Dear DAVID Community,

As you are probably aware, the entire DAVID company, team and product range has been integrated into HP Inc.
This forum is now read-only. Relevant content has been migrated to HP and merged into HP's Support Forums on November 1, 2016.

To start new discussions for 3D Scanning, please register and post your new topic at the HP Support Forums

My First Scan - Sad

The place for questions, problems, comments and tips regarding the camera calibration.

My First Scan - Sad

Postby schneb » Thu Jun 19, 2014 2:23 am

I have a 24" x 18" ornamental bust that I have been wanting to scan. I downloaded the software into a fairly hefty PC. Got a green line laser, and printed out and built the alignment board. All went well in calibrating the HD Logitech camera, and the board. I made several, slow passes on the bust, but my results seem extremely poor. It got the initial outline of the object, but the detail looks horribly rough. When I made adjustments I then seemed to lose all my detail. Am I doing something wrong?
schneb
 
Posts: 5
Joined: Tue Jun 17, 2014 5:32 pm

Re: My First Scan - Sad

Postby WalterMo » Thu Jun 19, 2014 8:39 am

Obviously you did something wrong. But what? That's the question.

So we need more infos:
Post a photo of your set-up. Or some.
How do you move the laser line? Manually or by a motor?
Is the laser focusable?
How big is your calibration corner? Perfectly flat and at 90°?
What camera resolution have you used? The object is 59 cm x 44 cm. Maybe if it is very high detailed you need to scan it in several parts and align these perfectly.
What were the intersection angles (angle between camera and laser)?
viewtopic.php?f=2&t=3117&p=17498&hilit

Here in our Wiki is a how-to-do to scan a detailed bust:
http://wiki.david-3d.com/scanning_without_panels_by_hal
It was made by planeless scanning. That means the calibration corner is only 1x necessary for calibration and then not more. But this kind of scanning requires a special controller with stepping motor to pan the laser line.
User avatar
WalterMo
Moderator
 
Posts: 2363
Joined: Mon Apr 02, 2007 6:52 pm
Location: Braunschweig, Germany

Re: My First Scan - Sad

Postby schneb » Thu Jun 19, 2014 6:53 pm

Thanks WalterMo, I will attempt a photo of my setup soon.

    I was moving the laser by hand, and no it is NOT focusable. This may be the reason. I had a hard time finding a focusable green line laser.

    My focusable corner is 90 degrees and is 24"x36", calibration was no problem.

    My camera is a Logitech HD Portable 1080p Webcam C615 with Autofocus

    I thought about doing the scan in pieces, and that is worth a try.

Question: Is my usage of the trial version affecting my resolution? Or is the resolution only dumbed down after saving the file?
schneb
 
Posts: 5
Joined: Tue Jun 17, 2014 5:32 pm

Re: My First Scan - Sad

Postby WalterMo » Thu Jun 19, 2014 8:19 pm

„I had a hard time finding a focusable green line laser.“

Yes, focusable green line lasers aren't cheap. Have you looked into the DAVID shop?
https://ssl.david-vision-systems.de/sho ... gory/Laser

„My focusable corner is 90 degrees and is 24"x 36", calibration was no problem.“

A successful calibration is normally no problem. But DAVID cannot recognize if the 90° are really true. A precise 90° corner to build is your job! :wink:

„My camera is a Logitech HD Portable 1080p Webcam C615 with Autofocus.“

Regarding 'Auto focus': Disable this „feature“!! Also disable 'Right light' and the other 'Auto' modes in the camera settings.

„Question: Is my usage of the trial version affecting my resolution? Or is the resolution only dumbed down after saving the file?“

If you don't have the DAVID license you can scan up to the highest camera resolution. But if you save this scan its resolution is reduced to only 240 x 320 pixels! If you then again upload these scans for the alignment you will immediately see this limitation. A fusion is also possible but it's not possible to save its result.
User avatar
WalterMo
Moderator
 
Posts: 2363
Joined: Mon Apr 02, 2007 6:52 pm
Location: Braunschweig, Germany

Re: My First Scan - Sad

Postby schneb » Thu Jun 19, 2014 9:43 pm

Here is my setup. At the time I did my first scan, all the wrinkles were not there. (boo)

I am going to try again with a different setup. Thanks for the tips regarding the camera. I will make those adjustments and try again.
Attachments
scan-1.jpg
schneb
 
Posts: 5
Joined: Tue Jun 17, 2014 5:32 pm

Re: My First Scan - Sad

Postby WalterMo » Thu Jun 19, 2014 9:59 pm

I cannot see any wrinkles on the man's face. :wink:

Tip 1: Hold the laser steeper. Means increase the intersection angle. It should be about 30°.
Tip 2: Focus the camera sharp on the object, not on the calibration corner walls. That means before the calibration of the empty corner put the bust in the corner, focus the camera on it and then remove the bust. Replace the bust after calibration at the same place as before. Don't change the camera settings after calibration.
User avatar
WalterMo
Moderator
 
Posts: 2363
Joined: Mon Apr 02, 2007 6:52 pm
Location: Braunschweig, Germany

Re: My First Scan - Sad

Postby schneb » Fri Jun 20, 2014 4:35 pm

Heh heh...

Your suggestions make a lot of sense. I am going to give that a try this weekend. The angle of the laser makes sense. I wondered "how does the software know if all it sees through the camera is a straight line?" The 30 degree angle makes more sense now.

Thanks a lot!
schneb
 
Posts: 5
Joined: Tue Jun 17, 2014 5:32 pm


Return to Camera Calibration

Who is online

Users browsing this forum: No registered users and 2 guests