Tips for scanning

Write here about construction, ideas, equipment, tips n tricks etc. related to structured light scanning
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tore
Posts: 3
Joined: 17 Apr 2017, 19:43

Tips for scanning

Post by tore »

Tips for improving scans,

Hi all, I recently got into this amazing world of 3d scanning. I’ve been playing around with the software and trying to do some scans, although I’ve managed to get a few scans that look close to the object I am scanning, I am still getting a lot of issues and need improvement of my scan quality.

My main issues so far are that with every scan I do, I get this rough wave like texture on the surface; And I have a hard time fusing the scans, especially if it is a cylindrical shape.

My setup is a follows:

Camera: Canon t3i
Scanner: Acer k130

Should I get a different camera? Do you have any tips or comments on how to improve my setup/scanning?

Many Thanks!!!
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Oteck
Posts: 82
Joined: 11 Nov 2016, 21:21

Re: Tips for scanning

Post by Oteck »

Settings? picture of what your scanning would help too. Im guessing your using 32bit david4 to do this

exposure, calibration scale, ect
tore
Posts: 3
Joined: 17 Apr 2017, 19:43

Re: Tips for scanning

Post by tore »

Hi Oteck

yeah I am using David4 32bit, I include a couple of pictures of the setup and vase.
Exposure is 1/60,(I cant modify it from the software) calibration scale is the default A3 panels (211.5 mm)
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Oteck
Posts: 82
Joined: 11 Nov 2016, 21:21

Re: Tips for scanning

Post by Oteck »

Not sure about others but i try to scan in the darkest place possible with little ambient light contaminating like a corner of the room and enclose it in blankets. also whats your frame limit set to?

Also you'll need to make sure that the camera and mainly the projector doesn't move or your scans will never line up. That k132 has a very terrible tripod mount so id find a better way to secure it
Curiousjeff
Posts: 121
Joined: 16 Nov 2016, 22:31

Re: Tips for scanning

Post by Curiousjeff »

I have written many post about using a Canon with David in the old David forum using the Canon live view.
Narmella has many more post for using frame grabber.

http://forum.david-3d.com/index.php

If you are using live vew, the resolution is not very high, but it's a good place to start with David.

You can modifiy the camera settings directly on the camera to find the best settings. No need to have it done through David.

If available on your camera, you could install MagicLantern.

The most important is to have a stable image in the live view within David. Of course no shaking, but also no lines going across the screen (out of sync problems). No pulsing image either. To more stable the better. Look also if the red sine waves are moving.

To obtain a stable image, you can try to adjust shutter speed (1/60, 1/30,1/15), fine tune with Magiclanter , and/or change projector frequency if your video cards permits.

Once all this is resolved, you can fine tune your scan by making further adjustments within the advance settings of David.

Jeff

P.S. I had a better look at your images. It's a good start. Bring quality check and outlier removal to zero at first. Also, make sure your sine waves are as decribed in the David manual.
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Micr0
Posts: 586
Joined: 15 Nov 2016, 15:20
Location: New York City

Re: Tips for scanning

Post by Micr0 »

Oteck wrote: 18 Apr 2017, 01:13 Not sure about others but i try to scan in the darkest place possible with little ambient light contaminating like a corner of the room and enclose it in blankets. also whats your frame limit set to?

Also you'll need to make sure that the camera and mainly the projector doesn't move or your scans will never line up. That k132 has a very terrible tripod mount so id find a better way to secure it
I think he has too many post-it notes in the room. That is never a good thing. :D

Less ambient light would be a good start, as getting your exposure/levels right I suspect is more your problem.
µ
Oteck
Posts: 82
Joined: 11 Nov 2016, 21:21

Re: Tips for scanning

Post by Oteck »

What resolution are you getting from live view? looking closely it seems very low. Also note that video coming from that form is compressed so it's not the best quality. You can probably try the hdmi feed but you need the magiclantern hack to get the clean progressive output.
tore
Posts: 3
Joined: 17 Apr 2017, 19:43

Re: Tips for scanning

Post by tore »

Hi all,

Thank you so much for your answers and info; its been really helpful, below some comments and questions, sorry for the long post!

@Oteck
Not sure about others but i try to scan in the darkest place possible with little ambient light contaminating like a corner of the room and enclose it in blankets.
Also you'll need to make sure that the camera and mainly the projector doesn't move or your scans will never line up. That k132 has a very terrible tripod mount so id find a better way to secure it
Yeah, Im living in the tropics for now so there is light everywhere! Definitely need an enclosure; I will use some black board panels for that. I’m currently using a very cheap tripod, I’m on the hunt for better one or might just build a custom platform.
also whats your frame limit set to?
Not sure what this is, is it 0? (image 1)

@Curiousjeff
I have written many post about using a Canon with David in the old David forum using the Canon live view.
Narmella has many more post for using frame grabber.
Thanks, there is a lot of very useful information I am going through it in the old forums
Is frame grabber the same as image grabber? If it is different, where do I access frame grabber?
you are using live vew, the resolution is not very high, but it's a good place to start with David.
You can modifiy the camera settings directly on the camera to find the best settings. No need to have it done through David.

If available on your camera, you could install MagicLantern.
I have just installed MagicLantern really nice software, although not sure how to use it with David, besides the aperture is there anything else I can modify with it?
The most important is to have a stable image in the live view within David. Of course no shaking, but also no lines going across the screen (out of sync problems). No pulsing image either. To more stable the better. Look also if the red sine waves are moving.
will keep an eye on that

If I understood correctly there are two options when using a canon: live view and frame grabber, with live view being low resolution and frame grabber a better one but takes a bit more steps and Narmella later develop a code called Letscan based on Frame grabber. Is this correct?
P.S. I had a better look at your images. It's a good start. Bring quality check and outlier removal to zero at first. Also, make sure your sine waves are as decribed in the David manual
Ok ill double check that

@ micr0, lol yeah those keep me distracted :D

@OTeck
What resolution are you getting from live view? looking closely it seems very low. Also note that video coming from that form is compressed so it's not the best quality. You can probably try the hdmi feed but you need the magiclantern hack to get the clean progressive output.
Live view the same as selecting my camera from the options right? If so I think I get 1056 x 704.(image 2) So far I am using default setting when plugin the camera to the PC. Can I change this with Magic Latern?
What is the hdmi feed?
How do I set up that hdmi feed with magiclantern?

I was going to ask what would be a good camera to buy after getting some experience with the canon, but after seeing the impressive results obtained by narmella using Letscan, should I still invest in another camera or stick with using the canon? If another camera will help me achieve faster/higher quality results what would be a good option?

Thanks again guys!
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a1.jpg
Curiousjeff
Posts: 121
Joined: 16 Nov 2016, 22:31

Re: Tips for scanning

Post by Curiousjeff »

My mistake. I should have written "image grabber" and not "frame grabber".

You have three possibilities with a most Canon DSLR:

Live view
Image Grabber
HDMI capture using a HDMI capture device and Magic Lantern

Live view has a low resolution
Image grabber, personally was too slow and complicated. But give it a try. Narmella software does make the task faster.
HDMI needs Magic Latern to get a clean hdmi output. The other main problem is the interlaced signal (1080i).

As per my experience, it's better to use a Nikon for that.

Using live view or the HDMI output, Magiclatern will allow you to make very fine adjustement to the shutter speed, to get the best possbile sync between camera and projector. On the other hand, if you get a good sync "out of the box" at 1/60 or 1/30,no need to play with Magiclantern.

The live view resolution cannot be modified.

Jeff
Oteck
Posts: 82
Joined: 11 Nov 2016, 21:21

Re: Tips for scanning

Post by Oteck »

I didn't get much success out of my 7d in live view so i gave up on that idea... and it doesn't work on 5 which is fine as buying 2x the camera body and lenses is out of the question.

It's a fine tool just to play with to get an idea how the system work but it's not ideal as mentioned. My c1 does the task much better even if it's slow...
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