macrovision. randomizing the values means it is much harder to counter.
- amelius 4y ago
  All the camera would have to do is ignore the brightest parts of the image, then correct the ExposureTime based on that image.
nkozyra 4y ago
That's what they say, but how much autofocusing is actually happening? In the example video the scene is mostly in focus. My guess is it actually messes with the exposure rather than focus.

anonu 4y ago

Agreed that was not a good demo. I assumed that segment was not taken with a cheap webcam/security camera - which is why the auto-exposure worked a lot faster. At a greater distance with lower MP security cameras, this thing might still work.