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View Full Version : Capturing 3D Surfaces Simply With a Flash Camera



geothefaust
08-31-2008, 12:37 PM
Article here (http://www.hothardware.com/News/Capturing-3D-Surfaces-Simply-With-a-Flash-Camera/).

Thought this was worthy of posting. Definitely sounds interesting.

Bytehawk
08-31-2008, 06:52 PM
indeed,

one to watch out for

T-Light
08-31-2008, 07:29 PM
Oh that's neat.

Wonder how long it would take to write some code to do that? Already thought of way too many problems that would make it a quick exercise.

edit - glossy surfaces being the biggy.

Svenart
08-31-2008, 07:39 PM
boah thats HOT :)

geothefaust
08-31-2008, 07:40 PM
Hey,

Yeah glossy surfaces would be a real bummer. :(

T-Light
08-31-2008, 08:27 PM
Hello there :)

Went to a castle the other week grabbing old stone textures. They had a dungeon and a torture chamber. The torture chamber was very damp, the floors were actually soaken, the dungeon was dry but was so small that even with the flash on the lowest setting it still caused burnout. Guess it's manual work on this sort of stuff for the time being.

Excellent link though, thanks a bundle (He who couldn't sleep, had a nightmare, gave up after two hours and thought he'd work instead - I'm not doing very well am I? :D)

Here's that torture chamber on an 8 second exposure for anyone who likes a bit of ancient castle type stuff, would have loved to have used that technique in there.

borkus
09-01-2008, 08:53 AM
Thanks for the share T-light. I wish I lived close to something like that. Seems that castles never caught on big here in the states... Us americans have no sense of grandeur...

T-Light
09-01-2008, 01:29 PM
Your welcome borkus :)

It was a shame really, we were driving home and stopped in a place called Alnwick for fish and chips, didn't find any. We did find Alnwick Castle though, absolutely OUTSTANDING. Unfortunately it was closed. We'd decided against it the previous day thinking it would be a bit touristy. This panoramic doesn't do it any justice, it was raining heavily and we were loosing light fast.

It's just stunning, we're going to get back there asap :thumbsup:


ps (this is also the castle used in Harry potter)

pooby
09-02-2008, 02:28 AM
My Studio is in a castle.


It's not quite in the same league as Alnwick, but, y'know we like it.

T-Light
09-02-2008, 04:15 AM
Wow, that's some size, the last pic you showed just looked like a turret behind a tree. That's huge.

(pushes seething jealousy under the desk)

Iain
09-02-2008, 06:45 AM
My Studio is in a castle.


Nice studio!

I trust you all dress appropriately?

pooby
09-02-2008, 08:07 AM
I'm the boss, so I have a crown and robes.. The paupers artists all wear sackcloth, unless they do something cool like reduce rendertimes by 50% whilst retaining the same quality. In which case I knight them and they get to wear a helmet and codpiece for the rest of the day.

hrgiger
09-02-2008, 08:09 AM
My Studio is in a castle.


It's not quite in the same league as Alnwick, but, y'know we like it.

So they let you park your studio there? It's nice and shiny.:devil:

pooby
09-02-2008, 08:12 AM
Off with his head! cheeky bugger :)

Jim M
09-03-2008, 04:11 AM
There is a trick I read somewhere, where you can do something similar.
You set up some lights and take photos under different lighting and combine the different light setups into a normal map & colour texture. From the normal map you could get an approximate height field ... so it would work. You just need a dark box with a few lights and a fixed position camera.... fcuk it I am going to do it now.... wheres that saw

regularfry
09-03-2008, 06:16 AM
I've written some software to do something similar - you put a paper target on the thing you want to capture, and take 3 pictures with a fixed camera but moving light source, and out pops a normal map. Integrate across the normal map, there's your height field. Now I'm just trying to figure out how to make money out of it :-)

It's not as slick as this technique, but it works well enough.

Jim M
09-03-2008, 06:30 AM
Now I'm just trying to figure out how to make money out of it :-)

Make a 'studio box'.

pooby
09-03-2008, 08:02 AM
Surely someone's invented some software to make a depth map from 2 slightly offset photographs.
That must be basic to make.

regularfry
09-03-2008, 08:08 AM
Surely someone's invented some software to make a depth map from 2 slightly offset photographs.
That must be basic to make.

There are limits to what you can do with that. If I remember correctly, the depth precision sucks. Our brains actually only use static images for scene reconstruction in the near-field. The distances to far-field objects are estimated from parallax motion.

EDIT: I should mention that using separate images for near-field scene reconstruction was pretty unfeasible until recently; Photosynth solves that problem, though.

Jim M
09-03-2008, 10:51 AM
Surely someone's invented some software to make a depth map from 2 slightly offset photographs. That must be basic to make.

Yeah definitely handy for close up stuff. I am sure I have seen a freeware one kicking about....

geothefaust
09-03-2008, 11:04 AM
Brent, awesome torture chamber. I too wish I lived close enough to something like that where I could just stroll in for a peek. :D Cool stuff.

Pooby, I was telling someone the other day I know, about your castle/studio, and how jealous I was, lol.

Jim M & regularfry, awesome! That's pretty awesome to hear that there is something like that kicking around already. I really like that idea about using colored lights to generate a normal map, especially.

Jim M
09-03-2008, 11:28 AM
You don't need coloured lights. Just a fixed camera position and white lights.
Then you Capture a colour plate, and however may you need for a normal map with the white lights in the right places to simulate U or V etc, then in Photoshop you just effectively 'channelize them' ... try it...

rakker16mm
09-04-2008, 02:41 PM
You don't need coloured lights. Just a fixed camera position and white lights.
Then you Capture a colour plate, and however may you need for a normal map with the white lights in the right places to simulate U or V etc, then in Photoshop you just effectively 'channelize them' ... try it...

I was thinking this might be done in photoshop but I was thinking of setting the blending mode to difference in the layers pallet on a de-saturated copy of the picture.

Stooch
09-06-2008, 01:17 PM
LOL. thats their tech???

holy crap i have been doing this for years. its as simple as taking a pic with alot of ambient light (cloudy days or afternoon) and take another with front lighting. light kits are quite handy for this, if you aim the lights away from your pic they will bounce around the room and give you your relief.

take the ambient pic into photoshop desaturate, play with levels and blend with the front lit pic. what sucks about this method is that you need a tripod. btw you can generally pull out height info with a little bit of photo manipulation in photoshop anyway if you play with curves and use a little bit of creative layer blending. the key is taking good pics to begin with and avoid lighting conditions that cause relief shadows, which this tech doesnt seem to address.

JeffrySG
09-06-2008, 02:42 PM
This is the tutorial that shows how to create a normal map from four photos... pretty simple and cool...

http://www.zarria.net/nrmphoto/nrmphoto.html