Scanning outdoors in daylight or direct sunlight


#1

Hi everyone,

Did anyone actually try to scan anything outdoors?
I know that sun lit areas will have issue but I find that even just bright outdoor lighting is a problem.
Depth data is almost unusable if it’s even there and the tracking is not working.

Is that because of IR light interference from the sunlight?
Would the current hardware will be able to handle any of this in the future?

Thanks


#2

Thanks for the great example screenshot. There are actually two challenging bits here: 1) the sunlight does interfere and overpower the Structure Sensor’s IR emitter, and 2) this black furniture is likely absorbing IR light as well. You can see that the wood planks are sensed, but the furniture is not – even in the shadowed area where the sun is not interfering as much.

Future software upgrades may be able to achieve some functionality in this kind of setting, but it will always be very challenging for the sensor itself. Any eye-safe 3D sensing system on the market today will have this same difficulty.

Imaging this kind of setting at dusk is the best solution at the moment. And even at dusk, make sure to get close enough to the black furniture since its absorptivity is high.


#3

I’ve had moderate success in bright daylight. I found that it’s best to frame the subject backlit by the sun to get a somewhat usable scan (this is using itSeez3D).

I did a bunch of scans on a rooftop 2 weeks ago with mixed results. If you check out this scan it took multiple attempts at positioning to get this result by facing the subject away from the sun. Her back has some texture issues on her head probably due to IR interference caused by the position of the sun.


#4

Thanks Jeff.
I was actually able to capture that outdoor furniture at night in complete darkness so I think it’s more the IR interference then anything else. I guess a more powerful IR emitter would not be eye safe, as you mentioned.

I have a question about the point cloud density but I’ll start a different topic for that.


#5

Hi,
I actually tested my sensor for the first time outside. And I was a little bit surprised that even though I didn’t try it in bright sunlight, it didn’t really scan anything!
I was a little bit disappointed, and I was thinking whether any reflections of anything messed with the sensor range.
One of the main reason I decided to buy the sensor was to be able to scan and pay landscapes, to be in the background of my 3-D models as an architect. I am sure that with more experience and using the Scantek program on the laptop, this is definitely easier to do. However I will somehow thinking that the product would work right out of the box, iPad only.

Has anyone succeeded in producing anything of better quality outside?

Michael


#6

I find it a little funny that 3D Systems is marketing their branded version of the Structure on their site with photos of it in use in bright sun where it actually can’t be used:

http://cubify.com/en/Products/iSense

Even indoors near a big window is near impossible to get the scanner to lock onto anything due to the brightness of the sunlight overpowering the sensor.


#7

I actually have had pretty good tracking results both in and outdoors. I am using the scanner app on an Ipad air. Even indoors in our fully windowed lobby.


#8

John, you’re right. I saw their video before but now that I had a chance to try it hands on, I wouldn’t quite use the word “funny”. I think their promotional video is very misleading, at the very least. I don’t quite buy the scan of that outdoor statue in such a breeze, especially the cropping and 3D printing. I mean it’s possible but you’ll have to jump through a lot more hoops.

HollowDeck, can you attached screenshots or an example of something that you’ve successfully scanned outdoors or in daylight?


#9

I am a new Structure Sensor user. So new that as I type this, UPS just rang my doorbell to deliver it (not kidding, they just did:smiley:). Over the last few days while waiting, I have been looking around in the forum for posts related to how well the scanner performs outdoors as this is one of my intended uses. It sounds like one of the major issues is that the IR from sunlight can interfere and even overwhelm the IR from the scanner, thus making it difficult to get a usable scan. In other words, a signal-to-noise ratio problem (the signal being the IR from the scanner and the noise being that from the sunlight).

To prevent this, one needs get rid of most of the IR portion of the sunlight illuminating the scene. Our eyes don’t need the IR to see, and the camera doesn’t need the IR to form an image. One way to do this, as some have suggested, is waiting for times when it is overcast, during twilight, or nighttime. This significantly reduces the IR portion of the light illuminating the scene compared to the IR originating from the scanner, improving the signal-to-noise ratio.

I thought about another approach that might be worth considering, that is using transparent IR-blocking plastic film to block the sunlight coming through a window, or illuminating a portion of the scene outdoors. There are many sources of this film. Here is one, for example, that has 5’ to 6’ wide rolls of IR-blocking film (e.g. about $110 for 10’ roll depending on type).

Apex infrared blocking film

I realize that it would be impractical to try to do this for a large area illuminated by sunlight. But with a portable frame of this stuff placed between the sun and the scene it might be possible to capture such a scene in sections. I have not tried this yet, obviously, since I just got my Structure Sensor but I though it might be helpful to someone in a situation where direct sunlight is unavoidable.

Thanks, and now I am going to open my package!