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Author Topic: Rough surface problem...  (Read 5287 times)

Lambo

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Rough surface problem...
« on: January 20, 2014, 08:18:27 AM »
Hello everyone again!  I have been tinkering with the program some more and taking some photos but for some reason  even though they are getting better, they still have some strange "bubble" like rough surface all around.
I am posting a picture of the problem and I will attach 1 of the pictures I used for the scanning so maybe you guys  can spot an issue there?
I am using 6 Nikon D5100 with the stock 18-55 lens. Settings are: ISO 200 ( I know 100 is better but I need more light :) 1/30, F8 30 on the focal length. I am using the maximum quality for the JPG and 16 Mpix.
Thanks in advance for your help...
Leo



Alexey Pasumansky

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Re: Rough surface problem...
« Reply #1 on: January 20, 2014, 01:30:39 PM »
Hello Leo,

If you are interested in face scanning results then it will be reasonable to place cameras closer to the person, so that image frame is used effectively. Also it will be interesting to see the camera positions in the model view mode.
Best regards,
Alexey Pasumansky,
AgiSoft LLC

Wishgranter

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Re: Rough surface problem...
« Reply #2 on: January 20, 2014, 01:45:00 PM »
Hi Leo, see the red "circles" that i paint. there is clearly to see that the person has done slight movement between shots, the DEPHT maps-mesh could not be correctly placed-reconstructed. 18 cams for body is absolute minimum with no guarantee of sucess.... or to low points were aligned( because of just 6 cams ) .....
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Andrew

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Re: Rough surface problem...
« Reply #3 on: January 20, 2014, 01:59:33 PM »
Make sure you If you are sure your cameras are well focused and retrieve nice sharp detail of subjects face (sharp spots, blemishes even skin pores). Capture must be fast enough to avoid any subject movement.
If  you are still getting noisy mesh, most likely your cameras are positioned too far apart from each other. Higher ISO definitely increases noise in mesh but ISO 200 should not be that bad.

Lambo

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Re: Rough surface problem...
« Reply #4 on: January 20, 2014, 09:18:40 PM »
Thanks all for the answers, there is some good insight in them.
But to clarify something since I didn't explain correctly, I used 6 cameras, but they are in a fixture I created so they are 6 in the vertical axis but I took 9 shots from left of the subject to right of the subject (front half body shot) so a total of 54 shots.
Leo

David Cockey

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Re: Rough surface problem...
« Reply #5 on: January 21, 2014, 06:24:08 AM »
My understanding is most/all Nikon DSLR's have ISO 200 as the base ISO and there is no reduction in noise with ISO 100.

Which "quality" settings are you using for alignment and dense cloud generation?

Lambo

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Re: Rough surface problem...
« Reply #6 on: January 21, 2014, 06:55:08 AM »
Hi David, my settings are these:  Accuracy: High, Pair Selection: Disabled, Point Limit: 400000
Dense Cloud Generation:  Quality: High, Depth Filtering: Mild.
I am attaching a couple more shots of the way the Alignment ended up that for what I know it seems very good. There are a couple cameras that are missing since when I did the shoot, they didn't fire ( I am using for now a couple of the IR wireless remotes to make them fire at the same time until I can get something better :)
Thanks all for your help!
Leo



Lambo

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Re: Rough surface problem...
« Reply #7 on: January 21, 2014, 07:34:07 PM »
Ok I found another thing that might be the reason for this. Some of the pictures are not in focus. I am guessing the fact that I am taking the pictures with the IR remote, even though it is set to auto focus, they are not doing a good job at it. The ones in focus are great but there are quite a few out of focus.
I know that is pretty bad for trying to accomplish a good capture but could that cause this kind of rough surface? I would have thought out of focus pictures would cause simply bad alignment and some cameras not being able to align at all but not a surface like this?
Leo

James

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Re: Rough surface problem...
« Reply #8 on: January 21, 2014, 08:04:46 PM »
Like wishgranter said it looks exactly like what you would expect to see if the subject had moved between captures.

Assuming the 6 fixed cameras fired approximately simultaneously each time then you should not see these artifacts if you try working with just a single set of 6 images, only when you try combining more than one set.

Perhaps even 2 or 3 sequential sets of 6 images would be close enough together in time that any movement was small enough to not cause this, but it seems that over the 9 sets there was 'significant' movement.

Regarding focus, perhaps try to keep a constant distance and set focus manually. This would enable you to fire off your 9 sets of images more quickly too, plus photoscan prefers when sets of images have identical camera parameters (see in tools -> camera calibration) - changing focus changes the internal parameters such as focal length and distortion slightly each time.